Merge pull request #16715 from github/release-prep/2.17.5

Release preparation for version 2.17.5

.bazelrc

@@ -10,11 +10,19 @@ common --override_module=semmle_code=%workspace%/misc/bazel/semmle_code_stub
 
 build --repo_env=CC=clang --repo_env=CXX=clang++
 
-build:linux --cxxopt=-std=c++20
-build:macos --cxxopt=-std=c++20 --cpu=darwin_x86_64
-build:windows --cxxopt=/std:c++20 --cxxopt=/Zc:preprocessor
+# we use transitions that break builds of `...`, so for `test` to work with that we need the following
+test --build_tests_only
+
+# this requires developer mode, but is required to have pack installer functioning
+startup --windows_enable_symlinks
+common --enable_runfiles
+
+# with the above, we can avoid building python zips which is the default on windows as that's expensive
+build --nobuild_python_zip
 
 common --registry=file:///%workspace%/misc/bazel/registry
 common --registry=https://bcr.bazel.build
 
+common --@rules_dotnet//dotnet/settings:strict_deps=false
+
 try-import %workspace%/local.bazelrc

.bazelrc.internal

@@ -2,3 +2,9 @@
 
 common --registry=file:///%workspace%/ql/misc/bazel/registry
 common --registry=https://bcr.bazel.build
+
+# See bazelbuild/rules_dotnet#413: strict_deps in C# also appliy to 3rd-party deps, and when we pull
+# in (for example) the xunit package, there's no code in this at all, it just depends transitively on
+# its implementation packages without providing any code itself.
+# We either can depend on internal implementation details, or turn of strict deps.
+common --@rules_dotnet//dotnet/settings:strict_deps=false

.bazelversion

@@ -1 +1 @@
-7.1.0
+7.1.2

.gitattributes

@@ -50,26 +50,40 @@
 *.dll -text
 *.pdb -text
 
-java/ql/test/stubs/**/*.java linguist-generated=true
-java/ql/test/experimental/stubs/**/*.java linguist-generated=true
+/java/ql/test/stubs/**/*.java linguist-generated=true
+/java/ql/test/experimental/stubs/**/*.java linguist-generated=true
+/java/kotlin-extractor/deps/*.jar filter=lfs diff=lfs merge=lfs -text
 
 # Force git not to modify line endings for go or html files under the go/ql directory
-go/ql/**/*.go -text
-go/ql/**/*.html -text
+/go/ql/**/*.go -text
+/go/ql/**/*.html -text
 # Force git not to modify line endings for go dbschemes
-go/*.dbscheme -text
+/go/*.dbscheme -text
 # Preserve unusual line ending from codeql-go merge
-go/extractor/opencsv/CSVReader.java -text
+/go/extractor/opencsv/CSVReader.java -text
 
 # For some languages, upgrade script testing references really old dbscheme
 # files from legacy upgrades that have CRLF line endings. Since upgrade
 # resolution relies on object hashes, we must suppress line ending conversion
 # for those testing dbscheme files.
-*/ql/lib/upgrades/initial/*.dbscheme -text
+/*/ql/lib/upgrades/initial/*.dbscheme -text
 
 # Auto-generated modeling for Python
-python/ql/lib/semmle/python/frameworks/data/internal/subclass-capture/*.yml linguist-generated=true
+/python/ql/lib/semmle/python/frameworks/data/internal/subclass-capture/*.yml linguist-generated=true
 
 # auto-generated bazel lock file
-ruby/extractor/cargo-bazel-lock.json linguist-generated=true
-ruby/extractor/cargo-bazel-lock.json -merge
+/ruby/extractor/cargo-bazel-lock.json linguist-generated=true
+/ruby/extractor/cargo-bazel-lock.json -merge
+
+# auto-generated files for the C# build
+/csharp/paket.lock linguist-generated=true
+# needs eol=crlf, as `paket` touches this file and saves it as crlf
+/csharp/.paket/Paket.Restore.targets linguist-generated=true eol=crlf
+/csharp/paket.main.bzl linguist-generated=true
+/csharp/paket.main_extension.bzl linguist-generated=true
+
+# ripunzip tool
+/misc/ripunzip/ripunzip-* filter=lfs diff=lfs merge=lfs -text
+
+# swift prebuilt resources
+/swift/third_party/resource-dir/*.zip filter=lfs diff=lfs merge=lfs -text

.github/workflows/build-ripunzip.yml

@@ -0,0 +1,74 @@
+name: Build runzip
+
+on:
+  workflow_dispatch:
+    inputs:
+      ripunzip-version:
+        description: "what reference to checktout from google/runzip"
+        required: false
+        default: v1.2.1
+      openssl-version:
+        description: "what reference to checkout from openssl/openssl for Linux"
+        required: false
+        default: openssl-3.3.0
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-20.04, macos-12, windows-2019]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          repository: google/ripunzip
+          ref: ${{ inputs.ripunzip-version }}
+      # we need to avoid ripunzip dynamically linking into libssl
+      # see https://github.com/sfackler/rust-openssl/issues/183
+      - if: runner.os == 'Linux'
+        name: checkout openssl
+        uses: actions/checkout@v4
+        with:
+          repository: openssl/openssl
+          path: openssl
+          ref: ${{ inputs.openssl-version }}
+      - if: runner.os == 'Linux'
+        name: build and install openssl with fPIC
+        shell: bash
+        working-directory: openssl
+        run: |
+          ./config -fPIC --prefix=$HOME/.local --openssldir=$HOME/.local/ssl
+          make -j $(nproc)
+          make install_sw -j $(nproc)
+      - if: runner.os == 'Linux'
+        name: build (linux)
+        shell: bash
+        run: |
+          env OPENSSL_LIB_DIR=$HOME/.local/lib64 OPENSSL_INCLUDE_DIR=$HOME/.local/include OPENSSL_STATIC=yes cargo build --release
+          mv target/release/ripunzip ripunzip-linux
+      - if: runner.os == 'Windows'
+        name: build (windows)
+        shell: bash
+        run: |
+          cargo build --release
+          mv target/release/ripunzip ripunzip-windows
+      - name: build (macOS)
+        if: runner.os == 'macOS'
+        shell: bash
+        run: |
+          rustup target install x86_64-apple-darwin
+          rustup target install aarch64-apple-darwin
+          cargo build --target x86_64-apple-darwin --release
+          cargo build --target aarch64-apple-darwin --release
+          lipo -create -output ripunzip-macos \
+            -arch x86_64 target/x86_64-apple-darwin/release/ripunzip \
+            -arch arm64 target/aarch64-apple-darwin/release/ripunzip
+      - uses: actions/upload-artifact@v4
+        with:
+          name: ripunzip-${{ runner.os }}
+          path: ripunzip-*
+      - name: Check built binary
+        shell: bash
+        run: |
+          ./ripunzip-* --version

.github/workflows/buildifier.yml

@@ -24,5 +24,5 @@ jobs:
           extra_args: >
             buildifier --all-files 2>&1 ||
             (
-              echo -e "In order to format all bazel files, please run:\n  bazel run //:buildifier"; exit 1
+              echo -e "In order to format all bazel files, please run:\n  bazel run //misc/bazel:buildifier"; exit 1
             )

.github/workflows/codeql-analysis.yml

@@ -56,7 +56,9 @@ jobs:
     #    uses a compiled language
 
     - run: |
-       dotnet build csharp
+       cd csharp
+       dotnet tool restore
+       dotnet build .
 
     - name: Perform CodeQL Analysis
       uses: github/codeql-action/analyze@main

.github/workflows/csharp-qltest.yml

@@ -65,7 +65,7 @@ jobs:
           key: csharp-qltest-${{ matrix.slice }}
       - name: Run QL tests
         run: |
-          codeql test run --threads=0 --ram 50000 --slice ${{ matrix.slice }} --search-path extractor-pack --check-databases --check-undefined-labels --check-repeated-labels --check-redefined-labels --consistency-queries ql/consistency-queries ql/test --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}"
+          codeql test run --threads=0 --ram 50000 --slice ${{ matrix.slice }} --search-path "${{ github.workspace }}" --check-databases --check-undefined-labels --check-repeated-labels --check-redefined-labels --consistency-queries ql/consistency-queries ql/test --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}"
         env:
           GITHUB_TOKEN: ${{ github.token }}
   unit-tests:
@@ -81,10 +81,11 @@ jobs:
           dotnet-version: 8.0.101
       - name: Extractor unit tests
         run: |
+          dotnet tool restore
           dotnet test -p:RuntimeFrameworkVersion=8.0.1 extractor/Semmle.Util.Tests
           dotnet test -p:RuntimeFrameworkVersion=8.0.1 extractor/Semmle.Extraction.Tests
           dotnet test -p:RuntimeFrameworkVersion=8.0.1 autobuilder/Semmle.Autobuild.CSharp.Tests
-          dotnet test -p:RuntimeFrameworkVersion=8.0.1 "${{ github.workspace }}/cpp/autobuilder/Semmle.Autobuild.Cpp.Tests"
+          dotnet test -p:RuntimeFrameworkVersion=8.0.1 autobuilder/Semmle.Autobuild.Cpp.Tests
         shell: bash
   stubgentest:
     runs-on: ubuntu-latest
@@ -100,6 +101,6 @@ jobs:
           # Update existing stubs in the repo with the freshly generated ones
           mv "$STUBS_PATH/output/stubs/_frameworks" ql/test/resources/stubs/
           git status
-          codeql test run --threads=0 --search-path extractor-pack --check-databases --check-undefined-labels --check-repeated-labels --check-redefined-labels --consistency-queries ql/consistency-queries -- ql/test/library-tests/dataflow/flowsources/aspremote
+          codeql test run --threads=0 --search-path "${{ github.workspace }}" --check-databases --check-undefined-labels --check-repeated-labels --check-redefined-labels --consistency-queries ql/consistency-queries -- ql/test/library-tests/dataflow/flowsources/aspremote
         env:
           GITHUB_TOKEN: ${{ github.token }}

.github/workflows/go-tests-other-os.yml

@@ -7,8 +7,9 @@ on:
       - .github/workflows/go-tests-other-os.yml
       - .github/actions/**
       - codeql-workspace.yml
-env:
-  GO_VERSION: '~1.22.0'
+      - MODULE.bazel
+      - .bazelrc
+      - misc/bazel/**
 
 permissions:
   contents: read
@@ -18,72 +19,17 @@ jobs:
     name: Test MacOS
     runs-on: macos-latest
     steps:
-      - name: Set up Go ${{ env.GO_VERSION }}
-        uses: actions/setup-go@v5
-        with:
-          go-version: ${{ env.GO_VERSION }}
-          cache: false
-        id: go
-
       - name: Check out code
         uses: actions/checkout@v4
-
-      - name: Set up CodeQL CLI
-        uses: ./.github/actions/fetch-codeql
-
-      - name: Enable problem matchers in repository
-        shell: bash
-        run: 'find .github/problem-matchers -name \*.json -exec echo "::add-matcher::{}" \;'
-
-      - name: Build
-        run: |
-          cd go
-          make
-
-      - name: Cache compilation cache
-        id: query-cache
-        uses: ./.github/actions/cache-query-compilation
-        with:
-          key: go-qltest
-      - name: Test
-        run: |
-          cd go
-          make test cache="${{ steps.query-cache.outputs.cache-dir }}"
+      - name: Run tests
+        uses: ./go/actions/test
 
   test-win:
     if: github.repository_owner == 'github'
     name: Test Windows
     runs-on: windows-latest-xl
     steps:
-      - name: Set up Go ${{ env.GO_VERSION }}
-        uses: actions/setup-go@v5
-        with:
-          go-version: ${{ env.GO_VERSION }}
-          cache: false
-        id: go
-
       - name: Check out code
         uses: actions/checkout@v4
-
-      - name: Set up CodeQL CLI
-        uses: ./.github/actions/fetch-codeql
-
-      - name: Enable problem matchers in repository
-        shell: bash
-        run: 'find .github/problem-matchers -name \*.json -exec echo "::add-matcher::{}" \;'
-
-      - name: Build
-        run: |
-          cd go
-          make
-
-      - name: Cache compilation cache
-        id: query-cache
-        uses: ./.github/actions/cache-query-compilation
-        with:
-          key: go-qltest
-
-      - name: Test
-        run: |
-          cd go
-          make test cache="${{ steps.query-cache.outputs.cache-dir }}"
+      - name: Run tests
+        uses: ./go/actions/test

.github/workflows/go-tests.yml

@@ -15,9 +15,9 @@ on:
       - .github/workflows/go-tests.yml
       - .github/actions/**
       - codeql-workspace.yml
-
-env:
-  GO_VERSION: '~1.22.0'
+      - MODULE.bazel
+      - .bazelrc
+      - misc/bazel/**
 
 permissions:
   contents: read
@@ -28,51 +28,9 @@ jobs:
     name: Test Linux (Ubuntu)
     runs-on: ubuntu-latest-xl
     steps:
-      - name: Set up Go ${{ env.GO_VERSION }}
-        uses: actions/setup-go@v5
-        with:
-          go-version: ${{ env.GO_VERSION }}
-          cache: false
-        id: go
-
       - name: Check out code
         uses: actions/checkout@v4
-
-      - name: Set up CodeQL CLI
-        uses: ./.github/actions/fetch-codeql
-
-      - name: Enable problem matchers in repository
-        shell: bash
-        run: 'find .github/problem-matchers -name \*.json -exec echo "::add-matcher::{}" \;'
-
-      - name: Build
-        run: |
-          cd go
-          make
-
-      - name: Check that all Go code is autoformatted
-        run: |
-          cd go
-          make check-formatting
-
-      - name: Compile qhelp files to markdown
-        run: |
-          cd go
-          env QHELP_OUT_DIR=qhelp-out make qhelp-to-markdown
-
-      - name: Upload qhelp markdown
-        uses: actions/upload-artifact@v3
+      - name: Run tests
+        uses: ./go/actions/test
         with:
-          name: qhelp-markdown
-          path: go/qhelp-out/**/*.md
-
-      - name: Cache compilation cache
-        id: query-cache
-        uses: ./.github/actions/cache-query-compilation
-        with:
-          key: go-qltest
-
-      - name: Test
-        run: |
-          cd go
-          make test cache="${{ steps.query-cache.outputs.cache-dir }}"
+          run-code-checks: true

.github/workflows/kotlin-build.yml

@@ -0,0 +1,28 @@
+name: "Kotlin Build"
+
+on:
+  pull_request:
+    paths:
+      - "java/kotlin-extractor/**"
+      - "misc/bazel/**"
+      - "misc/codegen/**"
+      - "*.bazel*"
+      - .github/workflows/kotlin-build.yml
+    branches:
+      - main
+      - rc/*
+      - codeql-cli-*
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: |
+          bazel query //java/kotlin-extractor/...
+          # only build the default version as a quick check that we can build from `codeql`
+          # the full official build will be checked by QLucie
+          bazel build //java/kotlin-extractor

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

@@ -49,20 +49,20 @@ jobs:
           key: ${{ runner.os }}-${{ steps.os_version.outputs.version }}-rust-cargo-${{ hashFiles('ql/**/Cargo.lock') }}
       - name: Release build
         if: steps.cache-extractor.outputs.cache-hit != 'true'
-        run: cd ql; ./scripts/create-extractor-pack.sh       
+        run: cd ql; ./scripts/create-extractor-pack.sh
         env:
-          GH_TOKEN: ${{ github.token }}   
+          GH_TOKEN: ${{ github.token }}
       - name: Cache compilation cache
         id: query-cache
         uses: ./.github/actions/cache-query-compilation
-        with: 
+        with:
           key: run-ql-for-ql
       - name: Make database and analyze
         run: |
           ./ql/target/release/buramu | tee deprecated.blame # Add a blame file for the extractor to parse.
-          ${CODEQL} database create -l=ql --search-path ql/extractor-pack ${DB}
+          ${CODEQL} database create -l=ql ${DB} --search-path "${{ github.workspace }}"
           ${CODEQL} database analyze -j0 --format=sarif-latest --output=ql-for-ql.sarif ${DB} ql/ql/src/codeql-suites/ql-code-scanning.qls  --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}"
-        env: 
+        env:
           CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
           DB: ${{ runner.temp }}/DB
           LGTM_INDEX_FILTERS: |

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

@@ -53,8 +53,8 @@ jobs:
       - name: Create database
         run: |
           "${CODEQL}" database create \
-            --search-path "ql/extractor-pack" \
-            --threads 4 \
+          --search-path "${{ github.workspace }}"
+          --threads 4 \
             --language ql --source-root "${{ github.workspace }}/repo" \
             "${{ runner.temp }}/database"
         env:

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

@@ -49,15 +49,15 @@ jobs:
       - name: Cache compilation cache
         id: query-cache
         uses: ./.github/actions/cache-query-compilation
-        with: 
+        with:
           key: ql-for-ql-tests
       - name: Run QL tests
         run: |
-          "${CODEQL}" test run --check-databases --check-unused-labels --check-repeated-labels --check-redefined-labels --check-use-before-definition --search-path "${{ github.workspace }}/ql/extractor-pack" --consistency-queries ql/ql/consistency-queries --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}" ql/ql/test
+          "${CODEQL}" test run --check-databases --check-unused-labels --check-repeated-labels --check-redefined-labels --check-use-before-definition --search-path "${{ github.workspace }}" --consistency-queries ql/ql/consistency-queries --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}" ql/ql/test
         env:
           CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
 
-  other-os: 
+  other-os:
     strategy:
       matrix:
         os: [macos-latest, windows-latest]
@@ -65,7 +65,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
-      - name: Install GNU tar 
+      - name: Install GNU tar
         if: runner.os == 'macOS'
         run: |
           brew install gnu-tar
@@ -100,7 +100,7 @@ jobs:
       - name: Run a single QL tests - Unix
         if: runner.os != 'Windows'
         run: |
-          "${CODEQL}" test run --check-databases --search-path "${{ github.workspace }}/ql/extractor-pack" ql/ql/test/queries/style/DeadCode/DeadCode.qlref
+          "${CODEQL}" test run --check-databases --search-path "${{ github.workspace }}" ql/ql/test/queries/style/DeadCode/DeadCode.qlref
         env:
           CODEQL: ${{ steps.find-codeql.outputs.codeql-path }}
       - name: Run a single QL tests - Windows
@@ -108,5 +108,4 @@ jobs:
         shell: pwsh
         run: |
           $Env:PATH += ";$(dirname ${{ steps.find-codeql.outputs.codeql-path }})"
-          codeql test run --check-databases --search-path "${{ github.workspace }}/ql/extractor-pack" ql/ql/test/queries/style/DeadCode/DeadCode.qlref
-      
+          codeql test run --check-databases --search-path "${{ github.workspace }}" ql/ql/test/queries/style/DeadCode/DeadCode.qlref

.github/workflows/ruby-dataset-measure.yml

@@ -44,7 +44,7 @@ jobs:
       - name: Create database
         run: |
           codeql database create \
-            --search-path "${{ github.workspace }}/ruby/extractor-pack" \
+            --search-path "${{ github.workspace }}" \
             --threads 4 \
             --language ruby --source-root "${{ github.workspace }}/repo" \
             "${{ runner.temp }}/database"

.github/workflows/ruby-qltest.yml

@@ -64,10 +64,10 @@ jobs:
       - name: Cache compilation cache
         id: query-cache
         uses: ./.github/actions/cache-query-compilation
-        with: 
+        with:
           key: ruby-qltest
       - name: Run QL tests
         run: |
-          codeql test run --threads=0 --ram 50000 --search-path "${{ github.workspace }}/ruby/extractor-pack" --check-databases --check-undefined-labels --check-unused-labels --check-repeated-labels --check-redefined-labels --check-use-before-definition --consistency-queries ql/consistency-queries ql/test --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}"
+          codeql test run --threads=0 --ram 50000 --search-path "${{ github.workspace }}" --check-databases --check-undefined-labels --check-unused-labels --check-repeated-labels --check-redefined-labels --check-use-before-definition --consistency-queries ql/consistency-queries ql/test --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}"
         env:
           GITHUB_TOKEN: ${{ github.token }}

.github/workflows/swift.yml

@@ -68,21 +68,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./swift/actions/run-ql-tests
-  integration-tests-linux:
-    if: github.repository_owner == 'github'
-    needs: build-and-test-linux
-    runs-on: ubuntu-latest-xl
-    steps:
-      - uses: actions/checkout@v4
-      - uses: ./swift/actions/run-integration-tests
-  integration-tests-macos:
-    if: ${{ github.repository_owner == 'github' && github.event_name == 'pull_request' }}
-    needs: build-and-test-macos
-    runs-on: macos-12-xl
-    timeout-minutes: 60
-    steps:
-      - uses: actions/checkout@v4
-      - uses: ./swift/actions/run-integration-tests
   clang-format:
     if : ${{ github.event_name == 'pull_request' }}
     runs-on: ubuntu-latest

.github/workflows/zipmerge-test.yml

@@ -0,0 +1,23 @@
+name: "Test zipmerge code"
+
+on:
+  pull_request:
+    paths:
+      - "misc/bazel/internal/zipmerge/**"
+      - "MODULE.bazel"
+      - ".bazelrc*"
+    branches:
+      - main
+      - "rc/*"
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - run: |
+          bazel test //misc/bazel/internal/zipmerge:test --test_output=all

.gitignore

@@ -62,3 +62,6 @@ node_modules/
 
 # Temporary folders for working with generated models
 .model-temp
+
+# bazel-built in-tree extractor packs
+/*/extractor-pack

.lfsconfig

@@ -0,0 +1,7 @@
+[lfs]
+# codeql is publicly forked by many users, and we don't want any LFS file polluting their working
+# copies. We therefore exclude everything by default.
+# For files required by bazel builds, use rules in `misc/bazel/lfs.bzl` to download them on demand.
+# we go for `fetchinclude` to something not exsiting rather than `fetchexclude = *` because the
+# former is easier to override (with `git -c` or a local git config) to fetch something specific
+fetchinclude = /nothing

.pre-commit-config.yaml

@@ -26,9 +26,17 @@ repos:
         name: Format bazel files
         files: \.(bazel|bzl)
         language: system
-        entry: bazel run //:buildifier
+        entry: bazel run //misc/bazel:buildifier
         pass_filenames: false
 
+#      DISABLED: can be enabled by copying this config and installing `pre-commit` with `--config` on the copy
+#      - id: go-gen
+#        name: Check checked in generated files in go
+#        files: ^go/.*
+#        language: system
+#        entry: bazel run //go:gen
+#        pass_filenames: false
+
       - id: codeql-format
         name: Fix QL file formatting
         files: \.qll?$

BUILD.bazel

@@ -1,9 +1 @@
-load("@buildifier_prebuilt//:rules.bzl", "buildifier")
-
-buildifier(
-    name = "buildifier",
-    exclude_patterns = [
-        "./.git/*",
-    ],
-    lint_mode = "fix",
-)
+exports_files(["LICENSE"])

CODEOWNERS

@@ -1,6 +1,7 @@
 /cpp/ @github/codeql-c-analysis
-/cpp/autobuilder/ @github/codeql-c-extractor
 /csharp/ @github/codeql-csharp
+/csharp/autobuilder/Semmle.Autobuild.Cpp @github/codeql-c-extractor
+/csharp/autobuilder/Semmle.Autobuild.Cpp.Tests @github/codeql-c-extractor
 /go/ @github/codeql-go
 /java/ @github/codeql-java
 /javascript/ @github/codeql-javascript

CONTRIBUTING.md

@@ -4,6 +4,8 @@ We welcome contributions to our CodeQL libraries and queries. Got an idea for a
 
 There is lots of useful documentation to help you write queries, ranging from information about query file structure to tutorials for specific target languages. For more information on the documentation available, see [CodeQL queries](https://codeql.github.com/docs/writing-codeql-queries/codeql-queries) on [codeql.github.com](https://codeql.github.com).
 
