r181672 - Debug Info: Comment changes in r181393 by request of echristo

[David Blaikie]

Author: dblaikie
Date: Sun May 12 13:05:52 2013
New Revision: 181672

URL: http://llvm.org/viewvc/llvm-project?rev=181672&view=rev
Log:
Debug Info: Comment changes in r181393 by request of echristo

Modified:
    cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
    cfe/trunk/lib/CodeGen/CGDebugInfo.h

Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.cpp?rev=181672&r1=181671&r2=181672&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp Sun May 12 13:05:52 2013
@@ -2172,8 +2172,19 @@ llvm::DIType CGDebugInfo::CreateMemberTy
 }
 
 llvm::DIDescriptor CGDebugInfo::getDeclarationOrDefinition(const Decl *D) {
+  // We only need a declaration (not a definition) of the type - so use whatever
+  // we would otherwise do to get a type for a pointee. (forward declarations in
+  // limited debug info, full definitions (if the type definition is available)
+  // in unlimited debug info)
   if (const TypeDecl *RD = dyn_cast<TypeDecl>(D))
     return CreatePointeeType(QualType(RD->getTypeForDecl(), 0), llvm::DIFile());
+  // Otherwise fall back to a fairly rudimentary cache of existing declarations.
+  // This doesn't handle providing declarations (for functions or variables) for
+  // entities without definitions in this TU, nor when the definition proceeds
+  // the call to this function.
+  // FIXME: This should be split out into more specific maps with support for
+  // emitting forward declarations and merging definitions with declarations,
+  // the same way as we do for types.
   llvm::DenseMap<const Decl *, llvm::WeakVH>::iterator I =
       DeclCache.find(D->getCanonicalDecl());
   if (I == DeclCache.end())

Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.h?rev=181672&r1=181671&r2=181672&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDebugInfo.h (original)
+++ cfe/trunk/lib/CodeGen/CGDebugInfo.h Sun May 12 13:05:52 2013
@@ -95,6 +95,8 @@ 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;