From 91155087e905b4004beb2865512d3c86a24f9112 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Wed, 14 Nov 2012 22:29:20 +0000
Subject: [PATCH] Teach the AST importer to merge enumerator constants. Fixes
 <rdar://problem/12676166>, and tested on the LLDB side of the world.

llvm-svn: 167990
---
 clang/lib/AST/ASTImporter.cpp | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 0d4f303..906cc3b 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -122,6 +122,7 @@ namespace clang {
     bool IsStructuralMatch(RecordDecl *FromRecord, RecordDecl *ToRecord,
                            bool Complain = true);
     bool IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToRecord);
+    bool IsStructuralMatch(EnumConstantDecl *FromEC, EnumConstantDecl *ToEC);
     bool IsStructuralMatch(ClassTemplateDecl *From, ClassTemplateDecl *To);
     Decl *VisitDecl(Decl *D);
     Decl *VisitTranslationUnitDecl(TranslationUnitDecl *D);
@@ -2143,7 +2144,18 @@ bool ASTNodeImporter::IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToEnum) {
   return Ctx.IsStructurallyEquivalent(FromEnum, ToEnum);
 }
 
-bool ASTNodeImporter::IsStructuralMatch(ClassTemplateDecl *From, 
+bool ASTNodeImporter::IsStructuralMatch(EnumConstantDecl *FromEC,
+                                        EnumConstantDecl *ToEC)
+{
+  const llvm::APSInt &FromVal = FromEC->getInitVal();
+  const llvm::APSInt &ToVal = ToEC->getInitVal();
+
+  return FromVal.isSigned() == ToVal.isSigned() &&
+         FromVal.getBitWidth() == ToVal.getBitWidth() &&
+         FromVal == ToVal;
+}
+
+bool ASTNodeImporter::IsStructuralMatch(ClassTemplateDecl *From,
                                         ClassTemplateDecl *To) {
   StructuralEquivalenceContext Ctx(Importer.getFromContext(),
                                    Importer.getToContext(),
@@ -2526,7 +2538,13 @@ Decl *ASTNodeImporter::VisitEnumConstantDecl(EnumConstantDecl *D) {
     for (unsigned I = 0, N = FoundDecls.size(); I != N; ++I) {
       if (!FoundDecls[I]->isInIdentifierNamespace(IDNS))
         continue;
-      
+
+      if (EnumConstantDecl *FoundEnumConstant
+            = dyn_cast<EnumConstantDecl>(FoundDecls[I])) {
+        if (IsStructuralMatch(D, FoundEnumConstant))
+          return Importer.Imported(D, FoundEnumConstant);
+      }
+
       ConflictingDecls.push_back(FoundDecls[I]);
     }
     
-- 
2.7.4