Merge commit 'refs/pull/10803/merge' of github.com:github/codeql into HEAD

Ruby: fix self variables in blocks

.bazelrc

@@ -1,3 +1,3 @@
-build --repo_env=CC=clang --repo_env=CXX=clang++ --copt="-std=c++17"
+build --repo_env=CC=clang --repo_env=CXX=clang++ --cxxopt="-std=c++17"
 
 try-import %workspace%/local.bazelrc

.github/labeler.yml

@@ -42,3 +42,4 @@ documentation:
 
 "QL-for-QL":
   - ql/**/*
+  - .github/workflows/ql-for-ql*

.github/workflows/check-qldoc.yml

@@ -27,7 +27,8 @@ jobs:
         run: |
           EXIT_CODE=0
           # TODO: remove the swift exception from the regex when we fix generated QLdoc
-          changed_lib_packs="$(git diff --name-only --diff-filter=ACMRT HEAD^ HEAD | { grep -Po '^(?!swift)[a-z]*/ql/lib' || true; } | sort -u)"
+          # TODO: remove the shared exception from the regex when coverage of qlpacks without dbschemes is supported
+          changed_lib_packs="$(git diff --name-only --diff-filter=ACMRT HEAD^ HEAD | { grep -Po '^(?!(swift|shared))[a-z]*/ql/lib' || true; } | sort -u)"
           for pack_dir in ${changed_lib_packs}; do
             lang="${pack_dir%/ql/lib}"
             codeql generate library-doc-coverage --output="${RUNNER_TEMP}/${lang}-current.txt" --dir="${pack_dir}"

.github/workflows/close-stale.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/stale@v5
+    - uses: actions/stale@v6
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         stale-issue-message: 'This issue is stale because it has been open 14 days with no activity. Comment or remove the `Stale` label in order to avoid having this issue closed in 7 days.'

.github/workflows/codeql-analysis.yml

@@ -56,7 +56,7 @@ jobs:
     #    uses a compiled language
 
     - run: |
-       dotnet build csharp /p:UseSharedCompilation=false
+       dotnet build csharp
 
     - name: Perform CodeQL Analysis
       uses: github/codeql-action/analyze@main

.github/workflows/csv-coverage-metrics.yml

@@ -55,7 +55,7 @@ jobs:
           DATABASE="${{ runner.temp }}/csharp-database"
           PROJECT="${{ runner.temp }}/csharp-project"
           dotnet new classlib --language=C# --output="$PROJECT"
-          codeql database create "$DATABASE" --language=csharp --source-root="$PROJECT" --command 'dotnet build /t:rebuild csharp-project.csproj /p:UseSharedCompilation=false'
+          codeql database create "$DATABASE" --language=csharp --source-root="$PROJECT" --command 'dotnet build /t:rebuild csharp-project.csproj'
       - name: Capture coverage information
         run: |
           DATABASE="${{ runner.temp }}/csharp-database"

.github/workflows/go-tests.yml

@@ -11,10 +11,10 @@ jobs:
     name: Test Linux (Ubuntu)
     runs-on: ubuntu-latest
     steps:
-      - name: Set up Go 1.18.1
+      - name: Set up Go 1.19
         uses: actions/setup-go@v3
         with:
-          go-version: 1.18.1
+          go-version: 1.19
         id: go
 
       - name: Check out code
@@ -43,7 +43,7 @@ jobs:
           env QHELP_OUT_DIR=qhelp-out make qhelp-to-markdown
 
       - name: Upload qhelp markdown
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: qhelp-markdown
           path: go/qhelp-out/**/*.md
@@ -57,10 +57,10 @@ jobs:
     name: Test MacOS
     runs-on: macos-latest
     steps:
-      - name: Set up Go 1.18.1
+      - name: Set up Go 1.19
         uses: actions/setup-go@v3
         with:
-          go-version: 1.18.1
+          go-version: 1.19
         id: go
 
       - name: Check out code
@@ -87,10 +87,10 @@ jobs:
     name: Test Windows
     runs-on: windows-2019
     steps:
-      - name: Set up Go 1.18.1
+      - name: Set up Go 1.19
         uses: actions/setup-go@v3
         with:
-          go-version: 1.18.1
+          go-version: 1.19
         id: go
 
       - name: Check out code

.github/workflows/qhelp-pr-preview.yml

@@ -27,7 +27,7 @@ on:
       - main
       - "rc/*"
     paths:
-      - "ruby/**/*.qhelp"
+      - "**/*.qhelp"
 
 jobs:
   qhelp:
@@ -52,7 +52,7 @@ jobs:
         id: changes
         run: |
           (git diff -z --name-only --diff-filter=ACMRT HEAD~1 HEAD | grep -z '.qhelp$' | grep -z -v '.inc.qhelp';
-           git diff -z --name-only --diff-filter=ACMRT HEAD~1 HEAD | grep -z '.inc.qhelp$' | xargs --null -rn1 basename | xargs --null -rn1 git grep -z -l) |
+           git diff -z --name-only --diff-filter=ACMRT HEAD~1 HEAD | grep -z '.inc.qhelp$' | xargs --null -rn1 basename -z | xargs --null -rn1 git grep -z -l) |
            grep -z '.qhelp$' | grep -z -v '^-' | sort -z -u > "${RUNNER_TEMP}/paths.txt"
 
       - name: QHelp preview

.github/workflows/ql-for-ql-build.yml

@@ -5,6 +5,13 @@ on:
     branches: [main]
   pull_request:
     branches: [main]
+    paths:
+      - "ql/**"
+      - "**.qll"
+      - "**.ql"
+      - "**.dbscheme"
+      - "**/qlpack.yml"
+      - ".github/workflows/ql-for-ql-build.yml"
 
 env:
   CARGO_TERM_COLOR: always
@@ -17,7 +24,7 @@ jobs:
       - uses: actions/checkout@v3
       - name: Find codeql
         id: find-codeql
-        uses: github/codeql-action/init@aa93aea877e5fb8841bcb1193f672abf6e9f2980
+        uses: github/codeql-action/init@71a8b35ff4c80fcfcd05bc1cd932fe3c08f943ca
         with:
           languages: javascript # does not matter
       - name: Get CodeQL version
@@ -27,30 +34,37 @@ jobs:
         shell: bash
         env:
           CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
+      - name: Cache entire pack
+        id: cache-pack
+        uses: actions/cache@v3
+        with:
+          path: ${{ runner.temp }}/pack
+          key: ${{ runner.os }}-pack-${{ hashFiles('ql/**/Cargo.lock') }}-${{ hashFiles('ql/**/*.rs') }}-${{ hashFiles('ql/**/*.ql*') }}-${{ hashFiles('ql/**/qlpack.yml') }}-${{ hashFiles('ql/ql/src/ql.dbscheme*') }}-${{ steps.get-codeql-version.outputs.version }}--${{ hashFiles('.github/workflows/ql-for-ql-build.yml') }}
       - name: Cache queries
+        if: steps.cache-pack.outputs.cache-hit != 'true'
         id: cache-queries
         uses: actions/cache@v3
         with:
-          path: ${{ runner.temp }}/query-pack.zip
-          key: queries-${{ hashFiles('ql/**/*.ql*') }}-${{ hashFiles('ql/**/qlpack.yml') }}-${{ hashFiles('ql/ql/src/ql.dbscheme*') }}-${{ steps.get-codeql-version.outputs.version }}
+          path: ${{ runner.temp }}/queries
+          key: queries-${{ hashFiles('ql/**/*.ql*') }}-${{ hashFiles('ql/**/qlpack.yml') }}-${{ hashFiles('ql/ql/src/ql.dbscheme*') }}-${{ steps.get-codeql-version.outputs.version }}--${{ hashFiles('.github/workflows/ql-for-ql-build.yml') }}
       - name: Build query pack
-        if: steps.cache-queries.outputs.cache-hit != 'true'
+        if: steps.cache-queries.outputs.cache-hit != 'true' && steps.cache-pack.outputs.cache-hit != 'true'
         run: |
           cd ql/ql/src
-          "${CODEQL}" pack create
-          cd .codeql/pack/codeql/ql/0.0.0
-          zip "${PACKZIP}" -r .
+          "${CODEQL}" pack create -j 16
+          mv .codeql/pack/codeql/ql/0.0.0 ${{ runner.temp }}/queries
+        env:
+          CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
+      - name: Move cache queries to pack
+        if: steps.cache-pack.outputs.cache-hit != 'true'
+        run: |
+          cp -r ${{ runner.temp }}/queries ${{ runner.temp }}/pack
         env:
           CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
-          PACKZIP: ${{ runner.temp }}/query-pack.zip
-      - name: Upload query pack
-        uses: actions/upload-artifact@v3
-        with:
-          name: query-pack-zip
-          path: ${{ runner.temp }}/query-pack.zip
 
       ### Build the extractor ###
       - name: Cache entire extractor
+        if: steps.cache-pack.outputs.cache-hit != 'true'
         id: cache-extractor
         uses: actions/cache@v3
         with:
@@ -61,7 +75,7 @@ jobs:
             ql/target/release/ql-extractor.exe
           key: ${{ runner.os }}-extractor-${{ hashFiles('ql/**/Cargo.lock') }}-${{ hashFiles('ql/**/*.rs') }}
       - name: Cache cargo
-        if: steps.cache-extractor.outputs.cache-hit != 'true'
+        if: steps.cache-extractor.outputs.cache-hit != 'true' && steps.cache-pack.outputs.cache-hit != 'true'
         uses: actions/cache@v3
         with:
           path: |
@@ -70,75 +84,38 @@ jobs:
             ql/target
           key: ${{ runner.os }}-rust-cargo-${{ hashFiles('ql/**/Cargo.lock') }}
       - name: Check formatting
-        if: steps.cache-extractor.outputs.cache-hit != 'true'
+        if: steps.cache-extractor.outputs.cache-hit != 'true' && steps.cache-pack.outputs.cache-hit != 'true'
         run: cd ql; cargo fmt --all -- --check
       - name: Build
-        if: steps.cache-extractor.outputs.cache-hit != 'true'
+        if: steps.cache-extractor.outputs.cache-hit != 'true' && steps.cache-pack.outputs.cache-hit != 'true'
         run: cd ql; cargo build --verbose
       - name: Run tests
-        if: steps.cache-extractor.outputs.cache-hit != 'true'
+        if: steps.cache-extractor.outputs.cache-hit != 'true' && steps.cache-pack.outputs.cache-hit != 'true'
         run: cd ql; cargo test --verbose
       - name: Release build
-        if: steps.cache-extractor.outputs.cache-hit != 'true'
+        if: steps.cache-extractor.outputs.cache-hit != 'true' && steps.cache-pack.outputs.cache-hit != 'true'
         run: cd ql; cargo build --release
       - name: Generate dbscheme
-        if: steps.cache-extractor.outputs.cache-hit != 'true'
+        if: steps.cache-extractor.outputs.cache-hit != 'true' && steps.cache-pack.outputs.cache-hit != 'true'
         run: ql/target/release/ql-generator --dbscheme ql/ql/src/ql.dbscheme --library ql/ql/src/codeql_ql/ast/internal/TreeSitter.qll
-      - uses: actions/upload-artifact@v3
-        with:
-          name: extractor-ubuntu-latest
-          path: |
-            ql/target/release/ql-autobuilder
-            ql/target/release/ql-autobuilder.exe
-            ql/target/release/ql-extractor
-            ql/target/release/ql-extractor.exe
-          retention-days: 1
 
       ### Package the queries and extractor ###
-      - uses: actions/download-artifact@v3
-        with:
-          name: query-pack-zip
-          path: query-pack-zip
-      - uses: actions/download-artifact@v3
-        with:
-          name: extractor-ubuntu-latest
-          path: linux64
-      - run: |
-          unzip query-pack-zip/*.zip -d pack
-          cp -r ql/codeql-extractor.yml ql/tools ql/ql/src/ql.dbscheme.stats pack/
-          mkdir -p pack/tools/linux64
-          if [[ -f linux64/ql-autobuilder ]]; then
-            cp linux64/ql-autobuilder pack/tools/linux64/autobuilder
-            chmod +x pack/tools/linux64/autobuilder
-          fi
-          if [[ -f linux64/ql-extractor ]]; then
-            cp linux64/ql-extractor pack/tools/linux64/extractor
-            chmod +x pack/tools/linux64/extractor
-          fi
-          cd pack
-          zip -rq ../codeql-ql.zip .
-      - uses: actions/upload-artifact@v3
-        with:
-          name: codeql-ql-pack
-          path: codeql-ql.zip
-          retention-days: 1
+      - name: Package pack
+        if: steps.cache-pack.outputs.cache-hit != 'true'
+        run: |
+          cp -r ql/codeql-extractor.yml ql/tools ql/ql/src/ql.dbscheme.stats ${PACK}/
+          mkdir -p ${PACK}/tools/linux64
+          cp ql/target/release/ql-autobuilder  ${PACK}/tools/linux64/autobuilder
+          cp ql/target/release/ql-extractor ${PACK}/tools/linux64/extractor
+          chmod +x ${PACK}/tools/linux64/autobuilder
+          chmod +x ${PACK}/tools/linux64/extractor
+        env:
+          PACK: ${{ runner.temp }}/pack
 
       ### Run the analysis ###
-      - name: Download pack
-        uses: actions/download-artifact@v3
-        with:
-          name: codeql-ql-pack
-          path: ${{ runner.temp }}/codeql-ql-pack-artifact
-
-      - name: Prepare pack
-        run: |
-          unzip "${PACK_ARTIFACT}/*.zip" -d "${PACK}"
-        env:
-          PACK_ARTIFACT: ${{ runner.temp }}/codeql-ql-pack-artifact
-          PACK: ${{ runner.temp }}/pack
       - name: Hack codeql-action options
         run: |
-          JSON=$(jq -nc --arg pack "${PACK}" '.database."run-queries"=["--search-path", $pack] | .resolve.queries=["--search-path", $pack] | .resolve.extractor=["--search-path", $pack] | .database.init=["--search-path", $pack]')
+          JSON=$(jq -nc --arg pack "${PACK}" '.database."run-queries"=["--search-path", $pack] | .resolve.queries=["--search-path", $pack] | .resolve.extractor=["--search-path", $pack] | .resolve.languages=["--search-path", $pack] | .database.init=["--search-path", $pack]')
           echo "CODEQL_ACTION_EXTRA_OPTIONS=${JSON}" >> ${GITHUB_ENV}
         env:
           PACK: ${{ runner.temp }}/pack
@@ -146,31 +123,36 @@ jobs:
       - name: Create CodeQL config file
         run: |
           echo "paths-ignore:" >> ${CONF}
-          echo "  - ql/ql/test" >> ${CONF} 
-          echo "  - \"*/ql/lib/upgrades/\"" >> ${CONF} 
+          echo "  - ql/ql/test" >> ${CONF}
+          echo "  - \"*/ql/lib/upgrades/\"" >> ${CONF}
           echo "disable-default-queries: true" >> ${CONF}
-          echo "packs:" >> ${CONF}
-          echo "  - codeql/ql" >> ${CONF}
+          echo "queries:" >> ${CONF}
+          echo "  - uses: ./ql/ql/src/codeql-suites/ql-code-scanning.qls" >> ${CONF}
           echo "Config file: "
           cat ${CONF}
-        env: 
+        env:
           CONF: ./ql-for-ql-config.yml
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@aa93aea877e5fb8841bcb1193f672abf6e9f2980
+        uses: github/codeql-action/init@71a8b35ff4c80fcfcd05bc1cd932fe3c08f943ca
         with:
           languages: ql
           db-location: ${{ runner.temp }}/db
           config-file: ./ql-for-ql-config.yml
+      - name: Move pack cache
+        run: |
+          cp -r ${PACK}/.cache ql/ql/src/.cache
+        env:
+          PACK: ${{ runner.temp }}/pack
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@aa93aea877e5fb8841bcb1193f672abf6e9f2980
-        with: 
+        uses: github/codeql-action/analyze@71a8b35ff4c80fcfcd05bc1cd932fe3c08f943ca
+        with:
           category: "ql-for-ql"
       - name: Copy sarif file to CWD
         run: cp ../results/ql.sarif ./ql-for-ql.sarif
       - name: Fixup the $scema in sarif  # Until https://github.com/microsoft/sarif-vscode-extension/pull/436/ is part in a stable release
         run: |
-          sed -i 's/\$schema.*/\$schema": "https:\/\/raw.githubusercontent.com\/oasis-tcs\/sarif-spec\/master\/Schemata\/sarif-schema-2.1.0",/' ql-for-ql.sarif 
+          sed -i 's/\$schema.*/\$schema": "https:\/\/raw.githubusercontent.com\/oasis-tcs\/sarif-spec\/master\/Schemata\/sarif-schema-2.1.0",/' ql-for-ql.sarif
       - name: Sarif as artifact
         uses: actions/upload-artifact@v3
         with:

.github/workflows/ql-for-ql-dataset_measure.yml

@@ -25,7 +25,7 @@ jobs:
 
       - name: Find codeql
         id: find-codeql
-        uses: github/codeql-action/init@aa93aea877e5fb8841bcb1193f672abf6e9f2980
+        uses: github/codeql-action/init@71a8b35ff4c80fcfcd05bc1cd932fe3c08f943ca
         with:
           languages: javascript # does not matter
       - uses: actions/cache@v3

.github/workflows/ql-for-ql-tests.yml

@@ -22,7 +22,7 @@ jobs:
       - uses: actions/checkout@v3
       - name: Find codeql
         id: find-codeql
-        uses: github/codeql-action/init@aa93aea877e5fb8841bcb1193f672abf6e9f2980
+        uses: github/codeql-action/init@71a8b35ff4c80fcfcd05bc1cd932fe3c08f943ca
         with:
           languages: javascript # does not matter
       - uses: actions/cache@v3
@@ -44,7 +44,7 @@ jobs:
           CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
       - name: Check QL formatting
         run: |
-          find ql/ql "(" -name "*.ql" -or -name "*.qll" ")" -print0 | xargs -0 "${CODEQL}" query format --check-only
+          find ql/ql/src "(" -name "*.ql" -or -name "*.qll" ")" -print0 | xargs -0 "${CODEQL}" query format --check-only
         env:
           CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
       - name: Check QL compilation

.github/workflows/ruby-build.yml

@@ -95,6 +95,7 @@ jobs:
         uses: ./.github/actions/fetch-codeql
       - name: Build Query Pack
         run: |
+          codeql pack create ../shared/ssa --output target/packs
           codeql pack create ql/lib --output target/packs
           codeql pack install ql/src
           codeql pack create ql/src --output target/packs
@@ -196,7 +197,7 @@ jobs:
       - name: Prepare test files
         shell: bash
         run: |
-          echo "import ruby select count(File f)" > "test.ql"
+          echo "import codeql.ruby.AST select count(File f)" > "test.ql"
           echo "| 4 |" > "test.expected"
           echo 'name: sample-tests
           version: 0.0.0

.github/workflows/swift-codegen.yml

@@ -4,6 +4,8 @@ on:
   pull_request:
     paths:
       - "swift/**"
+      - "misc/bazel/**"
+      - "*.bazel*"
       - .github/workflows/swift-codegen.yml
       - .github/actions/fetch-codeql/action.yml
     branches:

.github/workflows/swift-integration-tests.yml

@@ -4,6 +4,8 @@ on:
   pull_request:
     paths:
       - "swift/**"
+      - "misc/bazel/**"
+      - "*.bazel*"
       - .github/workflows/swift-integration-tests.yml
       - .github/actions/fetch-codeql/action.yml
       - codeql-workspace.yml
@@ -30,6 +32,14 @@ jobs:
       - name: Build Swift extractor
         run: |
           bazel run //swift:create-extractor-pack
+      - name: Get Swift version
+        id: get_swift_version
+        run: |
+          VERSION=$(bazel run //swift/extractor -- --version | sed -ne 's/.*version \(\S*\).*/\1/p')
+          echo "::set-output name=version::$VERSION"
+      - uses: swift-actions/setup-swift@v1
+        with:
+          swift-version: "${{steps.get_swift_version.outputs.version}}"
       - name: Run integration tests
         run: |
           python integration-tests/runner.py

.github/workflows/swift-qltest.yml

@@ -4,6 +4,8 @@ on:
   pull_request:
     paths:
       - "swift/**"
+      - "misc/bazel/**"
+      - "*.bazel*"
       - .github/workflows/swift-qltest.yml
       - .github/actions/fetch-codeql/action.yml
       - codeql-workspace.yml

CODEOWNERS

@@ -30,6 +30,8 @@
 
 # Bazel (excluding BUILD.bazel files)
 WORKSPACE.bazel @github/codeql-ci-reviewers
+.bazelversion @github/codeql-ci-reviewers
+.bazelrc @github/codeql-ci-reviewers
 **/*.bzl @github/codeql-ci-reviewers
 
 # Documentation etc

README.md

@@ -4,8 +4,7 @@ This open source repository contains the standard CodeQL libraries and queries t
 
 ## How do I learn CodeQL and run queries?
 
-There is [extensive documentation](https://codeql.github.com/docs/) on getting started with writing CodeQL.
-You can use the [CodeQL for Visual Studio Code](https://codeql.github.com/docs/codeql-for-visual-studio-code/) extension or the [interactive query console](https://lgtm.com/help/lgtm/using-query-console) on LGTM.com (Semmle Legacy product) to try out your queries on any open source project that's currently being analyzed.
+There is [extensive documentation](https://codeql.github.com/docs/) on getting started with writing CodeQL using the [CodeQL extension for Visual Studio Code](https://codeql.github.com/docs/codeql-for-visual-studio-code/) and the [CodeQL CLI](https://codeql.github.com/docs/codeql-cli/).
 
 ## Contributing
 

codeql-workspace.yml

@@ -4,6 +4,7 @@ provide:
   - "*/ql/test/qlpack.yml"
   - "*/ql/examples/qlpack.yml"
   - "*/ql/consistency-queries/qlpack.yml"
+  - "shared/*/qlpack.yml"
   - "cpp/ql/test/query-tests/Security/CWE/CWE-190/semmle/tainted/qlpack.yml"
   - "go/ql/config/legacy-support/qlpack.yml"
   - "go/build/codeql-extractor-go/codeql-extractor.yml"

config/identical-files.json

@@ -17,6 +17,10 @@
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl2.qll",
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl3.qll",
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl4.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl2.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl3.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl4.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl2.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl3.qll",
@@ -29,13 +33,16 @@
     "python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl4.qll",
     "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll",
     "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl2.qll",
-    "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImplForLibraries.qll",
+    "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImplForRegExp.qll",
+    "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImplForHttpClientLibraries.qll",
+    "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImplForPathname.qll",
     "swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll"
   ],
   "DataFlow Java/C++/C#/Python Common": [
     "java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImplCommon.qll",
     "cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImplCommon.qll",
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImplCommon.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImplCommon.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImplCommon.qll",
     "python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImplCommon.qll",
     "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImplCommon.qll",
@@ -47,6 +54,9 @@
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/tainttracking1/TaintTrackingImpl.qll",
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/tainttracking2/TaintTrackingImpl.qll",
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/tainttracking3/TaintTrackingImpl.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking1/TaintTrackingImpl.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking2/TaintTrackingImpl.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking3/TaintTrackingImpl.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/tainttracking1/TaintTrackingImpl.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/tainttracking2/TaintTrackingImpl.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/tainttracking3/TaintTrackingImpl.qll",
@@ -60,22 +70,23 @@
     "python/ql/lib/semmle/python/dataflow/new/internal/tainttracking3/TaintTrackingImpl.qll",
     "python/ql/lib/semmle/python/dataflow/new/internal/tainttracking4/TaintTrackingImpl.qll",
     "ruby/ql/lib/codeql/ruby/dataflow/internal/tainttracking1/TaintTrackingImpl.qll",
-    "ruby/ql/lib/codeql/ruby/dataflow/internal/tainttrackingforlibraries/TaintTrackingImpl.qll",
     "swift/ql/lib/codeql/swift/dataflow/internal/tainttracking1/TaintTrackingImpl.qll"
   ],
   "DataFlow Java/C++/C#/Python Consistency checks": [
     "java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImplConsistency.qll",
     "cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImplConsistency.qll",
     "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImplConsistency.qll",
+    "cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImplConsistency.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImplConsistency.qll",
     "python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImplConsistency.qll",
     "ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImplConsistency.qll",
     "swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImplConsistency.qll"
   ],
-  "DataFlow Java/C# Flow Summaries": [
+  "DataFlow Java/C#/Ruby/Python/Swift Flow Summaries": [
     "java/ql/lib/semmle/code/java/dataflow/internal/FlowSummaryImpl.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/FlowSummaryImpl.qll",
     "ruby/ql/lib/codeql/ruby/dataflow/internal/FlowSummaryImpl.qll",
+    "python/ql/lib/semmle/python/dataflow/new/internal/FlowSummaryImpl.qll",
     "swift/ql/lib/codeql/swift/dataflow/internal/FlowSummaryImpl.qll"
   ],
   "SsaReadPosition Java/C#": [
@@ -460,15 +471,6 @@
     "javascript/ql/lib/IDEContextual.qll",
     "python/ql/lib/analysis/IDEContextual.qll"
   ],
-  "SSA C#": [
-    "csharp/ql/lib/semmle/code/csharp/dataflow/internal/SsaImplCommon.qll",
-    "csharp/ql/lib/semmle/code/csharp/controlflow/internal/pressa/SsaImplCommon.qll",
-    "csharp/ql/lib/semmle/code/csharp/dataflow/internal/basessa/SsaImplCommon.qll",
-    "csharp/ql/lib/semmle/code/cil/internal/SsaImplCommon.qll",
-    "ruby/ql/lib/codeql/ruby/dataflow/internal/SsaImplCommon.qll",
-    "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaImplCommon.qll",
-    "swift/ql/lib/codeql/swift/dataflow/internal/SsaImplCommon.qll"
-  ],
   "CryptoAlgorithms Python/JS/Ruby": [
     "javascript/ql/lib/semmle/javascript/security/CryptoAlgorithms.qll",
     "python/ql/lib/semmle/python/concepts/CryptoAlgorithms.qll",
@@ -485,28 +487,39 @@
     "ruby/ql/lib/codeql/ruby/security/internal/SensitiveDataHeuristics.qll"
   ],
   "ReDoS Util Python/JS/Ruby/Java": [
-    "javascript/ql/lib/semmle/javascript/security/performance/ReDoSUtil.qll",
-    "python/ql/lib/semmle/python/security/performance/ReDoSUtil.qll",
-    "ruby/ql/lib/codeql/ruby/security/performance/ReDoSUtil.qll",
-    "java/ql/lib/semmle/code/java/security/performance/ReDoSUtil.qll"
+    "javascript/ql/lib/semmle/javascript/security/regexp/NfaUtils.qll",
+    "python/ql/lib/semmle/python/security/regexp/NfaUtils.qll",
+    "ruby/ql/lib/codeql/ruby/security/regexp/NfaUtils.qll",
+    "java/ql/lib/semmle/code/java/security/regexp/NfaUtils.qll"
   ],
   "ReDoS Exponential Python/JS/Ruby/Java": [
-    "javascript/ql/lib/semmle/javascript/security/performance/ExponentialBackTracking.qll",
-    "python/ql/lib/semmle/python/security/performance/ExponentialBackTracking.qll",
-    "ruby/ql/lib/codeql/ruby/security/performance/ExponentialBackTracking.qll",
-    "java/ql/lib/semmle/code/java/security/performance/ExponentialBackTracking.qll"
+    "javascript/ql/lib/semmle/javascript/security/regexp/ExponentialBackTracking.qll",
+    "python/ql/lib/semmle/python/security/regexp/ExponentialBackTracking.qll",
+    "ruby/ql/lib/codeql/ruby/security/regexp/ExponentialBackTracking.qll",
+    "java/ql/lib/semmle/code/java/security/regexp/ExponentialBackTracking.qll"
   ],
   "ReDoS Polynomial Python/JS/Ruby/Java": [
-    "javascript/ql/lib/semmle/javascript/security/performance/SuperlinearBackTracking.qll",
-    "python/ql/lib/semmle/python/security/performance/SuperlinearBackTracking.qll",
-    "ruby/ql/lib/codeql/ruby/security/performance/SuperlinearBackTracking.qll",
-    "java/ql/lib/semmle/code/java/security/performance/SuperlinearBackTracking.qll"
+    "javascript/ql/lib/semmle/javascript/security/regexp/SuperlinearBackTracking.qll",
+    "python/ql/lib/semmle/python/security/regexp/SuperlinearBackTracking.qll",
+    "ruby/ql/lib/codeql/ruby/security/regexp/SuperlinearBackTracking.qll",
+    "java/ql/lib/semmle/code/java/security/regexp/SuperlinearBackTracking.qll"
+  ],
+  "RegexpMatching Python/JS/Ruby": [
+    "javascript/ql/lib/semmle/javascript/security/regexp/RegexpMatching.qll",
+    "python/ql/lib/semmle/python/security/regexp/RegexpMatching.qll",
+    "ruby/ql/lib/codeql/ruby/security/regexp/RegexpMatching.qll"
   ],
   "BadTagFilterQuery Python/JS/Ruby": [
     "javascript/ql/lib/semmle/javascript/security/BadTagFilterQuery.qll",
     "python/ql/lib/semmle/python/security/BadTagFilterQuery.qll",
     "ruby/ql/lib/codeql/ruby/security/BadTagFilterQuery.qll"
   ],
+  "OverlyLargeRange Python/JS/Ruby/Java": [
+    "javascript/ql/lib/semmle/javascript/security/OverlyLargeRangeQuery.qll",
+    "python/ql/lib/semmle/python/security/OverlyLargeRangeQuery.qll",
+    "ruby/ql/lib/codeql/ruby/security/OverlyLargeRangeQuery.qll",
+    "java/ql/lib/semmle/code/java/security/OverlyLargeRangeQuery.qll"
+  ],
   "CFG": [
     "csharp/ql/lib/semmle/code/csharp/controlflow/internal/ControlFlowGraphImplShared.qll",
     "ruby/ql/lib/codeql/ruby/controlflow/internal/ControlFlowGraphImplShared.qll",
@@ -529,7 +542,7 @@
     "java/ql/lib/semmle/code/java/dataflow/internal/AccessPathSyntax.qll",
     "javascript/ql/lib/semmle/javascript/frameworks/data/internal/AccessPathSyntax.qll",
     "ruby/ql/lib/codeql/ruby/dataflow/internal/AccessPathSyntax.qll",
-    "python/ql/lib/semmle/python/frameworks/data/internal/AccessPathSyntax.qll",
+    "python/ql/lib/semmle/python/dataflow/new/internal/AccessPathSyntax.qll",
     "swift/ql/lib/codeql/swift/dataflow/internal/AccessPathSyntax.qll"
   ],
   "IncompleteUrlSubstringSanitization": [
@@ -573,18 +586,22 @@
   ],
   "Swift declarations test file": [
     "swift/ql/test/extractor-tests/declarations/declarations.swift",
-    "swift/ql/test/library-tests/parent/declarations.swift"
+    "swift/ql/test/library-tests/ast/declarations.swift"
   ],
   "Swift statements test file": [
     "swift/ql/test/extractor-tests/statements/statements.swift",
-    "swift/ql/test/library-tests/parent/statements.swift"
+    "swift/ql/test/library-tests/ast/statements.swift"
   ],
   "Swift expressions test file": [
     "swift/ql/test/extractor-tests/expressions/expressions.swift",
-    "swift/ql/test/library-tests/parent/expressions.swift"
+    "swift/ql/test/library-tests/ast/expressions.swift"
   ],
   "Swift patterns test file": [
     "swift/ql/test/extractor-tests/patterns/patterns.swift",
-    "swift/ql/test/library-tests/parent/patterns.swift"
+    "swift/ql/test/library-tests/ast/patterns.swift"
+  ],
+  "IncompleteMultiCharacterSanitization JS/Ruby": [
+    "javascript/ql/lib/semmle/javascript/security/IncompleteMultiCharacterSanitizationQuery.qll",
+    "ruby/ql/lib/codeql/ruby/security/IncompleteMultiCharacterSanitizationQuery.qll"
   ]
-}
+}

