Use the js/ prefix for LdapInjection.ql

.codeqlmanifest.json

@@ -1,23 +1,11 @@
-{
-    "provide": [
-        "*/ql/src/qlpack.yml",
-        "*/ql/lib/qlpack.yml",
-        "*/ql/test/qlpack.yml",
-        "*/ql/examples/qlpack.yml",
-        "*/upgrades/qlpack.yml",
-        "cpp/ql/test/query-tests/Security/CWE/CWE-190/semmle/tainted/qlpack.yml",
-        "javascript/ql/experimental/adaptivethreatmodeling/lib/qlpack.yml",
-        "javascript/ql/experimental/adaptivethreatmodeling/src/qlpack.yml",
-        "misc/legacy-support/*/qlpack.yml",
-        "misc/suite-helpers/qlpack.yml",
-        "ruby/extractor-pack/codeql-extractor.yml",
-        "ruby/ql/consistency-queries/qlpack.yml"
-    ],
-    "versionPolicies": {
-      "default": {
-        "requireChangeNotes": true,
-        "committedPrereleaseSuffix": "dev",
-        "committedVersion": "nextPatchRelease"
-      }
-    }
-}
+{ "provide": [ "ruby/.codeqlmanifest.json",
+                "*/ql/src/qlpack.yml",
+               "*/ql/lib/qlpack.yml",
+               "*/ql/test/qlpack.yml",
+               "cpp/ql/test/query-tests/Security/CWE/CWE-190/semmle/tainted/qlpack.yml",
+               "*/ql/examples/qlpack.yml",
+               "*/upgrades/qlpack.yml",
+               "javascript/ql/experimental/adaptivethreatmodeling/lib/qlpack.yml",
+               "javascript/ql/experimental/adaptivethreatmodeling/src/qlpack.yml",
+               "misc/legacy-support/*/qlpack.yml",
+               "misc/suite-helpers/qlpack.yml" ] }

.github/actions/fetch-codeql/action.yml

@@ -8,7 +8,7 @@ runs:
       run: |
         LATEST=$(gh release list --repo https://github.com/github/codeql-cli-binaries | cut -f 1 | grep -v beta | sort --version-sort | tail -1)
         gh release download --repo https://github.com/github/codeql-cli-binaries --pattern codeql-linux64.zip "$LATEST"
-        unzip -q -d "${RUNNER_TEMP}" codeql-linux64.zip
-        echo "${RUNNER_TEMP}/codeql" >> "${GITHUB_PATH}"
+        unzip -q codeql-linux64.zip
+        echo "${{ github.workspace }}/codeql" >> $GITHUB_PATH
       env:
         GITHUB_TOKEN: ${{ github.token }}

.github/workflows/post-pr-comment.yml

@@ -1,31 +0,0 @@
-name: Post pull-request comment
-on:
-  workflow_run:
-    workflows: ["Query help preview"]
-    types:
-      - completed
-
-permissions:
-  pull-requests: write
-
-jobs:
-  post_comment:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Download artifact
-        run: gh run download "${WORKFLOW_RUN_ID}" --repo "${GITHUB_REPOSITORY}" --name "comment"
-        env:
-          GITHUB_TOKEN: ${{ github.token }}
-          WORKFLOW_RUN_ID: ${{ github.event.workflow_run.id }}
-      - run: |
-          PR="$(grep -o '^[0-9]\+$' pr.txt)"
-          PR_HEAD_SHA="$(gh api "/repos/${GITHUB_REPOSITORY}/pulls/${PR}" --jq .head.sha)"
-          # Check that the pull-request head SHA matches the head SHA of the workflow run
-          if [ "${WORKFLOW_RUN_HEAD_SHA}" != "${PR_HEAD_SHA}" ]; then
-            echo "PR head SHA ${PR_HEAD_SHA} does not match workflow_run event SHA ${WORKFLOW_RUN_HEAD_SHA}. Stopping." 1>&2
-            exit 1
-          fi
-          gh pr comment "${PR}" --repo "${GITHUB_REPOSITORY}" -F comment.txt
-        env:
-          GITHUB_TOKEN: ${{ github.token }}
-          WORKFLOW_RUN_HEAD_SHA: ${{ github.event.workflow_run.head_commit.id }}

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

@@ -1,13 +1,10 @@
 name: Query help preview
 
-permissions:
-  contents: read
-
 on:
   pull_request:
     branches:
       - main
-      - "rc/*"
+      - 'rc/*'
     paths:
       - "ruby/**/*.qhelp"
 
@@ -15,49 +12,28 @@ jobs:
   qhelp:
     runs-on: ubuntu-latest
     steps:
-      - run: echo "${{  github.event.number }}" > pr.txt
-      - uses: actions/upload-artifact@v2
-        with:
-          name: comment
-          path: pr.txt
-          retention-days: 1
       - uses: actions/checkout@v2
         with:
           fetch-depth: 2
-          persist-credentials: false
-      - uses: ./.github/actions/fetch-codeql
       - name: Determine changed files
         id: changes
         run: |
-          (git diff -z --name-only --diff-filter=ACMRT HEAD~1 HEAD | grep -z '.qhelp$' | grep -z -v '.inc.qhelp';
-           git diff -z --name-only --diff-filter=ACMRT HEAD~1 HEAD | grep -z '.inc.qhelp$' | xargs --null -rn1 basename | xargs --null -rn1 git grep -z -l) |
-           grep -z '.qhelp$' | grep -z -v '^-' | sort -z -u > "${RUNNER_TEMP}/paths.txt"
+          echo -n "::set-output name=qhelp_files::"
+          (git diff --name-only --diff-filter=ACMRT HEAD~1 HEAD | grep .qhelp$ | grep -v .inc.qhelp;
+           git diff --name-only --diff-filter=ACMRT HEAD~1 HEAD | grep .inc.qhelp$ | xargs -d '\n' -rn1 basename | xargs -d '\n' -rn1 git grep -l) |
+           sort -u | xargs -d '\n' -n1 printf "'%s' "
+
+      - uses: ./.github/actions/fetch-codeql
 
       - name: QHelp preview
+        if: ${{ steps.changes.outputs.qhelp_files }}
         run: |
-          EXIT_CODE=0
-          echo "QHelp previews:" > comment.txt
-          while read -r -d $'\0' path; do
-            if [ ! -f "${path}" ]; then
-               exit 1
-            fi
+          ( echo "QHelp previews:";
+          for path in ${{ steps.changes.outputs.qhelp_files }} ; do
             echo "<details> <summary>${path}</summary>"
             echo
-            codeql generate query-help --format=markdown -- "./${path}" 2> errors.txt || EXIT_CODE="$?"
-            if [ -s errors.txt ]; then
-               echo "# errors/warnings:"
-               echo '```'
-               cat errors.txt
-               cat errors.txt 1>&2
-               echo '```'
-            fi
+            codeql generate query-help --format=markdown ${path}
             echo "</details>"
-          done < "${RUNNER_TEMP}/paths.txt" >> comment.txt
-          exit "${EXIT_CODE}"
-
-      - if: always()
-        uses: actions/upload-artifact@v2
-        with:
-          name: comment
-          path: comment.txt
-          retention-days: 1
+          done) | gh pr comment "${{ github.event.pull_request.number }}" -F -
+        env:
+          GITHUB_TOKEN: ${{ github.token }}

.github/workflows/ruby-build.yml

@@ -3,18 +3,16 @@ name: "Ruby: Build"
 on:
   push:
     paths:
-      - "ruby/**"
-      - .github/workflows/ruby-build.yml
+      - 'ruby/**'
     branches:
       - main
-      - "rc/*"
+      - 'rc/*'
   pull_request:
     paths:
-      - "ruby/**"
-      - .github/workflows/ruby-build.yml
+      - 'ruby/**'
     branches:
       - main
-      - "rc/*"
+      - 'rc/*'
   workflow_dispatch:
     inputs:
       tag:
@@ -102,6 +100,16 @@ jobs:
           PACK_FOLDER=$(readlink -f target/packs/codeql/ruby-queries/*)
           codeql/codeql generate query-help --format=sarifv2.1.0 --output="${PACK_FOLDER}/rules.sarif" ql/src
           (cd ql/src; find queries \( -name '*.qhelp' -o -name '*.rb' -o -name '*.erb' \) -exec bash -c 'mkdir -p "'"${PACK_FOLDER}"'/$(dirname "{}")"' \; -exec cp "{}" "${PACK_FOLDER}/{}" \;)
+      - name: Compile with previous CodeQL versions
+        run: |
+          for version in  $(gh release list --repo https://github.com/github/codeql-cli-binaries | cut -f 1 | sort --version-sort | tail -3 | head -2); do
+            rm -f codeql-linux64.zip
+            gh release download --repo https://github.com/github/codeql-cli-binaries --pattern codeql-linux64.zip "$version"
+            rm -rf codeql; unzip -q codeql-linux64.zip
+            codeql/codeql query compile target/packs/*
+          done
+        env:
+          GITHUB_TOKEN: ${{ github.token }}
       - uses: actions/upload-artifact@v2
         with:
           name: codeql-ruby-queries

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

@@ -4,17 +4,15 @@ on:
   push:
     branches:
       - main
-      - "rc/*"
+      - 'rc/*'
     paths:
       - ruby/ql/lib/ruby.dbscheme
-      - .github/workflows/ruby-dataset-measure.yml
   pull_request:
     branches:
       - main
-      - "rc/*"
+      - 'rc/*'
     paths:
       - ruby/ql/lib/ruby.dbscheme
-      - .github/workflows/ruby-dataset-measure.yml
   workflow_dispatch:
 
 jobs:
@@ -24,7 +22,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        repo: [rails/rails, discourse/discourse, spree/spree, ruby/ruby]
+        repo: [rails/rails, discourse/discourse, spree/spree]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
@@ -41,7 +39,7 @@ jobs:
       - name: Create database
         run: |
           codeql database create \
-            --search-path "${{ github.workspace }}/ruby/extractor-pack" \
+            --search-path "${{ github.workspace }}/ruby" \
             --threads 4 \
             --language ruby --source-root "${{ github.workspace }}/repo" \
             "${{ runner.temp }}/database"

.github/workflows/ruby-qltest.yml

@@ -3,18 +3,16 @@ name: "Ruby: Run QL Tests"
 on:
   push:
     paths:
-      - "ruby/**"
-      - .github/workflows/ruby-qltest.yml
+      - 'ruby/**'
     branches:
       - main
-      - "rc/*"
+      - 'rc/*'
   pull_request:
     paths:
-      - "ruby/**"
-      - .github/workflows/ruby-qltest.yml
+      - 'ruby/**'
     branches:
       - main
-      - "rc/*"
+      - 'rc/*'
 
 env:
   CARGO_TERM_COLOR: always
@@ -32,19 +30,19 @@ jobs:
       - uses: ./ruby/actions/create-extractor-pack
       - name: Run QL tests
         run: |
-          codeql test run --search-path "${{ github.workspace }}/ruby/extractor-pack" --check-databases --check-unused-labels --check-repeated-labels --check-redefined-labels --check-use-before-definition --consistency-queries ql/consistency-queries ql/test
+          codeql test run --check-databases --check-unused-labels --check-repeated-labels --check-redefined-labels --check-use-before-definition --search-path "${{ github.workspace }}/ruby" --additional-packs "${{ github.workspace }}"  --consistency-queries ql/consistency-queries ql/test
         env:
           GITHUB_TOKEN: ${{ github.token }}
       - name: Check QL formatting
         run: find ql "(" -name "*.ql" -or -name "*.qll" ")" -print0 | xargs -0 codeql query format --check-only
       - name: Check QL compilation
         run: |
-          codeql query compile --check-only --threads=4 --warnings=error "ql/src" "ql/examples"
+          codeql query compile --check-only --threads=4 --warnings=error --search-path "${{ github.workspace }}/ruby" --additional-packs "${{ github.workspace }}" "ql/src" "ql/examples"
         env:
           GITHUB_TOKEN: ${{ github.token }}
       - name: Check DB upgrade scripts
         run: |
           echo >empty.trap
           codeql dataset import -S ql/lib/upgrades/initial/ruby.dbscheme testdb empty.trap
-          codeql dataset upgrade testdb --additional-packs ql/lib
+          codeql dataset upgrade testdb --additional-packs ql/lib/upgrades
           diff -q testdb/ruby.dbscheme ql/lib/ruby.dbscheme

.gitignore

@@ -27,6 +27,3 @@ csharp/extractor/Semmle.Extraction.CSharp.Driver/Properties/launchSettings.json
 
 # Avoid committing cached package components
 .codeql
-
-# Compiled class file
-*.class

config/identical-files.json

@@ -449,8 +449,7 @@
     "csharp/ql/lib/semmle/code/csharp/controlflow/internal/pressa/SsaImplCommon.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/basessa/SsaImplCommon.qll",
     "csharp/ql/lib/semmle/code/cil/internal/SsaImplCommon.qll",
-    "ruby/ql/lib/codeql/ruby/dataflow/internal/SsaImplCommon.qll",
-    "cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaImplCommon.qll"
+    "ruby/ql/lib/codeql/ruby/dataflow/internal/SsaImplCommon.qll"
   ],
   "CryptoAlgorithms Python/JS": [
     "javascript/ql/lib/semmle/javascript/security/CryptoAlgorithms.qll",
@@ -460,10 +459,9 @@
     "javascript/ql/lib/semmle/javascript/security/internal/SensitiveDataHeuristics.qll",
     "python/ql/lib/semmle/python/security/internal/SensitiveDataHeuristics.qll"
   ],
-  "ReDoS Util Python/JS/Ruby": [
+  "ReDoS Util Python/JS": [
     "javascript/ql/lib/semmle/javascript/security/performance/ReDoSUtil.qll",
-    "python/ql/lib/semmle/python/security/performance/ReDoSUtil.qll",
-    "ruby/ql/lib/codeql/ruby/security/performance/ReDoSUtil.qll"
+    "python/ql/lib/semmle/python/security/performance/ReDoSUtil.qll"
   ],
   "ReDoS Exponential Python/JS": [
     "javascript/ql/lib/semmle/javascript/security/performance/ExponentialBackTracking.qll",
@@ -472,12 +470,7 @@
   "ReDoS Polynomial Python/JS": [
     "javascript/ql/lib/semmle/javascript/security/performance/SuperlinearBackTracking.qll",
     "python/ql/lib/semmle/python/security/performance/SuperlinearBackTracking.qll",
-    "ruby/ql/lib/codeql/ruby/security/performance/SuperlinearBackTracking.qll"
-  ],
-  "BadTagFilterQuery Python/JS/Ruby": [
-    "javascript/ql/lib/semmle/javascript/security/BadTagFilterQuery.qll",
-    "python/ql/lib/semmle/python/security/BadTagFilterQuery.qll",
-    "ruby/ql/lib/codeql/ruby/security/BadTagFilterQuery.qll"
+    "ruby/ql/lib/codeql/ruby/regexp/SuperlinearBackTracking.qll"
   ],
   "CFG": [
     "csharp/ql/lib/semmle/code/csharp/controlflow/internal/ControlFlowGraphImplShared.qll",

cpp/change-notes/2021-11-01-isFromSystemMacroDefinition.md

@@ -1,7 +1,4 @@
-## 0.0.4
-
-### New Features
-
+lgtm,codescanning
 * The QL library `semmle.code.cpp.commons.Exclusions` now contains a predicate
   `isFromSystemMacroDefinition` for identifying code that originates from a
   macro outside the project being analyzed.

cpp/ql/lib/CHANGELOG.md

@@ -1,9 +0,0 @@
-## 0.0.5
-
-## 0.0.4
-
-### New Features
-
-* The QL library `semmle.code.cpp.commons.Exclusions` now contains a predicate
-  `isFromSystemMacroDefinition` for identifying code that originates from a
-  macro outside the project being analyzed.

cpp/ql/lib/change-notes/released/0.0.5.md

@@ -1 +0,0 @@
-## 0.0.5

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

@@ -1,2 +0,0 @@
----
-lastReleaseVersion: 0.0.5

cpp/ql/lib/qlpack.yml

@@ -1,8 +1,7 @@
 name: codeql/cpp-all
-version: 0.0.6-dev
-groups: cpp
+version: 0.0.2
 dbscheme: semmlecode.cpp.dbscheme
 extractor: cpp
 library: true
 dependencies:
-  codeql/cpp-upgrades: ^0.0.3
+  codeql/cpp-upgrades: 0.0.2

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

@@ -3,14 +3,11 @@ private import semmle.code.cpp.models.interfaces.ArrayFunction
 private import semmle.code.cpp.models.implementations.Strcat
 import semmle.code.cpp.dataflow.DataFlow
 
-/**
- * Holds if the expression `e` assigns something including `va` to a
- * stack variable `v0`.
- */
-private predicate mayAddNullTerminatorHelper(Expr e, VariableAccess va, StackVariable v0) {
-  exists(Expr val |
-    exprDefinition(v0, e, val) and // `e` is `v0 := val`
-    val.getAChild*() = va
+private predicate mayAddNullTerminatorHelper(Expr e, VariableAccess va, Expr e0) {
+  exists(StackVariable v0, Expr val |
+    exprDefinition(v0, e, val) and
+    val.getAChild*() = va and
+    mayAddNullTerminator(e0, v0.getAnAccess())
   )
 }
 
@@ -28,8 +25,8 @@ private predicate controlFlowNodeSuccessorTransitive(ControlFlowNode n1, Control
 }
 
 /**
- * Holds if the expression `e` may add a null terminator to the string
- * accessed by `va`.
+ * Holds if the expression `e` may add a null terminator to the string in
+ * variable `v`.
  */
 predicate mayAddNullTerminator(Expr e, VariableAccess va) {
   // Assignment: dereferencing or array access
@@ -46,9 +43,8 @@ predicate mayAddNullTerminator(Expr e, VariableAccess va) {
   )
   or
   // Assignment to another stack variable
-  exists(StackVariable v0, Expr e0 |
-    mayAddNullTerminatorHelper(e, va, v0) and
-    mayAddNullTerminator(pragma[only_bind_into](e0), pragma[only_bind_into](v0.getAnAccess())) and
+  exists(Expr e0 |
+    mayAddNullTerminatorHelper(pragma[only_bind_into](e), va, pragma[only_bind_into](e0)) and
     controlFlowNodeSuccessorTransitive(e, e0)
   )
   or

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

@@ -6,8 +6,6 @@ import semmle.code.cpp.Type
 import semmle.code.cpp.commons.CommonType
 import semmle.code.cpp.commons.StringAnalysis
 import semmle.code.cpp.models.interfaces.FormattingFunction
-private import semmle.code.cpp.rangeanalysis.SimpleRangeAnalysis
-private import semmle.code.cpp.rangeanalysis.RangeAnalysisUtils
 
 class PrintfFormatAttribute extends FormatAttribute {
   PrintfFormatAttribute() { this.getArchetype() = ["printf", "__printf__"] }
@@ -270,18 +268,6 @@ class FormattingFunctionCall extends Expr {
   }
 }
 
