//
//===----------------------------------------------------------------------===//
-#include "llvm/Instructions.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/Constants.h"
#include "llvm/Transforms/IPO.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
#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 VISIBILITY_HIDDEN GVExtractorPass : public ModulePass {
- std::vector<GlobalValue*> Named;
+ class GVExtractorPass : public ModulePass {
+ SetVector<GlobalValue *> Named;
bool deleteStuff;
- bool reLink;
public:
static char ID; // Pass identification, replacement for typeid
/// specified function. Otherwise, it deletes as much of the module as
/// possible, except for the function specified.
///
- explicit GVExtractorPass(std::vector<GlobalValue*>& GVs, bool deleteS = true,
- bool relinkCallees = false)
- : ModulePass(&ID), Named(GVs), deleteStuff(deleteS),
- reLink(relinkCallees) {}
-
- bool runOnModule(Module &M) {
- if (Named.size() == 0) {
- return false; // Nothing to extract
- }
-
- if (deleteStuff)
- return deleteGV();
- M.setModuleInlineAsm("");
- return isolateGV(M);
- }
-
- bool deleteGV() {
- for (std::vector<GlobalValue*>::iterator GI = Named.begin(),
- GE = Named.end(); GI != GE; ++GI) {
- if (Function* NamedFunc = dyn_cast<Function>(*GI)) {
- // If we're in relinking mode, set linkage of all internal callees to
- // external. This will allow us extract function, and then - link
- // everything together
- if (reLink) {
- for (Function::iterator B = NamedFunc->begin(), BE = NamedFunc->end();
- B != BE; ++B) {
- for (BasicBlock::iterator I = B->begin(), E = B->end();
- I != E; ++I) {
- if (CallInst* callInst = dyn_cast<CallInst>(&*I)) {
- Function* Callee = callInst->getCalledFunction();
- if (Callee && Callee->hasLocalLinkage())
- Callee->setLinkage(GlobalValue::ExternalLinkage);
- }
- }
- }
- }
-
- NamedFunc->setLinkage(GlobalValue::ExternalLinkage);
- NamedFunc->deleteBody();
- assert(NamedFunc->isDeclaration() && "This didn't make the function external!");
- } else {
- if (!(*GI)->isDeclaration()) {
- cast<GlobalVariable>(*GI)->setInitializer(0); //clear the initializer
- (*GI)->setLinkage(GlobalValue::ExternalLinkage);
- }
+ explicit GVExtractorPass(std::vector<GlobalValue*>& GVs, bool deleteS = true)
+ : ModulePass(ID), Named(GVs.begin(), GVs.end()), deleteStuff(deleteS) {}
+
+ bool runOnModule(Module &M) override {
+ // Visit the global inline asm.
+ if (!deleteStuff)
+ M.setModuleInlineAsm("");
+
+ // For simplicity, just give all GlobalValues ExternalLinkage. A trickier
+ // implementation could figure out which GlobalValues are actually
+ // referenced by the Named set, and which GlobalValues in the rest of
+ // the module are referenced by the NamedSet, and get away with leaving
+ // more internal and private things internal and private. But for now,
+ // be conservative and simple.
+
+ // Visit the GlobalVariables.
+ for (Module::global_iterator I = M.global_begin(), E = M.global_end();
+ I != E; ++I) {
+ bool Delete =
+ deleteStuff == (bool)Named.count(I) && !I->isDeclaration();
+ if (!Delete) {
+ if (I->hasAvailableExternallyLinkage())
+ continue;
+ if (I->getName() == "llvm.global_ctors")
+ continue;
}
- }
- return true;
- }
- bool isolateGV(Module &M) {
- // Mark all globals internal
- // FIXME: what should we do with private linkage?
- for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
- if (!I->isDeclaration()) {
- I->setLinkage(GlobalValue::InternalLinkage);
- }
- for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
- if (!I->isDeclaration()) {
- I->setLinkage(GlobalValue::InternalLinkage);
- }
+ makeVisible(*I, Delete);
- // Make sure our result is globally accessible...