+Note that the CodeQL for Visual Studio Code documentation has been migrated to https://docs.github.com/en/code-security/codeql-for-vs-code/, but you can still contribute to it via a different repository. For more information, see [Contributing to GitHub Docs documentation](https://docs.github.com/en/contributing)."
+
 ## Change notes
 
 Any nontrivial user-visible change to a query pack or library pack should have a change note. For details on how to add a change note for your change, see [this guide](docs/change-notes.md).
@@ -43,7 +45,7 @@ If you have an idea for a query that you would like to share with other CodeQL u
 
 3. **Formatting**
 
-    - The queries and libraries must be autoformatted, for example using the "Format Document" command in [CodeQL for Visual Studio Code](https://codeql.github.com/docs/codeql-for-visual-studio-code/about-codeql-for-visual-studio-code).
+    - The queries and libraries must be autoformatted, for example using the "Format Document" command in [CodeQL for Visual Studio Code](https://docs.github.com/en/code-security/codeql-for-vs-code/).
 
     If you prefer, you can either:
     1. install the [pre-commit framework](https://pre-commit.com/) and install the configured hooks on this repo via `pre-commit install`, or

MODULE.bazel

@@ -13,7 +13,8 @@ local_path_override(
 
 # see https://registry.bazel.build/ for a list of available packages
 
-bazel_dep(name = "platforms", version = "0.0.8")
+bazel_dep(name = "platforms", version = "0.0.9")
+bazel_dep(name = "rules_go", version = "0.47.0")
 bazel_dep(name = "rules_pkg", version = "0.10.1")
 bazel_dep(name = "rules_nodejs", version = "6.0.3")
 bazel_dep(name = "rules_python", version = "0.31.0")
@@ -21,9 +22,22 @@ bazel_dep(name = "bazel_skylib", version = "1.5.0")
 bazel_dep(name = "abseil-cpp", version = "20240116.0", repo_name = "absl")
 bazel_dep(name = "nlohmann_json", version = "3.11.3", repo_name = "json")
 bazel_dep(name = "fmt", version = "10.0.0")
+bazel_dep(name = "rules_kotlin", version = "1.9.4-codeql.1")
+bazel_dep(name = "gazelle", version = "0.36.0")
+bazel_dep(name = "rules_dotnet", version = "0.15.1")
+bazel_dep(name = "googletest", version = "1.14.0.bcr.1")
 
 bazel_dep(name = "buildifier_prebuilt", version = "6.4.0", dev_dependency = True)
 
+dotnet = use_extension("@rules_dotnet//dotnet:extensions.bzl", "dotnet")
+dotnet.toolchain(dotnet_version = "8.0.101")
+use_repo(dotnet, "dotnet_toolchains")
+
+register_toolchains("@dotnet_toolchains//:all")
+
+csharp_main_extension = use_extension("//csharp:paket.main_extension.bzl", "main_extension")
+use_repo(csharp_main_extension, "paket.main")
+
 pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
 pip.parse(
     hub_name = "codegen_deps",
@@ -52,6 +66,84 @@ node.toolchain(
 )
 use_repo(node, "nodejs", "nodejs_toolchains")
 
+kotlin_extractor_deps = use_extension("//java/kotlin-extractor:deps.bzl", "kotlin_extractor_deps")
+
+# following list can be kept in sync by running `bazel mod tidy` in `codeql`
+use_repo(
+    kotlin_extractor_deps,
+    "codeql_kotlin_defaults",
+    "codeql_kotlin_embeddable",
+    "kotlin-compiler-1.5.0",
+    "kotlin-compiler-1.5.10",
+    "kotlin-compiler-1.5.20",
+    "kotlin-compiler-1.5.30",
+    "kotlin-compiler-1.6.0",
+    "kotlin-compiler-1.6.20",
+    "kotlin-compiler-1.7.0",
+    "kotlin-compiler-1.7.20",
+    "kotlin-compiler-1.8.0",
+    "kotlin-compiler-1.9.0-Beta",
+    "kotlin-compiler-1.9.20-Beta",
+    "kotlin-compiler-2.0.0-RC1",
+    "kotlin-compiler-embeddable-1.5.0",
+    "kotlin-compiler-embeddable-1.5.10",
+    "kotlin-compiler-embeddable-1.5.20",
+    "kotlin-compiler-embeddable-1.5.30",
+    "kotlin-compiler-embeddable-1.6.0",
+    "kotlin-compiler-embeddable-1.6.20",
+    "kotlin-compiler-embeddable-1.7.0",
+    "kotlin-compiler-embeddable-1.7.20",
+    "kotlin-compiler-embeddable-1.8.0",
+    "kotlin-compiler-embeddable-1.9.0-Beta",
+    "kotlin-compiler-embeddable-1.9.20-Beta",
+    "kotlin-compiler-embeddable-2.0.0-RC1",
+    "kotlin-stdlib-1.5.0",
+    "kotlin-stdlib-1.5.10",
+    "kotlin-stdlib-1.5.20",
+    "kotlin-stdlib-1.5.30",
+    "kotlin-stdlib-1.6.0",
+    "kotlin-stdlib-1.6.20",
+    "kotlin-stdlib-1.7.0",
+    "kotlin-stdlib-1.7.20",
+    "kotlin-stdlib-1.8.0",
+    "kotlin-stdlib-1.9.0-Beta",
+    "kotlin-stdlib-1.9.20-Beta",
+    "kotlin-stdlib-2.0.0-RC1",
+)
+
+go_sdk = use_extension("@rules_go//go:extensions.bzl", "go_sdk")
+go_sdk.download(version = "1.22.2")
+
+lfs_files = use_repo_rule("//misc/bazel:lfs.bzl", "lfs_files")
+
+lfs_files(
+    name = "ripunzip-linux",
+    srcs = ["//misc/ripunzip:ripunzip-linux"],
+    executable = True,
+)
+
+lfs_files(
+    name = "ripunzip-windows",
+    srcs = ["//misc/ripunzip:ripunzip-windows.exe"],
+    executable = True,
+)
+
+lfs_files(
+    name = "ripunzip-macos",
+    srcs = ["//misc/ripunzip:ripunzip-macos"],
+    executable = True,
+)
+
+lfs_files(
+    name = "swift-resource-dir-linux",
+    srcs = ["//swift/third_party/resource-dir:resource-dir-linux.zip"],
+)
+
+lfs_files(
+    name = "swift-resource-dir-macos",
+    srcs = ["//swift/third_party/resource-dir:resource-dir-macos.zip"],
+)
+
 register_toolchains(
     "@nodejs_toolchains//:all",
 )

README.md

@@ -4,7 +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 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/).
+There is extensive documentation about the [CodeQL language](https://codeql.github.com/docs/), writing CodeQL using the [CodeQL extension for Visual Studio Code](https://docs.github.com/en/code-security/codeql-for-vs-code/) and using the [CodeQL CLI](https://docs.github.com/en/code-security/codeql-cli).
 
 ## Contributing
 

codeql-workspace.yml

@@ -6,19 +6,16 @@ provide:
   - "*/ql/consistency-queries/qlpack.yml"
   - "*/ql/automodel/src/qlpack.yml"
   - "*/ql/automodel/test/qlpack.yml"
+  - "*/extractor-pack/codeql-extractor.yml"
   - "python/extractor/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"
   - "csharp/ql/campaigns/Solorigate/lib/qlpack.yml"
   - "csharp/ql/campaigns/Solorigate/src/qlpack.yml"
   - "csharp/ql/campaigns/Solorigate/test/qlpack.yml"
   - "misc/legacy-support/*/qlpack.yml"
   - "misc/suite-helpers/qlpack.yml"
-  - "ruby/extractor-pack/codeql-extractor.yml"
-  - "swift/extractor-pack/codeql-extractor.yml"
-  - "ql/extractor-pack/codeql-extractor.yml"
   - ".github/codeql/extensions/**/codeql-pack.yml"
 
 versionPolicies:

config/dbscheme-fragments.json

@@ -28,6 +28,7 @@
     "/*- Yaml dbscheme -*/",
     "/*- Blame dbscheme -*/",
     "/*- JSON dbscheme -*/",
-    "/*- Python dbscheme -*/"
+    "/*- Python dbscheme -*/",
+    "/*- Empty location -*/"
   ]
 }

config/identical-files.json

@@ -364,5 +364,9 @@
   "Python model summaries test extension": [
     "python/ql/test/library-tests/dataflow/model-summaries/InlineTaintTest.ext.yml",
     "python/ql/test/library-tests/dataflow/model-summaries/NormalDataflowTest.ext.yml"
+  ],
+  "shared tree-sitter extractor cargo.toml": [
+    "shared/tree-sitter-extractor/Cargo.toml",
+    "ruby/extractor/codeql-extractor-fake-crate/Cargo.toml"
   ]
 }

cpp/autobuilder/.gitignore

@@ -1,13 +0,0 @@
-obj/
-TestResults/
-*.manifest
-*.pdb
-*.suo
-*.mdb
-*.vsmdi
-csharp.log
-**/bin/Debug
-**/bin/Release
-*.tlog
-.vs
-*.user

cpp/autobuilder/README.md

@@ -0,0 +1 @@
+The Windows autobuilder that used to live in this directory moved to `csharp/autobuilder/Semmle.Autobuild.Cpp`.

cpp/autobuilder/Semmle.Autobuild.Cpp.Tests/Semmle.Autobuild.Cpp.Tests.csproj

@@ -1,26 +0,0 @@
-<Project Sdk="Microsoft.NET.Sdk">
-
-  <PropertyGroup>
-    <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
-    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
-    <RuntimeIdentifiers>win-x64;linux-x64;osx-x64</RuntimeIdentifiers>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
-
-  <ItemGroup>
-    <PackageReference Include="System.IO.FileSystem" Version="4.3.0" />
-    <PackageReference Include="System.IO.FileSystem.Primitives" Version="4.3.0" />
-    <PackageReference Include="xunit" Version="2.6.2" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.4">
-      <PrivateAssets>all</PrivateAssets>
-      <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
-    </PackageReference>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <ProjectReference Include="..\Semmle.Autobuild.Cpp\Semmle.Autobuild.Cpp.csproj" />
-    <ProjectReference Include="..\..\..\csharp\autobuilder\Semmle.Autobuild.Shared\Semmle.Autobuild.Shared.csproj" />
-  </ItemGroup>
-</Project>

cpp/autobuilder/Semmle.Autobuild.Cpp/Properties/AssemblyInfo.cs

@@ -1,32 +0,0 @@
-using System.Reflection;
-using System.Runtime.InteropServices;
-
-// General Information about an assembly is controlled through the following
-// set of attributes. Change these attribute values to modify the information
-// associated with an assembly.
-[assembly: AssemblyTitle("Semmle.Autobuild.Cpp")]
-[assembly: AssemblyDescription("")]
-[assembly: AssemblyConfiguration("")]
-[assembly: AssemblyCompany("GitHub")]
-[assembly: AssemblyProduct("CodeQL autobuilder for C++")]
-[assembly: AssemblyCopyright("Copyright © GitHub 2020")]
-[assembly: AssemblyTrademark("")]
-[assembly: AssemblyCulture("")]
-
-// Setting ComVisible to false makes the types in this assembly not visible
-// to COM components.  If you need to access a type in this assembly from
-// COM, set the ComVisible attribute to true on that type.
-[assembly: ComVisible(false)]
-
-// Version information for an assembly consists of the following four values:
-//
-//      Major Version
-//      Minor Version
-//      Build Number
-//      Revision
-//
-// You can specify all the values or you can default the Build and Revision Numbers
-// by using the '*' as shown below:
-// [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.0.0.0")]
-[assembly: AssemblyFileVersion("1.0.0.0")]

cpp/autobuilder/Semmle.Autobuild.Cpp/Semmle.Autobuild.Cpp.csproj

@@ -1,28 +0,0 @@
-<Project Sdk="Microsoft.NET.Sdk">
-
-  <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
-    <AssemblyName>Semmle.Autobuild.Cpp</AssemblyName>
-    <RootNamespace>Semmle.Autobuild.Cpp</RootNamespace>
-    <ApplicationIcon />
-    <OutputType>Exe</OutputType>
-    <StartupObject />
-    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
-    <RuntimeIdentifiers>win-x64;linux-x64;osx-x64</RuntimeIdentifiers>
-    <Nullable>enable</Nullable>
-  </PropertyGroup>
-
-  <ItemGroup>
-    <Folder Include="Properties\" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <PackageReference Include="Microsoft.Build" Version="17.8.3" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <ProjectReference Include="..\..\..\csharp\extractor\Semmle.Util\Semmle.Util.csproj" />
-    <ProjectReference Include="..\..\..\csharp\autobuilder\Semmle.Autobuild.Shared\Semmle.Autobuild.Shared.csproj" />
-  </ItemGroup>
-
-</Project>

cpp/downgrades/19887dbd33327fb07d54251786e0cb2578539775/upgrade.properties

@@ -1,4 +1,4 @@
 description: Revert support for repeated initializers, which are allowed in C with designated initializers.
 compatibility: full
-aggregate_field_init.rel: reorder aggregate_field_init.rel (int aggregate, int initializer, int field, int position) aggregate initializer field
-aggregate_array_init.rel: reorder aggregate_array_init.rel (int aggregate, int initializer, int element_index, int position) aggregate initializer element_index
+aggregate_field_init.rel: reorder aggregate_field_init.rel (@aggregateliteral aggregate, @expr initializer, @membervariable field, int position) aggregate initializer field
+aggregate_array_init.rel: reorder aggregate_array_init.rel (@aggregateliteral aggregate, @expr initializer, int element_index, int position) aggregate initializer element_index

cpp/downgrades/BUILD.bazel

@@ -6,7 +6,7 @@ pkg_files(
         ["**"],
         exclude = ["BUILD.bazel"],
     ),
-    prefix = "cpp/downgrades",
+    prefix = "downgrades",
     strip_prefix = strip_prefix.from_pkg(),
     visibility = ["//cpp:__pkg__"],
 )

cpp/ql/lib/BUILD.bazel

@@ -5,11 +5,9 @@ package(default_visibility = ["//cpp:__pkg__"])
 pkg_files(
     name = "dbscheme",
     srcs = ["semmlecode.cpp.dbscheme"],
-    prefix = "cpp",
 )
 
 pkg_files(
     name = "dbscheme-stats",
     srcs = ["semmlecode.cpp.dbscheme.stats"],
-    prefix = "cpp",
 )

cpp/ql/lib/CHANGELOG.md

@@ -1,3 +1,23 @@
+## 1.1.0
+
+### New Features
+
+* Data models can now be added with data extensions. In this way source, sink and summary models can be added in extension `.model.yml` files, rather than by writing classes in QL code. New models should be added in the `lib/ext` folder.
+
+### Minor Analysis Improvements
+
+* A partial model for the `Boost.Asio` network library has been added. This includes sources, sinks and summaries for certain functions in `Boost.Asio`, such as `read_until` and `write`.
+
+## 1.0.0
+
+### Breaking Changes
+
+* CodeQL package management is now generally available, and all GitHub-produced CodeQL packages have had their version numbers increased to 1.0.0.
+
+## 0.13.1
+
+No user-facing changes.
+
 ## 0.13.0
 
 ### Breaking Changes

cpp/ql/lib/change-notes/released/0.13.1.md

@@ -0,0 +1,3 @@
+## 0.13.1
+
+No user-facing changes.

cpp/ql/lib/change-notes/released/1.0.0.md

@@ -0,0 +1,5 @@
+## 1.0.0
+
+### Breaking Changes
+
+* CodeQL package management is now generally available, and all GitHub-produced CodeQL packages have had their version numbers increased to 1.0.0.

cpp/ql/lib/change-notes/released/1.1.0.md

@@ -0,0 +1,9 @@
+## 1.1.0
+
+### New Features
+
+* Data models can now be added with data extensions. In this way source, sink and summary models can be added in extension `.model.yml` files, rather than by writing classes in QL code. New models should be added in the `lib/ext` folder.
+
+### Minor Analysis Improvements
+
+* A partial model for the `Boost.Asio` network library has been added. This includes sources, sinks and summaries for certain functions in `Boost.Asio`, such as `read_until` and `write`.

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

@@ -1,2 +1,2 @@
 ---
-lastReleaseVersion: 0.13.0
+lastReleaseVersion: 1.1.0

cpp/ql/lib/ext/Boost.Asio.model.yml

@@ -0,0 +1,26 @@
+extensions:
+  # partial model of the Boost::Asio network library
+extensions:
+  - addsTo:
+      pack: codeql/cpp-all
+      extensible: sourceModel
+    data: # namespace, type, subtypes, name, signature, ext, output, kind, provenance
+      - ["boost::asio", "", False, "read", "", "", "Argument[*1]", "remote", "manual"]
+      - ["boost::asio", "", False, "read_at", "", "", "Argument[*2]", "remote", "manual"]
+      - ["boost::asio", "", False, "read_until", "", "", "Argument[*1]", "remote", "manual"]
+      - ["boost::asio", "", False, "async_read", "", "", "Argument[*1]", "remote", "manual"]
+      - ["boost::asio", "", False, "async_read_at", "", "", "Argument[*2]", "remote", "manual"]
+      - ["boost::asio", "", False, "async_read_until", "", "", "Argument[*1]", "remote", "manual"]
+  - addsTo:
+      pack: codeql/cpp-all
+      extensible: sinkModel
+    data: # namespace, type, subtypes, name, signature, ext, input, kind, provenance
+      - ["boost::asio", "", False, "write", "", "", "Argument[*1]", "remote-sink", "manual"]
+      - ["boost::asio", "", False, "write_at", "", "", "Argument[*2]", "remote-sink", "manual"]
+      - ["boost::asio", "", False, "async_write", "", "", "Argument[*1]", "remote-sink", "manual"]
+      - ["boost::asio", "", False, "async_write_at", "", "", "Argument[*2]", "remote-sink", "manual"]
+  - addsTo:
+      pack: codeql/cpp-all
+      extensible: summaryModel
+    data: # namespace, type, subtypes, name, signature, ext, input, output, kind, provenance
+      - ["boost::asio", "", False, "buffer", "", "", "Argument[*0]", "ReturnValue", "taint", "manual"]

cpp/ql/lib/ext/empty.model.yml

@@ -0,0 +1,15 @@
+extensions:
+  # Make sure that the extensible model predicates have at least one definition
+  # to avoid errors about undefined extensionals.
+  - addsTo:
+      pack: codeql/cpp-all
+      extensible: sourceModel
+    data: []
+  - addsTo:
+      pack: codeql/cpp-all
+      extensible: sinkModel
+    data: []
+  - addsTo:
+      pack: codeql/cpp-all
+      extensible: summaryModel
+    data: []

cpp/ql/lib/qlpack.yml

@@ -1,5 +1,5 @@
 name: codeql/cpp-all
-version: 0.13.0
+version: 1.1.0
 groups: cpp
 dbscheme: semmlecode.cpp.dbscheme
 extractor: cpp
@@ -14,4 +14,6 @@ dependencies:
   codeql/tutorial: ${workspace}
   codeql/util: ${workspace}
   codeql/xml: ${workspace}
+dataExtensions:
+  - ext/*.model.yml
 warnOnImplicitThis: true

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

@@ -410,6 +410,10 @@ class LocalVariable extends LocalScopeVariable, @localvariable {
     or
     orphaned_variables(underlyingElement(this), unresolveElement(result))
   }
+
+  override predicate isStatic() {
+    super.isStatic() or orphaned_variables(underlyingElement(this), _)
+  }
 }
 
 /**

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

@@ -375,6 +375,33 @@ cached
 class IRGuardCondition extends Instruction {
   Instruction branch;
 
+  /*
+   * An `IRGuardCondition` supports reasoning about four different kinds of
+   * relations:
+   * 1. A unary equality relation of the form `e == k`
+   * 2. A binary equality relation of the form `e1 == e2 + k`
+   * 3. A unary inequality relation of the form `e < k`
+   * 4. A binary inequality relation of the form `e1 < e2 + k`
+   *
+   * where `k` is a constant.
+   *
+   * Furthermore, the unary relations (i.e., case 1 and case 3) are also
+   * inferred from `switch` statement guards: equality relations are inferred
+   * from the unique `case` statement, if any, and inequality relations are
+   * inferred from the [case range](https://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html)
+   * gcc extension.
+   *
+   * The implementation of all four follows the same structure: Each relation
+   * has a cached user-facing predicate that. For example,
+   * `GuardCondition::comparesEq` calls `compares_eq`. This predicate has
+   * several cases that recursively decompose the relation to bring it to a
+   * canonical form (i.e., a relation of the form `e1 == e2 + k`). The base
+   * case for this relation (i.e., `simple_comparison_eq`) handles
+   * `CompareEQInstruction`s and `CompareNEInstruction`, and recursive
+   * predicates (e.g., `complex_eq`) rewrites larger expressions such as
+   * `e1 + k1 == e2 + k2` into canonical the form `e1 == e2 + (k2 - k1)`.
+   */
+
   cached
   IRGuardCondition() { branch = getBranchForCondition(this) }
 
@@ -565,7 +592,7 @@ class IRGuardCondition extends Instruction {
   /** Holds if (determined by this guard) `op == k` evaluates to `areEqual` if this expression evaluates to `value`. */
   cached
   predicate comparesEq(Operand op, int k, boolean areEqual, AbstractValue value) {
-    compares_eq(this, op, k, areEqual, value)
+    unary_compares_eq(this, op, k, areEqual, false, value)
   }
 
   /**
@@ -586,7 +613,7 @@ class IRGuardCondition extends Instruction {
   cached
   predicate ensuresEq(Operand op, int k, IRBlock block, boolean areEqual) {
     exists(AbstractValue value |
-      compares_eq(this, op, k, areEqual, value) and this.valueControls(block, value)
+      unary_compares_eq(this, op, k, areEqual, false, value) and this.valueControls(block, value)
     )
   }
 
@@ -611,7 +638,7 @@ class IRGuardCondition extends Instruction {
   cached
   predicate ensuresEqEdge(Operand op, int k, IRBlock pred, IRBlock succ, boolean areEqual) {
     exists(AbstractValue value |
-      compares_eq(this, op, k, areEqual, value) and
+      unary_compares_eq(this, op, k, areEqual, false, value) and
       this.valueControlsEdge(pred, succ, value)
     )
   }
@@ -737,26 +764,68 @@ private predicate compares_eq(
   )
 }
 
