1 //===- ExtractFunction.cpp - Extract a function from Program --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements several methods that are used to extract functions,
11 // loops, or portions of a module from the rest of the module.
13 //===----------------------------------------------------------------------===//
15 #include "BugDriver.h"
16 #include "llvm/Constants.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Module.h"
19 #include "llvm/PassManager.h"
20 #include "llvm/Pass.h"
21 #include "llvm/SymbolTable.h"
22 #include "llvm/Analysis/Verifier.h"
23 #include "llvm/Transforms/IPO.h"
24 #include "llvm/Transforms/Scalar.h"
25 #include "llvm/Transforms/Utils/Cloning.h"
26 #include "llvm/Transforms/Utils/FunctionUtils.h"
27 #include "llvm/Target/TargetData.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/FileUtilities.h"
36 bool DisableSimplifyCFG = false;
37 } // End llvm namespace
42 cl::desc("Do not use the -dce pass to reduce testcases"));
44 NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
45 cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
48 /// deleteInstructionFromProgram - This method clones the current Program and
49 /// deletes the specified instruction from the cloned module. It then runs a
50 /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
51 /// depends on the value. The modified module is then returned.
53 Module *BugDriver::deleteInstructionFromProgram(const Instruction *I,
54 unsigned Simplification) const {
55 Module *Result = CloneModule(Program);
57 const BasicBlock *PBB = I->getParent();
58 const Function *PF = PBB->getParent();
60 Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
61 std::advance(RFI, std::distance(PF->getParent()->begin(),
62 Module::const_iterator(PF)));
64 Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
65 std::advance(RBI, std::distance(PF->begin(), Function::const_iterator(PBB)));
67 BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
68 std::advance(RI, std::distance(PBB->begin(), BasicBlock::const_iterator(I)));
69 Instruction *TheInst = RI; // Got the corresponding instruction!
71 // If this instruction produces a value, replace any users with null values
72 if (TheInst->getType() != Type::VoidTy)
73 TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
75 // Remove the instruction from the program.
76 TheInst->getParent()->getInstList().erase(TheInst);
79 //writeProgramToFile("current.bc", Result);
81 // Spiff up the output a little bit.
83 // Make sure that the appropriate target data is always used...
84 Passes.add(new TargetData(Result));
86 /// FIXME: If this used runPasses() like the methods below, we could get rid
87 /// of the -disable-* options!
88 if (Simplification > 1 && !NoDCE)
89 Passes.add(createDeadCodeEliminationPass());
90 if (Simplification && !DisableSimplifyCFG)
91 Passes.add(createCFGSimplificationPass()); // Delete dead control flow
93 Passes.add(createVerifierPass());
98 static const PassInfo *getPI(Pass *P) {
99 const PassInfo *PI = P->getPassInfo();
104 /// performFinalCleanups - This method clones the current Program and performs
105 /// a series of cleanups intended to get rid of extra cruft on the module
106 /// before handing it to the user.
108 Module *BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
109 // Make all functions external, so GlobalDCE doesn't delete them...
110 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
111 I->setLinkage(GlobalValue::ExternalLinkage);
113 std::vector<const PassInfo*> CleanupPasses;
114 CleanupPasses.push_back(getPI(createFunctionResolvingPass()));
115 CleanupPasses.push_back(getPI(createGlobalDCEPass()));
116 CleanupPasses.push_back(getPI(createDeadTypeEliminationPass()));
118 if (MayModifySemantics)
119 CleanupPasses.push_back(getPI(createDeadArgHackingPass()));
121 CleanupPasses.push_back(getPI(createDeadArgEliminationPass()));
123 Module *New = runPassesOn(M, CleanupPasses);
125 std::cerr << "Final cleanups failed. Sorry. :( Please report a bug!\n";
133 /// ExtractLoop - Given a module, extract up to one loop from it into a new
134 /// function. This returns null if there are no extractable loops in the
135 /// program or if the loop extractor crashes.
136 Module *BugDriver::ExtractLoop(Module *M) {
137 std::vector<const PassInfo*> LoopExtractPasses;
138 LoopExtractPasses.push_back(getPI(createSingleLoopExtractorPass()));
140 Module *NewM = runPassesOn(M, LoopExtractPasses);
142 Module *Old = swapProgramIn(M);
143 std::cout << "*** Loop extraction failed: ";
144 EmitProgressBytecode("loopextraction", true);
145 std::cout << "*** Sorry. :( Please report a bug!\n";
150 // Check to see if we created any new functions. If not, no loops were
151 // extracted and we should return null. Limit the number of loops we extract
152 // to avoid taking forever.
