#include <algorithm>
using namespace llvm;
+/// Make sure GV is visible from both modules. Delete is true if it is
+/// being deleted from this module.
+/// This also makes sure GV cannot be dropped so that references from
+/// the split module remain valid.
+static void makeVisible(GlobalValue &GV, bool Delete) {
+ bool Local = GV.hasLocalLinkage();
+ if (Local || Delete) {
+ GV.setLinkage(GlobalValue::ExternalLinkage);
+ if (Local)
+ GV.setVisibility(GlobalValue::HiddenVisibility);
+ return;
+ }
+
+ if (!GV.hasLinkOnceLinkage()) {
+ assert(!GV.isDiscardableIfUnused());
+ return;
+ }
+
+ // Map linkonce* to weak* so that llvm doesn't drop this GV.
+ switch(GV.getLinkage()) {
+ default:
+ llvm_unreachable("Unexpected linkage");
+ case GlobalValue::LinkOnceAnyLinkage:
+ GV.setLinkage(GlobalValue::WeakAnyLinkage);
+ return;
+ case GlobalValue::LinkOnceODRLinkage:
+ GV.setLinkage(GlobalValue::WeakODRLinkage);
+ return;
+ }
+}
+
namespace {
/// @brief A pass to extract specific functions and their dependencies.
class GVExtractorPass : public ModulePass {
explicit GVExtractorPass(std::vector<GlobalValue*>& GVs, bool deleteS = true)
: ModulePass(ID), Named(GVs.begin(), GVs.end()), deleteStuff(deleteS) {}
- bool runOnModule(Module &M) {
+ bool runOnModule(Module &M) override {
// Visit the global inline asm.
if (!deleteStuff)
M.setModuleInlineAsm("");
continue;
}
- bool Local = I->isDiscardableIfUnused();
- if (Local)
- I->setVisibility(GlobalValue::HiddenVisibility);
-
- if (Local || Delete)
- I->setLinkage(GlobalValue::ExternalLinkage);
+ makeVisible(*I, Delete);
if (Delete)
- I->setInitializer(0);
+ I->setInitializer(nullptr);
}
// Visit the Functions.
continue;
}
- bool Local = I->isDiscardableIfUnused();
- if (Local)
- I->setVisibility(GlobalValue::HiddenVisibility);
-
- if (Local || Delete)
- I->setLinkage(GlobalValue::ExternalLinkage);
+ makeVisible(*I, Delete);
if (Delete)
I->deleteBody();
Module::alias_iterator CurI = I;
++I;
- if (CurI->isDiscardableIfUnused()) {
- CurI->setVisibility(GlobalValue::HiddenVisibility);
- CurI->setLinkage(GlobalValue::ExternalLinkage);
- }
+ bool Delete = deleteStuff == (bool)Named.count(CurI);
+ makeVisible(*CurI, Delete);
- if (deleteStuff == (bool)Named.count(CurI)) {
+ if (Delete) {
Type *Ty = CurI->getType()->getElementType();
CurI->removeFromParent();
} else {
Declaration =
new GlobalVariable(M, Ty, false, GlobalValue::ExternalLinkage,
- 0, CurI->getName());
+ nullptr, CurI->getName());
}
CurI->replaceAllUsesWith(Declaration);
char GVExtractorPass::ID = 0;
}
-ModulePass *llvm::createGVExtractionPass(std::vector<GlobalValue*>& GVs,
+ModulePass *llvm::createGVExtractionPass(std::vector<GlobalValue *> &GVs,
bool deleteFn) {
return new GVExtractorPass(GVs, deleteFn);
}