-/**
- * Gets the number of digits required to represent the integer represented by `f`.
- *
- * `f` is assumed to be nonnegative.
- */
-bindingset[f]
-private int lengthInBase10(float f) {
-  f = 0 and result = 1
-  or
-  result = f.log10().floor() + 1
-}
-
 /**
  * A class to represent format strings that occur as arguments to invocations of formatting functions.
  */
@@ -1060,63 +1046,39 @@ class FormatLiteral extends Literal {
         or
         this.getConversionChar(n).toLowerCase() = ["d", "i"] and
         // e.g. -2^31 = "-2147483648"
-        len =
-          min(float cand |
-            // The first case handles length sub-specifiers
-            // Subtract one in the exponent because one bit is for the sign.
-            // Add 1 to account for the possible sign in the output.
-            cand = 1 + lengthInBase10(2.pow(this.getIntegralDisplayType(n).getSize() * 8 - 1))
-            or
-            // The second case uses range analysis to deduce a length that's shorter than the length
-            // of the number -2^31.
-            exists(Expr arg, float lower, float upper |
-              arg = this.getUse().getConversionArgument(n) and
-              lower = lowerBound(arg.getFullyConverted()) and
-              upper = upperBound(arg.getFullyConverted())
-            |
-              cand =
-                max(int cand0 |
-                  // Include the sign bit in the length if it can be negative
-                  (
-                    if lower < 0
-                    then cand0 = 1 + lengthInBase10(lower.abs())
-                    else cand0 = lengthInBase10(lower)
-                  )
-                  or
-                  (
-                    if upper < 0
-                    then cand0 = 1 + lengthInBase10(upper.abs())
-                    else cand0 = lengthInBase10(upper)
-                  )
-                )
-            )
-          )
+        exists(int sizeBits |
+          sizeBits =
+            min(int bits |
+              bits = this.getIntegralDisplayType(n).getSize() * 8
+              or
+              exists(IntegralType t |
+                t = this.getUse().getConversionArgument(n).getType().getUnderlyingType()
+              |
+                t.isSigned() and bits = t.getSize() * 8
+              )
+            ) and
+          len = 1 + ((sizeBits - 1) / 10.0.log2()).ceil()
+          // this calculation is as %u (below) only we take out the sign bit (- 1) and allow a whole
+          // character for it to be expressed as '-'.
+        )
         or
         this.getConversionChar(n).toLowerCase() = "u" and
         // e.g. 2^32 - 1 = "4294967295"
-        len =
-          min(float cand |
-            // The first case handles length sub-specifiers
-            cand = 2.pow(this.getIntegralDisplayType(n).getSize() * 8)
-            or
-            // The second case uses range analysis to deduce a length that's shorter than
-            // the length of the number 2^31 - 1.
-            exists(Expr arg, float lower |
-              arg = this.getUse().getConversionArgument(n) and
-              lower = lowerBound(arg.getFullyConverted())
-            |
-              cand =
-                max(float cand0 |
-                  // If lower can be negative we use `(unsigned)-1` as the candidate value.
-                  lower < 0 and
-                  cand0 = 2.pow(any(IntType t | t.isUnsigned()).getSize() * 8)
-                  or
-                  cand0 = upperBound(arg.getFullyConverted())
-                )
-            )
-          |
-            lengthInBase10(cand)
-          )
+        exists(int sizeBits |
+          sizeBits =
+            min(int bits |
+              bits = this.getIntegralDisplayType(n).getSize() * 8
+              or
+              exists(IntegralType t |
+                t = this.getUse().getConversionArgument(n).getType().getUnderlyingType()
+              |
+                t.isUnsigned() and bits = t.getSize() * 8
+              )
+            ) and
+          len = (sizeBits / 10.0.log2()).ceil()
+          // convert the size from bits to decimal characters, and round up as you can't have
+          // fractional characters (10.0.log2() is the number of bits expressed per decimal character)
+        )
         or
         this.getConversionChar(n).toLowerCase() = "x" and
         // e.g. "12345678"

cpp/ql/lib/semmle/code/cpp/controlflow/internal/ConstantExprs.qll

@@ -626,9 +626,9 @@ library class ExprEvaluator extends int {
       // All assignments must have the same int value
       result =
         unique(Expr value |
-          value = v.getAnAssignedValue() and not this.ignoreVariableAssignment(e, v, value)
+          value = v.getAnAssignedValue() and not ignoreVariableAssignment(e, v, value)
         |
-          this.getValueInternalNonSubExpr(value)
+          getValueInternalNonSubExpr(value)
         )
     )
   }

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

@@ -1,6 +1,4 @@
 private import cpp
-private import semmle.code.cpp.dataflow.internal.DataFlowPrivate
-private import semmle.code.cpp.dataflow.internal.DataFlowUtil
 
 /**
  * Gets a function that might be called by `call`.
@@ -65,17 +63,3 @@ predicate mayBenefitFromCallContext(Call call, Function f) { none() }
  * restricted to those `call`s for which a context might make a difference.
  */
 Function viableImplInCallContext(Call call, Call ctx) { none() }
-
-/** A parameter position represented by an integer. */
-class ParameterPosition extends int {
-  ParameterPosition() { any(ParameterNode p).isParameterOf(_, this) }
-}
-
-/** An argument position represented by an integer. */
-class ArgumentPosition extends int {
-  ArgumentPosition() { any(ArgumentNode a).argumentOf(_, this) }
-}
-
-/** Holds if arguments at position `apos` match parameters at position `ppos`. */
-pragma[inline]
-predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) { ppos = apos }

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

@@ -2,42 +2,6 @@ private import DataFlowImplSpecific::Private
 private import DataFlowImplSpecific::Public
 import Cached
 
-module DataFlowImplCommonPublic {
-  private newtype TFlowFeature =
-    TFeatureHasSourceCallContext() or
-    TFeatureHasSinkCallContext() or
-    TFeatureEqualSourceSinkCallContext()
-
-  /** A flow configuration feature for use in `Configuration::getAFeature()`. */
-  class FlowFeature extends TFlowFeature {
-    string toString() { none() }
-  }
-
-  /**
-   * A flow configuration feature that implies that sources have some existing
-   * call context.
-   */
-  class FeatureHasSourceCallContext extends FlowFeature, TFeatureHasSourceCallContext {
-    override string toString() { result = "FeatureHasSourceCallContext" }
-  }
-
-  /**
-   * A flow configuration feature that implies that sinks have some existing
-   * call context.
-   */
-  class FeatureHasSinkCallContext extends FlowFeature, TFeatureHasSinkCallContext {
-    override string toString() { result = "FeatureHasSinkCallContext" }
-  }
-
-  /**
-   * A flow configuration feature that implies that source-sink pairs have some
-   * shared existing call context.
-   */
-  class FeatureEqualSourceSinkCallContext extends FlowFeature, TFeatureEqualSourceSinkCallContext {
-    override string toString() { result = "FeatureEqualSourceSinkCallContext" }
-  }
-}
-
 /**
  * The cost limits for the `AccessPathFront` to `AccessPathApprox` expansion.
  *
@@ -62,18 +26,6 @@ predicate accessPathCostLimits(int apLimit, int tupleLimit) {
   tupleLimit = 1000
 }
 
-/**
- * Holds if `arg` is an argument of `call` with an argument position that matches
- * parameter position `ppos`.
- */
-pragma[noinline]
-predicate argumentPositionMatch(DataFlowCall call, ArgNode arg, ParameterPosition ppos) {
-  exists(ArgumentPosition apos |
-    arg.argumentOf(call, apos) and
-    parameterMatch(ppos, apos)
-  )
-}
-
 /**
  * Provides a simple data-flow analysis for resolving lambda calls. The analysis
  * currently excludes read-steps, store-steps, and flow-through.
@@ -83,27 +35,25 @@ predicate argumentPositionMatch(DataFlowCall call, ArgNode arg, ParameterPositio
  * calls. For this reason, we cannot reuse the code from `DataFlowImpl.qll` directly.
  */
 private module LambdaFlow {
-  pragma[noinline]
-  private predicate viableParamNonLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
-    p.isParameterOf(viableCallable(call), ppos)
+  private predicate viableParamNonLambda(DataFlowCall call, int i, ParamNode p) {
+    p.isParameterOf(viableCallable(call), i)
   }
 
-  pragma[noinline]
-  private predicate viableParamLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
-    p.isParameterOf(viableCallableLambda(call, _), ppos)
+  private predicate viableParamLambda(DataFlowCall call, int i, ParamNode p) {
+    p.isParameterOf(viableCallableLambda(call, _), i)
   }
 
   private predicate viableParamArgNonLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(ParameterPosition ppos |
-      viableParamNonLambda(call, ppos, p) and
-      argumentPositionMatch(call, arg, ppos)
+    exists(int i |
+      viableParamNonLambda(call, i, p) and
+      arg.argumentOf(call, i)
     )
   }
 
   private predicate viableParamArgLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(ParameterPosition ppos |
-      viableParamLambda(call, ppos, p) and
-      argumentPositionMatch(call, arg, ppos)
+    exists(int i |
+      viableParamLambda(call, i, p) and
+      arg.argumentOf(call, i)
     )
   }
 
@@ -336,7 +286,7 @@ private module Cached {
     or
     exists(ArgNode arg |
       result.(PostUpdateNode).getPreUpdateNode() = arg and
-      arg.argumentOf(call, k.(ParamUpdateReturnKind).getAMatchingArgumentPosition())
+      arg.argumentOf(call, k.(ParamUpdateReturnKind).getPosition())
     )
   }
 
@@ -344,7 +294,7 @@ private module Cached {
   predicate returnNodeExt(Node n, ReturnKindExt k) {
     k = TValueReturn(n.(ReturnNode).getKind())
     or
-    exists(ParamNode p, ParameterPosition pos |
+    exists(ParamNode p, int pos |
       parameterValueFlowsToPreUpdate(p, n) and
       p.isParameterOf(_, pos) and
       k = TParamUpdate(pos)
@@ -366,13 +316,11 @@ private module Cached {
   }
 
   cached
-  predicate parameterNode(Node p, DataFlowCallable c, ParameterPosition pos) {
-    isParameterNode(p, c, pos)
-  }
+  predicate parameterNode(Node p, DataFlowCallable c, int pos) { isParameterNode(p, c, pos) }
 
   cached
-  predicate argumentNode(Node n, DataFlowCall call, ArgumentPosition pos) {
-    isArgumentNode(n, call, pos)
+  predicate argumentNode(Node n, DataFlowCall call, int pos) {
+    n.(ArgumentNode).argumentOf(call, pos)
   }
 
   /**
@@ -390,12 +338,12 @@ private module Cached {
   }
 
   /**
-   * Holds if `p` is the parameter of a viable dispatch target of `call`,
-   * and `p` has position `ppos`.
+   * Holds if `p` is the `i`th parameter of a viable dispatch target of `call`.
+   * The instance parameter is considered to have index `-1`.
    */
   pragma[nomagic]
-  private predicate viableParam(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
-    p.isParameterOf(viableCallableExt(call), ppos)
+  private predicate viableParam(DataFlowCall call, int i, ParamNode p) {
+    p.isParameterOf(viableCallableExt(call), i)
   }
 
   /**
@@ -404,9 +352,9 @@ private module Cached {
    */
   cached
   predicate viableParamArg(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(ParameterPosition ppos |
-      viableParam(call, ppos, p) and
-      argumentPositionMatch(call, arg, ppos) and
+    exists(int i |
+      viableParam(call, i, p) and
+      arg.argumentOf(call, i) and
       compatibleTypes(getNodeDataFlowType(arg), getNodeDataFlowType(p))
     )
   }
@@ -878,7 +826,7 @@ private module Cached {
   cached
   newtype TReturnKindExt =
     TValueReturn(ReturnKind kind) or
-    TParamUpdate(ParameterPosition pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
+    TParamUpdate(int pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
 
   cached
   newtype TBooleanOption =
@@ -1070,9 +1018,9 @@ class ParamNode extends Node {
 
   /**
    * Holds if this node is the parameter of callable `c` at the specified
-   * position.
+   * (zero-based) position.
    */
-  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) { parameterNode(this, c, pos) }
+  predicate isParameterOf(DataFlowCallable c, int i) { parameterNode(this, c, i) }
 }
 
 /** A data-flow node that represents a call argument. */
@@ -1080,9 +1028,7 @@ class ArgNode extends Node {
   ArgNode() { argumentNode(this, _, _) }
 
   /** Holds if this argument occurs at the given position in the given call. */
-  final predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
-    argumentNode(this, call, pos)
-  }
+  final predicate argumentOf(DataFlowCall call, int pos) { argumentNode(this, call, pos) }
 }
 
 /**
@@ -1128,14 +1074,11 @@ class ValueReturnKind extends ReturnKindExt, TValueReturn {
 }
 
 class ParamUpdateReturnKind extends ReturnKindExt, TParamUpdate {
-  private ParameterPosition pos;
+  private int pos;
 
   ParamUpdateReturnKind() { this = TParamUpdate(pos) }
 
-  ParameterPosition getPosition() { result = pos }
-
-  pragma[nomagic]
-  ArgumentPosition getAMatchingArgumentPosition() { parameterMatch(pos, result) }
+  int getPosition() { result = pos }
 
   override string toString() { result = "param update " + pos }
 }

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

@@ -9,19 +9,6 @@ private import tainttracking1.TaintTrackingParameter::Private
 private import tainttracking1.TaintTrackingParameter::Public
 
 module Consistency {
-  private newtype TConsistencyConfiguration = MkConsistencyConfiguration()
-
-  /** A class for configuring the consistency queries. */
-  class ConsistencyConfiguration extends TConsistencyConfiguration {
-    string toString() { none() }
-
-    /** Holds if `n` should be excluded from the consistency test `postWithInFlow`. */
-    predicate postWithInFlowExclude(Node n) { none() }
-
-    /** Holds if `n` should be excluded from the consistency test `argHasPostUpdate`. */
-    predicate argHasPostUpdateExclude(ArgumentNode n) { none() }
-  }
-
   private class RelevantNode extends Node {
     RelevantNode() {
       this instanceof ArgumentNode or
@@ -177,7 +164,7 @@ module Consistency {
 
   query predicate argHasPostUpdate(ArgumentNode n, string msg) {
     not hasPost(n) and
-    not any(ConsistencyConfiguration c).argHasPostUpdateExclude(n) and
+    not isImmutableOrUnobservable(n) and
     msg = "ArgumentNode is missing PostUpdateNode."
   }
 
@@ -190,7 +177,6 @@ module Consistency {
     isPostUpdateNode(n) and
     not clearsContent(n, _) and
     simpleLocalFlowStep(_, n) and
-    not any(ConsistencyConfiguration c).postWithInFlowExclude(n) and
     msg = "PostUpdateNode should not be the target of local flow."
   }
 }

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

@@ -2,20 +2,12 @@ private import cpp
 private import DataFlowUtil
 private import DataFlowDispatch
 private import FlowVar
-private import DataFlowImplConsistency
 
 /** Gets the callable in which this node occurs. */
 DataFlowCallable nodeGetEnclosingCallable(Node n) { result = n.getEnclosingCallable() }
 
 /** Holds if `p` is a `ParameterNode` of `c` with position `pos`. */
-predicate isParameterNode(ParameterNode p, DataFlowCallable c, ParameterPosition pos) {
-  p.isParameterOf(c, pos)
-}
-
-/** Holds if `arg` is an `ArgumentNode` of `c` with position `pos`. */
-predicate isArgumentNode(ArgumentNode arg, DataFlowCall c, ArgumentPosition pos) {
-  arg.argumentOf(c, pos)
-}
+predicate isParameterNode(ParameterNode p, DataFlowCallable c, int pos) { p.isParameterOf(c, pos) }
 
 /** Gets the instance argument of a non-static call. */
 private Node getInstanceArgument(Call call) {
@@ -267,6 +259,27 @@ class Unit extends TUnit {
   string toString() { result = "unit" }
 }
 
+/**
+ * Holds if `n` does not require a `PostUpdateNode` as it either cannot be
+ * modified or its modification cannot be observed, for example if it is a
+ * freshly created object that is not saved in a variable.
+ *
+ * This predicate is only used for consistency checks.
+ */
+predicate isImmutableOrUnobservable(Node n) {
+  // Is the null pointer (or something that's not really a pointer)
+  exists(n.asExpr().getValue())
+  or
+  // Isn't a pointer or is a pointer to const
+  forall(DerivedType dt | dt = n.asExpr().getActualType() |
+    dt.getBaseType().isConst()
+    or
+    dt.getBaseType() instanceof RoutineType
+  )
+  // The above list of cases isn't exhaustive, but it narrows down the
+  // consistency alerts enough that most of them are interesting.
+}
+
 /** Holds if `n` should be hidden from path explanations. */
 predicate nodeIsHidden(Node n) { none() }
 
@@ -289,19 +302,3 @@ predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preserves
  * by default as a heuristic.
  */
 predicate allowParameterReturnInSelf(ParameterNode p) { none() }
-
-private class MyConsistencyConfiguration extends Consistency::ConsistencyConfiguration {
-  override predicate argHasPostUpdateExclude(ArgumentNode n) {
-    // Is the null pointer (or something that's not really a pointer)
-    exists(n.asExpr().getValue())
-    or
-    // Isn't a pointer or is a pointer to const
-    forall(DerivedType dt | dt = n.asExpr().getActualType() |
-      dt.getBaseType().isConst()
-      or
-      dt.getBaseType() instanceof RoutineType
-    )
-    // The above list of cases isn't exhaustive, but it narrows down the
-    // consistency alerts enough that most of them are interesting.
-  }
-}

cpp/ql/lib/semmle/code/cpp/ir/dataflow/DefaultTaintTracking.qll

@@ -474,25 +474,6 @@ module TaintedWithPath {
     }
   }
 
-  /**
-   * INTERNAL: Do not use.
-   */
-  module Private {
-    /** Gets a predecessor `PathNode` of `pathNode`, if any. */
-    PathNode getAPredecessor(PathNode pathNode) { edges(result, pathNode) }
-
-    /** Gets the element that `pathNode` wraps, if any. */
-    Element getElementFromPathNode(PathNode pathNode) {
-      exists(DataFlow::Node node | node = pathNode.(WrapPathNode).inner().getNode() |
-        result = node.asInstruction().getAST()
-        or
-        result = node.asOperand().getDef().getAST()
-      )
-      or
-      result = pathNode.(EndpointPathNode).inner()
-    }
-  }
-
   private class WrapPathNode extends PathNode, TWrapPathNode {
     DataFlow3::PathNode inner() { this = TWrapPathNode(result) }
 

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

@@ -2,7 +2,6 @@ private import cpp
 private import semmle.code.cpp.ir.IR
 private import semmle.code.cpp.ir.dataflow.DataFlow
 private import semmle.code.cpp.ir.dataflow.internal.DataFlowPrivate
-private import semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
 private import DataFlowImplCommon as DataFlowImplCommon
 
 /**
@@ -64,10 +63,8 @@ private module VirtualDispatch {
       |
         // Call argument
         exists(DataFlowCall call, int i |
-          other
-              .(DataFlow::ParameterNode)
-              .isParameterOf(pragma[only_bind_into](call).getStaticCallTarget(), i) and
-          src.(ArgumentNode).argumentOf(call, pragma[only_bind_into](pragma[only_bind_out](i)))
+          other.(DataFlow::ParameterNode).isParameterOf(call.getStaticCallTarget(), i) and
+          src.(ArgumentNode).argumentOf(call, i)
         ) and
         allowOtherFromArg = true and
         allowFromArg = true
@@ -131,7 +128,6 @@ private module VirtualDispatch {
    *
    * Used to fix a join ordering issue in flowsFrom.
    */
-  pragma[noinline]
   private predicate returnNodeWithKindAndEnclosingCallable(
     ReturnNode node, ReturnKind kind, DataFlowCallable callable
   ) {
@@ -267,17 +263,3 @@ Function viableImplInCallContext(CallInstruction call, CallInstruction ctx) {
     result = ctx.getArgument(i).getUnconvertedResultExpression().(FunctionAccess).getTarget()
   )
 }
-
-/** A parameter position represented by an integer. */
-class ParameterPosition extends int {
-  ParameterPosition() { any(ParameterNode p).isParameterOf(_, this) }
-}
-
-/** An argument position represented by an integer. */
-class ArgumentPosition extends int {
-  ArgumentPosition() { any(ArgumentNode a).argumentOf(_, this) }
-}
-
-/** Holds if arguments at position `apos` match parameters at position `ppos`. */
-pragma[inline]
-predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) { ppos = apos }

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

@@ -2,42 +2,6 @@ private import DataFlowImplSpecific::Private
 private import DataFlowImplSpecific::Public
 import Cached
 
