Revert "Recommitted r263425 "Supporting all entities declared in lexical scope in LLVM debug info." After fixing PR26942 (the fix is included in this commit)."

This reverts commit r264281.

This change breaks building Chromium for iOS. We'll upload a reproducer
to the PR soon.

llvm-svn: 264333

3 files changed, 14 insertions, 59 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 6f39b093a46..e300ed538ac 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -831,18 +831,15 @@ llvm::DIType *CGDebugInfo::CreateType(const TemplateSpecializationType *Ty,
 
 llvm::DIType *CGDebugInfo::CreateType(const TypedefType *Ty,
                                       llvm::DIFile *Unit) {
-  TypedefNameDecl *TD = Ty->getDecl();
   // We don't set size information, but do specify where the typedef was
   // declared.
-  SourceLocation Loc = TD->getLocation();
-
-  llvm::DIScope *TDContext = getDeclarationLexicalScope(*TD, QualType(Ty, 0));
+  SourceLocation Loc = Ty->getDecl()->getLocation();
 
   // Typedefs are derived from some other type.
   return DBuilder.createTypedef(
       getOrCreateType(Ty->getDecl()->getUnderlyingType(), Unit),
       Ty->getDecl()->getName(), getOrCreateFile(Loc), getLineNumber(Loc),
-      TDContext);
+      getDeclContextDescriptor(Ty->getDecl()));
 }
 
 llvm::DIType *CGDebugInfo::CreateType(const FunctionType *Ty,
@@ -1475,23 +1472,6 @@ llvm::DIType *CGDebugInfo::getOrCreateStandaloneType(QualType D,
   return T;
 }
 
-void CGDebugInfo::recordDeclarationLexicalScope(const Decl &D) {
-  assert(LexicalBlockMap.find(&D) == LexicalBlockMap.end() &&
-         "D is already mapped to lexical block scope");
-  if (!LexicalBlockStack.empty())
-    LexicalBlockMap[&D] = LexicalBlockStack.back();
-}
-
-llvm::DIScope *CGDebugInfo::getDeclarationLexicalScope(const Decl &D,
-                                                       QualType Ty) {
-  auto I = LexicalBlockMap.find(&D);
-  if (I != LexicalBlockMap.end()) {
-    RetainedTypes.push_back(Ty.getAsOpaquePtr());
-    return I->second;
-  }
-  return getDeclContextDescriptor(cast<Decl>(&D));
-}
-
 void CGDebugInfo::completeType(const EnumDecl *ED) {
   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
     return;
@@ -2077,7 +2057,7 @@ llvm::DIType *CGDebugInfo::CreateEnumType(const EnumType *Ty) {
     // entered into the ReplaceMap: finalize() will replace the first
     // FwdDecl with the second and then replace the second with
     // complete type.
-    llvm::DIScope *EDContext = getDeclarationLexicalScope(*ED, QualType(Ty, 0));
+    llvm::DIScope *EDContext = getDeclContextDescriptor(ED);
     llvm::DIFile *DefUnit = getOrCreateFile(ED->getLocation());
     llvm::TempDIScope TmpContext(DBuilder.createReplaceableCompositeType(
         llvm::dwarf::DW_TAG_enumeration_type, "", TheCU, DefUnit, 0));
@@ -2121,7 +2101,7 @@ llvm::DIType *CGDebugInfo::CreateTypeDefinition(const EnumType *Ty) {
 
   llvm::DIFile *DefUnit = getOrCreateFile(ED->getLocation());
   unsigned Line = getLineNumber(ED->getLocation());
-  llvm::DIScope *EnumContext = getDeclarationLexicalScope(*ED, QualType(Ty, 0));
+  llvm::DIScope *EnumContext = getDeclContextDescriptor(ED);
   llvm::DIType *ClassTy =
       ED->isFixed() ? getOrCreateType(ED->getIntegerType(), DefUnit) : nullptr;
   return DBuilder.createEnumerationType(EnumContext, ED->getName(), DefUnit,
@@ -2382,7 +2362,7 @@ llvm::DICompositeType *CGDebugInfo::CreateLimitedType(const RecordType *Ty) {
   unsigned Line = getLineNumber(RD->getLocation());
   StringRef RDName = getClassName(RD);
 
-  llvm::DIScope *RDContext = getDeclarationLexicalScope(*RD, QualType(Ty, 0));
+  llvm::DIScope *RDContext = getDeclContextDescriptor(RD);
 