cpp/autobuilder/Semmle.Autobuild.Cpp.Tests/BuildScripts.cs

@@ -299,7 +299,7 @@ namespace Semmle.Autobuild.Cpp.Tests
         {
             Actions.RunProcess[@"cmd.exe /C nuget restore C:\Project\test.sln -DisableParallelProcessing"] = 1;
             Actions.RunProcess[@"cmd.exe /C C:\Project\.nuget\nuget.exe restore C:\Project\test.sln -DisableParallelProcessing"] = 0;
-            Actions.RunProcess[@"cmd.exe /C CALL ^""C:\Program Files ^(x86^)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat^"" && set Platform=&& type NUL && C:\odasa\tools\odasa index --auto msbuild C:\Project\test.sln /p:UseSharedCompilation=false /t:rebuild /p:Platform=""x86"" /p:Configuration=""Release"" /p:MvcBuildViews=true"] = 0;
+            Actions.RunProcess[@"cmd.exe /C CALL ^""C:\Program Files ^(x86^)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat^"" && set Platform=&& type NUL && C:\odasa\tools\odasa index --auto msbuild C:\Project\test.sln /t:rebuild /p:Platform=""x86"" /p:Configuration=""Release"" /p:MvcBuildViews=true"] = 0;
             Actions.RunProcessOut[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe -prerelease -legacy -property installationPath"] = "";
             Actions.RunProcess[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe -prerelease -legacy -property installationPath"] = 1;
             Actions.RunProcess[@"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe -prerelease -legacy -property installationVersion"] = 0;

cpp/downgrades/625f706f2a44ae8dc3fc168bfe2637e65c30b012/exprs.ql

@@ -0,0 +1,17 @@
+class Expr extends @expr {
+  string toString() { none() }
+}
+
+class Location extends @location_expr {
+  string toString() { none() }
+}
+
+predicate isExprWithNewBuiltin(Expr expr) {
+  exists(int kind | exprs(expr, kind, _) | 336 <= kind and kind <= 362)
+}
+
+from Expr expr, int kind, int kind_new, Location location
+where
+  exprs(expr, kind, location) and
+  if isExprWithNewBuiltin(expr) then kind_new = 1 else kind_new = kind
+select expr, kind_new, location

cpp/downgrades/625f706f2a44ae8dc3fc168bfe2637e65c30b012/upgrade.properties

@@ -0,0 +1,3 @@
+description: Add new builtin operations
+compatibility: partial
+exprs.rel: run exprs.qlo

cpp/downgrades/73af5058c6899dcdb05754c27ca966aeb3a68c94/exprs.ql

@@ -0,0 +1,13 @@
+class Expr extends @expr {
+  string toString() { none() }
+}
+
+class Location extends @location_expr {
+  string toString() { none() }
+}
+
+from Expr expr, int kind, int kind_new, Location location
+where
+  exprs(expr, kind, location) and
+  if expr instanceof @blockassignexpr then kind_new = 0 else kind_new = kind
+select expr, kind_new, location

cpp/downgrades/73af5058c6899dcdb05754c27ca966aeb3a68c94/upgrade.properties

@@ -0,0 +1,3 @@
+description: Support block assignment
+compatibility: partial
+exprs.rel: run exprs.qlo

cpp/downgrades/f96ad9b2da43bbc9e55a72a165febd270ae07981/upgrade.properties

@@ -0,0 +1,3 @@
+description: Add relation for orphaned local variables
+compatibility: full
+orphaned_variables.rel: delete

cpp/ql/lib/CHANGELOG.md

@@ -1,3 +1,40 @@
+## 0.4.1
+
+No user-facing changes.
+
+## 0.4.0
+
+### Deprecated APIs
+
+* Some classes/modules with upper-case acronyms in their name have been renamed to follow our style-guide. 
+  The old name still exists as a deprecated alias.
+
+### New Features
+
+* Added subclasses of `BuiltInOperations` for `__is_same`, `__is_function`, `__is_layout_compatible`, `__is_pointer_interconvertible_base_of`, `__is_array`, `__array_rank`, `__array_extent`, `__is_arithmetic`, `__is_complete_type`, `__is_compound`, `__is_const`, `__is_floating_point`, `__is_fundamental`, `__is_integral`, `__is_lvalue_reference`, `__is_member_function_pointer`, `__is_member_object_pointer`, `__is_member_pointer`, `__is_object`, `__is_pointer`, `__is_reference`, `__is_rvalue_reference`, `__is_scalar`, `__is_signed`, `__is_unsigned`, `__is_void`, and `__is_volatile`.
+
+### Bug Fixes
+
+* Fixed an issue in the taint tracking analysis where implicit reads were not allowed by default in sinks or additional taint steps that used flow states.
+
+## 0.3.5
+
+## 0.3.4
+
+### Deprecated APIs
+
+* Many classes/predicates/modules with upper-case acronyms in their name have been renamed to follow our style-guide. 
+  The old name still exists as a deprecated alias.
+
+### New Features
+
+* Added support for getting the link targets of global and namespace variables.
+* Added a `BlockAssignExpr` class, which models a `memcpy`-like operation used in compiler generated copy/move constructors and assignment operations.
+
+### Minor Analysis Improvements
+
+* All deprecated predicates/classes/modules that have been deprecated for over a year have been deleted.
+
 ## 0.3.3
 
 ### New Features

cpp/ql/lib/change-notes/released/0.3.4.md

@@ -0,0 +1,15 @@
+## 0.3.4
+
+### Deprecated APIs
+
+* Many classes/predicates/modules with upper-case acronyms in their name have been renamed to follow our style-guide. 
+  The old name still exists as a deprecated alias.
+
+### New Features
+
+* Added support for getting the link targets of global and namespace variables.
+* Added a `BlockAssignExpr` class, which models a `memcpy`-like operation used in compiler generated copy/move constructors and assignment operations.
+
+### Minor Analysis Improvements
+
+* All deprecated predicates/classes/modules that have been deprecated for over a year have been deleted.

cpp/ql/lib/change-notes/released/0.3.5.md

@@ -0,0 +1 @@
+## 0.3.5

cpp/ql/lib/change-notes/released/0.4.0.md

@@ -0,0 +1,14 @@
+## 0.4.0
+
+### Deprecated APIs
+
+* Some classes/modules with upper-case acronyms in their name have been renamed to follow our style-guide. 
+  The old name still exists as a deprecated alias.
+
+### New Features
+
+* Added subclasses of `BuiltInOperations` for `__is_same`, `__is_function`, `__is_layout_compatible`, `__is_pointer_interconvertible_base_of`, `__is_array`, `__array_rank`, `__array_extent`, `__is_arithmetic`, `__is_complete_type`, `__is_compound`, `__is_const`, `__is_floating_point`, `__is_fundamental`, `__is_integral`, `__is_lvalue_reference`, `__is_member_function_pointer`, `__is_member_object_pointer`, `__is_member_pointer`, `__is_object`, `__is_pointer`, `__is_reference`, `__is_rvalue_reference`, `__is_scalar`, `__is_signed`, `__is_unsigned`, `__is_void`, and `__is_volatile`.
+
+### Bug Fixes
+
+* Fixed an issue in the taint tracking analysis where implicit reads were not allowed by default in sinks or additional taint steps that used flow states.

cpp/ql/lib/change-notes/released/0.4.1.md

@@ -0,0 +1,3 @@
+## 0.4.1
+
+No user-facing changes.

cpp/ql/lib/codeql-pack.release.yml

@@ -1,2 +1,2 @@
 ---
-lastReleaseVersion: 0.3.3
+lastReleaseVersion: 0.4.1

cpp/ql/lib/experimental/semmle/code/cpp/dataflow/ProductFlow.qll

@@ -0,0 +1,301 @@
+import experimental.semmle.code.cpp.ir.dataflow.DataFlow
+import experimental.semmle.code.cpp.ir.dataflow.DataFlow2
+
+module ProductFlow {
+  abstract class Configuration extends string {
+    bindingset[this]
+    Configuration() { any() }
+
+    /**
+     * Holds if `(source1, source2)` is a relevant data flow source.
+     *
+     * `source1` and `source2` must belong to the same callable.
+     */
+    predicate isSourcePair(DataFlow::Node source1, DataFlow::Node source2) { none() }
+
+    /**
+     * Holds if `(source1, source2)` is a relevant data flow source with initial states `state1`
+     * and `state2`, respectively.
+     *
+     * `source1` and `source2` must belong to the same callable.
+     */
+    predicate isSourcePair(
+      DataFlow::Node source1, DataFlow::FlowState state1, DataFlow::Node source2,
+      DataFlow::FlowState state2
+    ) {
+      state1 = "" and
+      state2 = "" and
+      this.isSourcePair(source1, source2)
+    }
+
+    /**
+     * Holds if `(sink1, sink2)` is a relevant data flow sink.
+     *
+     * `sink1` and `sink2` must belong to the same callable.
+     */
+    predicate isSinkPair(DataFlow::Node sink1, DataFlow::Node sink2) { none() }
+
+    /**
+     * Holds if `(sink1, sink2)` is a relevant data flow sink with final states `state1`
+     * and `state2`, respectively.
+     *
+     * `sink1` and `sink2` must belong to the same callable.
+     */
+    predicate isSinkPair(
+      DataFlow::Node sink1, DataFlow::FlowState state1, DataFlow::Node sink2,
+      DataFlow::FlowState state2
+    ) {
+      state1 = "" and
+      state2 = "" and
+      this.isSinkPair(sink1, sink2)
+    }
+
+    /**
+     * Holds if data flow through `node` is prohibited through the first projection of the product
+     * dataflow graph when the flow state is `state`.
+     */
+    predicate isBarrier1(DataFlow::Node node, DataFlow::FlowState state) {
+      this.isBarrier1(node) and state = ""
+    }
+
+    /**
+     * Holds if data flow through `node` is prohibited through the second projection of the product
+     * dataflow graph when the flow state is `state`.
+     */
+    predicate isBarrier2(DataFlow::Node node, DataFlow::FlowState state) {
+      this.isBarrier2(node) and state = ""
+    }
+
+    /**
+     * Holds if data flow through `node` is prohibited through the first projection of the product
+     * dataflow graph.
+     */
+    predicate isBarrier1(DataFlow::Node node) { none() }
+
+    /**
+     * Holds if data flow through `node` is prohibited through the second projection of the product
+     * dataflow graph.
+     */
+    predicate isBarrier2(DataFlow::Node node) { none() }
+
+    /**
+     * Holds if data flow out of `node` is prohibited in the first projection of the product
+     * dataflow graph.
+     */
+    predicate isBarrierOut1(DataFlow::Node node) { none() }
+
+    /**
+     * Holds if data flow out of `node` is prohibited in the second projection of the product
+     * dataflow graph.
+     */
+    predicate isBarrierOut2(DataFlow::Node node) { none() }
+
+    /*
+     * Holds if data may flow from `node1` to `node2` in addition to the normal data-flow steps in
+     * the first projection of the product dataflow graph.
+     */
+
+    predicate isAdditionalFlowStep1(DataFlow::Node node1, DataFlow::Node node2) { none() }
+
+    /**
+     * Holds if data may flow from `node1` to `node2` in addition to the normal data-flow steps in
+     * the first projection of the product dataflow graph.
+     *
+     * This step is only applicable in `state1` and updates the flow state to `state2`.
+     */
+    predicate isAdditionalFlowStep1(
+      DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+      DataFlow::FlowState state2
+    ) {
+      state1 instanceof DataFlow::FlowStateEmpty and
+      state2 instanceof DataFlow::FlowStateEmpty and
+      this.isAdditionalFlowStep1(node1, node2)
+    }
+
+    /**
+     * Holds if data may flow from `node1` to `node2` in addition to the normal data-flow steps in
+     * the second projection of the product dataflow graph.
+     */
+    predicate isAdditionalFlowStep2(DataFlow::Node node1, DataFlow::Node node2) { none() }
+
+    /**
+     * Holds if data may flow from `node1` to `node2` in addition to the normal data-flow steps in
+     * the second projection of the product dataflow graph.
+     *
+     * This step is only applicable in `state1` and updates the flow state to `state2`.
+     */
+    predicate isAdditionalFlowStep2(
+      DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+      DataFlow::FlowState state2
+    ) {
+      state1 instanceof DataFlow::FlowStateEmpty and
+      state2 instanceof DataFlow::FlowStateEmpty and
+      this.isAdditionalFlowStep2(node1, node2)
+    }
+
+    /**
+     * Holds if data flow into `node` is prohibited in the first projection of the product
+     * dataflow graph.
+     */
+    predicate isBarrierIn1(DataFlow::Node node) { none() }
+
+    /**
+     * Holds if data flow into `node` is prohibited in the second projection of the product
+     * dataflow graph.
+     */
+    predicate isBarrierIn2(DataFlow::Node node) { none() }
+
+    predicate hasFlowPath(
+      DataFlow::PathNode source1, DataFlow2::PathNode source2, DataFlow::PathNode sink1,
+      DataFlow2::PathNode sink2
+    ) {
+      reachable(this, source1, source2, sink1, sink2)
+    }
+  }
+
+  private import Internal
+
+  module Internal {
+    class Conf1 extends DataFlow::Configuration {
+      Conf1() { this = "Conf1" }
+
+      override predicate isSource(DataFlow::Node source, DataFlow::FlowState state) {
+        exists(Configuration conf | conf.isSourcePair(source, state, _, _))
+      }
+
+      override predicate isSink(DataFlow::Node sink, DataFlow::FlowState state) {
+        exists(Configuration conf | conf.isSinkPair(sink, state, _, _))
+      }
+
+      override predicate isBarrier(DataFlow::Node node, DataFlow::FlowState state) {
+        exists(Configuration conf | conf.isBarrier1(node, state))
+      }
+
+      override predicate isBarrierOut(DataFlow::Node node) {
+        exists(Configuration conf | conf.isBarrierOut1(node))
+      }
+
+      override predicate isAdditionalFlowStep(
+        DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+        DataFlow::FlowState state2
+      ) {
+        exists(Configuration conf | conf.isAdditionalFlowStep1(node1, state1, node2, state2))
+      }
+
+      override predicate isBarrierIn(DataFlow::Node node) {
+        exists(Configuration conf | conf.isBarrierIn1(node))
+      }
+    }
+
+    class Conf2 extends DataFlow2::Configuration {
+      Conf2() { this = "Conf2" }
+
+      override predicate isSource(DataFlow::Node source, DataFlow::FlowState state) {
+        exists(Configuration conf, DataFlow::PathNode source1 |
+          conf.isSourcePair(source1.getNode(), source1.getState(), source, state) and
+          any(Conf1 c).hasFlowPath(source1, _)
+        )
+      }
+
+      override predicate isSink(DataFlow::Node sink, DataFlow::FlowState state) {
+        exists(Configuration conf, DataFlow::PathNode sink1 |
+          conf.isSinkPair(sink1.getNode(), sink1.getState(), sink, state) and
+          any(Conf1 c).hasFlowPath(_, sink1)
+        )
+      }
+
+      override predicate isBarrier(DataFlow::Node node, DataFlow::FlowState state) {
+        exists(Configuration conf | conf.isBarrier2(node, state))
+      }
+
+      override predicate isBarrierOut(DataFlow::Node node) {
+        exists(Configuration conf | conf.isBarrierOut2(node))
+      }
+
+      override predicate isAdditionalFlowStep(
+        DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+        DataFlow::FlowState state2
+      ) {
+        exists(Configuration conf | conf.isAdditionalFlowStep2(node1, state1, node2, state2))
+      }
+
+      override predicate isBarrierIn(DataFlow::Node node) {
+        exists(Configuration conf | conf.isBarrierIn2(node))
+      }
+    }
+  }
+
+  pragma[nomagic]
+  private predicate reachableInterprocEntry(
+    Configuration conf, DataFlow::PathNode source1, DataFlow2::PathNode source2,
+    DataFlow::PathNode node1, DataFlow2::PathNode node2
+  ) {
+    conf.isSourcePair(node1.getNode(), node1.getState(), node2.getNode(), node2.getState()) and
+    node1 = source1 and
+    node2 = source2
+    or
+    exists(
+      DataFlow::PathNode midEntry1, DataFlow2::PathNode midEntry2, DataFlow::PathNode midExit1,
+      DataFlow2::PathNode midExit2
+    |
+      reachableInterprocEntry(conf, source1, source2, midEntry1, midEntry2) and
+      interprocEdgePair(midExit1, midExit2, node1, node2) and
+      localPathStep1*(midEntry1, midExit1) and
+      localPathStep2*(midEntry2, midExit2)
+    )
+  }
+
+  private predicate localPathStep1(DataFlow::PathNode pred, DataFlow::PathNode succ) {
+    DataFlow::PathGraph::edges(pred, succ) and
+    pragma[only_bind_out](pred.getNode().getEnclosingCallable()) =
+      pragma[only_bind_out](succ.getNode().getEnclosingCallable())
+  }
+
+  private predicate localPathStep2(DataFlow2::PathNode pred, DataFlow2::PathNode succ) {
+    DataFlow2::PathGraph::edges(pred, succ) and
+    pragma[only_bind_out](pred.getNode().getEnclosingCallable()) =
+      pragma[only_bind_out](succ.getNode().getEnclosingCallable())
+  }
+
+  pragma[nomagic]
+  private predicate interprocEdge1(
+    Declaration predDecl, Declaration succDecl, DataFlow::PathNode pred1, DataFlow::PathNode succ1
+  ) {
+    DataFlow::PathGraph::edges(pred1, succ1) and
+    predDecl != succDecl and
+    pred1.getNode().getEnclosingCallable() = predDecl and
+    succ1.getNode().getEnclosingCallable() = succDecl
+  }
+
+  pragma[nomagic]
+  private predicate interprocEdge2(
+    Declaration predDecl, Declaration succDecl, DataFlow2::PathNode pred2, DataFlow2::PathNode succ2
+  ) {
+    DataFlow2::PathGraph::edges(pred2, succ2) and
+    predDecl != succDecl and
+    pred2.getNode().getEnclosingCallable() = predDecl and
+    succ2.getNode().getEnclosingCallable() = succDecl
+  }
+
+  private predicate interprocEdgePair(
+    DataFlow::PathNode pred1, DataFlow2::PathNode pred2, DataFlow::PathNode succ1,
+    DataFlow2::PathNode succ2
+  ) {
+    exists(Declaration predDecl, Declaration succDecl |
+      interprocEdge1(predDecl, succDecl, pred1, succ1) and
+      interprocEdge2(predDecl, succDecl, pred2, succ2)
+    )
+  }
+
+  private predicate reachable(
+    Configuration conf, DataFlow::PathNode source1, DataFlow2::PathNode source2,
+    DataFlow::PathNode sink1, DataFlow2::PathNode sink2
+  ) {
+    exists(DataFlow::PathNode mid1, DataFlow2::PathNode mid2 |
+      reachableInterprocEntry(conf, source1, source2, mid1, mid2) and
+      conf.isSinkPair(sink1.getNode(), sink1.getState(), sink2.getNode(), sink2.getState()) and
+      localPathStep1*(mid1, sink1) and
+      localPathStep2*(mid2, sink2)
+    )
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/DataFlow.qll

@@ -0,0 +1,26 @@
+/**
+ * Provides a library for local (intra-procedural) and global (inter-procedural)
+ * data flow analysis: deciding whether data can flow from a _source_ to a
+ * _sink_. This library differs from the one in `semmle.code.cpp.dataflow` in that
+ * this library uses the IR (Intermediate Representation) library, which provides
+ * a more precise semantic representation of the program, whereas the other dataflow
+ * library uses the more syntax-oriented ASTs. This library should provide more accurate
+ * results than the AST-based library in most scenarios.
+ *
+ * Unless configured otherwise, _flow_ means that the exact value of
+ * the source may reach the sink. We do not track flow across pointer
+ * dereferences or array indexing.
+ *
+ * To use global (interprocedural) data flow, extend the class
+ * `DataFlow::Configuration` as documented on that class. To use local
+ * (intraprocedural) data flow between expressions, call
+ * `DataFlow::localExprFlow`. For more general cases of local data flow, call
+ * `DataFlow::localFlow` or `DataFlow::localFlowStep` with arguments of type
+ * `DataFlow::Node`.
+ */
+
+import cpp
+
+module DataFlow {
+  import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowImpl
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/DataFlow2.qll

@@ -0,0 +1,16 @@
+/**
+ * Provides a `DataFlow2` module, which is a copy of the `DataFlow` module. Use
+ * this class when data-flow configurations must depend on each other. Two
+ * classes extending `DataFlow::Configuration` should never depend on each
+ * other, but one of them should instead depend on a
+ * `DataFlow2::Configuration`, a `DataFlow3::Configuration`, or a
+ * `DataFlow4::Configuration`.
+ *
+ * See `semmle.code.cpp.ir.dataflow.DataFlow` for the full documentation.
+ */
+
+import cpp
+
+module DataFlow2 {
+  import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowImpl2
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/DataFlow3.qll

@@ -0,0 +1,16 @@
+/**
+ * Provides a `DataFlow3` module, which is a copy of the `DataFlow` module. Use
+ * this class when data-flow configurations must depend on each other. Two
+ * classes extending `DataFlow::Configuration` should never depend on each
+ * other, but one of them should instead depend on a
+ * `DataFlow2::Configuration`, a `DataFlow3::Configuration`, or a
+ * `DataFlow4::Configuration`.
+ *
+ * See `semmle.code.cpp.ir.dataflow.DataFlow` for the full documentation.
+ */
+
+import cpp
+
+module DataFlow3 {
+  import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowImpl3
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/DataFlow4.qll

@@ -0,0 +1,16 @@
+/**
+ * Provides a `DataFlow4` module, which is a copy of the `DataFlow` module. Use
+ * this class when data-flow configurations must depend on each other. Two
+ * classes extending `DataFlow::Configuration` should never depend on each
+ * other, but one of them should instead depend on a
+ * `DataFlow2::Configuration`, a `DataFlow3::Configuration`, or a
+ * `DataFlow4::Configuration`.
+ *
+ * See `semmle.code.cpp.ir.dataflow.DataFlow` for the full documentation.
+ */
+
+import cpp
+
+module DataFlow4 {
+  import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowImpl4
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/ResolveCall.qll

@@ -0,0 +1,23 @@
+/**
+ * Provides a predicate for non-contextual virtual dispatch and function
+ * pointer resolution.
+ */
+
+import cpp
+private import semmle.code.cpp.ir.ValueNumbering
+private import internal.DataFlowDispatch
+private import semmle.code.cpp.ir.IR
+
+/**
+ * Resolve potential target function(s) for `call`.
+ *
+ * If `call` is a call through a function pointer (`ExprCall`) or its target is
+ * a virtual member function, simple data flow analysis is performed in order
+ * to identify the possible target(s).
+ */
+Function resolveCall(Call call) {
+  exists(CallInstruction callInstruction |
+    callInstruction.getAst() = call and
+    result = viableCallable(callInstruction)
+  )
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/TaintTracking.qll

@@ -0,0 +1,23 @@
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) taint-tracking analyses.
+ *
+ * We define _taint propagation_ informally to mean that a substantial part of
+ * the information from the source is preserved at the sink. For example, taint
+ * propagates from `x` to `x + 100`, but it does not propagate from `x` to `x >
+ * 100` since we consider a single bit of information to be too little.
+ *
+ * To use global (interprocedural) taint tracking, extend the class
+ * `TaintTracking::Configuration` as documented on that class. To use local
+ * (intraprocedural) taint tracking between expressions, call
+ * `TaintTracking::localExprTaint`. For more general cases of local taint
+ * tracking, call `TaintTracking::localTaint` or
+ * `TaintTracking::localTaintStep` with arguments of type `DataFlow::Node`.
+ */
+
+import semmle.code.cpp.ir.dataflow.DataFlow
+import semmle.code.cpp.ir.dataflow.DataFlow2
+
+module TaintTracking {
+  import experimental.semmle.code.cpp.ir.dataflow.internal.tainttracking1.TaintTrackingImpl
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/TaintTracking2.qll

@@ -0,0 +1,15 @@
+/**
+ * Provides a `TaintTracking2` module, which is a copy of the `TaintTracking`
+ * module. Use this class when data-flow configurations or taint-tracking
+ * configurations must depend on each other. Two classes extending
+ * `DataFlow::Configuration` should never depend on each other, but one of them
+ * should instead depend on a `DataFlow2::Configuration`, a
+ * `DataFlow3::Configuration`, or a `DataFlow4::Configuration`. The
+ * `TaintTracking::Configuration` class extends `DataFlow::Configuration`, and
+ * `TaintTracking2::Configuration` extends `DataFlow2::Configuration`.
+ *
+ * See `semmle.code.cpp.ir.dataflow.TaintTracking` for the full documentation.
+ */
+module TaintTracking2 {
+  import experimental.semmle.code.cpp.ir.dataflow.internal.tainttracking2.TaintTrackingImpl
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/TaintTracking3.qll

@@ -0,0 +1,15 @@
+/**
+ * Provides a `TaintTracking3` module, which is a copy of the `TaintTracking`
+ * module. Use this class when data-flow configurations or taint-tracking
+ * configurations must depend on each other. Two classes extending
+ * `DataFlow::Configuration` should never depend on each other, but one of them
+ * should instead depend on a `DataFlow2::Configuration`, a
+ * `DataFlow3::Configuration`, or a `DataFlow4::Configuration`. The
+ * `TaintTracking::Configuration` class extends `DataFlow::Configuration`, and
+ * `TaintTracking2::Configuration` extends `DataFlow2::Configuration`.
+ *
+ * See `semmle.code.cpp.ir.dataflow.TaintTracking` for the full documentation.
+ */
+module TaintTracking3 {
+  import experimental.semmle.code.cpp.ir.dataflow.internal.tainttracking3.TaintTrackingImpl
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowDispatch.qll

@@ -0,0 +1,273 @@
+private import cpp
+private import semmle.code.cpp.ir.IR
+private import experimental.semmle.code.cpp.ir.dataflow.DataFlow
+private import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowPrivate
+private import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
+private import DataFlowImplCommon as DataFlowImplCommon
+
+/**
+ * Gets a function that might be called by `call`.
+ */
+cached
+Function viableCallable(CallInstruction call) {
+  DataFlowImplCommon::forceCachingInSameStage() and
+  result = call.getStaticCallTarget()
+  or
+  // If the target of the call does not have a body in the snapshot, it might
+  // be because the target is just a header declaration, and the real target
+  // will be determined at run time when the caller and callee are linked
+  // together by the operating system's dynamic linker. In case a _unique_
+  // function with the right signature is present in the database, we return
+  // that as a potential callee.
+  exists(string qualifiedName, int nparams |
+    callSignatureWithoutBody(qualifiedName, nparams, call) and
+    functionSignatureWithBody(qualifiedName, nparams, result) and
+    strictcount(Function other | functionSignatureWithBody(qualifiedName, nparams, other)) = 1
+  )
+  or
+  // Virtual dispatch
+  result = call.(VirtualDispatch::DataSensitiveCall).resolve()
+}
+
+/**
+ * Provides virtual dispatch support compatible with the original
+ * implementation of `semmle.code.cpp.security.TaintTracking`.
+ */
+private module VirtualDispatch {
+  /** A call that may dispatch differently depending on the qualifier value. */
+  abstract class DataSensitiveCall extends DataFlowCall {
+    /**
+     * Gets the node whose value determines the target of this call. This node
+     * could be the qualifier of a virtual dispatch or the function-pointer
+     * expression in a call to a function pointer. What they have in common is
+     * that we need to find out which data flows there, and then it's up to the
+     * `resolve` predicate to stitch that information together and resolve the
+     * call.
+     */
+    abstract DataFlow::Node getDispatchValue();
+
+    /** Gets a candidate target for this call. */
+    abstract Function resolve();
+
+    /**
+     * Whether `src` can flow to this call.
+     *
+     * Searches backwards from `getDispatchValue()` to `src`. The `allowFromArg`
+     * parameter is true when the search is allowed to continue backwards into
+     * a parameter; non-recursive callers should pass `_` for `allowFromArg`.
+     */
+    predicate flowsFrom(DataFlow::Node src, boolean allowFromArg) {
+      src = this.getDispatchValue() and allowFromArg = true
+      or
+      exists(DataFlow::Node other, boolean allowOtherFromArg |
+        this.flowsFrom(other, allowOtherFromArg)
+      |
+        // Call argument
+        exists(DataFlowCall call, Position i |
+          other
+              .(DataFlow::ParameterNode)
+              .isParameterOf(pragma[only_bind_into](call).getStaticCallTarget(), i) and
+          src.(ArgumentNode).argumentOf(call, pragma[only_bind_into](pragma[only_bind_out](i)))
+        ) and
+        allowOtherFromArg = true and
+        allowFromArg = true
+        or
+        // Call return
+        exists(DataFlowCall call, ReturnKind returnKind |
+          other = getAnOutNode(call, returnKind) and
+          returnNodeWithKindAndEnclosingCallable(src, returnKind, call.getStaticCallTarget())
+        ) and
+        allowFromArg = false
+        or
+        // Local flow
+        DataFlow::localFlowStep(src, other) and
+        allowFromArg = allowOtherFromArg
+        or
+        // Flow from global variable to load.
+        exists(LoadInstruction load, GlobalOrNamespaceVariable var |
+          var = src.asVariable() and
+          other.asInstruction() = load and
+          addressOfGlobal(load.getSourceAddress(), var) and
+          // The `allowFromArg` concept doesn't play a role when `src` is a
+          // global variable, so we just set it to a single arbitrary value for
+          // performance.
+          allowFromArg = true
+        )
+        or
+        // Flow from store to global variable.
+        exists(StoreInstruction store, GlobalOrNamespaceVariable var |
+          var = other.asVariable() and
+          store = src.asInstruction() and
+          storeIntoGlobal(store, var) and
+          // Setting `allowFromArg` to `true` like in the base case means we
+          // treat a store to a global variable like the dispatch itself: flow
+          // may come from anywhere.
+          allowFromArg = true
+        )
+      )
+    }
+  }
+
+  pragma[noinline]
+  private predicate storeIntoGlobal(StoreInstruction store, GlobalOrNamespaceVariable var) {
+    addressOfGlobal(store.getDestinationAddress(), var)
+  }
+
+  /** Holds if `addressInstr` is an instruction that produces the address of `var`. */
+  private predicate addressOfGlobal(Instruction addressInstr, GlobalOrNamespaceVariable var) {
+    // Access directly to the global variable
+    addressInstr.(VariableAddressInstruction).getAstVariable() = var
+    or
+    // Access to a field on a global union
+    exists(FieldAddressInstruction fa |
+      fa = addressInstr and
+      fa.getObjectAddress().(VariableAddressInstruction).getAstVariable() = var and
+      fa.getField().getDeclaringType() instanceof Union
+    )
+  }
+
+  /**
+   * A ReturnNode with its ReturnKind and its enclosing callable.
+   *
+   * Used to fix a join ordering issue in flowsFrom.
+   */
+  pragma[noinline]
+  private predicate returnNodeWithKindAndEnclosingCallable(
+    ReturnNode node, ReturnKind kind, DataFlowCallable callable
+  ) {
+    node.getKind() = kind and
+    node.getEnclosingCallable() = callable
+  }
+
+  /** Call through a function pointer. */
+  private class DataSensitiveExprCall extends DataSensitiveCall {
+    DataSensitiveExprCall() { not exists(this.getStaticCallTarget()) }
+
+    override DataFlow::Node getDispatchValue() { result.asInstruction() = this.getCallTarget() }
+
+    override Function resolve() {
+      exists(FunctionInstruction fi |
+        this.flowsFrom(DataFlow::instructionNode(fi), _) and
+        result = fi.getFunctionSymbol()
+      ) and
+      (
+        this.getNumberOfArguments() <= result.getEffectiveNumberOfParameters() and
+        this.getNumberOfArguments() >= result.getEffectiveNumberOfParameters()
+        or
+        result.isVarargs()
+      )
+    }
+  }
+
+  /** Call to a virtual function. */
+  private class DataSensitiveOverriddenFunctionCall extends DataSensitiveCall {
+    DataSensitiveOverriddenFunctionCall() {
+      exists(this.getStaticCallTarget().(VirtualFunction).getAnOverridingFunction())
+    }
+
+    override DataFlow::Node getDispatchValue() { result.asInstruction() = this.getThisArgument() }
+
+    override MemberFunction resolve() {
+      exists(Class overridingClass |
+        this.overrideMayAffectCall(overridingClass, result) and
+        this.hasFlowFromCastFrom(overridingClass)
+      )
+    }
+
+    /**
+     * Holds if `this` is a virtual function call whose static target is
+     * overridden by `overridingFunction` in `overridingClass`.
+     */
+    pragma[noinline]
+    private predicate overrideMayAffectCall(Class overridingClass, MemberFunction overridingFunction) {
+      overridingFunction.getAnOverriddenFunction+() = this.getStaticCallTarget().(VirtualFunction) and
+      overridingFunction.getDeclaringType() = overridingClass
+    }
+
+    /**
+     * Holds if the qualifier of `this` has flow from an upcast from
+     * `derivedClass`.
+     */
+    pragma[noinline]
+    private predicate hasFlowFromCastFrom(Class derivedClass) {
+      exists(ConvertToBaseInstruction toBase |
+        this.flowsFrom(DataFlow::instructionNode(toBase), _) and
+        derivedClass = toBase.getDerivedClass()
+      )
+    }
+  }
+}
+
+/**
+ * Holds if `f` is a function with a body that has name `qualifiedName` and
+ * `nparams` parameter count. See `functionSignature`.
+ */
+private predicate functionSignatureWithBody(string qualifiedName, int nparams, Function f) {
+  functionSignature(f, qualifiedName, nparams) and
+  exists(f.getBlock())
+}
+
+/**
+ * Holds if the target of `call` is a function _with no definition_ that has
+ * name `qualifiedName` and `nparams` parameter count. See `functionSignature`.
+ */
+pragma[noinline]
+private predicate callSignatureWithoutBody(string qualifiedName, int nparams, CallInstruction call) {
+  exists(Function target |
+    target = call.getStaticCallTarget() and
+    not exists(target.getBlock()) and
+    functionSignature(target, qualifiedName, nparams)
+  )
+}
+
+/**
+ * Holds if `f` has name `qualifiedName` and `nparams` parameter count. This is
+ * an approximation of its signature for the purpose of matching functions that
+ * might be the same across link targets.
+ */
+private predicate functionSignature(Function f, string qualifiedName, int nparams) {
+  qualifiedName = f.getQualifiedName() and
+  nparams = f.getNumberOfParameters() and
+  not f.isStatic()
+}
+
+/**
+ * Holds if the set of viable implementations that can be called by `call`
+ * might be improved by knowing the call context.
+ */
+predicate mayBenefitFromCallContext(CallInstruction call, Function f) {
+  mayBenefitFromCallContext(call, f, _)
+}
+
+/**
+ * Holds if `call` is a call through a function pointer, and the pointer
+ * value is given as the `arg`'th argument to `f`.
+ */
+private predicate mayBenefitFromCallContext(
+  VirtualDispatch::DataSensitiveCall call, Function f, int arg
+) {
+  f = pragma[only_bind_out](call).getEnclosingCallable() and
+  exists(InitializeParameterInstruction init |
+    not exists(call.getStaticCallTarget()) and
+    init.getEnclosingFunction() = f and
+    call.flowsFrom(DataFlow::instructionNode(init), _) and
+    init.getParameter().getIndex() = arg
+  )
+}
+
+/**
+ * Gets a viable dispatch target of `call` in the context `ctx`. This is
+ * restricted to those `call`s for which a context might make a difference.
+ */
+Function viableImplInCallContext(CallInstruction call, CallInstruction ctx) {
+  result = viableCallable(call) and
+  exists(int i, Function f |
+    mayBenefitFromCallContext(pragma[only_bind_into](call), f, i) and
+    f = ctx.getStaticCallTarget() and
+    result = ctx.getArgument(i).getUnconvertedResultExpression().(FunctionAccess).getTarget()
+  )
+}
+
+/** Holds if arguments at position `apos` match parameters at position `ppos`. */
+pragma[inline]
+predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) { ppos = apos }

