[llvm-commits] [llvm] r55997 - in /llvm/trunk: include/llvm/GlobalAlias.h lib/Linker/LinkModules.cpp lib/VMCore/Globals.cpp

[Anton Korobeynikov]

Author: asl
Date: Tue Sep  9 13:23:48 2008
New Revision: 55997

URL: http://llvm.org/viewvc/llvm-project?rev=55997&view=rev
Log:
Fix incorrect linker behaviour: we shouldn't resolve weak aliases.

Modified:
    llvm/trunk/include/llvm/GlobalAlias.h
    llvm/trunk/lib/Linker/LinkModules.cpp
    llvm/trunk/lib/VMCore/Globals.cpp

Modified: llvm/trunk/include/llvm/GlobalAlias.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/GlobalAlias.h?rev=55997&r1=55996&r2=55997&view=diff

==============================================================================
--- llvm/trunk/include/llvm/GlobalAlias.h (original)
+++ llvm/trunk/include/llvm/GlobalAlias.h Tue Sep  9 13:23:48 2008
@@ -76,8 +76,10 @@
 
   /// resolveAliasedGlobal() - This method tries to ultimately resolve the alias
   /// by going through the aliasing chain and trying to find the very last
-  /// global. Returns NULL if a cycle was found.
-  const GlobalValue* resolveAliasedGlobal() const;
+  /// global. Returns NULL if a cycle was found. If traverseWeak is true, then
+  /// the whole chain aliasing chain is traversed, otherwise - only strong
+  /// aliases.
+  const GlobalValue* resolveAliasedGlobal(bool traverseWeak = true) const;
 
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const GlobalAlias *) { return true; }

Modified: llvm/trunk/lib/Linker/LinkModules.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Linker/LinkModules.cpp?rev=55997&r1=55996&r2=55997&view=diff

==============================================================================
--- llvm/trunk/lib/Linker/LinkModules.cpp (original)
+++ llvm/trunk/lib/Linker/LinkModules.cpp Tue Sep  9 13:23:48 2008
@@ -1169,8 +1169,8 @@
 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->isDeclaration())
+    if (const GlobalValue *GV = I->resolveAliasedGlobal(/*traverseWeak*/ false))
+      if (GV != I && !GV->isDeclaration())
         I->replaceAllUsesWith(const_cast<GlobalValue*>(GV));
 
   return false;

Modified: llvm/trunk/lib/VMCore/Globals.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Globals.cpp?rev=55997&r1=55996&r2=55997&view=diff

==============================================================================
--- llvm/trunk/lib/VMCore/Globals.cpp (original)
+++ llvm/trunk/lib/VMCore/Globals.cpp Tue Sep  9 13:23:48 2008
@@ -248,13 +248,21 @@
   return 0;
 }
 
-const GlobalValue *GlobalAlias::resolveAliasedGlobal() const {
+const GlobalValue *GlobalAlias::resolveAliasedGlobal(bool traverseWeak) const {
   SmallPtrSet<const GlobalValue*, 3> Visited;
 
+  // Check if we need to stop early.
+  if (!traverseWeak && hasWeakLinkage())
+    return this;
+
   const GlobalValue *GV = getAliasedGlobal();
   Visited.insert(GV);
 
+  // Iterate over aliasing chain, stopping on weak alias if necessary.
   while (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV)) {
+    if (traverseWeak && GA->hasWeakLinkage())
+      break;
+
     GV = GA->getAliasedGlobal();
 
     if (!Visited.insert(GV))