- // by putting them in the used array
- {
- std::vector<Constant *> AUGs;
- const Type *SBP= Context->getPointerTypeUnqual(Type::Int8Ty);
- for (std::vector<GlobalValue*>::iterator GI = Named.begin(),
- GE = Named.end(); GI != GE; ++GI) {
- (*GI)->setLinkage(GlobalValue::ExternalLinkage);
- AUGs.push_back(Context->getConstantExprBitCast(*GI, SBP));
- }
- ArrayType *AT = Context->getArrayType(SBP, AUGs.size());
- Constant *Init = Context->getConstantArray(AT, AUGs);
- GlobalValue *gv = new GlobalVariable(M.getContext(), AT, false,
- GlobalValue::AppendingLinkage,
- Init, "llvm.used", &M);
- gv->setSection("llvm.metadata");
+ if (Delete)
+ I->setInitializer(nullptr);
}
- // All of the functions may be used by global variables or the named
- // globals. Loop through them and create a new, external functions that
- // can be "used", instead of ones with bodies.
- std::vector<Function*> NewFunctions;
-
- Function *Last = --M.end(); // Figure out where the last real fn is.
-
- for (Module::iterator I = M.begin(); ; ++I) {
- if (std::find(Named.begin(), Named.end(), &*I) == Named.end()) {
- Function *New = Function::Create(I->getFunctionType(),
- GlobalValue::ExternalLinkage);
- New->copyAttributesFrom(I);
-
- // If it's not the named function, delete the body of the function
- I->dropAllReferences();
-
- M.getFunctionList().push_back(New);
- NewFunctions.push_back(New);
- New->takeName(I);
+ // Visit the Functions.
+ for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
+ bool Delete =
+ deleteStuff == (bool)Named.count(I) && !I->isDeclaration();
+ if (!Delete) {
+ if (I->hasAvailableExternallyLinkage())
+ continue;
}
- if (&*I == Last) break; // Stop after processing the last function
+ makeVisible(*I, Delete);
+
+ if (Delete)
+ I->deleteBody();
}
- // Now that we have replacements all set up, loop through the module,
- // deleting the old functions, replacing them with the newly created
- // functions.
- if (!NewFunctions.empty()) {
- unsigned FuncNum = 0;
- Module::iterator I = M.begin();
- do {
- if (std::find(Named.begin(), Named.end(), &*I) == Named.end()) {
- // Make everything that uses the old function use the new dummy fn
- I->replaceAllUsesWith(NewFunctions[FuncNum++]);
+ // Visit the Aliases.
+ for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end();
+ I != E;) {
+ Module::alias_iterator CurI = I;
+ ++I;
+
+ bool Delete = deleteStuff == (bool)Named.count(CurI);
+ makeVisible(*CurI, Delete);
- Function *Old = I;
- ++I; // Move the iterator to the new function
+ if (Delete) {
+ Type *Ty = CurI->getType()->getElementType();
- // Delete the old function!
- M.getFunctionList().erase(Old);
+ CurI->removeFromParent();
+ llvm::Value *Declaration;
+ if (FunctionType *FTy = dyn_cast<FunctionType>(Ty)) {
+ Declaration = Function::Create(FTy, GlobalValue::ExternalLinkage,
+ CurI->getName(), &M);
} else {
- ++I; // Skip the function we are extracting
+ Declaration =
+ new GlobalVariable(M, Ty, false, GlobalValue::ExternalLinkage,
+ nullptr, CurI->getName());
+
}
- } while (&*I != NewFunctions[0]);
+ CurI->replaceAllUsesWith(Declaration);
+ delete CurI;
+ }
}
return true;
char GVExtractorPass::ID = 0;
}
-ModulePass *llvm::createGVExtractionPass(std::vector<GlobalValue*>& GVs,
- bool deleteFn, bool relinkCallees) {
- return new GVExtractorPass(GVs, deleteFn, relinkCallees);
+ModulePass *llvm::createGVExtractionPass(std::vector<GlobalValue *> &GVs,
+ bool deleteFn) {
+ return new GVExtractorPass(GVs, deleteFn);
}
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