[KeyInstr][Clang] Aggregate init + copy (#134639)

This patch is part of a stack that teaches Clang to generate Key Instructions
metadata for C and C++.

RFC:
https://discourse.llvm.org/t/rfc-improving-is-stmt-placement-for-better-interactive-debugging/82668

The feature is only functional in LLVM if LLVM is built with CMake flag
LLVM_EXPERIMENTAL_KEY_INSTRUCTIONs. Eventually that flag will be removed.

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 1743f558..78d71fc 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -258,6 +258,20 @@ template <> struct DominatingValue<RValue> {
   }
 };
 
+/// A scoped helper to set the current source atom group for
+/// CGDebugInfo::addInstToCurrentSourceAtom. A source atom is a source construct
+/// that is "interesting" for debug stepping purposes. We use an atom group
+/// number to track the instruction(s) that implement the functionality for the
+/// atom, plus backup instructions/source locations.
+class ApplyAtomGroup {
+  uint64_t OriginalAtom = 0;
+  CGDebugInfo *DI = nullptr;
+
+public:
+  ApplyAtomGroup(CGDebugInfo *DI);
+  ~ApplyAtomGroup();
+};
+
 /// CodeGenFunction - This class organizes the per-function state that is used
 /// while generating LLVM code.
 class CodeGenFunction : public CodeGenTypeCache {
@@ -3035,6 +3049,7 @@ public:
 
   /// Emit an aggregate assignment.
   void EmitAggregateAssign(LValue Dest, LValue Src, QualType EltTy) {
+    ApplyAtomGroup Grp(getDebugInfo());
     bool IsVolatile = hasVolatileMember(EltTy);
     EmitAggregateCopy(Dest, Src, EltTy, AggValueSlot::MayOverlap, IsVolatile);
   }