153 static unsigned NumExtracted = 32;
154 if (M->size() == NewM->size() || --NumExtracted == 0) {
158 assert(M->size() < NewM->size() && "Loop extract removed functions?");
159 Module::iterator MI = NewM->begin();
160 for (unsigned i = 0, e = M->size(); i != e; ++i)
168 // DeleteFunctionBody - "Remove" the function by deleting all of its basic
169 // blocks, making it external.
171 void llvm::DeleteFunctionBody(Function *F) {
172 // delete the body of the function...
174 assert(F->isExternal() && "This didn't make the function external!");
177 /// GetTorInit - Given a list of entries for static ctors/dtors, return them
178 /// as a constant array.
179 static Constant *GetTorInit(std::vector<std::pair<Function*, int> > &TorList) {
180 assert(!TorList.empty() && "Don't create empty tor list!");
181 std::vector<Constant*> ArrayElts;
182 for (unsigned i = 0, e = TorList.size(); i != e; ++i) {
183 std::vector<Constant*> Elts;
184 Elts.push_back(ConstantSInt::get(Type::IntTy, TorList[i].second));
185 Elts.push_back(TorList[i].first);
186 ArrayElts.push_back(ConstantStruct::get(Elts));
188 return ConstantArray::get(ArrayType::get(ArrayElts[0]->getType(),
193 /// SplitStaticCtorDtor - A module was recently split into two parts, M1/M2, and
194 /// M1 has all of the global variables. If M2 contains any functions that are
195 /// static ctors/dtors, we need to add an llvm.global_[cd]tors global to M2, and
196 /// prune appropriate entries out of M1s list.
197 static void SplitStaticCtorDtor(const char *GlobalName, Module *M1, Module *M2){
198 GlobalVariable *GV = M1->getNamedGlobal(GlobalName);
199 if (!GV || GV->isExternal() || GV->hasInternalLinkage() ||
200 !GV->use_empty()) return;
202 std::vector<std::pair<Function*, int> > M1Tors, M2Tors;
203 ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
204 if (!InitList) return;
206 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
207 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
208 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
210 if (CS->getOperand(1)->isNullValue())
211 break; // Found a null terminator, stop here.
213 ConstantSInt *CI = dyn_cast<ConstantSInt>(CS->getOperand(0));
214 int Priority = CI ? CI->getValue() : 0;
216 Constant *FP = CS->getOperand(1);
217 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
218 if (CE->getOpcode() == Instruction::Cast)
219 FP = CE->getOperand(0);
220 if (Function *F = dyn_cast<Function>(FP)) {
221 if (!F->isExternal())
222 M1Tors.push_back(std::make_pair(F, Priority));
224 // Map to M2's version of the function.
225 F = M2->getFunction(F->getName(), F->getFunctionType());
226 M2Tors.push_back(std::make_pair(F, Priority));
232 GV->eraseFromParent();
233 if (!M1Tors.empty()) {
234 Constant *M1Init = GetTorInit(M1Tors);
235 new GlobalVariable(M1Init->getType(), false, GlobalValue::AppendingLinkage,
236 M1Init, GlobalName, M1);
239 GV = M2->getNamedGlobal(GlobalName);
240 assert(GV && "Not a clone of M1?");
241 assert(GV->use_empty() && "llvm.ctors shouldn't have uses!");
243 GV->eraseFromParent();
244 if (!M2Tors.empty()) {
245 Constant *M2Init = GetTorInit(M2Tors);
246 new GlobalVariable(M2Init->getType(), false, GlobalValue::AppendingLinkage,
247 M2Init, GlobalName, M2);
251 //// RewriteUsesInNewModule - takes a Module and a reference to a globalvalue
252 //// (OrigVal) in that module and changes the reference to a different
253 //// globalvalue (NewVal) in a seperate module.
