Debug Info: Fix LTO type uniquing for C++ member declarations

based on the ODR.

This adds an OdrMemberMap to DwarfDebug which is used to unique C++
member function declarations based on the unique identifier of their
containing class and their mangled name.
We can't use the usual DIRef mechanism here because DIScopes are indexed
using their entire MDNode, including decl_file and decl_line, which need
not be unique (see testcase).

Prior to this change multiple redundant member function declarations would
end up in the same uniqued DW_TAG_class_type.

llvm-svn: 203982

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index bd1d304b71d..baf87323178 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -353,6 +353,9 @@ class DwarfDebug : public AsmPrinterHandler {
   /// of in DwarfCompileUnit.
   DenseMap<const MDNode *, DIE *> MDTypeNodeToDieMap;
 
+  // Used to unique C++ member function declarations.
+  StringMap<const MDNode *> OdrMemberMap;
+
   // Stores the current file ID for a given compile unit.
   DenseMap<unsigned, unsigned> FileIDCUMap;
   // Source id map, i.e. CUID, source filename and directory,
@@ -702,6 +705,11 @@ public:
     return MDTypeNodeToDieMap.lookup(TypeMD);
   }
 
+  /// \brief Look up or create an entry in the OdrMemberMap.
+  const MDNode *&getOrCreateOdrMember(StringRef Key) {
+    return OdrMemberMap.GetOrCreateValue(Key).getValue();
+  }
+
   /// \brief Emit all Dwarf sections that should come prior to the
   /// content.
   void beginModule();