-/** Holds if `op == k` is `areEqual` given that `test` is equal to `value`. */
-private predicate compares_eq(
-  Instruction test, Operand op, int k, boolean areEqual, AbstractValue value
+/**
+ * Holds if `op == k` is `areEqual` given that `test` is equal to `value`.
+ *
+ * Many internal predicates in this file have a `inNonZeroCase` column.
+ * Ideally, the `k` column would be a type such as `Option<int>::Option`, to
+ * represent whether we have a concrete value `k` such that `op == k`, or whether
+ * we only know that `op != 0`.
+ * However, cannot instantiate `Option` with an infinite type. Thus the boolean
+ * `inNonZeroCase` is used to distinquish the `Some` (where we have a concrete
+ * value `k`) and `None` cases (where we only know that `op != 0`).
+ *
+ * Thus, if `inNonZeroCase = true` then `op != 0` and the value of `k` is
+ * meaningless.
+ *
+ * To see why `inNonZeroCase` is needed consider the following C program:
+ * ```c
+ * char* p = ...;
+ * if(p) {
+ *   use(p);
+ * }
+ * ```
+ * in C++ there would be an int-to-bool conversion on `p`. However, since C
+ * does not have booleans there is no conversion. We want to be able to
+ * conclude that `p` is non-zero in the true branch, so we need to give `k`
+ * some value. However, simply setting `k = 1` would make the rest of the
+ * analysis think that `k == 1` holds inside the branch. So we distinquish
+ * between the above case and
+ * ```c
+ * if(p == 1) {
+ *   use(p)
+ * }
+ * ```
+ * by setting `inNonZeroCase` to `true` in the former case, but not in the
+ * latter.
+ */
+private predicate unary_compares_eq(
+  Instruction test, Operand op, int k, boolean areEqual, boolean inNonZeroCase, AbstractValue value
 ) {
   /* The simple case where the test *is* the comparison so areEqual = testIsTrue xor eq. */
-  exists(AbstractValue v | simple_comparison_eq(test, op, k, v) |
+  exists(AbstractValue v |
+    unary_simple_comparison_eq(test, k, inNonZeroCase, v) and op.getDef() = test
+  |
     areEqual = true and value = v
     or
     areEqual = false and value = v.getDualValue()
   )
   or
-  complex_eq(test, op, k, areEqual, value)
+  unary_complex_eq(test, op, k, areEqual, inNonZeroCase, value)
   or
   /* (x is true => (op == k)) => (!x is false => (op == k)) */
-  exists(AbstractValue dual | value = dual.getDualValue() |
-    compares_eq(test.(LogicalNotInstruction).getUnary(), op, k, areEqual, dual)
+  exists(AbstractValue dual, boolean inNonZeroCase0 |
+    value = dual.getDualValue() and
+    unary_compares_eq(test.(LogicalNotInstruction).getUnary(), op, k, inNonZeroCase0, areEqual, dual)
+  |
+    k = 0 and inNonZeroCase = inNonZeroCase0
+    or
+    k != 0 and inNonZeroCase = true
   )
   or
   // ((test is `areEqual` => op == const + k2) and const == `k1`) =>
   // test is `areEqual` => op == k1 + k2
+  inNonZeroCase = false and
   exists(int k1, int k2, ConstantInstruction const |
     compares_eq(test, op, const.getAUse(), k2, areEqual, value) and
     int_value(const) = k1 and
@@ -781,14 +850,63 @@ private predicate simple_comparison_eq(
   value.(BooleanValue).getValue() = false
 }
 
-/** Rearrange various simple comparisons into `op == k` form. */
-private predicate simple_comparison_eq(Instruction test, Operand op, int k, AbstractValue value) {
+/**
+ * Rearrange various simple comparisons into `op == k` form.
+ */
+private predicate unary_simple_comparison_eq(
+  Instruction test, int k, boolean inNonZeroCase, AbstractValue value
+) {
   exists(SwitchInstruction switch, CaseEdge case |
     test = switch.getExpression() and
-    op.getDef() = test and
     case = value.(MatchValue).getCase() and
     exists(switch.getSuccessor(case)) and
-    case.getValue().toInt() = k
+    case.getValue().toInt() = k and
+    inNonZeroCase = false
+  )
+  or
+  // Any instruction with an integral type could potentially be part of a
+  // check for nullness when used in a guard. So we include all integral
+  // typed instructions here. However, since some of these instructions are
+  // already included as guards in other cases, we exclude those here.
+  // These are instructions that compute a binary equality or inequality
+  // relation. For example, the following:
+  // ```cpp
+  // if(a == b + 42) { ... }
+  // ```
+  // generates the following IR:
+  // ```
+  // r1(glval<int>) = VariableAddress[a]     :
+  // r2(int)        = Load[a]                : &:r1, m1
+  // r3(glval<int>) = VariableAddress[b]     :
+  // r4(int)        = Load[b]                : &:r3, m2
+  // r5(int)        = Constant[42]           :
+  // r6(int)        = Add                    : r4, r5
+  // r7(bool)       = CompareEQ              : r2, r6
+  // v1(void)       = ConditionalBranch      : r7
+  // ```
+  // and since `r7` is an integral typed instruction this predicate could
+  // include a case for when `r7` evaluates to true (in which case we would
+  // infer that `r6` was non-zero, and a case for when `r7` evaluates to false
+  // (in which case we would infer that `r6` was zero).
+  // However, since `a == b + 42` is already supported when reasoning about
+  // binary equalities we exclude those cases here.
+  not test.isGLValue() and
+  not simple_comparison_eq(test, _, _, _, _) and
+  not simple_comparison_lt(test, _, _, _) and
+  not test = any(SwitchInstruction switch).getExpression() and
+  (
+    test.getResultIRType() instanceof IRAddressType or
+    test.getResultIRType() instanceof IRIntegerType or
+    test.getResultIRType() instanceof IRBooleanType
+  ) and
+  (
+    k = 1 and
+    value.(BooleanValue).getValue() = true and
+    inNonZeroCase = true
+    or
+    k = 0 and
+    value.(BooleanValue).getValue() = false and
+    inNonZeroCase = false
   )
 }
 
@@ -800,12 +918,12 @@ private predicate complex_eq(
   add_eq(cmp, left, right, k, areEqual, value)
 }
 
-private predicate complex_eq(
-  Instruction test, Operand op, int k, boolean areEqual, AbstractValue value
+private predicate unary_complex_eq(
+  Instruction test, Operand op, int k, boolean areEqual, boolean inNonZeroCase, AbstractValue value
 ) {
-  sub_eq(test, op, k, areEqual, value)
+  unary_sub_eq(test, op, k, areEqual, inNonZeroCase, value)
   or
-  add_eq(test, op, k, areEqual, value)
+  unary_add_eq(test, op, k, areEqual, inNonZeroCase, value)
 }
 
 /*
@@ -834,7 +952,8 @@ private predicate compares_lt(
 
 /** Holds if `op < k` evaluates to `isLt` given that `test` evaluates to `value`. */
 private predicate compares_lt(Instruction test, Operand op, int k, boolean isLt, AbstractValue value) {
-  simple_comparison_lt(test, op, k, isLt, value)
+  unary_simple_comparison_lt(test, k, isLt, value) and
+  op.getDef() = test
   or
   complex_lt(test, op, k, isLt, value)
   or
@@ -881,12 +1000,11 @@ private predicate simple_comparison_lt(CompareInstruction cmp, Operand left, Ope
 }
 
 /** Rearrange various simple comparisons into `op < k` form. */
-private predicate simple_comparison_lt(
-  Instruction test, Operand op, int k, boolean isLt, AbstractValue value
+private predicate unary_simple_comparison_lt(
+  Instruction test, int k, boolean isLt, AbstractValue value
 ) {
   exists(SwitchInstruction switch, CaseEdge case |
     test = switch.getExpression() and
-    op.getDef() = test and
     case = value.(MatchValue).getCase() and
     exists(switch.getSuccessor(case)) and
     case.getMaxValue() > case.getMinValue()
@@ -1069,16 +1187,20 @@ private predicate sub_eq(
 }
 
 // op - x == c => op == (c+x)
-private predicate sub_eq(Instruction test, Operand op, int k, boolean areEqual, AbstractValue value) {
+private predicate unary_sub_eq(
+  Instruction test, Operand op, int k, boolean areEqual, boolean inNonZeroCase, AbstractValue value
+) {
+  inNonZeroCase = false and
   exists(SubInstruction sub, int c, int x |
-    compares_eq(test, sub.getAUse(), c, areEqual, value) and
+    unary_compares_eq(test, sub.getAUse(), c, areEqual, inNonZeroCase, value) and
     op = sub.getLeftOperand() and
     x = int_value(sub.getRight()) and
     k = c + x
   )
   or
+  inNonZeroCase = false and
   exists(PointerSubInstruction sub, int c, int x |
-    compares_eq(test, sub.getAUse(), c, areEqual, value) and
+    unary_compares_eq(test, sub.getAUse(), c, areEqual, inNonZeroCase, value) and
     op = sub.getLeftOperand() and
     x = int_value(sub.getRight()) and
     k = c + x
@@ -1132,11 +1254,13 @@ private predicate add_eq(
 }
 
 // left + x == right + c => left == right + (c-x)
-private predicate add_eq(
-  Instruction test, Operand left, int k, boolean areEqual, AbstractValue value
+private predicate unary_add_eq(
+  Instruction test, Operand left, int k, boolean areEqual, boolean inNonZeroCase,
+  AbstractValue value
 ) {
+  inNonZeroCase = false and
   exists(AddInstruction lhs, int c, int x |
-    compares_eq(test, lhs.getAUse(), c, areEqual, value) and
+    unary_compares_eq(test, lhs.getAUse(), c, areEqual, inNonZeroCase, value) and
     (
       left = lhs.getLeftOperand() and x = int_value(lhs.getRight())
       or
@@ -1145,8 +1269,9 @@ private predicate add_eq(
     k = c - x
   )
   or
+  inNonZeroCase = false and
   exists(PointerAddInstruction lhs, int c, int x |
-    compares_eq(test, lhs.getAUse(), c, areEqual, value) and
+    unary_compares_eq(test, lhs.getAUse(), c, areEqual, inNonZeroCase, value) and
     (
       left = lhs.getLeftOperand() and x = int_value(lhs.getRight())
       or

cpp/ql/lib/semmle/code/cpp/dataflow/ExternalFlow.qll

@@ -78,6 +78,7 @@ private import internal.FlowSummaryImpl
 private import internal.FlowSummaryImpl::Public
 private import internal.FlowSummaryImpl::Private
 private import internal.FlowSummaryImpl::Private::External
+private import internal.ExternalFlowExtensions as Extensions
 private import codeql.mad.ModelValidation as SharedModelVal
 private import codeql.util.Unit
 
@@ -138,6 +139,9 @@ predicate sourceModel(
     row.splitAt(";", 7) = kind
   ) and
   provenance = "manual"
+  or
+  Extensions::sourceModel(namespace, type, subtypes, name, signature, ext, output, kind, provenance,
+    _)
 }
 
 /** Holds if a sink model exists for the given parameters. */
@@ -158,6 +162,8 @@ predicate sinkModel(
     row.splitAt(";", 7) = kind
   ) and
   provenance = "manual"
+  or
+  Extensions::sinkModel(namespace, type, subtypes, name, signature, ext, input, kind, provenance, _)
 }
 
 /** Holds if a summary model exists for the given parameters. */
@@ -179,6 +185,9 @@ predicate summaryModel(
     row.splitAt(";", 8) = kind
   ) and
   provenance = "manual"
+  or
+  Extensions::summaryModel(namespace, type, subtypes, name, signature, ext, input, output, kind,
+    provenance, _)
 }
 
 private predicate relevantNamespace(string namespace) {
@@ -203,8 +212,10 @@ private predicate canonicalNamespaceLink(string namespace, string subns) {
 }
 
 /**
- * Holds if CSV framework coverage of `namespace` is `n` api endpoints of the
- * kind `(kind, part)`.
+ * Holds if MaD framework coverage of `namespace` is `n` api endpoints of the
+ * kind `(kind, part)`, and `namespaces` is the number of subnamespaces of
+ * `namespace` which have MaD framework coverage (including `namespace`
+ * itself).
  */
 predicate modelCoverage(string namespace, int namespaces, string kind, string part, int n) {
   namespaces = strictcount(string subns | canonicalNamespaceLink(namespace, subns)) and
@@ -321,10 +332,10 @@ module CsvValidation {
       or
       summaryModel(namespace, type, _, name, signature, ext, _, _, _, _) and pred = "summary"
     |
-      not namespace.regexpMatch("[a-zA-Z0-9_\\.]+") and
+      not namespace.regexpMatch("[a-zA-Z0-9_\\.:]*") and
       result = "Dubious namespace \"" + namespace + "\" in " + pred + " model."
       or
-      not type.regexpMatch("[a-zA-Z0-9_<>,\\+]+") and
+      not type.regexpMatch("[a-zA-Z0-9_<>,\\+]*") and
       result = "Dubious type \"" + type + "\" in " + pred + " model."
       or
       not name.regexpMatch("[a-zA-Z0-9_<>,]*") and

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

@@ -9,7 +9,7 @@ private import DataFlowUtil
 /**
  * Gets a function that might be called by `call`.
  */
-Function viableCallable(DataFlowCall call) {
+DataFlowCallable viableCallable(DataFlowCall call) {
   result = call.(Call).getTarget()
   or
   // If the target of the call does not have a body in the snapshot, it might

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

@@ -242,7 +242,17 @@ class CastNode extends Node {
   CastNode() { none() } // stub implementation
 }
 
-class DataFlowCallable = Function;
+class DataFlowCallable extends Function {
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCallable c, string file, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(file, startline, startcolumn, _, _)
+      |
+        c order by file, startline, startcolumn
+      )
+  }
+}
 
 class DataFlowExpr = Expr;
 
@@ -261,10 +271,28 @@ class DataFlowCall extends Expr instanceof Call {
   ExprNode getNode() { result.getExpr() = this }
 
   /** Gets the enclosing callable of this call. */
-  Function getEnclosingCallable() { result = this.getEnclosingFunction() }
+  DataFlowCallable getEnclosingCallable() { result = this.getEnclosingFunction() }
+
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCall c, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(_, startline, startcolumn, _, _)
+      |
+        c order by startline, startcolumn
+      )
+  }
 }
 
-predicate isUnreachableInCall(Node n, DataFlowCall call) { none() } // stub implementation
+class NodeRegion instanceof Unit {
+  string toString() { result = "NodeRegion" }
+
+  predicate contains(Node n) { none() }
+
+  int totalOrder() { result = 1 }
+}
+
+predicate isUnreachableInCall(NodeRegion nr, DataFlowCall call) { none() } // stub implementation
 
 /**
  * Holds if access paths with `c` at their head always should be tracked at high

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

@@ -0,0 +1,27 @@
+/**
+ * This module provides extensible predicates for defining MaD models.
+ */
+
+/**
+ * Holds if an external source model exists for the given parameters.
+ */
+extensible predicate sourceModel(
+  string namespace, string type, boolean subtypes, string name, string signature, string ext,
+  string output, string kind, string provenance, QlBuiltins::ExtensionId madId
+);
+
+/**
+ * Holds if an external sink model exists for the given parameters.
+ */
+extensible predicate sinkModel(
+  string namespace, string type, boolean subtypes, string name, string signature, string ext,
+  string input, string kind, string provenance, QlBuiltins::ExtensionId madId
+);
+
+/**
+ * Holds if an external summary model exists for the given parameters.
+ */
+extensible predicate summaryModel(
+  string namespace, string type, boolean subtypes, string name, string signature, string ext,
+  string input, string output, string kind, string provenance, QlBuiltins::ExtensionId madId
+);

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

@@ -1062,6 +1062,16 @@ class DataFlowCallable extends TDataFlowCallable {
     result = this.asSummarizedCallable() or // SummarizedCallable = Function (in CPP)
     result = this.asSourceCallable()
   }
+
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCallable c, string file, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(file, startline, startcolumn, _, _)
+      |
+        c order by file, startline, startcolumn
+      )
+  }
 }
 
 /**
@@ -1159,6 +1169,16 @@ class DataFlowCall extends TDataFlowCall {
    * Gets the location of this call.
    */
   Location getLocation() { none() }
+
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCall c, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(_, startline, startcolumn, _, _)
+      |
+        c order by startline, startcolumn
+      )
+  }
 }
 
 /**
@@ -1247,43 +1267,53 @@ module IsUnreachableInCall {
     any(G::IRGuardCondition guard).ensuresLt(left, right, k, block, areEqual)
   }
 
-  predicate isUnreachableInCall(Node n, DataFlowCall call) {
+  class NodeRegion instanceof IRBlock {
+    string toString() { result = "NodeRegion" }
+
+    predicate contains(Node n) { this = n.getBasicBlock() }
+
+    int totalOrder() {
+      this =
+        rank[result](IRBlock b, int startline, int startcolumn |
+          b.getLocation().hasLocationInfo(_, startline, startcolumn, _, _)
+        |
+          b order by startline, startcolumn
+        )
+    }
+  }
+
+  predicate isUnreachableInCall(NodeRegion block, DataFlowCall call) {
     exists(
       InstructionDirectParameterNode paramNode, ConstantIntegralTypeArgumentNode arg,
-      IntegerConstantInstruction constant, int k, Operand left, Operand right, IRBlock block
+      IntegerConstantInstruction constant, int k, Operand left, Operand right, int argval
     |
       // arg flows into `paramNode`
-      DataFlowImplCommon::viableParamArg(call, paramNode, arg) and
+      DataFlowImplCommon::viableParamArg(call, pragma[only_bind_into](paramNode),
+        pragma[only_bind_into](arg)) and
       left = constant.getAUse() and
       right = valueNumber(paramNode.getInstruction()).getAUse() and
-      block = n.getBasicBlock()
+      argval = arg.getValue()
     |
       // and there's a guard condition which ensures that the result of `left == right + k` is `areEqual`
-      exists(boolean areEqual |
-        ensuresEq(pragma[only_bind_into](left), pragma[only_bind_into](right),
-          pragma[only_bind_into](k), pragma[only_bind_into](block), areEqual)
-      |
+      exists(boolean areEqual | ensuresEq(left, right, k, block, areEqual) |
         // this block ensures that left = right + k, but it holds that `left != right + k`
         areEqual = true and
-        constant.getValue().toInt() != arg.getValue() + k
+        constant.getValue().toInt() != argval + k
         or
         // this block ensures that or `left != right + k`, but it holds that `left = right + k`
         areEqual = false and
-        constant.getValue().toInt() = arg.getValue() + k
+        constant.getValue().toInt() = argval + k
       )
       or
       // or there's a guard condition which ensures that the result of `left < right + k` is `isLessThan`
-      exists(boolean isLessThan |
-        ensuresLt(pragma[only_bind_into](left), pragma[only_bind_into](right),
-          pragma[only_bind_into](k), pragma[only_bind_into](block), isLessThan)
-      |
+      exists(boolean isLessThan | ensuresLt(left, right, k, block, isLessThan) |
         isLessThan = true and
         // this block ensures that `left < right + k`, but it holds that `left >= right + k`
-        constant.getValue().toInt() >= arg.getValue() + k
+        constant.getValue().toInt() >= argval + k
         or
         // this block ensures that `left >= right + k`, but it holds that `left < right + k`
         isLessThan = false and
-        constant.getValue().toInt() < arg.getValue() + k
+        constant.getValue().toInt() < argval + k
       )
     )
   }
@@ -1306,6 +1336,8 @@ predicate nodeIsHidden(Node n) {
   n instanceof FinalGlobalValue
   or
   n instanceof InitialGlobalValue
+  or
+  n instanceof SsaPhiInputNode
 }
 
 predicate neverSkipInPathGraph(Node n) {
@@ -1604,6 +1636,8 @@ private Instruction getAnInstruction(Node n) {
   or
   result = n.(SsaPhiNode).getPhiNode().getBasicBlock().getFirstInstruction()
   or
+  result = n.(SsaPhiInputNode).getBasicBlock().getFirstInstruction()
+  or
   n.(IndirectInstruction).hasInstructionAndIndirectionIndex(result, _)
   or
   not n instanceof IndirectInstruction and
@@ -1665,3 +1699,311 @@ class DataFlowSecondLevelScope extends TDataFlowSecondLevelScope {
 
