Fix a nasty bug in the type remapping stuff that I added that is breaking kc++ on

the build bot in some cases.  The basic issue happens when a source module contains
both a "%foo" type and a "%foo.42" type.  It will see the later one, check to see if
the destination module contains a "%foo" type, and it will return true... because
both the source and destination modules are in the same LLVMContext.  We don't want
to map source types to other source types, so don't do the remapping if the mapped
type came from the source module.

Unfortunately, I've been unable to reduce a decent testcase for this, kc++ is 
pretty great that way.

llvm-svn: 147010

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 4f6013e7020..ba4221d0539 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -148,6 +148,7 @@ bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
   if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
     if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
       return false;
+    
   } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
     if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
       return false;
@@ -567,6 +568,9 @@ void ModuleLinker::computeTypeMapping() {
   std::vector<StructType*> SrcStructTypes;
   SrcM->findUsedStructTypes(SrcStructTypes);
   
+  SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
+                                                 SrcStructTypes.end());
+  
   for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
     StructType *ST = SrcStructTypes[i];
     if (!ST->hasName()) continue;
@@ -579,7 +583,10 @@ void ModuleLinker::computeTypeMapping() {
     
     // Check to see if the destination module has a struct with the prefix name.
     if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
-      TypeMap.addTypeMapping(DST, ST);
+      // Don't use it if this actually came from the source module.  They're in
+      // the same LLVMContext after all.
+      if (!SrcStructTypesSet.count(DST))
+        TypeMap.addTypeMapping(DST, ST);
   }