Reapply: DebugInfo: Emit the definition of enums when the definition preceeds the declaration and initial use.

Reverting r208106 to reapply r208065 with a fix for the regression. The
issue was that the enum tried to be built even if the declaration hadn't
been constructed for debug info - presenting problems for enum templates
and typedefs of enums with names for linkage purposes.

Original commit message:

This regressed a little further 208055 though it was already a little
broken.

While the requiresCompleteType optimization should be implemented here.
Future (possibly near future) work.

llvm-svn: 208114

3 files changed, 35 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index cd966a0e7fa..b62cc2546fb 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1427,6 +1427,21 @@ llvm::DIType CGDebugInfo::getOrCreateInterfaceType(QualType D,
   return T;
 }
 
+void CGDebugInfo::completeType(const EnumDecl *ED) {
+  if (DebugKind <= CodeGenOptions::DebugLineTablesOnly)
+    return;
+  QualType Ty = CGM.getContext().getEnumType(ED);
+  void* TyPtr = Ty.getAsOpaquePtr();
+  auto I = TypeCache.find(TyPtr);
+  if (I == TypeCache.end() ||
+      !llvm::DIType(cast<llvm::MDNode>(static_cast<llvm::Value *>(I->second)))
+           .isForwardDecl())
+    return;
+  llvm::DIType Res = CreateTypeDefinition(Ty->castAs<EnumType>());
+  assert(!Res.isForwardDecl());
+  TypeCache[TyPtr] = Res;
+}
+
 void CGDebugInfo::completeType(const RecordDecl *RD) {
   if (DebugKind > CodeGenOptions::LimitedDebugInfo ||
       !CGM.getLangOpts().CPlusPlus)
@@ -1915,6 +1930,20 @@ llvm::DIType CGDebugInfo::CreateEnumType(const EnumType *Ty) {
     return RetTy;
   }
 
+  return CreateTypeDefinition(Ty);
+}
+
+llvm::DIType CGDebugInfo::CreateTypeDefinition(const EnumType *Ty) {
+  const EnumDecl *ED = Ty->getDecl();
+  uint64_t Size = 0;
+  uint64_t Align = 0;
+  if (!ED->getTypeForDecl()->isIncompleteType()) {
+    Size = CGM.getContext().getTypeSize(ED->getTypeForDecl());
+    Align = CGM.getContext().getTypeAlign(ED->getTypeForDecl());
+  }
+
+  SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
+
   // Create DIEnumerator elements for each enumerator.
   SmallVector<llvm::Value *, 16> Enumerators;
   ED = ED->getDefinition();
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 700e3358dea..f7640bc28dd 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -135,6 +135,7 @@ class CGDebugInfo {
   llvm::DIType CreateType(const MemberPointerType *Ty, llvm::DIFile F);
   llvm::DIType CreateType(const AtomicType *Ty, llvm::DIFile F);
   llvm::DIType CreateEnumType(const EnumType *Ty);
+  llvm::DIType CreateTypeDefinition(const EnumType *Ty);
   llvm::DIType CreateSelfType(const QualType &QualTy, llvm::DIType Ty);
   llvm::DIType getTypeOrNull(const QualType);
   llvm::DICompositeType getOrCreateMethodType(const CXXMethodDecl *Method,
@@ -295,6 +296,7 @@ public:
   llvm::DIType getOrCreateInterfaceType(QualType Ty,
                                         SourceLocation Loc);
 
+  void completeType(const EnumDecl *ED);
   void completeType(const RecordDecl *RD);
   void completeRequiredType(const RecordDecl *RD);
   void completeClassData(const RecordDecl *RD);
diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index b7f37462a64..9be633c1c95 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -242,6 +242,10 @@ void CodeGenTypes::UpdateCompletedType(const TagDecl *TD) {
       if (!ConvertType(ED->getIntegerType())->isIntegerTy(32))
         TypeCache.clear();
     }
+    // If necessary, provide the full definition of a type only used with a
+    // declaration so far.
+    if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
+      DI->completeType(ED);
     return;
   }