[clang][Interp][NFC] Add cleanup() infrastructure to EvalEmitter

Unused for now.

Author: tbaederr

clang/lib/AST/Interp/Context.cpp

@@ -46,6 +46,7 @@ bool Context::evaluateAsRValue(State &Parent, const Expr *E, APValue &Result) {
   auto Res = C.interpretExpr(E, /*ConvertResultToRValue=*/E->isGLValue());
 
   if (Res.isInvalid()) {
+    C.cleanup();
     Stk.clear();
     return false;
   }
@@ -70,6 +71,7 @@ bool Context::evaluate(State &Parent, const Expr *E, APValue &Result) {
 
   auto Res = C.interpretExpr(E);
   if (Res.isInvalid()) {
+    C.cleanup();
     Stk.clear();
     return false;
   }
@@ -97,6 +99,7 @@ bool Context::evaluateAsInitializer(State &Parent, const VarDecl *VD,
       (VD->getType()->isRecordType() || VD->getType()->isArrayType());
   auto Res = C.interpretDecl(VD, CheckGlobalInitialized);
   if (Res.isInvalid()) {
+    C.cleanup();
     Stk.clear();
     return false;
   }

clang/lib/AST/Interp/EvalEmitter.cpp

@@ -32,6 +32,11 @@ EvalEmitter::~EvalEmitter() {
   }
 }
 
+/// Clean up all our resources. This needs to done in failed evaluations before
+/// we call InterpStack::clear(), because there might be a Pointer on the stack
+/// pointing into a Block in the EvalEmitter.
+void EvalEmitter::cleanup() { S.cleanup(); }
+
 EvaluationResult EvalEmitter::interpretExpr(const Expr *E,
                                             bool ConvertResultToRValue) {
   S.setEvalLocation(E->getExprLoc());

clang/lib/AST/Interp/EvalEmitter.h

@@ -38,6 +38,9 @@ class EvalEmitter : public SourceMapper {
                                  bool ConvertResultToRValue = false);
   EvaluationResult interpretDecl(const VarDecl *VD, bool CheckFullyInitialized);
 
+  /// Clean up all resources.
+  void cleanup();
+
   InterpState &getState() { return S; }
 
 protected:

clang/lib/AST/Interp/InterpState.cpp

@@ -33,6 +33,8 @@ InterpState::~InterpState() {
   }
 }
 
+void InterpState::cleanup() {}
+
 Frame *InterpState::getCurrentFrame() {
   if (Current && Current->Caller)
     return Current;

clang/lib/AST/Interp/InterpState.h

@@ -39,6 +39,8 @@ class InterpState final : public State, public SourceMapper {
 
   ~InterpState();
 
+  void cleanup();
+
   InterpState(const InterpState &) = delete;
   InterpState &operator=(const InterpState &) = delete;