C++: Print target variable name for Load and Store, if known

Now that we've started printing the targets of `Call` instructions in the IR dumps, I figured I might as well print the names of the variable being loaded or stored as well. We could potentially extend this to match fields, array elements, etc., but that's quite a bit more work.

Author: Dave Bartolomeo

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

@@ -804,12 +804,26 @@ class CopyValueInstruction extends CopyInstruction, UnaryInstruction {
   final override UnaryOperand getSourceValueOperand() { result = getAnOperand() }
 }
 
+/**
+ * Gets a string describing the location pointed to by the specified address operand.
+ */
+private string getAddressOperandDescription(AddressOperand operand) {
+  result = operand.getDef().(VariableAddressInstruction).getIRVariable().toString()
+  or
+  not operand.getDef() instanceof VariableAddressInstruction and
+  result = "?"
+}
+
 /**
  * An instruction that returns a register result containing a copy of its memory operand.
  */
 class LoadInstruction extends CopyInstruction {
   LoadInstruction() { getOpcode() instanceof Opcode::Load }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getSourceAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the value being loaded.
    */
@@ -829,6 +843,10 @@ class LoadInstruction extends CopyInstruction {
 class StoreInstruction extends CopyInstruction {
   StoreInstruction() { getOpcode() instanceof Opcode::Store }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getDestinationAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the location to which the value will be stored.
    */

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

@@ -804,12 +804,26 @@ class CopyValueInstruction extends CopyInstruction, UnaryInstruction {
   final override UnaryOperand getSourceValueOperand() { result = getAnOperand() }
 }
 
+/**
+ * Gets a string describing the location pointed to by the specified address operand.
+ */
+private string getAddressOperandDescription(AddressOperand operand) {
+  result = operand.getDef().(VariableAddressInstruction).getIRVariable().toString()
+  or
+  not operand.getDef() instanceof VariableAddressInstruction and
+  result = "?"
+}
+
 /**
  * An instruction that returns a register result containing a copy of its memory operand.
  */
 class LoadInstruction extends CopyInstruction {
   LoadInstruction() { getOpcode() instanceof Opcode::Load }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getSourceAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the value being loaded.
    */
@@ -829,6 +843,10 @@ class LoadInstruction extends CopyInstruction {
 class StoreInstruction extends CopyInstruction {
   StoreInstruction() { getOpcode() instanceof Opcode::Store }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getDestinationAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the location to which the value will be stored.
    */

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

@@ -804,12 +804,26 @@ class CopyValueInstruction extends CopyInstruction, UnaryInstruction {
   final override UnaryOperand getSourceValueOperand() { result = getAnOperand() }
 }
 
+/**
+ * Gets a string describing the location pointed to by the specified address operand.
+ */
+private string getAddressOperandDescription(AddressOperand operand) {
+  result = operand.getDef().(VariableAddressInstruction).getIRVariable().toString()
+  or
+  not operand.getDef() instanceof VariableAddressInstruction and
+  result = "?"
+}
+
 /**
  * An instruction that returns a register result containing a copy of its memory operand.
  */
 class LoadInstruction extends CopyInstruction {
   LoadInstruction() { getOpcode() instanceof Opcode::Load }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getSourceAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the value being loaded.
    */
@@ -829,6 +843,10 @@ class LoadInstruction extends CopyInstruction {
 class StoreInstruction extends CopyInstruction {
   StoreInstruction() { getOpcode() instanceof Opcode::Store }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getDestinationAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the location to which the value will be stored.
    */

cpp/ql/test/library-tests/ir/ir/raw_ir.expected

@@ -804,12 +804,26 @@ class CopyValueInstruction extends CopyInstruction, UnaryInstruction {
   final override UnaryOperand getSourceValueOperand() { result = getAnOperand() }
 }
 
+/**
+ * Gets a string describing the location pointed to by the specified address operand.
+ */
+private string getAddressOperandDescription(AddressOperand operand) {
+  result = operand.getDef().(VariableAddressInstruction).getIRVariable().toString()
+  or
+  not operand.getDef() instanceof VariableAddressInstruction and
+  result = "?"
+}
+
 /**
  * An instruction that returns a register result containing a copy of its memory operand.
  */
 class LoadInstruction extends CopyInstruction {
   LoadInstruction() { getOpcode() instanceof Opcode::Load }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getSourceAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the value being loaded.
    */
@@ -829,6 +843,10 @@ class LoadInstruction extends CopyInstruction {
 class StoreInstruction extends CopyInstruction {
   StoreInstruction() { getOpcode() instanceof Opcode::Store }
 
+  final override string getImmediateString() {
+    result = getAddressOperandDescription(getDestinationAddressOperand())
+  }
+
   /**
    * Gets the operand that provides the address of the location to which the value will be stored.
    */