PR50767: clear non-distinct debuginfo for function with nodebug definition after undecorated declaration

Fix suggested by Yuanfang Chen:

Non-distinct debuginfo is attached to the function due to the undecorated declaration. Later, when seeing the function definition and `nodebug` attribute, the non-distinct debuginfo should be cleared.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D104777

1 files changed, 8 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 0ca9465..578b8a8 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1304,8 +1304,14 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
   QualType ResTy = BuildFunctionArgList(GD, Args);
 
   // Check if we should generate debug info for this function.
-  if (FD->hasAttr<NoDebugAttr>())
-    DebugInfo = nullptr; // disable debug info indefinitely for this function
+  if (FD->hasAttr<NoDebugAttr>()) {
+    // Clear non-distinct debug info that was possibly attached to the function
+    // due to an earlier declaration without the nodebug attribute
+    if (Fn)
+      Fn->setSubprogram(nullptr);
+    // Disable debug info indefinitely for this function
+    DebugInfo = nullptr;
+  }
 
   // The function might not have a body if we're generating thunks for a
   // function declaration.