-module DataFlowImplCommonPublic {
-  private newtype TFlowFeature =
-    TFeatureHasSourceCallContext() or
-    TFeatureHasSinkCallContext() or
-    TFeatureEqualSourceSinkCallContext()
-
-  /** A flow configuration feature for use in `Configuration::getAFeature()`. */
-  class FlowFeature extends TFlowFeature {
-    string toString() { none() }
-  }
-
-  /**
-   * A flow configuration feature that implies that sources have some existing
-   * call context.
-   */
-  class FeatureHasSourceCallContext extends FlowFeature, TFeatureHasSourceCallContext {
-    override string toString() { result = "FeatureHasSourceCallContext" }
-  }
-
-  /**
-   * A flow configuration feature that implies that sinks have some existing
-   * call context.
-   */
-  class FeatureHasSinkCallContext extends FlowFeature, TFeatureHasSinkCallContext {
-    override string toString() { result = "FeatureHasSinkCallContext" }
-  }
-
-  /**
-   * A flow configuration feature that implies that source-sink pairs have some
-   * shared existing call context.
-   */
-  class FeatureEqualSourceSinkCallContext extends FlowFeature, TFeatureEqualSourceSinkCallContext {
-    override string toString() { result = "FeatureEqualSourceSinkCallContext" }
-  }
-}
-
 /**
  * The cost limits for the `AccessPathFront` to `AccessPathApprox` expansion.
  *
@@ -62,18 +26,6 @@ predicate accessPathCostLimits(int apLimit, int tupleLimit) {
   tupleLimit = 1000
 }
 
-/**
- * Holds if `arg` is an argument of `call` with an argument position that matches
- * parameter position `ppos`.
- */
-pragma[noinline]
-predicate argumentPositionMatch(DataFlowCall call, ArgNode arg, ParameterPosition ppos) {
-  exists(ArgumentPosition apos |
-    arg.argumentOf(call, apos) and
-    parameterMatch(ppos, apos)
-  )
-}
-
 /**
  * Provides a simple data-flow analysis for resolving lambda calls. The analysis
  * currently excludes read-steps, store-steps, and flow-through.
@@ -83,27 +35,25 @@ predicate argumentPositionMatch(DataFlowCall call, ArgNode arg, ParameterPositio
  * calls. For this reason, we cannot reuse the code from `DataFlowImpl.qll` directly.
  */
 private module LambdaFlow {
-  pragma[noinline]
-  private predicate viableParamNonLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
-    p.isParameterOf(viableCallable(call), ppos)
+  private predicate viableParamNonLambda(DataFlowCall call, int i, ParamNode p) {
+    p.isParameterOf(viableCallable(call), i)
   }
 
-  pragma[noinline]
-  private predicate viableParamLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
-    p.isParameterOf(viableCallableLambda(call, _), ppos)
+  private predicate viableParamLambda(DataFlowCall call, int i, ParamNode p) {
+    p.isParameterOf(viableCallableLambda(call, _), i)
   }
 
   private predicate viableParamArgNonLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(ParameterPosition ppos |
-      viableParamNonLambda(call, ppos, p) and
-      argumentPositionMatch(call, arg, ppos)
+    exists(int i |
+      viableParamNonLambda(call, i, p) and
+      arg.argumentOf(call, i)
     )
   }
 
   private predicate viableParamArgLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(ParameterPosition ppos |
-      viableParamLambda(call, ppos, p) and
-      argumentPositionMatch(call, arg, ppos)
+    exists(int i |
+      viableParamLambda(call, i, p) and
+      arg.argumentOf(call, i)
     )
   }
 
@@ -336,7 +286,7 @@ private module Cached {
     or
     exists(ArgNode arg |
       result.(PostUpdateNode).getPreUpdateNode() = arg and
-      arg.argumentOf(call, k.(ParamUpdateReturnKind).getAMatchingArgumentPosition())
+      arg.argumentOf(call, k.(ParamUpdateReturnKind).getPosition())
     )
   }
 
@@ -344,7 +294,7 @@ private module Cached {
   predicate returnNodeExt(Node n, ReturnKindExt k) {
     k = TValueReturn(n.(ReturnNode).getKind())
     or
-    exists(ParamNode p, ParameterPosition pos |
+    exists(ParamNode p, int pos |
       parameterValueFlowsToPreUpdate(p, n) and
       p.isParameterOf(_, pos) and
       k = TParamUpdate(pos)
@@ -366,13 +316,11 @@ private module Cached {
   }
 
   cached
-  predicate parameterNode(Node p, DataFlowCallable c, ParameterPosition pos) {
-    isParameterNode(p, c, pos)
-  }
+  predicate parameterNode(Node p, DataFlowCallable c, int pos) { isParameterNode(p, c, pos) }
 
   cached
-  predicate argumentNode(Node n, DataFlowCall call, ArgumentPosition pos) {
-    isArgumentNode(n, call, pos)
+  predicate argumentNode(Node n, DataFlowCall call, int pos) {
+    n.(ArgumentNode).argumentOf(call, pos)
   }
 
   /**
@@ -390,12 +338,12 @@ private module Cached {
   }
 
   /**
-   * Holds if `p` is the parameter of a viable dispatch target of `call`,
-   * and `p` has position `ppos`.
+   * Holds if `p` is the `i`th parameter of a viable dispatch target of `call`.
+   * The instance parameter is considered to have index `-1`.
    */
   pragma[nomagic]
-  private predicate viableParam(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
-    p.isParameterOf(viableCallableExt(call), ppos)
+  private predicate viableParam(DataFlowCall call, int i, ParamNode p) {
+    p.isParameterOf(viableCallableExt(call), i)
   }
 
   /**
@@ -404,9 +352,9 @@ private module Cached {
    */
   cached
   predicate viableParamArg(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(ParameterPosition ppos |
-      viableParam(call, ppos, p) and
-      argumentPositionMatch(call, arg, ppos) and
+    exists(int i |
+      viableParam(call, i, p) and
+      arg.argumentOf(call, i) and
       compatibleTypes(getNodeDataFlowType(arg), getNodeDataFlowType(p))
     )
   }
@@ -878,7 +826,7 @@ private module Cached {
   cached
   newtype TReturnKindExt =
     TValueReturn(ReturnKind kind) or
-    TParamUpdate(ParameterPosition pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
+    TParamUpdate(int pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
 
   cached
   newtype TBooleanOption =
@@ -1070,9 +1018,9 @@ class ParamNode extends Node {
 
   /**
    * Holds if this node is the parameter of callable `c` at the specified
-   * position.
+   * (zero-based) position.
    */
-  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) { parameterNode(this, c, pos) }
+  predicate isParameterOf(DataFlowCallable c, int i) { parameterNode(this, c, i) }
 }
 
 /** A data-flow node that represents a call argument. */
@@ -1080,9 +1028,7 @@ class ArgNode extends Node {
   ArgNode() { argumentNode(this, _, _) }
 
   /** Holds if this argument occurs at the given position in the given call. */
-  final predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
-    argumentNode(this, call, pos)
-  }
+  final predicate argumentOf(DataFlowCall call, int pos) { argumentNode(this, call, pos) }
 }
 
 /**
@@ -1128,14 +1074,11 @@ class ValueReturnKind extends ReturnKindExt, TValueReturn {
 }
 
 class ParamUpdateReturnKind extends ReturnKindExt, TParamUpdate {
-  private ParameterPosition pos;
+  private int pos;
 
   ParamUpdateReturnKind() { this = TParamUpdate(pos) }
 
-  ParameterPosition getPosition() { result = pos }
-
-  pragma[nomagic]
-  ArgumentPosition getAMatchingArgumentPosition() { parameterMatch(pos, result) }
+  int getPosition() { result = pos }
 
   override string toString() { result = "param update " + pos }
 }

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

@@ -9,19 +9,6 @@ private import tainttracking1.TaintTrackingParameter::Private
 private import tainttracking1.TaintTrackingParameter::Public
 
 module Consistency {
-  private newtype TConsistencyConfiguration = MkConsistencyConfiguration()
-
-  /** A class for configuring the consistency queries. */
-  class ConsistencyConfiguration extends TConsistencyConfiguration {
-    string toString() { none() }
-
-    /** Holds if `n` should be excluded from the consistency test `postWithInFlow`. */
-    predicate postWithInFlowExclude(Node n) { none() }
-
-    /** Holds if `n` should be excluded from the consistency test `argHasPostUpdate`. */
-    predicate argHasPostUpdateExclude(ArgumentNode n) { none() }
-  }
-
   private class RelevantNode extends Node {
     RelevantNode() {
       this instanceof ArgumentNode or
@@ -177,7 +164,7 @@ module Consistency {
 
   query predicate argHasPostUpdate(ArgumentNode n, string msg) {
     not hasPost(n) and
-    not any(ConsistencyConfiguration c).argHasPostUpdateExclude(n) and
+    not isImmutableOrUnobservable(n) and
     msg = "ArgumentNode is missing PostUpdateNode."
   }
 
@@ -190,7 +177,6 @@ module Consistency {
     isPostUpdateNode(n) and
     not clearsContent(n, _) and
     simpleLocalFlowStep(_, n) and
-    not any(ConsistencyConfiguration c).postWithInFlowExclude(n) and
     msg = "PostUpdateNode should not be the target of local flow."
   }
 }

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

@@ -2,20 +2,12 @@ private import cpp
 private import DataFlowUtil
 private import semmle.code.cpp.ir.IR
 private import DataFlowDispatch
-private import DataFlowImplConsistency
 
 /** Gets the callable in which this node occurs. */
 DataFlowCallable nodeGetEnclosingCallable(Node n) { result = n.getEnclosingCallable() }
 
 /** Holds if `p` is a `ParameterNode` of `c` with position `pos`. */
-predicate isParameterNode(ParameterNode p, DataFlowCallable c, ParameterPosition pos) {
-  p.isParameterOf(c, pos)
-}
-
-/** Holds if `arg` is an `ArgumentNode` of `c` with position `pos`. */
-predicate isArgumentNode(ArgumentNode arg, DataFlowCall c, ArgumentPosition pos) {
-  arg.argumentOf(c, pos)
-}
+predicate isParameterNode(ParameterNode p, DataFlowCallable c, int pos) { p.isParameterOf(c, pos) }
 
 /**
  * A data flow node that occurs as the argument of a call and is passed as-is
@@ -120,9 +112,11 @@ class ReturnNode extends InstructionNode {
   Instruction primary;
 
   ReturnNode() {
-    exists(ReturnValueInstruction ret | instr = ret and primary = ret)
+    exists(ReturnValueInstruction ret | instr = ret.getReturnValue() and primary = ret)
     or
-    exists(ReturnIndirectionInstruction rii | instr = rii and primary = rii)
+    exists(ReturnIndirectionInstruction rii |
+      instr = rii.getSideEffectOperand().getAnyDef() and primary = rii
+    )
   }
 
   /** Gets the kind of this returned value. */
@@ -196,16 +190,108 @@ OutNode getAnOutNode(DataFlowCall call, ReturnKind kind) {
  */
 predicate jumpStep(Node n1, Node n2) { none() }
 
+private predicate fieldStoreStepNoChi(Node node1, FieldContent f, PostUpdateNode node2) {
+  exists(StoreInstruction store, Class c |
+    store = node2.asInstruction() and
+    store.getSourceValueOperand() = node1.asOperand() and
+    getWrittenField(store, f.getAField(), c) and
+    f.hasOffset(c, _, _)
+  )
+}
+
+private FieldAddressInstruction getFieldInstruction(Instruction instr) {
+  result = instr or
+  result = instr.(CopyValueInstruction).getUnary()
+}
+
+pragma[noinline]
+private predicate getWrittenField(Instruction instr, Field f, Class c) {
+  exists(FieldAddressInstruction fa |
+    fa =
+      getFieldInstruction([
+          instr.(StoreInstruction).getDestinationAddress(),
+          instr.(WriteSideEffectInstruction).getDestinationAddress()
+        ]) and
+    f = fa.getField() and
+    c = f.getDeclaringType()
+  )
+}
+
+private predicate fieldStoreStepChi(Node node1, FieldContent f, PostUpdateNode node2) {
+  exists(ChiPartialOperand operand, ChiInstruction chi |
+    chi.getPartialOperand() = operand and
+    node1.asOperand() = operand and
+    node2.asInstruction() = chi and
+    exists(Class c |
+      c = chi.getResultType() and
+      exists(int startBit, int endBit |
+        chi.getUpdatedInterval(startBit, endBit) and
+        f.hasOffset(c, startBit, endBit)
+      )
+      or
+      getWrittenField(operand.getDef(), f.getAField(), c) and
+      f.hasOffset(c, _, _)
+    )
+  )
+}
+
+private predicate arrayStoreStepChi(Node node1, ArrayContent a, PostUpdateNode node2) {
+  exists(a) and
+  exists(ChiPartialOperand operand, ChiInstruction chi, StoreInstruction store |
+    chi.getPartialOperand() = operand and
+    store = operand.getDef() and
+    node1.asOperand() = operand and
+    // This `ChiInstruction` will always have a non-conflated result because both `ArrayStoreNode`
+    // and `PointerStoreNode` require it in their characteristic predicates.
+    node2.asInstruction() = chi and
+    (
+      // `x[i] = taint()`
+      // This matches the characteristic predicate in `ArrayStoreNode`.
+      store.getDestinationAddress() instanceof PointerAddInstruction
+      or
+      // `*p = taint()`
+      // This matches the characteristic predicate in `PointerStoreNode`.
+      store.getDestinationAddress().(CopyValueInstruction).getUnary() instanceof LoadInstruction
+    )
+  )
+}
+
 /**
  * Holds if data can flow from `node1` to `node2` via an assignment to `f`.
  * Thus, `node2` references an object with a field `f` that contains the
  * value of `node1`.
  */
-predicate storeStep(StoreNodeInstr node1, FieldContent f, StoreNodeInstr node2) {
-  exists(FieldAddressInstruction fai |
-    node1.getInstruction() = fai and
-    node2.getInstruction() = fai.getObjectAddress() and
-    f.getField() = fai.getField()
+predicate storeStep(Node node1, Content f, PostUpdateNode node2) {
+  fieldStoreStepNoChi(node1, f, node2) or
+  fieldStoreStepChi(node1, f, node2) or
+  arrayStoreStepChi(node1, f, node2) or
+  fieldStoreStepAfterArraySuppression(node1, f, node2)
+}
+
+// This predicate pushes the correct `FieldContent` onto the access path when the
+// `suppressArrayRead` predicate has popped off an `ArrayContent`.
+private predicate fieldStoreStepAfterArraySuppression(
+  Node node1, FieldContent f, PostUpdateNode node2
+) {
+  exists(WriteSideEffectInstruction write, ChiInstruction chi, Class c |
+    not chi.isResultConflated() and
+    node1.asInstruction() = chi and
+    node2.asInstruction() = chi and
+    chi.getPartial() = write and
+    getWrittenField(write, f.getAField(), c) and
+    f.hasOffset(c, _, _)
+  )
+}
+
+bindingset[result, i]
+private int unbindInt(int i) { i <= result and i >= result }
+
+pragma[noinline]
+private predicate getLoadedField(LoadInstruction load, Field f, Class c) {
+  exists(FieldAddressInstruction fa |
+    fa = load.getSourceAddress() and
+    f = fa.getField() and
+    c = f.getDeclaringType()
   )
 }
 
@@ -214,14 +300,122 @@ predicate storeStep(StoreNodeInstr node1, FieldContent f, StoreNodeInstr node2)
  * Thus, `node1` references an object with a field `f` whose value ends up in
  * `node2`.
  */
-predicate readStep(ReadNode node1, FieldContent f, ReadNode node2) {
-  exists(FieldAddressInstruction fai |
-    node1.getInstruction() = fai.getObjectAddress() and
-    node2.getInstruction() = fai and
-    f.getField() = fai.getField()
+private predicate fieldReadStep(Node node1, FieldContent f, Node node2) {
+  exists(LoadOperand operand |
+    node2.asOperand() = operand and
+    node1.asInstruction() = operand.getAnyDef() and
+    exists(Class c |
+      c = operand.getAnyDef().getResultType() and
+      exists(int startBit, int endBit |
+        operand.getUsedInterval(unbindInt(startBit), unbindInt(endBit)) and
+        f.hasOffset(c, startBit, endBit)
+      )
+      or
+      getLoadedField(operand.getUse(), f.getAField(), c) and
+      f.hasOffset(c, _, _)
+    )
   )
 }
 
+/**
+ * When a store step happens in a function that looks like an array write such as:
+ * ```cpp
+ * void f(int* pa) {
+ *   pa = source();
+ * }
+ * ```
+ * it can be a write to an array, but it can also happen that `f` is called as `f(&a.x)`. If that is
+ * the case, the `ArrayContent` that was written by the call to `f` should be popped off the access
+ * path, and a `FieldContent` containing `x` should be pushed instead.
+ * So this case pops `ArrayContent` off the access path, and the `fieldStoreStepAfterArraySuppression`
+ * predicate in `storeStep` ensures that we push the right `FieldContent` onto the access path.
+ */
+predicate suppressArrayRead(Node node1, ArrayContent a, Node node2) {
+  exists(a) and
+  exists(WriteSideEffectInstruction write, ChiInstruction chi |
+    node1.asInstruction() = write and
+    node2.asInstruction() = chi and
+    chi.getPartial() = write and
+    getWrittenField(write, _, _)
+  )
+}
+
+private class ArrayToPointerConvertInstruction extends ConvertInstruction {
+  ArrayToPointerConvertInstruction() {
+    this.getUnary().getResultType() instanceof ArrayType and
+    this.getResultType() instanceof PointerType
+  }
+}
+
+private Instruction skipOneCopyValueInstructionRec(CopyValueInstruction copy) {
+  copy.getUnary() = result and not result instanceof CopyValueInstruction
+  or
+  result = skipOneCopyValueInstructionRec(copy.getUnary())
+}
+
+private Instruction skipCopyValueInstructions(Operand op) {
+  not result instanceof CopyValueInstruction and result = op.getDef()
+  or
+  result = skipOneCopyValueInstructionRec(op.getDef())
+}
+
+private predicate arrayReadStep(Node node1, ArrayContent a, Node node2) {
+  exists(a) and
+  // Explicit dereferences such as `*p` or `p[i]` where `p` is a pointer or array.
+  exists(LoadOperand operand, Instruction address |
+    operand.isDefinitionInexact() and
+    node1.asInstruction() = operand.getAnyDef() and
+    operand = node2.asOperand() and
+    address = skipCopyValueInstructions(operand.getAddressOperand()) and
+    (
+      address instanceof LoadInstruction or
+      address instanceof ArrayToPointerConvertInstruction or
+      address instanceof PointerOffsetInstruction
+    )
+  )
+}
+
+/**
+ * In cases such as:
+ * ```cpp
+ * void f(int* pa) {
+ *   *pa = source();
+ * }
+ * ...
+ * int x;
+ * f(&x);
+ * use(x);
+ * ```
+ * the load on `x` in `use(x)` will exactly overlap with its definition (in this case the definition
+ * is a `WriteSideEffect`). This predicate pops the `ArrayContent` (pushed by the store in `f`)
+ * from the access path.
+ */
+private predicate exactReadStep(Node node1, ArrayContent a, Node node2) {
+  exists(a) and
+  exists(WriteSideEffectInstruction write, ChiInstruction chi |
+    not chi.isResultConflated() and
+    chi.getPartial() = write and
+    node1.asInstruction() = write and
+    node2.asInstruction() = chi and
+    // To distinquish this case from the `arrayReadStep` case we require that the entire variable was
+    // overwritten by the `WriteSideEffectInstruction` (i.e., there is a load that reads the
+    // entire variable).
+    exists(LoadInstruction load | load.getSourceValue() = chi)
+  )
+}
+
+/**
+ * Holds if data can flow from `node1` to `node2` via a read of `f`.
+ * Thus, `node1` references an object with a field `f` whose value ends up in
+ * `node2`.
+ */
+predicate readStep(Node node1, Content f, Node node2) {
+  fieldReadStep(node1, f, node2) or
+  arrayReadStep(node1, f, node2) or
+  exactReadStep(node1, f, node2) or
+  suppressArrayRead(node1, f, node2)
+}
+
 /**
  * Holds if values stored inside content `c` are cleared at node `n`.
  */
@@ -253,7 +447,7 @@ private predicate suppressUnusedNode(Node n) { any() }
 // Java QL library compatibility wrappers
 //////////////////////////////////////////////////////////////////////////////
 /** A node that performs a type cast. */
-class CastNode extends Node {
+class CastNode extends InstructionNode {
   CastNode() { none() } // stub implementation
 }
 
@@ -293,19 +487,22 @@ class Unit extends TUnit {
   string toString() { result = "unit" }
 }
 
