In function mover, look up the global/function by name also

If there is both a declaration and a definition it can happen that the
function and the reference to it are copied seperately, hence we need
to check whether the name already exists. Otherwise LLVM will
deduplicate the name resulting in linking errors. We don't emit this
code pattern but it can happen when used with llvmcall.

src/cgutils.cpp

@@ -100,7 +100,7 @@ class FunctionMover : public ValueMaterializer
  ValueMaterializer(), VMap(), destModule(dest), srcModule(src)
  {
 
- } 
+ }
  ValueToValueMapTy VMap;
  llvm::Module *destModule;
  llvm::Module *srcModule;
@@ -118,12 +118,15 @@ class FunctionMover : public ValueMaterializer
  // Check whether we already emitted it once
  uint64_t addr = jl_mcjmm->getSymbolAddress(F->getName());
  if (addr == 0) {
+ Function *oldF = destModule->getFunction(F->getName());
+ if (oldF)
+ return oldF;
  return clone_llvm_function(shadow,this);
- } 
+ }
  else {
  return destModule->getOrInsertFunction(F->getName(),F->getFunctionType());
  }
- } 
+ }
  else if (!F->isDeclaration()) {
  return clone_llvm_function(F,this);
  }
@@ -133,10 +136,13 @@ class FunctionMover : public ValueMaterializer
  // Create forward declaration in current module
  return destModule->getOrInsertFunction(F->getName(),F->getFunctionType());
  }
- } 
+ }
  else if (isa<GlobalVariable>(V)) {
  GlobalVariable *GV = cast<GlobalVariable>(V);
  assert(GV != NULL);
+ GlobalVariable *oldGV = destModule->getGlobalVariable(GV->getName());
+ if (oldGV != NULL)
+ return oldGV;
  GlobalVariable *newGV = new GlobalVariable(*destModule,
  GV->getType()->getElementType(),
  GV->isConstant(),
@@ -156,7 +162,7 @@ class FunctionMover : public ValueMaterializer
  if (it != llvm_to_jl_value.end()) {
  newGV->setInitializer(Constant::getIntegerValue(GV->getType()->getElementType(),APInt(sizeof(void*)*8,(ptrint_t)it->second)));
  newGV->setConstant(true);
- } 
+ }
  else if (GV->hasInitializer()) {
  Value *C = MapValue(GV->getInitializer(),VMap,RF_None,NULL,this);
  newGV->setInitializer(cast<Constant>(C));