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll

@@ -163,7 +163,9 @@ abstract class Configuration extends string {
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
    */
-  predicate hasFlowTo(Node sink) { this.hasFlow(_, sink) }
+  predicate hasFlowTo(Node sink) {
+    sink = any(PathNodeSink n | this = n.getConfiguration()).getNodeEx().asNode()
+  }
 
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
@@ -558,13 +560,16 @@ private predicate expectsContentEx(NodeEx n, Content c) {
 pragma[nomagic]
 private predicate notExpectsContent(NodeEx n) { not expectsContentCached(n.asNode(), _) }
 
+pragma[nomagic]
+private predicate hasReadStep(Content c, Configuration config) { read(_, c, _, config) }
+
 pragma[nomagic]
 private predicate store(
   NodeEx node1, TypedContent tc, NodeEx node2, DataFlowType contentType, Configuration config
 ) {
   store(pragma[only_bind_into](node1.asNode()), tc, pragma[only_bind_into](node2.asNode()),
     contentType) and
-  read(_, tc.getContent(), _, config) and
+  hasReadStep(tc.getContent(), config) and
   stepFilter(node1, node2, config)
 }
 
@@ -598,13 +603,9 @@ private predicate hasSinkCallCtx(Configuration config) {
 }
 
 private module Stage1 implements StageSig {
-  class ApApprox = Unit;
-
   class Ap = Unit;
 
-  class ApOption = Unit;
-
-  class Cc = boolean;
+  private class Cc = boolean;
 
   /* Begin: Stage 1 logic. */
   /**
@@ -613,7 +614,7 @@ private module Stage1 implements StageSig {
    * The Boolean `cc` records whether the node is reached through an
    * argument in a call.
    */
-  predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
+  private predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
     sourceNode(node, _, config) and
     if hasSourceCallCtx(config) then cc = true else cc = false
     or
@@ -753,7 +754,7 @@ private module Stage1 implements StageSig {
    * the enclosing callable in order to reach a sink.
    */
   pragma[nomagic]
-  predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
+  private predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
     revFlow0(node, toReturn, config) and
     fwdFlow(node, config)
   }
@@ -837,13 +838,13 @@ private module Stage1 implements StageSig {
    * by `revFlow`.
    */
   pragma[nomagic]
-  predicate revFlowIsReadAndStored(Content c, Configuration conf) {
+  additional predicate revFlowIsReadAndStored(Content c, Configuration conf) {
     revFlowConsCand(c, conf) and
     revFlowStore(c, _, _, conf)
   }
 
   pragma[nomagic]
-  predicate viableReturnPosOutNodeCandFwd1(
+  additional predicate viableReturnPosOutNodeCandFwd1(
     DataFlowCall call, ReturnPosition pos, NodeEx out, Configuration config
   ) {
     fwdFlowReturnPosition(pos, _, config) and
@@ -859,7 +860,7 @@ private module Stage1 implements StageSig {
   }
 
   pragma[nomagic]
-  predicate viableParamArgNodeCandFwd1(
+  additional predicate viableParamArgNodeCandFwd1(
     DataFlowCall call, ParamNodeEx p, ArgNodeEx arg, Configuration config
   ) {
     viableParamArgEx(call, p, arg) and
@@ -906,7 +907,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate revFlowState(FlowState state, Configuration config) {
+  additional predicate revFlowState(FlowState state, Configuration config) {
     exists(NodeEx node |
       sinkNode(node, state, config) and
       revFlow(node, _, pragma[only_bind_into](config)) and
@@ -998,7 +999,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate stats(
+  additional predicate stats(
     boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
   ) {
     fwd = true and
@@ -1259,7 +1260,7 @@ private module MkStage<StageSig PrevStage> {
      * argument.
      */
     pragma[nomagic]
-    predicate fwdFlow(
+    additional predicate fwdFlow(
       NodeEx node, FlowState state, Cc cc, ApOption argAp, Ap ap, Configuration config
     ) {
       fwdFlow0(node, state, cc, argAp, ap, config) and
@@ -1483,7 +1484,7 @@ private module MkStage<StageSig PrevStage> {
      * the access path of the returned value.
      */
     pragma[nomagic]
-    predicate revFlow(
+    additional predicate revFlow(
       NodeEx node, FlowState state, boolean toReturn, ApOption returnAp, Ap ap, Configuration config
     ) {
       revFlow0(node, state, toReturn, returnAp, ap, config) and
@@ -1661,7 +1662,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate revFlow(NodeEx node, FlowState state, Configuration config) {
+    additional predicate revFlow(NodeEx node, FlowState state, Configuration config) {
       revFlow(node, state, _, _, _, config)
     }
 
@@ -1674,11 +1675,13 @@ private module MkStage<StageSig PrevStage> {
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, Configuration config) { revFlow(node, _, _, _, _, config) }
+    additional predicate revFlowAlias(NodeEx node, Configuration config) {
+      revFlow(node, _, _, _, _, config)
+    }
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
+    additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
       revFlow(node, state, ap, config)
     }
 
@@ -1699,7 +1702,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate consCand(TypedContent tc, Ap ap, Configuration config) {
+    additional predicate consCand(TypedContent tc, Ap ap, Configuration config) {
       revConsCand(tc, ap, config) and
       validAp(ap, config)
     }
@@ -1741,7 +1744,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate stats(
+    additional predicate stats(
       boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
     ) {
       fwd = true and
@@ -2926,12 +2929,17 @@ abstract private class PathNodeImpl extends PathNode {
     result = this.getASuccessorImpl()
   }
 
-  final PathNodeImpl getANonHiddenSuccessor() {
-    result = this.getASuccessorImpl().getASuccessorIfHidden*() and
-    not this.isHidden() and
+  pragma[nomagic]
+  private PathNodeImpl getANonHiddenSuccessor0() {
+    result = this.getASuccessorIfHidden*() and
     not result.isHidden()
   }
 
+  final PathNodeImpl getANonHiddenSuccessor() {
+    result = this.getASuccessorImpl().getANonHiddenSuccessor0() and
+    not this.isHidden()
+  }
+
   abstract NodeEx getNodeEx();
 
   predicate isHidden() {
@@ -3061,7 +3069,7 @@ private class PathNodeMid extends PathNodeImpl, TPathNodeMid {
       else cc instanceof CallContextAny
     ) and
     sc instanceof SummaryCtxNone and
-    ap instanceof AccessPathNil
+    ap = TAccessPathNil(node.getDataFlowType())
   }
 
   predicate isAtSink() {

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImplConsistency.qll

@@ -0,0 +1,235 @@
+/**
+ * Provides consistency queries for checking invariants in the language-specific
+ * data-flow classes and predicates.
+ */
+
+private import DataFlowImplSpecific::Private
+private import DataFlowImplSpecific::Public
+private import tainttracking1.TaintTrackingParameter::Private
+private import tainttracking1.TaintTrackingParameter::Public
+
+module Consistency {
+  private newtype TConsistencyConfiguration = MkConsistencyConfiguration()
+
+  /** A class for configuring the consistency queries. */
+  class ConsistencyConfiguration extends TConsistencyConfiguration {
+    string toString() { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `uniqueEnclosingCallable`. */
+    predicate uniqueEnclosingCallableExclude(Node n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `uniqueNodeLocation`. */
+    predicate uniqueNodeLocationExclude(Node n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `missingLocation`. */
+    predicate missingLocationExclude(Node n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `postWithInFlow`. */
+    predicate postWithInFlowExclude(Node n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `argHasPostUpdate`. */
+    predicate argHasPostUpdateExclude(ArgumentNode n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `reverseRead`. */
+    predicate reverseReadExclude(Node n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `postHasUniquePre`. */
+    predicate postHasUniquePreExclude(PostUpdateNode n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `uniquePostUpdate`. */
+    predicate uniquePostUpdateExclude(Node n) { none() }
+
+    /** Holds if `(call, ctx)` should be excluded from the consistency test `viableImplInCallContextTooLargeExclude`. */
+    predicate viableImplInCallContextTooLargeExclude(
+      DataFlowCall call, DataFlowCall ctx, DataFlowCallable callable
+    ) {
+      none()
+    }
+  }
+
+  private class RelevantNode extends Node {
+    RelevantNode() {
+      this instanceof ArgumentNode or
+      this instanceof ParameterNode or
+      this instanceof ReturnNode or
+      this = getAnOutNode(_, _) or
+      simpleLocalFlowStep(this, _) or
+      simpleLocalFlowStep(_, this) or
+      jumpStep(this, _) or
+      jumpStep(_, this) or
+      storeStep(this, _, _) or
+      storeStep(_, _, this) or
+      readStep(this, _, _) or
+      readStep(_, _, this) or
+      defaultAdditionalTaintStep(this, _) or
+      defaultAdditionalTaintStep(_, this)
+    }
+  }
+
+  query predicate uniqueEnclosingCallable(Node n, string msg) {
+    exists(int c |
+      n instanceof RelevantNode and
+      c = count(nodeGetEnclosingCallable(n)) and
+      c != 1 and
+      not any(ConsistencyConfiguration conf).uniqueEnclosingCallableExclude(n) and
+      msg = "Node should have one enclosing callable but has " + c + "."
+    )
+  }
+
+  query predicate uniqueType(Node n, string msg) {
+    exists(int c |
+      n instanceof RelevantNode and
+      c = count(getNodeType(n)) and
+      c != 1 and
+      msg = "Node should have one type but has " + c + "."
+    )
+  }
+
+  query predicate uniqueNodeLocation(Node n, string msg) {
+    exists(int c |
+      c =
+        count(string filepath, int startline, int startcolumn, int endline, int endcolumn |
+          n.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
+        ) and
+      c != 1 and
+      not any(ConsistencyConfiguration conf).uniqueNodeLocationExclude(n) and
+      msg = "Node should have one location but has " + c + "."
+    )
+  }
+
+  query predicate missingLocation(string msg) {
+    exists(int c |
+      c =
+        strictcount(Node n |
+          not exists(string filepath, int startline, int startcolumn, int endline, int endcolumn |
+            n.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
+          ) and
+          not any(ConsistencyConfiguration conf).missingLocationExclude(n)
+        ) and
+      msg = "Nodes without location: " + c
+    )
+  }
+
+  query predicate uniqueNodeToString(Node n, string msg) {
+    exists(int c |
+      c = count(n.toString()) and
+      c != 1 and
+      msg = "Node should have one toString but has " + c + "."
+    )
+  }
+
+  query predicate missingToString(string msg) {
+    exists(int c |
+      c = strictcount(Node n | not exists(n.toString())) and
+      msg = "Nodes without toString: " + c
+    )
+  }
+
+  query predicate parameterCallable(ParameterNode p, string msg) {
+    exists(DataFlowCallable c | isParameterNode(p, c, _) and c != nodeGetEnclosingCallable(p)) and
+    msg = "Callable mismatch for parameter."
+  }
+
+  query predicate localFlowIsLocal(Node n1, Node n2, string msg) {
+    simpleLocalFlowStep(n1, n2) and
+    nodeGetEnclosingCallable(n1) != nodeGetEnclosingCallable(n2) and
+    msg = "Local flow step does not preserve enclosing callable."
+  }
+
+  private DataFlowType typeRepr() { result = getNodeType(_) }
+
+  query predicate compatibleTypesReflexive(DataFlowType t, string msg) {
+    t = typeRepr() and
+    not compatibleTypes(t, t) and
+    msg = "Type compatibility predicate is not reflexive."
+  }
+
+  query predicate unreachableNodeCCtx(Node n, DataFlowCall call, string msg) {
+    isUnreachableInCall(n, call) and
+    exists(DataFlowCallable c |
+      c = nodeGetEnclosingCallable(n) and
+      not viableCallable(call) = c
+    ) and
+    msg = "Call context for isUnreachableInCall is inconsistent with call graph."
+  }
+
+  query predicate localCallNodes(DataFlowCall call, Node n, string msg) {
+    (
+      n = getAnOutNode(call, _) and
+      msg = "OutNode and call does not share enclosing callable."
+      or
+      n.(ArgumentNode).argumentOf(call, _) and
+      msg = "ArgumentNode and call does not share enclosing callable."
+    ) and
+    nodeGetEnclosingCallable(n) != call.getEnclosingCallable()
+  }
+
+  // This predicate helps the compiler forget that in some languages
+  // it is impossible for a result of `getPreUpdateNode` to be an
+  // instance of `PostUpdateNode`.
+  private Node getPre(PostUpdateNode n) {
+    result = n.getPreUpdateNode()
+    or
+    none()
+  }
+
+  query predicate postIsNotPre(PostUpdateNode n, string msg) {
+    getPre(n) = n and
+    msg = "PostUpdateNode should not equal its pre-update node."
+  }
+
+  query predicate postHasUniquePre(PostUpdateNode n, string msg) {
+    not any(ConsistencyConfiguration conf).postHasUniquePreExclude(n) and
+    exists(int c |
+      c = count(n.getPreUpdateNode()) and
+      c != 1 and
+      msg = "PostUpdateNode should have one pre-update node but has " + c + "."
+    )
+  }
+
+  query predicate uniquePostUpdate(Node n, string msg) {
+    not any(ConsistencyConfiguration conf).uniquePostUpdateExclude(n) and
+    1 < strictcount(PostUpdateNode post | post.getPreUpdateNode() = n) and
+    msg = "Node has multiple PostUpdateNodes."
+  }
+
+  query predicate postIsInSameCallable(PostUpdateNode n, string msg) {
+    nodeGetEnclosingCallable(n) != nodeGetEnclosingCallable(n.getPreUpdateNode()) and
+    msg = "PostUpdateNode does not share callable with its pre-update node."
+  }
+
+  private predicate hasPost(Node n) { exists(PostUpdateNode post | post.getPreUpdateNode() = n) }
+
+  query predicate reverseRead(Node n, string msg) {
+    exists(Node n2 | readStep(n, _, n2) and hasPost(n2) and not hasPost(n)) and
+    not any(ConsistencyConfiguration conf).reverseReadExclude(n) and
+    msg = "Origin of readStep is missing a PostUpdateNode."
+  }
+
+  query predicate argHasPostUpdate(ArgumentNode n, string msg) {
+    not hasPost(n) and
+    not any(ConsistencyConfiguration c).argHasPostUpdateExclude(n) and
+    msg = "ArgumentNode is missing PostUpdateNode."
+  }
+
+  // This predicate helps the compiler forget that in some languages
+  // it is impossible for a `PostUpdateNode` to be the target of
+  // `simpleLocalFlowStep`.
+  private predicate isPostUpdateNode(Node n) { n instanceof PostUpdateNode or none() }
+
+  query predicate postWithInFlow(Node n, string msg) {
+    isPostUpdateNode(n) and
+    not clearsContent(n, _) and
+    simpleLocalFlowStep(_, n) and
+    not any(ConsistencyConfiguration c).postWithInFlowExclude(n) and
+    msg = "PostUpdateNode should not be the target of local flow."
+  }
+
+  query predicate viableImplInCallContextTooLarge(
+    DataFlowCall call, DataFlowCall ctx, DataFlowCallable callable
+  ) {
+    callable = viableImplInCallContext(call, ctx) and
+    not callable = viableCallable(call) and
+    not any(ConsistencyConfiguration c).viableImplInCallContextTooLargeExclude(call, ctx, callable)
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowImplSpecific.qll

@@ -0,0 +1,11 @@
+/**
+ * Provides IR-specific definitions for use in the data flow library.
+ */
+module Private {
+  import DataFlowPrivate
+  import DataFlowDispatch
+}
+
+module Public {
+  import DataFlowUtil
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/DataFlowPrivate.qll

@@ -0,0 +1,560 @@
+private import cpp as Cpp
+private import DataFlowUtil
+private import semmle.code.cpp.ir.IR
+private import DataFlowDispatch
+private import DataFlowImplConsistency
+private import semmle.code.cpp.ir.internal.IRCppLanguage
+private import SsaInternals as Ssa
+
+/** Gets the callable in which this node occurs. */
+DataFlowCallable nodeGetEnclosingCallable(Node n) { result = n.getEnclosingCallable() }
+
+/** Holds if `p` is a `ParameterNode` of `c` with position `pos`. */
+predicate isParameterNode(ParameterNode p, DataFlowCallable c, ParameterPosition pos) {
+  p.isParameterOf(c, pos)
+}
+
+/** Holds if `arg` is an `ArgumentNode` of `c` with position `pos`. */
+predicate isArgumentNode(ArgumentNode arg, DataFlowCall c, ArgumentPosition pos) {
+  arg.argumentOf(c, pos)
+}
+
+/**
+ * A data flow node that occurs as the argument of a call and is passed as-is
+ * to the callable. Instance arguments (`this` pointer) and read side effects
+ * on parameters are also included.
+ */
+abstract class ArgumentNode extends Node {
+  /**
+   * Holds if this argument occurs at the given position in the given call.
+   * The instance argument is considered to have index `-1`.
+   */
+  abstract predicate argumentOf(DataFlowCall call, ArgumentPosition pos);
+
+  /** Gets the call in which this node is an argument. */
+  DataFlowCall getCall() { this.argumentOf(result, _) }
+}
+
+/**
+ * A data flow node that occurs as the argument to a call, or an
+ * implicit `this` pointer argument.
+ */
+private class PrimaryArgumentNode extends ArgumentNode, OperandNode {
+  override ArgumentOperand op;
+
+  PrimaryArgumentNode() { exists(CallInstruction call | op = call.getAnArgumentOperand()) }
+
+  override predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
+    op = call.getArgumentOperand(pos.(DirectPosition).getIndex())
+  }
+
+  override string toStringImpl() { result = argumentOperandToString(op) }
+}
+
+private string argumentOperandToString(ArgumentOperand op) {
+  exists(Expr unconverted |
+    unconverted = op.getDef().getUnconvertedResultExpression() and
+    result = unconverted.toString()
+  )
+  or
+  // Certain instructions don't map to an unconverted result expression. For these cases
+  // we fall back to a simpler naming scheme. This can happen in IR-generated constructors.
+  not exists(op.getDef().getUnconvertedResultExpression()) and
+  (
+    result = "Argument " + op.(PositionalArgumentOperand).getIndex()
+    or
+    op instanceof ThisArgumentOperand and result = "Argument this"
+  )
+}
+
+private class SideEffectArgumentNode extends ArgumentNode, SideEffectOperandNode {
+  override predicate argumentOf(DataFlowCall dfCall, ArgumentPosition pos) {
+    this.getCallInstruction() = dfCall and
+    pos.(IndirectionPosition).getArgumentIndex() = this.getArgumentIndex() and
+    pos.(IndirectionPosition).getIndirectionIndex() = super.getIndirectionIndex()
+  }
+
+  override string toStringImpl() {
+    result = argumentOperandToString(this.getAddressOperand()) + " indirection"
+  }
+}
+
+/** A parameter position represented by an integer. */
+class ParameterPosition = Position;
+
+/** An argument position represented by an integer. */
+class ArgumentPosition = Position;
+
+class Position extends TPosition {
+  abstract string toString();
+}
+
+class DirectPosition extends Position, TDirectPosition {
+  int index;
+
+  DirectPosition() { this = TDirectPosition(index) }
+
+  override string toString() { if index = -1 then result = "this" else result = index.toString() }
+
+  int getIndex() { result = index }
+}
+
+class IndirectionPosition extends Position, TIndirectionPosition {
+  int argumentIndex;
+  int indirectionIndex;
+
+  IndirectionPosition() { this = TIndirectionPosition(argumentIndex, indirectionIndex) }
+
+  override string toString() {
+    if argumentIndex = -1
+    then if indirectionIndex > 0 then result = "this indirection" else result = "this"
+    else
+      if indirectionIndex > 0
+      then result = argumentIndex.toString() + " indirection"
+      else result = argumentIndex.toString()
+  }
+
+  int getArgumentIndex() { result = argumentIndex }
+
+  int getIndirectionIndex() { result = indirectionIndex }
+}
+
+newtype TPosition =
+  TDirectPosition(int index) { exists(any(CallInstruction c).getArgument(index)) } or
+  TIndirectionPosition(int argumentIndex, int indirectionIndex) {
+    hasOperandAndIndex(_, any(CallInstruction call).getArgumentOperand(argumentIndex),
+      indirectionIndex)
+  }
+
+private newtype TReturnKind =
+  TNormalReturnKind(int index) {
+    exists(IndirectReturnNode return |
+      return.getAddressOperand() = any(ReturnValueInstruction r).getReturnAddressOperand() and
+      index = return.getIndirectionIndex() - 1 // We subtract one because the return loads the value.
+    )
+  } or
+  TIndirectReturnKind(int argumentIndex, int indirectionIndex) {
+    exists(IndirectReturnNode return, ReturnIndirectionInstruction returnInd |
+      returnInd.hasIndex(argumentIndex) and
+      return.getAddressOperand() = returnInd.getSourceAddressOperand() and
+      indirectionIndex = return.getIndirectionIndex()
+    )
+  }
+
+/**
+ * A return kind. A return kind describes how a value can be returned
+ * from a callable. For C++, this is simply a function return.
+ */
+class ReturnKind extends TReturnKind {
+  /** Gets a textual representation of this return kind. */
+  abstract string toString();
+}
+
+private class NormalReturnKind extends ReturnKind, TNormalReturnKind {
+  int index;
+
+  NormalReturnKind() { this = TNormalReturnKind(index) }
+
+  override string toString() { result = "indirect return" }
+}
+
+private class IndirectReturnKind extends ReturnKind, TIndirectReturnKind {
+  int argumentIndex;
+  int indirectionIndex;
+
+  IndirectReturnKind() { this = TIndirectReturnKind(argumentIndex, indirectionIndex) }
+
+  override string toString() { result = "indirect outparam[" + argumentIndex.toString() + "]" }
+}
+
+/** A data flow node that occurs as the result of a `ReturnStmt`. */
+class ReturnNode extends Node instanceof IndirectReturnNode {
+  /** Gets the kind of this returned value. */
+  abstract ReturnKind getKind();
+}
+
+/**
+ * This predicate represents an annoying hack that we have to do. We use the
+ * `ReturnIndirectionInstruction` to determine which variables need flow back
+ * out of a function. However, the IR will unconditionally create those for a
+ * variable passed to a function even though the variable was never updated by
+ * the function. And if a function has too many `ReturnNode`s the dataflow
+ * library lowers its precision for that function by disabling field flow.
+ *
+ * So we those eliminate `ReturnNode`s that would have otherwise been created
+ * by this unconditional `ReturnIndirectionInstruction` by requiring that there
+ * must exist an SSA definition of the IR variable in the function.
+ */
+private predicate hasNonInitializeParameterDef(IRVariable v) {
+  exists(Ssa::Def def |
+    not def.getDefiningInstruction() instanceof InitializeParameterInstruction and
+    v = def.getSourceVariable().getBaseVariable().(Ssa::BaseIRVariable).getIRVariable()
+  )
+}
+
+class ReturnIndirectionNode extends IndirectReturnNode, ReturnNode {
+  override ReturnKind getKind() {
+    exists(int argumentIndex, ReturnIndirectionInstruction returnInd |
+      returnInd.hasIndex(argumentIndex) and
+      this.getAddressOperand() = returnInd.getSourceAddressOperand() and
+      result = TIndirectReturnKind(argumentIndex, this.getIndirectionIndex()) and
+      hasNonInitializeParameterDef(returnInd.getIRVariable())
+    )
+    or
+    this.getAddressOperand() = any(ReturnValueInstruction r).getReturnAddressOperand() and
+    result = TNormalReturnKind(this.getIndirectionIndex() - 1)
+  }
+}
+
+private Operand fullyConvertedCallStep(Operand op) {
+  not exists(getANonConversionUse(op)) and
+  exists(Instruction instr |
+    conversionFlow(op, instr, _) and
+    result = getAUse(instr)
+  )
+}
+
+/**
+ * Gets the instruction that uses this operand, if the instruction is not
+ * ignored for dataflow purposes.
+ */
+private Instruction getUse(Operand op) {
+  result = op.getUse() and
+  not Ssa::ignoreOperand(op)
+}
+
+/** Gets a use of the instruction `instr` that is not ignored for dataflow purposes. */
+Operand getAUse(Instruction instr) {
+  result = instr.getAUse() and
+  not Ssa::ignoreOperand(result)
+}
+
+/**
+ * Gets a use of `operand` that is:
+ * - not ignored for dataflow purposes, and
+ * - not a conversion-like instruction.
+ */
+private Instruction getANonConversionUse(Operand operand) {
+  result = getUse(operand) and
+  not conversionFlow(_, result, _)
+}
+
+/**
+ * Gets the operand that represents the first use of the value of `call` following
+ * a sequnce of conversion-like instructions.
+ */
+predicate operandForfullyConvertedCall(Operand operand, CallInstruction call) {
+  exists(getANonConversionUse(operand)) and
+  (
+    operand = getAUse(call)
+    or
+    operand = fullyConvertedCallStep*(getAUse(call))
+  )
+}
+
+/**
+ * Gets the instruction that represents the first use of the value of `call` following
+ * a sequnce of conversion-like instructions.
+ *
+ * This predicate only holds if there is no suitable operand (i.e., no operand of a non-
+ * conversion instruction) to use to represent the value of `call` after conversions.
+ */
+predicate instructionForfullyConvertedCall(Instruction instr, CallInstruction call) {
+  not operandForfullyConvertedCall(_, call) and
+  (
+    // If there is no use of the call then we pick the call instruction
+    not exists(getAUse(call)) and
+    instr = call
+    or
+    // Otherwise, flow to the first non-conversion use.
+    exists(Operand operand | operand = fullyConvertedCallStep*(getAUse(call)) |
+      instr = getANonConversionUse(operand)
+    )
+  )
+}
+
+/** Holds if `node` represents the output node for `call`. */
+private predicate simpleOutNode(Node node, CallInstruction call) {
+  operandForfullyConvertedCall(node.asOperand(), call)
+  or
+  instructionForfullyConvertedCall(node.asInstruction(), call)
+}
+
+/** A data flow node that represents the output of a call. */
+class OutNode extends Node {
+  OutNode() {
+    // Return values not hidden behind indirections
+    simpleOutNode(this, _)
+    or
+    // Return values hidden behind indirections
+    this instanceof IndirectReturnOutNode
+    or
+    // Modified arguments hidden behind indirections
+    this instanceof IndirectArgumentOutNode
+  }
+
+  /** Gets the underlying call. */
+  abstract DataFlowCall getCall();
+
+  abstract ReturnKind getReturnKind();
+}
+
+private class DirectCallOutNode extends OutNode {
+  CallInstruction call;
+
+  DirectCallOutNode() { simpleOutNode(this, call) }
+
+  override DataFlowCall getCall() { result = call }
+
+  override ReturnKind getReturnKind() { result = TNormalReturnKind(0) }
+}
+
+private class IndirectCallOutNode extends OutNode, IndirectReturnOutNode {
+  override DataFlowCall getCall() { result = this.getCallInstruction() }
+
+  override ReturnKind getReturnKind() { result = TNormalReturnKind(this.getIndirectionIndex()) }
+}
+
+private class SideEffectOutNode extends OutNode, IndirectArgumentOutNode {
+  override DataFlowCall getCall() { result = this.getCallInstruction() }
+
+  override ReturnKind getReturnKind() {
+    result = TIndirectReturnKind(this.getArgumentIndex(), this.getIndirectionIndex())
+  }
+}
+
+/**
+ * Gets a node that can read the value returned from `call` with return kind
+ * `kind`.
+ */
+OutNode getAnOutNode(DataFlowCall call, ReturnKind kind) {
+  result.getCall() = call and
+  result.getReturnKind() = kind
+}
+
+/**
+ * Holds if data can flow from `node1` to `node2` in a way that loses the
+ * calling context. For example, this would happen with flow through a
+ * global or static variable.
+ */
+predicate jumpStep(Node n1, Node n2) {
+  exists(Cpp::GlobalOrNamespaceVariable v |
+    v =
+      n1.asInstruction()
+          .(StoreInstruction)
+          .getResultAddress()
+          .(VariableAddressInstruction)
+          .getAstVariable() and
+    v = n2.asVariable()
+    or
+    v =
+      n2.asInstruction()
+          .(LoadInstruction)
+          .getSourceAddress()
+          .(VariableAddressInstruction)
+          .getAstVariable() and
+    v = n1.asVariable()
+  )
+}
+
+/**
+ * Holds if data can flow from `node1` to `node2` via an assignment to `f`.
+ * Thus, `node2` references an object with a field `f` that contains the
+ * value of `node1`.
+ */
+predicate storeStep(Node node1, Content c, PostFieldUpdateNode node2) {
+  exists(int indirectionIndex1, int numberOfLoads, StoreInstruction store |
+    nodeHasInstruction(node1, store, pragma[only_bind_into](indirectionIndex1)) and
+    node2.getIndirectionIndex() = 1 and
+    numberOfLoadsFromOperand(node2.getFieldAddress(), store.getDestinationAddressOperand(),
+      numberOfLoads)
+  |
+    exists(FieldContent fc | fc = c |
+      fc.getField() = node2.getUpdatedField() and
+      fc.getIndirectionIndex() = 1 + indirectionIndex1 + numberOfLoads
+    )
+    or
+    exists(UnionContent uc | uc = c |
+      uc.getAField() = node2.getUpdatedField() and
+      uc.getIndirectionIndex() = 1 + indirectionIndex1 + numberOfLoads
+    )
+  )
+}
+
+/**
+ * Holds if `operandFrom` flows to `operandTo` using a sequence of conversion-like
+ * operations and exactly `n` `LoadInstruction` operations.
+ */
+private predicate numberOfLoadsFromOperandRec(Operand operandFrom, Operand operandTo, int ind) {
+  exists(LoadInstruction load | load.getSourceAddressOperand() = operandFrom |
+    operandTo = operandFrom and ind = 0
+    or
+    numberOfLoadsFromOperand(load.getAUse(), operandTo, ind - 1)
+  )
+  or
+  exists(Operand op, Instruction instr |
+    instr = op.getDef() and
+    conversionFlow(operandFrom, instr, _) and
+    numberOfLoadsFromOperand(op, operandTo, ind)
+  )
+}
+
+/**
+ * Holds if `operandFrom` flows to `operandTo` using a sequence of conversion-like
+ * operations and exactly `n` `LoadInstruction` operations.
+ */
+private predicate numberOfLoadsFromOperand(Operand operandFrom, Operand operandTo, int n) {
+  numberOfLoadsFromOperandRec(operandFrom, operandTo, n)
+  or
+  not any(LoadInstruction load).getSourceAddressOperand() = operandFrom and
+  not conversionFlow(operandFrom, _, _) and
+  operandFrom = operandTo and
+  n = 0
+}
+
+// Needed to join on both an operand and an index at the same time.
+pragma[noinline]
+predicate nodeHasOperand(Node node, Operand operand, int indirectionIndex) {
+  node.asOperand() = operand and indirectionIndex = 0
+  or
+  hasOperandAndIndex(node, operand, indirectionIndex)
+}
+
+// Needed to join on both an instruction and an index at the same time.
+pragma[noinline]
+predicate nodeHasInstruction(Node node, Instruction instr, int indirectionIndex) {
+  node.asInstruction() = instr and indirectionIndex = 0
+  or
+  hasInstructionAndIndex(node, instr, indirectionIndex)
+}
+
+/**
+ * Holds if data can flow from `node1` to `node2` via a read of `f`.
+ * Thus, `node1` references an object with a field `f` whose value ends up in
+ * `node2`.
+ */
+predicate readStep(Node node1, Content c, Node node2) {
+  exists(FieldAddress fa1, Operand operand, int numberOfLoads, int indirectionIndex2 |
+    nodeHasOperand(node2, operand, indirectionIndex2) and
+    nodeHasOperand(node1, fa1.getObjectAddressOperand(), _) and
+    numberOfLoadsFromOperand(fa1, operand, numberOfLoads)
+  |
+    exists(FieldContent fc | fc = c |
+      fc.getField() = fa1.getField() and
+      fc.getIndirectionIndex() = indirectionIndex2 + numberOfLoads
+    )
+    or
+    exists(UnionContent uc | uc = c |
+      uc.getAField() = fa1.getField() and
+      uc.getIndirectionIndex() = indirectionIndex2 + numberOfLoads
+    )
+  )
+}
+
+/**
+ * Holds if values stored inside content `c` are cleared at node `n`.
+ */
+predicate clearsContent(Node n, Content c) {
+  none() // stub implementation
+}
+
+/**
+ * Holds if the value that is being tracked is expected to be stored inside content `c`
+ * at node `n`.
+ */
+predicate expectsContent(Node n, ContentSet c) { none() }
+
+/** Gets the type of `n` used for type pruning. */
+DataFlowType getNodeType(Node n) {
+  suppressUnusedNode(n) and
+  result instanceof VoidType // stub implementation
+}
+
+/** Gets a string representation of a type returned by `getNodeType`. */
+string ppReprType(DataFlowType t) { none() } // stub implementation
+
+/**
+ * Holds if `t1` and `t2` are compatible, that is, whether data can flow from
+ * a node of type `t1` to a node of type `t2`.
+ */
+pragma[inline]
+predicate compatibleTypes(DataFlowType t1, DataFlowType t2) {
+  any() // stub implementation
+}
+
+private predicate suppressUnusedNode(Node n) { any() }
+
+//////////////////////////////////////////////////////////////////////////////
+// Java QL library compatibility wrappers
+//////////////////////////////////////////////////////////////////////////////
+/** A node that performs a type cast. */
+class CastNode extends Node {
+  CastNode() { none() } // stub implementation
+}
+
+/**
+ * A function that may contain code or a variable that may contain itself. When
+ * flow crosses from one _enclosing callable_ to another, the interprocedural
+ * data-flow library discards call contexts and inserts a node in the big-step
+ * relation used for human-readable path explanations.
+ */
+class DataFlowCallable = Cpp::Declaration;
+
+class DataFlowExpr = Expr;
+
+class DataFlowType = Type;
+
+/** A function call relevant for data flow. */
+class DataFlowCall extends CallInstruction {
+  Function getEnclosingCallable() { result = this.getEnclosingFunction() }
+}
+
+predicate isUnreachableInCall(Node n, DataFlowCall call) { none() } // stub implementation
+
+int accessPathLimit() { result = 5 }
+
+/**
+ * Holds if access paths with `c` at their head always should be tracked at high
+ * precision. This disables adaptive access path precision for such access paths.
+ */
+predicate forceHighPrecision(Content c) { none() }
+
+/** The unit type. */
+private newtype TUnit = TMkUnit()
+
+/** The trivial type with a single element. */
+class Unit extends TUnit {
+  /** Gets a textual representation of this element. */
+  string toString() { result = "unit" }
+}
+
+/** Holds if `n` should be hidden from path explanations. */
+predicate nodeIsHidden(Node n) { n instanceof OperandNode and not n instanceof ArgumentNode }
+
+class LambdaCallKind = Unit;
+
+/** Holds if `creation` is an expression that creates a lambda of kind `kind` for `c`. */
+predicate lambdaCreation(Node creation, LambdaCallKind kind, DataFlowCallable c) { none() }
+
+/** Holds if `call` is a lambda call of kind `kind` where `receiver` is the lambda expression. */
+predicate lambdaCall(DataFlowCall call, LambdaCallKind kind, Node receiver) { none() }
+
+/** Extra data-flow steps needed for lambda flow analysis. */
+predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preservesValue) { none() }
+
+/**
+ * Holds if flow is allowed to pass from parameter `p` and back to itself as a
+ * side-effect, resulting in a summary from `p` to itself.
+ *
+ * One example would be to allow flow like `p.foo = p.bar;`, which is disallowed
+ * by default as a heuristic.
+ */
+predicate allowParameterReturnInSelf(ParameterNode p) { none() }
+
+private class MyConsistencyConfiguration extends Consistency::ConsistencyConfiguration {
+  override predicate argHasPostUpdateExclude(ArgumentNode n) {
+    // The rules for whether an IR argument gets a post-update node are too
+    // complex to model here.
+    any()
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/ModelUtil.qll