-/** Holds if `n` should be hidden from path explanations. */
-predicate nodeIsHidden(Node n) {
-  n instanceof OperandNode and not n instanceof ArgumentNode
-  or
-  StoreNodeFlow::flowThrough(n, _) and
-  not StoreNodeFlow::flowOutOf(n, _) and
-  not StoreNodeFlow::flowInto(_, n)
-  or
-  ReadNodeFlow::flowThrough(n, _) and
-  not ReadNodeFlow::flowOutOf(n, _) and
-  not ReadNodeFlow::flowInto(_, n)
+/**
+ * Holds if `n` does not require a `PostUpdateNode` as it either cannot be
+ * modified or its modification cannot be observed, for example if it is a
+ * freshly created object that is not saved in a variable.
+ *
+ * This predicate is only used for consistency checks.
+ */
+predicate isImmutableOrUnobservable(Node n) {
+  // The rules for whether an IR argument gets a post-update node are too
+  // complex to model here.
+  any()
 }
 
+/** Holds if `n` should be hidden from path explanations. */
+predicate nodeIsHidden(Node n) { n instanceof OperandNode and not n instanceof ArgumentNode }
+
 class LambdaCallKind = Unit;
 
 /** Holds if `creation` is an expression that creates a lambda of kind `kind` for `c`. */
@@ -325,11 +522,3 @@ predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preserves
  * by default as a heuristic.
  */
 predicate allowParameterReturnInSelf(ParameterNode p) { none() }
-
-private class MyConsistencyConfiguration extends Consistency::ConsistencyConfiguration {
-  override predicate argHasPostUpdateExclude(ArgumentNode n) {
-    // The rules for whether an IR argument gets a post-update node are too
-    // complex to model here.
-    any()
-  }
-}

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

@@ -10,78 +10,19 @@ private import semmle.code.cpp.ir.ValueNumbering
 private import semmle.code.cpp.ir.IR
 private import semmle.code.cpp.controlflow.IRGuards
 private import semmle.code.cpp.models.interfaces.DataFlow
-private import DataFlowPrivate
-private import SsaInternals as Ssa
 
 cached
 private module Cached {
-  /**
-   * The IR dataflow graph consists of the following nodes:
-   * - `InstructionNode`, which represents an `Instruction` in the graph.
-   * - `OperandNode`, which represents an `Operand` in the graph.
-   * - `VariableNode`, which is used to model global variables.
-   * - Two kinds of `StoreNode`s:
-   *   1. `StoreNodeInstr`, which represents the value of an address computed by an `Instruction` that
-   *      has been updated by a write operation.
-   *   2. `StoreNodeOperand`, which represents the value of an address in an `ArgumentOperand` after a
-   *      function call that may have changed the value.
-   * - `ReadNode`, which represents the result of reading a field of an object.
-   * - `SsaPhiNode`, which represents phi nodes as computed by the shared SSA library.
-   *
-   * The following section describes how flow is generally transferred between these nodes:
-   * - Flow between `InstructionNode`s and `OperandNode`s follow the def-use information as computed by
-   *   the IR. Because the IR compute must-alias information for memory operands, we only follow def-use
-   *   flow for register operands.
-   * - Flow can enter a `StoreNode` in two ways (both done in `StoreNode.flowInto`):
-   *   1. Flow is transferred from a `StoreValueOperand` to a `StoreNodeInstr`. Flow will then proceed
-   *      along the chain of addresses computed by `StoreNodeInstr.getInner` to identify field writes
-   *      and call `storeStep` accordingly (i.e., for an expression like `a.b.c = x`, we visit `c`, then
-   *      `b`, then `a`).
-   *   2. Flow is transfered from a `WriteSideEffectInstruction` to a `StoreNodeOperand` after flow
-   *      returns to a caller. Flow will then proceed to the defining instruction of the operand (because
-   *      the `StoreNodeInstr` computed by `StoreNodeOperand.getInner()` is the `StoreNode` containing
-   *      the defining instruction), and then along the chain computed by `StoreNodeInstr.getInner` like
-   *      above.
-   *   In both cases, flow leaves a `StoreNode` once the entire chain has been traversed, and the shared
-   *   SSA library is used to find the next use of the variable at the end of the chain.
-   * - Flow can enter a `ReadNode` through an `OperandNode` that represents an address of some variable.
-   *   Flow will then proceed along the chain of addresses computed by `ReadNode.getOuter` (i.e., for an
-   *   expression like `use(a.b.c)` we visit `a`, then `b`, then `c`) and call `readStep` accordingly.
-   *   Once the entire chain has been traversed, flow is transferred to the load instruction that reads
-   *   the final address of the chain.
-   * - Flow can enter a `SsaPhiNode` from an `InstructionNode`, a `StoreNode` or another `SsaPhiNode`
-   *   (in `toPhiNode`), depending on which node provided the previous definition of the underlying
-   *   variable. Flow leaves a `SsaPhiNode` (in `fromPhiNode`) by using the shared SSA library to
-   *   determine the next use of the variable.
-   */
   cached
   newtype TIRDataFlowNode =
     TInstructionNode(Instruction i) or
     TOperandNode(Operand op) or
-    TVariableNode(Variable var) or
-    TStoreNodeInstr(Instruction i) { Ssa::explicitWrite(_, _, i) } or
-    TStoreNodeOperand(ArgumentOperand op) { Ssa::explicitWrite(_, _, op.getDef()) } or
-    TReadNode(Instruction i) { needsPostReadNode(i) } or
-    TSsaPhiNode(Ssa::PhiNode phi)
+    TVariableNode(Variable var)
 
   cached
   predicate localFlowStepCached(Node nodeFrom, Node nodeTo) {
     simpleLocalFlowStep(nodeFrom, nodeTo)
   }
-
-  private predicate needsPostReadNode(Instruction iFrom) {
-    // If the instruction generates an address that flows to a load.
-    Ssa::addressFlowTC(iFrom, Ssa::getSourceAddress(_)) and
-    (
-      // And it is either a field address
-      iFrom instanceof FieldAddressInstruction
-      or
-      // Or it is instruction that either uses or is used for an address that needs a post read node.
-      exists(Instruction mid | needsPostReadNode(mid) |
-        Ssa::addressFlow(mid, iFrom) or Ssa::addressFlow(iFrom, mid)
-      )
-    )
-  }
 }
 
 private import Cached
@@ -239,234 +180,6 @@ class OperandNode extends Node, TOperandNode {
   override string toString() { result = this.getOperand().toString() }
 }
 
-/**
- * INTERNAL: do not use.
- *
- * A `StoreNode` is a node that has been (or is about to be) the
- * source or target of a `storeStep`.
- */
-abstract private class StoreNode extends Node {
-  /** Holds if this node should receive flow from `addr`. */
-  abstract predicate flowInto(Instruction addr);
-
-  override Declaration getEnclosingCallable() { result = this.getFunction() }
-
-  /** Holds if this `StoreNode` is the root of the address computation used by a store operation. */
-  predicate isTerminal() {
-    not exists(this.getInner()) and
-    not storeStep(this, _, _)
-  }
-
-  /** Gets the store operation that uses the address computed by this `StoreNode`. */
-  abstract Instruction getStoreInstruction();
-
-  /** Holds if the store operation associated with this `StoreNode` overwrites the entire variable. */
-  final predicate isCertain() { Ssa::explicitWrite(true, this.getStoreInstruction(), _) }
-
-  /**
-   * Gets the `StoreNode` that computes the address used by this `StoreNode`.
-   */
-  abstract StoreNode getInner();
-
-  /** The inverse of `StoreNode.getInner`. */
-  final StoreNode getOuter() { result.getInner() = this }
-}
-
-class StoreNodeInstr extends StoreNode, TStoreNodeInstr {
-  Instruction instr;
-
-  StoreNodeInstr() { this = TStoreNodeInstr(instr) }
-
-  override predicate flowInto(Instruction addr) { this.getInstruction() = addr }
-
-  /** Gets the underlying instruction. */
-  Instruction getInstruction() { result = instr }
-
-  override Function getFunction() { result = this.getInstruction().getEnclosingFunction() }
-
-  override IRType getType() { result = this.getInstruction().getResultIRType() }
-
-  override Location getLocation() { result = this.getInstruction().getLocation() }
-
-  override string toString() {
-    result = instructionNode(this.getInstruction()).toString() + " [store]"
-  }
-
-  override Instruction getStoreInstruction() {
-    Ssa::explicitWrite(_, result, this.getInstruction())
-  }
-
-  override StoreNodeInstr getInner() {
-    Ssa::addressFlow(result.getInstruction(), this.getInstruction())
-  }
-}
-
-/**
- * To avoid having `PostUpdateNode`s with multiple pre-update nodes (which can cause performance
- * problems) we attach the `PostUpdateNode` that represent output arguments to an operand instead of
- * an instruction.
- *
- * To see why we need this, consider the expression `b->set(new C())`. The IR of this expression looks
- * like (simplified):
- * ```
- * r1(glval<unknown>) = FunctionAddress[set]            :
- * r2(glval<unknown>) = FunctionAddress[operator new]   :
- * r3(unsigned long)  = Constant[8]                     :
- * r4(void *)         = Call[operator new]              : func:r2, 0:r3
- * r5(C *)            = Convert                         : r4
- * r6(glval<unknown>) = FunctionAddress[C]              :
- * v1(void)           = Call[C]                         : func:r6, this:r5
- * v2(void)           = Call[set]                       : func:r1, this:r0, 0:r5
- * ```
- *
- * Notice that both the call to `C` and the call to `set` will have an argument that is the
- * result of calling `operator new` (i.e., `r4`). If we only have `PostUpdateNode`s that are
- * instructions, both `PostUpdateNode`s would have `r4` as their pre-update node.
- *
- * We avoid this issue by having a `PostUpdateNode` for each argument, and let the pre-update node of
- * each `PostUpdateNode` be the argument _operand_, instead of the defining instruction.
- */
-class StoreNodeOperand extends StoreNode, TStoreNodeOperand {
-  ArgumentOperand operand;
-
-  StoreNodeOperand() { this = TStoreNodeOperand(operand) }
-
-  override predicate flowInto(Instruction addr) { this.getOperand().getDef() = addr }
-
-  /** Gets the underlying operand. */
-  Operand getOperand() { result = operand }
-
-  override Function getFunction() { result = operand.getDef().getEnclosingFunction() }
-
-  override IRType getType() { result = operand.getIRType() }
-
-  override Location getLocation() { result = operand.getLocation() }
-
-  override string toString() { result = operandNode(this.getOperand()).toString() + " [store]" }
-
-  override WriteSideEffectInstruction getStoreInstruction() {
-    Ssa::explicitWrite(_, result, operand.getDef())
-  }
-
-  /**
-   * The result of `StoreNodeOperand.getInner` is the `StoreNodeInstr` representation the instruction
-   * that defines this operand. This means the graph of `getInner` looks like this:
-   * ```
-   * I---I---I
-   *  \   \   \
-   *   O   O   O
-   * ```
-   * where each `StoreNodeOperand` "hooks" into the chain computed by `StoreNodeInstr.getInner`.
-   * This means that the chain of `getInner` calls on the argument `&o.f` on an expression
-   * like `func(&o.f)` is:
-   * ```
-   * r4---r3---r2
-   *  \
-   *   0:r4
-   * ```
-   * where the IR for `func(&o.f)` looks like (simplified):
-   * ```
-   * r1(glval<unknown>) = FunctionAddress[func]        :
-   * r2(glval<O>)       = VariableAddress[o]           :
-   * r3(glval<int>)     = FieldAddress[f]              : r2
-   * r4(int *)          = CopyValue                    : r3
-   * v1(void)           = Call[func]                   : func:r1, 0:r4
-   * ```
-   */
-  override StoreNodeInstr getInner() { operand.getDef() = result.getInstruction() }
-}
-
-/**
- * INTERNAL: do not use.
- *
- * A `ReadNode` is a node that has been (or is about to be) the
- * source or target of a `readStep`.
- */
-class ReadNode extends Node, TReadNode {
-  Instruction i;
-
-  ReadNode() { this = TReadNode(i) }
-
-  /** Gets the underlying instruction. */
-  Instruction getInstruction() { result = i }
-
-  override Declaration getEnclosingCallable() { result = this.getFunction() }
-
-  override Function getFunction() { result = this.getInstruction().getEnclosingFunction() }
-
-  override IRType getType() { result = this.getInstruction().getResultIRType() }
-
-  override Location getLocation() { result = this.getInstruction().getLocation() }
-
-  override string toString() {
-    result = instructionNode(this.getInstruction()).toString() + " [read]"
-  }
-
-  /** Gets a load instruction that uses the address computed by this read node. */
-  final Instruction getALoadInstruction() {
-    Ssa::addressFlowTC(this.getInstruction(), Ssa::getSourceAddress(result))
-  }
-
-  /**
-   * Gets a read node with an underlying instruction that is used by this
-   * underlying instruction to compute an address of a load instruction.
-   */
-  final ReadNode getInner() { Ssa::addressFlow(result.getInstruction(), this.getInstruction()) }
-
-  /** The inverse of `ReadNode.getInner`. */
-  final ReadNode getOuter() { result.getInner() = this }
-
-  /** Holds if this read node computes a value that will not be used for any future read nodes. */
-  final predicate isTerminal() {
-    not exists(this.getOuter()) and
-    not readStep(this, _, _)
-  }
-
-  /** Holds if this read node computes a value that has not yet been used for any read operations. */
-  final predicate isInitial() {
-    not exists(this.getInner()) and
-    not readStep(_, _, this)
-  }
-}
-
-/**
- * INTERNAL: do not use.
- *
- * A phi node produced by the shared SSA library, viewed as a node in a data flow graph.
- */
-class SsaPhiNode extends Node, TSsaPhiNode {
-  Ssa::PhiNode phi;
-
-  SsaPhiNode() { this = TSsaPhiNode(phi) }
-
-  /* Get the phi node associated with this node. */
-  Ssa::PhiNode getPhiNode() { result = phi }
-
-  override Declaration getEnclosingCallable() { result = this.getFunction() }
-
-  override Function getFunction() { result = phi.getBasicBlock().getEnclosingFunction() }
-
-  override IRType getType() { result instanceof IRVoidType }
-
-  override Location getLocation() { result = phi.getBasicBlock().getLocation() }
-
-  /** Holds if this phi node has input from the `rnk`'th write operation in block `block`. */
-  final predicate hasInputAtRankInBlock(IRBlock block, int rnk) {
-    this.hasInputAtRankInBlock(block, rnk, _)
-  }
-
-  /**
-   * Holds if this phi node has input from the definition `input` (which is the `rnk`'th write
-   * operation in block `block`).
-   */
-  cached
-  final predicate hasInputAtRankInBlock(IRBlock block, int rnk, Ssa::Definition input) {
-    Ssa::phiHasInputFromBlock(phi, input, _) and input.definesAt(_, block, rnk)
-  }
-
-  override string toString() { result = "Phi" }
-}
-
 /**
  * An expression, viewed as a node in a data flow graph.
  */
@@ -600,14 +313,15 @@ deprecated class UninitializedNode extends Node {
  * Nodes corresponding to AST elements, for example `ExprNode`, usually refer
  * to the value before the update with the exception of `ClassInstanceExpr`,
  * which represents the value after the constructor has run.
+ *
+ * This class exists to match the interface used by Java. There are currently no non-abstract
+ * classes that extend it. When we implement field flow, we can revisit this.
  */
-abstract class PostUpdateNode extends Node {
+abstract class PostUpdateNode extends InstructionNode {
   /**
    * Gets the node before the state update.
    */
   abstract Node getPreUpdateNode();
-
-  override string toString() { result = this.getPreUpdateNode() + " [post update]" }
 }
 
 /**
@@ -618,7 +332,7 @@ abstract class PostUpdateNode extends Node {
  * value, but does not necessarily replace it entirely. For example:
  * ```
  * x.y = 1; // a partial definition of the object `x`.
- * x.y.z = 1; // a partial definition of the object `x.y` and `x`.
+ * x.y.z = 1; // a partial definition of the object `x.y`.
  * x.setY(1); // a partial definition of the object `x`.
  * setY(&x); // a partial definition of the object `x`.
  * ```
@@ -627,34 +341,135 @@ abstract private class PartialDefinitionNode extends PostUpdateNode {
   abstract Expr getDefinedExpr();
 }
 
-private class FieldPartialDefinitionNode extends PartialDefinitionNode, StoreNodeInstr {
-  FieldPartialDefinitionNode() {
-    this.getInstruction() = any(FieldAddressInstruction fai).getObjectAddress()
+private class ExplicitFieldStoreQualifierNode extends PartialDefinitionNode {
+  override ChiInstruction instr;
+  StoreInstruction store;
+
+  ExplicitFieldStoreQualifierNode() {
+    not instr.isResultConflated() and
+    instr.getPartial() = store and
+    (
+      instr.getUpdatedInterval(_, _) or
+      store.getDestinationAddress() instanceof FieldAddressInstruction
+    )
   }
 
-  override Node getPreUpdateNode() { result.asInstruction() = this.getInstruction() }
-
-  override Expr getDefinedExpr() { result = this.getInstruction().getUnconvertedResultExpression() }
-
-  override string toString() { result = PartialDefinitionNode.super.toString() }
-}
-
-private class NonPartialDefinitionPostUpdate extends PostUpdateNode, StoreNodeInstr {
-  NonPartialDefinitionPostUpdate() { not this instanceof PartialDefinitionNode }
-
-  override Node getPreUpdateNode() { result.asInstruction() = this.getInstruction() }
-
-  override string toString() { result = PostUpdateNode.super.toString() }
-}
-
-private class ArgumentPostUpdateNode extends PartialDefinitionNode, StoreNodeOperand {
-  override ArgumentNode getPreUpdateNode() { result.asOperand() = operand }
+  // By using an operand as the result of this predicate we avoid the dataflow inconsistency errors
+  // caused by having multiple nodes sharing the same pre update node. This inconsistency error can cause
+  // a tuple explosion in the big step dataflow relation since it can make many nodes be the entry node
+  // into a big step.
+  override Node getPreUpdateNode() { result.asOperand() = instr.getTotalOperand() }
 
   override Expr getDefinedExpr() {
-    result = this.getOperand().getDef().getUnconvertedResultExpression()
+    result =
+      store
+          .getDestinationAddress()
+          .(FieldAddressInstruction)
+          .getObjectAddress()
+          .getUnconvertedResultExpression()
+  }
+}
+
+/**
+ * Not every store instruction generates a chi instruction that we can attach a PostUpdateNode to.
+ * For instance, an update to a field of a struct containing only one field. Even if the store does
+ * have a chi instruction, a subsequent use of the result of the store may be linked directly to the
+ * result of the store as an inexact definition if the store totally overlaps the use. For these
+ * cases we attach the PostUpdateNode to the store instruction. There's no obvious pre update node
+ * for this case (as the entire memory is updated), so `getPreUpdateNode` is implemented as
+ * `none()`.
+ */
+private class ExplicitSingleFieldStoreQualifierNode extends PartialDefinitionNode {
+  override StoreInstruction instr;
+
+  ExplicitSingleFieldStoreQualifierNode() {
+    (
+      instr.getAUse().isDefinitionInexact()
+      or
+      not exists(ChiInstruction chi | chi.getPartial() = instr)
+    ) and
+    // Without this condition any store would create a `PostUpdateNode`.
+    instr.getDestinationAddress() instanceof FieldAddressInstruction
   }
 
