C++: Remove the 'BaseSourceVariableInstruction' column as it's functi…

…onally determined by the address column.

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

@@ -104,11 +104,9 @@ predicate hasRawIndirectInstruction(Instruction instr, int indirectionIndex) {
 cached
 private newtype TDefOrUseImpl =
   TDefAddressImpl(BaseIRVariable v) or
-  TDefImpl(BaseSourceVariableInstruction base, Operand address, int indirectionIndex) {
-    isDef(_, _, address, base, _, indirectionIndex)
-  } or
-  TUseImpl(BaseSourceVariableInstruction base, Operand operand, int indirectionIndex) {
-    isUse(_, operand, base, _, indirectionIndex) and
+  TDefImpl(Operand address, int indirectionIndex) { isDef(_, _, address, _, _, indirectionIndex) } or
+  TUseImpl(Operand operand, int indirectionIndex) {
+    isUse(_, operand, _, _, indirectionIndex) and
     not isDef(true, _, operand, _, _, _)
   } or
   TGlobalUse(GlobalLikeVariable v, IRFunction f, int indirectionIndex) {
@@ -323,17 +321,15 @@ abstract private class OperandBasedDef extends DefImpl {
 }
 
 private class DirectDef extends OperandBasedDef, TDefImpl {
-  BaseSourceVariableInstruction base;
-
-  DirectDef() { this = TDefImpl(base, address, ind) }
+  DirectDef() { this = TDefImpl(address, ind) }
 
-  override BaseSourceVariableInstruction getBase() { result = base }
+  override BaseSourceVariableInstruction getBase() { isDef(_, _, address, result, _, ind) }
 
-  override int getIndirection() { isDef(_, _, address, base, result, ind) }
+  override int getIndirection() { isDef(_, _, address, _, result, ind) }
 
-  override Node0Impl getValue() { isDef(_, result, address, base, _, _) }
+  override Node0Impl getValue() { isDef(_, result, address, _, _, _) }
 
-  override predicate isCertain() { isDef(true, _, address, base, _, ind) }
+  override predicate isCertain() { isDef(true, _, address, _, _, ind) }
 }
 
 private class IteratorDef extends OperandBasedDef, TIteratorDef {
@@ -376,19 +372,19 @@ abstract class UseImpl extends DefOrUseImpl {
 
 abstract private class OperandBasedUse extends UseImpl {
   Operand operand;
-  BaseSourceVariableInstruction base;
 
   bindingset[ind]
   OperandBasedUse() { any() }
 
   final override predicate hasIndexInBlock(IRBlock block, int index) {
     // See the comment in `ssa0`'s `OperandBasedUse` for an explanation of this
     // predicate's implementation.
-    if base.getAst() = any(Cpp::PostfixCrementOperation c).getOperand()
+    if this.getBase().getAst() = any(Cpp::PostfixCrementOperation c).getOperand()
     then
-      exists(Operand op, int indirectionIndex, int indirection |
+      exists(Operand op, int indirectionIndex, int indirection, BaseSourceVariableInstruction base |
         indirectionIndex = this.getIndirectionIndex() and
         indirection = this.getIndirection() and
+        base = this.getBase() and
         op =
           min(Operand cand, int i |
             isUse(_, cand, base, indirection, indirectionIndex) and
@@ -401,31 +397,35 @@ abstract private class OperandBasedUse extends UseImpl {
     else operand.getUse() = block.getInstruction(index)
   }
 
-  final override BaseSourceVariableInstruction getBase() { result = base }
-
   final Operand getOperand() { result = operand }
 
   final override Cpp::Location getLocation() { result = operand.getLocation() }
 }
 
 private class DirectUse extends OperandBasedUse, TUseImpl {
-  DirectUse() { this = TUseImpl(base, operand, ind) }
+  DirectUse() { this = TUseImpl(operand, ind) }
 
-  override int getIndirection() { isUse(_, operand, base, result, ind) }
+  override int getIndirection() { isUse(_, operand, _, result, ind) }
 
-  override predicate isCertain() { isUse(true, operand, base, _, ind) }
+  override predicate isCertain() { isUse(true, operand, _, _, ind) }
 
   override Node getNode() { nodeHasOperand(result, operand, ind) }
+
+  final override BaseSourceVariableInstruction getBase() { isUse(_, operand, result, _, ind) }
 }
 
 private class IteratorUse extends OperandBasedUse, TIteratorUse {
-  IteratorUse() { this = TIteratorUse(operand, base, ind) }
+  BaseSourceVariableInstruction container;
+
+  IteratorUse() { this = TIteratorUse(operand, container, ind) }
 
-  override int getIndirection() { isIteratorUse(base, operand, result, ind) }
+  override int getIndirection() { isIteratorUse(container, operand, result, ind) }
 
   override predicate isCertain() { none() }
 
   override Node getNode() { nodeHasOperand(result, operand, ind) }
+
+  final override BaseSourceVariableInstruction getBase() { result = container }
 }
 
 pragma[nomagic]