C++: As a bonus we now no longer need the 'TTranslatedRangeBasedForVariableDeclaration' IPA branch. This previously existed only to account for the missing 'DeclarationEntry's happening in range-based for loops. But these are now also handled by 'PseudoDeclarationEntry's.

Author: MathiasVP

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

@@ -238,40 +238,6 @@ class TranslatedStaticLocalVariableInitialization extends TranslatedElement,
   final override Function getFunction() { result = var.getFunction() }
 }
 
-/**
- * Gets the `TranslatedRangeBasedForVariableDeclaration` that represents the declaration of
- * `var`.
- */
-TranslatedRangeBasedForVariableDeclaration getTranslatedRangeBasedForVariableDeclaration(
-  LocalVariable var
-) {
-  result.getVariable() = var
-}
-
-/**
- * Represents the IR translation of a compiler-generated variable in a range-based `for` loop.
- */
-class TranslatedRangeBasedForVariableDeclaration extends TranslatedLocalVariableDeclaration,
-  TTranslatedRangeBasedForVariableDeclaration {
-  RangeBasedForStmt forStmt;
-  LocalVariable var;
-
-  TranslatedRangeBasedForVariableDeclaration() {
-    this = TTranslatedRangeBasedForVariableDeclaration(forStmt, var)
-  }
-
-  override string toString() { result = var.toString() }
-
-  override Locatable getAst() { result = var }
-
-  /** DEPRECATED: Alias for getAst */
-  deprecated override Locatable getAST() { result = getAst() }
-
-  override Function getFunction() { result = forStmt.getEnclosingFunction() }
-
-  override LocalVariable getVariable() { result = var }
-}
-
 TranslatedConditionDecl getTranslatedConditionDecl(ConditionDeclExpr expr) {
   result.getAst() = expr
 }

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

@@ -714,16 +714,6 @@ newtype TTranslatedElement =
     translateDeclarationEntry(entry) and
     entry.getDeclaration() instanceof StaticLocalVariable
   } or
-  // A compiler-generated variable to implement a range-based for loop. These don't have a
-  // `DeclarationEntry` in the database, so we have to go by the `Variable` itself.
-  TTranslatedRangeBasedForVariableDeclaration(RangeBasedForStmt forStmt, LocalVariable var) {
-    translateStmt(forStmt) and
-    (
-      var = forStmt.getRangeVariable() or
-      var = forStmt.getBeginEndDeclaration().getADeclaration() or
-      var = forStmt.getVariable()
-    )
-  } or
   // An allocator call in a `new` or `new[]` expression
   TTranslatedAllocatorCall(NewOrNewArrayExpr newExpr) { not ignoreExpr(newExpr) } or
   // An allocation size for a `new` or `new[]` expression

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

@@ -76,6 +76,13 @@ class TranslatedDeclStmt extends TranslatedStmt {
 
   private int getChildCount() { result = count(getDeclarationEntry(_)) }
 
+  PseudoDeclarationEntry getPseudoDeclarationEntry(int index) {
+    result.hasIndex(index) and
+    result.getStmt() = stmt
+  }
+
+  PseudoDeclarationEntry getAPseudoDeclarationEntry() { result = this.getPseudoDeclarationEntry(_) }
+
   /**
    * Gets the `TranslatedDeclarationEntry` child at zero-based index `index`. Since not all
    * `DeclarationEntry` objects have a `TranslatedDeclarationEntry` (e.g. extern functions), we map
@@ -85,7 +92,7 @@ class TranslatedDeclStmt extends TranslatedStmt {
   private TranslatedDeclarationEntry getDeclarationEntry(int index) {
     result =
       rank[index + 1](TranslatedDeclarationEntry entry, int originalIndex |
-        entry = getTranslatedDeclarationEntry(stmt.getDeclarationEntry(originalIndex))
+        entry = getTranslatedDeclarationEntry(this.getPseudoDeclarationEntry(originalIndex))
       |
         entry order by originalIndex
       )
@@ -597,36 +604,32 @@ class TranslatedRangeBasedForStmt extends TranslatedStmt, ConditionContext {
   override RangeBasedForStmt stmt;
 