   // If we ended up creating the type during the context chain construction,
   // just return that.
@@ -2529,15 +2509,8 @@ void CGDebugInfo::collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
   if (DC->isRecord())
     DC = CGM.getContext().getTranslationUnitDecl();
 
-  if (VD->isStaticLocal()) {
-    // Get context for static locals (that are technically globals) the same way
-    // we do for "local" locals -- by using current lexical block.
-    assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
-    VDContext = LexicalBlockStack.back();
-  } else {
-    llvm::DIScope *Mod = getParentModuleOrNull(VD);
-    VDContext = getContextDescriptor(cast<Decl>(DC), Mod ? Mod : TheCU);
-  }
+ llvm::DIScope *Mod = getParentModuleOrNull(VD);
+ VDContext = getContextDescriptor(cast<Decl>(DC), Mod ? Mod : TheCU);
 }
 
 llvm::DISubprogram *
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 795dc0ad42c..989ecad9b46 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -116,11 +116,6 @@ class CGDebugInfo {
 
   /// Keep track of our current nested lexical block.
   std::vector<llvm::TypedTrackingMDRef<llvm::DIScope>> LexicalBlockStack;
-
-  /// Map of AST declaration to its lexical block scope.
-  llvm::DenseMap<const Decl *, llvm::TypedTrackingMDRef<llvm::DIScope>>
-      LexicalBlockMap;
-
   llvm::DenseMap<const Decl *, llvm::TrackingMDRef> RegionMap;
   /// Keep track of LexicalBlockStack counter at the beginning of a
   /// function. This is used to pop unbalanced regions at the end of a
@@ -383,12 +378,6 @@ public:
   /// Emit an Objective-C interface type standalone debug info.
   llvm::DIType *getOrCreateInterfaceType(QualType Ty, SourceLocation Loc);
 
-  /// Map AST declaration to its lexical block scope if available.
-  void recordDeclarationLexicalScope(const Decl &D);
-
-  /// Get lexical scope of AST declaration.
-  llvm::DIScope *getDeclarationLexicalScope(const Decl &D, QualType Ty);
-
   /// Emit standalone debug info for a type.
   llvm::DIType *getOrCreateStandaloneType(QualType Ty, SourceLocation Loc);
 
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index c8a335cb1ab..e0c297508fa 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -87,7 +87,11 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
   case Decl::UsingShadow:
   case Decl::ObjCTypeParam:
     llvm_unreachable("Declaration should not be in declstmts!");
-  case Decl::Function:     // void X();
+  case Decl::Function:  // void X();
+  case Decl::Record:    // struct/union/class X;
+  case Decl::Enum:      // enum X;
+  case Decl::EnumConstant: // enum ? { X = ? }
+  case Decl::CXXRecord: // struct/union/class X; [C++]
   case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
   case Decl::Label:        // __label__ x;
   case Decl::Import:
@@ -97,21 +101,13 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
     // None of these decls require codegen support.
     return;
 
-  case Decl::Record:       // struct/union/class X;
-  case Decl::Enum:         // enum X;
-  case Decl::EnumConstant: // enum ? { X = ? }
-  case Decl::CXXRecord:    // struct/union/class X; [C++]
-    if (CGDebugInfo *DI = getDebugInfo())
-      DI->recordDeclarationLexicalScope(D);
-    return;
-
   case Decl::NamespaceAlias:
     if (CGDebugInfo *DI = getDebugInfo())
-      DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D));
+        DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D));
     return;
   case Decl::Using:          // using X; [C++]
     if (CGDebugInfo *DI = getDebugInfo())
-      DI->EmitUsingDecl(cast<UsingDecl>(D));
+        DI->EmitUsingDecl(cast<UsingDecl>(D));
     return;
   case Decl::UsingDirective: // using namespace X; [C++]
     if (CGDebugInfo *DI = getDebugInfo())
@@ -132,9 +128,6 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
     const TypedefNameDecl &TD = cast<TypedefNameDecl>(D);
     QualType Ty = TD.getUnderlyingType();
 
-    if (CGDebugInfo *DI = getDebugInfo())
-      DI->recordDeclarationLexicalScope(D);
-
     if (Ty->isVariablyModifiedType())
       EmitVariablyModifiedType(Ty);
   }