-  override string toString() { result = PartialDefinitionNode.super.toString() }
+  override Node getPreUpdateNode() { none() }
+
+  override Expr getDefinedExpr() {
+    result =
+      instr
+          .getDestinationAddress()
+          .(FieldAddressInstruction)
+          .getObjectAddress()
+          .getUnconvertedResultExpression()
+  }
+}
+
+private FieldAddressInstruction getFieldInstruction(Instruction instr) {
+  result = instr or
+  result = instr.(CopyValueInstruction).getUnary()
+}
+
+/**
+ * The target of a `fieldStoreStepAfterArraySuppression` store step, which is used to convert
+ * an `ArrayContent` to a `FieldContent` when the `WriteSideEffect` instruction stores
+ * into a field. See the QLDoc for `suppressArrayRead` for an example of where such a conversion
+ * is inserted.
+ */
+private class WriteSideEffectFieldStoreQualifierNode extends PartialDefinitionNode {
+  override ChiInstruction instr;
+  WriteSideEffectInstruction write;
+  FieldAddressInstruction field;
+
+  WriteSideEffectFieldStoreQualifierNode() {
+    not instr.isResultConflated() and
+    instr.getPartial() = write and
+    field = getFieldInstruction(write.getDestinationAddress())
+  }
+
+  override Node getPreUpdateNode() { result.asOperand() = instr.getTotalOperand() }
+
+  override Expr getDefinedExpr() {
+    result = field.getObjectAddress().getUnconvertedResultExpression()
+  }
+}
+
+/**
+ * The `PostUpdateNode` that is the target of a `arrayStoreStepChi` store step. The overriden
+ * `ChiInstruction` corresponds to the instruction represented by `node2` in `arrayStoreStepChi`.
+ */
+private class ArrayStoreNode extends PartialDefinitionNode {
+  override ChiInstruction instr;
+  PointerAddInstruction add;
+
+  ArrayStoreNode() {
+    not instr.isResultConflated() and
+    exists(StoreInstruction store |
+      instr.getPartial() = store and
+      add = store.getDestinationAddress()
+    )
+  }
+
+  override Node getPreUpdateNode() { result.asOperand() = instr.getTotalOperand() }
+
+  override Expr getDefinedExpr() { result = add.getLeft().getUnconvertedResultExpression() }
+}
+
+/**
+ * The `PostUpdateNode` that is the target of a `arrayStoreStepChi` store step. The overriden
+ * `ChiInstruction` corresponds to the instruction represented by `node2` in `arrayStoreStepChi`.
+ */
+private class PointerStoreNode extends PostUpdateNode {
+  override ChiInstruction instr;
+
+  PointerStoreNode() {
+    not instr.isResultConflated() and
+    exists(StoreInstruction store |
+      instr.getPartial() = store and
+      store.getDestinationAddress().(CopyValueInstruction).getUnary() instanceof LoadInstruction
+    )
+  }
+
+  override Node getPreUpdateNode() { result.asOperand() = instr.getTotalOperand() }
 }
 
 /**
@@ -733,11 +548,6 @@ class VariableNode extends Node, TVariableNode {
  */
 InstructionNode instructionNode(Instruction instr) { result.getInstruction() = instr }
 
-/**
- * Gets the node corresponding to `operand`.
- */
-OperandNode operandNode(Operand operand) { result.getOperand() = operand }
-
 /**
  * DEPRECATED: use `definitionByReferenceNodeFromArgument` instead.
  *
@@ -804,174 +614,59 @@ predicate simpleLocalFlowStep(Node nodeFrom, Node nodeTo) {
   or
   // Instruction -> Operand flow
   simpleOperandLocalFlowStep(nodeFrom.asInstruction(), nodeTo.asOperand())
-  or
-  // Flow into, through, and out of store nodes
-  StoreNodeFlow::flowInto(nodeFrom.asInstruction(), nodeTo)
-  or
-  StoreNodeFlow::flowThrough(nodeFrom, nodeTo)
-  or
-  StoreNodeFlow::flowOutOf(nodeFrom, nodeTo)
-  or
-  // Flow into, through, and out of read nodes
-  ReadNodeFlow::flowInto(nodeFrom, nodeTo)
-  or
-  ReadNodeFlow::flowThrough(nodeFrom, nodeTo)
-  or
-  ReadNodeFlow::flowOutOf(nodeFrom, nodeTo)
-  or
-  // Adjacent-def-use and adjacent-use-use flow
-  adjacentDefUseFlow(nodeFrom, nodeTo)
 }
 
-private predicate adjacentDefUseFlow(Node nodeFrom, Node nodeTo) {
-  // Flow that isn't already covered by field flow out of store/read nodes.
-  not nodeFrom.asInstruction() = any(StoreNode pun).getStoreInstruction() and
-  not nodeFrom.asInstruction() = any(ReadNode pun).getALoadInstruction() and
-  (
-    //Def-use flow
-    Ssa::ssaFlow(nodeFrom, nodeTo)
-    or
-    // Use-use flow through stores.
-    exists(Instruction loadAddress, Node store |
-      loadAddress = Ssa::getSourceAddressFromNode(nodeFrom) and
-      Ssa::explicitWrite(_, store.asInstruction(), loadAddress) and
-      Ssa::ssaFlow(store, nodeTo)
-    )
+pragma[noinline]
+private predicate getFieldSizeOfClass(Class c, Type type, int size) {
+  exists(Field f |
+    f.getDeclaringType() = c and
+    f.getUnderlyingType() = type and
+    type.getSize() = size
   )
 }
 
-/**
- * INTERNAL: Do not use.
- */
-module ReadNodeFlow {
-  /** Holds if the read node `nodeTo` should receive flow from `nodeFrom`. */
-  predicate flowInto(Node nodeFrom, ReadNode nodeTo) {
-    nodeTo.isInitial() and
-    (
-      // If we entered through an address operand.
-      nodeFrom.asOperand().getDef() = nodeTo.getInstruction()
-      or
-      // If we entered flow through a memory-producing instruction.
-      // This can happen if we have flow to an `InitializeParameterIndirection` through
-      // a `ReadSideEffectInstruction`.
-      exists(Instruction load, Instruction def |
-        def = nodeFrom.asInstruction() and
-        def = Ssa::getSourceValueOperand(load).getAnyDef() and
-        not def = any(StoreNode store).getStoreInstruction() and
-        pragma[only_bind_into](nodeTo).getALoadInstruction() = load
-      )
-    )
-  }
-
-  /**
-   * Holds if the read node `nodeTo` should receive flow from the read node `nodeFrom`.
-   *
-   * This happens when `readFrom` is _not_ the source of a `readStep`, and `nodeTo` is
-   * the `ReadNode` that represents an address that directly depends on `nodeFrom`.
-   */
-  predicate flowThrough(ReadNode nodeFrom, ReadNode nodeTo) {
-    not readStep(nodeFrom, _, _) and
-    nodeFrom.getOuter() = nodeTo
-  }
-
-  /**
-   * Holds if flow should leave the read node `nFrom` and enter the node `nodeTo`.
-   * This happens either because there is use-use flow from one of the variables used in
-   * the read operation, or because we have traversed all the field dereferences in the
-   * read operation.
-   */
-  predicate flowOutOf(ReadNode nFrom, Node nodeTo) {
-    // Use-use flow to another use of the same variable instruction
-    Ssa::ssaFlow(nFrom, nodeTo)
-    or
-    not exists(nFrom.getInner()) and
-    exists(Node store |
-      Ssa::explicitWrite(_, store.asInstruction(), nFrom.getInstruction()) and
-      Ssa::ssaFlow(store, nodeTo)
-    )
-    or
-    // Flow out of read nodes and into memory instructions if we cannot move any further through
-    // read nodes.
-    nFrom.isTerminal() and
-    (
-      exists(Instruction load |
-        load = nodeTo.asInstruction() and
-        Ssa::getSourceAddress(load) = nFrom.getInstruction()
-      )
-      or
-      exists(CallInstruction call, int i |
-        call.getArgument(i) = nodeTo.asInstruction() and
-        call.getArgument(i) = nFrom.getInstruction()
-      )
-    )
-  }
-}
-
-/**
- * INTERNAL: Do not use.
- */
-module StoreNodeFlow {
-  /** Holds if the store node `nodeTo` should receive flow from `nodeFrom`. */
-  predicate flowInto(Instruction instrFrom, StoreNode nodeTo) {
-    nodeTo.flowInto(Ssa::getDestinationAddress(instrFrom))
-  }
-
-  /**
-   * Holds if the store node `nodeTo` should receive flow from `nodeFom`.
-   *
-   * This happens when `nodeFrom` is _not_ the source of a `storeStep`, and `nodeFrom` is
-   * the `Storenode` that represents an address that directly depends on `nodeTo`.
-   */
-  predicate flowThrough(StoreNode nodeFrom, StoreNode nodeTo) {
-    // Flow through a post update node that doesn't need a store step.
-    not storeStep(nodeFrom, _, _) and
-    nodeTo.getOuter() = nodeFrom
-  }
-
-  /**
-   * Holds if flow should leave the store node `nodeFrom` and enter the node `nodeTo`.
-   * This happens because we have traversed an entire chain of field dereferences
-   * after a store operation.
-   */
-  predicate flowOutOf(StoreNodeInstr nFrom, Node nodeTo) {
-    nFrom.isTerminal() and
-    Ssa::ssaFlow(nFrom, nodeTo)
-  }
+private predicate isSingleFieldClass(Type type, Operand op) {
+  exists(int size, Class c |
+    c = op.getType().getUnderlyingType() and
+    c.getSize() = size and
+    getFieldSizeOfClass(c, type, size)
+  )
 }
 
 private predicate simpleOperandLocalFlowStep(Instruction iFrom, Operand opTo) {
   // Propagate flow from an instruction to its exact uses.
-  // We do this for all instruction/operand pairs, except when the operand is the
-  // side effect operand of a ReturnIndirectionInstruction, or the load operand of a LoadInstruction.
-  // This is because we get these flows through the shared SSA library already, and including this
-  // flow here will create multiple dataflow paths which creates a blowup in stage 3 of dataflow.
-  (
-    not any(ReturnIndirectionInstruction ret).getSideEffectOperand() = opTo and
-    not any(LoadInstruction load).getSourceValueOperand() = opTo and
-    not any(ReturnValueInstruction ret).getReturnValueOperand() = opTo
-  ) and
   opTo.getDef() = iFrom
-}
-
-pragma[noinline]
-private predicate getAddressType(LoadInstruction load, Type t) {
-  exists(Instruction address |
-    address = load.getSourceAddress() and
-    t = address.getResultType()
+  or
+  opTo = any(ReadSideEffectInstruction read).getSideEffectOperand() and
+  not iFrom.isResultConflated() and
+  iFrom = opTo.getAnyDef()
+  or
+  // Loading a single `int` from an `int *` parameter is not an exact load since
+  // the parameter may point to an entire array rather than a single `int`. The
+  // following rule ensures that any flow going into the
+  // `InitializeIndirectionInstruction`, even if it's for a different array
+  // element, will propagate to a load of the first element.
+  //
+  // Since we're linking `InitializeIndirectionInstruction` and
+  // `LoadInstruction` together directly, this rule will break if there's any
+  // reassignment of the parameter indirection, including a conditional one that
+  // leads to a phi node.
+  exists(InitializeIndirectionInstruction init |
+    iFrom = init and
+    opTo.(LoadOperand).getAnyDef() = init and
+    // Check that the types match. Otherwise we can get flow from an object to
+    // its fields, which leads to field conflation when there's flow from other
+    // fields to the object elsewhere.
+    init.getParameter().getType().getUnspecifiedType().(DerivedType).getBaseType() =
+      opTo.getType().getUnspecifiedType()
+  )
+  or
+  // Flow from stores to structs with a single field to a load of that field.
+  exists(LoadInstruction load |
+    load.getSourceValueOperand() = opTo and
+    opTo.getAnyDef() = iFrom and
+    isSingleFieldClass(pragma[only_bind_out](pragma[only_bind_out](iFrom).getResultType()), opTo)
   )
-}
-
-/**
- * Like the AST dataflow library, we want to conflate the address and value of a reference. This class
- * represents the `LoadInstruction` that is generated from a reference dereference.
- */
-private class ReferenceDereferenceInstruction extends LoadInstruction {
-  ReferenceDereferenceInstruction() {
-    exists(ReferenceType ref |
-      getAddressType(this, ref) and
-      this.getResultType() = ref.getBaseType()
-    )
-  }
 }
 
 private predicate simpleInstructionLocalFlowStep(Operand opFrom, Instruction iTo) {
@@ -986,8 +681,40 @@ private predicate simpleInstructionLocalFlowStep(Operand opFrom, Instruction iTo
   or
   iTo.(InheritanceConversionInstruction).getUnaryOperand() = opFrom
   or
-  // Conflate references and values like in AST dataflow.
-  iTo.(ReferenceDereferenceInstruction).getSourceAddressOperand() = opFrom
+  // A chi instruction represents a point where a new value (the _partial_
+  // operand) may overwrite an old value (the _total_ operand), but the alias
+  // analysis couldn't determine that it surely will overwrite every bit of it or
+  // that it surely will overwrite no bit of it.
+  //
+  // By allowing flow through the total operand, we ensure that flow is not lost
+  // due to shortcomings of the alias analysis. We may get false flow in cases
+  // where the data is indeed overwritten.
+  //
+  // Flow through the partial operand belongs in the taint-tracking libraries
+  // for now.
+  iTo.getAnOperand().(ChiTotalOperand) = opFrom
+  or
+  // Add flow from write side-effects to non-conflated chi instructions through their
+  // partial operands. From there, a `readStep` will find subsequent reads of that field.
+  // Consider the following example:
+  // ```
+  // void setX(Point* p, int new_x) {
+  //   p->x = new_x;
+  // }
+  // ...
+  // setX(&p, taint());
+  // ```
+  // Here, a `WriteSideEffectInstruction` will provide a new definition for `p->x` after the call to
+  // `setX`, which will be melded into `p` through a chi instruction.
+  exists(ChiInstruction chi | chi = iTo |
+    opFrom.getAnyDef() instanceof WriteSideEffectInstruction and
+    chi.getPartialOperand() = opFrom and
+    not chi.isResultConflated() and
+    // In a call such as `set_value(&x->val);` we don't want the memory representing `x` to receive
+    // dataflow by a simple step. Instead, this is handled by field flow. If we add a simple step here
+    // we can get field-to-object flow.
+    not chi.isPartialUpdate()
+  )
   or
   // Flow through modeled functions
   modelFlow(opFrom, iTo)
@@ -1061,14 +788,25 @@ predicate localInstructionFlow(Instruction e1, Instruction e2) {
  */
 predicate localExprFlow(Expr e1, Expr e2) { localFlow(exprNode(e1), exprNode(e2)) }
 
+/**
+ * Gets a field corresponding to the bit range `[startBit..endBit)` of class `c`, if any.
+ */
+private Field getAField(Class c, int startBit, int endBit) {
+  result.getDeclaringType() = c and
+  startBit = 8 * result.getByteOffset() and
+  endBit = 8 * result.getType().getSize() + startBit
+  or
+  exists(Field f, Class cInner |
+    f = c.getAField() and
+    cInner = f.getUnderlyingType() and
+    result = getAField(cInner, startBit - 8 * f.getByteOffset(), endBit - 8 * f.getByteOffset())
+  )
+}
+
 private newtype TContent =
-  TFieldContent(Field f) {
-    // As reads and writes to union fields can create flow even though the reads and writes
-    // target different fields, we don't want a read (write) to create a read (write) step.
-    not f.getDeclaringType() instanceof Union
-  } or
-  TCollectionContent() or // Not used in C/C++
-  TArrayContent() // Not used in C/C++.
+  TFieldContent(Class c, int startBit, int endBit) { exists(getAField(c, startBit, endBit)) } or
+  TCollectionContent() or
+  TArrayContent()
 
 /**
  * A description of the way data may be stored inside an object. Examples
@@ -1086,13 +824,18 @@ class Content extends TContent {
 
 /** A reference through an instance field. */
 class FieldContent extends Content, TFieldContent {
-  Field f;
+  Class c;
+  int startBit;
+  int endBit;
 
-  FieldContent() { this = TFieldContent(f) }
+  FieldContent() { this = TFieldContent(c, startBit, endBit) }
 
-  override string toString() { result = f.toString() }
+  // Ensure that there's just 1 result for `toString`.
+  override string toString() { result = min(Field f | f = this.getAField() | f.toString()) }
 
-  Field getField() { result = f }
+  predicate hasOffset(Class cl, int start, int end) { cl = c and start = startBit and end = endBit }
+
+  Field getAField() { result = getAField(c, startBit, endBit) }
 }
 