 /** Gets the second-level scope containing the node `n`, if any. */
 DataFlowSecondLevelScope getSecondLevelScope(Node n) { result.getANode() = n }
+
+/**
+ * Module that defines flow through iterators.
+ * For example,
+ * ```cpp
+ * auto it = v.begin();
+ * *it = source();
+ * ...
+ * sink(v[0]);
+ * ```
+ */
+module IteratorFlow {
+  private import codeql.ssa.Ssa as SsaImpl
+  private import semmle.code.cpp.models.interfaces.Iterator as Interface
+  private import semmle.code.cpp.models.implementations.Iterator as Impl
+
+  /**
+   * A variable of some type that can produce an iterator.
+   */
+  class SourceVariable extends Ssa::SourceVariable {
+    SourceVariable() {
+      exists(Interface::GetIteratorFunction gets, Cpp::FunctionInput input, int i |
+        input.isParameterDerefOrQualifierObject(i) and
+        gets.getsIterator(input, _)
+      |
+        this.getType().stripType() = gets.getParameter(i).getType().stripType()
+        or
+        i = -1 and
+        this.getType().stripType() = gets.getDeclaringType()
+      )
+    }
+  }
+
+  private module SsaInput implements SsaImpl::InputSig<Location> {
+    import Ssa::InputSigCommon
+
+    class SourceVariable = IteratorFlow::SourceVariable;
+
+    /** A call to function that dereferences an iterator. */
+    private class IteratorPointerDereferenceCall extends CallInstruction {
+      IteratorPointerDereferenceCall() {
+        this.getStaticCallTarget() instanceof Impl::IteratorPointerDereferenceOperator
+      }
+    }
+
+    /** A call to a function that obtains an iterator. */
+    private class GetsIteratorCall extends CallInstruction {
+      GetsIteratorCall() { this.getStaticCallTarget() instanceof Impl::GetIteratorFunction }
+    }
+
+    /** A call to `operator++` or `operator--` on an iterator. */
+    private class IteratorCrementCall extends CallInstruction {
+      IteratorCrementCall() { this.getStaticCallTarget() instanceof Impl::IteratorCrementOperator }
+    }
+
+    /**
+     * Gets an ultimate definition of `def`.
+     *
+     * Note: Unlike `def.getAnUltimateDefinition()` this predicate also
+     * traverses back through iterator increment and decrement operations.
+     */
+    private Ssa::Def getAnUltimateDefinition(Ssa::Def def) {
+      result = def.getAnUltimateDefinition()
+      or
+      exists(IRBlock bb, int i, IteratorCrementCall crementCall, Ssa::SourceVariable sv |
+        crementCall = def.getValue().asInstruction().(StoreInstruction).getSourceValue() and
+        sv = def.getSourceVariable() and
+        bb.getInstruction(i) = crementCall and
+        Ssa::ssaDefReachesReadExt(sv, result.asDef(), bb, i)
+      )
+    }
+
+    /**
+     * Holds if `write` is an instruction that writes to address `address`
+     */
+    private predicate isIteratorWrite(Instruction write, Operand address) {
+      exists(Ssa::DefImpl writeDef, IRBlock bb, int i |
+        writeDef.hasIndexInBlock(bb, i, _) and
+        bb.getInstruction(i) = write and
+        address = writeDef.getAddressOperand()
+      )
+    }
+
+    /**
+     * Holds if `writeToDeref` is a write to an iterator that was obtained
+     * by `beginCall`. That is, the following instruction sequence holds:
+     * ```cpp
+     * it = container.begin(); // or a similar iterator-obtaining function call
+     * ...
+     * *it = value;
+     * ```
+     */
+    private predicate isIteratorStoreInstruction(
+      GetsIteratorCall beginCall, Instruction writeToDeref
+    ) {
+      exists(
+        StoreInstruction beginStore, IRBlock bbStar, int iStar, Ssa::Def def,
+        IteratorPointerDereferenceCall starCall, Ssa::Def ultimate, Operand address
+      |
+        isIteratorWrite(writeToDeref, address) and
+        operandForFullyConvertedCall(address, starCall) and
+        bbStar.getInstruction(iStar) = starCall and
+        Ssa::ssaDefReachesReadExt(_, def.asDef(), bbStar, iStar) and
+        ultimate = getAnUltimateDefinition*(def) and
+        beginStore = ultimate.getValue().asInstruction() and
+        operandForFullyConvertedCall(beginStore.getSourceValueOperand(), beginCall)
+      )
+    }
+
+    /**
+     * Holds if `(bb, i)` contains a write to an iterator that may have been obtained
+     * by calling `begin` (or related functions) on the variable `v`.
+     */
+    predicate variableWrite(IRBlock bb, int i, SourceVariable v, boolean certain) {
+      certain = false and
+      exists(GetsIteratorCall beginCall, Instruction writeToDeref, IRBlock bbQual, int iQual |
+        isIteratorStoreInstruction(beginCall, writeToDeref) and
+        bb.getInstruction(i) = writeToDeref and
+        bbQual.getInstruction(iQual) = beginCall and
+        Ssa::variableRead(bbQual, iQual, v, _)
+      )
+    }
+
+    /** Holds if `(bb, i)` reads the container variable `v`. */
+    predicate variableRead(IRBlock bb, int i, SourceVariable v, boolean certain) {
+      Ssa::variableRead(bb, i, v, certain)
+    }
+  }
+
+  private module IteratorSsa = SsaImpl::Make<Location, SsaInput>;
+
+  cached
+  private newtype TSsaDef =
+    TDef(IteratorSsa::DefinitionExt def) or
+    TPhi(PhiNode phi)
+
+  abstract private class SsaDef extends TSsaDef {
+    /** Gets a textual representation of this element. */
+    string toString() { none() }
+
+    /** Gets the underlying non-phi definition or use. */
+    IteratorSsa::DefinitionExt asDef() { none() }
+
+    /** Gets the underlying phi node. */
+    PhiNode asPhi() { none() }
+
+    /** Gets the location of this element. */
+    abstract Location getLocation();
+  }
+
+  private class Def extends TDef, SsaDef {
+    IteratorSsa::DefinitionExt def;
+
+    Def() { this = TDef(def) }
+
+    final override IteratorSsa::DefinitionExt asDef() { result = def }
+
+    final override Location getLocation() { result = this.getImpl().getLocation() }
+
+    /** Gets the variable written to by this definition. */
+    final SourceVariable getSourceVariable() { result = def.getSourceVariable() }
+
+    override string toString() { result = def.toString() }
+
+    /**
+     * Holds if this definition (or use) has index `index` in block `block`,
+     * and is a definition (or use) of the variable `sv`.
+     */
+    predicate hasIndexInBlock(IRBlock block, int index, SourceVariable sv) {
+      def.definesAt(sv, block, index, _)
+    }
+
+    private Ssa::DefImpl getImpl() {
+      exists(IRBlock bb, int i |
+        this.hasIndexInBlock(bb, i, _) and
+        result.hasIndexInBlock(bb, i)
+      )
+    }
+
+    /** Gets the value written by this definition (i.e., the "right-hand side"). */
+    Node0Impl getValue() { result = this.getImpl().getValue() }
+
+    /** Gets the indirection index of this definition. */
+    int getIndirectionIndex() { result = this.getImpl().getIndirectionIndex() }
+  }
+
+  private class Phi extends TPhi, SsaDef {
+    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.toString() }
+
+    SsaIteratorNode getNode() { result.getIteratorFlowNode() = phi }
+  }
+
+  private class PhiNode extends IteratorSsa::DefinitionExt {
+    PhiNode() {
+      this instanceof IteratorSsa::PhiNode or
+      this instanceof IteratorSsa::PhiReadNode
+    }
+
+    SsaIteratorNode getNode() { result.getIteratorFlowNode() = this }
+  }
+
+  cached
+  private module IteratorSsaCached {
+    cached
+    predicate adjacentDefRead(IRBlock bb1, int i1, SourceVariable sv, IRBlock bb2, int i2) {
+      IteratorSsa::adjacentDefReadExt(_, sv, bb1, i1, bb2, i2)
+      or
+      exists(PhiNode phi |
+        IteratorSsa::lastRefRedefExt(_, sv, bb1, i1, phi) and
+        phi.definesAt(sv, bb2, i2, _)
+      )
+    }
+
+    cached
+    Node getAPriorDefinition(IteratorSsa::DefinitionExt next) {
+      exists(IRBlock bb, int i, SourceVariable sv, IteratorSsa::DefinitionExt def |
+        IteratorSsa::lastRefRedefExt(pragma[only_bind_into](def), pragma[only_bind_into](sv),
+          pragma[only_bind_into](bb), pragma[only_bind_into](i), next) and
+        nodeToDefOrUse(result, sv, bb, i, _)
+      )
+    }
+  }
+
+  /** The set of nodes necessary for iterator flow. */
+  class IteratorFlowNode instanceof PhiNode {
+    /** Gets a textual representation of this node. */
+    string toString() { result = super.toString() }
+
+    /** Gets the type of this node. */
+    DataFlowType getType() {
+      exists(Ssa::SourceVariable sv |
+        super.definesAt(sv, _, _, _) and
+        result = sv.getType()
+      )
+    }
+
+    /** Gets the `Declaration` that contains this block. */
+    Declaration getFunction() { result = super.getBasicBlock().getEnclosingFunction() }
+
+    /** Gets the locatino of this node. */
+    Location getLocation() { result = super.getBasicBlock().getLocation() }
+  }
+
+  private import IteratorSsaCached
+
+  private predicate defToNode(Node node, Def def, boolean uncertain) {
+    (
+      nodeHasOperand(node, def.getValue().asOperand(), def.getIndirectionIndex())
+      or
+      nodeHasInstruction(node, def.getValue().asInstruction(), def.getIndirectionIndex())
+    ) and
+    uncertain = false
+  }
+
+  private predicate nodeToDefOrUse(
+    Node node, SourceVariable sv, IRBlock bb, int i, boolean uncertain
+  ) {
+    exists(Def def |
+      def.hasIndexInBlock(bb, i, sv) and
+      defToNode(node, def, uncertain)
+    )
+    or
+    useToNode(bb, i, sv, node) and
+    uncertain = false
+  }
+
+  private predicate useToNode(IRBlock bb, int i, SourceVariable sv, Node nodeTo) {
+    exists(PhiNode phi |
+      phi.definesAt(sv, bb, i, _) and
+      nodeTo = phi.getNode()
+    )
+    or
+    exists(Ssa::UseImpl use |
+      use.hasIndexInBlock(bb, i, sv) and
+      nodeTo = use.getNode()
+    )
+  }
+
+  /**
+   * Holds if `nodeFrom` flows to `nodeTo` in a single step.
+   */
+  predicate localFlowStep(Node nodeFrom, Node nodeTo) {
+    exists(
+      Node nFrom, SourceVariable sv, IRBlock bb1, int i1, IRBlock bb2, int i2, boolean uncertain
+    |
+      adjacentDefRead(bb1, i1, sv, bb2, i2) and
+      nodeToDefOrUse(nFrom, sv, bb1, i1, uncertain) and
+      useToNode(bb2, i2, sv, nodeTo)
+    |
+      if uncertain = true
+      then
+        nodeFrom =
+          [
+            nFrom,
+            getAPriorDefinition(any(IteratorSsa::DefinitionExt next | next.definesAt(sv, bb1, i1, _)))
+          ]
+      else nFrom = nodeFrom
+    )
+  }
+}

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowUtil.qll

@@ -45,7 +45,9 @@ private newtype TIRDataFlowNode =
     or
     Ssa::isModifiableByCall(operand, indirectionIndex)
   } or
+  TSsaPhiInputNode(Ssa::PhiNode phi, IRBlock input) { phi.hasInputFromBlock(_, _, _, _, input) } or
   TSsaPhiNode(Ssa::PhiNode phi) or
+  TSsaIteratorNode(IteratorFlow::IteratorFlowNode n) or
   TRawIndirectOperand0(Node0Impl node, int indirectionIndex) {
     Ssa::hasRawIndirectOperand(node.asOperand(), indirectionIndex)
   } or
@@ -113,6 +115,13 @@ predicate conversionFlow(
       instrTo.(CheckedConvertOrNullInstruction).getUnaryOperand() = opFrom
       or
       instrTo.(InheritanceConversionInstruction).getUnaryOperand() = opFrom
+      or
+      exists(BuiltInInstruction builtIn |
+        builtIn = instrTo and
+        // __builtin_bit_cast
+        builtIn.getBuiltInOperation() instanceof BuiltInBitCast and
+        opFrom = builtIn.getAnOperand()
+      )
     )
     or
     additional = true and
@@ -157,6 +166,12 @@ class Node extends TIRDataFlowNode {
   /** Gets the operands corresponding to this node, if any. */
   Operand asOperand() { result = this.(OperandNode).getOperand() }
 
+  /**
+   * Gets the operand that is indirectly tracked by this node behind `index`
+   * number of indirections.
+   */
+  Operand asIndirectOperand(int index) { hasOperandAndIndex(this, result, index) }
+
   /**
    * Holds if this node is at index `i` in basic block `block`.
    *
@@ -169,6 +184,9 @@ class Node extends TIRDataFlowNode {
     or
     this.(SsaPhiNode).getPhiNode().getBasicBlock() = block and i = -1
     or
+    this.(SsaPhiInputNode).getBlock() = block and
+    i = block.getInstructionCount()
+    or
     this.(RawIndirectOperand).getOperand().getUse() = block.getInstruction(i)
     or
     this.(RawIndirectInstruction).getInstruction() = block.getInstruction(i)
@@ -621,7 +639,7 @@ class SsaPhiNode extends Node, TSsaPhiNode {
 
   final override Location getLocationImpl() { result = phi.getBasicBlock().getLocation() }
 
-  override string toStringImpl() { result = "Phi" }
+  override string toStringImpl() { result = phi.toString() }
 
   /**
    * Gets a node that is used as input to this phi node.
@@ -630,7 +648,7 @@ class SsaPhiNode extends Node, TSsaPhiNode {
    */
   cached
   final Node getAnInput(boolean fromBackEdge) {
-    localFlowStep(result, this) and
+    result.(SsaPhiInputNode).getPhiNode() = phi and
     exists(IRBlock bPhi, IRBlock bResult |
       bPhi = phi.getBasicBlock() and bResult = result.getBasicBlock()
     |
@@ -653,6 +671,82 @@ class SsaPhiNode extends Node, TSsaPhiNode {
   predicate isPhiRead() { phi.isPhiRead() }
 }
 
+/**
+ * INTERNAL: Do not use.
+ *
+ * A node that is used as an input to a phi node.
+ *
+ * This class exists to allow more powerful barrier guards. Consider this
+ * example:
+ *
+ * ```cpp
+ * int x = source();
+ * if(!safe(x)) {
+ *   x = clear();
+ * }
+ * // phi node for x here
+ * sink(x);
+ * ```
+ *
+ * At the phi node for `x` it is neither the case that `x` is dominated by
+ * `safe(x)`, or is the case that the phi is dominated by a clearing of `x`.
+ *
+ * By inserting a "phi input" node as the last entry in the basic block that
+ * defines the inputs to the phi we can conclude that each of those inputs are
+ * safe to pass to `sink`.
+ */
+class SsaPhiInputNode extends Node, TSsaPhiInputNode {
+  Ssa::PhiNode phi;
+  IRBlock block;
+
+  SsaPhiInputNode() { this = TSsaPhiInputNode(phi, block) }
+
+  /** Gets the phi node associated with this node. */
+  Ssa::PhiNode getPhiNode() { result = phi }
+
+  /** Gets the basic block in which this input originates. */
+  IRBlock getBlock() { result = block }
+
+  override Declaration getEnclosingCallable() { result = this.getFunction() }
+
+  override Declaration getFunction() { result = phi.getBasicBlock().getEnclosingFunction() }
+
+  override DataFlowType getType() { result = this.getSourceVariable().getType() }
+
+  override predicate isGLValue() { phi.getSourceVariable().isGLValue() }
+
+  final override Location getLocationImpl() { result = block.getLastInstruction().getLocation() }
+
+  override string toStringImpl() { result = "Phi input" }
+
+  /** Gets the source variable underlying this phi node. */
+  Ssa::SourceVariable getSourceVariable() { result = phi.getSourceVariable() }
+}
+
+/**
+ * INTERNAL: do not use.
+ *
+ * Dataflow nodes necessary for iterator flow
+ */
+class SsaIteratorNode extends Node, TSsaIteratorNode {
+  IteratorFlow::IteratorFlowNode node;
+
+  SsaIteratorNode() { this = TSsaIteratorNode(node) }
+
+  /** Gets the phi node associated with this node. */
+  IteratorFlow::IteratorFlowNode getIteratorFlowNode() { result = node }
+
+  override Declaration getEnclosingCallable() { result = this.getFunction() }
+
+  override Declaration getFunction() { result = node.getFunction() }
+
+  override DataFlowType getType() { result = node.getType() }
+
+  final override Location getLocationImpl() { result = node.getLocation() }
+
+  override string toStringImpl() { result = node.toString() }
+}
+
 /**
  * INTERNAL: do not use.
  *
@@ -1190,11 +1284,11 @@ class UninitializedNode extends Node {
   LocalVariable v;
 
   UninitializedNode() {
-    exists(Ssa::Def def |
+    exists(Ssa::Def def, Ssa::SourceVariable sv |
       def.getIndirectionIndex() = 0 and
       def.getValue().asInstruction() instanceof UninitializedInstruction and
-      Ssa::nodeToDefOrUse(this, def, _) and
-      v = def.getSourceVariable().getBaseVariable().(Ssa::BaseIRVariable).getIRVariable().getAst()
+      Ssa::defToNode(this, def, sv, _, _, _) and
+      v = sv.getBaseVariable().(Ssa::BaseIRVariable).getIRVariable().getAst()
     )
   }
 
@@ -2151,6 +2245,11 @@ private module Cached {
       // Def-use/Use-use flow
       Ssa::ssaFlow(nodeFrom, nodeTo)
       or
+      // Phi input -> Phi
+      nodeFrom.(SsaPhiInputNode).getPhiNode() = nodeTo.(SsaPhiNode).getPhiNode()
+      or
+      IteratorFlow::localFlowStep(nodeFrom, nodeTo)
+      or
       // Operand -> Instruction flow
       simpleInstructionLocalFlowStep(nodeFrom.asOperand(), nodeTo.asInstruction())
       or
@@ -2587,6 +2686,22 @@ class ContentSet instanceof Content {
   }
 }
 
+pragma[nomagic]
+private predicate guardControlsPhiInput(
+  IRGuardCondition g, boolean branch, Ssa::Definition def, IRBlock input, Ssa::PhiNode phi
+) {
+  phi.hasInputFromBlock(def, _, _, _, input) and
+  (
+    g.controls(input, branch)
+    or
+    exists(EdgeKind kind |
+      g.getBlock() = input and
+      kind = getConditionalEdge(branch) and
+      input.getSuccessor(kind) = phi.getBasicBlock()
+    )
+  )
+}
+
 /**
  * Holds if the guard `g` validates the expression `e` upon evaluating to `branch`.
  *
@@ -2635,13 +2750,21 @@ module BarrierGuard<guardChecksSig/3 guardChecks> {
    *
    * NOTE: If an indirect expression is tracked, use `getAnIndirectBarrierNode` instead.
    */
-  ExprNode getABarrierNode() {
+  Node getABarrierNode() {
     exists(IRGuardCondition g, Expr e, ValueNumber value, boolean edge |
       e = value.getAnInstruction().getConvertedResultExpression() and
-      result.getConvertedExpr() = e and
+      result.asConvertedExpr() = e and
       guardChecks(g, value.getAnInstruction().getConvertedResultExpression(), edge) and
       g.controls(result.getBasicBlock(), edge)
     )
+    or
+    exists(
+      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input, Ssa::PhiNode phi
+    |
+      guardChecks(g, def.getARead().asOperand().getDef().getConvertedResultExpression(), branch) and
+      guardControlsPhiInput(g, branch, def, input, phi) and
+      result = TSsaPhiInputNode(phi, input)
+    )
   }
 
   /**
@@ -2677,7 +2800,7 @@ module BarrierGuard<guardChecksSig/3 guardChecks> {
    *
    * NOTE: If a non-indirect expression is tracked, use `getABarrierNode` instead.
    */
-  IndirectExprNode getAnIndirectBarrierNode() { result = getAnIndirectBarrierNode(_) }
+  Node getAnIndirectBarrierNode() { result = getAnIndirectBarrierNode(_) }
 
   /**
    * Gets an indirect expression node with indirection index `indirectionIndex` that is
@@ -2713,13 +2836,23 @@ module BarrierGuard<guardChecksSig/3 guardChecks> {
    *
    * NOTE: If a non-indirect expression is tracked, use `getABarrierNode` instead.
    */
-  IndirectExprNode getAnIndirectBarrierNode(int indirectionIndex) {
+  Node getAnIndirectBarrierNode(int indirectionIndex) {
     exists(IRGuardCondition g, Expr e, ValueNumber value, boolean edge |
       e = value.getAnInstruction().getConvertedResultExpression() and
-      result.getConvertedExpr(indirectionIndex) = e and
+      result.asIndirectConvertedExpr(indirectionIndex) = e and
       guardChecks(g, value.getAnInstruction().getConvertedResultExpression(), edge) and
       g.controls(result.getBasicBlock(), edge)
     )
+    or
+    exists(
+      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input, Ssa::PhiNode phi
+    |
+      guardChecks(g,
+        def.getARead().asIndirectOperand(indirectionIndex).getDef().getConvertedResultExpression(),
+        branch) and
+      guardControlsPhiInput(g, branch, def, input, phi) and
+      result = TSsaPhiInputNode(phi, input)
+    )
   }
 }
 
@@ -2728,6 +2861,14 @@ module BarrierGuard<guardChecksSig/3 guardChecks> {
  */
 signature predicate instructionGuardChecksSig(IRGuardCondition g, Instruction instr, boolean branch);
 
+private EdgeKind getConditionalEdge(boolean branch) {
+  branch = true and
+  result instanceof TrueEdge
+  or
+  branch = false and
+  result instanceof FalseEdge
+}
+
 /**
  * Provides a set of barrier nodes for a guard that validates an instruction.
  *
@@ -2736,12 +2877,20 @@ signature predicate instructionGuardChecksSig(IRGuardCondition g, Instruction in
  */
 module InstructionBarrierGuard<instructionGuardChecksSig/3 instructionGuardChecks> {
   /** Gets a node that is safely guarded by the given guard check. */
-  ExprNode getABarrierNode() {
+  Node getABarrierNode() {
     exists(IRGuardCondition g, ValueNumber value, boolean edge, Operand use |
       instructionGuardChecks(g, value.getAnInstruction(), edge) and
       use = value.getAnInstruction().getAUse() and
       result.asOperand() = use and
-      g.controls(use.getDef().getBlock(), edge)
+      g.controls(result.getBasicBlock(), edge)
+    )
+    or
+    exists(
+      IRGuardCondition g, boolean branch, Ssa::DefinitionExt def, IRBlock input, Ssa::PhiNode phi
+    |
+      instructionGuardChecks(g, def.getARead().asOperand().getDef(), branch) and
+      guardControlsPhiInput(g, branch, def, input, phi) and
+      result = TSsaPhiInputNode(phi, input)
     )
   }
 }

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/ProductFlow.qll

@@ -546,7 +546,7 @@ module ProductFlow {
       Flow1::PathGraph::edges(pred1, succ1, _, _) and
       exists(ReturnKindExt returnKind |
         succ1.getNode() = returnKind.getAnOutNode(call) and
-        pred1.getNode().(ReturnNodeExt).getKind() = returnKind
+        paramReturnNode(_, pred1.asParameterReturnNode(), _, returnKind)
       )
     }
 
@@ -574,7 +574,7 @@ module ProductFlow {
       Flow2::PathGraph::edges(pred2, succ2, _, _) and
       exists(ReturnKindExt returnKind |
         succ2.getNode() = returnKind.getAnOutNode(call) and
-        pred2.getNode().(ReturnNodeExt).getKind() = returnKind
+        paramReturnNode(_, pred2.asParameterReturnNode(), _, returnKind)
       )
     }
 

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

@@ -246,14 +246,6 @@ private module IteratorIndirections {
       baseType = super.getValueType()
     }
 
-    override predicate isAdditionalDereference(Instruction deref, Operand address) {
-      exists(CallInstruction call |
-        operandForFullyConvertedCall(getAUse(deref), call) and
-        this = call.getStaticCallTarget().getClassAndName("operator*") and
-        address = call.getThisArgumentOperand()
-      )
-    }
-
     override predicate isAdditionalWrite(Node0Impl value, Operand address, boolean certain) {
       exists(CallInstruction call | call.getArgumentOperand(0) = value.asOperand() |
         this = call.getStaticCallTarget().getClassAndName("operator=") and
@@ -262,16 +254,6 @@ private module IteratorIndirections {
       )
     }
 
