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

This reverts commit ebcb04ae8825b15fd6aa249a8da0617b877b4705.

clang/lib/AST/Interp/EvalEmitter.cpp

diff --git a/clang/lib/AST/Interp/EvalEmitter.cpp b/clang/lib/AST/Interp/EvalEmitter.cpp
index d764b4b..388c361 100644
--- a/clang/lib/AST/Interp/EvalEmitter.cpp
+++ b/clang/lib/AST/Interp/EvalEmitter.cpp
@@ -34,6 +34,7 @@
 
 EvaluationResult EvalEmitter::interpretExpr(const Expr *E,
                                             bool ConvertResultToRValue) {
+  S.setEvalLocation(E->getExprLoc());
   this->ConvertResultToRValue = ConvertResultToRValue;
   EvalResult.setSource(E);
 

clang/lib/AST/Interp/InterpFrame.cpp

diff --git a/clang/lib/AST/Interp/InterpFrame.cpp b/clang/lib/AST/Interp/InterpFrame.cpp
index 515b1f5..51b0bd5 100644
--- a/clang/lib/AST/Interp/InterpFrame.cpp
+++ b/clang/lib/AST/Interp/InterpFrame.cpp
@@ -191,8 +191,11 @@
 }
 
 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

diff --git a/clang/lib/AST/Interp/InterpState.h b/clang/lib/AST/Interp/InterpState.h
index c17cfad..d483c60 100644
--- a/clang/lib/AST/Interp/InterpState.h
+++ b/clang/lib/AST/Interp/InterpState.h
@@ -98,6 +98,8 @@
 
   Context &getContext() const { return Ctx; }
 
+  void setEvalLocation(SourceLocation SL) { this->EvalLocation = SL; }
+
 private:
   /// AST Walker state.
   State &Parent;
@@ -115,6 +117,8 @@
   Context &Ctx;
   /// The current frame.
   InterpFrame *Current = nullptr;
+  /// Source location of the evaluating expression
+  SourceLocation EvalLocation;
 };
 
 } // namespace interp