 /** A reference through an array. */

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

@@ -1,662 +0,0 @@
-/**
- * Provides a language-independent implementation of static single assignment
- * (SSA) form.
- */
-
-private import SsaImplSpecific
-
-private BasicBlock getABasicBlockPredecessor(BasicBlock bb) { getABasicBlockSuccessor(result) = bb }
-
-/**
- * Liveness analysis (based on source variables) to restrict the size of the
- * SSA representation.
- */
-private module Liveness {
-  /**
-   * A classification of variable references into reads (of a given kind) and
-   * (certain or uncertain) writes.
-   */
-  private newtype TRefKind =
-    Read(boolean certain) { certain in [false, true] } or
-    Write(boolean certain) { certain in [false, true] }
-
-  private class RefKind extends TRefKind {
-    string toString() {
-      exists(boolean certain | this = Read(certain) and result = "read (" + certain + ")")
-      or
-      exists(boolean certain | this = Write(certain) and result = "write (" + certain + ")")
-    }
-
-    int getOrder() {
-      this = Read(_) and
-      result = 0
-      or
-      this = Write(_) and
-      result = 1
-    }
-  }
-
-  /**
-   * Holds if the `i`th node of basic block `bb` is a reference to `v` of kind `k`.
-   */
-  private predicate ref(BasicBlock bb, int i, SourceVariable v, RefKind k) {
-    exists(boolean certain | variableRead(bb, i, v, certain) | k = Read(certain))
-    or
-    exists(boolean certain | variableWrite(bb, i, v, certain) | k = Write(certain))
-  }
-
-  private newtype OrderedRefIndex =
-    MkOrderedRefIndex(int i, int tag) {
-      exists(RefKind rk | ref(_, i, _, rk) | tag = rk.getOrder())
-    }
-
-  private OrderedRefIndex refOrd(BasicBlock bb, int i, SourceVariable v, RefKind k, int ord) {
-    ref(bb, i, v, k) and
-    result = MkOrderedRefIndex(i, ord) and
-    ord = k.getOrder()
-  }
-
-  /**
-   * Gets the (1-based) rank of the reference to `v` at the `i`th node of
-   * basic block `bb`, which has the given reference kind `k`.
-   *
-   * Reads are considered before writes when they happen at the same index.
-   */
-  private int refRank(BasicBlock bb, int i, SourceVariable v, RefKind k) {
-    refOrd(bb, i, v, k, _) =
-      rank[result](int j, int ord, OrderedRefIndex res |
-        res = refOrd(bb, j, v, _, ord)
-      |
-        res order by j, ord
-      )
-  }
-
-  private int maxRefRank(BasicBlock bb, SourceVariable v) {
-    result = refRank(bb, _, v, _) and
-    not result + 1 = refRank(bb, _, v, _)
-  }
-
-  /**
-   * Gets the (1-based) rank of the first reference to `v` inside basic block `bb`
-   * that is either a read or a certain write.
-   */
-  private int firstReadOrCertainWrite(BasicBlock bb, SourceVariable v) {
-    result =
-      min(int r, RefKind k |
-        r = refRank(bb, _, v, k) and
-        k != Write(false)
-      |
-        r
-      )
-  }
-
-  /**
-   * Holds if source variable `v` is live at the beginning of basic block `bb`.
-   */
-  predicate liveAtEntry(BasicBlock bb, SourceVariable v) {
-    // The first read or certain write to `v` inside `bb` is a read
-    refRank(bb, _, v, Read(_)) = firstReadOrCertainWrite(bb, v)
-    or
-    // There is no certain write to `v` inside `bb`, but `v` is live at entry
-    // to a successor basic block of `bb`
-    not exists(firstReadOrCertainWrite(bb, v)) and
-    liveAtExit(bb, v)
-  }
-
-  /**
-   * Holds if source variable `v` is live at the end of basic block `bb`.
-   */
-  predicate liveAtExit(BasicBlock bb, SourceVariable v) {
-    liveAtEntry(getABasicBlockSuccessor(bb), v)
-  }
-
-  /**
-   * Holds if variable `v` is live in basic block `bb` at index `i`.
-   * The rank of `i` is `rnk` as defined by `refRank()`.
-   */
-  private predicate liveAtRank(BasicBlock bb, int i, SourceVariable v, int rnk) {
-    exists(RefKind kind | rnk = refRank(bb, i, v, kind) |
-      rnk = maxRefRank(bb, v) and
-      liveAtExit(bb, v)
-      or
-      ref(bb, i, v, kind) and
-      kind = Read(_)
-      or
-      exists(RefKind nextKind |
-        liveAtRank(bb, _, v, rnk + 1) and
-        rnk + 1 = refRank(bb, _, v, nextKind) and
-        nextKind != Write(true)
-      )
-    )
-  }
-
-  /**
-   * Holds if variable `v` is live after the (certain or uncertain) write at
-   * index `i` inside basic block `bb`.
-   */
-  predicate liveAfterWrite(BasicBlock bb, int i, SourceVariable v) {
-    exists(int rnk | rnk = refRank(bb, i, v, Write(_)) | liveAtRank(bb, i, v, rnk))
-  }
-}
-
-private import Liveness
-
-/**
- * Holds if `df` is in the dominance frontier of `bb`.
- *
- * This is equivalent to:
- *
- * ```ql
- * bb = getImmediateBasicBlockDominator*(getABasicBlockPredecessor(df)) and
- * not bb = getImmediateBasicBlockDominator+(df)
- * ```
- */
-private predicate inDominanceFrontier(BasicBlock bb, BasicBlock df) {
-  bb = getABasicBlockPredecessor(df) and not bb = getImmediateBasicBlockDominator(df)
-  or
-  exists(BasicBlock prev | inDominanceFrontier(prev, df) |
-    bb = getImmediateBasicBlockDominator(prev) and
-    not bb = getImmediateBasicBlockDominator(df)
-  )
-}
-
-/**
- * Holds if `bb` is in the dominance frontier of a block containing a
- * definition of `v`.
- */
-pragma[noinline]
-private predicate inDefDominanceFrontier(BasicBlock bb, SourceVariable v) {
-  exists(BasicBlock defbb, Definition def |
-    def.definesAt(v, defbb, _) and
-    inDominanceFrontier(defbb, bb)
-  )
-}
-
-cached
-newtype TDefinition =
-  TWriteDef(SourceVariable v, BasicBlock bb, int i) {
-    variableWrite(bb, i, v, _) and
-    liveAfterWrite(bb, i, v)
-  } or
-  TPhiNode(SourceVariable v, BasicBlock bb) {
-    inDefDominanceFrontier(bb, v) and
-    liveAtEntry(bb, v)
-  }
-
-private module SsaDefReaches {
-  newtype TSsaRefKind =
-    SsaRead() or
-    SsaDef()
-
-  /**
-   * A classification of SSA variable references into reads and definitions.
-   */
-  class SsaRefKind extends TSsaRefKind {
-    string toString() {
-      this = SsaRead() and
-      result = "SsaRead"
-      or
-      this = SsaDef() and
-      result = "SsaDef"
-    }
-
-    int getOrder() {
-      this = SsaRead() and
-      result = 0
-      or
-      this = SsaDef() and
-      result = 1
-    }
-  }
-
-  /**
-   * Holds if the `i`th node of basic block `bb` is a reference to `v`,
-   * either a read (when `k` is `SsaRead()`) or an SSA definition (when `k`
-   * is `SsaDef()`).
-   *
-   * Unlike `Liveness::ref`, this includes `phi` nodes.
-   */
-  predicate ssaRef(BasicBlock bb, int i, SourceVariable v, SsaRefKind k) {
-    variableRead(bb, i, v, _) and
-    k = SsaRead()
-    or
-    exists(Definition def | def.definesAt(v, bb, i)) and
-    k = SsaDef()
-  }
-
-  private newtype OrderedSsaRefIndex =
-    MkOrderedSsaRefIndex(int i, SsaRefKind k) { ssaRef(_, i, _, k) }
-
-  private OrderedSsaRefIndex ssaRefOrd(BasicBlock bb, int i, SourceVariable v, SsaRefKind k, int ord) {
-    ssaRef(bb, i, v, k) and
-    result = MkOrderedSsaRefIndex(i, k) and
-    ord = k.getOrder()
-  }
-
-  /**
-   * Gets the (1-based) rank of the reference to `v` at the `i`th node of basic
-   * block `bb`, which has the given reference kind `k`.
-   *
-   * For example, if `bb` is a basic block with a phi node for `v` (considered
-   * to be at index -1), reads `v` at node 2, and defines it at node 5, we have:
-   *
-   * ```ql
-   * ssaRefRank(bb, -1, v, SsaDef()) = 1    // phi node
-   * ssaRefRank(bb,  2, v, Read())   = 2    // read at node 2
-   * ssaRefRank(bb,  5, v, SsaDef()) = 3    // definition at node 5
-   * ```
-   *
-   * Reads are considered before writes when they happen at the same index.
-   */
-  int ssaRefRank(BasicBlock bb, int i, SourceVariable v, SsaRefKind k) {
-    ssaRefOrd(bb, i, v, k, _) =
-      rank[result](int j, int ord, OrderedSsaRefIndex res |
-        res = ssaRefOrd(bb, j, v, _, ord)
-      |
-        res order by j, ord
-      )
-  }
-
-  int maxSsaRefRank(BasicBlock bb, SourceVariable v) {
-    result = ssaRefRank(bb, _, v, _) and
-    not result + 1 = ssaRefRank(bb, _, v, _)
-  }
-
-  /**
-   * Holds if the SSA definition `def` reaches rank index `rnk` in its own
-   * basic block `bb`.
-   */
-  predicate ssaDefReachesRank(BasicBlock bb, Definition def, int rnk, SourceVariable v) {
-    exists(int i |
-      rnk = ssaRefRank(bb, i, v, SsaDef()) and
-      def.definesAt(v, bb, i)
-    )
-    or
-    ssaDefReachesRank(bb, def, rnk - 1, v) and
-    rnk = ssaRefRank(bb, _, v, SsaRead())
-  }
-
-  /**
-   * Holds if the SSA definition of `v` at `def` reaches index `i` in the same
-   * basic block `bb`, without crossing another SSA definition of `v`.
-   */
-  predicate ssaDefReachesReadWithinBlock(SourceVariable v, Definition def, BasicBlock bb, int i) {
-    exists(int rnk |
-      ssaDefReachesRank(bb, def, rnk, v) and
-      rnk = ssaRefRank(bb, i, v, SsaRead())
-    )
-  }
-
-  /**
-   * Holds if the SSA definition of `v` at `def` reaches uncertain SSA definition
-   * `redef` in the same basic block, without crossing another SSA definition of `v`.
-   */
-  predicate ssaDefReachesUncertainDefWithinBlock(
-    SourceVariable v, Definition def, UncertainWriteDefinition redef
-  ) {
-    exists(BasicBlock bb, int rnk, int i |
-      ssaDefReachesRank(bb, def, rnk, v) and
-      rnk = ssaRefRank(bb, i, v, SsaDef()) - 1 and
-      redef.definesAt(v, bb, i)
-    )
-  }
-
-  /**
-   * Same as `ssaRefRank()`, but restricted to a particular SSA definition `def`.
-   */
-  int ssaDefRank(Definition def, SourceVariable v, BasicBlock bb, int i, SsaRefKind k) {
-    v = def.getSourceVariable() and
-    result = ssaRefRank(bb, i, v, k) and
-    (
-      ssaDefReachesRead(_, def, bb, i)
-      or
-      def.definesAt(_, bb, i)
-    )
-  }
-
-  /**
-   * Holds if the reference to `def` at index `i` in basic block `bb` is the
-   * last reference to `v` inside `bb`.
-   */
-  pragma[noinline]
-  predicate lastSsaRef(Definition def, SourceVariable v, BasicBlock bb, int i) {
-    ssaDefRank(def, v, bb, i, _) = maxSsaRefRank(bb, v)
-  }
-
-  predicate defOccursInBlock(Definition def, BasicBlock bb, SourceVariable v) {
-    exists(ssaDefRank(def, v, bb, _, _))
-  }
-
-  pragma[noinline]
-  private predicate ssaDefReachesThroughBlock(Definition def, BasicBlock bb) {
-    ssaDefReachesEndOfBlock(bb, def, _) and
-    not defOccursInBlock(_, bb, def.getSourceVariable())
-  }
-
-  /**
-   * Holds if `def` is accessed in basic block `bb1` (either a read or a write),
-   * `bb2` is a transitive successor of `bb1`, `def` is live at the end of `bb1`,
-   * and the underlying variable for `def` is neither read nor written in any block
-   * on the path between `bb1` and `bb2`.
-   */
-  predicate varBlockReaches(Definition def, BasicBlock bb1, BasicBlock bb2) {
-    defOccursInBlock(def, bb1, _) and
-    bb2 = getABasicBlockSuccessor(bb1)
-    or
-    exists(BasicBlock mid |
-      varBlockReaches(def, bb1, mid) and
-      ssaDefReachesThroughBlock(def, mid) and
-      bb2 = getABasicBlockSuccessor(mid)
-    )
-  }
-
-  /**
-   * Holds if `def` is accessed in basic block `bb1` (either a read or a write),
-   * `def` is read at index `i2` in basic block `bb2`, `bb2` is in a transitive
-   * successor block of `bb1`, and `def` is neither read nor written in any block
-   * on a path between `bb1` and `bb2`.
-   */
-  predicate defAdjacentRead(Definition def, BasicBlock bb1, BasicBlock bb2, int i2) {
-    varBlockReaches(def, bb1, bb2) and
-    ssaRefRank(bb2, i2, def.getSourceVariable(), SsaRead()) = 1
-  }
-}
-
-private import SsaDefReaches
-
-pragma[nomagic]
-predicate liveThrough(BasicBlock bb, SourceVariable v) {
-  liveAtExit(bb, v) and
-  not ssaRef(bb, _, v, SsaDef())
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Holds if the SSA definition of `v` at `def` reaches the end of basic
- * block `bb`, at which point it is still live, without crossing another
- * SSA definition of `v`.
- */
-pragma[nomagic]
-predicate ssaDefReachesEndOfBlock(BasicBlock bb, Definition def, SourceVariable v) {
-  exists(int last | last = maxSsaRefRank(bb, v) |
-    ssaDefReachesRank(bb, def, last, v) and
-    liveAtExit(bb, v)
-  )
-  or
-  // The construction of SSA form ensures that each read of a variable is
-  // dominated by its definition. An SSA definition therefore reaches a
-  // control flow node if it is the _closest_ SSA definition that dominates
-  // the node. If two definitions dominate a node then one must dominate the
-  // other, so therefore the definition of _closest_ is given by the dominator
-  // tree. Thus, reaching definitions can be calculated in terms of dominance.
-  ssaDefReachesEndOfBlock(getImmediateBasicBlockDominator(bb), def, pragma[only_bind_into](v)) and
-  liveThrough(bb, pragma[only_bind_into](v))
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Holds if `inp` is an input to the phi node `phi` along the edge originating in `bb`.
- */
-pragma[nomagic]
-predicate phiHasInputFromBlock(PhiNode phi, Definition inp, BasicBlock bb) {
-  exists(SourceVariable v, BasicBlock bbDef |
-    phi.definesAt(v, bbDef, _) and
-    getABasicBlockPredecessor(bbDef) = bb and
-    ssaDefReachesEndOfBlock(bb, inp, v)
-  )
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Holds if the SSA definition of `v` at `def` reaches a read at index `i` in
- * basic block `bb`, without crossing another SSA definition of `v`. The read
- * is of kind `rk`.
- */
-pragma[nomagic]
-predicate ssaDefReachesRead(SourceVariable v, Definition def, BasicBlock bb, int i) {
-  ssaDefReachesReadWithinBlock(v, def, bb, i)
-  or
-  variableRead(bb, i, v, _) and
-  ssaDefReachesEndOfBlock(getABasicBlockPredecessor(bb), def, v) and
-  not ssaDefReachesReadWithinBlock(v, _, bb, i)
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Holds if `def` is accessed at index `i1` in basic block `bb1` (either a read
- * or a write), `def` is read at index `i2` in basic block `bb2`, and there is a
- * path between them without any read of `def`.
- */
-pragma[nomagic]
-predicate adjacentDefRead(Definition def, BasicBlock bb1, int i1, BasicBlock bb2, int i2) {
-  exists(int rnk |
-    rnk = ssaDefRank(def, _, bb1, i1, _) and
-    rnk + 1 = ssaDefRank(def, _, bb1, i2, SsaRead()) and
-    variableRead(bb1, i2, _, _) and
-    bb2 = bb1
-  )
-  or
-  lastSsaRef(def, _, bb1, i1) and
-  defAdjacentRead(def, bb1, bb2, i2)
-}
-
-pragma[noinline]
-private predicate adjacentDefRead(
-  Definition def, BasicBlock bb1, int i1, BasicBlock bb2, int i2, SourceVariable v
-) {
-  adjacentDefRead(def, bb1, i1, bb2, i2) and
-  v = def.getSourceVariable()
-}
-
-private predicate adjacentDefReachesRead(
-  Definition def, BasicBlock bb1, int i1, BasicBlock bb2, int i2
-) {
-  exists(SourceVariable v | adjacentDefRead(def, bb1, i1, bb2, i2, v) |
-    ssaRef(bb1, i1, v, SsaDef())
-    or
-    variableRead(bb1, i1, v, true)
-  )
-  or
-  exists(BasicBlock bb3, int i3 |
-    adjacentDefReachesRead(def, bb1, i1, bb3, i3) and
-    variableRead(bb3, i3, _, false) and
-    adjacentDefRead(def, bb3, i3, bb2, i2)
-  )
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Same as `adjacentDefRead`, but ignores uncertain reads.
- */
-pragma[nomagic]
-predicate adjacentDefNoUncertainReads(Definition def, BasicBlock bb1, int i1, BasicBlock bb2, int i2) {
-  adjacentDefReachesRead(def, bb1, i1, bb2, i2) and
-  variableRead(bb2, i2, _, true)
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Holds if the node at index `i` in `bb` is a last reference to SSA definition
- * `def`. The reference is last because it can reach another write `next`,
- * without passing through another read or write.
- */
-pragma[nomagic]
-predicate lastRefRedef(Definition def, BasicBlock bb, int i, Definition next) {
-  exists(SourceVariable v |
-    // Next reference to `v` inside `bb` is a write
-    exists(int rnk, int j |
-      rnk = ssaDefRank(def, v, bb, i, _) and
-      next.definesAt(v, bb, j) and
-      rnk + 1 = ssaRefRank(bb, j, v, SsaDef())
-    )
-    or
-    // Can reach a write using one or more steps
-    lastSsaRef(def, v, bb, i) and
-    exists(BasicBlock bb2 |
-      varBlockReaches(def, bb, bb2) and
-      1 = ssaDefRank(next, v, bb2, _, SsaDef())
-    )
-  )
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Holds if `inp` is an immediately preceding definition of uncertain definition
- * `def`. Since `def` is uncertain, the value from the preceding definition might
- * still be valid.
- */
-pragma[nomagic]
-predicate uncertainWriteDefinitionInput(UncertainWriteDefinition def, Definition inp) {
-  lastRefRedef(inp, _, _, def)
-}
-
-private predicate adjacentDefReachesUncertainRead(
-  Definition def, BasicBlock bb1, int i1, BasicBlock bb2, int i2
-) {
-  adjacentDefReachesRead(def, bb1, i1, bb2, i2) and
-  variableRead(bb2, i2, _, false)
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Same as `lastRefRedef`, but ignores uncertain reads.
- */
-pragma[nomagic]
-predicate lastRefRedefNoUncertainReads(Definition def, BasicBlock bb, int i, Definition next) {
-  lastRefRedef(def, bb, i, next) and
-  not variableRead(bb, i, def.getSourceVariable(), false)
-  or
-  exists(BasicBlock bb0, int i0 |
-    lastRefRedef(def, bb0, i0, next) and
-    adjacentDefReachesUncertainRead(def, bb, i, bb0, i0)
-  )
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Holds if the node at index `i` in `bb` is a last reference to SSA
- * definition `def`.
- *
- * That is, the node can reach the end of the enclosing callable, or another
- * SSA definition for the underlying source variable, without passing through
- * another read.
- */
-pragma[nomagic]
-predicate lastRef(Definition def, BasicBlock bb, int i) {
-  lastRefRedef(def, bb, i, _)
-  or
-  lastSsaRef(def, _, bb, i) and
-  (
-    // Can reach exit directly
-    bb instanceof ExitBasicBlock
-    or
-    // Can reach a block using one or more steps, where `def` is no longer live
-    exists(BasicBlock bb2 | varBlockReaches(def, bb, bb2) |
-      not defOccursInBlock(def, bb2, _) and
-      not ssaDefReachesEndOfBlock(bb2, def, _)
-    )
-  )
-}
-
-/**
- * NB: If this predicate is exposed, it should be cached.
- *
- * Same as `lastRefRedef`, but ignores uncertain reads.
- */
-pragma[nomagic]
-predicate lastRefNoUncertainReads(Definition def, BasicBlock bb, int i) {
-  lastRef(def, bb, i) and
-  not variableRead(bb, i, def.getSourceVariable(), false)
-  or
-  exists(BasicBlock bb0, int i0 |
-    lastRef(def, bb0, i0) and
-    adjacentDefReachesUncertainRead(def, bb, i, bb0, i0)
-  )
-}
-
-/** A static single assignment (SSA) definition. */
-class Definition extends TDefinition {
-  /** Gets the source variable underlying this SSA definition. */
-  SourceVariable getSourceVariable() { this.definesAt(result, _, _) }
-
-  /**
-   * Holds if this SSA definition defines `v` at index `i` in basic block `bb`.
-   * Phi nodes are considered to be at index `-1`, while normal variable writes
-   * are at the index of the control flow node they wrap.
-   */
-  final predicate definesAt(SourceVariable v, BasicBlock bb, int i) {
-    this = TWriteDef(v, bb, i)
-    or
-    this = TPhiNode(v, bb) and i = -1
-  }
-
-  /** Gets the basic block to which this SSA definition belongs. */
-  final BasicBlock getBasicBlock() { this.definesAt(_, result, _) }
-
-  /** Gets a textual representation of this SSA definition. */
-  string toString() { none() }
-}
-
-/** An SSA definition that corresponds to a write. */
-class WriteDefinition extends Definition, TWriteDef {
-  private SourceVariable v;
-  private BasicBlock bb;
-  private int i;
-
-  WriteDefinition() { this = TWriteDef(v, bb, i) }
-
-  override string toString() { result = "WriteDef" }
-}
-
-/** A phi node. */
-class PhiNode extends Definition, TPhiNode {
-  override string toString() { result = "Phi" }
-}
-
-/**
- * An SSA definition that represents an uncertain update of the underlying
- * source variable.
- */
-class UncertainWriteDefinition extends WriteDefinition {
-  UncertainWriteDefinition() {
-    exists(SourceVariable v, BasicBlock bb, int i |
-      this.definesAt(v, bb, i) and
-      variableWrite(bb, i, v, false)
-    )
-  }
-}
-
-/** Provides a set of consistency queries. */
-module Consistency {
-  abstract class RelevantDefinition extends Definition {
-    abstract predicate hasLocationInfo(
-      string filepath, int startline, int startcolumn, int endline, int endcolumn
-    );
-  }
-
-  query predicate nonUniqueDef(RelevantDefinition def, SourceVariable v, BasicBlock bb, int i) {
-    ssaDefReachesRead(v, def, bb, i) and
-    not exists(unique(Definition def0 | ssaDefReachesRead(v, def0, bb, i)))
-  }
-
-  query predicate readWithoutDef(SourceVariable v, BasicBlock bb, int i) {
-    variableRead(bb, i, v, _) and
-    not ssaDefReachesRead(v, _, bb, i)
-  }
-
-  query predicate deadDef(RelevantDefinition def, SourceVariable v) {
-    v = def.getSourceVariable() and
-    not ssaDefReachesRead(_, def, _, _) and
-    not phiHasInputFromBlock(_, def, _) and
-    not uncertainWriteDefinitionInput(_, def)
-  }
-}