@@ -0,0 +1,93 @@
+/**
+ * Provides predicates for mapping the `FunctionInput` and `FunctionOutput`
+ * classes used in function models to the corresponding instructions.
+ */
+
+private import semmle.code.cpp.ir.IR
+private import experimental.semmle.code.cpp.ir.dataflow.DataFlow
+private import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
+private import SsaInternals as Ssa
+
+/**
+ * Gets the instruction that goes into `input` for `call`.
+ */
+DataFlow::Node callInput(CallInstruction call, FunctionInput input) {
+  // An argument or qualifier
+  exists(int index |
+    result.asOperand() = call.getArgumentOperand(index) and
+    input.isParameterOrQualifierAddress(index)
+  )
+  or
+  // A value pointed to by an argument or qualifier
+  exists(int index, int indirectionIndex |
+    hasOperandAndIndex(result, call.getArgumentOperand(index), indirectionIndex) and
+    input.isParameterDerefOrQualifierObject(index, indirectionIndex)
+  )
+  or
+  exists(int ind |
+    result = getIndirectReturnOutNode(call, ind) and
+    input.isReturnValueDeref(ind)
+  )
+}
+
+/**
+ * Gets the instruction that holds the `output` for `call`.
+ */
+Node callOutput(CallInstruction call, FunctionOutput output) {
+  // The return value
+  result.asInstruction() = call and
+  output.isReturnValue()
+  or
+  // The side effect of a call on the value pointed to by an argument or qualifier
+  exists(int index, int indirectionIndex |
+    result.(IndirectArgumentOutNode).getArgumentIndex() = index and
+    result.(IndirectArgumentOutNode).getIndirectionIndex() = indirectionIndex and
+    result.(IndirectArgumentOutNode).getCallInstruction() = call and
+    output.isParameterDerefOrQualifierObject(index, indirectionIndex)
+  )
+  or
+  exists(int ind |
+    result = getIndirectReturnOutNode(call, ind) and
+    output.isReturnValueDeref(ind)
+  )
+}
+
+DataFlow::Node callInput(CallInstruction call, FunctionInput input, int d) {
+  exists(DataFlow::Node n | n = callInput(call, input) and d > 0 |
+    // An argument or qualifier
+    hasOperandAndIndex(result, n.asOperand(), d)
+    or
+    exists(Operand operand, int indirectionIndex |
+      // A value pointed to by an argument or qualifier
+      hasOperandAndIndex(n, operand, indirectionIndex) and
+      hasOperandAndIndex(result, operand, indirectionIndex + d)
+    )
+  )
+}
+
+private IndirectReturnOutNode getIndirectReturnOutNode(CallInstruction call, int d) {
+  result.getCallInstruction() = call and
+  result.getIndirectionIndex() = d
+}
+
+/**
+ * Gets the instruction that holds the `output` for `call`.
+ */
+bindingset[d]
+Node callOutput(CallInstruction call, FunctionOutput output, int d) {
+  exists(DataFlow::Node n | n = callOutput(call, output) and d > 0 |
+    // The return value
+    result = getIndirectReturnOutNode(n.asInstruction(), d)
+    or
+    // If there isn't an indirect out node for the call with indirection `d` then
+    // we conflate this with the underlying `CallInstruction`.
+    not exists(getIndirectReturnOutNode(call, d)) and
+    n.asInstruction() = result.asInstruction()
+    or
+    // The side effect of a call on the value pointed to by an argument or qualifier
+    exists(Operand operand, int indirectionIndex |
+      Ssa::outNodeHasAddressAndIndex(n, operand, indirectionIndex) and
+      Ssa::outNodeHasAddressAndIndex(result, operand, indirectionIndex + d)
+    )
+  )
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/PrintIRLocalFlow.qll

@@ -0,0 +1,136 @@
+private import cpp
+// The `ValueNumbering` library has to be imported right after `cpp` to ensure
+// that the cached IR gets the same checksum here as it does in queries that use
+// `ValueNumbering` without `DataFlow`.
+private import semmle.code.cpp.ir.ValueNumbering
+private import semmle.code.cpp.ir.IR
+private import semmle.code.cpp.ir.dataflow.DataFlow
+private import semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
+private import PrintIRUtilities
+
+/**
+ * Gets the local dataflow from other nodes in the same function to this node.
+ */
+private string getFromFlow(DataFlow::Node useNode, int order1, int order2) {
+  exists(DataFlow::Node defNode, string prefix |
+    (
+      simpleLocalFlowStep(defNode, useNode) and prefix = ""
+      or
+      any(DataFlow::Configuration cfg).isAdditionalFlowStep(defNode, useNode) and
+      defNode.getEnclosingCallable() = useNode.getEnclosingCallable() and
+      prefix = "+"
+    ) and
+    if defNode.asInstruction() = useNode.asOperand().getAnyDef()
+    then
+      // Shorthand for flow from the def of this operand.
+      result = prefix + "def" and
+      order1 = -1 and
+      order2 = 0
+    else
+      if defNode.asOperand().getUse() = useNode.asInstruction()
+      then
+        // Shorthand for flow from an operand of this instruction
+        result = prefix + defNode.asOperand().getDumpId() and
+        order1 = -1 and
+        order2 = defNode.asOperand().getDumpSortOrder()
+      else result = prefix + nodeId(defNode, order1, order2)
+  )
+}
+
+/**
+ * Gets the local dataflow from this node to other nodes in the same function.
+ */
+private string getToFlow(DataFlow::Node defNode, int order1, int order2) {
+  exists(DataFlow::Node useNode, string prefix |
+    (
+      simpleLocalFlowStep(defNode, useNode) and prefix = ""
+      or
+      any(DataFlow::Configuration cfg).isAdditionalFlowStep(defNode, useNode) and
+      defNode.getEnclosingCallable() = useNode.getEnclosingCallable() and
+      prefix = "+"
+    ) and
+    if useNode.asInstruction() = defNode.asOperand().getUse()
+    then
+      // Shorthand for flow to this operand's instruction.
+      result = prefix + "result" and
+      order1 = -1 and
+      order2 = 0
+    else result = prefix + nodeId(useNode, order1, order2)
+  )
+}
+
+/**
+ * Gets the properties of the dataflow node `node`.
+ */
+private string getNodeProperty(DataFlow::Node node, string key) {
+  // List dataflow into and out of this node. Flow into this node is printed as `src->@`, and flow
+  // out of this node is printed as `@->dest`.
+  key = "flow" and
+  result =
+    strictconcat(string flow, boolean to, int order1, int order2 |
+      flow = getFromFlow(node, order1, order2) + "->@" and to = false
+      or
+      flow = "@->" + getToFlow(node, order1, order2) and to = true
+    |
+      flow, ", " order by to, order1, order2, flow
+    )
+  or
+  // Is this node a dataflow sink?
+  key = "sink" and
+  any(DataFlow::Configuration cfg).isSink(node) and
+  result = "true"
+  or
+  // Is this node a dataflow source?
+  key = "source" and
+  any(DataFlow::Configuration cfg).isSource(node) and
+  result = "true"
+  or
+  // Is this node a dataflow barrier, and if so, what kind?
+  key = "barrier" and
+  result =
+    strictconcat(string kind |
+      any(DataFlow::Configuration cfg).isBarrier(node) and kind = "full"
+      or
+      any(DataFlow::Configuration cfg).isBarrierIn(node) and kind = "in"
+      or
+      any(DataFlow::Configuration cfg).isBarrierOut(node) and kind = "out"
+    |
+      kind, ", "
+    )
+  or
+  // Is there partial flow from a source to this node?
+  // This property will only be emitted if partial flow is enabled by overriding
+  // `DataFlow::Configration::explorationLimit()`.
+  key = "pflow" and
+  result =
+    strictconcat(DataFlow::PartialPathNode sourceNode, DataFlow::PartialPathNode destNode, int dist,
+      int order1, int order2 |
+      any(DataFlow::Configuration cfg).hasPartialFlow(sourceNode, destNode, dist) and
+      destNode.getNode() = node and
+      // Only print flow from a source in the same function.
+      sourceNode.getNode().getEnclosingCallable() = node.getEnclosingCallable()
+    |
+      nodeId(sourceNode.getNode(), order1, order2) + "+" + dist.toString(), ", "
+      order by
+        order1, order2, dist desc
+    )
+}
+
+/**
+ * Property provider for local IR dataflow.
+ */
+class LocalFlowPropertyProvider extends IRPropertyProvider {
+  override string getOperandProperty(Operand operand, string key) {
+    exists(DataFlow::Node node |
+      operand = node.asOperand() and
+      result = getNodeProperty(node, key)
+    )
+  }
+
+  override string getInstructionProperty(Instruction instruction, string key) {
+    exists(DataFlow::Node node |
+      instruction = node.asInstruction() and
+      result = getNodeProperty(node, key)
+    )
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/PrintIRStoreSteps.qll

@@ -0,0 +1,33 @@
+/**
+ * Print the dataflow local store steps in IR dumps.
+ */
+
+private import cpp
+// The `ValueNumbering` library has to be imported right after `cpp` to ensure
+// that the cached IR gets the same checksum here as it does in queries that use
+// `ValueNumbering` without `DataFlow`.
+private import semmle.code.cpp.ir.ValueNumbering
+private import semmle.code.cpp.ir.IR
+private import semmle.code.cpp.ir.dataflow.DataFlow
+private import semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
+private import semmle.code.cpp.ir.dataflow.internal.DataFlowPrivate
+private import PrintIRUtilities
+
+/**
+ * Property provider for local IR dataflow store steps.
+ */
+class LocalFlowPropertyProvider extends IRPropertyProvider {
+  override string getInstructionProperty(Instruction instruction, string key) {
+    exists(DataFlow::Node objectNode, Content content |
+      key = "content[" + content.toString() + "]" and
+      instruction = objectNode.asInstruction() and
+      result =
+        strictconcat(string element, DataFlow::Node fieldNode |
+          storeStep(fieldNode, content, objectNode) and
+          element = nodeId(fieldNode, _, _)
+        |
+          element, ", "
+        )
+    )
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/PrintIRUtilities.qll

@@ -0,0 +1,39 @@
+/**
+ * Shared utilities used when printing dataflow annotations in IR dumps.
+ */
+
+private import cpp
+// The `ValueNumbering` library has to be imported right after `cpp` to ensure
+// that the cached IR gets the same checksum here as it does in queries that use
+// `ValueNumbering` without `DataFlow`.
+private import semmle.code.cpp.ir.ValueNumbering
+private import semmle.code.cpp.ir.IR
+private import semmle.code.cpp.ir.dataflow.DataFlow
+
+/**
+ * Gets a short ID for an IR dataflow node.
+ * - For `Instruction`s, this is just the result ID of the instruction (e.g. `m128`).
+ * - For `Operand`s, this is the label of the operand, prefixed with the result ID of the
+ *   instruction and a dot (e.g. `m128.left`).
+ * - For `Variable`s, this is the qualified name of the variable.
+ */
+string nodeId(DataFlow::Node node, int order1, int order2) {
+  exists(Instruction instruction | instruction = node.asInstruction() |
+    result = instruction.getResultId() and
+    order1 = instruction.getBlock().getDisplayIndex() and
+    order2 = instruction.getDisplayIndexInBlock()
+  )
+  or
+  exists(Operand operand, Instruction instruction |
+    operand = node.asOperand() and
+    instruction = operand.getUse()
+  |
+    result = instruction.getResultId() + "." + operand.getDumpId() and
+    order1 = instruction.getBlock().getDisplayIndex() and
+    order2 = instruction.getDisplayIndexInBlock()
+  )
+  or
+  result = "var(" + node.asVariable().getQualifiedName() + ")" and
+  order1 = 1000000 and
+  order2 = 0
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll

@@ -0,0 +1,552 @@
+private import codeql.ssa.Ssa as SsaImplCommon
+private import semmle.code.cpp.ir.IR
+private import DataFlowUtil
+private import DataFlowImplCommon as DataFlowImplCommon
+private import semmle.code.cpp.models.interfaces.Allocation as Alloc
+private import semmle.code.cpp.models.interfaces.DataFlow as DataFlow
+private import semmle.code.cpp.ir.internal.IRCppLanguage
+private import DataFlowPrivate
+private import ssa0.SsaInternals as SsaInternals0
+import SsaInternalsCommon
+
+private module SourceVariables {
+  int getMaxIndirectionForIRVariable(IRVariable var) {
+    exists(Type type, boolean isGLValue |
+      var.getLanguageType().hasType(type, isGLValue) and
+      if isGLValue = true
+      then result = 1 + getMaxIndirectionsForType(type)
+      else result = getMaxIndirectionsForType(type)
+    )
+  }
+
+  class BaseSourceVariable = SsaInternals0::BaseSourceVariable;
+
+  class BaseIRVariable = SsaInternals0::BaseIRVariable;
+
+  class BaseCallVariable = SsaInternals0::BaseCallVariable;
+
+  cached
+  private newtype TSourceVariable =
+    TSourceIRVariable(BaseIRVariable baseVar, int ind) {
+      ind = [0 .. getMaxIndirectionForIRVariable(baseVar.getIRVariable())]
+    } or
+    TCallVariable(AllocationInstruction call, int ind) {
+      ind = [0 .. countIndirectionsForCppType(getResultLanguageType(call))]
+    }
+
+  abstract class SourceVariable extends TSourceVariable {
+    int ind;
+
+    bindingset[ind]
+    SourceVariable() { any() }
+
+    abstract string toString();
+
+    int getIndirection() { result = ind }
+
+    abstract BaseSourceVariable getBaseVariable();
+  }
+
+  class SourceIRVariable extends SourceVariable, TSourceIRVariable {
+    BaseIRVariable var;
+
+    SourceIRVariable() { this = TSourceIRVariable(var, ind) }
+
+    IRVariable getIRVariable() { result = var.getIRVariable() }
+
+    override BaseIRVariable getBaseVariable() { result.getIRVariable() = this.getIRVariable() }
+
+    override string toString() {
+      ind = 0 and
+      result = this.getIRVariable().toString()
+      or
+      ind > 0 and
+      result = this.getIRVariable().toString() + " indirection"
+    }
+  }
+
+  class CallVariable extends SourceVariable, TCallVariable {
+    AllocationInstruction call;
+
+    CallVariable() { this = TCallVariable(call, ind) }
+
+    AllocationInstruction getCall() { result = call }
+
+    override BaseCallVariable getBaseVariable() { result.getCallInstruction() = call }
+
+    override string toString() {
+      ind = 0 and
+      result = "Call"
+      or
+      ind > 0 and
+      result = "Call indirection"
+    }
+  }
+}
+
+import SourceVariables
+
+predicate hasIndirectOperand(Operand op, int indirectionIndex) {
+  exists(CppType type, int m |
+    not ignoreOperand(op) and
+    type = getLanguageType(op) and
+    m = countIndirectionsForCppType(type) and
+    indirectionIndex = [1 .. m]
+  )
+}
+
+predicate hasIndirectInstruction(Instruction instr, int indirectionIndex) {
+  exists(CppType type, int m |
+    not ignoreInstruction(instr) and
+    type = getResultLanguageType(instr) and
+    m = countIndirectionsForCppType(type) and
+    indirectionIndex = [1 .. m]
+  )
+}
+
+cached
+private newtype TDefOrUseImpl =
+  TDefImpl(Operand address, int indirectionIndex) {
+    isDef(_, _, address, _, _, indirectionIndex) and
+    // We only include the definition if the SSA pruning stage
+    // concluded that the definition is live after the write.
+    any(SsaInternals0::Def def).getAddressOperand() = address
+  } or
+  TUseImpl(Operand operand, int indirectionIndex) {
+    isUse(_, operand, _, _, indirectionIndex) and
+    not isDef(_, _, operand, _, _, _)
+  }
+
+abstract private class DefOrUseImpl extends TDefOrUseImpl {
+  /** Gets a textual representation of this element. */
+  abstract string toString();
+
+  /** Gets the block of this definition or use. */
+  abstract IRBlock getBlock();
+
+  /** Holds if this definition or use has index `index` in block `block`. */
+  abstract predicate hasIndexInBlock(IRBlock block, int index);
+
+  final predicate hasIndexInBlock(IRBlock block, int index, SourceVariable sv) {
+    this.hasIndexInBlock(block, index) and
+    sv = this.getSourceVariable()
+  }
+
+  /** Gets the location of this element. */
+  abstract Cpp::Location getLocation();
+
+  /**
+   * Gets the index (i.e., the number of loads required) of this
+   * definition or use.
+   *
+   * Note that this is _not_ the definition's (or use's) index in
+   * the enclosing basic block. To obtain this index, use
+   * `DefOrUseImpl::hasIndexInBlock/2` or `DefOrUseImpl::hasIndexInBlock/3`.
+   */
+  abstract int getIndirectionIndex();
+
+  /**
+   * Gets the instruction that computes the base of this definition or use.
+   * This is always a `VariableAddressInstruction` or an `AllocationInstruction`.
+   */
+  abstract Instruction getBase();
+
+  final BaseSourceVariable getBaseSourceVariable() {
+    exists(IRVariable var |
+      result.(BaseIRVariable).getIRVariable() = var and
+      instructionHasIRVariable(this.getBase(), var)
+    )
+    or
+    result.(BaseCallVariable).getCallInstruction() = this.getBase()
+  }
+
+  /** Gets the variable that is defined or used. */
+  final SourceVariable getSourceVariable() {
+    exists(BaseSourceVariable v, int ind |
+      sourceVariableHasBaseAndIndex(result, v, ind) and
+      defOrUseHasSourceVariable(this, v, ind)
+    )
+  }
+}
+
+pragma[noinline]
+private predicate instructionHasIRVariable(VariableAddressInstruction vai, IRVariable var) {
+  vai.getIRVariable() = var
+}
+
+private predicate defOrUseHasSourceVariable(DefOrUseImpl defOrUse, BaseSourceVariable bv, int ind) {
+  defHasSourceVariable(defOrUse, bv, ind)
+  or
+  useHasSourceVariable(defOrUse, bv, ind)
+}
+
+pragma[noinline]
+private predicate defHasSourceVariable(DefImpl def, BaseSourceVariable bv, int ind) {
+  bv = def.getBaseSourceVariable() and
+  ind = def.getIndirection()
+}
+
+pragma[noinline]
+private predicate useHasSourceVariable(UseImpl use, BaseSourceVariable bv, int ind) {
+  bv = use.getBaseSourceVariable() and
+  ind = use.getIndirection()
+}
+
+pragma[noinline]
+private predicate sourceVariableHasBaseAndIndex(SourceVariable v, BaseSourceVariable bv, int ind) {
+  v.getBaseVariable() = bv and
+  v.getIndirection() = ind
+}
+
+class DefImpl extends DefOrUseImpl, TDefImpl {
+  Operand address;
+  int ind;
+
+  DefImpl() { this = TDefImpl(address, ind) }
+
+  override Instruction getBase() { isDef(_, _, address, result, _, _) }
+
+  Operand getAddressOperand() { result = address }
+
+  int getIndirection() { isDef(_, _, address, _, result, ind) }
+
+  override int getIndirectionIndex() { result = ind }
+
+  Instruction getDefiningInstruction() { isDef(_, result, address, _, _, _) }
+
+  override string toString() { result = "DefImpl" }
+
+  override IRBlock getBlock() { result = this.getDefiningInstruction().getBlock() }
+
+  override Cpp::Location getLocation() { result = this.getDefiningInstruction().getLocation() }
+
+  final override predicate hasIndexInBlock(IRBlock block, int index) {
+    this.getDefiningInstruction() = block.getInstruction(index)
+  }
+
+  predicate isCertain() { isDef(true, _, address, _, _, ind) }
+}
+
+class UseImpl extends DefOrUseImpl, TUseImpl {
+  Operand operand;
+  int ind;
+
+  UseImpl() { this = TUseImpl(operand, ind) }
+
+  Operand getOperand() { result = operand }
+
+  override string toString() { result = "UseImpl" }
+
+  final override predicate hasIndexInBlock(IRBlock block, int index) {
+    operand.getUse() = block.getInstruction(index)
+  }
+
+  final override IRBlock getBlock() { result = operand.getUse().getBlock() }
+
+  final override Cpp::Location getLocation() { result = operand.getLocation() }
+
+  final int getIndirection() { isUse(_, operand, _, result, ind) }
+
+  override int getIndirectionIndex() { result = ind }
+
+  override Instruction getBase() { isUse(_, operand, result, _, ind) }
+
+  predicate isCertain() { isUse(true, operand, _, _, ind) }
+}
+
+/**
+ * Holds if `defOrUse1` is a definition which is first read by `use`,
+ * or if `defOrUse1` is a use and `use` is a next subsequent use.
+ *
+ * In both cases, `use` can either be an explicit use written in the
+ * source file, or it can be a phi node as computed by the SSA library.
+ */
+predicate adjacentDefRead(DefOrUse defOrUse1, UseOrPhi use) {
+  exists(IRBlock bb1, int i1, SourceVariable v |
+    defOrUse1.asDefOrUse().hasIndexInBlock(bb1, i1, v)
+  |
+    exists(IRBlock bb2, int i2 |
+      adjacentDefRead(_, pragma[only_bind_into](bb1), pragma[only_bind_into](i1),
+        pragma[only_bind_into](bb2), pragma[only_bind_into](i2))
+    |
+      use.asDefOrUse().(UseImpl).hasIndexInBlock(bb2, i2, v)
+    )
+    or
+    exists(PhiNode phi |
+      lastRefRedef(_, bb1, i1, phi) and
+      use.asPhi() = phi and
+      phi.getSourceVariable() = pragma[only_bind_into](v)
+    )
+  )
+}
+
+private predicate useToNode(UseOrPhi use, Node nodeTo) {
+  exists(UseImpl useImpl |
+    useImpl = use.asDefOrUse() and
+    nodeHasOperand(nodeTo, useImpl.getOperand(), useImpl.getIndirectionIndex())
+  )
+  or
+  nodeTo.(SsaPhiNode).getPhiNode() = use.asPhi()
+}
+
+pragma[noinline]
+predicate outNodeHasAddressAndIndex(
+  IndirectArgumentOutNode out, Operand address, int indirectionIndex
+) {
+  out.getAddressOperand() = address and
+  out.getIndirectionIndex() = indirectionIndex
+}
+
+private predicate defToNode(Node nodeFrom, Def def) {
+  nodeHasInstruction(nodeFrom, def.getDefiningInstruction(), def.getIndirectionIndex())
+}
+
+/**
+ * INTERNAL: Do not use.
+ *
+ * Holds if `nodeFrom` is the node that correspond to the definition or use `defOrUse`.
+ */
+predicate nodeToDefOrUse(Node nodeFrom, SsaDefOrUse defOrUse) {
+  // Node -> Def
+  defToNode(nodeFrom, defOrUse)
+  or
+  // Node -> Use
+  useToNode(defOrUse, nodeFrom)
+}
+
+/**
+ * Perform a single conversion-like step from `nFrom` to `nTo`. This relation
+ * only holds when there is no use-use relation out of `nTo`.
+ */
+private predicate indirectConversionFlowStep(Node nFrom, Node nTo) {
+  not exists(UseOrPhi defOrUse |
+    nodeToDefOrUse(nTo, defOrUse) and
+    adjacentDefRead(defOrUse, _)
+  ) and
+  exists(Operand op1, Operand op2, int indirectionIndex, Instruction instr |
+    hasOperandAndIndex(nFrom, op1, pragma[only_bind_into](indirectionIndex)) and
+    hasOperandAndIndex(nTo, op2, pragma[only_bind_into](indirectionIndex)) and
+    instr = op2.getDef() and
+    conversionFlow(op1, instr, _)
+  )
+}
+
+/**
+ * The reason for this predicate is a bit annoying:
+ * We cannot mark a `PointerArithmeticInstruction` that computes an offset based on some SSA
+ * variable `x` as a use of `x` since this creates taint-flow in the following example:
+ * ```c
+ * int x = array[source]
+ * sink(*array)
+ * ```
+ * This is because `source` would flow from the operand of `PointerArithmeticInstruction` to the
+ * result of the instruction, and into the `IndirectOperand` that represents the value of `*array`.
+ * Then, via use-use flow, flow will arrive at `*array` in `sink(*array)`.
+ *
+ * So this predicate recurses back along conversions and `PointerArithmeticInstruction`s to find the
+ * first use that has provides use-use flow, and uses that target as the target of the `nodeFrom`.
+ */
+private predicate adjustForPointerArith(Node nodeFrom, UseOrPhi use) {
+  nodeFrom = any(PostUpdateNode pun).getPreUpdateNode() and
+  exists(DefOrUse defOrUse, Node adjusted |
+    indirectConversionFlowStep*(adjusted, nodeFrom) and
+    nodeToDefOrUse(adjusted, defOrUse) and
+    adjacentDefRead(defOrUse, use)
+  )
+}
+
+/** Holds if there is def-use or use-use flow from `nodeFrom` to `nodeTo`. */
+predicate ssaFlow(Node nodeFrom, Node nodeTo) {
+  // `nodeFrom = any(PostUpdateNode pun).getPreUpdateNode()` is implied by adjustedForPointerArith.
+  exists(UseOrPhi use |
+    adjustForPointerArith(nodeFrom, use) and
+    useToNode(use, nodeTo)
+  )
+  or
+  not nodeFrom = any(PostUpdateNode pun).getPreUpdateNode() and
+  exists(DefOrUse defOrUse1, UseOrPhi use |
+    nodeToDefOrUse(nodeFrom, defOrUse1) and
+    adjacentDefRead(defOrUse1, use) and
+    useToNode(use, nodeTo)
+  )
+}
+
+/** Holds if `nodeTo` receives flow from the phi node `nodeFrom`. */
+predicate fromPhiNode(SsaPhiNode nodeFrom, Node nodeTo) {
+  exists(PhiNode phi, SourceVariable sv, IRBlock bb1, int i1, UseOrPhi use |
+    phi = nodeFrom.getPhiNode() and
+    phi.definesAt(sv, bb1, i1) and
+    useToNode(use, nodeTo)
+  |
+    exists(IRBlock bb2, int i2 |
+      use.asDefOrUse().hasIndexInBlock(bb2, i2, sv) and
+      adjacentDefRead(phi, bb1, i1, bb2, i2)
+    )
+    or
+    exists(PhiNode phiTo |
+      lastRefRedef(phi, _, _, phiTo) and
+      nodeTo.(SsaPhiNode).getPhiNode() = phiTo
+    )
+  )
+}
+
+private SsaInternals0::SourceVariable getOldSourceVariable(SourceVariable v) {
+  v.getBaseVariable().(BaseIRVariable).getIRVariable() =
+    result.getBaseVariable().(SsaInternals0::BaseIRVariable).getIRVariable()
+  or
+  v.getBaseVariable().(BaseCallVariable).getCallInstruction() =
+    result.getBaseVariable().(SsaInternals0::BaseCallVariable).getCallInstruction()
+}
+
+/**
+ * Holds if there is a write at index `i` in basic block `bb` to variable `v` that's
+ * subsequently read (as determined by the SSA pruning stage).
+ */
+private predicate variableWriteCand(IRBlock bb, int i, SourceVariable v) {
+  exists(SsaInternals0::Def def, SsaInternals0::SourceVariable v0 |
+    def.asDefOrUse().hasIndexInBlock(bb, i, v0) and
+    v0 = getOldSourceVariable(v)
+  )
+}
+
+private module SsaInput implements SsaImplCommon::InputSig {
+  import InputSigCommon
+  import SourceVariables
+
+  /**
+   * Holds if the `i`'th write in block `bb` writes to the variable `v`.
+   * `certain` is `true` if the write is guaranteed to overwrite the entire variable.
+   */
+  predicate variableWrite(IRBlock bb, int i, SourceVariable v, boolean certain) {
+    DataFlowImplCommon::forceCachingInSameStage() and
+    variableWriteCand(bb, i, v) and
+    exists(DefImpl def | def.hasIndexInBlock(bb, i, v) |
+      if def.isCertain() then certain = true else certain = false
+    )
+  }
+
+  /**
+   * Holds if the `i`'th read in block `bb` reads to the variable `v`.
+   * `certain` is `true` if the read is guaranteed. For C++, this is always the case.
+   */
+  predicate variableRead(IRBlock bb, int i, SourceVariable v, boolean certain) {
+    exists(UseImpl use | use.hasIndexInBlock(bb, i, v) |
+      if use.isCertain() then certain = true else certain = false
+    )
+  }
+}
+
+/**
+ * The final SSA predicates used for dataflow purposes.
+ */
+cached
+module SsaCached {
+  /**
+   * Holds if `def` is accessed at index `i1` in basic block `bb1` (either a read
+   * or a write), `def` is read at index `i2` in basic block `bb2`, and there is a
+   * path between them without any read of `def`.
+   */
+  cached
+  predicate adjacentDefRead(Definition def, IRBlock bb1, int i1, IRBlock bb2, int i2) {
+    SsaImpl::adjacentDefRead(def, bb1, i1, bb2, i2)
+  }
+
+  /**
+   * Holds if the node at index `i` in `bb` is a last reference to SSA definition
+   * `def`. The reference is last because it can reach another write `next`,
+   * without passing through another read or write.
+   */
+  cached
+  predicate lastRefRedef(Definition def, IRBlock bb, int i, Definition next) {
+    SsaImpl::lastRefRedef(def, bb, i, next)
+  }
+}
+
+cached
+private newtype TSsaDefOrUse =
+  TDefOrUse(DefOrUseImpl defOrUse) {
+    defOrUse instanceof UseImpl
+    or
+    // Like in the pruning stage, we only include definition that's live after the
+    // write as the final definitions computed by SSA.
+    exists(Definition def, SourceVariable sv, IRBlock bb, int i |
+      def.definesAt(sv, bb, i) and
+      defOrUse.(DefImpl).hasIndexInBlock(bb, i, sv)
+    )
+  } or
+  TPhi(PhiNode phi)
+
+abstract private class SsaDefOrUse extends TSsaDefOrUse {
+  string toString() { none() }
+
+  DefOrUseImpl asDefOrUse() { none() }
+
+  PhiNode asPhi() { none() }
+
+  abstract Location getLocation();
+}
+
+class DefOrUse extends TDefOrUse, SsaDefOrUse {
+  DefOrUseImpl defOrUse;
+
+  DefOrUse() { this = TDefOrUse(defOrUse) }
+
+  final override DefOrUseImpl asDefOrUse() { result = defOrUse }
+
+  final override Location getLocation() { result = defOrUse.getLocation() }
+
+  final SourceVariable getSourceVariable() { result = defOrUse.getSourceVariable() }
+
+  override string toString() { result = defOrUse.toString() }
+}
+
+class Phi extends TPhi, SsaDefOrUse {
+  PhiNode phi;
+
+  Phi() { this = TPhi(phi) }
+
+  final override PhiNode asPhi() { result = phi }
+
+  final override Location getLocation() { result = phi.getBasicBlock().getLocation() }
+
+  override string toString() { result = "Phi" }
+}
+
+class UseOrPhi extends SsaDefOrUse {
+  UseOrPhi() {
+    this.asDefOrUse() instanceof UseImpl
+    or
+    this instanceof Phi
+  }
+
+  final override Location getLocation() {
+    result = this.asDefOrUse().getLocation() or result = this.(Phi).getLocation()
+  }
+}
+
+class Def extends DefOrUse {
+  override DefImpl defOrUse;
+
+  Operand getAddressOperand() { result = defOrUse.getAddressOperand() }
+
+  Instruction getAddress() { result = this.getAddressOperand().getDef() }
+
+  /**
+   * This predicate ensures that joins go from `defOrUse` to the result
+   * instead of the other way around.
+   */
+  pragma[inline]
+  int getIndirectionIndex() {
+    pragma[only_bind_into](result) = pragma[only_bind_out](defOrUse).getIndirectionIndex()
+  }
+
+  Instruction getDefiningInstruction() { result = defOrUse.getDefiningInstruction() }
+}
+
+private module SsaImpl = SsaImplCommon::Make<SsaInput>;
+
+class PhiNode = SsaImpl::PhiNode;
+
+class Definition = SsaImpl::Definition;
+
+import SsaCached

