Dead code elimination

[oota-llvm.git] / lib / Linker / LinkModules.cpp

diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index d69395cf9b2aa2b9155279eef49845efdb070e75..8487c83ce36ab910fddc391d34580794d6636250 100644 (file)
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -159,7 +159,7 @@ static bool RecursiveResolveTypesI(const Type *DstTy, const Type *SrcTy,
   if (DstTy == SrcTy) return false;       // If already equal, noop
 
   // If we found our opaque type, resolve it now!
-  if (isa<OpaqueType>(DstTy) || isa<OpaqueType>(SrcTy))
+  if (DstTy->isOpaqueTy() || SrcTy->isOpaqueTy())
     return ResolveTypes(DstTy, SrcTy);
 
   // Two types cannot be resolved together if they are of different primitive
@@ -392,9 +392,20 @@ static Value *RemapOperand(const Value *In,
       assert(!isa<GlobalValue>(CPV) && "Unmapped global?");
       llvm_unreachable("Unknown type of derived type constant value!");
     }
-  } else if (isa<MetadataBase>(In)) {
-    Result = const_cast<Value*>(In);
-  } else if (isa<InlineAsm>(In)) {
+  } else if (const MDNode *MD = dyn_cast<MDNode>(In)) {
+    if (MD->isFunctionLocal()) {
+      SmallVector<Value*, 4> Elts;
+      for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
+        if (MD->getOperand(i))
+          Elts.push_back(RemapOperand(MD->getOperand(i), ValueMap));
+        else
+          Elts.push_back(NULL);
+      }
+      Result = MDNode::get(In->getContext(), Elts.data(), MD->getNumOperands());
+    } else {
+      Result = const_cast<Value*>(In);
+    }
+  } else if (isa<MDString>(In) || isa<InlineAsm>(In) || isa<Instruction>(In)) {
     Result = const_cast<Value*>(In);
   }
 
@@ -855,9 +866,14 @@ static bool LinkAlias(Module *Dest, const Module *Src,
     } else {
       // No linking to be performed, simply create an identical version of the
       // alias over in the dest module...
-
+      Constant *Aliasee = DAliasee;
+      // Fixup aliases to bitcasts.  Note that aliases to GEPs are still broken
+      // by this, but aliases to GEPs are broken to a lot of other things, so
+      // it's less important.
+      if (SGA->getType() != DAliasee->getType())
+        Aliasee = ConstantExpr::getBitCast(DAliasee, SGA->getType());
       NewGA = new GlobalAlias(SGA->getType(), SGA->getLinkage(),
-                              SGA->getName(), DAliasee, Dest);
+                              SGA->getName(), Aliasee, Dest);
       CopyGVAttributes(NewGA, SGA);
 
       // Proceed to 'common' steps
@@ -1223,9 +1239,15 @@ static bool LinkAppendingVars(Module *M,
 static bool ResolveAliases(Module *Dest) {
   for (Module::alias_iterator I = Dest->alias_begin(), E = Dest->alias_end();
        I != E; ++I)
-    if (const GlobalValue *GV = I->resolveAliasedGlobal())
-      if (GV != I && !GV->isDeclaration())
-        I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
+    // We can't sue resolveGlobalAlias here because we need to preserve
+    // bitcasts and GEPs.
+    if (const Constant *C = I->getAliasee()) {
+      while (dyn_cast<GlobalAlias>(C))
+        C = cast<GlobalAlias>(C)->getAliasee();
+      const GlobalValue *GV = dyn_cast<GlobalValue>(C);
+      if (C != I && !(GV && GV->isDeclaration()))
+        I->replaceAllUsesWith(const_cast<Constant*>(C));
+    }
 
   return false;
 }