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

@@ -1,18 +0,0 @@
-private import semmle.code.cpp.ir.IR
-private import SsaInternals as Ssa
-
-class BasicBlock = IRBlock;
-
-class SourceVariable = Ssa::SourceVariable;
-
-BasicBlock getImmediateBasicBlockDominator(BasicBlock bb) { result.immediatelyDominates(bb) }
-
-BasicBlock getABasicBlockSuccessor(BasicBlock bb) { result = bb.getASuccessor() }
-
-class ExitBasicBlock extends IRBlock {
-  ExitBasicBlock() { this.getLastInstruction() instanceof ExitFunctionInstruction }
-}
-
-predicate variableWrite = Ssa::variableWrite/4;
-
-predicate variableRead = Ssa::variableRead/4;

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

@@ -1,639 +0,0 @@
-import SsaImplCommon
-private import cpp as Cpp
-private import semmle.code.cpp.ir.IR
-private import DataFlowUtil
-private import DataFlowImplCommon as DataFlowImplCommon
-private import semmle.code.cpp.models.interfaces.Allocation as Alloc
-private import semmle.code.cpp.models.interfaces.DataFlow as DataFlow
-
-private module SourceVariables {
-  private newtype TSourceVariable =
-    TSourceIRVariable(IRVariable var) or
-    TSourceIRVariableIndirection(InitializeIndirectionInstruction init)
-
-  abstract class SourceVariable extends TSourceVariable {
-    IRVariable var;
-
-    abstract string toString();
-  }
-
-  class SourceIRVariable extends SourceVariable, TSourceIRVariable {
-    SourceIRVariable() { this = TSourceIRVariable(var) }
-
-    IRVariable getIRVariable() { result = var }
-
-    override string toString() { result = this.getIRVariable().toString() }
-  }
-
-  class SourceIRVariableIndirection extends SourceVariable, TSourceIRVariableIndirection {
-    InitializeIndirectionInstruction init;
-
-    SourceIRVariableIndirection() {
-      this = TSourceIRVariableIndirection(init) and var = init.getIRVariable()
-    }
-
-    IRVariable getUnderlyingIRVariable() { result = var }
-
-    override string toString() { result = "*" + this.getUnderlyingIRVariable().toString() }
-  }
-}
-
-import SourceVariables
-
-cached
-private newtype TDefOrUse =
-  TExplicitDef(Instruction store) { explicitWrite(_, store, _) } or
-  TInitializeParam(Instruction instr) {
-    instr instanceof InitializeParameterInstruction
-    or
-    instr instanceof InitializeIndirectionInstruction
-  } or
-  TExplicitUse(Operand op) { isExplicitUse(op) } or
-  TReturnParamIndirection(Operand op) { returnParameterIndirection(op, _) }
-
-pragma[nomagic]
-private int getRank(DefOrUse defOrUse, IRBlock block) {
-  defOrUse =
-    rank[result](int i, DefOrUse cand |
-      block.getInstruction(i) = toInstruction(cand)
-    |
-      cand order by i
-    )
-}
-
-private class DefOrUse extends TDefOrUse {
-  /** Gets the instruction associated with this definition, if any. */
-  Instruction asDef() { none() }
-
-  /** Gets the operand associated with this use, if any. */
-  Operand asUse() { none() }
-
-  /** Gets a textual representation of this element. */
-  abstract string toString();
-
-  /** Gets the block of this definition or use. */
-  abstract IRBlock getBlock();
-
-  /** Holds if this definition or use has rank `rank` in block `block`. */
-  cached
-  final predicate hasRankInBlock(IRBlock block, int rnk) { rnk = getRank(this, block) }
-
-  /** Gets the location of this element. */
-  abstract Cpp::Location getLocation();
-}
-
-private Instruction toInstruction(DefOrUse defOrUse) {
-  result = defOrUse.asDef()
-  or
-  result = defOrUse.asUse().getUse()
-}
-
-abstract class Def extends DefOrUse {
-  Instruction store;
-
-  /** Gets the instruction of this definition. */
-  Instruction getInstruction() { result = store }
-
-  /** Gets the variable that is defined by this definition. */
-  abstract SourceVariable getSourceVariable();
-
-  /** Holds if this definition is guaranteed to happen. */
-  abstract predicate isCertain();
-
-  override Instruction asDef() { result = this.getInstruction() }
-
-  override string toString() { result = "Def" }
-
-  override IRBlock getBlock() { result = this.getInstruction().getBlock() }
-
-  override Cpp::Location getLocation() { result = store.getLocation() }
-}
-
-private class ExplicitDef extends Def, TExplicitDef {
-  ExplicitDef() { this = TExplicitDef(store) }
-
-  override SourceVariable getSourceVariable() {
-    exists(VariableInstruction var |
-      explicitWrite(_, this.getInstruction(), var) and
-      result.(SourceIRVariable).getIRVariable() = var.getIRVariable()
-    )
-  }
-
-  override predicate isCertain() { explicitWrite(true, this.getInstruction(), _) }
-}
-
-private class ParameterDef extends Def, TInitializeParam {
-  ParameterDef() { this = TInitializeParam(store) }
-
-  override SourceVariable getSourceVariable() {
-    result.(SourceIRVariable).getIRVariable() =
-      store.(InitializeParameterInstruction).getIRVariable()
-    or
-    result.(SourceIRVariableIndirection).getUnderlyingIRVariable() =
-      store.(InitializeIndirectionInstruction).getIRVariable()
-  }
-
-  override predicate isCertain() { any() }
-}
-
-abstract class Use extends DefOrUse {
-  Operand use;
-
-  override Operand asUse() { result = use }
-
-  /** Gets the underlying operand of this use. */
-  Operand getOperand() { result = use }
-
-  override string toString() { result = "Use" }
-
-  /** Gets the variable that is used by this use. */
-  abstract SourceVariable getSourceVariable();
-
-  override IRBlock getBlock() { result = use.getUse().getBlock() }
-
-  override Cpp::Location getLocation() { result = use.getLocation() }
-}
-
-private class ExplicitUse extends Use, TExplicitUse {
-  ExplicitUse() { this = TExplicitUse(use) }
-
-  override SourceVariable getSourceVariable() {
-    exists(VariableInstruction var |
-      use.getDef() = var and
-      if use.getUse() instanceof ReadSideEffectInstruction
-      then result.(SourceIRVariableIndirection).getUnderlyingIRVariable() = var.getIRVariable()
-      else result.(SourceIRVariable).getIRVariable() = var.getIRVariable()
-    )
-  }
-}
-
-private class ReturnParameterIndirection extends Use, TReturnParamIndirection {
-  ReturnParameterIndirection() { this = TReturnParamIndirection(use) }
-
-  override SourceVariable getSourceVariable() {
-    exists(ReturnIndirectionInstruction ret |
-      returnParameterIndirection(use, ret) and
-      result.(SourceIRVariableIndirection).getUnderlyingIRVariable() = ret.getIRVariable()
-    )
-  }
-}
-
-private predicate isExplicitUse(Operand op) {
-  op.getDef() instanceof VariableAddressInstruction and
-  not exists(LoadInstruction load |
-    load.getSourceAddressOperand() = op and
-    load.getAUse().getUse() instanceof InitializeIndirectionInstruction
-  )
-}
-
-private predicate returnParameterIndirection(Operand op, ReturnIndirectionInstruction ret) {
-  ret.getSourceAddressOperand() = op
-}
-
-/**
- * Holds if `iFrom` computes an address that is used by `iTo`.
- */
-predicate addressFlow(Instruction iFrom, Instruction iTo) {
-  iTo.(CopyValueInstruction).getSourceValue() = iFrom
-  or
-  iTo.(ConvertInstruction).getUnary() = iFrom
-  or
-  iTo.(CheckedConvertOrNullInstruction).getUnary() = iFrom
-  or
-  iTo.(InheritanceConversionInstruction).getUnary() = iFrom
-  or
-  iTo.(PointerArithmeticInstruction).getLeft() = iFrom
-  or
-  iTo.(FieldAddressInstruction).getObjectAddress() = iFrom
-  or
-  // We traverse `LoadInstruction`s since we want to conclude that the
-  // destination of the store operation `*x = source()` is derived from `x`.
-  iTo.(LoadInstruction).getSourceAddress() = iFrom
-  or
-  // We want to include `ReadSideEffectInstruction`s for the same reason that we include
-  // `LoadInstruction`s, but only when a `WriteSideEffectInstruction` for the same index exists as well
-  // (as otherwise we know that the callee won't override the data). However, given an index `i`, the
-  // destination of the `WriteSideEffectInstruction` for `i` is identical to the source address of the
-  // `ReadSideEffectInstruction` for `i`. So we don't have to talk about the `ReadSideEffectInstruction`
-  // at all.
-  exists(WriteSideEffectInstruction write |
-    write.getPrimaryInstruction() = iTo and
-    write.getDestinationAddress() = iFrom
-  )
-}
-
-/**
- * The reflexive, transitive closure of `addressFlow` that ends as the address of a
- * store or read operation.
- */
-cached
-predicate addressFlowTC(Instruction iFrom, Instruction iTo) {
-  iTo = [getDestinationAddress(_), getSourceAddress(_)] and
-  addressFlow*(iFrom, iTo)
-}
-
-/**
- * Gets the destination address of `instr` if it is a `StoreInstruction` or
- * a `WriteSideEffectInstruction`.
- */
-Instruction getDestinationAddress(Instruction instr) {
-  result =
-    [
-      instr.(StoreInstruction).getDestinationAddress(),
-      instr.(WriteSideEffectInstruction).getDestinationAddress()
-    ]
-}
-
-/** Gets the source address of `instr` if it is an instruction that behaves like a `LoadInstruction`. */
-Instruction getSourceAddress(Instruction instr) { result = getSourceAddressOperand(instr).getDef() }
-
-/**
- * Gets the operand that represents the source address of `instr` if it is an
- * instruction that behaves like a `LoadInstruction`.
- */
-Operand getSourceAddressOperand(Instruction instr) {
-  result =
-    [
-      instr.(LoadInstruction).getSourceAddressOperand(),
-      instr.(ReadSideEffectInstruction).getArgumentOperand()
-    ]
-}
-
-/**
- * Gets the source address of `node` if it's an instruction or operand that
- * behaves like a `LoadInstruction`.
- */
-Instruction getSourceAddressFromNode(Node node) {
-  result = getSourceAddress(node.asInstruction())
-  or
-  result = getSourceAddress(node.asOperand().(SideEffectOperand).getUse())
-}
-
-/** Gets the source value of `instr` if it's an instruction that behaves like a `LoadInstruction`. */
-Instruction getSourceValue(Instruction instr) { result = getSourceValueOperand(instr).getDef() }
-
-/**
- * Gets the operand that represents the source value of `instr` if it's an instruction
- * that behaves like a `LoadInstruction`.
- */
-Operand getSourceValueOperand(Instruction instr) {
-  result = instr.(LoadInstruction).getSourceValueOperand()
-  or
-  result = instr.(ReadSideEffectInstruction).getSideEffectOperand()
-}
-
-/**
- * Holds if `instr` is a `StoreInstruction` or a `WriteSideEffectInstruction` that writes to an address.
- * The addresses is computed using `address`, and `certain` is `true` if the write is guaranteed to overwrite
- * the entire variable.
- */
-cached
-predicate explicitWrite(boolean certain, Instruction instr, Instruction address) {
-  exists(StoreInstruction store |
-    store = instr and addressFlowTC(address, store.getDestinationAddress())
-  |
-    // Set `certain = false` if the address is derived from any instructions that prevents us from
-    // concluding that the entire variable is overridden.
-    if
-      addressFlowTC(any(Instruction i |
-          i instanceof FieldAddressInstruction or
-          i instanceof PointerArithmeticInstruction or
-          i instanceof LoadInstruction or
-          i instanceof InheritanceConversionInstruction
-        ), store.getDestinationAddress())
-    then certain = false
-    else certain = true
-  )
-  or
-  addressFlowTC(address, instr.(WriteSideEffectInstruction).getDestinationAddress()) and
-  certain = false
-}
-
-cached
-private module Cached {
-  private predicate defUseFlow(Node nodeFrom, Node nodeTo) {
-    exists(IRBlock bb1, int i1, IRBlock bb2, int i2, DefOrUse defOrUse, Use use |
-      defOrUse.hasRankInBlock(bb1, i1) and
-      use.hasRankInBlock(bb2, i2) and
-      adjacentDefRead(_, bb1, i1, bb2, i2) and
-      nodeFrom.asInstruction() = toInstruction(defOrUse) and
-      flowOutOfAddressStep(use.getOperand(), nodeTo)
-    )
-  }
-
-  private predicate fromStoreNode(StoreNodeInstr nodeFrom, Node nodeTo) {
-    // Def-use flow from a `StoreNode`.
-    exists(IRBlock bb1, int i1, IRBlock bb2, int i2, Def def, Use use |
-      nodeFrom.isTerminal() and
-      def.getInstruction() = nodeFrom.getStoreInstruction() and
-      def.hasRankInBlock(bb1, i1) and
-      adjacentDefRead(_, bb1, i1, bb2, i2) and
-      use.hasRankInBlock(bb2, i2) and
-      flowOutOfAddressStep(use.getOperand(), nodeTo)
-    )
-    or
-    // This final case is a bit annoying. The write side effect on an expression like `a = new A;` writes
-    // to a fresh address returned by `operator new`, and there's no easy way to use the shared SSA
-    // library to hook that up to the assignment to `a`. So instead we flow to the _first_ use of the
-    // value computed by `operator new` that occurs after `nodeFrom` (to avoid a loop in the
-    // dataflow graph).
-    exists(WriteSideEffectInstruction write, IRBlock bb, int i1, int i2, Operand op |
-      nodeFrom.getInstruction().(CallInstruction).getStaticCallTarget() instanceof
-        Alloc::OperatorNewAllocationFunction and
-      write = nodeFrom.getStoreInstruction() and
-      bb.getInstruction(i1) = write and
-      bb.getInstruction(i2) = op.getUse() and
-      // Flow to an instruction that occurs later in the block.
-      conversionFlow*(nodeFrom.getInstruction(), op.getDef()) and
-      nodeTo.asOperand() = op and
-      i2 > i1 and
-      // There is no previous instruction that also occurs after `nodeFrom`.
-      not exists(Instruction instr, int i |
-        bb.getInstruction(i) = instr and
-        conversionFlow(instr, op.getDef()) and
-        i1 < i and
-        i < i2
-      )
-    )
-  }
-
-  private predicate fromReadNode(ReadNode nodeFrom, Node nodeTo) {
-    exists(IRBlock bb1, int i1, IRBlock bb2, int i2, Use use1, Use use2 |
-      use1.hasRankInBlock(bb1, i1) and
-      use2.hasRankInBlock(bb2, i2) and
-      use1.getOperand().getDef() = nodeFrom.getInstruction() and
-      adjacentDefRead(_, bb1, i1, bb2, i2) and
-      flowOutOfAddressStep(use2.getOperand(), nodeTo)
-    )
-  }
-
-  private predicate fromPhiNode(SsaPhiNode nodeFrom, Node nodeTo) {
-    exists(PhiNode phi, Use use, IRBlock block, int rnk |
-      phi = nodeFrom.getPhiNode() and
-      adjacentDefRead(phi, _, _, block, rnk) and
-      use.hasRankInBlock(block, rnk) and
-      flowOutOfAddressStep(use.getOperand(), nodeTo)
-    )
-  }
-
-  private predicate toPhiNode(Node nodeFrom, SsaPhiNode nodeTo) {
-    // Flow to phi nodes
-    exists(Def def, IRBlock block, int rnk |
-      def.hasRankInBlock(block, rnk) and
-      nodeTo.hasInputAtRankInBlock(block, rnk)
-    |
-      exists(StoreNodeInstr storeNode |
-        storeNode = nodeFrom and
-        storeNode.isTerminal() and
-        def.getInstruction() = storeNode.getStoreInstruction()
-      )
-      or
-      def.getInstruction() = nodeFrom.asInstruction()
-    )
-    or
-    // Phi -> phi flow
-    nodeTo.hasInputAtRankInBlock(_, _, nodeFrom.(SsaPhiNode).getPhiNode())
-  }
-
-  /**
-   * Holds if `nodeFrom` is a read or write, and `nTo` is the next subsequent read of the variable
-   * written (or read) by `storeOrRead`.
-   */
-  cached
-  predicate ssaFlow(Node nodeFrom, Node nodeTo) {
-    // Def-use/use-use flow from an `InstructionNode`.
-    defUseFlow(nodeFrom, nodeTo)
-    or
-    // Def-use flow from a `StoreNode`.
-    fromStoreNode(nodeFrom, nodeTo)
-    or
-    // Use-use flow from a `ReadNode`.
-    fromReadNode(nodeFrom, nodeTo)
-    or
-    fromPhiNode(nodeFrom, nodeTo)
-    or
-    toPhiNode(nodeFrom, nodeTo)
-    or
-    // When we want to transfer flow out of a `StoreNode` we perform two steps:
-    // 1. Find the next use of the address being stored to
-    // 2. Find the `LoadInstruction` that loads the address
-    // When the address being stored into doesn't have a `LoadInstruction` associated with it because it's
-    // passed into a `CallInstruction` we transfer flow to the `ReadSideEffect`, which will then flow into
-    // the callee. We then pickup the flow from the `InitializeIndirectionInstruction` and use the shared
-    // SSA library to determine where the next use of the address that received the flow is.
-    exists(Node init, Node mid |
-      nodeFrom.asInstruction().(InitializeIndirectionInstruction).getIRVariable() =
-        init.asInstruction().(InitializeParameterInstruction).getIRVariable() and
-      // No need for the flow if the next use is the instruction that returns the flow out of the callee.
-      not mid.asInstruction() instanceof ReturnIndirectionInstruction and
-      // Find the next use of the address
-      ssaFlow(init, mid) and
-      // And flow to the next load of that address
-      flowOutOfAddressStep([mid.asInstruction().getAUse(), mid.asOperand()], nodeTo)
-    )
-  }
-
-  /**
-   * Holds if `iTo` is a conversion-like instruction that copies
-   * the value computed by `iFrom`.
-   *
-   * This predicate is used by `fromStoreNode` to find the next use of a pointer that
-   * points to freshly allocated memory.
-   */
-  private predicate conversionFlow(Instruction iFrom, Instruction iTo) {
-    iTo.(CopyValueInstruction).getSourceValue() = iFrom
-    or
-    iTo.(ConvertInstruction).getUnary() = iFrom
-    or
-    iTo.(CheckedConvertOrNullInstruction).getUnary() = iFrom
-    or
-    iTo.(InheritanceConversionInstruction).getUnary() = iFrom
-  }
-
-  pragma[noinline]
-  private predicate callTargetHasInputOutput(
-    CallInstruction call, DataFlow::FunctionInput input, DataFlow::FunctionOutput output
-  ) {
-    exists(DataFlow::DataFlowFunction func |
-      call.getStaticCallTarget() = func and
-      func.hasDataFlow(input, output)
-    )
-  }
-
-  /**
-   * The role of `flowOutOfAddressStep` is to select the node for which we want dataflow to end up in
-   * after the shared SSA library's `adjacentDefRead` predicate has determined that `operand` is the
-   * next use of some variable.
-   *
-   * More precisely, this predicate holds if `operand` is an operand that represents an address, and:
-   * - `nodeTo` is the next load of that address, or
-   * - `nodeTo` is a `ReadNode` that uses the definition of `operand` to start a sequence of reads, or
-   * - `nodeTo` is the outer-most `StoreNode` that uses the address represented by `operand`. We obtain
-   *    use-use flow in this case since `StoreNodeFlow::flowOutOf` will then provide flow to the next of
-   *    of `operand`.
-   *
-   * There is one final (slightly annoying) case: When `operand` is a an argument to a modeled function
-   * without any `ReadSideEffect` (such as `std::move`). Here, the address flows from the argument to
-   * the return value, which might then be read later.
-   */
-  private predicate flowOutOfAddressStep(Operand operand, Node nodeTo) {
-    // Flow into a read node
-    exists(ReadNode readNode | readNode = nodeTo |
-      readNode.isInitial() and
-      operand.getDef() = readNode.getInstruction()
-    )
-    or
-    exists(StoreNodeInstr storeNode, Instruction def |
-      storeNode = nodeTo and
-      def = operand.getDef()
-    |
-      storeNode.isTerminal() and
-      not addressFlow(def, _) and
-      // Only transfer flow to a store node if it doesn't immediately overwrite the address
-      // we've just written to.
-      explicitWrite(false, storeNode.getStoreInstruction(), def)
-    )
-    or
-    // The destination of a store operation has undergone lvalue-to-rvalue conversion and is now a
-    // right-hand-side of a store operation.
-    // Find the next use of the variable in that store operation, and recursively find the load of that
-    // pointer. For example, consider this case:
-    //
-    // ```cpp
-    // int x = source();
-    // int* p = &x;
-    // sink(*p);
-    // ```
-    //
-    // if we want to find the load of the address of `x`, we see that the pointer is stored into `p`,
-    // and we then need to recursively look for the load of `p`.
-    exists(
-      Def def, StoreInstruction store, IRBlock block1, int rnk1, Use use, IRBlock block2, int rnk2
-    |
-      store = def.getInstruction() and
-      store.getSourceValueOperand() = operand and
-      def.hasRankInBlock(block1, rnk1) and
-      use.hasRankInBlock(block2, rnk2) and
-      adjacentDefRead(_, block1, rnk1, block2, rnk2)
-    |
-      // The shared SSA library has determined that `use` is the next use of the operand
-      // so we find the next load of that use (but only if there is no `PostUpdateNode`) we
-      // need to flow into first.
-      not StoreNodeFlow::flowInto(store, _) and
-      flowOutOfAddressStep(use.getOperand(), nodeTo)
-      or
-      // It may also be the case that `store` gives rise to another store step. So let's make sure that
-      // we also take those into account.
-      StoreNodeFlow::flowInto(store, nodeTo)
-    )
-    or
-    // As we find the next load of an address, we might come across another use of the same variable.
-    // In that case, we recursively find the next use of _that_ operand, and continue searching for
-    // the next load of that operand. For example, consider this case:
-    //
-    // ```cpp
-    // int x = source();
-    // use(&x);
-    // int* p = &x;
-    // sink(*p);
-    // ```
-    //
-    // The next use of `x` after its definition is `use(&x)`, but there is a later load of the address
-    // of `x` that we want to flow to. So we use the shared SSA library to find the next load.
-    not operand = getSourceAddressOperand(_) and
-    exists(Use use1, Use use2, IRBlock block1, int rnk1, IRBlock block2, int rnk2 |
-      use1.getOperand() = operand and
-      use1.hasRankInBlock(block1, rnk1) and
-      // Don't flow to the next use if this use is part of a store operation that totally
-      // overrides a variable.
-      not explicitWrite(true, _, use1.getOperand().getDef()) and
-      adjacentDefRead(_, block1, rnk1, block2, rnk2) and
-      use2.hasRankInBlock(block2, rnk2) and
-      flowOutOfAddressStep(use2.getOperand(), nodeTo)
-    )
-    or
-    operand = getSourceAddressOperand(nodeTo.asInstruction())
-    or
-    exists(ReturnIndirectionInstruction ret |
-      ret.getSourceAddressOperand() = operand and
-      ret = nodeTo.asInstruction()
-    )
-    or
-    exists(ReturnValueInstruction ret |
-      ret.getReturnAddressOperand() = operand and
-      nodeTo.asInstruction() = ret
-    )
-    or
-    exists(CallInstruction call, int index, ReadSideEffectInstruction read |
-      call.getArgumentOperand(index) = operand and
-      read = getSideEffectFor(call, index) and
-      nodeTo.asOperand() = read.getSideEffectOperand()
-    )
-    or
-    exists(CopyInstruction copy |
-      not exists(getSourceAddressOperand(copy)) and
-      copy.getSourceValueOperand() = operand and
-      flowOutOfAddressStep(copy.getAUse(), nodeTo)
-    )
-    or
-    exists(ConvertInstruction convert |
-      convert.getUnaryOperand() = operand and
-      flowOutOfAddressStep(convert.getAUse(), nodeTo)
-    )
-    or
-    exists(CheckedConvertOrNullInstruction convert |
-      convert.getUnaryOperand() = operand and
-      flowOutOfAddressStep(convert.getAUse(), nodeTo)
-    )
-    or
-    exists(InheritanceConversionInstruction convert |
-      convert.getUnaryOperand() = operand and
-      flowOutOfAddressStep(convert.getAUse(), nodeTo)
-    )
-    or
-    exists(PointerArithmeticInstruction arith |
-      arith.getLeftOperand() = operand and
-      flowOutOfAddressStep(arith.getAUse(), nodeTo)
-    )
-    or
-    // Flow through a modeled function that has parameter -> return value flow.
-    exists(
-      CallInstruction call, int index, DataFlow::FunctionInput input,
-      DataFlow::FunctionOutput output
-    |
-      callTargetHasInputOutput(call, input, output) and
-      call.getArgumentOperand(index) = operand and
-      not getSideEffectFor(call, index) instanceof ReadSideEffectInstruction and
-      input.isParameter(index) and
-      output.isReturnValue() and
-      flowOutOfAddressStep(call.getAUse(), nodeTo)
-    )
-  }
-}
-
-import Cached
-
-/**
- * Holds if the `i`'th write in block `bb` writes to the variable `v`.
- * `certain` is `true` if the write is guaranteed to overwrite the entire variable.
- */
-predicate variableWrite(IRBlock bb, int i, SourceVariable v, boolean certain) {
-  DataFlowImplCommon::forceCachingInSameStage() and
-  exists(Def def |
-    def.hasRankInBlock(bb, i) and
-    v = def.getSourceVariable() and
-    (if def.isCertain() then certain = true else certain = false)
-  )
-}
-
-/**
- * Holds if the `i`'th read in block `bb` reads to the variable `v`.
- * `certain` is `true` if the read is guaranteed. For C++, this is always the case.
- */
-predicate variableRead(IRBlock bb, int i, SourceVariable v, boolean certain) {
-  exists(Use use |
-    use.hasRankInBlock(bb, i) and
-    v = use.getSourceVariable() and
-    certain = true
-  )
-}

