From: Amy Huang <akhuang@google.com>
Date: Thu, 30 May 2019 22:04:11 +0000 (+0000)
Subject: Add enums as global variables in the IR metadata.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=83048f49327157f1cbfa6e20335ec322366abcac;p=clang

Add enums as global variables in the IR metadata.

Summary:
Keeps track of the enums that were used by saving them as DIGlobalVariables,
since CodeView emits debug info for global constants.

Reviewers: rnk

Subscribers: aprantl, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D62635

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@362166 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index b79169f0a0..a297025547 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -4240,7 +4240,7 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
 
 llvm::DIDerivedType *
 CGDebugInfo::getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D) {
-  if (!D->isStaticDataMember())
+  if (!D || !D->isStaticDataMember())
     return nullptr;
 
   auto MI = StaticDataMemberCache.find(D->getCanonicalDecl());
@@ -4353,12 +4353,14 @@ void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
   StringRef Name = VD->getName();
   llvm::DIType *Ty = getOrCreateType(VD->getType(), Unit);
 
-  // Do not use global variables for enums.
+  // Do not use global variables for enums, unless for CodeView.
   if (const auto *ECD = dyn_cast<EnumConstantDecl>(VD)) {
     const auto *ED = cast<EnumDecl>(ECD->getDeclContext());
     assert(isa<EnumType>(ED->getTypeForDecl()) && "Enum without EnumType?");
     (void)ED;
-    return;
+
+    if (!CGM.getCodeGenOpts().EmitCodeView)
+      return;
   }
 
   llvm::DIScope *DContext = nullptr;
@@ -4369,8 +4371,8 @@ void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
 
   // Emit definition for static members in CodeView.
   VD = cast<ValueDecl>(VD->getCanonicalDecl());
-  auto *VarD = cast<VarDecl>(VD);
-  if (VarD->isStaticDataMember()) {
+  auto *VarD = dyn_cast<VarDecl>(VD);
+  if (VarD && VarD->isStaticDataMember()) {
     auto *RD = cast<RecordDecl>(VarD->getDeclContext());
     getDeclContextDescriptor(VarD);
     // Ensure that the type is retained even though it's otherwise unreferenced.
diff --git a/test/CodeGenCXX/debug-info-enum.cpp b/test/CodeGenCXX/debug-info-enum.cpp
index 447edba446..088b94dd08 100644
--- a/test/CodeGenCXX/debug-info-enum.cpp
+++ b/test/CodeGenCXX/debug-info-enum.cpp
@@ -1,9 +1,15 @@
 // RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm -debug-info-kind=limited %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -emit-llvm -gcodeview -debug-info-kind=limited %s -o - | FileCheck --check-prefix MSVC %s
 
 // CHECK: !DICompileUnit(
 // CHECK-SAME:           enums: [[ENUMS:![0-9]*]]
 // CHECK: [[ENUMS]] = !{[[E1:![0-9]*]], [[E2:![0-9]*]], [[E3:![0-9]*]]}
 
+// In MSVC check that used enum values are emitted as globals.
+// MSVC: !DICompileUnit(
+// MSVC-SAME:           globals: [[GLOBALS:![0-9]*]]
+// MSVC: [[GLOBALS]] = !{[[G1:![0-9]*]], [[G2:![0-9]*]]}
+
 namespace test1 {
 // CHECK: [[E1]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "e"
 // CHECK-SAME:                      scope: [[TEST1:![0-9]*]]
@@ -12,6 +18,10 @@ namespace test1 {
 // CHECK: [[TEST1]] = !DINamespace(name: "test1"
 // CHECK: [[TEST1_ENUMS]] = !{[[TEST1_E:![0-9]*]]}
 // CHECK: [[TEST1_E]] = !DIEnumerator(name: "E", value: 0, isUnsigned: true)
+
+// MSVC: [[G1]] = !DIGlobalVariableExpression(var: [[VAR1:![0-9]*]],
+// MSVC-SAME:                                 expr: !DIExpression(DW_OP_constu, 0
+// MSVC: [[VAR1]] = distinct !DIGlobalVariable(name: "E"
 enum e { E };
 void foo() {
   int v = E;
@@ -25,6 +35,10 @@ namespace test2 {
 // CHECK-SAME:                      elements: [[TEST1_ENUMS]]
 // CHECK-SAME:                      identifier: "_ZTSN5test21eE"
 // CHECK: [[TEST2]] = !DINamespace(name: "test2"
+
+// MSVC: [[G2]] = !DIGlobalVariableExpression(var: [[VAR2:![0-9]*]],
+// MSVC-SAME:                                 expr: !DIExpression(DW_OP_constu, 0
+// MSVC: [[VAR2]] = distinct !DIGlobalVariable(name: "E"
 enum e { E };
 bool func(int i) {
   return i == E;