void
Module::wrapSymbol(StringRef symName) {
std::string wrapSymName("__wrap_");
wrapSymName += symName;
std::string realSymName("__real_");
realSymName += symName;
GlobalValue *SymGV = getNamedValue(symName);
GlobalValue *WrapGV = getNamedValue(wrapSymName);
GlobalValue *RealGV = getNamedValue(realSymName);
// Replace uses of "sym" with __wrap_sym.
if (SymGV) {
if (!WrapGV)
WrapGV = cast<GlobalValue>(getOrInsertGlobal(wrapSymName,
SymGV->getType()));
SymGV->replaceAllUsesWith(ConstantExpr::getBitCast(WrapGV,
SymGV->getType()));
}
// Replace uses of "__real_sym" with "sym".
if (RealGV) {
if (!SymGV)
SymGV = cast<GlobalValue>(getOrInsertGlobal(symName, RealGV->getType()));
RealGV->replaceAllUsesWith(ConstantExpr::getBitCast(SymGV,
RealGV->getType()));
}
}
bool DefineExtsPass::runOnModule(Module& M) {
bool modified = false;
for(cl::list<std::string>::iterator it = NullSymbols.begin(), it2 = NullSymbols.end(); it != it2; ++it) {
GlobalValue* GV = M.getNamedValue(*it);
if(!GV) {
errs() << "Warning: skipped value " << *it << " (symbol not found)\n";
continue;
}
if(Function* F = dyn_cast<Function>(GV)) {
if(!F->isDeclaration()) {
errs() << "Warning: skipped function " << *it << " because it has a definition\n";
continue;
}
}
GV->replaceAllUsesWith(Constant::getNullValue(GV->getType()));
modified = true;
}
return modified;
}
/// linkFunctionProto - Link the function in the source module into the
/// destination module if needed, setting up mapping information.
bool ModuleLinker::linkFunctionProto(Function *SF) {
GlobalValue *DGV = getLinkedToGlobal(SF);
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
if (DGV) {
GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
bool LinkFromSrc = false;
GlobalValue::VisibilityTypes NV;
if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
return true;
NewVisibility = NV;
if (!LinkFromSrc) {
// Set calculated linkage
DGV->setLinkage(NewLinkage);
DGV->setVisibility(*NewVisibility);
// Make sure to remember this mapping.
ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
// Track the function from the source module so we don't attempt to remap
// it.
DoNotLinkFromSource.insert(SF);
return false;
}
}
// If there is no linkage to be performed or we are linking from the source,
// bring SF over.
Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
SF->getLinkage(), SF->getName(), DstM);
CopyGVAttributes(NewDF, SF);
if (NewVisibility)
NewDF->setVisibility(*NewVisibility);
if (DGV) {
// Any uses of DF need to change to NewDF, with cast.
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
DGV->eraseFromParent();
} else {
// Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link.
if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
SF->hasAvailableExternallyLinkage()) {
DoNotLinkFromSource.insert(SF);
LazilyLinkFunctions.push_back(SF);
}
}
ValueMap[SF] = NewDF;
return false;
}
/// LinkAliasProto - Set up prototypes for any aliases that come over from the
/// source module.
bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
GlobalValue *DGV = getLinkedToGlobal(SGA);
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
if (DGV) {
GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
GlobalValue::VisibilityTypes NV;
bool LinkFromSrc = false;
if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
return true;
NewVisibility = NV;
if (!LinkFromSrc) {
// Set calculated linkage.
DGV->setLinkage(NewLinkage);
DGV->setVisibility(*NewVisibility);
// Make sure to remember this mapping.
ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
// Track the alias from the source module so we don't attempt to remap it.
DoNotLinkFromSource.insert(SGA);
return false;
}
}
// If there is no linkage to be performed or we're linking from the source,
// bring over SGA.
GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
SGA->getLinkage(), SGA->getName(),
/*aliasee*/0, DstM);
CopyGVAttributes(NewDA, SGA);
if (NewVisibility)
NewDA->setVisibility(*NewVisibility);
if (DGV) {
// Any uses of DGV need to change to NewDA, with cast.