   override TranslatedElement getChild(int id) {
-    id = 0 and result = getRangeVariableDeclaration()
+    id = 0 and result = getRangeVariableDeclStmt()
     or
-    id = 1 and result = getBeginVariableDeclaration()
+    // Note: `__begin` and `__end` are declared by the same `DeclStmt`
+    id = 1 and result = getBeginEndVariableDeclStmt()
     or
-    id = 2 and result = getEndVariableDeclaration()
+    id = 2 and result = getCondition()
     or
-    id = 3 and result = getCondition()
+    id = 3 and result = getUpdate()
     or
-    id = 4 and result = getUpdate()
+    id = 4 and result = getVariableDeclStmt()
     or
-    id = 5 and result = getVariableDeclaration()
-    or
-    id = 6 and result = getBody()
+    id = 5 and result = getBody()
   }
 
   override Instruction getFirstInstruction() {
-    result = getRangeVariableDeclaration().getFirstInstruction()
+    result = getRangeVariableDeclStmt().getFirstInstruction()
   }
 
   override Instruction getChildSuccessor(TranslatedElement child) {
-    child = getRangeVariableDeclaration() and
-    result = getBeginVariableDeclaration().getFirstInstruction()
-    or
-    child = getBeginVariableDeclaration() and
-    result = getEndVariableDeclaration().getFirstInstruction()
+    child = getRangeVariableDeclStmt() and
+    result = getBeginEndVariableDeclStmt().getFirstInstruction()
     or
-    child = getEndVariableDeclaration() and
+    child = getBeginEndVariableDeclStmt() and
     result = getCondition().getFirstInstruction()
     or
-    child = getVariableDeclaration() and
+    child = getVariableDeclStmt() and
     result = getBody().getFirstInstruction()
     or
     child = getBody() and
@@ -643,23 +646,25 @@ class TranslatedRangeBasedForStmt extends TranslatedStmt, ConditionContext {
   override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) { none() }
 
   override Instruction getChildTrueSuccessor(TranslatedCondition child) {
-    child = getCondition() and result = getVariableDeclaration().getFirstInstruction()
+    child = getCondition() and result = getVariableDeclStmt().getFirstInstruction()
   }
 
   override Instruction getChildFalseSuccessor(TranslatedCondition child) {
     child = getCondition() and result = getParent().getChildSuccessor(this)
   }
 
-  private TranslatedRangeBasedForVariableDeclaration getRangeVariableDeclaration() {
-    result = getTranslatedRangeBasedForVariableDeclaration(stmt.getRangeVariable())
-  }
-
-  private TranslatedRangeBasedForVariableDeclaration getBeginVariableDeclaration() {
-    result = getTranslatedRangeBasedForVariableDeclaration(stmt.getBeginVariable())
+  private TranslatedDeclStmt getRangeVariableDeclStmt() {
+    exists(PseudoVariableDeclarationEntry entry |
+      entry.getDeclaration() = stmt.getRangeVariable() and
+      result.getAPseudoDeclarationEntry() = entry
+    )
   }
 
-  private TranslatedRangeBasedForVariableDeclaration getEndVariableDeclaration() {
-    result = getTranslatedRangeBasedForVariableDeclaration(stmt.getEndVariable())
+  private TranslatedDeclStmt getBeginEndVariableDeclStmt() {
+    exists(PseudoVariableDeclarationEntry entry |
+      entry.getStmt() = stmt.getBeginEndDeclaration() and
+      result.getAPseudoDeclarationEntry() = entry
+    )
   }
 
   // Public for getInstructionBackEdgeSuccessor
@@ -672,8 +677,11 @@ class TranslatedRangeBasedForStmt extends TranslatedStmt, ConditionContext {
     result = getTranslatedExpr(stmt.getUpdate().getFullyConverted())
   }
 
-  private TranslatedRangeBasedForVariableDeclaration getVariableDeclaration() {
-    result = getTranslatedRangeBasedForVariableDeclaration(stmt.getVariable())
+  private TranslatedDeclStmt getVariableDeclStmt() {
+    exists(PseudoVariableDeclarationEntry entry |
+      entry.getDeclaration() = stmt.getVariable() and
+      result.getAPseudoDeclarationEntry() = entry
+    )
   }
 
   private TranslatedStmt getBody() { result = getTranslatedStmt(stmt.getStmt()) }