-    override predicate isAdditionalTaintStep(Node node1, Node node2) {
-      exists(CallInstruction call |
-        // Taint through `operator+=` and `operator-=` on iterators.
-        call.getStaticCallTarget() instanceof Iterator::IteratorAssignArithmeticOperator and
-        node2.(IndirectArgumentOutNode).getPreUpdateNode() = node1 and
-        node1.(IndirectOperand).hasOperandAndIndirectionIndex(call.getArgumentOperand(0), _) and
-        node1.getType().getUnspecifiedType() = this
-      )
-    }
-
     override predicate isAdditionalConversionFlow(Operand opFrom, Instruction instrTo) {
       // This is a bit annoying: Consider the following snippet:
       // ```
@@ -589,230 +571,6 @@ private class BaseCallInstruction extends BaseSourceVariableInstruction, CallIns
 
 cached
 private module Cached {
-  private import semmle.code.cpp.models.interfaces.Iterator as Interfaces
-  private import semmle.code.cpp.models.implementations.Iterator as Iterator
-  private import semmle.code.cpp.models.interfaces.FunctionInputsAndOutputs as IO
-
-  /**
-   * Holds if `next` is a instruction with a memory result that potentially
-   * updates the memory produced by `prev`.
-   */
-  private predicate memorySucc(Instruction prev, Instruction next) {
-    prev = next.(ChiInstruction).getTotal()
-    or
-    // Phi inputs can be inexact.
-    prev = next.(PhiInstruction).getAnInputOperand().getAnyDef()
-    or
-    prev = next.(CopyInstruction).getSourceValue()
-    or
-    exists(ReadSideEffectInstruction read |
-      next = read.getPrimaryInstruction() and
-      isAdditionalConversionFlow(_, next) and
-      prev = read.getSideEffectOperand().getAnyDef()
-    )
-  }
-
-  /**
-   * Holds if `iteratorDerefAddress` is an address of an iterator dereference (i.e., `*it`)
-   * that is used for a write operation that writes the value `value`. The `memory` instruction
-   * represents the memory that the IR's SSA analysis determined was read by the call to `operator*`.
-   *
-   * The `numberOfLoads` integer represents the number of dereferences this write corresponds to
-   * on the underlying container that produced the iterator.
-   */
-  private predicate isChiAfterIteratorDef(
-    Instruction memory, Operand iteratorDerefAddress, Node0Impl value, int numberOfLoads
-  ) {
-    exists(
-      BaseSourceVariableInstruction iteratorBase, ReadSideEffectInstruction read,
-      Operand iteratorAddress
-    |
-      numberOfLoads >= 0 and
-      isDef(_, value, iteratorDerefAddress, iteratorBase, numberOfLoads + 2, 0) and
-      isUse(_, iteratorAddress, iteratorBase, numberOfLoads + 1, 0) and
-      iteratorBase.getResultType() instanceof Interfaces::Iterator and
-      isDereference(iteratorAddress.getDef(), read.getArgumentDef().getAUse(), _) and
-      memory = read.getSideEffectOperand().getAnyDef()
-    )
-  }
-
-  private predicate isSource(Instruction instr, Operand iteratorAddress, int numberOfLoads) {
-    getAUse(instr) = iteratorAddress and
-    exists(BaseSourceVariableInstruction iteratorBase |
-      iteratorBase.getResultType() instanceof Interfaces::Iterator and
-      not iteratorBase.getResultType() instanceof Cpp::PointerType and
-      isUse(_, iteratorAddress, iteratorBase, numberOfLoads - 1, 0)
-    )
-  }
-
-  private predicate isSink(Instruction instr, CallInstruction call) {
-    getAUse(instr).(ArgumentOperand).getCall() = call and
-    // Only include operations that may modify the object that the iterator points to.
-    // The following is a non-exhaustive list of things that may modify the value of the
-    // iterator, but never the value of what the iterator points to.
-    // The more things we can exclude here, the faster the small dataflow-like analysis
-    // done by `convertsIntoArgument` will converge.
-    not exists(Function f | f = call.getStaticCallTarget() |
-      f instanceof Iterator::IteratorCrementOperator or
-      f instanceof Iterator::IteratorBinaryArithmeticOperator or
-      f instanceof Iterator::IteratorAssignArithmeticOperator or
-      f instanceof Iterator::IteratorCrementMemberOperator or
-      f instanceof Iterator::IteratorBinaryArithmeticMemberOperator or
-      f instanceof Iterator::IteratorAssignArithmeticMemberOperator or
-      f instanceof Iterator::IteratorAssignmentMemberOperator
-    )
-  }
-
-  private predicate convertsIntoArgumentFwd(Instruction instr) {
-    isSource(instr, _, _)
-    or
-    exists(Instruction prev | convertsIntoArgumentFwd(prev) |
-      conversionFlow(unique( | | getAUse(prev)), instr, false, _)
-    )
-  }
-
-  private predicate convertsIntoArgumentRev(Instruction instr) {
-    convertsIntoArgumentFwd(instr) and
-    (
-      isSink(instr, _)
-      or
-      exists(Instruction next | convertsIntoArgumentRev(next) |
-        conversionFlow(unique( | | getAUse(instr)), next, false, _)
-      )
-    )
-  }
-
-  private predicate convertsIntoArgument(
-    Operand iteratorAddress, CallInstruction call, int numberOfLoads
-  ) {
-    exists(Instruction iteratorAddressDef |
-      isSource(iteratorAddressDef, iteratorAddress, numberOfLoads) and
-      isSink(iteratorAddressDef, call) and
-      convertsIntoArgumentRev(pragma[only_bind_into](iteratorAddressDef))
-    )
-  }
-
-  private predicate isChiAfterIteratorArgument(
-    Instruction memory, Operand iteratorAddress, int numberOfLoads
-  ) {
-    // Ideally, `iteratorAddress` would be an `ArgumentOperand`, but there might be
-    // various conversions applied to it before it becomes an argument.
-    // So we do a small amount of flow to find the call that the iterator is passed to.
-    exists(CallInstruction call | convertsIntoArgument(iteratorAddress, call, numberOfLoads) |
-      exists(ReadSideEffectInstruction read |
-        read.getPrimaryInstruction() = call and
-        read.getSideEffectOperand().getAnyDef() = memory
-      )
-      or
-      exists(LoadInstruction load |
-        iteratorAddress.getDef() = load and
-        memory = load.getSourceValueOperand().getAnyDef()
-      )
-    )
-  }
-
-  /**
-   * Holds if `iterator` is a `StoreInstruction` that stores the result of some function
-   * returning an iterator into an address computed started at `containerBase`.
-   *
-   * For example, given a declaration like `std::vector<int>::iterator it = v.begin()`,
-   * the `iterator` will be the `StoreInstruction` generated by the write to `it`, and
-   * `containerBase` will be the address of `v`.
-   */
-  private predicate isChiAfterBegin(
-    BaseSourceVariableInstruction containerBase, StoreInstruction iterator
-  ) {
-    exists(
-      CallInstruction getIterator, Iterator::GetIteratorFunction getIteratorFunction,
-      IO::FunctionInput input, int i
-    |
-      getIterator = iterator.getSourceValue() and
-      getIteratorFunction = getIterator.getStaticCallTarget() and
-      getIteratorFunction.getsIterator(input, _) and
-      isDef(_, any(Node0Impl n | n.asInstruction() = iterator), _, _, 1, 0) and
-      input.isParameterDerefOrQualifierObject(i) and
-      isUse(_, getIterator.getArgumentOperand(i), containerBase, 0, 0)
-    )
-  }
-
-  /**
-   * Holds if `iteratorAddress` is an address of an iterator that is used for
-   * a read operation. The `memory` instruction represents the memory that
-   * the IR's SSA analysis determined was read by the call to `operator*`.
-   *
-   * Finally, the `numberOfLoads` integer represents the number of dereferences
-   * this read corresponds to on the underlying container that produced the iterator.
-   */
-  private predicate isChiBeforeIteratorUse(
-    Operand iteratorAddress, Instruction memory, int numberOfLoads
-  ) {
-    exists(
-      BaseSourceVariableInstruction iteratorBase, LoadInstruction load,
-      ReadSideEffectInstruction read, Operand iteratorDerefAddress
-    |
-      numberOfLoads >= 0 and
-      isUse(_, iteratorAddress, iteratorBase, numberOfLoads + 1, 0) and
-      isUse(_, iteratorDerefAddress, iteratorBase, numberOfLoads + 2, 0) and
-      iteratorBase.getResultType() instanceof Interfaces::Iterator and
-      load.getSourceAddressOperand() = iteratorDerefAddress and
-      read.getPrimaryInstruction() = load.getSourceAddress() and
-      memory = read.getSideEffectOperand().getAnyDef()
-    )
-  }
-
-  /**
-   * Holds if `iteratorDerefAddress` is an address of an iterator dereference (i.e., `*it`)
-   * that is used for a write operation that writes the value `value` to a container that
-   * created the iterator. `container` represents the base of the address of the container
-   * that was used to create the iterator.
-   */
-  cached
-  predicate isIteratorDef(
-    BaseSourceVariableInstruction container, Operand iteratorDerefAddress, Node0Impl value,
-    int numberOfLoads, int indirectionIndex
-  ) {
-    exists(Instruction memory, Instruction begin, int upper, int ind |
-      isChiAfterIteratorDef(memory, iteratorDerefAddress, value, numberOfLoads) and
-      memorySucc*(begin, memory) and
-      isChiAfterBegin(container, begin) and
-      upper = countIndirectionsForCppType(getResultLanguageType(container)) and
-      ind = numberOfLoads + [1 .. upper] and
-      indirectionIndex = ind - (numberOfLoads + 1)
-    )
-  }
-
-  /**
-   * Holds if `iteratorAddress` is an address of an iterator that is used for a
-   * read operation to read a value from a container that created the iterator.
-   * `container` represents the base of the address of the container that was used
-   * to create the iterator.
-   */
-  cached
-  predicate isIteratorUse(
-    BaseSourceVariableInstruction container, Operand iteratorAddress, int numberOfLoads,
-    int indirectionIndex
-  ) {
-    // Direct use
-    exists(Instruction begin, Instruction memory, int upper, int ind |
-      isChiBeforeIteratorUse(iteratorAddress, memory, numberOfLoads) and
-      memorySucc*(begin, memory) and
-      isChiAfterBegin(container, begin) and
-      upper = countIndirectionsForCppType(getResultLanguageType(container)) and
-      ind = numberOfLoads + [1 .. upper] and
-      indirectionIndex = ind - (numberOfLoads + 1)
-    )
-    or
-    // Use through function output
-    exists(Instruction memory, Instruction begin, int upper, int ind |
-      isChiAfterIteratorArgument(memory, iteratorAddress, numberOfLoads) and
-      memorySucc*(begin, memory) and
-      isChiAfterBegin(container, begin) and
-      upper = countIndirectionsForCppType(getResultLanguageType(container)) and
-      ind = numberOfLoads + [1 .. upper] and
-      indirectionIndex = ind - (numberOfLoads - 1)
-    )
-  }
-
   /** Holds if `op` is the only use of its defining instruction, and that op is used in a conversation */
   private predicate isConversion(Operand op) {
     exists(Instruction def, Operand use |

cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/IRVariable.qll

@@ -17,18 +17,11 @@ private import Imports::IRType
  * The variable may be a user-declared variable (`IRUserVariable`) or a temporary variable generated
  * by the AST-to-IR translation (`IRTempVariable`).
  */
-class IRVariable extends TIRVariable {
+abstract private class AbstractIRVariable extends TIRVariable {
   Language::Declaration func;
 
-  IRVariable() {
-    this = TIRUserVariable(_, _, func) or
-    this = TIRTempVariable(func, _, _, _) or
-    this = TIRStringLiteral(func, _, _, _) or
-    this = TIRDynamicInitializationFlag(func, _, _)
-  }
-
   /** Gets a textual representation of this element. */
-  string toString() { none() }
+  abstract string toString();
 
   /**
    * Holds if this variable's value cannot be changed within a function. Currently used for string
@@ -49,13 +42,13 @@ class IRVariable extends TIRVariable {
   /**
    * Gets the type of the variable.
    */
-  Language::LanguageType getLanguageType() { none() }
+  abstract Language::LanguageType getLanguageType();
 
   /**
    * Gets the AST node that declared this variable, or that introduced this
    * variable as part of the AST-to-IR translation.
    */
-  Language::AST getAst() { none() }
+  abstract Language::AST getAst();
 
   /** DEPRECATED: Alias for getAst */
   deprecated Language::AST getAST() { result = this.getAst() }
@@ -64,7 +57,7 @@ class IRVariable extends TIRVariable {
    * Gets an identifier string for the variable. This identifier is unique
    * within the function.
    */
-  string getUniqueId() { none() }
+  abstract string getUniqueId();
 
   /**
    * Gets the source location of this variable.
@@ -74,7 +67,7 @@ class IRVariable extends TIRVariable {
   /**
    * Gets the IR for the function that references this variable.
    */
-  final IRFunction getEnclosingIRFunction() { result.getFunction() = func }
+  final IRFunction getEnclosingIRFunction() { result.getFunction() = this.getEnclosingFunction() }
 
   /**
    * Gets the function that references this variable.
@@ -82,10 +75,18 @@ class IRVariable extends TIRVariable {
   final Language::Declaration getEnclosingFunction() { result = func }
 }
 
+/**
+ * A variable referenced by the IR for a function.
+ *
+ * The variable may be a user-declared variable (`IRUserVariable`) or a temporary variable generated
+ * by the AST-to-IR translation (`IRTempVariable`).
+ */
+final class IRVariable = AbstractIRVariable;
+
 /**
  * A user-declared variable referenced by the IR for a function.
  */
-class IRUserVariable extends IRVariable, TIRUserVariable {
+class IRUserVariable extends AbstractIRVariable, TIRUserVariable {
   Language::Variable var;
   Language::LanguageType type;
 
@@ -114,26 +115,29 @@ class IRUserVariable extends IRVariable, TIRUserVariable {
  * A variable (user-declared or temporary) that is allocated on the stack. This includes all
  * parameters, non-static local variables, and temporary variables.
  */
-class IRAutomaticVariable extends IRVariable {
-  IRAutomaticVariable() {
-    exists(Language::Variable var |
-      this = TIRUserVariable(var, _, func) and
-      Language::isVariableAutomatic(var)
-    )
-    or
-    this = TIRTempVariable(func, _, _, _)
-  }
+abstract private class AbstractIRAutomaticVariable extends AbstractIRVariable { }
+
+/**
+ * A variable (user-declared or temporary) that is allocated on the stack. This includes all
+ * parameters, non-static local variables, and temporary variables.
+ */
+final class IRAutomaticVariable = AbstractIRAutomaticVariable;
+
+/**
+ * A user-declared variable that is allocated on the stack. This includes all parameters and
+ * non-static local variables.
+ */
+private class AbstractIRAutomaticUserVariable extends IRUserVariable, AbstractIRAutomaticVariable {
+  override Language::AutomaticVariable var;
+
+  final override Language::AutomaticVariable getVariable() { result = var }
 }
 
 /**
  * A user-declared variable that is allocated on the stack. This includes all parameters and
  * non-static local variables.
  */
-class IRAutomaticUserVariable extends IRUserVariable, IRAutomaticVariable {
-  override Language::AutomaticVariable var;
-
-  final override Language::AutomaticVariable getVariable() { result = var }
-}
+final class IRAutomaticUserVariable = AbstractIRAutomaticUserVariable;
 
 /**
  * A user-declared variable that is not allocated on the stack. This includes all global variables,
@@ -151,16 +155,10 @@ class IRStaticUserVariable extends IRUserVariable {
  * A variable that is not user-declared. This includes temporary variables generated as part of IR
  * construction, as well as string literals.
  */
-class IRGeneratedVariable extends IRVariable {
+abstract private class AbstractIRGeneratedVariable extends AbstractIRVariable {
   Language::AST ast;
   Language::LanguageType type;
 
-  IRGeneratedVariable() {
-    this = TIRTempVariable(func, ast, _, type) or
-    this = TIRStringLiteral(func, ast, type, _) or
-    this = TIRDynamicInitializationFlag(func, ast, type)
-  }
-
   final override Language::LanguageType getLanguageType() { result = type }
 
   final override Language::AST getAst() { result = ast }
@@ -196,12 +194,20 @@ class IRGeneratedVariable extends IRVariable {
   string getBaseString() { none() }
 }
 
+/**
+ * A variable that is not user-declared. This includes temporary variables generated as part of IR
+ * construction, as well as string literals.
+ */
+final class IRGeneratedVariable = AbstractIRGeneratedVariable;
+
 /**
  * A temporary variable introduced by IR construction. The most common examples are the variable
  * generated to hold the return value of a function, or the variable generated to hold the result of
  * a condition operator (`a ? b : c`).
  */
-class IRTempVariable extends IRGeneratedVariable, IRAutomaticVariable, TIRTempVariable {
+class IRTempVariable extends AbstractIRGeneratedVariable, AbstractIRAutomaticVariable,
+  TIRTempVariable
+{
   TempVariableTag tag;
 
   IRTempVariable() { this = TIRTempVariable(func, ast, tag, type) }
@@ -241,7 +247,7 @@ class IRThrowVariable extends IRTempVariable {
  * A temporary variable generated to hold the contents of all arguments passed to the `...` of a
  * function that accepts a variable number of arguments.
  */
-class IREllipsisVariable extends IRTempVariable, IRParameter {
+class IREllipsisVariable extends IRTempVariable, AbstractIRParameter {
   IREllipsisVariable() { tag = EllipsisTempVar() }
 
   final override string toString() { result = "#ellipsis" }
@@ -252,7 +258,7 @@ class IREllipsisVariable extends IRTempVariable, IRParameter {
 /**
  * A temporary variable generated to hold the `this` pointer.
  */
-class IRThisVariable extends IRTempVariable, IRParameter {
+class IRThisVariable extends IRTempVariable, AbstractIRParameter {
   IRThisVariable() { tag = ThisTempVar() }
 
   final override string toString() { result = "#this" }
@@ -264,7 +270,7 @@ class IRThisVariable extends IRTempVariable, IRParameter {
  * A variable generated to represent the contents of a string literal. This variable acts much like
  * a read-only global variable.
  */
-class IRStringLiteral extends IRGeneratedVariable, TIRStringLiteral {
+class IRStringLiteral extends AbstractIRGeneratedVariable, TIRStringLiteral {
   Language::StringLiteral literal;
 
   IRStringLiteral() { this = TIRStringLiteral(func, ast, type, literal) }
@@ -288,7 +294,7 @@ class IRStringLiteral extends IRGeneratedVariable, TIRStringLiteral {
  * used to model the runtime initialization of static local variables in C++, as well as static
  * fields in C#.
  */
-class IRDynamicInitializationFlag extends IRGeneratedVariable, TIRDynamicInitializationFlag {
+class IRDynamicInitializationFlag extends AbstractIRGeneratedVariable, TIRDynamicInitializationFlag {
   Language::Variable var;
 
   IRDynamicInitializationFlag() {
@@ -314,24 +320,24 @@ class IRDynamicInitializationFlag extends IRGeneratedVariable, TIRDynamicInitial
  * An IR variable which acts like a function parameter, including positional parameters and the
  * temporary variables generated for `this` and ellipsis parameters.
  */
-class IRParameter extends IRAutomaticVariable {
-  IRParameter() {
-    this.(IRAutomaticUserVariable).getVariable() instanceof Language::Parameter
-    or
-    this = TIRTempVariable(_, _, ThisTempVar(), _)
-    or
-    this = TIRTempVariable(_, _, EllipsisTempVar(), _)
-  }
-
+abstract private class AbstractIRParameter extends AbstractIRAutomaticVariable {
   /**
    * Gets the zero-based index of this parameter. The `this` parameter has index -1.
    */
   int getIndex() { none() }
 }
 
+/**
+ * An IR variable which acts like a function parameter, including positional parameters and the
+ * temporary variables generated for `this` and ellipsis parameters.
+ */
+final class IRParameter = AbstractIRParameter;
+
 /**
  * An IR variable representing a positional parameter.
  */
-class IRPositionalParameter extends IRParameter, IRAutomaticUserVariable {
+class IRPositionalParameter extends AbstractIRParameter, AbstractIRAutomaticUserVariable {
+  IRPositionalParameter() { this.getVariable() instanceof Language::Parameter }
+
   final override int getIndex() { result = this.getVariable().(Language::Parameter).getIndex() }
 }

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/IRVariable.qll

@@ -17,18 +17,11 @@ private import Imports::IRType
  * The variable may be a user-declared variable (`IRUserVariable`) or a temporary variable generated
  * by the AST-to-IR translation (`IRTempVariable`).
  */
-class IRVariable extends TIRVariable {
+abstract private class AbstractIRVariable extends TIRVariable {
   Language::Declaration func;
 
-  IRVariable() {
-    this = TIRUserVariable(_, _, func) or
-    this = TIRTempVariable(func, _, _, _) or
-    this = TIRStringLiteral(func, _, _, _) or
-    this = TIRDynamicInitializationFlag(func, _, _)
-  }
-
   /** Gets a textual representation of this element. */
-  string toString() { none() }
+  abstract string toString();
 
   /**
    * Holds if this variable's value cannot be changed within a function. Currently used for string
@@ -49,13 +42,13 @@ class IRVariable extends TIRVariable {
   /**
    * Gets the type of the variable.
    */
-  Language::LanguageType getLanguageType() { none() }
+  abstract Language::LanguageType getLanguageType();
 
   /**
    * Gets the AST node that declared this variable, or that introduced this
    * variable as part of the AST-to-IR translation.
    */
-  Language::AST getAst() { none() }
+  abstract Language::AST getAst();
 
   /** DEPRECATED: Alias for getAst */
   deprecated Language::AST getAST() { result = this.getAst() }
@@ -64,7 +57,7 @@ class IRVariable extends TIRVariable {
    * Gets an identifier string for the variable. This identifier is unique
    * within the function.
    */
-  string getUniqueId() { none() }
+  abstract string getUniqueId();
 
   /**
    * Gets the source location of this variable.
@@ -74,7 +67,7 @@ class IRVariable extends TIRVariable {
   /**
    * Gets the IR for the function that references this variable.
    */
-  final IRFunction getEnclosingIRFunction() { result.getFunction() = func }
+  final IRFunction getEnclosingIRFunction() { result.getFunction() = this.getEnclosingFunction() }
 
   /**
    * Gets the function that references this variable.
@@ -82,10 +75,18 @@ class IRVariable extends TIRVariable {
   final Language::Declaration getEnclosingFunction() { result = func }
 }
 
+/**
+ * A variable referenced by the IR for a function.
+ *
+ * The variable may be a user-declared variable (`IRUserVariable`) or a temporary variable generated
+ * by the AST-to-IR translation (`IRTempVariable`).
+ */
+final class IRVariable = AbstractIRVariable;
+
 /**
  * A user-declared variable referenced by the IR for a function.
  */
-class IRUserVariable extends IRVariable, TIRUserVariable {
+class IRUserVariable extends AbstractIRVariable, TIRUserVariable {
   Language::Variable var;
   Language::LanguageType type;
 
@@ -114,26 +115,29 @@ class IRUserVariable extends IRVariable, TIRUserVariable {
  * A variable (user-declared or temporary) that is allocated on the stack. This includes all
  * parameters, non-static local variables, and temporary variables.
  */
-class IRAutomaticVariable extends IRVariable {
-  IRAutomaticVariable() {
-    exists(Language::Variable var |
-      this = TIRUserVariable(var, _, func) and
-      Language::isVariableAutomatic(var)
-    )
-    or
-    this = TIRTempVariable(func, _, _, _)
-  }
+abstract private class AbstractIRAutomaticVariable extends AbstractIRVariable { }
+
+/**
+ * A variable (user-declared or temporary) that is allocated on the stack. This includes all
+ * parameters, non-static local variables, and temporary variables.
+ */
+final class IRAutomaticVariable = AbstractIRAutomaticVariable;
+
+/**
+ * A user-declared variable that is allocated on the stack. This includes all parameters and
+ * non-static local variables.
+ */
+private class AbstractIRAutomaticUserVariable extends IRUserVariable, AbstractIRAutomaticVariable {
+  override Language::AutomaticVariable var;
+
+  final override Language::AutomaticVariable getVariable() { result = var }
 }
 
 /**
  * A user-declared variable that is allocated on the stack. This includes all parameters and
  * non-static local variables.
  */
-class IRAutomaticUserVariable extends IRUserVariable, IRAutomaticVariable {
-  override Language::AutomaticVariable var;
-
-  final override Language::AutomaticVariable getVariable() { result = var }
-}
+final class IRAutomaticUserVariable = AbstractIRAutomaticUserVariable;
 