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType()));
DGV->eraseFromParent();
}
ValueMap[SGA] = NewDA;
return false;
}
// destructively move the contents of src into dest
// this assumes that the targets of the two modules are the same
// including the DataLayout and ModuleFlags (for example)
// and that there is no module-level assembly
static void jl_merge_module(Module *dest, std::unique_ptr<Module> src)
{
assert(dest != src.get());
for (Module::global_iterator I = src->global_begin(), E = src->global_end(); I != E;) {
GlobalVariable *sG = &*I;
GlobalValue *dG = dest->getNamedValue(sG->getName());
++I;
// Replace a declaration with the definition:
if (dG) {
if (sG->isDeclaration()) {
sG->replaceAllUsesWith(dG);
sG->eraseFromParent();
continue;
}
else {
dG->replaceAllUsesWith(sG);
dG->eraseFromParent();
}
}
// Reparent the global variable:
sG->removeFromParent();
dest->getGlobalList().push_back(sG);
// Comdat is owned by the Module, recreate it in the new parent:
addComdat(sG);
}
for (Module::iterator I = src->begin(), E = src->end(); I != E;) {
Function *sG = &*I;
GlobalValue *dG = dest->getNamedValue(sG->getName());
++I;
// Replace a declaration with the definition:
if (dG) {
if (sG->isDeclaration()) {
sG->replaceAllUsesWith(dG);
sG->eraseFromParent();
continue;
}
else {
dG->replaceAllUsesWith(sG);
dG->eraseFromParent();
}
}
// Reparent the global variable:
sG->removeFromParent();
dest->getFunctionList().push_back(sG);
// Comdat is owned by the Module, recreate it in the new parent:
addComdat(sG);
}
for (Module::alias_iterator I = src->alias_begin(), E = src->alias_end(); I != E;) {
GlobalAlias *sG = &*I;
GlobalValue *dG = dest->getNamedValue(sG->getName());
++I;
if (dG) {
if (!dG->isDeclaration()) { // aliases are always definitions, so this test is reversed from the above two
sG->replaceAllUsesWith(dG);
sG->eraseFromParent();
continue;
}
else {
dG->replaceAllUsesWith(sG);
dG->eraseFromParent();
}
}
sG->removeFromParent();
dest->getAliasList().push_back(sG);
}
// metadata nodes need to be explicitly merged not just copied
// so there are special passes here for each known type of metadata
NamedMDNode *sNMD = src->getNamedMetadata("llvm.dbg.cu");
if (sNMD) {
NamedMDNode *dNMD = dest->getOrInsertNamedMetadata("llvm.dbg.cu");
#ifdef LLVM35
for (NamedMDNode::op_iterator I = sNMD->op_begin(), E = sNMD->op_end(); I != E; ++I) {
dNMD->addOperand(*I);
}
#else
for (unsigned i = 0, l = sNMD->getNumOperands(); i < l; i++) {
dNMD->addOperand(sNMD->getOperand(i));
}
#endif
}
}
Expected<Constant *> IRLinker::linkGlobalValueProto(GlobalValue *SGV,
bool ForAlias) {
GlobalValue *DGV = getLinkedToGlobal(SGV);
bool ShouldLink = shouldLink(DGV, *SGV);
// just missing from map
if (ShouldLink) {
auto I = ValueMap.find(SGV);
if (I != ValueMap.end())
return cast<Constant>(I->second);
I = AliasValueMap.find(SGV);
if (I != AliasValueMap.end())
return cast<Constant>(I->second);
}
if (!ShouldLink && ForAlias)
DGV = nullptr;
// Handle the ultra special appending linkage case first.
assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage());
if (SGV->hasAppendingLinkage())
return linkAppendingVarProto(cast_or_null<GlobalVariable>(DGV),
cast<GlobalVariable>(SGV));
GlobalValue *NewGV;
if (DGV && !ShouldLink) {
NewGV = DGV;
} else {
// If we are done linking global value bodies (i.e. we are performing
// metadata linking), don't link in the global value due to this
// reference, simply map it to null.
if (DoneLinkingBodies)
return nullptr;
NewGV = copyGlobalValueProto(SGV, ShouldLink);
if (ShouldLink || !ForAlias)
forceRenaming(NewGV, SGV->getName());
}
// Overloaded intrinsics have overloaded types names as part of their
// names. If we renamed overloaded types we should rename the intrinsic
// as well.
if (Function *F = dyn_cast<Function>(NewGV))
if (auto Remangled = Intrinsic::remangleIntrinsicFunction(F))
NewGV = Remangled.getValue();
if (ShouldLink || ForAlias) {
if (const Comdat *SC = SGV->getComdat()) {
if (auto *GO = dyn_cast<GlobalObject>(NewGV)) {
Comdat *DC = DstM.getOrInsertComdat(SC->getName());
DC->setSelectionKind(SC->getSelectionKind());
GO->setComdat(DC);
}
}
}
if (!ShouldLink && ForAlias)
NewGV->setLinkage(GlobalValue::InternalLinkage);
Constant *C = NewGV;
if (DGV)
C = ConstantExpr::getBitCast(NewGV, TypeMap.get(SGV->getType()));
if (DGV && NewGV != DGV) {
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGV, DGV->getType()));
DGV->eraseFromParent();
}
return C;
}
// emit_alias_to_llvm - Given decl and target emit alias to target.
void emit_alias_to_llvm(tree decl, tree target, tree target_decl) {
if (errorcount || sorrycount) return;
timevar_push(TV_LLVM_GLOBALS);
// Get or create LLVM global for our alias.