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/SsaInternalsCommon.qll

@@ -0,0 +1,270 @@
+import cpp as Cpp
+import semmle.code.cpp.ir.IR
+import semmle.code.cpp.ir.internal.IRCppLanguage
+private import semmle.code.cpp.ir.implementation.raw.internal.SideEffects as SideEffects
+private import DataFlowImplCommon as DataFlowImplCommon
+private import DataFlowUtil
+
+/**
+ * Holds if `operand` is an operand that is not used by the dataflow library.
+ * Ignored operands are not recognizd as uses by SSA, and they don't have a
+ * corresponding `(Indirect)OperandNode`.
+ */
+predicate ignoreOperand(Operand operand) {
+  operand = any(Instruction instr | ignoreInstruction(instr)).getAnOperand() or
+  operand = any(Instruction instr | ignoreInstruction(instr)).getAUse() or
+  operand instanceof MemoryOperand
+}
+
+/**
+ * Holds if `instr` is an instruction that is not used by the dataflow library.
+ * Ignored instructions are not recognized as reads/writes by SSA, and they
+ * don't have a corresponding `(Indirect)InstructionNode`.
+ */
+predicate ignoreInstruction(Instruction instr) {
+  DataFlowImplCommon::forceCachingInSameStage() and
+  (
+    instr instanceof WriteSideEffectInstruction or
+    instr instanceof PhiInstruction or
+    instr instanceof ReadSideEffectInstruction or
+    instr instanceof ChiInstruction or
+    instr instanceof InitializeIndirectionInstruction
+  )
+}
+
+/**
+ * Gets the C++ type of `this` in the member function `f`.
+ * The result is a glvalue if `isGLValue` is true, and
+ * a prvalue if `isGLValue` is false.
+ */
+bindingset[isGLValue]
+private CppType getThisType(Cpp::MemberFunction f, boolean isGLValue) {
+  result.hasType(f.getTypeOfThis(), isGLValue)
+}
+
+/**
+ * Gets the C++ type of the instruction `i`.
+ *
+ * This is equivalent to `i.getResultLanguageType()` with the exception
+ * of instructions that directly references a `this` IRVariable. In this
+ * case, `i.getResultLanguageType()` gives an unknown type, whereas the
+ * predicate gives the expected type (i.e., a potentially cv-qualified
+ * type `A*` where `A` is the declaring type of the member function that
+ * contains `i`).
+ */
+cached
+CppType getResultLanguageType(Instruction i) {
+  if i.(VariableAddressInstruction).getIRVariable() instanceof IRThisVariable
+  then
+    if i.isGLValue()
+    then result = getThisType(i.getEnclosingFunction(), true)
+    else result = getThisType(i.getEnclosingFunction(), false)
+  else result = i.getResultLanguageType()
+}
+
+/**
+ * Gets the C++ type of the operand `operand`.
+ * This is equivalent to the type of the operand's defining instruction.
+ *
+ * See `getResultLanguageType` for a description of this behavior.
+ */
+CppType getLanguageType(Operand operand) { result = getResultLanguageType(operand.getDef()) }
+
+/**
+ * Gets the maximum number of indirections a glvalue of type `type` can have.
+ * For example:
+ * - If `type = int`, the result is 1
+ * - If `type = MyStruct`, the result is 1
+ * - If `type = char*`, the result is 2
+ */
+int getMaxIndirectionsForType(Type type) {
+  result = countIndirectionsForCppType(getTypeForGLValue(type))
+}
+
+/**
+ * Gets the maximum number of indirections a value of type `type` can have.
+ *
+ * Note that this predicate is intended to be called on unspecified types
+ * (i.e., `countIndirections(e.getUnspecifiedType())`).
+ */
+private int countIndirections(Type t) {
+  result =
+    1 +
+      countIndirections([t.(Cpp::PointerType).getBaseType(), t.(Cpp::ReferenceType).getBaseType()])
+  or
+  not t instanceof Cpp::PointerType and
+  not t instanceof Cpp::ReferenceType and
+  result = 0
+}
+
+/**
+ * Gets the maximum number of indirections a value of C++
+ * type `langType` can have.
+ */
+int countIndirectionsForCppType(LanguageType langType) {
+  exists(Type type | langType.hasType(type, true) |
+    result = 1 + countIndirections(type.getUnspecifiedType())
+  )
+  or
+  exists(Type type | langType.hasType(type, false) |
+    result = countIndirections(type.getUnspecifiedType())
+  )
+}
+
+/**
+ * A `CallInstruction` that calls an allocation function such
+ * as `malloc` or `operator new`.
+ */
+class AllocationInstruction extends CallInstruction {
+  AllocationInstruction() { this.getStaticCallTarget() instanceof Cpp::AllocationFunction }
+}
+
+/**
+ * Holds if `i` is a base instruction that starts a sequence of uses
+ * of some variable that SSA can handle.
+ *
+ * This is either when `i` is a `VariableAddressInstruction` or when
+ * `i` is a fresh allocation produced by an `AllocationInstruction`.
+ */
+private predicate isSourceVariableBase(Instruction i) {
+  i instanceof VariableAddressInstruction or i instanceof AllocationInstruction
+}
+
+/**
+ * Holds if the value pointed to by `operand` can potentially be
+ * modified be the caller.
+ */
+predicate isModifiableByCall(ArgumentOperand operand) {
+  exists(CallInstruction call, int index, CppType type |
+    type = getLanguageType(operand) and
+    call.getArgumentOperand(index) = operand and
+    if index = -1
+    then not call.getStaticCallTarget() instanceof Cpp::ConstMemberFunction
+    else not SideEffects::isConstPointerLike(any(Type t | type.hasType(t, _)))
+  )
+}
+
+cached
+private module Cached {
+  /**
+   * Holds if `op` is a use of an SSA variable rooted at `base` with `ind` number
+   * of indirections.
+   *
+   * `certain` is `true` if the operand is guaranteed to read the variable, and
+   * `indirectionIndex` specifies the number of loads required to read the variable.
+   */
+  cached
+  predicate isUse(boolean certain, Operand op, Instruction base, int ind, int indirectionIndex) {
+    not ignoreOperand(op) and
+    certain = true and
+    exists(LanguageType type, int m, int ind0 |
+      type = getLanguageType(op) and
+      m = countIndirectionsForCppType(type) and
+      isUseImpl(op, base, ind0) and
+      ind = ind0 + [0 .. m] and
+      indirectionIndex = ind - ind0
+    )
+  }
+
+  /**
+   * Holds if `operand` is a use of an SSA variable rooted at `base`, and the
+   * path from `base` to `operand` passes through `ind` load-like instructions.
+   */
+  private predicate isUseImpl(Operand operand, Instruction base, int ind) {
+    DataFlowImplCommon::forceCachingInSameStage() and
+    ind = 0 and
+    operand.getDef() = base and
+    isSourceVariableBase(base)
+    or
+    exists(Operand mid, Instruction instr |
+      isUseImpl(mid, base, ind) and
+      instr = operand.getDef() and
+      conversionFlow(mid, instr, false)
+    )
+    or
+    exists(int ind0 |
+      isUseImpl(operand.getDef().(LoadInstruction).getSourceAddressOperand(), base, ind0)
+      or
+      isUseImpl(operand.getDef().(InitializeParameterInstruction).getAnOperand(), base, ind0)
+    |
+      ind0 = ind - 1
+    )
+  }
+
+  /**
+   * Holds if `address` is an address of an SSA variable rooted at `base`,
+   * and `instr` is a definition of the SSA variable with `ind` number of indirections.
+   *
+   * `certain` is `true` if `instr` is guaranteed to write to the variable, and
+   * `indirectionIndex` specifies the number of loads required to read the variable
+   * after the write operation.
+   */
+  cached
+  predicate isDef(
+    boolean certain, Instruction instr, Operand address, Instruction base, int ind,
+    int indirectionIndex
+  ) {
+    certain = true and
+    exists(int ind0, CppType type, int m |
+      address =
+        [
+          instr.(StoreInstruction).getDestinationAddressOperand(),
+          instr.(InitializeParameterInstruction).getAnOperand(),
+          instr.(InitializeDynamicAllocationInstruction).getAllocationAddressOperand(),
+          instr.(UninitializedInstruction).getAnOperand()
+        ]
+    |
+      isDefImpl(address, base, ind0) and
+      type = getLanguageType(address) and
+      m = countIndirectionsForCppType(type) and
+      ind = ind0 + [1 .. m] and
+      indirectionIndex = ind - (ind0 + 1)
+    )
+  }
+
+  /**
+   * Holds if `address` is a use of an SSA variable rooted at `base`, and the
+   * path from `base` to `address` passes through `ind` load-like instructions.
+   *
+   * Note: Unlike `isUseImpl`, this predicate recurses through pointer-arithmetic
+   * instructions.
+   */
+  private predicate isDefImpl(Operand address, Instruction base, int ind) {
+    DataFlowImplCommon::forceCachingInSameStage() and
+    ind = 0 and
+    address.getDef() = base and
+    isSourceVariableBase(base)
+    or
+    exists(Operand mid, Instruction instr |
+      isDefImpl(mid, base, ind) and
+      instr = address.getDef() and
+      conversionFlow(mid, instr, _)
+    )
+    or
+    exists(int ind0 |
+      isDefImpl(address.getDef().(LoadInstruction).getSourceAddressOperand(), base, ind0)
+      or
+      isDefImpl(address.getDef().(InitializeParameterInstruction).getAnOperand(), base, ind0)
+    |
+      ind0 = ind - 1
+    )
+  }
+}
+
+import Cached
+
+/**
+ * Inputs to the shared SSA library's parameterized module that is shared
+ * between the SSA pruning stage, and the final SSA stage.
+ */
+module InputSigCommon {
+  class BasicBlock = IRBlock;
+
+  BasicBlock getImmediateBasicBlockDominator(BasicBlock bb) { result.immediatelyDominates(bb) }
+
+  BasicBlock getABasicBlockSuccessor(BasicBlock bb) { result = bb.getASuccessor() }
+
+  class ExitBasicBlock extends IRBlock {
+    ExitBasicBlock() { this.getLastInstruction() instanceof ExitFunctionInstruction }
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/TaintTrackingUtil.qll

@@ -0,0 +1,208 @@
+private import semmle.code.cpp.ir.IR
+private import experimental.semmle.code.cpp.ir.dataflow.DataFlow
+private import ModelUtil
+private import semmle.code.cpp.models.interfaces.DataFlow
+private import semmle.code.cpp.models.interfaces.SideEffect
+private import DataFlowUtil
+private import DataFlowPrivate
+private import semmle.code.cpp.models.Models
+
+/**
+ * Holds if taint propagates from `nodeFrom` to `nodeTo` in exactly one local
+ * (intra-procedural) step.
+ */
+predicate localTaintStep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
+  DataFlow::localFlowStep(nodeFrom, nodeTo)
+  or
+  localAdditionalTaintStep(nodeFrom, nodeTo)
+}
+
+/**
+ * Holds if taint can flow in one local step from `nodeFrom` to `nodeTo` excluding
+ * local data flow steps. That is, `nodeFrom` and `nodeTo` are likely to represent
+ * different objects.
+ */
+cached
+predicate localAdditionalTaintStep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
+  operandToInstructionTaintStep(nodeFrom.asOperand(), nodeTo.asInstruction())
+  or
+  modeledTaintStep(nodeFrom, nodeTo)
+  or
+  // Flow from `op` to `*op`.
+  exists(Operand operand, int indirectionIndex |
+    nodeHasOperand(nodeFrom, operand, indirectionIndex) and
+    nodeHasOperand(nodeTo, operand, indirectionIndex - 1)
+  )
+  or
+  // Flow from `instr` to `*instr`.
+  exists(Instruction instr, int indirectionIndex |
+    nodeHasInstruction(nodeFrom, instr, indirectionIndex) and
+    nodeHasInstruction(nodeTo, instr, indirectionIndex - 1)
+  )
+  or
+  // Flow from (the indirection of) an operand of a pointer arithmetic instruction to the
+  // indirection of the pointer arithmetic instruction. This provides flow from `source`
+  // in `x[source]` to the result of the associated load instruction.
+  exists(PointerArithmeticInstruction pai, int indirectionIndex |
+    nodeHasOperand(nodeFrom, pai.getAnOperand(), pragma[only_bind_into](indirectionIndex)) and
+    hasInstructionAndIndex(nodeTo, pai, indirectionIndex + 1)
+  )
+}
+
+/**
+ * Holds if taint propagates from `nodeFrom` to `nodeTo` in exactly one local
+ * (intra-procedural) step.
+ */
+private predicate operandToInstructionTaintStep(Operand opFrom, Instruction instrTo) {
+  // Taint can flow through expressions that alter the value but preserve
+  // more than one bit of it _or_ expressions that follow data through
+  // pointer indirections.
+  instrTo.getAnOperand() = opFrom and
+  (
+    instrTo instanceof ArithmeticInstruction
+    or
+    instrTo instanceof BitwiseInstruction
+    or
+    instrTo instanceof PointerArithmeticInstruction
+  )
+  or
+  // The `CopyInstruction` case is also present in non-taint data flow, but
+  // that uses `getDef` rather than `getAnyDef`. For taint, we want flow
+  // from a definition of `myStruct` to a `myStruct.myField` expression.
+  instrTo.(LoadInstruction).getSourceAddressOperand() = opFrom
+  or
+  // Unary instructions tend to preserve enough information in practice that we
+  // want taint to flow through.
+  // The exception is `FieldAddressInstruction`. Together with the rules below for
+  // `LoadInstruction`s and `ChiInstruction`s, flow through `FieldAddressInstruction`
+  // could cause flow into one field to come out an unrelated field.
+  // This would happen across function boundaries, where the IR would not be able to
+  // match loads to stores.
+  instrTo.(UnaryInstruction).getUnaryOperand() = opFrom and
+  (
+    not instrTo instanceof FieldAddressInstruction
+    or
+    instrTo.(FieldAddressInstruction).getField().getDeclaringType() instanceof Union
+  )
+}
+
+/**
+ * Holds if taint may propagate from `source` to `sink` in zero or more local
+ * (intra-procedural) steps.
+ */
+pragma[inline]
+predicate localTaint(DataFlow::Node source, DataFlow::Node sink) { localTaintStep*(source, sink) }
+
+/**
+ * Holds if taint can flow from `i1` to `i2` in zero or more
+ * local (intra-procedural) steps.
+ */
+pragma[inline]
+predicate localInstructionTaint(Instruction i1, Instruction i2) {
+  localTaint(DataFlow::instructionNode(i1), DataFlow::instructionNode(i2))
+}
+
+/**
+ * Holds if taint can flow from `e1` to `e2` in zero or more
+ * local (intra-procedural) steps.
+ */
+pragma[inline]
+predicate localExprTaint(Expr e1, Expr e2) {
+  localTaint(DataFlow::exprNode(e1), DataFlow::exprNode(e2))
+}
+
+/**
+ * Holds if the additional step from `src` to `sink` should be included in all
+ * global taint flow configurations.
+ */
+predicate defaultAdditionalTaintStep(DataFlow::Node src, DataFlow::Node sink) {
+  localAdditionalTaintStep(src, sink)
+}
+
+/**
+ * Holds if default `TaintTracking::Configuration`s should allow implicit reads
+ * of `c` at sinks and inputs to additional taint steps.
+ */
+bindingset[node]
+predicate defaultImplicitTaintRead(DataFlow::Node node, DataFlow::Content c) { none() }
+
+/**
+ * Holds if `node` should be a sanitizer in all global taint flow configurations
+ * but not in local taint.
+ */
+predicate defaultTaintSanitizer(DataFlow::Node node) { none() }
+
+/**
+ * Holds if taint can flow from `instrIn` to `instrOut` through a call to a
+ * modeled function.
+ */
+predicate modeledTaintStep(DataFlow::Node nodeIn, DataFlow::Node nodeOut) {
+  // Normal taint steps
+  exists(CallInstruction call, TaintFunction func, FunctionInput modelIn, FunctionOutput modelOut |
+    call.getStaticCallTarget() = func and
+    func.hasTaintFlow(modelIn, modelOut)
+  |
+    (
+      nodeIn = callInput(call, modelIn)
+      or
+      exists(int n |
+        modelIn.isParameterDerefOrQualifierObject(n) and
+        if n = -1
+        then nodeIn = callInput(call, any(InQualifierAddress inQualifier))
+        else nodeIn = callInput(call, any(InParameter inParam | inParam.getIndex() = n))
+      )
+    ) and
+    nodeOut = callOutput(call, modelOut)
+    or
+    exists(int d |
+      nodeIn = callInput(call, modelIn, d)
+      or
+      exists(int n |
+        d = 1 and
+        modelIn.isParameterDerefOrQualifierObject(n) and
+        if n = -1
+        then nodeIn = callInput(call, any(InQualifierAddress inQualifier))
+        else nodeIn = callInput(call, any(InParameter inParam | inParam.getIndex() = n))
+      )
+    |
+      call.getStaticCallTarget() = func and
+      func.hasTaintFlow(modelIn, modelOut) and
+      nodeOut = callOutput(call, modelOut, d)
+    )
+  )
+  or
+  // Taint flow from one argument to another and data flow from an argument to a
+  // return value. This happens in functions like `strcat` and `memcpy`. We
+  // could model this flow in two separate steps, but that would add reverse
+  // flow from the write side-effect to the call instruction, which may not be
+  // desirable.
+  exists(
+    CallInstruction call, Function func, FunctionInput modelIn, OutParameterDeref modelMidOut,
+    int indexMid, InParameter modelMidIn, OutReturnValue modelOut
+  |
+    nodeIn = callInput(call, modelIn) and
+    nodeOut = callOutput(call, modelOut) and
+    call.getStaticCallTarget() = func and
+    func.(TaintFunction).hasTaintFlow(modelIn, modelMidOut) and
+    func.(DataFlowFunction).hasDataFlow(modelMidIn, modelOut) and
+    modelMidOut.isParameterDeref(indexMid) and
+    modelMidIn.isParameter(indexMid)
+  )
+  or
+  // Taint flow from a pointer argument to an output, when the model specifies flow from the deref
+  // to that output, but the deref is not modeled in the IR for the caller.
+  exists(
+    CallInstruction call, DataFlow::SideEffectOperandNode indirectArgument, Function func,
+    FunctionInput modelIn, FunctionOutput modelOut
+  |
+    indirectArgument = callInput(call, modelIn) and
+    indirectArgument.getAddressOperand() = nodeIn.asOperand() and
+    call.getStaticCallTarget() = func and
+    (
+      func.(DataFlowFunction).hasDataFlow(modelIn, modelOut)
+      or
+      func.(TaintFunction).hasTaintFlow(modelIn, modelOut)
+    ) and
+    nodeOut = callOutput(call, modelOut)
+  )
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/ssa0/SsaInternals.qll

@@ -0,0 +1,314 @@
+/**
+ * This module defines an initial SSA pruning stage that doesn't take
+ * indirections into account.
+ */
+
+private import codeql.ssa.Ssa as SsaImplCommon
+private import semmle.code.cpp.ir.IR
+private import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowImplCommon as DataFlowImplCommon
+private import semmle.code.cpp.models.interfaces.Allocation as Alloc
+private import semmle.code.cpp.models.interfaces.DataFlow as DataFlow
+private import semmle.code.cpp.ir.implementation.raw.internal.SideEffects as SideEffects
+private import semmle.code.cpp.ir.internal.IRCppLanguage
+private import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowPrivate
+private import experimental.semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
+private import experimental.semmle.code.cpp.ir.dataflow.internal.SsaInternalsCommon
+
+private module SourceVariables {
+  newtype TBaseSourceVariable =
+    // Each IR variable gets its own source variable
+    TBaseIRVariable(IRVariable var) or
+    // Each allocation gets its own source variable
+    TBaseCallVariable(AllocationInstruction call)
+
+  abstract class BaseSourceVariable extends TBaseSourceVariable {
+    abstract string toString();
+
+    abstract DataFlowType getType();
+  }
+
+  class BaseIRVariable extends BaseSourceVariable, TBaseIRVariable {
+    IRVariable var;
+
+    IRVariable getIRVariable() { result = var }
+
+    BaseIRVariable() { this = TBaseIRVariable(var) }
+
+    override string toString() { result = var.toString() }
+
+    override DataFlowType getType() { result = var.getType() }
+  }
+
+  class BaseCallVariable extends BaseSourceVariable, TBaseCallVariable {
+    AllocationInstruction call;
+
+    BaseCallVariable() { this = TBaseCallVariable(call) }
+
+    AllocationInstruction getCallInstruction() { result = call }
+
+    override string toString() { result = call.toString() }
+
+    override DataFlowType getType() { result = call.getResultType() }
+  }
+
+  private newtype TSourceVariable =
+    TSourceIRVariable(BaseIRVariable baseVar) or
+    TCallVariable(AllocationInstruction call)
+
+  abstract class SourceVariable extends TSourceVariable {
+    abstract string toString();
+
+    abstract BaseSourceVariable getBaseVariable();
+  }
+
+  class SourceIRVariable extends SourceVariable, TSourceIRVariable {
+    BaseIRVariable var;
+
+    SourceIRVariable() { this = TSourceIRVariable(var) }
+
+    IRVariable getIRVariable() { result = var.getIRVariable() }
+
+    override BaseIRVariable getBaseVariable() { result.getIRVariable() = this.getIRVariable() }
+
+    override string toString() { result = this.getIRVariable().toString() }
+  }
+
+  class CallVariable extends SourceVariable, TCallVariable {
+    AllocationInstruction call;
+
+    CallVariable() { this = TCallVariable(call) }
+
+    AllocationInstruction getCall() { result = call }
+
+    override BaseCallVariable getBaseVariable() { result.getCallInstruction() = call }
+
+    override string toString() { result = "Call" }
+  }
+}
+
+import SourceVariables
+
+private newtype TDefOrUseImpl =
+  TDefImpl(Operand address) { isDef(_, _, address, _, _, _) } or
+  TUseImpl(Operand operand) {
+    isUse(_, operand, _, _, _) and
+    not isDef(_, _, operand, _, _, _)
+  }
+
+abstract private class DefOrUseImpl extends TDefOrUseImpl {
+  /** Gets a textual representation of this element. */
+  abstract string toString();
+
+  /** Gets the block of this definition or use. */
+  abstract IRBlock getBlock();
+
+  /** Holds if this definition or use has index `index` in block `block`. */
+  abstract predicate hasIndexInBlock(IRBlock block, int index);
+
+  final predicate hasIndexInBlock(IRBlock block, int index, SourceVariable sv) {
+    this.hasIndexInBlock(block, index) and
+    sv = this.getSourceVariable()
+  }
+
+  /** Gets the location of this element. */
+  abstract Cpp::Location getLocation();
+
+  abstract Instruction getBase();
+
+  final BaseSourceVariable getBaseSourceVariable() {
+    exists(IRVariable var |
+      result.(BaseIRVariable).getIRVariable() = var and
+      instructionHasIRVariable(this.getBase(), var)
+    )
+    or
+    result.(BaseCallVariable).getCallInstruction() = this.getBase()
+  }
+
+  /** Gets the variable that is defined or used. */
+  final SourceVariable getSourceVariable() {
+    exists(BaseSourceVariable v |
+      sourceVariableHasBaseAndIndex(result, v) and
+      defOrUseHasSourceVariable(this, v)
+    )
+  }
+}
+
+pragma[noinline]
+private predicate instructionHasIRVariable(VariableAddressInstruction vai, IRVariable var) {
+  vai.getIRVariable() = var
+}
+
+private predicate defOrUseHasSourceVariable(DefOrUseImpl defOrUse, BaseSourceVariable bv) {
+  defHasSourceVariable(defOrUse, bv)
+  or
+  useHasSourceVariable(defOrUse, bv)
+}
+
+pragma[noinline]
+private predicate defHasSourceVariable(DefImpl def, BaseSourceVariable bv) {
+  bv = def.getBaseSourceVariable()
+}
+
+pragma[noinline]
+private predicate useHasSourceVariable(UseImpl use, BaseSourceVariable bv) {
+  bv = use.getBaseSourceVariable()
+}
+
+pragma[noinline]
+private predicate sourceVariableHasBaseAndIndex(SourceVariable v, BaseSourceVariable bv) {
+  v.getBaseVariable() = bv
+}
+
+class DefImpl extends DefOrUseImpl, TDefImpl {
+  Operand address;
+
+  DefImpl() { this = TDefImpl(address) }
+
+  override Instruction getBase() { isDef(_, _, address, result, _, _) }
+
+  Operand getAddressOperand() { result = address }
+
+  Instruction getDefiningInstruction() { isDef(_, result, address, _, _, _) }
+
+  override string toString() { result = address.toString() }
+
+  override IRBlock getBlock() { result = this.getDefiningInstruction().getBlock() }
+
+  override Cpp::Location getLocation() { result = this.getDefiningInstruction().getLocation() }
+
+  final override predicate hasIndexInBlock(IRBlock block, int index) {
+    this.getDefiningInstruction() = block.getInstruction(index)
+  }
+
+  predicate isCertain() { isDef(true, _, address, _, _, _) }
+}
+
+class UseImpl extends DefOrUseImpl, TUseImpl {
+  Operand operand;
+
+  UseImpl() { this = TUseImpl(operand) }
+
+  Operand getOperand() { result = operand }
+
+  override string toString() { result = operand.toString() }
+
+  final override predicate hasIndexInBlock(IRBlock block, int index) {
+    operand.getUse() = block.getInstruction(index)
+  }
+
+  final override IRBlock getBlock() { result = operand.getUse().getBlock() }
+
+  final override Cpp::Location getLocation() { result = operand.getLocation() }
+
+  override Instruction getBase() { isUse(_, operand, result, _, _) }
+
+  predicate isCertain() { isUse(true, operand, _, _, _) }
+}
+
+private module SsaInput implements SsaImplCommon::InputSig {
+  import InputSigCommon
+  import SourceVariables
+
+  /**
+   * Holds if the `i`'th write in block `bb` writes to the variable `v`.
+   * `certain` is `true` if the write is guaranteed to overwrite the entire variable.
+   */
+  predicate variableWrite(IRBlock bb, int i, SourceVariable v, boolean certain) {
+    DataFlowImplCommon::forceCachingInSameStage() and
+    exists(DefImpl def | def.hasIndexInBlock(bb, i, v) |
+      if def.isCertain() then certain = true else certain = false
+    )
+  }
+
+  /**
+   * Holds if the `i`'th read in block `bb` reads to the variable `v`.
+   * `certain` is `true` if the read is guaranteed.
+   */
+  predicate variableRead(IRBlock bb, int i, SourceVariable v, boolean certain) {
+    exists(UseImpl use | use.hasIndexInBlock(bb, i, v) |
+      if use.isCertain() then certain = true else certain = false
+    )
+  }
+}
+
+private newtype TSsaDefOrUse =
+  TDefOrUse(DefOrUseImpl defOrUse) {
+    defOrUse instanceof UseImpl
+    or
+    // If `defOrUse` is a definition we only include it if the
+    // SSA library concludes that it's live after the write.
+    exists(Definition def, SourceVariable sv, IRBlock bb, int i |
+      def.definesAt(sv, bb, i) and
+      defOrUse.(DefImpl).hasIndexInBlock(bb, i, sv)
+    )
+  } or
+  TPhi(PhiNode phi)
+
+abstract private class SsaDefOrUse extends TSsaDefOrUse {
+  string toString() { result = "SsaDefOrUse" }
+
+  DefOrUseImpl asDefOrUse() { none() }
+
+  PhiNode asPhi() { none() }
+
+  abstract Location getLocation();
+}
+
+class DefOrUse extends TDefOrUse, SsaDefOrUse {
+  DefOrUseImpl defOrUse;
+
+  DefOrUse() { this = TDefOrUse(defOrUse) }
+
+  final override DefOrUseImpl asDefOrUse() { result = defOrUse }
+
+  final override Location getLocation() { result = defOrUse.getLocation() }
+
+  final SourceVariable getSourceVariable() { result = defOrUse.getSourceVariable() }
+}
+
+class Phi extends TPhi, SsaDefOrUse {
+  PhiNode phi;
+
+  Phi() { this = TPhi(phi) }
+
+  final override PhiNode asPhi() { result = phi }
+
+  final override Location getLocation() { result = phi.getBasicBlock().getLocation() }
+}
+
+class UseOrPhi extends SsaDefOrUse {
+  UseOrPhi() {
+    this.asDefOrUse() instanceof UseImpl
+    or
+    this instanceof Phi
+  }
+
+  final override Location getLocation() {
+    result = this.asDefOrUse().getLocation() or result = this.(Phi).getLocation()
+  }
+
+  override string toString() {
+    result = this.asDefOrUse().toString()
+    or
+    this instanceof Phi and
+    result = "Phi"
+  }
+}
+
+class Def extends DefOrUse {
+  override DefImpl defOrUse;
+
+  Operand getAddressOperand() { result = defOrUse.getAddressOperand() }
+
+  Instruction getAddress() { result = this.getAddressOperand().getDef() }
+
+  Instruction getDefiningInstruction() { result = defOrUse.getDefiningInstruction() }
+
+  override string toString() { result = this.asDefOrUse().toString() + " (def)" }
+}
+
+private module SsaImpl = SsaImplCommon::Make<SsaInput>;
+
+class PhiNode = SsaImpl::PhiNode;
+
+class Definition = SsaImpl::Definition;

