1 files changed, 75 insertions, 33 deletions

diff --git a/tools/lto/LTOCodeGenerator.cpp b/tools/lto/LTOCodeGenerator.cpp
index f72fdb0fca..6739e06767 100644
--- a/tools/lto/LTOCodeGenerator.cpp
+++ b/tools/lto/LTOCodeGenerator.cpp
@@ -75,7 +75,6 @@ LTOCodeGenerator::LTOCodeGenerator()
 {
     InitializeAllTargets();
     InitializeAllAsmPrinters();
-    InitializeAllAsmParsers();
 }
 
 LTOCodeGenerator::~LTOCodeGenerator()
@@ -88,7 +87,13 @@ LTOCodeGenerator::~LTOCodeGenerator()
 
 bool LTOCodeGenerator::addModule(LTOModule* mod, std::string& errMsg)
 {
-    return _linker.LinkInModule(mod->getLLVVMModule(), &errMsg);
+  bool ret = _linker.LinkInModule(mod->getLLVVMModule(), &errMsg);
+
+  const std::vector<const char*> &undefs = mod->getAsmUndefinedRefs();
+  for (int i = 0, e = undefs.size(); i != e; ++i)
+    _asmUndefinedRefs[undefs[i]] = 1;
+
+  return ret;
 }
     
 
@@ -249,6 +254,34 @@ bool LTOCodeGenerator::determineTarget(std::string& errMsg)
     return false;
 }
 
+void LTOCodeGenerator::applyRestriction(GlobalValue &GV,
+                                     std::vector<const char*> &mustPreserveList,
+                                        SmallPtrSet<GlobalValue*, 8> &asmUsed,
+                                        Mangler &mangler) {
+  SmallString<64> Buffer;
+  mangler.getNameWithPrefix(Buffer, &GV, false);
+
+  if (GV.isDeclaration())
+    return;
+  if (_mustPreserveSymbols.count(Buffer))
+    mustPreserveList.push_back(GV.getName().data());
+  if (_asmUndefinedRefs.count(Buffer))
+    asmUsed.insert(&GV);
+}
+
+static void findUsedValues(GlobalVariable *LLVMUsed,
+                           SmallPtrSet<GlobalValue*, 8> &UsedValues) {
+  if (LLVMUsed == 0) return;
+
+  ConstantArray *Inits = dyn_cast<ConstantArray>(LLVMUsed->getInitializer());
+  if (Inits == 0) return;
+
+  for (unsigned i = 0, e = Inits->getNumOperands(); i != e; ++i)
+    if (GlobalValue *GV = 
+          dyn_cast<GlobalValue>(Inits->getOperand(i)->stripPointerCasts()))
+      UsedValues.insert(GV);
+}
+
 void LTOCodeGenerator::applyScopeRestrictions() {
   if (_scopeRestrictionsDone) return;
   Module *mergedModule = _linker.getModule();
@@ -258,38 +291,47 @@ void LTOCodeGenerator::applyScopeRestrictions() {
   passes.add(createVerifierPass());
 
   // mark which symbols can not be internalized 
-  if (!_mustPreserveSymbols.empty()) {
-    MCContext Context(*_target->getMCAsmInfo(), NULL);
-    Mangler mangler(Context, *_target->getTargetData());
-    std::vector<const char*> mustPreserveList;
-    SmallString<64> Buffer;
-    for (Module::iterator f = mergedModule->begin(),
-         e = mergedModule->end(); f != e; ++f) {
-      Buffer.clear();
-      mangler.getNameWithPrefix(Buffer, f, false);
-      if (!f->isDeclaration() &&
-          _mustPreserveSymbols.count(Buffer))
-        mustPreserveList.push_back(f->getName().data());
-    }
-    for (Module::global_iterator v = mergedModule->global_begin(), 
-         e = mergedModule->global_end(); v !=  e; ++v) {
-      Buffer.clear();
-      mangler.getNameWithPrefix(Buffer, v, false);
-      if (!v->isDeclaration() &&
-          _mustPreserveSymbols.count(Buffer))
-        mustPreserveList.push_back(v->getName().data());
-    }
-    for (Module::alias_iterator a = mergedModule->alias_begin(),
-         e = mergedModule->alias_end(); a != e; ++a) {
-      Buffer.clear();
-      mangler.getNameWithPrefix(Buffer, a, false);
-      if (!a->isDeclaration() &&
-          _mustPreserveSymbols.count(Buffer))
-        mustPreserveList.push_back(a->getName().data());
-    }
-    passes.add(createInternalizePass(mustPreserveList));
+  MCContext Context(*_target->getMCAsmInfo(), NULL);
+  Mangler mangler(Context, *_target->getTargetData());
+  std::vector<const char*> mustPreserveList;
+  SmallPtrSet<GlobalValue*, 8> asmUsed;
+
+  for (Module::iterator f = mergedModule->begin(),
+         e = mergedModule->end(); f != e; ++f)
+    applyRestriction(*f, mustPreserveList, asmUsed, mangler);
+  for (Module::global_iterator v = mergedModule->global_begin(), 
+         e = mergedModule->global_end(); v !=  e; ++v)
+    applyRestriction(*v, mustPreserveList, asmUsed, mangler);
+  for (Module::alias_iterator a = mergedModule->alias_begin(),
+         e = mergedModule->alias_end(); a != e; ++a)
+    applyRestriction(*a, mustPreserveList, asmUsed, mangler);
+
+  GlobalVariable *LLVMCompilerUsed =
+    mergedModule->getGlobalVariable("llvm.compiler.used");
+  findUsedValues(LLVMCompilerUsed, asmUsed);
+  if (LLVMCompilerUsed)
+    LLVMCompilerUsed->eraseFromParent();
+
+  const llvm::Type *i8PTy = llvm::Type::getInt8PtrTy(_context);
+  std::vector<Constant*> asmUsed2;
+  for (SmallPtrSet<GlobalValue*, 16>::const_iterator i = asmUsed.begin(),
+         e = asmUsed.end(); i !=e; ++i) {
+    GlobalValue *GV = *i;
+    Constant *c = ConstantExpr::getBitCast(GV, i8PTy);
+    asmUsed2.push_back(c);
   }
-  
+
+  llvm::ArrayType *ATy = llvm::ArrayType::get(i8PTy, asmUsed2.size());
+  LLVMCompilerUsed =
+    new llvm::GlobalVariable(*mergedModule, ATy, false,
+                             llvm::GlobalValue::AppendingLinkage,
+                             llvm::ConstantArray::get(ATy, asmUsed2),
+                             "llvm.compiler.used");
+
+  LLVMCompilerUsed->setSection("llvm.metadata");
+
+  passes.add(createInternalizePass(mustPreserveList));
+
   // apply scope restrictions
   passes.run(*mergedModule);