GlobalValue *V = cast<GlobalValue>(DECL_LLVM(decl));
GlobalValue *Aliasee = NULL;
if (target_decl)
Aliasee = cast<GlobalValue>(DECL_LLVM(target_decl));
else {
// This is something insane. Probably only LTHUNKs can be here
// Try to grab decl from IDENTIFIER_NODE
// Query SymTab for aliasee
const char* AliaseeName = IDENTIFIER_POINTER(target);
Aliasee =
dyn_cast_or_null<GlobalValue>(TheModule->
getValueSymbolTable().lookup(AliaseeName));
// Last resort. Query for name set via __asm__
if (!Aliasee) {
std::string starred = std::string("\001") + AliaseeName;
Aliasee =
dyn_cast_or_null<GlobalValue>(TheModule->
getValueSymbolTable().lookup(starred));
}
if (!Aliasee) {
error ("%J%qD aliased to undefined symbol %qE",
decl, decl, target);
timevar_pop(TV_LLVM_GLOBALS);
return;
}
}
GlobalValue::LinkageTypes Linkage;
// Check for external weak linkage
if (DECL_EXTERNAL(decl) && DECL_WEAK(decl))
Linkage = GlobalValue::WeakLinkage;
else if (!TREE_PUBLIC(decl))
Linkage = GlobalValue::InternalLinkage;
else
Linkage = GlobalValue::ExternalLinkage;
GlobalAlias* GA = new GlobalAlias(Aliasee->getType(), Linkage, "",
Aliasee, TheModule);
// Handle visibility style
if (TREE_PUBLIC(decl)) {
if (DECL_VISIBILITY(decl) == VISIBILITY_HIDDEN)
GA->setVisibility(GlobalValue::HiddenVisibility);
else if (DECL_VISIBILITY(decl) == VISIBILITY_PROTECTED)
GA->setVisibility(GlobalValue::ProtectedVisibility);
}
if (V->getType() == GA->getType())
V->replaceAllUsesWith(GA);
else if (!V->use_empty()) {
error ("%J Alias %qD used with invalid type!", decl, decl);
timevar_pop(TV_LLVM_GLOBALS);
return;
}
changeLLVMValue(V, GA);
GA->takeName(V);
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
GV->eraseFromParent();
else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
GA->eraseFromParent();
else if (Function *F = dyn_cast<Function>(V))
F->eraseFromParent();
else
assert(0 && "Unsuported global value");
TREE_ASM_WRITTEN(decl) = 1;
timevar_pop(TV_LLVM_GLOBALS);
return;
}
/// linkGlobalProto - Loop through the global variables in the src module and
/// merge them into the dest module.
bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
GlobalValue *DGV = getLinkedToGlobal(SGV);
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
if (DGV) {
// Concatenation of appending linkage variables is magic and handled later.
if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
// Determine whether linkage of these two globals follows the source
// module's definition or the destination module's definition.
GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
GlobalValue::VisibilityTypes NV;
bool LinkFromSrc = false;
if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
return true;
NewVisibility = NV;
// If we're not linking from the source, then keep the definition that we
// have.
if (!LinkFromSrc) {
// Special case for const propagation.
if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
DGVar->setConstant(true);
// Set calculated linkage and visibility.
DGV->setLinkage(NewLinkage);
DGV->setVisibility(*NewVisibility);
// Make sure to remember this mapping.
ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
// Track the source global so that we don't attempt to copy it over when
// processing global initializers.
DoNotLinkFromSource.insert(SGV);
return false;
}
}
// No linking to be performed or linking from the source: simply create an
// identical version of the symbol over in the dest module... the
// initializer will be filled in later by LinkGlobalInits.
GlobalVariable *NewDGV =
new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
SGV->isConstant(), SGV->getLinkage(), /*init*/0,
SGV->getName(), /*insertbefore*/0,
SGV->isThreadLocal(),
SGV->getType()->getAddressSpace());
// Propagate alignment, visibility and section info.
CopyGVAttributes(NewDGV, SGV);
if (NewVisibility)
NewDGV->setVisibility(*NewVisibility);
if (DGV) {
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
DGV->eraseFromParent();
}
// Make sure to remember this mapping.
ValueMap[SGV] = NewDGV;
return false;
}