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking1/TaintTrackingImpl.qll

@@ -172,7 +172,12 @@ abstract class Configuration extends DataFlow::Configuration {
   }
 
   override predicate allowImplicitRead(DataFlow::Node node, DataFlow::ContentSet c) {
-    (this.isSink(node) or this.isAdditionalTaintStep(node, _)) and
+    (
+      this.isSink(node) or
+      this.isSink(node, _) or
+      this.isAdditionalTaintStep(node, _) or
+      this.isAdditionalTaintStep(node, _, _, _)
+    ) and
     defaultImplicitTaintRead(node, c)
   }
 

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking1/TaintTrackingParameter.qll

@@ -0,0 +1,5 @@
+import experimental.semmle.code.cpp.ir.dataflow.internal.TaintTrackingUtil as Public
+
+module Private {
+  import experimental.semmle.code.cpp.ir.dataflow.DataFlow::DataFlow as DataFlow
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking2/TaintTrackingImpl.qll

@@ -0,0 +1,191 @@
+/**
+ * Provides an implementation of global (interprocedural) taint tracking.
+ * This file re-exports the local (intraprocedural) taint-tracking analysis
+ * from `TaintTrackingParameter::Public` and adds a global analysis, mainly
+ * exposed through the `Configuration` class. For some languages, this file
+ * exists in several identical copies, allowing queries to use multiple
+ * `Configuration` classes that depend on each other without introducing
+ * mutual recursion among those configurations.
+ */
+
+import TaintTrackingParameter::Public
+private import TaintTrackingParameter::Private
+
+/**
+ * A configuration of interprocedural taint tracking analysis. This defines
+ * sources, sinks, and any other configurable aspect of the analysis. Each
+ * use of the taint tracking library must define its own unique extension of
+ * this abstract class.
+ *
+ * A taint-tracking configuration is a special data flow configuration
+ * (`DataFlow::Configuration`) that allows for flow through nodes that do not
+ * necessarily preserve values but are still relevant from a taint tracking
+ * perspective. (For example, string concatenation, where one of the operands
+ * is tainted.)
+ *
+ * To create a configuration, extend this class with a subclass whose
+ * characteristic predicate is a unique singleton string. For example, write
+ *
+ * ```ql
+ * class MyAnalysisConfiguration extends TaintTracking::Configuration {
+ *   MyAnalysisConfiguration() { this = "MyAnalysisConfiguration" }
+ *   // Override `isSource` and `isSink`.
+ *   // Optionally override `isSanitizer`.
+ *   // Optionally override `isSanitizerIn`.
+ *   // Optionally override `isSanitizerOut`.
+ *   // Optionally override `isSanitizerGuard`.
+ *   // Optionally override `isAdditionalTaintStep`.
+ * }
+ * ```
+ *
+ * Then, to query whether there is flow between some `source` and `sink`,
+ * write
+ *
+ * ```ql
+ * exists(MyAnalysisConfiguration cfg | cfg.hasFlow(source, sink))
+ * ```
+ *
+ * Multiple configurations can coexist, but it is unsupported to depend on
+ * another `TaintTracking::Configuration` or a `DataFlow::Configuration` in the
+ * overridden predicates that define sources, sinks, or additional steps.
+ * Instead, the dependency should go to a `TaintTracking2::Configuration` or a
+ * `DataFlow2::Configuration`, `DataFlow3::Configuration`, etc.
+ */
+abstract class Configuration extends DataFlow::Configuration {
+  bindingset[this]
+  Configuration() { any() }
+
+  /**
+   * Holds if `source` is a relevant taint source.
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSource(DataFlow::Node source) { none() }
+
+  /**
+   * Holds if `source` is a relevant taint source with the given initial
+   * `state`.
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSource(DataFlow::Node source, DataFlow::FlowState state) { none() }
+
+  /**
+   * Holds if `sink` is a relevant taint sink
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSink(DataFlow::Node sink) { none() }
+
+  /**
+   * Holds if `sink` is a relevant taint sink accepting `state`.
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSink(DataFlow::Node sink, DataFlow::FlowState state) { none() }
+
+  /** Holds if the node `node` is a taint sanitizer. */
+  predicate isSanitizer(DataFlow::Node node) { none() }
+
+  final override predicate isBarrier(DataFlow::Node node) {
+    this.isSanitizer(node) or
+    defaultTaintSanitizer(node)
+  }
+
+  /**
+   * Holds if the node `node` is a taint sanitizer when the flow state is
+   * `state`.
+   */
+  predicate isSanitizer(DataFlow::Node node, DataFlow::FlowState state) { none() }
+
+  final override predicate isBarrier(DataFlow::Node node, DataFlow::FlowState state) {
+    this.isSanitizer(node, state)
+  }
+
+  /** Holds if taint propagation into `node` is prohibited. */
+  predicate isSanitizerIn(DataFlow::Node node) { none() }
+
+  final override predicate isBarrierIn(DataFlow::Node node) { this.isSanitizerIn(node) }
+
+  /** Holds if taint propagation out of `node` is prohibited. */
+  predicate isSanitizerOut(DataFlow::Node node) { none() }
+
+  final override predicate isBarrierOut(DataFlow::Node node) { this.isSanitizerOut(node) }
+
+  /**
+   * DEPRECATED: Use `isSanitizer` and `BarrierGuard` module instead.
+   *
+   * Holds if taint propagation through nodes guarded by `guard` is prohibited.
+   */
+  deprecated predicate isSanitizerGuard(DataFlow::BarrierGuard guard) { none() }
+
+  deprecated final override predicate isBarrierGuard(DataFlow::BarrierGuard guard) {
+    this.isSanitizerGuard(guard)
+  }
+
+  /**
+   * DEPRECATED: Use `isSanitizer` and `BarrierGuard` module instead.
+   *
+   * Holds if taint propagation through nodes guarded by `guard` is prohibited
+   * when the flow state is `state`.
+   */
+  deprecated predicate isSanitizerGuard(DataFlow::BarrierGuard guard, DataFlow::FlowState state) {
+    none()
+  }
+
+  deprecated final override predicate isBarrierGuard(
+    DataFlow::BarrierGuard guard, DataFlow::FlowState state
+  ) {
+    this.isSanitizerGuard(guard, state)
+  }
+
+  /**
+   * Holds if taint may propagate from `node1` to `node2` in addition to the normal data-flow and taint steps.
+   */
+  predicate isAdditionalTaintStep(DataFlow::Node node1, DataFlow::Node node2) { none() }
+
+  final override predicate isAdditionalFlowStep(DataFlow::Node node1, DataFlow::Node node2) {
+    this.isAdditionalTaintStep(node1, node2) or
+    defaultAdditionalTaintStep(node1, node2)
+  }
+
+  /**
+   * Holds if taint may propagate from `node1` to `node2` in addition to the normal data-flow and taint steps.
+   * This step is only applicable in `state1` and updates the flow state to `state2`.
+   */
+  predicate isAdditionalTaintStep(
+    DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+    DataFlow::FlowState state2
+  ) {
+    none()
+  }
+
+  final override predicate isAdditionalFlowStep(
+    DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+    DataFlow::FlowState state2
+  ) {
+    this.isAdditionalTaintStep(node1, state1, node2, state2)
+  }
+
+  override predicate allowImplicitRead(DataFlow::Node node, DataFlow::ContentSet c) {
+    (
+      this.isSink(node) or
+      this.isSink(node, _) or
+      this.isAdditionalTaintStep(node, _) or
+      this.isAdditionalTaintStep(node, _, _, _)
+    ) and
+    defaultImplicitTaintRead(node, c)
+  }
+
+  /**
+   * Holds if taint may flow from `source` to `sink` for this configuration.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate hasFlow(DataFlow::Node source, DataFlow::Node sink) {
+    super.hasFlow(source, sink)
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking2/TaintTrackingParameter.qll

@@ -0,0 +1,5 @@
+import experimental.semmle.code.cpp.ir.dataflow.internal.TaintTrackingUtil as Public
+
+module Private {
+  import experimental.semmle.code.cpp.ir.dataflow.DataFlow2::DataFlow2 as DataFlow
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking3/TaintTrackingImpl.qll

@@ -0,0 +1,191 @@
+/**
+ * Provides an implementation of global (interprocedural) taint tracking.
+ * This file re-exports the local (intraprocedural) taint-tracking analysis
+ * from `TaintTrackingParameter::Public` and adds a global analysis, mainly
+ * exposed through the `Configuration` class. For some languages, this file
+ * exists in several identical copies, allowing queries to use multiple
+ * `Configuration` classes that depend on each other without introducing
+ * mutual recursion among those configurations.
+ */
+
+import TaintTrackingParameter::Public
+private import TaintTrackingParameter::Private
+
+/**
+ * A configuration of interprocedural taint tracking analysis. This defines
+ * sources, sinks, and any other configurable aspect of the analysis. Each
+ * use of the taint tracking library must define its own unique extension of
+ * this abstract class.
+ *
+ * A taint-tracking configuration is a special data flow configuration
+ * (`DataFlow::Configuration`) that allows for flow through nodes that do not
+ * necessarily preserve values but are still relevant from a taint tracking
+ * perspective. (For example, string concatenation, where one of the operands
+ * is tainted.)
+ *
+ * To create a configuration, extend this class with a subclass whose
+ * characteristic predicate is a unique singleton string. For example, write
+ *
+ * ```ql
+ * class MyAnalysisConfiguration extends TaintTracking::Configuration {
+ *   MyAnalysisConfiguration() { this = "MyAnalysisConfiguration" }
+ *   // Override `isSource` and `isSink`.
+ *   // Optionally override `isSanitizer`.
+ *   // Optionally override `isSanitizerIn`.
+ *   // Optionally override `isSanitizerOut`.
+ *   // Optionally override `isSanitizerGuard`.
+ *   // Optionally override `isAdditionalTaintStep`.
+ * }
+ * ```
+ *
+ * Then, to query whether there is flow between some `source` and `sink`,
+ * write
+ *
+ * ```ql
+ * exists(MyAnalysisConfiguration cfg | cfg.hasFlow(source, sink))
+ * ```
+ *
+ * Multiple configurations can coexist, but it is unsupported to depend on
+ * another `TaintTracking::Configuration` or a `DataFlow::Configuration` in the
+ * overridden predicates that define sources, sinks, or additional steps.
+ * Instead, the dependency should go to a `TaintTracking2::Configuration` or a
+ * `DataFlow2::Configuration`, `DataFlow3::Configuration`, etc.
+ */
+abstract class Configuration extends DataFlow::Configuration {
+  bindingset[this]
+  Configuration() { any() }
+
+  /**
+   * Holds if `source` is a relevant taint source.
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSource(DataFlow::Node source) { none() }
+
+  /**
+   * Holds if `source` is a relevant taint source with the given initial
+   * `state`.
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSource(DataFlow::Node source, DataFlow::FlowState state) { none() }
+
+  /**
+   * Holds if `sink` is a relevant taint sink
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSink(DataFlow::Node sink) { none() }
+
+  /**
+   * Holds if `sink` is a relevant taint sink accepting `state`.
+   *
+   * The smaller this predicate is, the faster `hasFlow()` will converge.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate isSink(DataFlow::Node sink, DataFlow::FlowState state) { none() }
+
+  /** Holds if the node `node` is a taint sanitizer. */
+  predicate isSanitizer(DataFlow::Node node) { none() }
+
+  final override predicate isBarrier(DataFlow::Node node) {
+    this.isSanitizer(node) or
+    defaultTaintSanitizer(node)
+  }
+
+  /**
+   * Holds if the node `node` is a taint sanitizer when the flow state is
+   * `state`.
+   */
+  predicate isSanitizer(DataFlow::Node node, DataFlow::FlowState state) { none() }
+
+  final override predicate isBarrier(DataFlow::Node node, DataFlow::FlowState state) {
+    this.isSanitizer(node, state)
+  }
+
+  /** Holds if taint propagation into `node` is prohibited. */
+  predicate isSanitizerIn(DataFlow::Node node) { none() }
+
+  final override predicate isBarrierIn(DataFlow::Node node) { this.isSanitizerIn(node) }
+
+  /** Holds if taint propagation out of `node` is prohibited. */
+  predicate isSanitizerOut(DataFlow::Node node) { none() }
+
+  final override predicate isBarrierOut(DataFlow::Node node) { this.isSanitizerOut(node) }
+
+  /**
+   * DEPRECATED: Use `isSanitizer` and `BarrierGuard` module instead.
+   *
+   * Holds if taint propagation through nodes guarded by `guard` is prohibited.
+   */
+  deprecated predicate isSanitizerGuard(DataFlow::BarrierGuard guard) { none() }
+
+  deprecated final override predicate isBarrierGuard(DataFlow::BarrierGuard guard) {
+    this.isSanitizerGuard(guard)
+  }
+
+  /**
+   * DEPRECATED: Use `isSanitizer` and `BarrierGuard` module instead.
+   *
+   * Holds if taint propagation through nodes guarded by `guard` is prohibited
+   * when the flow state is `state`.
+   */
+  deprecated predicate isSanitizerGuard(DataFlow::BarrierGuard guard, DataFlow::FlowState state) {
+    none()
+  }
+
+  deprecated final override predicate isBarrierGuard(
+    DataFlow::BarrierGuard guard, DataFlow::FlowState state
+  ) {
+    this.isSanitizerGuard(guard, state)
+  }
+
+  /**
+   * Holds if taint may propagate from `node1` to `node2` in addition to the normal data-flow and taint steps.
+   */
+  predicate isAdditionalTaintStep(DataFlow::Node node1, DataFlow::Node node2) { none() }
+
+  final override predicate isAdditionalFlowStep(DataFlow::Node node1, DataFlow::Node node2) {
+    this.isAdditionalTaintStep(node1, node2) or
+    defaultAdditionalTaintStep(node1, node2)
+  }
+
+  /**
+   * Holds if taint may propagate from `node1` to `node2` in addition to the normal data-flow and taint steps.
+   * This step is only applicable in `state1` and updates the flow state to `state2`.
+   */
+  predicate isAdditionalTaintStep(
+    DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+    DataFlow::FlowState state2
+  ) {
+    none()
+  }
+
+  final override predicate isAdditionalFlowStep(
+    DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+    DataFlow::FlowState state2
+  ) {
+    this.isAdditionalTaintStep(node1, state1, node2, state2)
+  }
+
+  override predicate allowImplicitRead(DataFlow::Node node, DataFlow::ContentSet c) {
+    (
+      this.isSink(node) or
+      this.isSink(node, _) or
+      this.isAdditionalTaintStep(node, _) or
+      this.isAdditionalTaintStep(node, _, _, _)
+    ) and
+    defaultImplicitTaintRead(node, c)
+  }
+
+  /**
+   * Holds if taint may flow from `source` to `sink` for this configuration.
+   */
+  // overridden to provide taint-tracking specific qldoc
+  override predicate hasFlow(DataFlow::Node source, DataFlow::Node sink) {
+    super.hasFlow(source, sink)
+  }
+}

cpp/ql/lib/experimental/semmle/code/cpp/ir/dataflow/internal/tainttracking3/TaintTrackingParameter.qll

@@ -0,0 +1,5 @@
+import experimental.semmle.code.cpp.ir.dataflow.internal.TaintTrackingUtil as Public
+
+module Private {
+  import experimental.semmle.code.cpp.ir.dataflow.DataFlow3::DataFlow3 as DataFlow
+}

cpp/ql/lib/experimental/semmle/code/cpp/rangeanalysis/Bound.qll

@@ -28,6 +28,10 @@ private newtype TBound =
       i.(LoadInstruction).getSourceAddress() instanceof FieldAddressInstruction
       or
       i.getAUse() instanceof ArgumentOperand
+      or
+      i instanceof PointerArithmeticInstruction
+      or
+      i.getAUse() instanceof AddressOperand
     )
   }
 
@@ -73,7 +77,7 @@ class ValueNumberBound extends Bound, TBoundValueNumber {
     this = TBoundValueNumber(valueNumber(result)) and delta = 0
   }
 
-  override string toString() { result = vn.getExampleInstruction().toString() }
+  override string toString() { result = "ValueNumberBound" }
 
   override Location getLocation() { result = vn.getLocation() }
 

cpp/ql/lib/experimental/semmle/code/cpp/semantic/SemanticExpr.qll

@@ -178,11 +178,11 @@ class SemRelationalExpr extends SemBinaryExpr {
 }
 
 class SemAddExpr extends SemBinaryExpr {
-  SemAddExpr() { opcode instanceof Opcode::Add }
+  SemAddExpr() { opcode instanceof Opcode::Add or opcode instanceof Opcode::PointerAdd }
 }
 
 class SemSubExpr extends SemBinaryExpr {
-  SemSubExpr() { opcode instanceof Opcode::Sub }
+  SemSubExpr() { opcode instanceof Opcode::Sub or opcode instanceof Opcode::PointerSub }
 }
 
 class SemMulExpr extends SemBinaryExpr {

cpp/ql/lib/experimental/semmle/code/cpp/semantic/SemanticExprSpecific.qll

@@ -7,6 +7,7 @@ private import semmle.code.cpp.ir.IR as IR
 private import Semantic
 private import experimental.semmle.code.cpp.rangeanalysis.Bound as IRBound
 private import semmle.code.cpp.controlflow.IRGuards as IRGuards
+private import semmle.code.cpp.ir.ValueNumbering
 
 module SemanticExprConfig {
   class Location = Cpp::Location;
@@ -112,34 +113,99 @@ module SemanticExprConfig {
 
   predicate hasDominanceInformation(BasicBlock block) { any() }
 
-  int getBasicBlockUniqueId(BasicBlock block) {
-    // REVIEW: `getDisplayIndex()` is not intended for use in real queries, but for now it's the
-    // best we can do because `equivalentRelation` won't accept a predicate whose parameters are IPA
-    // types.
-    result = block.getDisplayIndex()
+  private predicate id(Cpp::Locatable x, Cpp::Locatable y) { x = y }
+
+  private predicate idOf(Cpp::Locatable x, int y) = equivalenceRelation(id/2)(x, y)
+
+  int getBasicBlockUniqueId(BasicBlock block) { idOf(block.getFirstInstruction().getAst(), result) }
+
+  newtype TSsaVariable =
+    TSsaInstruction(IR::Instruction instr) { instr.hasMemoryResult() } or
+    TSsaOperand(IR::Operand op) { op.isDefinitionInexact() } or
+    TSsaPointerArithmeticGuard(IR::PointerArithmeticInstruction instr) {
+      exists(Guard g, IR::Operand use | use = instr.getAUse() |
+        g.comparesLt(use, _, _, _, _) or
+        g.comparesLt(_, use, _, _, _) or
+        g.comparesEq(use, _, _, _, _) or
+        g.comparesEq(_, use, _, _, _)
+      )
+    }
+
+  class SsaVariable extends TSsaVariable {
+    string toString() { none() }
+
+    Location getLocation() { none() }
+
+    IR::Instruction asInstruction() { none() }
+
+    IR::PointerArithmeticInstruction asPointerArithGuard() { none() }
+
+    IR::Operand asOperand() { none() }
   }
 
-  class SsaVariable instanceof IR::Instruction {
-    SsaVariable() { super.hasMemoryResult() }
+  class SsaInstructionVariable extends SsaVariable, TSsaInstruction {
+    IR::Instruction instr;
 
-    final string toString() { result = super.toString() }
+    SsaInstructionVariable() { this = TSsaInstruction(instr) }
 
-    final Location getLocation() { result = super.getLocation() }
+    final override string toString() { result = instr.toString() }
+
+    final override Location getLocation() { result = instr.getLocation() }
+
+    final override IR::Instruction asInstruction() { result = instr }
   }
 
-  predicate explicitUpdate(SsaVariable v, Expr sourceExpr) { v = sourceExpr }
+  class SsaPointerArithmeticGuard extends SsaVariable, TSsaPointerArithmeticGuard {
+    IR::PointerArithmeticInstruction instr;
 
-  predicate phi(SsaVariable v) { v instanceof IR::PhiInstruction }
+    SsaPointerArithmeticGuard() { this = TSsaPointerArithmeticGuard(instr) }
 
-  SsaVariable getAPhiInput(SsaVariable v) { result = v.(IR::PhiInstruction).getAnInput() }
+    final override string toString() { result = instr.toString() }
 
-  Expr getAUse(SsaVariable v) { result.(IR::LoadInstruction).getSourceValue() = v }
+    final override Location getLocation() { result = instr.getLocation() }
+
+    final override IR::PointerArithmeticInstruction asPointerArithGuard() { result = instr }
+  }
+
+  class SsaOperand extends SsaVariable, TSsaOperand {
+    IR::Operand op;
+
+    SsaOperand() { this = TSsaOperand(op) }
+
+    final override string toString() { result = op.toString() }
+
+    final override Location getLocation() { result = op.getLocation() }
+
+    final override IR::Operand asOperand() { result = op }
+  }
+
+  predicate explicitUpdate(SsaVariable v, Expr sourceExpr) { v.asInstruction() = sourceExpr }
+
+  predicate phi(SsaVariable v) { v.asInstruction() instanceof IR::PhiInstruction }
+
+  SsaVariable getAPhiInput(SsaVariable v) {
+    exists(IR::PhiInstruction instr | v.asInstruction() = instr |
+      result.asInstruction() = instr.getAnInput()
+      or
+      result.asOperand() = instr.getAnInputOperand()
+    )
+  }
+
+  Expr getAUse(SsaVariable v) {
+    result.(IR::LoadInstruction).getSourceValue() = v.asInstruction()
+    or
+    result = valueNumber(v.asPointerArithGuard()).getAnInstruction()
+  }
 
   SemType getSsaVariableType(SsaVariable v) {
-    result = getSemanticType(v.(IR::Instruction).getResultIRType())
+    result = getSemanticType(v.asInstruction().getResultIRType())
   }
 
-  BasicBlock getSsaVariableBasicBlock(SsaVariable v) { result = v.(IR::Instruction).getBlock() }
+  BasicBlock getSsaVariableBasicBlock(SsaVariable v) {
+    result = v.asInstruction().getBlock()
+    or
+    result = v.asOperand().getUse().getBlock()
+  }
 
   private newtype TReadPosition =
     TReadPositionBlock(IR::IRBlock block) or
@@ -169,7 +235,11 @@ module SemanticExprConfig {
 
     final override predicate hasRead(SsaVariable v) {
       exists(IR::Operand operand |
-        operand.getDef() = v and not operand instanceof IR::PhiInputOperand
+        operand.getDef() = v.asInstruction() or
+        operand.getDef() = valueNumber(v.asPointerArithGuard()).getAnInstruction()
+      |
+        not operand instanceof IR::PhiInputOperand and
+        operand.getUse().getBlock() = block
       )
     }
   }
@@ -186,7 +256,9 @@ module SemanticExprConfig {
 
     final override predicate hasRead(SsaVariable v) {
       exists(IR::PhiInputOperand operand |
-        operand.getDef() = v and
+        operand.getDef() = v.asInstruction() or
+        operand.getDef() = valueNumber(v.asPointerArithGuard()).getAnInstruction()
+      |
         operand.getPredecessorBlock() = pred and
         operand.getUse().getBlock() = succ
       )
@@ -205,17 +277,16 @@ module SemanticExprConfig {
     exists(IR::PhiInputOperand operand |
       pos = TReadPositionPhiInputEdge(operand.getPredecessorBlock(), operand.getUse().getBlock())
     |
-      phi = operand.getUse() and input = operand.getDef()
+      phi.asInstruction() = operand.getUse() and
+      (
+        input.asInstruction() = operand.getDef()
+        or
+        input.asOperand() = operand
+      )
     )
   }
 
   class Bound instanceof IRBound::Bound {
-    Bound() {
-      this instanceof IRBound::ZeroBound
-      or
-      this.(IRBound::ValueNumberBound).getValueNumber().getAnInstruction() instanceof SsaVariable
-    }
-
     string toString() { result = super.toString() }
 
     final Location getLocation() { result = super.getLocation() }
@@ -226,23 +297,13 @@ module SemanticExprConfig {
 
     ValueNumberBound() { bound = this }
 
-    override string toString() {
-      result =
-        min(SsaVariable instr |
-          instr = bound.getValueNumber().getAnInstruction()
-        |
-          instr
-          order by
-            instr.(IR::Instruction).getBlock().getDisplayIndex(),
-            instr.(IR::Instruction).getDisplayIndexInBlock()
-        ).toString()
-    }
+    override string toString() { result = bound.toString() }
   }
 
   predicate zeroBound(Bound bound) { bound instanceof IRBound::ZeroBound }
 
   predicate ssaBound(Bound bound, SsaVariable v) {
-    v = bound.(IRBound::ValueNumberBound).getValueNumber().getAnInstruction()
+    v.asInstruction() = bound.(IRBound::ValueNumberBound).getValueNumber().getAnInstruction()
   }
 
   Expr getBoundExpr(Bound bound, int delta) {
@@ -251,22 +312,20 @@ module SemanticExprConfig {
 
   class Guard = IRGuards::IRGuardCondition;
 
-  predicate guard(Guard guard, BasicBlock block) {
-    block = guard.(IRGuards::IRGuardCondition).getBlock()
-  }
+  predicate guard(Guard guard, BasicBlock block) { block = guard.getBlock() }
 
   Expr getGuardAsExpr(Guard guard) { result = guard }
 
   predicate equalityGuard(Guard guard, Expr e1, Expr e2, boolean polarity) {
-    guard.(IRGuards::IRGuardCondition).comparesEq(e1.getAUse(), e2.getAUse(), 0, true, polarity)
+    guard.comparesEq(e1.getAUse(), e2.getAUse(), 0, true, polarity)
   }
 
   predicate guardDirectlyControlsBlock(Guard guard, BasicBlock controlled, boolean branch) {
-    guard.(IRGuards::IRGuardCondition).controls(controlled, branch)
+    guard.controls(controlled, branch)
   }
 
   predicate guardHasBranchEdge(Guard guard, BasicBlock bb1, BasicBlock bb2, boolean branch) {
-    guard.(IRGuards::IRGuardCondition).controlsEdge(bb1, bb2, branch)
+    guard.controlsEdge(bb1, bb2, branch)
   }
 
   Guard comparisonGuard(Expr e) { result = e }
@@ -284,9 +343,13 @@ SemBasicBlock getSemanticBasicBlock(IR::IRBlock block) { result = block }
 
 IR::IRBlock getCppBasicBlock(SemBasicBlock block) { block = result }
 
-SemSsaVariable getSemanticSsaVariable(IR::Instruction instr) { result = instr }
+SemSsaVariable getSemanticSsaVariable(IR::Instruction instr) {
+  result.(SemanticExprConfig::SsaVariable).asInstruction() = instr
+}
 
-IR::Instruction getCppSsaVariableInstruction(SemSsaVariable v) { v = result }
+IR::Instruction getCppSsaVariableInstruction(SemSsaVariable var) {
+  var.(SemanticExprConfig::SsaVariable).asInstruction() = result
+}
 
 SemBound getSemanticBound(IRBound::Bound bound) { result = bound }
 

cpp/ql/lib/experimental/semmle/code/cpp/semantic/SemanticOpcode.qll

@@ -65,10 +65,18 @@ module Opcode {
     override string toString() { result = "Add" }
   }
 
+  class PointerAdd extends Opcode, TPointerAdd {
+    override string toString() { result = "PointerAdd" }
+  }
+
   class Sub extends Opcode, TSub {
     override string toString() { result = "Sub" }
   }
 