 /**
  * A user-declared variable that is not allocated on the stack. This includes all global variables,
@@ -151,16 +155,10 @@ class IRStaticUserVariable extends IRUserVariable {
  * A variable that is not user-declared. This includes temporary variables generated as part of IR
  * construction, as well as string literals.
  */
-class IRGeneratedVariable extends IRVariable {
+abstract private class AbstractIRGeneratedVariable extends AbstractIRVariable {
   Language::AST ast;
   Language::LanguageType type;
 
-  IRGeneratedVariable() {
-    this = TIRTempVariable(func, ast, _, type) or
-    this = TIRStringLiteral(func, ast, type, _) or
-    this = TIRDynamicInitializationFlag(func, ast, type)
-  }
-
   final override Language::LanguageType getLanguageType() { result = type }
 
   final override Language::AST getAst() { result = ast }
@@ -196,12 +194,20 @@ class IRGeneratedVariable extends IRVariable {
   string getBaseString() { none() }
 }
 
+/**
+ * A variable that is not user-declared. This includes temporary variables generated as part of IR
+ * construction, as well as string literals.
+ */
+final class IRGeneratedVariable = AbstractIRGeneratedVariable;
+
 /**
  * A temporary variable introduced by IR construction. The most common examples are the variable
  * generated to hold the return value of a function, or the variable generated to hold the result of
  * a condition operator (`a ? b : c`).
  */
-class IRTempVariable extends IRGeneratedVariable, IRAutomaticVariable, TIRTempVariable {
+class IRTempVariable extends AbstractIRGeneratedVariable, AbstractIRAutomaticVariable,
+  TIRTempVariable
+{
   TempVariableTag tag;
 
   IRTempVariable() { this = TIRTempVariable(func, ast, tag, type) }
@@ -241,7 +247,7 @@ class IRThrowVariable extends IRTempVariable {
  * A temporary variable generated to hold the contents of all arguments passed to the `...` of a
  * function that accepts a variable number of arguments.
  */
-class IREllipsisVariable extends IRTempVariable, IRParameter {
+class IREllipsisVariable extends IRTempVariable, AbstractIRParameter {
   IREllipsisVariable() { tag = EllipsisTempVar() }
 
   final override string toString() { result = "#ellipsis" }
@@ -252,7 +258,7 @@ class IREllipsisVariable extends IRTempVariable, IRParameter {
 /**
  * A temporary variable generated to hold the `this` pointer.
  */
-class IRThisVariable extends IRTempVariable, IRParameter {
+class IRThisVariable extends IRTempVariable, AbstractIRParameter {
   IRThisVariable() { tag = ThisTempVar() }
 
   final override string toString() { result = "#this" }
@@ -264,7 +270,7 @@ class IRThisVariable extends IRTempVariable, IRParameter {
  * A variable generated to represent the contents of a string literal. This variable acts much like
  * a read-only global variable.
  */
-class IRStringLiteral extends IRGeneratedVariable, TIRStringLiteral {
+class IRStringLiteral extends AbstractIRGeneratedVariable, TIRStringLiteral {
   Language::StringLiteral literal;
 
   IRStringLiteral() { this = TIRStringLiteral(func, ast, type, literal) }
@@ -288,7 +294,7 @@ class IRStringLiteral extends IRGeneratedVariable, TIRStringLiteral {
  * used to model the runtime initialization of static local variables in C++, as well as static
  * fields in C#.
  */
-class IRDynamicInitializationFlag extends IRGeneratedVariable, TIRDynamicInitializationFlag {
+class IRDynamicInitializationFlag extends AbstractIRGeneratedVariable, TIRDynamicInitializationFlag {
   Language::Variable var;
 
   IRDynamicInitializationFlag() {
@@ -314,24 +320,24 @@ class IRDynamicInitializationFlag extends IRGeneratedVariable, TIRDynamicInitial
  * An IR variable which acts like a function parameter, including positional parameters and the
  * temporary variables generated for `this` and ellipsis parameters.
  */
-class IRParameter extends IRAutomaticVariable {
-  IRParameter() {
-    this.(IRAutomaticUserVariable).getVariable() instanceof Language::Parameter
-    or
-    this = TIRTempVariable(_, _, ThisTempVar(), _)
-    or
-    this = TIRTempVariable(_, _, EllipsisTempVar(), _)
-  }
-
+abstract private class AbstractIRParameter extends AbstractIRAutomaticVariable {
   /**
    * Gets the zero-based index of this parameter. The `this` parameter has index -1.
    */
   int getIndex() { none() }
 }
 
+/**
+ * An IR variable which acts like a function parameter, including positional parameters and the
+ * temporary variables generated for `this` and ellipsis parameters.
+ */
+final class IRParameter = AbstractIRParameter;
+
 /**
  * An IR variable representing a positional parameter.
  */
-class IRPositionalParameter extends IRParameter, IRAutomaticUserVariable {
+class IRPositionalParameter extends AbstractIRParameter, AbstractIRAutomaticUserVariable {
+  IRPositionalParameter() { this.getVariable() instanceof Language::Parameter }
+
   final override int getIndex() { result = this.getVariable().(Language::Parameter).getIndex() }
 }

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedElement.qll

@@ -830,6 +830,12 @@ newtype TTranslatedElement =
       not ignoreExpr(dc)
     )
   } or
+  // The set of destructors to invoke after a handler for a `try` statement. These
+  // need to be special cased because the destructors need to run following an
+  // `ExceptionEdge`, but not following a `GotoEdge` edge.
+  TTranslatedDestructorsAfterHandler(Handler handler) {
+    exists(handler.getAnImplicitDestructorCall())
+  } or
   // A precise side effect of an argument to a `Call`
   TTranslatedArgumentExprSideEffect(Call call, Expr expr, int n, SideEffectOpcode opcode) {
     not ignoreExpr(expr) and

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedExpr.qll

@@ -1844,9 +1844,6 @@ class TranslatedAssignExpr extends TranslatedNonConstantExpr {
     child = this.getRightOperand() and
     result = this.getLeftOperand().getFirstInstruction(kind)
     or
-    child = this.getRightOperand() and
-    result = this.getLeftOperand().getFirstInstruction(kind)
-    or
     kind instanceof GotoEdge and
     child = this.getLeftOperand() and
     result = this.getInstruction(AssignmentStoreTag())
@@ -3211,9 +3208,20 @@ class TranslatedBuiltInOperation extends TranslatedNonConstantExpr {
 
   final override Instruction getResult() { result = this.getInstruction(OnlyInstructionTag()) }
 
+  /**
+   * Gets the rnk'th (0-indexed) child for which a `TranslatedElement` exists.
+   *
+   * We use this predicate to filter out `TypeName` expressions that sometimes
+   * occur in builtin operations since the IR doesn't have an instruction to
+   * represent a reference to a type.
+   */
+  private TranslatedElement getRankedChild(int rnk) {
+    result = rank[rnk + 1](int id, TranslatedElement te | te = this.getChild(id) | te order by id)
+  }
+
   final override Instruction getFirstInstruction(EdgeKind kind) {
-    if exists(this.getChild(0))
-    then result = this.getChild(0).getFirstInstruction(kind)
+    if exists(this.getRankedChild(0))
+    then result = this.getRankedChild(0).getFirstInstruction(kind)
     else (
       kind instanceof GotoEdge and result = this.getInstruction(OnlyInstructionTag())
     )
@@ -3233,11 +3241,11 @@ class TranslatedBuiltInOperation extends TranslatedNonConstantExpr {
   }
 
   final override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
-    exists(int id | child = this.getChild(id) |
-      result = this.getChild(id + 1).getFirstInstruction(kind)
+    exists(int id | child = this.getRankedChild(id) |
+      result = this.getRankedChild(id + 1).getFirstInstruction(kind)
       or
       kind instanceof GotoEdge and
-      not exists(this.getChild(id + 1)) and
+      not exists(this.getRankedChild(id + 1)) and
       result = this.getInstruction(OnlyInstructionTag())
     )
   }
@@ -3252,7 +3260,7 @@ class TranslatedBuiltInOperation extends TranslatedNonConstantExpr {
     tag = OnlyInstructionTag() and
     exists(int index |
       operandTag = positionalArgumentOperand(index) and
-      result = this.getChild(index).(TranslatedExpr).getResult()
+      result = this.getRankedChild(index).(TranslatedExpr).getResult()
     )
   }
 

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedStmt.qll

@@ -777,6 +777,72 @@ abstract class TranslatedHandler extends TranslatedStmt {
   TranslatedStmt getBlock() { result = getTranslatedStmt(stmt.getBlock()) }
 }
 
+/**
+ * The IR translation of the destructor calls of the parent `TranslatedCatchByTypeHandler`.
+ *
+ * This object does not itself generate the destructor calls. Instead, its
+ * children provide the actual calls.
+ */
+class TranslatedDestructorsAfterHandler extends TranslatedElement,
+  TTranslatedDestructorsAfterHandler
+{
+  Handler handler;
+
+  TranslatedDestructorsAfterHandler() { this = TTranslatedDestructorsAfterHandler(handler) }
+
+  override string toString() { result = "Destructor calls after handler: " + handler }
+
+  private TranslatedCall getTranslatedImplicitDestructorCall(int id) {
+    result.getExpr() = handler.getImplicitDestructorCall(id)
+  }
+
+  override Instruction getFirstInstruction(EdgeKind kind) {
+    result = this.getChild(0).getFirstInstruction(kind)
+  }
+
+  override Handler getAst() { result = handler }
+
+  override Instruction getInstructionSuccessorInternal(InstructionTag tag, EdgeKind kind) { none() }
+
+  override TranslatedElement getChild(int id) {
+    result = this.getTranslatedImplicitDestructorCall(id)
+  }
+
+  override predicate handlesDestructorsExplicitly() { any() }
+
+  override Declaration getFunction() { result = handler.getEnclosingFunction() }
+
+  override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
+    exists(int id | child = this.getChild(id) |
+      // Transition to the next child, if any.
+      result = this.getChild(id + 1).getFirstInstruction(kind)
+      or
+      // And otherwise go to the next handler, if any.
+      not exists(this.getChild(id + 1)) and
+      result =
+        getTranslatedStmt(handler)
+            .getParent()
+            .(TranslatedTryStmt)
+            .getNextHandler(getTranslatedStmt(handler), kind)
+    )
+  }
+
+  override TranslatedElement getLastChild() {
+    result =
+      this.getTranslatedImplicitDestructorCall(max(int id |
+          exists(handler.getImplicitDestructorCall(id))
+        ))
+  }
+
+  override Instruction getALastInstructionInternal() {
+    result = this.getLastChild().getALastInstruction()
+  }
+
+  override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType resultType) {
+    none()
+  }
+}
+
 /**
  * The IR translation of a C++ `catch` block that catches an exception with a
  * specific type (e.g. `catch (const std::exception&)`).
@@ -790,10 +856,14 @@ class TranslatedCatchByTypeHandler extends TranslatedHandler {
     resultType = getVoidType()
   }
 
+  override predicate handlesDestructorsExplicitly() { any() }
+
   override TranslatedElement getChildInternal(int id) {
     result = super.getChildInternal(id)
     or
     id = 0 and result = this.getParameter()
+    or
+    id = 1 and result = this.getDestructors()
   }
 
   override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
@@ -810,7 +880,9 @@ class TranslatedCatchByTypeHandler extends TranslatedHandler {
       result = this.getParameter().getFirstInstruction(kind)
       or
       kind instanceof ExceptionEdge and
-      result = this.getParent().(TranslatedTryStmt).getNextHandler(this, any(GotoEdge edge))
+      if exists(this.getDestructors())
+      then result = this.getDestructors().getFirstInstruction(any(GotoEdge edge))
+      else result = this.getParent().(TranslatedTryStmt).getNextHandler(this, any(GotoEdge edge))
     )
   }
 
@@ -822,6 +894,8 @@ class TranslatedCatchByTypeHandler extends TranslatedHandler {
   private TranslatedParameter getParameter() {
     result = getTranslatedParameter(stmt.getParameter())
   }
+
+  private TranslatedDestructorsAfterHandler getDestructors() { result.getAst() = stmt }
 }
 
 /**
@@ -842,9 +916,7 @@ class TranslatedCatchAnyHandler extends TranslatedHandler {
   }
 }
 
-class TranslatedIfStmt extends TranslatedStmt, ConditionContext {
-  override IfStmt stmt;
-
+abstract class TranslatedIfLikeStmt extends TranslatedStmt, ConditionContext {
   override Instruction getFirstInstruction(EdgeKind kind) {
     if this.hasInitialization()
     then result = this.getInitialization().getFirstInstruction(kind)
@@ -857,6 +929,8 @@ class TranslatedIfStmt extends TranslatedStmt, ConditionContext {
 
   override TranslatedElement getLastChild() { result = this.getElse() or result = this.getThen() }
 
+  override predicate handlesDestructorsExplicitly() { any() }
+
   override TranslatedElement getChildInternal(int id) {
     id = 0 and result = this.getInitialization()
     or
@@ -867,25 +941,21 @@ class TranslatedIfStmt extends TranslatedStmt, ConditionContext {
     id = 3 and result = this.getElse()
   }
 
-  private predicate hasInitialization() { exists(stmt.getInitialization()) }
+  abstract predicate hasInitialization();
 
-  private TranslatedStmt getInitialization() {
-    result = getTranslatedStmt(stmt.getInitialization())
-  }
+  abstract TranslatedStmt getInitialization();
 
-  private TranslatedCondition getCondition() {
-    result = getTranslatedCondition(stmt.getCondition().getFullyConverted())
-  }
+  abstract TranslatedCondition getCondition();
 
   private Instruction getFirstConditionInstruction(EdgeKind kind) {
     result = this.getCondition().getFirstInstruction(kind)
   }
 
-  private TranslatedStmt getThen() { result = getTranslatedStmt(stmt.getThen()) }
+  abstract TranslatedStmt getThen();
 
-  private TranslatedStmt getElse() { result = getTranslatedStmt(stmt.getElse()) }
+  abstract TranslatedStmt getElse();
 
-  private predicate hasElse() { exists(stmt.getElse()) }
+  abstract predicate hasElse();
 
   override Instruction getInstructionSuccessorInternal(InstructionTag tag, EdgeKind kind) { none() }
 
@@ -898,7 +968,11 @@ class TranslatedIfStmt extends TranslatedStmt, ConditionContext {
     child = this.getCondition() and
     if this.hasElse()
     then result = this.getElse().getFirstInstruction(kind)
-    else result = this.getParent().getChildSuccessor(this, kind)
+    else (
+      if this.hasAnImplicitDestructorCall()
+      then result = this.getChild(this.getFirstDestructorCallIndex()).getFirstInstruction(kind)
+      else result = this.getParent().getChildSuccessor(this, kind)
+    )
   }
 
   override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
@@ -906,7 +980,24 @@ class TranslatedIfStmt extends TranslatedStmt, ConditionContext {
     result = this.getFirstConditionInstruction(kind)
     or
     (child = this.getThen() or child = this.getElse()) and
-    result = this.getParent().getChildSuccessor(this, kind)
+    (
+      if this.hasAnImplicitDestructorCall()
+      then result = this.getChild(this.getFirstDestructorCallIndex()).getFirstInstruction(kind)
+      else result = this.getParent().getChildSuccessor(this, kind)
+    )
+    or
+    exists(int destructorId |
+      destructorId >= this.getFirstDestructorCallIndex() and
+      child = this.getChild(destructorId) and
+      result = this.getChild(destructorId + 1).getFirstInstruction(kind)
+    )
+    or
+    exists(int lastDestructorIndex |
+      lastDestructorIndex =
+        max(int n | exists(this.getChild(n)) and n >= this.getFirstDestructorCallIndex()) and
+      child = this.getChild(lastDestructorIndex) and
+      result = this.getParent().getChildSuccessor(this, kind)
+    )
   }
 
   override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType resultType) {
@@ -914,76 +1005,44 @@ class TranslatedIfStmt extends TranslatedStmt, ConditionContext {
   }
 }
 
-class TranslatedConstExprIfStmt extends TranslatedStmt, ConditionContext {
-  override ConstexprIfStmt stmt;
+class TranslatedIfStmt extends TranslatedIfLikeStmt {
+  override IfStmt stmt;
 
-  override Instruction getFirstInstruction(EdgeKind kind) {
-    if this.hasInitialization()
-    then result = this.getInitialization().getFirstInstruction(kind)
-    else result = this.getFirstConditionInstruction(kind)
-  }
+  override predicate hasInitialization() { exists(stmt.getInitialization()) }
 
-  override TranslatedElement getChildInternal(int id) {
-    id = 0 and result = this.getInitialization()
-    or
-    id = 1 and result = this.getCondition()
-    or
-    id = 2 and result = this.getThen()
-    or
-    id = 3 and result = this.getElse()
-  }
-
-  private predicate hasInitialization() { exists(stmt.getInitialization()) }
-
-  private TranslatedStmt getInitialization() {
+  override TranslatedStmt getInitialization() {
     result = getTranslatedStmt(stmt.getInitialization())
   }
 
-  private TranslatedCondition getCondition() {
+  override TranslatedCondition getCondition() {
     result = getTranslatedCondition(stmt.getCondition().getFullyConverted())
   }
 
-  private Instruction getFirstConditionInstruction(EdgeKind kind) {
-    result = this.getCondition().getFirstInstruction(kind)
+  override TranslatedStmt getThen() { result = getTranslatedStmt(stmt.getThen()) }
+
+  override TranslatedStmt getElse() { result = getTranslatedStmt(stmt.getElse()) }
+
+  override predicate hasElse() { exists(stmt.getElse()) }
+}
+
+class TranslatedConstExprIfStmt extends TranslatedIfLikeStmt {
+  override ConstexprIfStmt stmt;
+
+  override predicate hasInitialization() { exists(stmt.getInitialization()) }
+
+  override TranslatedStmt getInitialization() {
+    result = getTranslatedStmt(stmt.getInitialization())
   }
 
-  private TranslatedStmt getThen() { result = getTranslatedStmt(stmt.getThen()) }
-
-  private TranslatedStmt getElse() { result = getTranslatedStmt(stmt.getElse()) }
-
-  private predicate hasElse() { exists(stmt.getElse()) }
-
-  override Instruction getInstructionSuccessorInternal(InstructionTag tag, EdgeKind kind) { none() }
-
-  override Instruction getChildTrueSuccessor(TranslatedCondition child, EdgeKind kind) {
-    child = this.getCondition() and
-    result = this.getThen().getFirstInstruction(kind)
+  override TranslatedCondition getCondition() {
+    result = getTranslatedCondition(stmt.getCondition().getFullyConverted())
   }
 
-  override Instruction getChildFalseSuccessor(TranslatedCondition child, EdgeKind kind) {
-    child = this.getCondition() and
-    if this.hasElse()
-    then result = this.getElse().getFirstInstruction(kind)
-    else result = this.getParent().getChildSuccessor(this, kind)
-  }
+  override TranslatedStmt getThen() { result = getTranslatedStmt(stmt.getThen()) }
 
-  override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
-    child = this.getInitialization() and
-    result = this.getFirstConditionInstruction(kind)
-    or
-    (child = this.getThen() or child = this.getElse()) and
-    result = this.getParent().getChildSuccessor(this, kind)
-  }
+  override TranslatedStmt getElse() { result = getTranslatedStmt(stmt.getElse()) }
 
-  override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType resultType) {
-    none()
-  }
-
-  override Instruction getALastInstructionInternal() {
-    result = this.getThen().getALastInstruction()
-    or
-    result = this.getElse().getALastInstruction()
-  }
+  override predicate hasElse() { exists(stmt.getElse()) }
 }
 
 abstract class TranslatedLoop extends TranslatedStmt, ConditionContext {
@@ -1163,6 +1222,8 @@ class TranslatedForStmt extends TranslatedLoop {
 class TranslatedRangeBasedForStmt extends TranslatedStmt, ConditionContext {
   override RangeBasedForStmt stmt;
 
+  override predicate handlesDestructorsExplicitly() { any() }
+
   override TranslatedElement getChildInternal(int id) {
     id = 0 and result = this.getInitialization()
     or
@@ -1216,6 +1277,19 @@ class TranslatedRangeBasedForStmt extends TranslatedStmt, ConditionContext {
     or
     child = this.getUpdate() and
     result = this.getCondition().getFirstInstruction(kind)
+    or
+    exists(int destructorId |
+      destructorId >= this.getFirstDestructorCallIndex() and
+      child = this.getChild(destructorId) and
+      result = this.getChild(destructorId + 1).getFirstInstruction(kind)
+    )
+    or
+    exists(int lastDestructorIndex |
+      lastDestructorIndex =
+        max(int n | exists(this.getChild(n)) and n >= this.getFirstDestructorCallIndex()) and
+      child = this.getChild(lastDestructorIndex) and
+      result = this.getParent().getChildSuccessor(this, kind)
+    )
   }
 
   override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType resultType) {
@@ -1231,7 +1305,9 @@ class TranslatedRangeBasedForStmt extends TranslatedStmt, ConditionContext {
 
   override Instruction getChildFalseSuccessor(TranslatedCondition child, EdgeKind kind) {
     child = this.getCondition() and
-    result = this.getParent().getChildSuccessor(this, kind)
+    if this.hasAnImplicitDestructorCall()
+    then result = this.getChild(this.getFirstDestructorCallIndex()).getFirstInstruction(kind)
+    else result = this.getParent().getChildSuccessor(this, kind)
   }
 
   private TranslatedDeclStmt getRangeVariableDeclStmt() {
@@ -1276,6 +1352,11 @@ class TranslatedJumpStmt extends TranslatedStmt {
   override JumpStmt stmt;
 
   override Instruction getFirstInstruction(EdgeKind kind) {
+    // The first instruction is a destructor call, if any.
+    result = this.getChildInternal(0).getFirstInstruction(kind)
+    or
+    // Otherwise, the first (and only) instruction is a `NoOp`
+    not exists(this.getChildInternal(0)) and
     result = this.getInstruction(OnlyInstructionTag()) and
     kind instanceof GotoEdge
   }
@@ -1284,7 +1365,20 @@ class TranslatedJumpStmt extends TranslatedStmt {
     result = this.getInstruction(OnlyInstructionTag())
   }
 
-  override TranslatedElement getChildInternal(int id) { none() }
+  private TranslatedCall getTranslatedImplicitDestructorCall(int id) {
+    result.getExpr() = stmt.getImplicitDestructorCall(id)
+  }
+
+  override TranslatedElement getLastChild() {
+    result =
+      this.getTranslatedImplicitDestructorCall(max(int id |
+          exists(stmt.getImplicitDestructorCall(id))
+        ))
+  }
+
+  override TranslatedElement getChildInternal(int id) {
+    result = this.getTranslatedImplicitDestructorCall(id)
+  }
 
   override predicate hasInstruction(Opcode opcode, InstructionTag tag, CppType resultType) {
     tag = OnlyInstructionTag() and
@@ -1297,7 +1391,19 @@ class TranslatedJumpStmt extends TranslatedStmt {
     result = getTranslatedStmt(stmt.getTarget()).getFirstInstruction(kind)
   }
 
