C++: Use the loaded this instead of the this initialization

Author: jketema

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

@@ -2679,7 +2679,7 @@ class TranslatedDestructorFieldDestruction extends TranslatedNonConstantExpr, St
   final override Instruction getInstructionRegisterOperand(InstructionTag tag, OperandTag operandTag) {
     tag = OnlyInstructionTag() and
     operandTag instanceof UnaryOperandTag and
-    result = getTranslatedFunction(getEnclosingFunction(expr)).getInitializeThisInstruction()
+    result = getTranslatedFunction(getEnclosingFunction(expr)).getLoadThisInstruction()
   }
 
   final override Field getInstructionField(InstructionTag tag) {

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

@@ -306,11 +306,11 @@ class TranslatedFunction extends TranslatedRootElement, TTranslatedFunction {
   final predicate hasReturnValue() { hasReturnValue(func) }
 
   /**
-   * Gets the single `InitializeThis` instruction for this function. Holds only
-   * if the function is an instance member function, constructor, or destructor.
+   * Gets the first load of `this` for this function. Holds only if the function
+   * is an instance member function, constructor, or destructor.
    */
-  final Instruction getInitializeThisInstruction() {
-    result = getTranslatedThisParameter(func).getInstruction(InitializerStoreTag())
+  final Instruction getLoadThisInstruction() {
+    result = getTranslatedThisParameter(func).getInstruction(InitializerIndirectAddressTag())
   }
 
   /**
@@ -639,7 +639,7 @@ class TranslatedConstructorInitList extends TranslatedElement, InitializationCon
   }
 
   override Instruction getTargetAddress() {
-    result = getTranslatedFunction(func).getInitializeThisInstruction()
+    result = getTranslatedFunction(func).getLoadThisInstruction()
   }
 
   override Type getTargetType() { result = getTranslatedFunction(func).getThisType() }

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

@@ -950,7 +950,7 @@ abstract class TranslatedBaseStructorCall extends TranslatedStructorCallFromStru
   final override Instruction getInstructionRegisterOperand(InstructionTag tag, OperandTag operandTag) {
     tag = OnlyInstructionTag() and
     operandTag instanceof UnaryOperandTag and
-    result = getTranslatedFunction(this.getFunction()).getInitializeThisInstruction()
+    result = getTranslatedFunction(this.getFunction()).getLoadThisInstruction()
   }
 
   final override predicate getInstructionInheritance(
@@ -1000,7 +1000,7 @@ class TranslatedConstructorDelegationInit extends TranslatedConstructorCallFromC
   }
 
   final override Instruction getReceiver() {
-    result = getTranslatedFunction(this.getFunction()).getInitializeThisInstruction()
+    result = getTranslatedFunction(this.getFunction()).getLoadThisInstruction()
   }
 }