Reapply "[clang][Interp][NFC] Save source location of evaluating expression"

This reverts commit ebcb04a.

Author: tbaederr

clang/lib/AST/Interp/EvalEmitter.cpp

@@ -34,6 +34,7 @@ EvalEmitter::~EvalEmitter() {
 
 EvaluationResult EvalEmitter::interpretExpr(const Expr *E,
                                             bool ConvertResultToRValue) {
+  S.setEvalLocation(E->getExprLoc());
   this->ConvertResultToRValue = ConvertResultToRValue;
   EvalResult.setSource(E);
 

clang/lib/AST/Interp/InterpFrame.cpp

@@ -191,8 +191,11 @@ Frame *InterpFrame::getCaller() const {
 }
 
 SourceRange InterpFrame::getCallRange() const {
-  if (!Caller->Func)
-    return S.getRange(nullptr, {});
+  if (!Caller->Func) {
+    if (SourceRange NullRange = S.getRange(nullptr, {}); NullRange.isValid())
+      return NullRange;
+    return S.EvalLocation;
+  }
   return S.getRange(Caller->Func, RetPC - sizeof(uintptr_t));
 }
 

clang/lib/AST/Interp/InterpState.h

@@ -98,6 +98,8 @@ class InterpState final : public State, public SourceMapper {
 
   Context &getContext() const { return Ctx; }
 
+  void setEvalLocation(SourceLocation SL) { this->EvalLocation = SL; }
+
 private:
   /// AST Walker state.
   State &Parent;
@@ -115,6 +117,8 @@ class InterpState final : public State, public SourceMapper {
   Context &Ctx;
   /// The current frame.
   InterpFrame *Current = nullptr;
+  /// Source location of the evaluating expression
+  SourceLocation EvalLocation;
 };
 
 } // namespace interp