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

@@ -44,6 +44,8 @@ private predicate instructionToOperandTaintStep(Instruction fromInstr, Operand t
     fromInstr = readInstr.getArgumentDef() and
     toOperand = readInstr.getSideEffectOperand()
   )
+  or
+  toOperand.(LoadOperand).getAnyDef() = fromInstr
 }
 
 /**
@@ -82,6 +84,8 @@ private predicate operandToInstructionTaintStep(Operand opFrom, Instruction inst
     instrTo.(FieldAddressInstruction).getField().getDeclaringType() instanceof Union
   )
   or
+  instrTo.(LoadInstruction).getSourceAddressOperand() = opFrom
+  or
   // Flow from an element to an array or union that contains it.
   instrTo.(ChiInstruction).getPartialOperand() = opFrom and
   not instrTo.isResultConflated() and

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

@@ -762,21 +762,11 @@ class ReturnValueInstruction extends ReturnInstruction {
    */
   final LoadOperand getReturnValueOperand() { result = this.getAnOperand() }
 
-  /**
-   * Gets the operand that provides the address of the value being returned by the function.
-   */
-  final AddressOperand getReturnAddressOperand() { result = this.getAnOperand() }
-
   /**
    * Gets the instruction whose result provides the value being returned by the function, if an
    * exact definition is available.
    */
   final Instruction getReturnValue() { result = this.getReturnValueOperand().getDef() }
-
-  /**
-   * Gets the instruction whose result provides the address of the value being returned by the function.
-   */
-  final Instruction getReturnAddress() { result = this.getReturnAddressOperand().getDef() }
 }
 
 /**

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

@@ -20,14 +20,6 @@ private import internal.OperandInternal
 private class TStageOperand =
   TRegisterOperand or TNonSSAMemoryOperand or TPhiOperand or TChiOperand;
 
-/**
- * A known location. Testing `loc instanceof KnownLocation` will account for non existing locations, as
- * opposed to testing `not loc isntanceof UnknownLocation`
- */
-private class KnownLocation extends Language::Location {
-  KnownLocation() { not this instanceof Language::UnknownLocation }
-}
-
 /**
  * An operand of an `Instruction`. The operand represents a use of the result of one instruction
  * (the defining instruction) in another instruction (the use instruction)
@@ -53,10 +45,8 @@ class Operand extends TStageOperand {
 
   /**
    * Gets the location of the source code for this operand.
-   * By default this is where the operand is used, but some subclasses may override this
-   * using `getAnyDef()` if it makes more sense.
    */
-  Language::Location getLocation() { result = this.getUse().getLocation() }
+  final Language::Location getLocation() { result = this.getUse().getLocation() }
 
   /**
    * Gets the function that contains this operand.
@@ -279,10 +269,6 @@ class RegisterOperand extends NonPhiOperand, TRegisterOperand {
 
   final override string toString() { result = tag.toString() }
 
-  // most `RegisterOperands` have a more meaningful location at the definition
-  // the only exception are specific cases of `ThisArgumentOperand`
-  override Language::Location getLocation() { result = this.getAnyDef().getLocation() }
-
   final override Instruction getAnyDef() { result = defInstr }
 
   final override Overlap getDefinitionOverlap() {
@@ -307,7 +293,7 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, TNonPhiMemoryOpe
   final override string toString() { result = tag.toString() }
 
   final override Instruction getAnyDef() {
-    result = unique(Instruction defInstr | this.hasDefinition(defInstr, _))
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
   }
 
   final override Overlap getDefinitionOverlap() { this.hasDefinition(_, result) }
@@ -415,19 +401,11 @@ class ArgumentOperand extends RegisterOperand {
 }
 
 /**
- * An operand representing the implicit `this` argument to a member function
+ * An operand representing the implicit 'this' argument to a member function
  * call.
  */
 class ThisArgumentOperand extends ArgumentOperand {
   override ThisArgumentOperandTag tag;
-
-  // in most cases the def location makes more sense, but in some corner cases it
-  // has an unknown location: in those cases we fall back to the use location
-  override Language::Location getLocation() {
-    if this.getAnyDef().getLocation() instanceof KnownLocation
-    then result = this.getAnyDef().getLocation()
-    else result = this.getUse().getLocation()
-  }
 }
 
 /**

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

@@ -762,21 +762,11 @@ class ReturnValueInstruction extends ReturnInstruction {
    */
   final LoadOperand getReturnValueOperand() { result = this.getAnOperand() }
 
-  /**
-   * Gets the operand that provides the address of the value being returned by the function.
-   */
-  final AddressOperand getReturnAddressOperand() { result = this.getAnOperand() }
-
   /**
    * Gets the instruction whose result provides the value being returned by the function, if an
    * exact definition is available.
    */
   final Instruction getReturnValue() { result = this.getReturnValueOperand().getDef() }
-
-  /**
-   * Gets the instruction whose result provides the address of the value being returned by the function.
-   */
-  final Instruction getReturnAddress() { result = this.getReturnAddressOperand().getDef() }
 }
 
 /**

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

@@ -20,14 +20,6 @@ private import internal.OperandInternal
 private class TStageOperand =
   TRegisterOperand or TNonSSAMemoryOperand or TPhiOperand or TChiOperand;
 
-/**
- * A known location. Testing `loc instanceof KnownLocation` will account for non existing locations, as
- * opposed to testing `not loc isntanceof UnknownLocation`
- */
-private class KnownLocation extends Language::Location {
-  KnownLocation() { not this instanceof Language::UnknownLocation }
-}
-
 /**
  * An operand of an `Instruction`. The operand represents a use of the result of one instruction
  * (the defining instruction) in another instruction (the use instruction)
@@ -53,10 +45,8 @@ class Operand extends TStageOperand {
 
   /**
    * Gets the location of the source code for this operand.
-   * By default this is where the operand is used, but some subclasses may override this
-   * using `getAnyDef()` if it makes more sense.
    */
-  Language::Location getLocation() { result = this.getUse().getLocation() }
+  final Language::Location getLocation() { result = this.getUse().getLocation() }
 
   /**
    * Gets the function that contains this operand.
@@ -279,10 +269,6 @@ class RegisterOperand extends NonPhiOperand, TRegisterOperand {
 
   final override string toString() { result = tag.toString() }
 
-  // most `RegisterOperands` have a more meaningful location at the definition
-  // the only exception are specific cases of `ThisArgumentOperand`
-  override Language::Location getLocation() { result = this.getAnyDef().getLocation() }
-
   final override Instruction getAnyDef() { result = defInstr }
 
   final override Overlap getDefinitionOverlap() {
@@ -307,7 +293,7 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, TNonPhiMemoryOpe
   final override string toString() { result = tag.toString() }
 
   final override Instruction getAnyDef() {
-    result = unique(Instruction defInstr | this.hasDefinition(defInstr, _))
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
   }
 
   final override Overlap getDefinitionOverlap() { this.hasDefinition(_, result) }
@@ -415,19 +401,11 @@ class ArgumentOperand extends RegisterOperand {
 }
 
 /**
- * An operand representing the implicit `this` argument to a member function
+ * An operand representing the implicit 'this' argument to a member function
  * call.
  */
 class ThisArgumentOperand extends ArgumentOperand {
   override ThisArgumentOperandTag tag;
-
-  // in most cases the def location makes more sense, but in some corner cases it
-  // has an unknown location: in those cases we fall back to the use location
-  override Language::Location getLocation() {
-    if this.getAnyDef().getLocation() instanceof KnownLocation
-    then result = this.getAnyDef().getLocation()
-    else result = this.getUse().getLocation()
-  }
 }
 
 /**

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

@@ -762,21 +762,11 @@ class ReturnValueInstruction extends ReturnInstruction {
    */
   final LoadOperand getReturnValueOperand() { result = this.getAnOperand() }
 
-  /**
-   * Gets the operand that provides the address of the value being returned by the function.
-   */
-  final AddressOperand getReturnAddressOperand() { result = this.getAnOperand() }
-
   /**
    * Gets the instruction whose result provides the value being returned by the function, if an
    * exact definition is available.
    */
   final Instruction getReturnValue() { result = this.getReturnValueOperand().getDef() }
-
-  /**
-   * Gets the instruction whose result provides the address of the value being returned by the function.
-   */
-  final Instruction getReturnAddress() { result = this.getReturnAddressOperand().getDef() }
 }
 
 /**

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

@@ -20,14 +20,6 @@ private import internal.OperandInternal
 private class TStageOperand =
   TRegisterOperand or TNonSSAMemoryOperand or TPhiOperand or TChiOperand;
 
-/**
- * A known location. Testing `loc instanceof KnownLocation` will account for non existing locations, as
- * opposed to testing `not loc isntanceof UnknownLocation`
- */
-private class KnownLocation extends Language::Location {
-  KnownLocation() { not this instanceof Language::UnknownLocation }
-}
-
 /**
  * An operand of an `Instruction`. The operand represents a use of the result of one instruction
  * (the defining instruction) in another instruction (the use instruction)
@@ -53,10 +45,8 @@ class Operand extends TStageOperand {
 
   /**
    * Gets the location of the source code for this operand.
-   * By default this is where the operand is used, but some subclasses may override this
-   * using `getAnyDef()` if it makes more sense.
    */
-  Language::Location getLocation() { result = this.getUse().getLocation() }
+  final Language::Location getLocation() { result = this.getUse().getLocation() }
 
   /**
    * Gets the function that contains this operand.
@@ -279,10 +269,6 @@ class RegisterOperand extends NonPhiOperand, TRegisterOperand {
 
   final override string toString() { result = tag.toString() }
 
-  // most `RegisterOperands` have a more meaningful location at the definition
-  // the only exception are specific cases of `ThisArgumentOperand`
-  override Language::Location getLocation() { result = this.getAnyDef().getLocation() }
-
   final override Instruction getAnyDef() { result = defInstr }
 
   final override Overlap getDefinitionOverlap() {
@@ -307,7 +293,7 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, TNonPhiMemoryOpe
   final override string toString() { result = tag.toString() }
 
   final override Instruction getAnyDef() {
-    result = unique(Instruction defInstr | this.hasDefinition(defInstr, _))
+    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
   }
 
   final override Overlap getDefinitionOverlap() { this.hasDefinition(_, result) }
@@ -415,19 +401,11 @@ class ArgumentOperand extends RegisterOperand {
 }
 
 /**
- * An operand representing the implicit `this` argument to a member function
+ * An operand representing the implicit 'this' argument to a member function
  * call.
  */
 class ThisArgumentOperand extends ArgumentOperand {
   override ThisArgumentOperandTag tag;
-
-  // in most cases the def location makes more sense, but in some corner cases it
-  // has an unknown location: in those cases we fall back to the use location
-  override Language::Location getLocation() {
-    if this.getAnyDef().getLocation() instanceof KnownLocation
-    then result = this.getAnyDef().getLocation()
-    else result = this.getUse().getLocation()
-  }
 }
 
 /**

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

@@ -34,16 +34,6 @@ private class IteratorByTraits extends Iterator {
   IteratorByTraits() { exists(IteratorTraits it | it.getIteratorType() = this) }
 }
 
-/**
- * The C++ standard includes an `std::iterator_traits` specialization for pointer types. When
- * this specialization is included in the database, a pointer type `T*` will be an instance
- * of the `IteratorByTraits` class. However, if the `T*` specialization is not in the database,
- * we need to explicitly include them with this class.
- */
-private class IteratorByPointer extends Iterator instanceof PointerType {
-  IteratorByPointer() { not this instanceof IteratorByTraits }
-}
-
 /**
  * A type which has the typedefs expected for an iterator.
  */

cpp/ql/src/AlertSuppression.ql

@@ -18,12 +18,12 @@ class SuppressionComment extends Comment {
     (
       this instanceof CppStyleComment and
       // strip the beginning slashes
-      text = this.getContents().suffix(2)
+      text = getContents().suffix(2)
       or
       this instanceof CStyleComment and
       // strip both the beginning /* and the end */ the comment
       exists(string text0 |
-        text0 = this.getContents().suffix(2) and
+        text0 = getContents().suffix(2) and
         text = text0.prefix(text0.length() - 2)
       ) and
       // The /* */ comment must be a single-line comment

cpp/ql/src/Architecture/Refactoring Opportunities/ClassesWithManyFields.ql

@@ -153,12 +153,12 @@ class ExtClass extends Class {
   }
 
   predicate hasLocationInfo(string path, int startline, int startcol, int endline, int endcol) {
-    if this.hasOneVariableGroup()
+    if hasOneVariableGroup()
     then
       exists(VariableDeclarationGroup vdg | vdg.getClass() = this |
         vdg.hasLocationInfo(path, startline, startcol, endline, endcol)
       )
-    else this.getLocation().hasLocationInfo(path, startline, startcol, endline, endcol)
+    else getLocation().hasLocationInfo(path, startline, startcol, endline, endcol)
   }
 }
 

cpp/ql/src/Best Practices/Unused Entities/UnusedStaticFunctions.ql

@@ -50,16 +50,6 @@ predicate reachableThing(Thing t) {
   exists(Thing mid | reachableThing(mid) and mid.callsOrAccesses() = t)
 }
 
-pragma[nomagic]
-predicate callsOrAccessesPlus(Thing thing1, FunctionToRemove thing2) {
-  thing1.callsOrAccesses() = thing2
-  or
-  exists(Thing mid |
-    thing1.callsOrAccesses() = mid and
-    callsOrAccessesPlus(mid, thing2)
-  )
-}
-
 class Thing extends Locatable {
   Thing() {
     this instanceof Function or
@@ -91,7 +81,7 @@ class FunctionToRemove extends Function {
   }
 
   Thing getOther() {
-    callsOrAccessesPlus(result, this) and
+    result.callsOrAccesses+() = this and
     this != result and
     // We will already be reporting the enclosing function of a
     // local variable, so don't also report the variable

cpp/ql/src/CHANGELOG.md

@@ -1,12 +0,0 @@
-## 0.0.5
-
-### New Queries
-
-* A new query `cpp/certificate-not-checked` has been added for C/C++. The query flags unsafe use of OpenSSL and similar libraries.
-* A new query `cpp/certificate-result-conflation` has been added for C/C++. The query flags unsafe use of OpenSSL and similar libraries.
-
-## 0.0.4
-
-### New Queries
-
-* A new query `cpp/non-https-url` has been added for C/C++. The query flags uses of `http` URLs that might be better replaced with `https`.