1 files changed, 11 insertions, 8 deletions
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 5c8f57dc005..d32ed7f8b7b 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -762,15 +762,18 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
 
   // Emit subprogram debug descriptor.
   if (CGDebugInfo *DI = getDebugInfo()) {
+    // Reconstruct the type from the argument list so that implicit parameters,
+    // such as 'this' and 'vtt', show up in the debug info. Preserve the calling
+    // convention.
+    CallingConv CC = CallingConv::CC_C;
+    if (auto *FD = dyn_cast_or_null<FunctionDecl>(D))
+      if (const auto *SrcFnTy = FD->getType()->getAs<FunctionType>())
+        CC = SrcFnTy->getCallConv();
     SmallVector<QualType, 16> ArgTypes;
-    for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
-	 i != e; ++i) {
-      ArgTypes.push_back((*i)->getType());
-    }
-
-    QualType FnType =
-      getContext().getFunctionType(RetTy, ArgTypes,
-                                   FunctionProtoType::ExtProtoInfo());
+    for (const VarDecl *VD : Args)
+      ArgTypes.push_back(VD->getType());
+    QualType FnType = getContext().getFunctionType(
+        RetTy, ArgTypes, FunctionProtoType::ExtProtoInfo(CC));
     DI->EmitFunctionStart(GD, Loc, StartLoc, FnType, CurFn, Builder);
   }