[clang] bcf6608 - [DebugInfo] Fix for adding "returns cxx udt" option to functions in CodeView.

[Amy Huang via cfe-commits]

Author: Amy Huang
Date: 2020-04-07T09:10:27-07:00
New Revision: bcf66084eddd4d3dbe78fc4ed39a347d5d8d57d4

URL: https://github.com/llvm/llvm-project/commit/bcf66084eddd4d3dbe78fc4ed39a347d5d8d57d4
DIFF: https://github.com/llvm/llvm-project/commit/bcf66084eddd4d3dbe78fc4ed39a347d5d8d57d4.diff

LOG: [DebugInfo] Fix for adding "returns cxx udt" option to functions in CodeView.

Summary:
This change adds DIFlagNonTrivial to forward declarations of
DICompositeType. It adds the flag to nontrivial types and types with
unknown triviality.

It fixes adding the "CxxReturnUdt" flag to functions inconsistently,
since it is added based on whether the return type is marked NonTrivial, and
that changes if the return type was a forward declaration.

continues the discussion at https://reviews.llvm.org/D75215

Bug: https://bugs.llvm.org/show_bug.cgi?id=44785

Reviewers: rnk, dblaikie, aprantl

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77436

Added: 
    clang/test/CodeGenCXX/debug-info-composite-triviality-fwd-decl.cpp

Modified: 
    clang/lib/CodeGen/CGDebugInfo.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 8dc305bbfa8d..74c079b0bd09 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -991,11 +991,21 @@ CGDebugInfo::getOrCreateRecordFwdDecl(const RecordType *Ty,
   uint64_t Size = 0;
   uint32_t Align = 0;
 
+  llvm::DINode::DIFlags Flags = llvm::DINode::FlagFwdDecl;
+
+  // Add flag to nontrivial forward declarations. To be consistent with MSVC,
+  // add the flag if a record has no definition because we don't know whether
+  // it will be trivial or not.
+  if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD))
+    if (!CXXRD->hasDefinition() ||
+        (CXXRD->hasDefinition() && !CXXRD->isTrivial()))
+      Flags |= llvm::DINode::FlagNonTrivial;
+
   // Create the type.
   SmallString<256> Identifier = getTypeIdentifier(Ty, CGM, TheCU);
   llvm::DICompositeType *RetTy = DBuilder.createReplaceableCompositeType(
-      getTagForRecord(RD), RDName, Ctx, DefUnit, Line, 0, Size, Align,
-      llvm::DINode::FlagFwdDecl, Identifier);
+      getTagForRecord(RD), RDName, Ctx, DefUnit, Line, 0, Size, Align, Flags,
+      Identifier);
   if (CGM.getCodeGenOpts().DebugFwdTemplateParams)
     if (auto *TSpecial = dyn_cast<ClassTemplateSpecializationDecl>(RD))
       DBuilder.replaceArrays(RetTy, llvm::DINodeArray(),

diff  --git a/clang/test/CodeGenCXX/debug-info-composite-triviality-fwd-decl.cpp b/clang/test/CodeGenCXX/debug-info-composite-triviality-fwd-decl.cpp
new file mode 100644
index 000000000000..4bf18279b3d5
--- /dev/null
+++ b/clang/test/CodeGenCXX/debug-info-composite-triviality-fwd-decl.cpp
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -emit-llvm -gcodeview -debug-info-kind=limited -x c %s -o - | FileCheck %s --check-prefix CHECK-C
+// RUN: %clang_cc1 -emit-llvm -gcodeview -debug-info-kind=limited -x c++ %s -o - | FileCheck %s --check-prefix CHECK-CXX
+//
+// Test for DIFlagNonTrivial on forward declared DICompositeTypes.
+
+struct Incomplete;
+struct Incomplete (*func_ptr)() = 0;
+// CHECK-C: !DICompositeType({{.*}}name: "Incomplete"
+// CHECK-C-NOT: DIFlagNonTrivial
+// CHECK-CXX: !DICompositeType({{.*}}name: "Incomplete"
+// CHECK-CXX-SAME: DIFlagNonTrivial