254 static void RewriteUsesInNewModule(Constant *OrigVal, Constant *NewVal,
256 assert(OrigVal->getType() == NewVal->getType() &&
257 "Can't replace something with a different type");
258 for (Value::use_iterator UI = OrigVal->use_begin(), E = OrigVal->use_end();
260 Value::use_iterator TmpUI = UI++;
262 if (Instruction *Inst = dyn_cast<Instruction>(U)) {
263 Module *InstM = Inst->getParent()->getParent()->getParent();
264 if (InstM != TargetMod) {
265 TmpUI.getUse() = NewVal;
267 } else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(U)) {
268 if (GV->getParent() != TargetMod) {
269 TmpUI.getUse() = NewVal;
271 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) {
272 // If nothing uses this, don't bother making a copy.
273 if (CE->use_empty()) continue;
274 Constant *NewCE = CE->getWithOperandReplaced(TmpUI.getOperandNo(),
276 RewriteUsesInNewModule(CE, NewCE, TargetMod);
277 } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(U)) {
278 // If nothing uses this, don't bother making a copy.
279 if (CS->use_empty()) continue;
280 unsigned OpNo = TmpUI.getOperandNo();
281 std::vector<Constant*> Ops;
282 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i)
283 Ops.push_back(i == OpNo ? NewVal : CS->getOperand(i));
284 Constant *NewStruct = ConstantStruct::get(Ops);
285 RewriteUsesInNewModule(CS, NewStruct, TargetMod);
286 } else if (ConstantPacked *CP = dyn_cast<ConstantPacked>(U)) {
287 // If nothing uses this, don't bother making a copy.
288 if (CP->use_empty()) continue;
289 unsigned OpNo = TmpUI.getOperandNo();
290 std::vector<Constant*> Ops;
291 for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
292 Ops.push_back(i == OpNo ? NewVal : CP->getOperand(i));
293 Constant *NewPacked = ConstantPacked::get(Ops);
294 RewriteUsesInNewModule(CP, NewPacked, TargetMod);
295 } else if (ConstantArray *CA = dyn_cast<ConstantArray>(U)) {
296 // If nothing uses this, don't bother making a copy.
297 if (CA->use_empty()) continue;
298 unsigned OpNo = TmpUI.getOperandNo();
299 std::vector<Constant*> Ops;
300 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
301 Ops.push_back(i == OpNo ? NewVal : CA->getOperand(i));
303 Constant *NewArray = ConstantArray::get(CA->getType(), Ops);
304 RewriteUsesInNewModule(CA, NewArray, TargetMod);
306 assert(0 && "Unexpected user");
312 /// SplitFunctionsOutOfModule - Given a module and a list of functions in the
313 /// module, split the functions OUT of the specified module, and place them in
315 Module *llvm::SplitFunctionsOutOfModule(Module *M,
316 const std::vector<Function*> &F) {
317 // Make sure functions & globals are all external so that linkage
318 // between the two modules will work.
319 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
320 I->setLinkage(GlobalValue::ExternalLinkage);
321 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
323 I->setLinkage(GlobalValue::ExternalLinkage);
325 // First off, we need to create the new module...
326 Module *New = new Module(M->getModuleIdentifier());
327 New->setEndianness(M->getEndianness());
328 New->setPointerSize(M->getPointerSize());
329 New->setTargetTriple(M->getTargetTriple());
330 New->setModuleInlineAsm(M->getModuleInlineAsm());
332 // Copy all of the dependent libraries over.
333 for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
336 // build a set of the functions to search later...
337 std::set<std::pair<std::string, const PointerType*> > TestFunctions;
338 for (unsigned i = 0, e = F.size(); i != e; ++i) {
339 TestFunctions.insert(std::make_pair(F[i]->getName(), F[i]->getType()));
342 std::map<GlobalValue*, GlobalValue*> GlobalToPrototypeMap;
343 std::vector<GlobalValue*> OrigGlobals;
345 // Adding specified functions to new module...
346 for (Module::iterator I = M->begin(), E = M->end(); I != E;) {
347 OrigGlobals.push_back(I);
348 if(TestFunctions.count(std::make_pair(I->getName(), I->getType()))) {
349 Module::iterator tempI = I;
351 Function * func = new Function(tempI->getFunctionType(),
352 GlobalValue::ExternalLinkage);
353 M->getFunctionList().insert(tempI, func);
354 New->getFunctionList().splice(New->end(),
355 M->getFunctionList(),
357 func->setName(tempI->getName());
358 func->setCallingConv(tempI->getCallingConv());
359 GlobalToPrototypeMap[tempI] = func;
362 Function * func = new Function(I->getFunctionType(),
363 GlobalValue::ExternalLinkage,
366 func->setCallingConv(I->getCallingConv());
367 GlobalToPrototypeMap[I] = func;
373 //copy over global list
374 for (Module::global_iterator I = M->global_begin(),
375 E = M->global_end(); I != E; ++I) {
376 OrigGlobals.push_back(I);
377 GlobalVariable *glob = new GlobalVariable (I->getType()->getElementType(),
379 GlobalValue::ExternalLinkage,
383 GlobalToPrototypeMap[I] = glob;
386 // Copy all of the type symbol table entries over.