-  override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) { none() }
+  final override predicate handlesDestructorsExplicitly() { any() }
+
+  override Instruction getChildSuccessorInternal(TranslatedElement child, EdgeKind kind) {
+    exists(int id | child = this.getChildInternal(id) |
+      // Transition to the next destructor call, if any.
+      result = this.getChildInternal(id + 1).getFirstInstruction(kind)
+      or
+      // And otherwise, exit this element by flowing to the target of the jump.
+      not exists(this.getChildInternal(id + 1)) and
+      kind instanceof GotoEdge and
+      result = this.getInstruction(OnlyInstructionTag())
+    )
+  }
 }
 
 private EdgeKind getCaseEdge(SwitchCase switchCase) {

cpp/ql/lib/semmle/code/cpp/ir/implementation/unaliased_ssa/IRVariable.qll

@@ -17,18 +17,11 @@ private import Imports::IRType
  * The variable may be a user-declared variable (`IRUserVariable`) or a temporary variable generated
  * by the AST-to-IR translation (`IRTempVariable`).
  */
-class IRVariable extends TIRVariable {
+abstract private class AbstractIRVariable extends TIRVariable {
   Language::Declaration func;
 
-  IRVariable() {
-    this = TIRUserVariable(_, _, func) or
-    this = TIRTempVariable(func, _, _, _) or
-    this = TIRStringLiteral(func, _, _, _) or
-    this = TIRDynamicInitializationFlag(func, _, _)
-  }
-
   /** Gets a textual representation of this element. */
-  string toString() { none() }
+  abstract string toString();
 
   /**
    * Holds if this variable's value cannot be changed within a function. Currently used for string
@@ -49,13 +42,13 @@ class IRVariable extends TIRVariable {
   /**
    * Gets the type of the variable.
    */
-  Language::LanguageType getLanguageType() { none() }
+  abstract Language::LanguageType getLanguageType();
 
   /**
    * Gets the AST node that declared this variable, or that introduced this
    * variable as part of the AST-to-IR translation.
    */
-  Language::AST getAst() { none() }
+  abstract Language::AST getAst();
 
   /** DEPRECATED: Alias for getAst */
   deprecated Language::AST getAST() { result = this.getAst() }
@@ -64,7 +57,7 @@ class IRVariable extends TIRVariable {
    * Gets an identifier string for the variable. This identifier is unique
    * within the function.
    */
-  string getUniqueId() { none() }
+  abstract string getUniqueId();
 
   /**
    * Gets the source location of this variable.
@@ -74,7 +67,7 @@ class IRVariable extends TIRVariable {
   /**
    * Gets the IR for the function that references this variable.
    */
-  final IRFunction getEnclosingIRFunction() { result.getFunction() = func }
+  final IRFunction getEnclosingIRFunction() { result.getFunction() = this.getEnclosingFunction() }
 
   /**
    * Gets the function that references this variable.
@@ -82,10 +75,18 @@ class IRVariable extends TIRVariable {
   final Language::Declaration getEnclosingFunction() { result = func }
 }
 
+/**
+ * A variable referenced by the IR for a function.
+ *
+ * The variable may be a user-declared variable (`IRUserVariable`) or a temporary variable generated
+ * by the AST-to-IR translation (`IRTempVariable`).
+ */
+final class IRVariable = AbstractIRVariable;
+
 /**
  * A user-declared variable referenced by the IR for a function.
  */
-class IRUserVariable extends IRVariable, TIRUserVariable {
+class IRUserVariable extends AbstractIRVariable, TIRUserVariable {
   Language::Variable var;
   Language::LanguageType type;
 
@@ -114,26 +115,29 @@ class IRUserVariable extends IRVariable, TIRUserVariable {
  * A variable (user-declared or temporary) that is allocated on the stack. This includes all
  * parameters, non-static local variables, and temporary variables.
  */
-class IRAutomaticVariable extends IRVariable {
-  IRAutomaticVariable() {
-    exists(Language::Variable var |
-      this = TIRUserVariable(var, _, func) and
-      Language::isVariableAutomatic(var)
-    )
-    or
-    this = TIRTempVariable(func, _, _, _)
-  }
+abstract private class AbstractIRAutomaticVariable extends AbstractIRVariable { }
+
+/**
+ * A variable (user-declared or temporary) that is allocated on the stack. This includes all
+ * parameters, non-static local variables, and temporary variables.
+ */
+final class IRAutomaticVariable = AbstractIRAutomaticVariable;
+
+/**
+ * A user-declared variable that is allocated on the stack. This includes all parameters and
+ * non-static local variables.
+ */
+private class AbstractIRAutomaticUserVariable extends IRUserVariable, AbstractIRAutomaticVariable {
+  override Language::AutomaticVariable var;
+
+  final override Language::AutomaticVariable getVariable() { result = var }
 }
 
 /**
  * A user-declared variable that is allocated on the stack. This includes all parameters and
  * non-static local variables.
  */
-class IRAutomaticUserVariable extends IRUserVariable, IRAutomaticVariable {
-  override Language::AutomaticVariable var;
-
-  final override Language::AutomaticVariable getVariable() { result = var }
-}
+final class IRAutomaticUserVariable = AbstractIRAutomaticUserVariable;
 
 /**
  * A user-declared variable that is not allocated on the stack. This includes all global variables,
@@ -151,16 +155,10 @@ class IRStaticUserVariable extends IRUserVariable {
  * A variable that is not user-declared. This includes temporary variables generated as part of IR
  * construction, as well as string literals.
  */
-class IRGeneratedVariable extends IRVariable {
+abstract private class AbstractIRGeneratedVariable extends AbstractIRVariable {
   Language::AST ast;
   Language::LanguageType type;
 
-  IRGeneratedVariable() {
-    this = TIRTempVariable(func, ast, _, type) or
-    this = TIRStringLiteral(func, ast, type, _) or
-    this = TIRDynamicInitializationFlag(func, ast, type)
-  }
-
   final override Language::LanguageType getLanguageType() { result = type }
 
   final override Language::AST getAst() { result = ast }
@@ -196,12 +194,20 @@ class IRGeneratedVariable extends IRVariable {
   string getBaseString() { none() }
 }
 
+/**
+ * A variable that is not user-declared. This includes temporary variables generated as part of IR
+ * construction, as well as string literals.
+ */
+final class IRGeneratedVariable = AbstractIRGeneratedVariable;
+
 /**
  * A temporary variable introduced by IR construction. The most common examples are the variable
  * generated to hold the return value of a function, or the variable generated to hold the result of
  * a condition operator (`a ? b : c`).
  */
-class IRTempVariable extends IRGeneratedVariable, IRAutomaticVariable, TIRTempVariable {
+class IRTempVariable extends AbstractIRGeneratedVariable, AbstractIRAutomaticVariable,
+  TIRTempVariable
+{
   TempVariableTag tag;
 
   IRTempVariable() { this = TIRTempVariable(func, ast, tag, type) }
@@ -241,7 +247,7 @@ class IRThrowVariable extends IRTempVariable {
  * A temporary variable generated to hold the contents of all arguments passed to the `...` of a
  * function that accepts a variable number of arguments.
  */
-class IREllipsisVariable extends IRTempVariable, IRParameter {
+class IREllipsisVariable extends IRTempVariable, AbstractIRParameter {
   IREllipsisVariable() { tag = EllipsisTempVar() }
 
   final override string toString() { result = "#ellipsis" }
@@ -252,7 +258,7 @@ class IREllipsisVariable extends IRTempVariable, IRParameter {
 /**
  * A temporary variable generated to hold the `this` pointer.
  */
-class IRThisVariable extends IRTempVariable, IRParameter {
+class IRThisVariable extends IRTempVariable, AbstractIRParameter {
   IRThisVariable() { tag = ThisTempVar() }
 
   final override string toString() { result = "#this" }
@@ -264,7 +270,7 @@ class IRThisVariable extends IRTempVariable, IRParameter {
  * A variable generated to represent the contents of a string literal. This variable acts much like
  * a read-only global variable.
  */
-class IRStringLiteral extends IRGeneratedVariable, TIRStringLiteral {
+class IRStringLiteral extends AbstractIRGeneratedVariable, TIRStringLiteral {
   Language::StringLiteral literal;
 
   IRStringLiteral() { this = TIRStringLiteral(func, ast, type, literal) }
@@ -288,7 +294,7 @@ class IRStringLiteral extends IRGeneratedVariable, TIRStringLiteral {
  * used to model the runtime initialization of static local variables in C++, as well as static
  * fields in C#.
  */
-class IRDynamicInitializationFlag extends IRGeneratedVariable, TIRDynamicInitializationFlag {
+class IRDynamicInitializationFlag extends AbstractIRGeneratedVariable, TIRDynamicInitializationFlag {
   Language::Variable var;
 
   IRDynamicInitializationFlag() {
@@ -314,24 +320,24 @@ class IRDynamicInitializationFlag extends IRGeneratedVariable, TIRDynamicInitial
  * An IR variable which acts like a function parameter, including positional parameters and the
  * temporary variables generated for `this` and ellipsis parameters.
  */
-class IRParameter extends IRAutomaticVariable {
-  IRParameter() {
-    this.(IRAutomaticUserVariable).getVariable() instanceof Language::Parameter
-    or
-    this = TIRTempVariable(_, _, ThisTempVar(), _)
-    or
-    this = TIRTempVariable(_, _, EllipsisTempVar(), _)
-  }
-
+abstract private class AbstractIRParameter extends AbstractIRAutomaticVariable {
   /**
    * Gets the zero-based index of this parameter. The `this` parameter has index -1.
    */
   int getIndex() { none() }
 }
 
+/**
+ * An IR variable which acts like a function parameter, including positional parameters and the
+ * temporary variables generated for `this` and ellipsis parameters.
+ */
+final class IRParameter = AbstractIRParameter;
+
 /**
  * An IR variable representing a positional parameter.
  */
-class IRPositionalParameter extends IRParameter, IRAutomaticUserVariable {
+class IRPositionalParameter extends AbstractIRParameter, AbstractIRAutomaticUserVariable {
+  IRPositionalParameter() { this.getVariable() instanceof Language::Parameter }
+
   final override int getIndex() { result = this.getVariable().(Language::Parameter).getIndex() }
 }

cpp/ql/lib/semmle/code/cpp/models/implementations/Iterator.qll

@@ -560,7 +560,7 @@ private class IteratorAssignmentMemberOperatorModel extends IteratorAssignmentMe
   TaintFunction, SideEffectFunction, AliasFunction
 {
   override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
-    input.isParameterDeref(0) and
+    (input.isParameterDeref(0) or input.isParameter(0)) and
     output.isQualifierObject()
   }
 
@@ -579,17 +579,34 @@ private class IteratorAssignmentMemberOperatorModel extends IteratorAssignmentMe
   override predicate parameterEscapesOnlyViaReturn(int index) { index = -1 }
 }
 
+/**
+ * A `begin` member function, or a related function, that returns an iterator.
+ */
+class BeginFunction extends MemberFunction {
+  BeginFunction() {
+    this.hasName(["begin", "cbegin", "rbegin", "crbegin", "before_begin", "cbefore_begin"]) and
+    this.getType().getUnspecifiedType() instanceof Iterator
+  }
+}
+
+/**
+ * An `end` member function, or a related function, that returns an iterator.
+ */
+class EndFunction extends MemberFunction {
+  EndFunction() {
+    this.hasName(["end", "cend", "rend", "crend"]) and
+    this.getType().getUnspecifiedType() instanceof Iterator
+  }
+}
+
 /**
  * A `begin` or `end` member function, or a related member function, that
  * returns an iterator.
  */
 class BeginOrEndFunction extends MemberFunction {
   BeginOrEndFunction() {
-    this.hasName([
-        "begin", "cbegin", "rbegin", "crbegin", "end", "cend", "rend", "crend", "before_begin",
-        "cbefore_begin"
-      ]) and
-    this.getType().getUnspecifiedType() instanceof Iterator
+    this instanceof BeginFunction or
+    this instanceof EndFunction
   }
 }
 

cpp/ql/lib/upgrades/ddd31fd02e51ad270bc9e6712708e5a5b6881518/upgrade.properties

@@ -1,4 +1,4 @@
 description: Removed unused column from the `folders` and `files` relations
 compatibility: full
-files.rel: reorder files.rel (int id, string name, string simple, string ext, int fromSource) id name
-folders.rel: reorder folders.rel (int id, string name, string simple) id name
+files.rel: reorder files.rel (@file id, string name, string simple, string ext, int fromSource) id name
+folders.rel: reorder folders.rel (@folder id, string name, string simple) id name

cpp/ql/src/CHANGELOG.md

@@ -1,3 +1,26 @@
+## 1.0.1
+
+### Minor Analysis Improvements
+
+* The `cpp/dangerous-function-overflow` no longer produces a false positive alert when the `gets` function does not have exactly one parameter.
+
+## 1.0.0
+
+### Breaking Changes
+
+* CodeQL package management is now generally available, and all GitHub-produced CodeQL packages have had their version numbers increased to 1.0.0.
+
+### Minor Analysis Improvements
+
+* The "Use of unique pointer after lifetime ends" query (`cpp/use-of-unique-pointer-after-lifetime-ends`) no longer reports an alert when the pointer is converted to a boolean
+* The "Variable not initialized before use" query (`cpp/not-initialised`) no longer reports an alert on static variables.
+
+## 0.9.12
+
+### New Queries
+
+* Added a new query, `cpp/iterator-to-expired-container`, to detect the creation of iterators owned by a temporary objects that are about to be destroyed.
+
 ## 0.9.11
 
 ### Minor Analysis Improvements

cpp/ql/src/Critical/DoubleFree.qhelp

@@ -14,13 +14,32 @@ the program, or security vulnerabilities, by allowing an attacker to overwrite a
 </overview>
 <recommendation>
 <p>
-Ensure that all execution paths deallocate the allocated memory at most once. If possible, reassign
-the pointer to a null value after deallocating it. This will prevent double-free vulnerabilities since
-most deallocation functions will perform a null-pointer check before attempting to deallocate the memory.
+Ensure that all execution paths deallocate the allocated memory at most once. In complex cases it may
+help to reassign a pointer to a null value after deallocating it. This will prevent double-free vulnerabilities
+since most deallocation functions will perform a null-pointer check before attempting to deallocate memory.
 </p>
 
 </recommendation>
-<example><sample src="DoubleFree.cpp" />
+<example>
+<p>
+In the following example, <code>buff</code> is allocated and then freed twice:
+</p>
+<sample src="DoubleFreeBad.cpp" />
+<p>
+Reviewing the code above, the issue can be fixed by simply deleting the additional call to
+<code>free(buff)</code>.
+</p>
+<sample src="DoubleFreeGood.cpp" />
+<p>
+In the next example, <code>task</code> may be deleted twice, if an exception occurs inside the <code>try</code>
+block after the first <code>delete</code>:
+</p>
+<sample src="DoubleFreeBad2.cpp" />
+<p>
+The problem can be solved by assigning a null value to the pointer after the first <code>delete</code>, as
+calling <code>delete</code> a second time on the null pointer is harmless.
+</p>
+<sample src="DoubleFreeGood2.cpp" />
 </example>
 <references>
 

cpp/ql/src/Critical/DoubleFreeBad2.cpp

@@ -0,0 +1,16 @@
+void g() {
+	MyTask *task = nullptr;
+
+	try
+	{
+		task = new MyTask;
+
+		...
+
+		delete task;
+
+		...
+	} catch (...) {
+		delete task; // BAD: potential double-free
+	}
+}

cpp/ql/src/Critical/DoubleFreeGood.cpp

@@ -0,0 +1,7 @@
+int* f() {
+	int *buff = malloc(SIZE*sizeof(int));
+	do_stuff(buff);
+	free(buff); // GOOD: buff is only freed once.
+	int *new_buffer = malloc(SIZE*sizeof(int));
+	return new_buffer;
+}

cpp/ql/src/Critical/DoubleFreeGood2.cpp

@@ -0,0 +1,17 @@
+void g() {
+	MyTask *task = nullptr;
+
+	try
+	{
+		task = new MyTask;
+
+		...
+
+		delete task;
+		task = nullptr;
+
+		...
+	} catch (...) {
+		delete task; // GOOD: harmless if task is NULL
+	}
+}

cpp/ql/src/Critical/NotInitialised.ql

@@ -54,6 +54,7 @@ predicate undefinedLocalUse(VariableAccess va) {
     // it is hard to tell when a struct or array has been initialized, so we
     // ignore them
     not isAggregateType(lv.getUnderlyingType()) and
+    not lv.isStatic() and // static variables are initialized to zero or null by default
     not lv.getType().hasName("va_list") and
     va = lv.getAnAccess() and
     noDefPath(lv, va) and
@@ -70,7 +71,8 @@ predicate uninitialisedGlobal(GlobalVariable gv) {
     va = gv.getAnAccess() and
     va.isRValue() and
     not gv.hasInitializer() and
-    not gv.hasSpecifier("extern")
+    not gv.hasSpecifier("extern") and
+    not gv.isStatic() // static variables are initialized to zero or null by default
   )
 }
 

cpp/ql/src/Likely Bugs/Format/NonConstantFormat.qhelp

@@ -42,7 +42,7 @@ in the previous example, one solution is to make the log message a trailing argu
 <p>An alternative solution is to allow <code>log_with_timestamp</code> to accept format arguments:</p>
 <sample src="NonConstantFormat-2-good.c" />
 <p>In this formulation, the non-constant format string to <code>printf</code> has been replaced with
-a non-constant format string to <code>vprintf</code>. Semmle will no longer consider the body of
+a non-constant format string to <code>vprintf</code>. The analysis will no longer consider the body of
 <code>log_with_timestamp</code> to be a problem, and will instead check that every call to
 <code>log_with_timestamp</code> passes a constant format string.</p>
 

cpp/ql/src/Likely Bugs/Format/TooManyFormatArguments.qhelp

@@ -22,10 +22,8 @@ function.
 </example>
 <references>
 
-<li>cplusplus.com: <a href="http://www.tutorialspoint.com/cplusplus/cpp_functions.htm">C++ Functions</a>.</li>
+<li>CERT C Coding Standard: <a href="https://wiki.sei.cmu.edu/confluence/display/c/FIO47-C.+Use+valid+format+strings">FIO47-C. Use valid format strings</a>.</li>
 <li>Microsoft C Runtime Library Reference: <a href="https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/printf-printf-l-wprintf-wprintf-l">printf, wprintf</a>.</li>
 
-
-
 </references>
 </qhelp>

cpp/ql/src/Likely Bugs/Format/WrongNumberOfFormatArguments.qhelp

@@ -19,8 +19,8 @@ contents.
 
 </overview>
 <recommendation>
-<p>Review the format and arguments expected by the highlighted function calls. Update either 
-the format or the arguments so that the expected number of arguments are passed to the 
+<p>Review the format and arguments expected by the highlighted function calls. Update either
+the format or the arguments so that the expected number of arguments are passed to the
 function.
 </p>
 
@@ -30,11 +30,8 @@ function.
 </example>
 <references>
 
-<li>CERT C Coding
-Standard: <a href="https://www.securecoding.cert.org/confluence/display/c/FIO30-C.+Exclude+user+input+from+format+strings">FIO30-C. Exclude user input from format strings</a>.</li>
-<li>cplusplus.com: <a href="http://www.tutorialspoint.com/cplusplus/cpp_functions.htm">C++ Functions</a>.</li>
+<li>CERT C Coding Standard: <a href="https://wiki.sei.cmu.edu/confluence/display/c/FIO47-C.+Use+valid+format+strings">FIO47-C. Use valid format strings</a>.</li>
 <li>Microsoft C Runtime Library Reference: <a href="https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/printf-printf-l-wprintf-wprintf-l">printf, wprintf</a>.</li>
 
-
 </references>
 </qhelp>

cpp/ql/src/Likely Bugs/Format/WrongTypeFormatArguments.cpp

@@ -1,4 +0,0 @@
-int main() {
-  printf("%s\n", 42); //printf will treat 42 as a char*, will most likely segfault
-  return 0;
-}

cpp/ql/src/Likely Bugs/Format/WrongTypeFormatArguments.qhelp

@@ -4,29 +4,33 @@
 <qhelp>
 <overview>
 <p>Each call to the <code>printf</code> function or a related function should include
-the type and sequence of arguments defined by the format. If the function is passed arguments 
+the type and sequence of arguments defined by the format. If the function is passed arguments
 of a different type or in a different sequence then the arguments are reinterpreted to fit the type and sequence expected, resulting in unpredictable behavior.</p>
 
 </overview>
 <recommendation>
-<p>Review the format and arguments expected by the highlighted function calls. Update either 
-the format or the arguments so that the expected type and sequence of arguments are passed to 
+<p>Review the format and arguments expected by the highlighted function calls. Update either
+the format or the arguments so that the expected type and sequence of arguments are passed to
 the function.
 </p>
 
 </recommendation>
-<example><sample src="WrongTypeFormatArguments.cpp" />
+<example>
+
+<p>In the following example, the wrong format specifier is given for an integer format argument:</p>
+
+<sample src="WrongTypeFormatArgumentsBad.cpp" />
+
+<p>The corrected version uses <code>%i</code> as the format specifier for the integer format argument:</p>
+
+<sample src="WrongTypeFormatArgumentsGood.cpp" />
 
 </example>
 <references>
 
-<li>CERT C Coding
-Standard: <a href="https://www.securecoding.cert.org/confluence/display/c/FIO30-C.+Exclude+user+input+from+format+strings">FIO30-C. Exclude user input from format strings</a>.</li>
-<li>cplusplus.com: <a href="http://www.tutorialspoint.com/cplusplus/cpp_functions.htm">C++ Functions</a>.</li>
-<li>CRT Alphabetical Function Reference: <a href="https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/printf-printf-l-wprintf-wprintf-l">printf, _printf_l, wprintf, _wprintf_l</a>.</li>
-
-
-
+<li>Microsoft Learn: <a href="https://learn.microsoft.com/en-us/cpp/c-runtime-library/format-specification-syntax-printf-and-wprintf-functions?view=msvc-170">Format specification syntax: printf and wprintf functions</a>.</li>
+<li>cplusplus.com:<a href="https://cplusplus.com/reference/cstdio/printf/"></a>printf</li>
+<li>CERT C Coding Standard: <a href="https://wiki.sei.cmu.edu/confluence/display/c/FIO47-C.+Use+valid+format+strings">FIO47-C. Use valid format strings</a>.</li>
 
 </references>
 </qhelp>

cpp/ql/src/Likely Bugs/Format/WrongTypeFormatArgumentsBad.cpp

@@ -0,0 +1,4 @@
+int main() {
+  printf("%s\n", 42); // BAD: printf will treat 42 as a char*, will most likely segfault
+  return 0;
+}

cpp/ql/src/Likely Bugs/Format/WrongTypeFormatArgumentsGood.cpp

@@ -0,0 +1,4 @@
+int main() {
+  printf("%i\n", 42); // GOOD: printf will treat 42 as an int
+  return 0;
+}

cpp/ql/src/Likely Bugs/Likely Typos/IncorrectNotOperatorUsage.cpp

@@ -2,19 +2,18 @@
 
 void f_warning(int i)
 {
-    // The usage of the logical not operator in this case is unlikely to be correct
+    // BAD: the usage of the logical not operator in this case is unlikely to be correct
     // as the output is being used as an operator for a bit-wise and operation
-    if (i & !FLAGS) 
+    if (i & !FLAGS)
     {
         // code
     }
 }
 
