Revert "Revert "Debug Info: Using declarations/DW_TAG_imported_declaration of variables, types, and functions.""

This reverts commit r181947 (git d2990ce56a16050cac0d7937ec9919ff54c6df62 )

This addresses one of the two issues identified in r181947, ensuring
that types imported via using declarations only result in a declaration
being emitted for the type, not a definition. The second issue (emitting
using declarations that are unused) is hopefully an acceptable increase
as the real fix for this would be a bit difficult (probably at best we
could record which using directives were involved in lookups - but may
not have been the result of the lookup).

This also ensures that DW_TAG_imported_declarations (& directives) are
not emitted in line-tables-only mode as well as ensuring that typedefs
only require/emit declarations (rather than definitions) for referenced
types.

llvm-svn: 182231

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 853ec2e657f..68fdbd9a8a7 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -36,6 +36,7 @@ namespace clang {
   class ObjCIvarDecl;
   class ClassTemplateSpecializationDecl;
   class GlobalDecl;
+  class UsingDecl;
 
 namespace CodeGen {
   class CodeGenModule;
@@ -96,6 +97,9 @@ class CGDebugInfo {
 
   llvm::DenseMap<const char *, llvm::WeakVH> DIFileCache;
   llvm::DenseMap<const FunctionDecl *, llvm::WeakVH> SPCache;
+  /// \brief Cache declarations relevant to DW_TAG_imported_declarations (C++
+  /// using declarations) that aren't covered by other more specific caches.
+  llvm::DenseMap<const Decl *, llvm::WeakVH> DeclCache;
   llvm::DenseMap<const NamespaceDecl *, llvm::WeakVH> NameSpaceCache;
   llvm::DenseMap<const Decl *, llvm::WeakVH> StaticDataMemberCache;
 
@@ -270,6 +274,9 @@ public:
   /// \brief - Emit C++ using directive.
   void EmitUsingDirective(const UsingDirectiveDecl &UD);
 
+  /// \brief - Emit C++ using declaration.
+  void EmitUsingDecl(const UsingDecl &UD);
+
   /// getOrCreateRecordType - Emit record type's standalone debug info.
   llvm::DIType getOrCreateRecordType(QualType Ty, SourceLocation L);
 
@@ -291,6 +298,8 @@ private:
   /// getContextDescriptor - Get context info for the decl.
   llvm::DIScope getContextDescriptor(const Decl *Decl);
 
+  llvm::DIScope getCurrentContextDescriptor(const Decl *Decl);
+
   /// createRecordFwdDecl - Create a forward decl for a RecordType in a given
   /// context.
   llvm::DIType createRecordFwdDecl(const RecordDecl *, llvm::DIDescriptor);
@@ -334,6 +343,10 @@ private:
   llvm::DIType CreateMemberType(llvm::DIFile Unit, QualType FType,
                                 StringRef Name, uint64_t *Offset);
 
+  /// \brief Retrieve the DIDescriptor, if any, for the canonical form of this
+  /// declaration.
+  llvm::DIDescriptor getDeclarationOrDefinition(const Decl *D);
+
   /// getFunctionDeclaration - Return debug info descriptor to describe method
   /// declaration for the given method definition.
   llvm::DISubprogram getFunctionDeclaration(const Decl *D);