387 const SymbolTable &SymTab = M->getSymbolTable();
388 SymbolTable::type_const_iterator TypeI = SymTab.type_begin();
389 SymbolTable::type_const_iterator TypeE = SymTab.type_end();
390 for (; TypeI != TypeE; ++TypeI)
391 New->addTypeName(TypeI->first, TypeI->second);
393 // Loop over globals, rewriting uses in the module the prototype is in to use
395 for (unsigned i = 0, e = OrigGlobals.size(); i != e; ++i) {
396 assert(OrigGlobals[i]->getName() ==
397 GlobalToPrototypeMap[OrigGlobals[i]]->getName());
398 RewriteUsesInNewModule(OrigGlobals[i], GlobalToPrototypeMap[OrigGlobals[i]],
399 OrigGlobals[i]->getParent());
402 // Make sure that there is a global ctor/dtor array in both halves of the
403 // module if they both have static ctor/dtor functions.
404 SplitStaticCtorDtor("llvm.global_ctors", M, New);
405 SplitStaticCtorDtor("llvm.global_dtors", M, New);
410 //===----------------------------------------------------------------------===//
411 // Basic Block Extraction Code
412 //===----------------------------------------------------------------------===//
415 std::vector<BasicBlock*> BlocksToNotExtract;
417 /// BlockExtractorPass - This pass is used by bugpoint to extract all blocks
418 /// from the module into their own functions except for those specified by the
419 /// BlocksToNotExtract list.
420 class BlockExtractorPass : public ModulePass {
421 bool runOnModule(Module &M);
423 RegisterPass<BlockExtractorPass>
424 XX("extract-bbs", "Extract Basic Blocks From Module (for bugpoint use)");
427 bool BlockExtractorPass::runOnModule(Module &M) {
428 std::set<BasicBlock*> TranslatedBlocksToNotExtract;
429 for (unsigned i = 0, e = BlocksToNotExtract.size(); i != e; ++i) {
430 BasicBlock *BB = BlocksToNotExtract[i];
431 Function *F = BB->getParent();
433 // Map the corresponding function in this module.
434 Function *MF = M.getFunction(F->getName(), F->getFunctionType());
436 // Figure out which index the basic block is in its function.
437 Function::iterator BBI = MF->begin();
438 std::advance(BBI, std::distance(F->begin(), Function::iterator(BB)));
439 TranslatedBlocksToNotExtract.insert(BBI);
442 // Now that we know which blocks to not extract, figure out which ones we WANT
444 std::vector<BasicBlock*> BlocksToExtract;
445 for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
446 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
447 if (!TranslatedBlocksToNotExtract.count(BB))
448 BlocksToExtract.push_back(BB);
450 for (unsigned i = 0, e = BlocksToExtract.size(); i != e; ++i)
451 ExtractBasicBlock(BlocksToExtract[i]);
453 return !BlocksToExtract.empty();
456 /// ExtractMappedBlocksFromModule - Extract all but the specified basic blocks
457 /// into their own functions. The only detail is that M is actually a module
458 /// cloned from the one the BBs are in, so some mapping needs to be performed.
459 /// If this operation fails for some reason (ie the implementation is buggy),
460 /// this function should return null, otherwise it returns a new Module.
461 Module *BugDriver::ExtractMappedBlocksFromModule(const
462 std::vector<BasicBlock*> &BBs,
464 // Set the global list so that pass will be able to access it.
465 BlocksToNotExtract = BBs;
467 std::vector<const PassInfo*> PI;
468 PI.push_back(getPI(new BlockExtractorPass()));
469 Module *Ret = runPassesOn(M, PI);
470 BlocksToNotExtract.clear();
472 std::cout << "*** Basic Block extraction failed, please report a bug!\n";
473 M = swapProgramIn(M);
474 EmitProgressBytecode("basicblockextractfail", true);