-
 void f_fixed(int i)
 {
-    if (i & ~FLAGS) // Changing the logical not operator for the bit-wise not operator would fix this logic
+    if (i & ~FLAGS) // GOOD: Changing the logical not operator for the bit-wise not operator would fix this logic
     {
         // code
     }
-}
+}

cpp/ql/src/Likely Bugs/Likely Typos/IncorrectNotOperatorUsage.qhelp

@@ -16,7 +16,13 @@
 <p>Carefully inspect the flagged expressions. Consider the intent in the code logic, and decide whether it is necessary to change the not operator.</p>
 </recommendation>
 
-<example><sample src="IncorrectNotOperatorUsage.cpp" /></example>
+<example>
+<p>Here is an example of this issue and how it can be fixed:</p>
+
+<sample src="IncorrectNotOperatorUsage.cpp" />
+
+<p>In other cases, particularly when the expressions have <code>bool</code> type, the fix may instead be of the form <code>a &amp;&amp; !b</code>.</p>
+</example>
 
 <references>
   <li>

cpp/ql/src/Likely Bugs/Memory Management/AllocaInLoop.ql

@@ -37,6 +37,19 @@ class AllocaCall extends FunctionCall {
   }
 }
 
+/**
+ * Gets an expression associated with a dataflow node.
+ */
+private Expr getExpr(DataFlow::Node node) {
+  result = node.asInstruction().getAst()
+  or
+  result = node.asOperand().getUse().getAst()
+  or
+  result = node.(DataFlow::RawIndirectInstruction).getInstruction().getAst()
+  or
+  result = node.(DataFlow::RawIndirectOperand).getOperand().getUse().getAst()
+}
+
 /**
  * A loop that contains an `alloca` call.
  */
@@ -185,19 +198,6 @@ class LoopWithAlloca extends Stmt {
     not this.conditionReachesWithoutUpdate(var, this.(Loop).getCondition())
   }
 
-  /**
-   * Gets an expression associated with a dataflow node.
-   */
-  private Expr getExpr(DataFlow::Node node) {
-    result = node.asInstruction().getAst()
-    or
-    result = node.asOperand().getUse().getAst()
-    or
-    result = node.(DataFlow::RawIndirectInstruction).getInstruction().getAst()
-    or
-    result = node.(DataFlow::RawIndirectOperand).getOperand().getUse().getAst()
-  }
-
   /**
    * Gets a definition that may be the most recent definition of the
    * controlling variable `var` before this loop.
@@ -209,8 +209,9 @@ class LoopWithAlloca extends Stmt {
       DataFlow::localFlow(result, DataFlow::exprNode(va)) and
       // Phi nodes will be preceded by nodes that represent actual definitions
       not result instanceof DataFlow::SsaPhiNode and
+      not result instanceof DataFlow::SsaPhiInputNode and
       // A source is outside the loop if it's not inside the loop
-      not exists(Expr e | e = this.getExpr(result) | this = getAnEnclosingLoopOfExpr(e))
+      not exists(Expr e | e = getExpr(result) | this = getAnEnclosingLoopOfExpr(e))
     )
   }
 
@@ -221,9 +222,9 @@ class LoopWithAlloca extends Stmt {
   private int getAControllingVarInitialValue(Variable var, DataFlow::Node source) {
     source = this.getAPrecedingDef(var) and
     (
-      result = this.getExpr(source).getValue().toInt()
+      result = getExpr(source).getValue().toInt()
       or
-      result = this.getExpr(source).(Assignment).getRValue().getValue().toInt()
+      result = getExpr(source).(Assignment).getRValue().getValue().toInt()
     )
   }
 

cpp/ql/src/Likely Bugs/Memory Management/NtohlArrayNoBound.qll

@@ -107,7 +107,7 @@ class SnprintfSizeExpr extends BufferAccess, FunctionCall {
 }
 
 class MemcmpSizeExpr extends BufferAccess, FunctionCall {
-  MemcmpSizeExpr() { this.getTarget().hasName("Memcmp") }
+  MemcmpSizeExpr() { this.getTarget().hasName("memcmp") }
 
   override Expr getPointer() {
     result = this.getArgument(0) or

cpp/ql/src/Likely Bugs/Memory Management/StrncpyFlippedArgs.cpp

@@ -1,2 +0,0 @@
-strncpy(dest, src, sizeof(src)); //wrong: size of dest should be used
-strncpy(dest, src, strlen(src)); //wrong: size of dest should be used

cpp/ql/src/Likely Bugs/Memory Management/StrncpyFlippedArgs.qhelp

@@ -3,7 +3,7 @@
   "qhelp.dtd">
 <qhelp>
 <overview>
-<p>The standard library function <code>strncpy</code> copies a source string to a destination buffer. The third argument defines the maximum number of characters to copy and should be less than 
+<p>The standard library function <code>strncpy</code> copies a source string to a destination buffer. The third argument defines the maximum number of characters to copy and should be less than
 or equal to the size of the destination buffer. Calls of the form <code>strncpy(dest, src, strlen(src))</code> or <code>strncpy(dest, src, sizeof(src))</code> incorrectly set the third argument to the size of the source buffer. Executing a call of this type may cause a buffer overflow. Buffer overflows can lead to anything from a segmentation fault to a security vulnerability.</p>
 
 </overview>
@@ -12,14 +12,20 @@ or equal to the size of the destination buffer. Calls of the form <code>strncpy(
 not the source buffer.</p>
 
 </recommendation>
-<example><sample src="StrncpyFlippedArgs.cpp" />
 
+<example>
+<p>In the following examples, the size of the source buffer is incorrectly used as a parameter to <code>strncpy</code>:</p>
 
+<sample src="StrncpyFlippedArgsBad.cpp" />
 
+<p>The corrected version uses the size of the destination buffer, or a variable containing the size of the destination buffer as the size parameter to <code>strncpy</code>:</p>
+
+<sample src="StrncpyFlippedArgsGood.cpp" />
 </example>
+
 <references>
 
-<li>cplusplus.com: <a href="http://www.cplusplus.com/reference/clibrary/cstring/strncpy/">strncpy</a>.</li>
+<li>cplusplus.com: <a href="https://cplusplus.com/reference/cstring/strncpy/">strncpy</a>.</li>
 <li>
   I. Gerg. <em>An Overview and Example of the Buffer-Overflow Exploit</em>. IANewsletter vol 7 no 4. 2005.
 </li>

cpp/ql/src/Likely Bugs/Memory Management/StrncpyFlippedArgsBad.cpp

@@ -0,0 +1,9 @@
+char src[256];
+char dest1[128];
+
+...
+
+strncpy(dest1, src, sizeof(src)); // wrong: size of dest should be used
+
+char *dest2 = (char *)malloc(sz1 + sz2 + sz3);
+strncpy(dest2, src, strlen(src)); // wrong: size of dest should be used

cpp/ql/src/Likely Bugs/Memory Management/StrncpyFlippedArgsGood.cpp

@@ -0,0 +1,10 @@
+char src[256];
+char dest1[128];
+
+...
+
+strncpy(dest1, src, sizeof(dest1)); // correct
+
+size_t destSize = sz1 + sz2 + sz3;
+char *dest2 = (char *)malloc(destSize);
+strncpy(dest2, src, destSize); // correct

cpp/ql/src/Security/CWE/CWE-022/TaintedPath.c

@@ -1,22 +0,0 @@
-int main(int argc, char** argv) {
-  char *userAndFile = argv[2];
-  
-  {
-    char fileBuffer[FILENAME_MAX] = "/home/";
-    char *fileName = fileBuffer;
-    size_t len = strlen(fileName);
-    strncat(fileName+len, userAndFile, FILENAME_MAX-len-1);
-    // BAD: a string from the user is used in a filename
-    fopen(fileName, "wb+");
-  }
-
-  {
-    char fileBuffer[FILENAME_MAX] = "/home/";
-    char *fileName = fileBuffer;
-    size_t len = strlen(fileName);
-    // GOOD: use a fixed file
-    char* fixed = "jim/file.txt";
-    strncat(fileName+len, fixed, FILENAME_MAX-len-1);
-    fopen(fileName, "wb+");
-  }
-}

cpp/ql/src/Security/CWE/CWE-022/TaintedPath.qhelp

@@ -3,36 +3,57 @@
   "qhelp.dtd">
 <qhelp>
 <overview>
-<p>Accessing paths controlled by users can allow an attacker to access unexpected resources. This
+<p>Accessing paths controlled by users can allow an attacker to access unexpected resources. This 
 can result in sensitive information being revealed or deleted, or an attacker being able to influence
 behavior by modifying unexpected files.</p>
 
-<p>Paths that are naively constructed from data controlled by a user may contain unexpected special characters,
-such as "..". Such a path may potentially point to any directory on the filesystem.</p>
+<p>Paths that are naively constructed from data controlled by a user may be absolute paths, or may contain
+unexpected special characters such as "..". Such a path could point anywhere on the file system.</p>
 
 </overview>
 <recommendation>
 
-<p>Validate user input before using it to construct a filepath. Ideally, follow these rules:</p>
+<p>Validate user input before using it to construct a file path.</p>
 
-<ul>
-<li>Do not allow more than a single "." character.</li>
-<li>Do not allow directory separators such as "/" or "\" (depending on the filesystem).</li>
-<li>Do not rely on simply replacing problematic sequences such as "../". For example, after applying this filter to
-".../...//" the resulting string would still be "../".</li>
-<li>Ideally use a whitelist of known good patterns.</li>
-</ul>
+<p>Common validation methods include checking that the normalized path is relative and does not contain
+any ".." components, or checking that the path is contained within a safe folder. The method you should use depends 
+on how the path is used in the application, and whether the path should be a single path component.
+</p>
+
+<p>If the path should be a single path component (such as a file name), you can check for the existence 
+of any path separators ("/" or "\"), or ".." sequences in the input, and reject the input if any are found.
+</p>
+
+<p>
+Note that removing "../" sequences is <i>not</i> sufficient, since the input could still contain a path separator
+followed by "..". For example, the input ".../...//" would still result in the string "../" if only "../" sequences
+are removed.
+</p>
+
+<p>Finally, the simplest (but most restrictive) option is to use an allow list of safe patterns and make sure that
+the user input matches one of these patterns.</p>
 
 </recommendation>
 <example>
 
-<p>In this example, a username and file are read from the arguments to main and then used to access a file in the
-user's home directory. However, a malicious user could enter a filename which contains special
-characters. For example, the string "../../etc/passwd" will result in the code reading the file located at
-"/home/[user]/../../etc/passwd", which is the system's password file. This could potentially allow them to
-access all the system's passwords.</p>
+<p>In this example, a file name is read from a user and then used to access a file. 
+However, a malicious user could enter a file name anywhere on the file system,
+such as "/etc/passwd" or "../../../etc/passwd".</p>
 
-<sample src="TaintedPath.c" />
+<sample src="examples/TaintedPath.c" />
+
+<p>
+If the input should only be a file name, you can check that it doesn't contain any path separators or ".." sequences.
+</p>
+
+<sample src="examples/TaintedPathNormalize.c" />
+
+<p>
+If the input should be within a specific directory, you can check that the resolved path 
+is still contained within that directory.
+</p>
+
+<sample src="examples/TaintedPathFolder.c" />
 
 </example>
 <references>
@@ -41,6 +62,7 @@ access all the system's passwords.</p>
 OWASP:
 <a href="https://owasp.org/www-community/attacks/Path_Traversal">Path Traversal</a>.
 </li>
+<li>Linux man pages: <a href="https://man7.org/linux/man-pages/man3/realpath.3.html">realpath(3)</a>.</li>
 
 </references>
 </qhelp>

cpp/ql/src/Security/CWE/CWE-022/examples/TaintedPath.c

@@ -0,0 +1,10 @@
+int main(int argc, char** argv) {
+  char *userAndFile = argv[2];
+  
+  {
+    char fileBuffer[PATH_MAX];
+    snprintf(fileBuffer, sizeof(fileBuffer), "/home/%s", userAndFile);
+    // BAD: a string from the user is used in a filename
+    fopen(fileBuffer, "wb+");
+  }
+}

cpp/ql/src/Security/CWE/CWE-022/examples/TaintedPathFolder.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <string.h>
+
+int main(int argc, char** argv) {
+    char *userAndFile = argv[2];
+    const char *baseDir = "/home/user/public/";
+    char fullPath[PATH_MAX];
+
+    // Attempt to concatenate the base directory and the user-supplied path
+    snprintf(fullPath, sizeof(fullPath), "%s%s", baseDir, userAndFile);
+
+    // Resolve the absolute path, normalizing any ".." or "."
+    char *resolvedPath = realpath(fullPath, NULL);
+    if (resolvedPath == NULL) {
+        perror("Error resolving path");
+        return 1;
+    }
+
+    // Check if the resolved path starts with the base directory
+    if (strncmp(baseDir, resolvedPath, strlen(baseDir)) != 0) {
+        free(resolvedPath);
+        return 1;
+    }
+
+    // GOOD: Path is within the intended directory
+    FILE *file = fopen(resolvedPath, "wb+");
+    free(resolvedPath);
+}

cpp/ql/src/Security/CWE/CWE-022/examples/TaintedPathNormalize.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <string.h>
+
+int main(int argc, char** argv) {
+    char *fileName = argv[2];
+    // Check for invalid sequences in the user input
+    if (strstr(fileName , "..") || strchr(fileName , '/') || strchr(fileName , '\\')) {
+        printf("Invalid filename.\n");
+        return 1;
+    }
+
+    char fileBuffer[PATH_MAX];
+    snprintf(fileBuffer, sizeof(fileBuffer), "/home/user/files/%s", fileName);
+    // GOOD: We know that the filename is safe and stays within the public folder
+    FILE *file = fopen(fileBuffer, "wb+");
+}

cpp/ql/src/Security/CWE/CWE-131/NoSpaceForZeroTerminator.qhelp

@@ -12,8 +12,8 @@ the required buffer size, but do not allocate space for the zero terminator.
 </overview>
 <recommendation>
 <p>
-The expression highlighted by this rule creates a buffer that is of insufficient size to contain
-the data being copied. This makes the code vulnerable to buffer overflow which can result in anything from a segmentation fault to a security vulnerability (particularly if the array is on stack-allocated memory).
+The highlighted code segment creates a buffer without ensuring it's large enough to accommodate the copied data.
+This leaves the code susceptible to a buffer overflow attack, which could lead to anything from program crashes to malicious code execution.
 </p>
 
 <p>

cpp/ql/src/Security/CWE/CWE-416/IteratorToExpiredContainer.qhelp

@@ -30,6 +30,12 @@ This is because the temporary container is not bound to a rvalue reference.
 </p>
 <sample src="IteratorToExpiredContainerExtendedLifetime.cpp" />
 
+<p>
+To fix <code>lifetime_of_temp_not_extended</code>, consider rewriting the code so that the lifetime of the temporary object is extended.
+In <code>fixed_lifetime_of_temp_not_extended</code>, the lifetime of the temporary object has been extended by storing it in an rvalue reference.
+</p>
+<sample src="IteratorToExpiredContainerExtendedLifetime-fixed.cpp" />
+
 </example>
 <references>
 

cpp/ql/src/Security/CWE/CWE-416/IteratorToExpiredContainer.ql

@@ -2,9 +2,10 @@
  * @name Iterator to expired container
  * @description Using an iterator owned by a container whose lifetime has expired may lead to unexpected behavior.
  * @kind problem
- * @precision high
+ * @precision medium
  * @id cpp/iterator-to-expired-container
  * @problem.severity warning
+ * @security-severity 8.8
  * @tags reliability
  *       security
  *       external/cwe/cwe-416
@@ -61,14 +62,38 @@ DataFlow::Node getADestroyedNode(DataFlow::Node n) {
   )
 }
 
-predicate destroyedToBeginSink(DataFlow::Node sink, FunctionCall fc) {
+predicate destroyedToBeginSink(DataFlow::Node sink) {
   exists(CallInstruction call |
     call = sink.asOperand().(ThisArgumentOperand).getCall() and
-    fc = call.getUnconvertedResultExpression() and
     call.getStaticCallTarget() instanceof BeginOrEndFunction
   )
 }
 
+/**
+ * Holds if `node1` is the node corresponding to a qualifier of a destructor
+ * call and `node2` is a node that is destroyed as a result of `node1` being
+ * destroyed.
+ */
+private predicate qualifierToDestroyed(DataFlow::Node node1, DataFlow::Node node2) {
+  tempToDestructorSink(node1, _) and
+  node2 = getADestroyedNode(node1)
+}
+
+/**
+ * A configuration to track flow from a destroyed node to a qualifier of
+ * a `begin` or `end` function call.
+ *
+ * This configuration exists to prevent a cartesian product between all sinks and
+ * all states in `Config::isSink`.
+ */
+module Config0 implements DataFlow::ConfigSig {
+  predicate isSource(DataFlow::Node source) { qualifierToDestroyed(_, source) }
+
+  predicate isSink(DataFlow::Node sink) { destroyedToBeginSink(sink) }
+}
+
+module Flow0 = DataFlow::Global<Config0>;
+
 /**
  * A configuration to track flow from a temporary variable to the qualifier of
  * a destructor call, and subsequently to a qualifier of a call to `begin` or
@@ -78,12 +103,15 @@ module Config implements DataFlow::StateConfigSig {
   newtype FlowState =
     additional TempToDestructor() or
     additional DestroyedToBegin(DataFlow::Node n) {
-      exists(DataFlow::Node thisOperand |
-        tempToDestructorSink(thisOperand, _) and
-        n = getADestroyedNode(thisOperand)
-      )
+      any(Flow0::PathNode pn | pn.isSource()).getNode() = n
     }
 
+  /**
+   * Holds if `sink` is a qualifier to a call to `begin`, and `mid` is an
+   * object that is destroyed.
+   */
+  private predicate relevant(DataFlow::Node mid, DataFlow::Node sink) { Flow0::flow(mid, sink) }
+
   predicate isSource(DataFlow::Node source, FlowState state) {
     source.asInstruction().(VariableAddressInstruction).getIRVariable() instanceof IRTempVariable and
     state = TempToDestructor()
@@ -92,16 +120,16 @@ module Config implements DataFlow::StateConfigSig {
   predicate isAdditionalFlowStep(
     DataFlow::Node node1, FlowState state1, DataFlow::Node node2, FlowState state2
   ) {
-    tempToDestructorSink(node1, _) and
     state1 = TempToDestructor() and
     state2 = DestroyedToBegin(node2) and
-    node2 = getADestroyedNode(node1)
+    qualifierToDestroyed(node1, node2)
   }
 
   predicate isSink(DataFlow::Node sink, FlowState state) {
-    // Note: This is a non-trivial cartesian product!
-    // Hopefully, both of these sets are quite small in practice
-    destroyedToBeginSink(sink, _) and state instanceof DestroyedToBegin
+    exists(DataFlow::Node mid |
+      relevant(mid, sink) and
+      state = DestroyedToBegin(mid)
+    )
   }
 
   DataFlow::FlowFeature getAFeature() {
@@ -121,9 +149,9 @@ module Config implements DataFlow::StateConfigSig {
 
 module Flow = DataFlow::GlobalWithState<Config>;
 
-from Flow::PathNode source, Flow::PathNode sink, FunctionCall beginOrEnd, DataFlow::Node mid
+from Flow::PathNode source, Flow::PathNode sink, DataFlow::Node mid
 where
   Flow::flowPath(source, sink) and
-  destroyedToBeginSink(sink.getNode(), beginOrEnd) and
+  destroyedToBeginSink(sink.getNode()) and
   sink.getState() = Config::DestroyedToBegin(mid)
-select mid, "This object is destroyed before $@ is called.", beginOrEnd, beginOrEnd.toString()
+select mid, "This object is destroyed at the end of the full-expression."

cpp/ql/src/Security/CWE/CWE-416/IteratorToExpiredContainerExtendedLifetime-fixed.cpp

@@ -0,0 +1,6 @@
+void fixed_lifetime_of_temp_not_extended() {
+  auto&& v = get_vector();
+  for(auto x : log_and_return_argument(v)) {
+    use(x); // GOOD: The lifetime of the container returned by `get_vector()` has been extended to the lifetime of `v`.
+  }
+}

cpp/ql/src/Security/CWE/CWE-416/UseOfStringAfterLifetimeEnds.qhelp

@@ -8,6 +8,12 @@
 When the <code>std::string</code> object is destroyed, the pointer returned by <code>c_str</code> is no
 longer valid. If the pointer is used after the <code>std::string</code> object is destroyed, then the behavior is undefined.
 </p>
+
+<p>Typically, this problem occurs when a <code>std::string</code> is returned by a function call (or overloaded operator)
+by value, and the result is not immediately stored in a variable by value or reference in a way that extends the lifetime of
+the temporary object. The resulting temporary <code>std::string</code> object is destroyed at the end of the containing expression
+statement, along with any memory returned by a call to <code>c_str</code>.
+</p>
 </overview>
 
 <recommendation>
@@ -39,6 +45,8 @@ points to valid memory.
 <references>
 
 <li><a href="https://wiki.sei.cmu.edu/confluence/display/cplusplus/MEM50-CPP.+Do+not+access+freed+memory">MEM50-CPP. Do not access freed memory</a>.</li>
+<li>Microsoft Learn: <a href="https://learn.microsoft.com/en-us/cpp/cpp/temporary-objects?view=msvc-170">Temporary objects</a>.</li>
+<li>cppreference.com: <a href="https://en.cppreference.com/w/cpp/language/reference_initialization#Lifetime_of_a_temporary">Lifetime of a temporary</a>.</li>
 
 </references>
 </qhelp>

cpp/ql/src/Security/CWE/CWE-416/UseOfStringAfterLifetimeEnds.ql

@@ -23,4 +23,5 @@ where
   (c.getTarget() instanceof StdStringCStr or c.getTarget() instanceof StdStringData) and
   isTemporary(c.getQualifier().getFullyConverted())
 select c,
-  "The underlying string object is destroyed after the call to '" + c.getTarget() + "' returns."
+  "The underlying temporary string object is destroyed after the call to '" + c.getTarget() +
+    "' returns."

cpp/ql/src/Security/CWE/CWE-416/UseOfUniquePointerAfterLifetimeEnds.ql

@@ -30,6 +30,8 @@ where
   outlivesFullExpr(c) and
   not c.isFromUninstantiatedTemplate(_) and
   isUniquePointerDerefFunction(c.getTarget()) and
+  // Exclude cases where the pointer is implicitly converted to a non-pointer type
+  not c.getActualType() instanceof IntegralType and
   isTemporary(c.getQualifier().getFullyConverted())
 select c,
   "The underlying unique pointer object is destroyed after the call to '" + c.getTarget() +

cpp/ql/src/Security/CWE/CWE-676/DangerousFunctionOverflow.ql

@@ -17,5 +17,6 @@ import cpp
 from FunctionCall call, Function target
 where
   call.getTarget() = target and
-  target.hasGlobalOrStdName("gets")
+  target.hasGlobalOrStdName("gets") and
+  target.getNumberOfParameters() = 1
 select call, "'gets' does not guard against buffer overflow."