+  class PointerSub extends Opcode, TPointerSub {
+    override string toString() { result = "PointerSub" }
+  }
+
   class Mul extends Opcode, TMul {
     override string toString() { result = "Mul" }
   }

cpp/ql/lib/experimental/semmle/code/cpp/semantic/SemanticSSA.qll

@@ -10,7 +10,7 @@ class SemSsaVariable instanceof Specific::SsaVariable {
 
   final Specific::Location getLocation() { result = super.getLocation() }
 
-  final SemLoadExpr getAUse() { result = Specific::getAUse(this) }
+  final SemExpr getAUse() { result = Specific::getAUse(this) }
 
   final SemType getType() { result = Specific::getSsaVariableType(this) }
 

cpp/ql/lib/experimental/semmle/code/cpp/semantic/analysis/ModulusAnalysis.qll

@@ -160,6 +160,7 @@ private predicate phiModulusInit(SemSsaPhiNode phi, SemBound b, int val, int mod
 /**
  * Holds if all inputs to `phi` numbered `1` to `rix` are equal to `b + val` modulo `mod`.
  */
+pragma[nomagic]
 private predicate phiModulusRankStep(SemSsaPhiNode phi, SemBound b, int val, int mod, int rix) {
   rix = 0 and
   phiModulusInit(phi, b, val, mod)
@@ -169,7 +170,7 @@ private predicate phiModulusRankStep(SemSsaPhiNode phi, SemBound b, int val, int
     val = remainder(v1, mod)
   |
     exists(int v2, int m2 |
-      rankedPhiInput(phi, inp, edge, rix) and
+      rankedPhiInput(pragma[only_bind_out](phi), inp, edge, rix) and
       phiModulusRankStep(phi, b, v1, m1, rix - 1) and
       ssaModulus(inp, edge, b, v2, m2) and
       mod = m1.gcd(m2).gcd(v1 - v2)

cpp/ql/lib/experimental/semmle/code/cpp/semantic/analysis/RangeAnalysis.qll

@@ -223,7 +223,9 @@ private SemGuard boundFlowCond(
       else resultIsStrict = testIsTrue.booleanNot()
     ) and
     (
-      if getTrackedTypeForSsaVariable(v) instanceof SemIntegerType
+      if
+        getTrackedTypeForSsaVariable(v) instanceof SemIntegerType or
+        getTrackedTypeForSsaVariable(v) instanceof SemAddressType
       then
         upper = true and strengthen = -1
         or
@@ -342,7 +344,10 @@ private class ConvertOrBoxExpr extends SemUnaryExpr {
  * A cast that can be ignored for the purpose of range analysis.
  */
 private class SafeCastExpr extends ConvertOrBoxExpr {
-  SafeCastExpr() { conversionCannotOverflow(getTrackedType(getOperand()), getTrackedType(this)) }
+  SafeCastExpr() {
+    conversionCannotOverflow(getTrackedType(pragma[only_bind_into](getOperand())),
+      getTrackedType(this))
+  }
 }
 
 /**
@@ -539,12 +544,32 @@ private predicate unequalIntegralSsa(
 ) {
   exists(SemExpr e, int d1, int d2 |
     unequalFlowStepIntegralSsa(v, pos, e, d1, reason) and
-    bounded(e, b, d2, true, _, _, _) and
-    bounded(e, b, d2, false, _, _, _) and
+    boundedUpper(e, b, d1) and
+    boundedLower(e, b, d2) and
     delta = d2 + d1
   )
 }
 
+/**
+ * Holds if `b + delta` is an upper bound for `e`.
+ *
+ * This predicate only exists to prevent a bad standard order in `unequalIntegralSsa`.
+ */
+pragma[nomagic]
+private predicate boundedUpper(SemExpr e, SemBound b, int delta) {
+  bounded(e, b, delta, true, _, _, _)
+}
+
+/**
+ * Holds if `b + delta` is a lower bound for `e`.
+ *
+ * This predicate only exists to prevent a bad standard order in `unequalIntegralSsa`.
+ */
+pragma[nomagic]
+private predicate boundedLower(SemExpr e, SemBound b, int delta) {
+  bounded(e, b, delta, false, _, _, _)
+}
+
 /** Weakens a delta to lie in the range `[-1..1]`. */
 bindingset[delta, upper]
 private int weakenDelta(boolean upper, int delta) {

cpp/ql/lib/experimental/semmle/code/cpp/semantic/analysis/SignAnalysisCommon.qll

@@ -189,9 +189,12 @@ private class BinarySignExpr extends FlowSignExpr {
   BinarySignExpr() { binary = this }
 
   override Sign getSignRestriction() {
-    result =
-      semExprSign(binary.getLeftOperand())
-          .applyBinaryOp(semExprSign(binary.getRightOperand()), binary.getOpcode())
+    exists(SemExpr left, SemExpr right |
+      binaryExprOperands(binary, left, right) and
+      result =
+        semExprSign(pragma[only_bind_out](left))
+            .applyBinaryOp(semExprSign(pragma[only_bind_out](right)), binary.getOpcode())
+    )
     or
     exists(SemDivExpr div | div = binary |
       result = semExprSign(div.getLeftOperand()) and
@@ -201,6 +204,11 @@ private class BinarySignExpr extends FlowSignExpr {
   }
 }
 
+pragma[nomagic]
+private predicate binaryExprOperands(SemBinaryExpr binary, SemExpr left, SemExpr right) {
+  binary.getLeftOperand() = left and binary.getRightOperand() = right
+}
+
 /**
  * A `Convert`, `Box`, or `Unbox` expression.
  */
@@ -221,7 +229,7 @@ private class UnarySignExpr extends FlowSignExpr {
   UnarySignExpr() { unary = this and not this instanceof SemCastExpr }
 
   override Sign getSignRestriction() {
-    result = semExprSign(unary.getOperand()).applyUnaryOp(unary.getOpcode())
+    result = semExprSign(pragma[only_bind_out](unary.getOperand())).applyUnaryOp(unary.getOpcode())
   }
 }
 

cpp/ql/lib/qlpack.yml

@@ -1,7 +1,9 @@
 name: codeql/cpp-all
-version: 0.3.3
+version: 0.4.2-dev
 groups: cpp
 dbscheme: semmlecode.cpp.dbscheme
 extractor: cpp
 library: true
 upgrades: upgrades
+dependencies:
+  codeql/ssa: 0.0.1

cpp/ql/lib/semmle/code/cpp/Class.qll

@@ -404,7 +404,10 @@ class Class extends UserType {
    * compiled for. For this reason, the `is_pod_class` predicate is
    * generated by the extractor.
    */
-  predicate isPOD() { is_pod_class(underlyingElement(this)) }
+  predicate isPod() { is_pod_class(underlyingElement(this)) }
+
+  /** DEPRECATED: Alias for isPod */
+  deprecated predicate isPOD() { this.isPod() }
 
   /**
    * Holds if this class, struct or union is a standard-layout class

cpp/ql/lib/semmle/code/cpp/File.qll

@@ -218,8 +218,6 @@ class Folder extends Container, @folder {
 class File extends Container, @file {
   override string getAbsolutePath() { files(underlyingElement(this), result) }
 
-  override string toString() { result = Container.super.toString() }
-
   override string getAPrimaryQlClass() { result = "File" }
 
   override Location getLocation() {

cpp/ql/lib/semmle/code/cpp/Linkage.qll

@@ -41,6 +41,15 @@ class LinkTarget extends @link_target {
    * translation units which contributed to this link target.
    */
   Class getAClass() { link_parent(unresolveElement(result), this) }
+
+  /**
+   * Gets a global or namespace variable which was compiled into this
+   * link target, or had its declaration included by one of the translation
+   * units which contributed to this link target.
+   */
+  GlobalOrNamespaceVariable getAGlobalOrNamespaceVariable() {
+    link_parent(unresolveElement(result), this)
+  }
 }
 
 /**

cpp/ql/lib/semmle/code/cpp/PODType03.qll

@@ -79,17 +79,17 @@ predicate isAggregateType03(Type t) {
  *   user-defined copy assignment operator and no user-defined destructor.
  *   A POD class is a class that is either a POD-struct or a POD-union.
  */
-predicate isPODClass03(Class c) {
+predicate isPodClass03(Class c) {
   isAggregateClass03(c) and
   not exists(Variable v |
     v.getDeclaringType() = c and
     not v.isStatic()
   |
-    not isPODType03(v.getType())
+    not isPodType03(v.getType())
     or
     exists(ArrayType at |
       at = v.getType() and
-      not isPODType03(at.getBaseType())
+      not isPodType03(at.getBaseType())
     )
     or
     v.getType() instanceof ReferenceType
@@ -104,6 +104,9 @@ predicate isPODClass03(Class c) {
   )
 }
 
+/** DEPRECATED: Alias for isPodClass03 */
+deprecated predicate isPODClass03 = isPodClass03/1;
+
 /**
  * Holds if `t` is a POD type, according to the rules specified in
  * C++03 3.9(10):
@@ -112,14 +115,17 @@ predicate isPODClass03(Class c) {
  *   such types and cv-qualified versions of these types (3.9.3) are
  *   collectively called POD types.
  */
-predicate isPODType03(Type t) {
+predicate isPodType03(Type t) {
   exists(Type ut | ut = t.getUnderlyingType() |
     isScalarType03(ut)
     or
-    isPODClass03(ut)
+    isPodClass03(ut)
     or
-    exists(ArrayType at | at = ut and isPODType03(at.getBaseType()))
+    exists(ArrayType at | at = ut and isPodType03(at.getBaseType()))
     or
-    isPODType03(ut.(SpecifiedType).getUnspecifiedType())
+    isPodType03(ut.(SpecifiedType).getUnspecifiedType())
   )
 }
+
+/** DEPRECATED: Alias for isPodType03 */
+deprecated predicate isPODType03 = isPodType03/1;

cpp/ql/lib/semmle/code/cpp/Specifier.qll

@@ -256,7 +256,7 @@ class AttributeArgument extends Element, @attribute_arg {
 
   /**
    * Gets the text for the value of this argument, if its value is
-   * a constant or token.
+   * a constant or a token.
    */
   string getValueText() {
     if underlyingElement(this) instanceof @attribute_arg_constant_expr

cpp/ql/lib/semmle/code/cpp/Variable.qll

@@ -398,6 +398,8 @@ class LocalVariable extends LocalScopeVariable, @localvariable {
     exists(DeclStmt s | s.getADeclaration() = this and s.getEnclosingFunction() = result)
     or
     exists(ConditionDeclExpr e | e.getVariable() = this and e.getEnclosingFunction() = result)
+    or
+    orphaned_variables(underlyingElement(this), unresolveElement(result))
   }
 }
 
@@ -471,6 +473,9 @@ class GlobalOrNamespaceVariable extends Variable, @globalvariable {
   override Type getType() { globalvariables(underlyingElement(this), unresolveElement(result), _) }
 
   override Element getEnclosingElement() { none() }
+
+  /** Gets a link target which compiled or referenced this global or namespace variable. */
+  LinkTarget getALinkTarget() { this = result.getAGlobalOrNamespaceVariable() }
 }
 
 /**

cpp/ql/lib/semmle/code/cpp/XML.qll

@@ -8,7 +8,7 @@ private class TXmlLocatable =
   @xmldtd or @xmlelement or @xmlattribute or @xmlnamespace or @xmlcomment or @xmlcharacters;
 
 /** An XML element that has a location. */
-class XMLLocatable extends @xmllocatable, TXmlLocatable {
+class XmlLocatable extends @xmllocatable, TXmlLocatable {
   /** Gets the source location for this element. */
   Location getLocation() { xmllocations(this, result) }
 
@@ -32,13 +32,16 @@ class XMLLocatable extends @xmllocatable, TXmlLocatable {
   string toString() { none() } // overridden in subclasses
 }
 
+/** DEPRECATED: Alias for XmlLocatable */
+deprecated class XMLLocatable = XmlLocatable;
+
 /**
- * An `XMLParent` is either an `XMLElement` or an `XMLFile`,
+ * An `XmlParent` is either an `XmlElement` or an `XmlFile`,
  * both of which can contain other elements.
  */
-class XMLParent extends @xmlparent {
-  XMLParent() {
-    // explicitly restrict `this` to be either an `XMLElement` or an `XMLFile`;
+class XmlParent extends @xmlparent {
+  XmlParent() {
+    // explicitly restrict `this` to be either an `XmlElement` or an `XmlFile`;
     // the type `@xmlparent` currently also includes non-XML files
     this instanceof @xmlelement or xmlEncoding(this, _)
   }
@@ -50,28 +53,28 @@ class XMLParent extends @xmlparent {
   string getName() { none() } // overridden in subclasses
 
   /** Gets the file to which this XML parent belongs. */
-  XMLFile getFile() { result = this or xmlElements(this, _, _, _, result) }
+  XmlFile getFile() { result = this or xmlElements(this, _, _, _, result) }
 
   /** Gets the child element at a specified index of this XML parent. */
-  XMLElement getChild(int index) { xmlElements(result, _, this, index, _) }
+  XmlElement getChild(int index) { xmlElements(result, _, this, index, _) }
 
   /** Gets a child element of this XML parent. */
-  XMLElement getAChild() { xmlElements(result, _, this, _, _) }
+  XmlElement getAChild() { xmlElements(result, _, this, _, _) }
 
   /** Gets a child element of this XML parent with the given `name`. */
-  XMLElement getAChild(string name) { xmlElements(result, _, this, _, _) and result.hasName(name) }
+  XmlElement getAChild(string name) { xmlElements(result, _, this, _, _) and result.hasName(name) }
 
   /** Gets a comment that is a child of this XML parent. */
-  XMLComment getAComment() { xmlComments(result, _, this, _) }
+  XmlComment getAComment() { xmlComments(result, _, this, _) }
 
   /** Gets a character sequence that is a child of this XML parent. */
-  XMLCharacters getACharactersSet() { xmlChars(result, _, this, _, _, _) }
+  XmlCharacters getACharactersSet() { xmlChars(result, _, this, _, _, _) }
 
-  /** Gets the depth in the tree. (Overridden in XMLElement.) */
+  /** Gets the depth in the tree. (Overridden in XmlElement.) */
   int getDepth() { result = 0 }
 
   /** Gets the number of child XML elements of this XML parent. */
-  int getNumberOfChildren() { result = count(XMLElement e | xmlElements(e, _, this, _, _)) }
+  int getNumberOfChildren() { result = count(XmlElement e | xmlElements(e, _, this, _, _)) }
 
   /** Gets the number of places in the body of this XML parent where text occurs. */
   int getNumberOfCharacterSets() { result = count(int pos | xmlChars(_, _, this, pos, _, _)) }
@@ -92,9 +95,12 @@ class XMLParent extends @xmlparent {
   string toString() { result = this.getName() }
 }
 
+/** DEPRECATED: Alias for XmlParent */
+deprecated class XMLParent = XmlParent;
+
 /** An XML file. */
-class XMLFile extends XMLParent, File {
-  XMLFile() { xmlEncoding(this, _) }
+class XmlFile extends XmlParent, File {
+  XmlFile() { xmlEncoding(this, _) }
 
   /** Gets a printable representation of this XML file. */
   override string toString() { result = this.getName() }
@@ -120,15 +126,21 @@ class XMLFile extends XMLParent, File {
   string getEncoding() { xmlEncoding(this, result) }
 
   /** Gets the XML file itself. */
-  override XMLFile getFile() { result = this }
+  override XmlFile getFile() { result = this }
 
   /** Gets a top-most element in an XML file. */
-  XMLElement getARootElement() { result = this.getAChild() }
+  XmlElement getARootElement() { result = this.getAChild() }
 
   /** Gets a DTD associated with this XML file. */
-  XMLDTD getADTD() { xmlDTDs(result, _, _, _, this) }
+  XmlDtd getADtd() { xmlDTDs(result, _, _, _, this) }
+
+  /** DEPRECATED: Alias for getADtd */
+  deprecated XmlDtd getADTD() { result = this.getADtd() }
 }
 
+/** DEPRECATED: Alias for XmlFile */
+deprecated class XMLFile = XmlFile;
+
 /**
  * An XML document type definition (DTD).
  *
@@ -140,7 +152,7 @@ class XMLFile extends XMLParent, File {
  * <!ELEMENT lastName (#PCDATA)>
  * ```
  */
-class XMLDTD extends XMLLocatable, @xmldtd {
+class XmlDtd extends XmlLocatable, @xmldtd {
   /** Gets the name of the root element of this DTD. */
   string getRoot() { xmlDTDs(this, result, _, _, _) }
 
@@ -154,7 +166,7 @@ class XMLDTD extends XMLLocatable, @xmldtd {
   predicate isPublic() { not xmlDTDs(this, _, "", _, _) }
 
   /** Gets the parent of this DTD. */
-  XMLParent getParent() { xmlDTDs(this, _, _, _, result) }
+  XmlParent getParent() { xmlDTDs(this, _, _, _, result) }
 
   override string toString() {
     this.isPublic() and
@@ -165,6 +177,9 @@ class XMLDTD extends XMLLocatable, @xmldtd {
   }
 }
 
+/** DEPRECATED: Alias for XmlDtd */
+deprecated class XMLDTD = XmlDtd;
+
 /**
  * An XML element in an XML file.
  *
@@ -176,7 +191,7 @@ class XMLDTD extends XMLLocatable, @xmldtd {
  * </manifest>
  * ```
  */
-class XMLElement extends @xmlelement, XMLParent, XMLLocatable {
+class XmlElement extends @xmlelement, XmlParent, XmlLocatable {
   /** Holds if this XML element has the given `name`. */
   predicate hasName(string name) { name = this.getName() }
 
@@ -184,10 +199,10 @@ class XMLElement extends @xmlelement, XMLParent, XMLLocatable {
   override string getName() { xmlElements(this, result, _, _, _) }
 
   /** Gets the XML file in which this XML element occurs. */
-  override XMLFile getFile() { xmlElements(this, _, _, _, result) }
+  override XmlFile getFile() { xmlElements(this, _, _, _, result) }
 
   /** Gets the parent of this XML element. */
-  XMLParent getParent() { xmlElements(this, _, result, _, _) }
+  XmlParent getParent() { xmlElements(this, _, result, _, _) }
 
   /** Gets the index of this XML element among its parent's children. */
   int getIndex() { xmlElements(this, _, _, result, _) }
@@ -196,7 +211,7 @@ class XMLElement extends @xmlelement, XMLParent, XMLLocatable {
   predicate hasNamespace() { xmlHasNs(this, _, _) }
 
   /** Gets the namespace of this XML element, if any. */
-  XMLNamespace getNamespace() { xmlHasNs(this, result, _) }
+  XmlNamespace getNamespace() { xmlHasNs(this, result, _) }
 
   /** Gets the index of this XML element among its parent's children. */
   int getElementPositionIndex() { xmlElements(this, _, _, result, _) }
@@ -205,10 +220,10 @@ class XMLElement extends @xmlelement, XMLParent, XMLLocatable {
   override int getDepth() { result = this.getParent().getDepth() + 1 }
 
   /** Gets an XML attribute of this XML element. */
-  XMLAttribute getAnAttribute() { result.getElement() = this }
+  XmlAttribute getAnAttribute() { result.getElement() = this }
 
   /** Gets the attribute with the specified `name`, if any. */
-  XMLAttribute getAttribute(string name) { result.getElement() = this and result.getName() = name }
+  XmlAttribute getAttribute(string name) { result.getElement() = this and result.getName() = name }
 
   /** Holds if this XML element has an attribute with the specified `name`. */
   predicate hasAttribute(string name) { exists(this.getAttribute(name)) }
@@ -220,6 +235,9 @@ class XMLElement extends @xmlelement, XMLParent, XMLLocatable {
   override string toString() { result = this.getName() }
 }
 
+/** DEPRECATED: Alias for XmlElement */
+deprecated class XMLElement = XmlElement;
+
 /**
  * An attribute that occurs inside an XML element.
  *
@@ -230,18 +248,18 @@ class XMLElement extends @xmlelement, XMLParent, XMLLocatable {
  * android:versionCode="1"
  * ```
  */
-class XMLAttribute extends @xmlattribute, XMLLocatable {
+class XmlAttribute extends @xmlattribute, XmlLocatable {
   /** Gets the name of this attribute. */
   string getName() { xmlAttrs(this, _, result, _, _, _) }
 
   /** Gets the XML element to which this attribute belongs. */
-  XMLElement getElement() { xmlAttrs(this, result, _, _, _, _) }
+  XmlElement getElement() { xmlAttrs(this, result, _, _, _, _) }
 
   /** Holds if this attribute has a namespace. */
   predicate hasNamespace() { xmlHasNs(this, _, _) }
 
   /** Gets the namespace of this attribute, if any. */
-  XMLNamespace getNamespace() { xmlHasNs(this, result, _) }
+  XmlNamespace getNamespace() { xmlHasNs(this, result, _) }
 
   /** Gets the value of this attribute. */
   string getValue() { xmlAttrs(this, _, _, result, _, _) }
@@ -250,6 +268,9 @@ class XMLAttribute extends @xmlattribute, XMLLocatable {
   override string toString() { result = this.getName() + "=" + this.getValue() }
 }
 
+/** DEPRECATED: Alias for XmlAttribute */
+deprecated class XMLAttribute = XmlAttribute;
+
 /**
  * A namespace used in an XML file.
  *
@@ -259,23 +280,29 @@ class XMLAttribute extends @xmlattribute, XMLLocatable {
  * xmlns:android="http://schemas.android.com/apk/res/android"
  * ```
  */
-class XMLNamespace extends XMLLocatable, @xmlnamespace {
+class XmlNamespace extends XmlLocatable, @xmlnamespace {
   /** Gets the prefix of this namespace. */
   string getPrefix() { xmlNs(this, result, _, _) }
 
   /** Gets the URI of this namespace. */
-  string getURI() { xmlNs(this, _, result, _) }
+  string getUri() { xmlNs(this, _, result, _) }
+
+  /** DEPRECATED: Alias for getUri */
+  deprecated string getURI() { result = this.getUri() }
 
   /** Holds if this namespace has no prefix. */
   predicate isDefault() { this.getPrefix() = "" }
 
   override string toString() {
-    this.isDefault() and result = this.getURI()
+    this.isDefault() and result = this.getUri()
     or
-    not this.isDefault() and result = this.getPrefix() + ":" + this.getURI()
+    not this.isDefault() and result = this.getPrefix() + ":" + this.getUri()
   }
 }
 
+/** DEPRECATED: Alias for XmlNamespace */
+deprecated class XMLNamespace = XmlNamespace;
+
 /**
  * A comment in an XML file.
  *
@@ -285,17 +312,20 @@ class XMLNamespace extends XMLLocatable, @xmlnamespace {
  * <!-- This is a comment. -->
  * ```
  */
-class XMLComment extends @xmlcomment, XMLLocatable {
+class XmlComment extends @xmlcomment, XmlLocatable {
   /** Gets the text content of this XML comment. */
   string getText() { xmlComments(this, result, _, _) }
 
   /** Gets the parent of this XML comment. */
-  XMLParent getParent() { xmlComments(this, _, result, _) }
+  XmlParent getParent() { xmlComments(this, _, result, _) }
 
   /** Gets a printable representation of this XML comment. */
   override string toString() { result = this.getText() }
 }
 
+/** DEPRECATED: Alias for XmlComment */
+deprecated class XMLComment = XmlComment;
+
 /**
  * A sequence of characters that occurs between opening and
  * closing tags of an XML element, excluding other elements.
@@ -306,12 +336,12 @@ class XMLComment extends @xmlcomment, XMLLocatable {
  * <content>This is a sequence of characters.</content>
  * ```
  */
-class XMLCharacters extends @xmlcharacters, XMLLocatable {
+class XmlCharacters extends @xmlcharacters, XmlLocatable {
   /** Gets the content of this character sequence. */
   string getCharacters() { xmlChars(this, result, _, _, _, _) }
 
   /** Gets the parent of this character sequence. */
-  XMLParent getParent() { xmlChars(this, _, result, _, _, _) }
+  XmlParent getParent() { xmlChars(this, _, result, _, _, _) }
 
   /** Holds if this character sequence is CDATA. */
   predicate isCDATA() { xmlChars(this, _, _, _, 1, _) }
@@ -319,3 +349,6 @@ class XMLCharacters extends @xmlcharacters, XMLLocatable {
   /** Gets a printable representation of this XML character sequence. */
   override string toString() { result = this.getCharacters() }
 }
+
+/** DEPRECATED: Alias for XmlCharacters */
+deprecated class XMLCharacters = XmlCharacters;

cpp/ql/lib/semmle/code/cpp/commons/Dependency.qll

@@ -238,7 +238,7 @@ predicate dependsOnTransitive(DependsSource src, Element dest) {
 /**
  * A dependency that targets a TypeDeclarationEntry.
  */
-private predicate dependsOnTDE(Element src, Type t, TypeDeclarationEntry dest) {
+private predicate dependsOnTde(Element src, Type t, TypeDeclarationEntry dest) {
   dependsOnTransitive(src, t) and
   getDeclarationEntries(t, dest)
 }
@@ -247,8 +247,8 @@ private predicate dependsOnTDE(Element src, Type t, TypeDeclarationEntry dest) {
  * A dependency that targets a visible TypeDeclarationEntry.
  */
 pragma[noopt]
-private predicate dependsOnVisibleTDE(Element src, Type t, TypeDeclarationEntry dest) {
-  dependsOnTDE(src, t, dest) and
+private predicate dependsOnVisibleTde(Element src, Type t, TypeDeclarationEntry dest) {
+  dependsOnTde(src, t, dest) and
   exists(File g | g = dest.getFile() |
     exists(File f | f = src.getFile() | f.getAnIncludedFile*() = g)
   )
@@ -260,8 +260,8 @@ private predicate dependsOnVisibleTDE(Element src, Type t, TypeDeclarationEntry
 private predicate dependsOnDeclarationEntry(Element src, DeclarationEntry dest) {
   exists(Type t |
     // dependency from a Type use -> unique visible TDE
-    dependsOnVisibleTDE(src, t, dest) and
-    strictcount(TypeDeclarationEntry alt | dependsOnVisibleTDE(src, t, alt)) = 1
+    dependsOnVisibleTde(src, t, dest) and
+    strictcount(TypeDeclarationEntry alt | dependsOnVisibleTde(src, t, alt)) = 1
   )
   or
   exists(TypedefType mid |

cpp/ql/lib/semmle/code/cpp/commons/NULL.qll

@@ -1,11 +1,14 @@
 import semmle.code.cpp.Macro
 
 /** A macro defining NULL. */
-class NULLMacro extends Macro {
-  NULLMacro() { this.getHead() = "NULL" }
+class NullMacro extends Macro {
+  NullMacro() { this.getHead() = "NULL" }
 }
 
+/** DEPRECATED: Alias for NullMacro */
+deprecated class NULLMacro = NullMacro;
+
 /** A use of the NULL macro. */
 class NULL extends Literal {
-  NULL() { exists(NULLMacro nm | this = nm.getAnInvocation().getAnExpandedElement()) }
+  NULL() { exists(NullMacro nm | this = nm.getAnInvocation().getAnExpandedElement()) }
 }

cpp/ql/lib/semmle/code/cpp/commons/Scanf.qll

@@ -143,6 +143,28 @@ class ScanfFunctionCall extends FunctionCall {
    * (rather than a `char*`).
    */
   predicate isWideCharDefault() { this.getScanfFunction().isWideCharDefault() }
+
+  /**
+   * Gets the output argument at position `n` in the vararg list of this call.
+   *
+   * The range of `n` is from `0` to `this.getNumberOfOutputArguments() - 1`.
+   */
+  Expr getOutputArgument(int n) {
+    result = this.getArgument(this.getTarget().getNumberOfParameters() + n) and
+    n >= 0
+  }
+
+  /**
+   * Gets an output argument given to this call in vararg position.
+   */
+  Expr getAnOutputArgument() { result = this.getOutputArgument(_) }
+
+  /**
+   * Gets the number of output arguments present in this call.
+   */
+  int getNumberOfOutputArguments() {
+    result = this.getNumberOfArguments() - this.getTarget().getNumberOfParameters()
+  }
 }
 
 /**

cpp/ql/lib/semmle/code/cpp/commons/Strcat.qll

@@ -6,7 +6,7 @@ import cpp
  * A function that concatenates the string from its second argument
  * to the string from its first argument, for example `strcat`.
  */
-class StrcatFunction extends Function {
+deprecated class StrcatFunction extends Function {
   StrcatFunction() {
     getName() =
       [

cpp/ql/lib/semmle/code/cpp/controlflow/BasicBlocks.qll

@@ -231,7 +231,7 @@ class BasicBlock extends ControlFlowNodeBase {
     exists(Function f | f.getBlock() = this)
     or
     exists(TryStmt t, BasicBlock tryblock |
-      // a `Handler` preceeds the `CatchBlock`, and is always the beginning
+      // a `Handler` precedes the `CatchBlock`, and is always the beginning
       // of a new `BasicBlock` (see `primitive_basic_block_entry_node`).
       this.(Handler).getTryStmt() = t and
       tryblock.isReachable() and

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll

@@ -163,7 +163,9 @@ abstract class Configuration extends string {
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
    */
-  predicate hasFlowTo(Node sink) { this.hasFlow(_, sink) }
+  predicate hasFlowTo(Node sink) {
+    sink = any(PathNodeSink n | this = n.getConfiguration()).getNodeEx().asNode()
+  }
 
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
@@ -558,13 +560,16 @@ private predicate expectsContentEx(NodeEx n, Content c) {
 pragma[nomagic]
 private predicate notExpectsContent(NodeEx n) { not expectsContentCached(n.asNode(), _) }
 
+pragma[nomagic]
+private predicate hasReadStep(Content c, Configuration config) { read(_, c, _, config) }
+
 pragma[nomagic]
 private predicate store(
   NodeEx node1, TypedContent tc, NodeEx node2, DataFlowType contentType, Configuration config
 ) {
   store(pragma[only_bind_into](node1.asNode()), tc, pragma[only_bind_into](node2.asNode()),
     contentType) and
-  read(_, tc.getContent(), _, config) and
+  hasReadStep(tc.getContent(), config) and
   stepFilter(node1, node2, config)
 }
 
@@ -598,13 +603,9 @@ private predicate hasSinkCallCtx(Configuration config) {
 }
 
 private module Stage1 implements StageSig {
-  class ApApprox = Unit;
-
   class Ap = Unit;
 
-  class ApOption = Unit;
-
-  class Cc = boolean;
+  private class Cc = boolean;
 
   /* Begin: Stage 1 logic. */
   /**
@@ -613,7 +614,7 @@ private module Stage1 implements StageSig {
    * The Boolean `cc` records whether the node is reached through an
    * argument in a call.
    */
-  predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
+  private predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
     sourceNode(node, _, config) and
     if hasSourceCallCtx(config) then cc = true else cc = false
     or
@@ -753,7 +754,7 @@ private module Stage1 implements StageSig {
    * the enclosing callable in order to reach a sink.
    */
   pragma[nomagic]
-  predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
+  private predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
     revFlow0(node, toReturn, config) and
     fwdFlow(node, config)
   }
@@ -837,13 +838,13 @@ private module Stage1 implements StageSig {
    * by `revFlow`.
    */
   pragma[nomagic]
-  predicate revFlowIsReadAndStored(Content c, Configuration conf) {
+  additional predicate revFlowIsReadAndStored(Content c, Configuration conf) {
     revFlowConsCand(c, conf) and
     revFlowStore(c, _, _, conf)
   }
 
   pragma[nomagic]
-  predicate viableReturnPosOutNodeCandFwd1(
+  additional predicate viableReturnPosOutNodeCandFwd1(
     DataFlowCall call, ReturnPosition pos, NodeEx out, Configuration config
   ) {
     fwdFlowReturnPosition(pos, _, config) and
@@ -859,7 +860,7 @@ private module Stage1 implements StageSig {
   }
 
   pragma[nomagic]
-  predicate viableParamArgNodeCandFwd1(
+  additional predicate viableParamArgNodeCandFwd1(
     DataFlowCall call, ParamNodeEx p, ArgNodeEx arg, Configuration config
   ) {
     viableParamArgEx(call, p, arg) and
@@ -906,7 +907,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate revFlowState(FlowState state, Configuration config) {
+  additional predicate revFlowState(FlowState state, Configuration config) {
     exists(NodeEx node |
       sinkNode(node, state, config) and
       revFlow(node, _, pragma[only_bind_into](config)) and
@@ -998,7 +999,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate stats(
+  additional predicate stats(
     boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
   ) {
     fwd = true and
@@ -1259,7 +1260,7 @@ private module MkStage<StageSig PrevStage> {
      * argument.
      */
     pragma[nomagic]
-    predicate fwdFlow(
+    additional predicate fwdFlow(
       NodeEx node, FlowState state, Cc cc, ApOption argAp, Ap ap, Configuration config
     ) {
       fwdFlow0(node, state, cc, argAp, ap, config) and
@@ -1483,7 +1484,7 @@ private module MkStage<StageSig PrevStage> {
      * the access path of the returned value.
      */
     pragma[nomagic]
-    predicate revFlow(
+    additional predicate revFlow(
       NodeEx node, FlowState state, boolean toReturn, ApOption returnAp, Ap ap, Configuration config
     ) {
       revFlow0(node, state, toReturn, returnAp, ap, config) and
@@ -1661,7 +1662,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate revFlow(NodeEx node, FlowState state, Configuration config) {
+    additional predicate revFlow(NodeEx node, FlowState state, Configuration config) {
       revFlow(node, state, _, _, _, config)
     }
 
@@ -1674,11 +1675,13 @@ private module MkStage<StageSig PrevStage> {
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, Configuration config) { revFlow(node, _, _, _, _, config) }
+    additional predicate revFlowAlias(NodeEx node, Configuration config) {
+      revFlow(node, _, _, _, _, config)
+    }
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
+    additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
       revFlow(node, state, ap, config)
     }
 
@@ -1699,7 +1702,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate consCand(TypedContent tc, Ap ap, Configuration config) {
+    additional predicate consCand(TypedContent tc, Ap ap, Configuration config) {
       revConsCand(tc, ap, config) and
       validAp(ap, config)
     }
@@ -1741,7 +1744,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate stats(
+    additional predicate stats(
       boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
     ) {
       fwd = true and
@@ -2926,12 +2929,17 @@ abstract private class PathNodeImpl extends PathNode {
     result = this.getASuccessorImpl()
   }
 
-  final PathNodeImpl getANonHiddenSuccessor() {
-    result = this.getASuccessorImpl().getASuccessorIfHidden*() and
-    not this.isHidden() and
+  pragma[nomagic]
+  private PathNodeImpl getANonHiddenSuccessor0() {
+    result = this.getASuccessorIfHidden*() and
     not result.isHidden()
   }
 
+  final PathNodeImpl getANonHiddenSuccessor() {
+    result = this.getASuccessorImpl().getANonHiddenSuccessor0() and
+    not this.isHidden()
+  }
+
   abstract NodeEx getNodeEx();
 
   predicate isHidden() {
@@ -3061,7 +3069,7 @@ private class PathNodeMid extends PathNodeImpl, TPathNodeMid {
       else cc instanceof CallContextAny
     ) and
     sc instanceof SummaryCtxNone and
-    ap instanceof AccessPathNil
+    ap = TAccessPathNil(node.getDataFlowType())
   }
 
   predicate isAtSink() {

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl2.qll

@@ -163,7 +163,9 @@ abstract class Configuration extends string {
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
    */
-  predicate hasFlowTo(Node sink) { this.hasFlow(_, sink) }
+  predicate hasFlowTo(Node sink) {
+    sink = any(PathNodeSink n | this = n.getConfiguration()).getNodeEx().asNode()
+  }
 
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
@@ -558,13 +560,16 @@ private predicate expectsContentEx(NodeEx n, Content c) {
 pragma[nomagic]
 private predicate notExpectsContent(NodeEx n) { not expectsContentCached(n.asNode(), _) }
 
+pragma[nomagic]
+private predicate hasReadStep(Content c, Configuration config) { read(_, c, _, config) }
+
 pragma[nomagic]
 private predicate store(
   NodeEx node1, TypedContent tc, NodeEx node2, DataFlowType contentType, Configuration config
 ) {
   store(pragma[only_bind_into](node1.asNode()), tc, pragma[only_bind_into](node2.asNode()),
     contentType) and
-  read(_, tc.getContent(), _, config) and
+  hasReadStep(tc.getContent(), config) and
   stepFilter(node1, node2, config)
 }
 
@@ -598,13 +603,9 @@ private predicate hasSinkCallCtx(Configuration config) {
 }
 
 private module Stage1 implements StageSig {
-  class ApApprox = Unit;
-
   class Ap = Unit;
 
-  class ApOption = Unit;
-
-  class Cc = boolean;
+  private class Cc = boolean;
 
   /* Begin: Stage 1 logic. */
   /**
@@ -613,7 +614,7 @@ private module Stage1 implements StageSig {
    * The Boolean `cc` records whether the node is reached through an
    * argument in a call.
    */
-  predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
+  private predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
     sourceNode(node, _, config) and
     if hasSourceCallCtx(config) then cc = true else cc = false
     or
@@ -753,7 +754,7 @@ private module Stage1 implements StageSig {
    * the enclosing callable in order to reach a sink.
    */
   pragma[nomagic]
-  predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
+  private predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
     revFlow0(node, toReturn, config) and
     fwdFlow(node, config)
   }
@@ -837,13 +838,13 @@ private module Stage1 implements StageSig {
    * by `revFlow`.
    */
   pragma[nomagic]
-  predicate revFlowIsReadAndStored(Content c, Configuration conf) {
+  additional predicate revFlowIsReadAndStored(Content c, Configuration conf) {
     revFlowConsCand(c, conf) and
     revFlowStore(c, _, _, conf)
   }
 
   pragma[nomagic]
-  predicate viableReturnPosOutNodeCandFwd1(
+  additional predicate viableReturnPosOutNodeCandFwd1(
     DataFlowCall call, ReturnPosition pos, NodeEx out, Configuration config
   ) {
     fwdFlowReturnPosition(pos, _, config) and
@@ -859,7 +860,7 @@ private module Stage1 implements StageSig {
   }
 
   pragma[nomagic]
-  predicate viableParamArgNodeCandFwd1(
+  additional predicate viableParamArgNodeCandFwd1(
     DataFlowCall call, ParamNodeEx p, ArgNodeEx arg, Configuration config
   ) {
     viableParamArgEx(call, p, arg) and
@@ -906,7 +907,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate revFlowState(FlowState state, Configuration config) {
+  additional predicate revFlowState(FlowState state, Configuration config) {
     exists(NodeEx node |
       sinkNode(node, state, config) and
       revFlow(node, _, pragma[only_bind_into](config)) and
@@ -998,7 +999,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate stats(
+  additional predicate stats(
     boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
   ) {
     fwd = true and
@@ -1259,7 +1260,7 @@ private module MkStage<StageSig PrevStage> {
      * argument.
      */
     pragma[nomagic]
-    predicate fwdFlow(
+    additional predicate fwdFlow(
       NodeEx node, FlowState state, Cc cc, ApOption argAp, Ap ap, Configuration config
     ) {
       fwdFlow0(node, state, cc, argAp, ap, config) and
@@ -1483,7 +1484,7 @@ private module MkStage<StageSig PrevStage> {
      * the access path of the returned value.
      */
     pragma[nomagic]
-    predicate revFlow(
+    additional predicate revFlow(
       NodeEx node, FlowState state, boolean toReturn, ApOption returnAp, Ap ap, Configuration config
     ) {
       revFlow0(node, state, toReturn, returnAp, ap, config) and
@@ -1661,7 +1662,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate revFlow(NodeEx node, FlowState state, Configuration config) {
+    additional predicate revFlow(NodeEx node, FlowState state, Configuration config) {
       revFlow(node, state, _, _, _, config)
     }
 
@@ -1674,11 +1675,13 @@ private module MkStage<StageSig PrevStage> {
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, Configuration config) { revFlow(node, _, _, _, _, config) }
+    additional predicate revFlowAlias(NodeEx node, Configuration config) {
+      revFlow(node, _, _, _, _, config)
+    }
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
+    additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
       revFlow(node, state, ap, config)
     }
 
@@ -1699,7 +1702,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate consCand(TypedContent tc, Ap ap, Configuration config) {
+    additional predicate consCand(TypedContent tc, Ap ap, Configuration config) {
       revConsCand(tc, ap, config) and
       validAp(ap, config)
     }
@@ -1741,7 +1744,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate stats(
+    additional predicate stats(
       boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
     ) {
       fwd = true and
@@ -2926,12 +2929,17 @@ abstract private class PathNodeImpl extends PathNode {
     result = this.getASuccessorImpl()
   }
 
-  final PathNodeImpl getANonHiddenSuccessor() {
-    result = this.getASuccessorImpl().getASuccessorIfHidden*() and
-    not this.isHidden() and
+  pragma[nomagic]
+  private PathNodeImpl getANonHiddenSuccessor0() {
+    result = this.getASuccessorIfHidden*() and
     not result.isHidden()
   }
 
+  final PathNodeImpl getANonHiddenSuccessor() {
+    result = this.getASuccessorImpl().getANonHiddenSuccessor0() and
+    not this.isHidden()
+  }
+
   abstract NodeEx getNodeEx();
 
   predicate isHidden() {
@@ -3061,7 +3069,7 @@ private class PathNodeMid extends PathNodeImpl, TPathNodeMid {
       else cc instanceof CallContextAny
     ) and
     sc instanceof SummaryCtxNone and
-    ap instanceof AccessPathNil
+    ap = TAccessPathNil(node.getDataFlowType())
   }
 
   predicate isAtSink() {

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl3.qll

@@ -163,7 +163,9 @@ abstract class Configuration extends string {
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
    */
-  predicate hasFlowTo(Node sink) { this.hasFlow(_, sink) }
+  predicate hasFlowTo(Node sink) {
+    sink = any(PathNodeSink n | this = n.getConfiguration()).getNodeEx().asNode()
+  }
 
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
@@ -558,13 +560,16 @@ private predicate expectsContentEx(NodeEx n, Content c) {
 pragma[nomagic]
 private predicate notExpectsContent(NodeEx n) { not expectsContentCached(n.asNode(), _) }
 
+pragma[nomagic]
+private predicate hasReadStep(Content c, Configuration config) { read(_, c, _, config) }
+
 pragma[nomagic]
 private predicate store(
   NodeEx node1, TypedContent tc, NodeEx node2, DataFlowType contentType, Configuration config
 ) {
   store(pragma[only_bind_into](node1.asNode()), tc, pragma[only_bind_into](node2.asNode()),
     contentType) and
-  read(_, tc.getContent(), _, config) and
+  hasReadStep(tc.getContent(), config) and
   stepFilter(node1, node2, config)
 }
 
@@ -598,13 +603,9 @@ private predicate hasSinkCallCtx(Configuration config) {
 }
 
 private module Stage1 implements StageSig {
-  class ApApprox = Unit;
-
   class Ap = Unit;
 
-  class ApOption = Unit;
-
-  class Cc = boolean;
+  private class Cc = boolean;
 
   /* Begin: Stage 1 logic. */
   /**
@@ -613,7 +614,7 @@ private module Stage1 implements StageSig {
    * The Boolean `cc` records whether the node is reached through an
    * argument in a call.
    */
-  predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
+  private predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
     sourceNode(node, _, config) and
     if hasSourceCallCtx(config) then cc = true else cc = false
     or
@@ -753,7 +754,7 @@ private module Stage1 implements StageSig {
    * the enclosing callable in order to reach a sink.
    */
   pragma[nomagic]
-  predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
+  private predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
     revFlow0(node, toReturn, config) and
     fwdFlow(node, config)
   }
@@ -837,13 +838,13 @@ private module Stage1 implements StageSig {
    * by `revFlow`.
    */
   pragma[nomagic]
-  predicate revFlowIsReadAndStored(Content c, Configuration conf) {
+  additional predicate revFlowIsReadAndStored(Content c, Configuration conf) {
     revFlowConsCand(c, conf) and
     revFlowStore(c, _, _, conf)
   }
 
   pragma[nomagic]
-  predicate viableReturnPosOutNodeCandFwd1(
+  additional predicate viableReturnPosOutNodeCandFwd1(
     DataFlowCall call, ReturnPosition pos, NodeEx out, Configuration config
   ) {
     fwdFlowReturnPosition(pos, _, config) and
@@ -859,7 +860,7 @@ private module Stage1 implements StageSig {
   }
 
   pragma[nomagic]
-  predicate viableParamArgNodeCandFwd1(
+  additional predicate viableParamArgNodeCandFwd1(
     DataFlowCall call, ParamNodeEx p, ArgNodeEx arg, Configuration config
   ) {
     viableParamArgEx(call, p, arg) and
@@ -906,7 +907,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate revFlowState(FlowState state, Configuration config) {
+  additional predicate revFlowState(FlowState state, Configuration config) {
     exists(NodeEx node |
       sinkNode(node, state, config) and
       revFlow(node, _, pragma[only_bind_into](config)) and
@@ -998,7 +999,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate stats(
+  additional predicate stats(
     boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
   ) {
     fwd = true and
@@ -1259,7 +1260,7 @@ private module MkStage<StageSig PrevStage> {
      * argument.
      */
     pragma[nomagic]
-    predicate fwdFlow(
+    additional predicate fwdFlow(
       NodeEx node, FlowState state, Cc cc, ApOption argAp, Ap ap, Configuration config
     ) {
       fwdFlow0(node, state, cc, argAp, ap, config) and
@@ -1483,7 +1484,7 @@ private module MkStage<StageSig PrevStage> {
      * the access path of the returned value.
      */
     pragma[nomagic]
-    predicate revFlow(
+    additional predicate revFlow(
       NodeEx node, FlowState state, boolean toReturn, ApOption returnAp, Ap ap, Configuration config
     ) {
       revFlow0(node, state, toReturn, returnAp, ap, config) and
@@ -1661,7 +1662,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate revFlow(NodeEx node, FlowState state, Configuration config) {
+    additional predicate revFlow(NodeEx node, FlowState state, Configuration config) {
       revFlow(node, state, _, _, _, config)
     }
 
@@ -1674,11 +1675,13 @@ private module MkStage<StageSig PrevStage> {
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, Configuration config) { revFlow(node, _, _, _, _, config) }
+    additional predicate revFlowAlias(NodeEx node, Configuration config) {
+      revFlow(node, _, _, _, _, config)
+    }
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
+    additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
       revFlow(node, state, ap, config)
     }
 
@@ -1699,7 +1702,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate consCand(TypedContent tc, Ap ap, Configuration config) {
+    additional predicate consCand(TypedContent tc, Ap ap, Configuration config) {
       revConsCand(tc, ap, config) and
       validAp(ap, config)
     }
@@ -1741,7 +1744,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate stats(
+    additional predicate stats(
       boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
     ) {
       fwd = true and
@@ -2926,12 +2929,17 @@ abstract private class PathNodeImpl extends PathNode {
     result = this.getASuccessorImpl()
   }
 
-  final PathNodeImpl getANonHiddenSuccessor() {
-    result = this.getASuccessorImpl().getASuccessorIfHidden*() and
-    not this.isHidden() and
+  pragma[nomagic]
+  private PathNodeImpl getANonHiddenSuccessor0() {
+    result = this.getASuccessorIfHidden*() and
     not result.isHidden()
   }
 
+  final PathNodeImpl getANonHiddenSuccessor() {
+    result = this.getASuccessorImpl().getANonHiddenSuccessor0() and
+    not this.isHidden()
+  }
+
   abstract NodeEx getNodeEx();
 
   predicate isHidden() {
@@ -3061,7 +3069,7 @@ private class PathNodeMid extends PathNodeImpl, TPathNodeMid {
       else cc instanceof CallContextAny
     ) and
     sc instanceof SummaryCtxNone and
-    ap instanceof AccessPathNil
+    ap = TAccessPathNil(node.getDataFlowType())
   }
 
   predicate isAtSink() {

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl4.qll

@@ -163,7 +163,9 @@ abstract class Configuration extends string {
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
    */
-  predicate hasFlowTo(Node sink) { this.hasFlow(_, sink) }
+  predicate hasFlowTo(Node sink) {
+    sink = any(PathNodeSink n | this = n.getConfiguration()).getNodeEx().asNode()
+  }
 
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
@@ -558,13 +560,16 @@ private predicate expectsContentEx(NodeEx n, Content c) {
 pragma[nomagic]
 private predicate notExpectsContent(NodeEx n) { not expectsContentCached(n.asNode(), _) }
 
+pragma[nomagic]
+private predicate hasReadStep(Content c, Configuration config) { read(_, c, _, config) }
+
 pragma[nomagic]
 private predicate store(
   NodeEx node1, TypedContent tc, NodeEx node2, DataFlowType contentType, Configuration config
 ) {
   store(pragma[only_bind_into](node1.asNode()), tc, pragma[only_bind_into](node2.asNode()),
     contentType) and
-  read(_, tc.getContent(), _, config) and
+  hasReadStep(tc.getContent(), config) and
   stepFilter(node1, node2, config)
 }
 
@@ -598,13 +603,9 @@ private predicate hasSinkCallCtx(Configuration config) {
 }
 
 private module Stage1 implements StageSig {
-  class ApApprox = Unit;
-
   class Ap = Unit;
 
-  class ApOption = Unit;
-
-  class Cc = boolean;
+  private class Cc = boolean;
 
   /* Begin: Stage 1 logic. */
   /**
@@ -613,7 +614,7 @@ private module Stage1 implements StageSig {
    * The Boolean `cc` records whether the node is reached through an
    * argument in a call.
    */
-  predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
+  private predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
     sourceNode(node, _, config) and
     if hasSourceCallCtx(config) then cc = true else cc = false
     or
@@ -753,7 +754,7 @@ private module Stage1 implements StageSig {
    * the enclosing callable in order to reach a sink.
    */
   pragma[nomagic]
-  predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
+  private predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
     revFlow0(node, toReturn, config) and
     fwdFlow(node, config)
   }
@@ -837,13 +838,13 @@ private module Stage1 implements StageSig {
    * by `revFlow`.
    */
   pragma[nomagic]
-  predicate revFlowIsReadAndStored(Content c, Configuration conf) {
+  additional predicate revFlowIsReadAndStored(Content c, Configuration conf) {
     revFlowConsCand(c, conf) and
     revFlowStore(c, _, _, conf)
   }
 
   pragma[nomagic]
-  predicate viableReturnPosOutNodeCandFwd1(
+  additional predicate viableReturnPosOutNodeCandFwd1(
     DataFlowCall call, ReturnPosition pos, NodeEx out, Configuration config
   ) {
     fwdFlowReturnPosition(pos, _, config) and
@@ -859,7 +860,7 @@ private module Stage1 implements StageSig {
   }
 
   pragma[nomagic]
-  predicate viableParamArgNodeCandFwd1(
+  additional predicate viableParamArgNodeCandFwd1(
     DataFlowCall call, ParamNodeEx p, ArgNodeEx arg, Configuration config
   ) {
     viableParamArgEx(call, p, arg) and
@@ -906,7 +907,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate revFlowState(FlowState state, Configuration config) {
+  additional predicate revFlowState(FlowState state, Configuration config) {
     exists(NodeEx node |
       sinkNode(node, state, config) and
       revFlow(node, _, pragma[only_bind_into](config)) and
@@ -998,7 +999,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate stats(
+  additional predicate stats(
     boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
   ) {
     fwd = true and
@@ -1259,7 +1260,7 @@ private module MkStage<StageSig PrevStage> {
      * argument.
      */
     pragma[nomagic]
-    predicate fwdFlow(
+    additional predicate fwdFlow(
       NodeEx node, FlowState state, Cc cc, ApOption argAp, Ap ap, Configuration config
     ) {
       fwdFlow0(node, state, cc, argAp, ap, config) and
@@ -1483,7 +1484,7 @@ private module MkStage<StageSig PrevStage> {
      * the access path of the returned value.
      */
     pragma[nomagic]
-    predicate revFlow(
+    additional predicate revFlow(
       NodeEx node, FlowState state, boolean toReturn, ApOption returnAp, Ap ap, Configuration config
     ) {
       revFlow0(node, state, toReturn, returnAp, ap, config) and
@@ -1661,7 +1662,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate revFlow(NodeEx node, FlowState state, Configuration config) {
+    additional predicate revFlow(NodeEx node, FlowState state, Configuration config) {
       revFlow(node, state, _, _, _, config)
     }
 
@@ -1674,11 +1675,13 @@ private module MkStage<StageSig PrevStage> {
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, Configuration config) { revFlow(node, _, _, _, _, config) }
+    additional predicate revFlowAlias(NodeEx node, Configuration config) {
+      revFlow(node, _, _, _, _, config)
+    }
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
+    additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
       revFlow(node, state, ap, config)
     }
 
@@ -1699,7 +1702,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate consCand(TypedContent tc, Ap ap, Configuration config) {
+    additional predicate consCand(TypedContent tc, Ap ap, Configuration config) {
       revConsCand(tc, ap, config) and
       validAp(ap, config)
     }
@@ -1741,7 +1744,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate stats(
+    additional predicate stats(
       boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
     ) {
       fwd = true and
@@ -2926,12 +2929,17 @@ abstract private class PathNodeImpl extends PathNode {
     result = this.getASuccessorImpl()
   }
 
-  final PathNodeImpl getANonHiddenSuccessor() {
-    result = this.getASuccessorImpl().getASuccessorIfHidden*() and
-    not this.isHidden() and
+  pragma[nomagic]
+  private PathNodeImpl getANonHiddenSuccessor0() {
+    result = this.getASuccessorIfHidden*() and
     not result.isHidden()
   }
 
+  final PathNodeImpl getANonHiddenSuccessor() {
+    result = this.getASuccessorImpl().getANonHiddenSuccessor0() and
+    not this.isHidden()
+  }
+
   abstract NodeEx getNodeEx();
 
   predicate isHidden() {
@@ -3061,7 +3069,7 @@ private class PathNodeMid extends PathNodeImpl, TPathNodeMid {
       else cc instanceof CallContextAny
     ) and
     sc instanceof SummaryCtxNone and
-    ap instanceof AccessPathNil
+    ap = TAccessPathNil(node.getDataFlowType())
   }
 
   predicate isAtSink() {

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImplCommon.qll

@@ -709,7 +709,8 @@ private module Cached {
      */
     pragma[nomagic]
     private DataFlowCallable viableImplInCallContextExt(DataFlowCall call, DataFlowCall ctx) {
-      result = viableImplInCallContext(call, ctx)
+      result = viableImplInCallContext(call, ctx) and
+      result = viableCallable(call)
       or
       result = viableCallableLambda(call, TDataFlowCallSome(ctx))
       or

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImplConsistency.qll

@@ -32,6 +32,19 @@ module Consistency {
 
     /** Holds if `n` should be excluded from the consistency test `reverseRead`. */
     predicate reverseReadExclude(Node n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `postHasUniquePre`. */
+    predicate postHasUniquePreExclude(PostUpdateNode n) { none() }
+
+    /** Holds if `n` should be excluded from the consistency test `uniquePostUpdate`. */
+    predicate uniquePostUpdateExclude(Node n) { none() }
+
+    /** Holds if `(call, ctx)` should be excluded from the consistency test `viableImplInCallContextTooLargeExclude`. */
+    predicate viableImplInCallContextTooLargeExclude(
+      DataFlowCall call, DataFlowCall ctx, DataFlowCallable callable
+    ) {
+      none()
+    }
   }
 
   private class RelevantNode extends Node {
@@ -166,6 +179,7 @@ module Consistency {
   }
 
   query predicate postHasUniquePre(PostUpdateNode n, string msg) {
+    not any(ConsistencyConfiguration conf).postHasUniquePreExclude(n) and
     exists(int c |
       c = count(n.getPreUpdateNode()) and
       c != 1 and
@@ -174,6 +188,7 @@ module Consistency {
   }
 
   query predicate uniquePostUpdate(Node n, string msg) {
+    not any(ConsistencyConfiguration conf).uniquePostUpdateExclude(n) and
     1 < strictcount(PostUpdateNode post | post.getPreUpdateNode() = n) and
     msg = "Node has multiple PostUpdateNodes."
   }
@@ -209,4 +224,12 @@ module Consistency {
     not any(ConsistencyConfiguration c).postWithInFlowExclude(n) and
     msg = "PostUpdateNode should not be the target of local flow."
   }
+
+  query predicate viableImplInCallContextTooLarge(
+    DataFlowCall call, DataFlowCall ctx, DataFlowCallable callable
+  ) {
+    callable = viableImplInCallContext(call, ctx) and
+    not callable = viableCallable(call) and
+    not any(ConsistencyConfiguration c).viableImplInCallContextTooLargeExclude(call, ctx, callable)
+  }
 }

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImplLocal.qll

@@ -163,7 +163,9 @@ abstract class Configuration extends string {
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
    */
-  predicate hasFlowTo(Node sink) { this.hasFlow(_, sink) }
+  predicate hasFlowTo(Node sink) {
+    sink = any(PathNodeSink n | this = n.getConfiguration()).getNodeEx().asNode()
+  }
 
   /**
    * Holds if data may flow from some source to `sink` for this configuration.
@@ -558,13 +560,16 @@ private predicate expectsContentEx(NodeEx n, Content c) {
 pragma[nomagic]
 private predicate notExpectsContent(NodeEx n) { not expectsContentCached(n.asNode(), _) }
 
+pragma[nomagic]
+private predicate hasReadStep(Content c, Configuration config) { read(_, c, _, config) }
+
 pragma[nomagic]
 private predicate store(
   NodeEx node1, TypedContent tc, NodeEx node2, DataFlowType contentType, Configuration config
 ) {
   store(pragma[only_bind_into](node1.asNode()), tc, pragma[only_bind_into](node2.asNode()),
     contentType) and
-  read(_, tc.getContent(), _, config) and
+  hasReadStep(tc.getContent(), config) and
   stepFilter(node1, node2, config)
 }
 
@@ -598,13 +603,9 @@ private predicate hasSinkCallCtx(Configuration config) {
 }
 
 private module Stage1 implements StageSig {
-  class ApApprox = Unit;
-
   class Ap = Unit;
 
-  class ApOption = Unit;
-
-  class Cc = boolean;
+  private class Cc = boolean;
 
   /* Begin: Stage 1 logic. */
   /**
@@ -613,7 +614,7 @@ private module Stage1 implements StageSig {
    * The Boolean `cc` records whether the node is reached through an
    * argument in a call.
    */
-  predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
+  private predicate fwdFlow(NodeEx node, Cc cc, Configuration config) {
     sourceNode(node, _, config) and
     if hasSourceCallCtx(config) then cc = true else cc = false
     or
@@ -753,7 +754,7 @@ private module Stage1 implements StageSig {
    * the enclosing callable in order to reach a sink.
    */
   pragma[nomagic]
-  predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
+  private predicate revFlow(NodeEx node, boolean toReturn, Configuration config) {
     revFlow0(node, toReturn, config) and
     fwdFlow(node, config)
   }
@@ -837,13 +838,13 @@ private module Stage1 implements StageSig {
    * by `revFlow`.
    */
   pragma[nomagic]
-  predicate revFlowIsReadAndStored(Content c, Configuration conf) {
+  additional predicate revFlowIsReadAndStored(Content c, Configuration conf) {
     revFlowConsCand(c, conf) and
     revFlowStore(c, _, _, conf)
   }
 
   pragma[nomagic]
-  predicate viableReturnPosOutNodeCandFwd1(
+  additional predicate viableReturnPosOutNodeCandFwd1(
     DataFlowCall call, ReturnPosition pos, NodeEx out, Configuration config
   ) {
     fwdFlowReturnPosition(pos, _, config) and
@@ -859,7 +860,7 @@ private module Stage1 implements StageSig {
   }
 
   pragma[nomagic]
-  predicate viableParamArgNodeCandFwd1(
+  additional predicate viableParamArgNodeCandFwd1(
     DataFlowCall call, ParamNodeEx p, ArgNodeEx arg, Configuration config
   ) {
     viableParamArgEx(call, p, arg) and
@@ -906,7 +907,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate revFlowState(FlowState state, Configuration config) {
+  additional predicate revFlowState(FlowState state, Configuration config) {
     exists(NodeEx node |
       sinkNode(node, state, config) and
       revFlow(node, _, pragma[only_bind_into](config)) and
@@ -998,7 +999,7 @@ private module Stage1 implements StageSig {
     )
   }
 
-  predicate stats(
+  additional predicate stats(
     boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
   ) {
     fwd = true and
@@ -1259,7 +1260,7 @@ private module MkStage<StageSig PrevStage> {
      * argument.
      */
     pragma[nomagic]
-    predicate fwdFlow(
+    additional predicate fwdFlow(
       NodeEx node, FlowState state, Cc cc, ApOption argAp, Ap ap, Configuration config
     ) {
       fwdFlow0(node, state, cc, argAp, ap, config) and
@@ -1483,7 +1484,7 @@ private module MkStage<StageSig PrevStage> {
      * the access path of the returned value.
      */
     pragma[nomagic]
-    predicate revFlow(
+    additional predicate revFlow(
       NodeEx node, FlowState state, boolean toReturn, ApOption returnAp, Ap ap, Configuration config
     ) {
       revFlow0(node, state, toReturn, returnAp, ap, config) and
@@ -1661,7 +1662,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate revFlow(NodeEx node, FlowState state, Configuration config) {
+    additional predicate revFlow(NodeEx node, FlowState state, Configuration config) {
       revFlow(node, state, _, _, _, config)
     }
 
@@ -1674,11 +1675,13 @@ private module MkStage<StageSig PrevStage> {
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, Configuration config) { revFlow(node, _, _, _, _, config) }
+    additional predicate revFlowAlias(NodeEx node, Configuration config) {
+      revFlow(node, _, _, _, _, config)
+    }
 
     // use an alias as a workaround for bad functionality-induced joins
     pragma[nomagic]
-    predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
+    additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap, Configuration config) {
       revFlow(node, state, ap, config)
     }
 
@@ -1699,7 +1702,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate consCand(TypedContent tc, Ap ap, Configuration config) {
+    additional predicate consCand(TypedContent tc, Ap ap, Configuration config) {
       revConsCand(tc, ap, config) and
       validAp(ap, config)
     }
@@ -1741,7 +1744,7 @@ private module MkStage<StageSig PrevStage> {
       )
     }
 
-    predicate stats(
+    additional predicate stats(
       boolean fwd, int nodes, int fields, int conscand, int states, int tuples, Configuration config
     ) {
       fwd = true and
@@ -2926,12 +2929,17 @@ abstract private class PathNodeImpl extends PathNode {
     result = this.getASuccessorImpl()
   }
 
-  final PathNodeImpl getANonHiddenSuccessor() {
-    result = this.getASuccessorImpl().getASuccessorIfHidden*() and
-    not this.isHidden() and
+  pragma[nomagic]
+  private PathNodeImpl getANonHiddenSuccessor0() {
+    result = this.getASuccessorIfHidden*() and
     not result.isHidden()
   }
 
+  final PathNodeImpl getANonHiddenSuccessor() {
+    result = this.getASuccessorImpl().getANonHiddenSuccessor0() and
+    not this.isHidden()
+  }
+
   abstract NodeEx getNodeEx();
 
   predicate isHidden() {
@@ -3061,7 +3069,7 @@ private class PathNodeMid extends PathNodeImpl, TPathNodeMid {
       else cc instanceof CallContextAny
     ) and
     sc instanceof SummaryCtxNone and
-    ap instanceof AccessPathNil
+    ap = TAccessPathNil(node.getDataFlowType())
   }
 
   predicate isAtSink() {

cpp/ql/lib/semmle/code/cpp/dataflow/internal/FlowVar.qll

@@ -474,7 +474,7 @@ module FlowVar_internal {
   }
 
   /** Type-specialized version of `getEnclosingElement`. */
-  private ControlFlowNode getCFNParent(ControlFlowNode node) { result = node.getEnclosingElement() }
+  private ControlFlowNode getCfnParent(ControlFlowNode node) { result = node.getEnclosingElement() }
 
   /**
    * A for-loop or while-loop whose condition is always true upon entry but not
@@ -526,7 +526,7 @@ module FlowVar_internal {
     }
 
     private predicate bbInLoopCondition(BasicBlock bb) {
-      getCFNParent*(bb.getANode()) = this.(Loop).getCondition()
+      getCfnParent*(bb.getANode()) = this.(Loop).getCondition()
     }
 
     private predicate bbInLoop(BasicBlock bb) {

cpp/ql/lib/semmle/code/cpp/dataflow/internal/tainttracking1/TaintTrackingImpl.qll

@@ -172,7 +172,12 @@ abstract class Configuration extends DataFlow::Configuration {
   }
 
   override predicate allowImplicitRead(DataFlow::Node node, DataFlow::ContentSet c) {
-    (this.isSink(node) or this.isAdditionalTaintStep(node, _)) and
+    (
+      this.isSink(node) or
+      this.isSink(node, _) or
+      this.isAdditionalTaintStep(node, _) or
+      this.isAdditionalTaintStep(node, _, _, _)
+    ) and
     defaultImplicitTaintRead(node, c)
   }