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/Analysis/Verifier.h"
22 #include "llvm/Transforms/IPO.h"
23 #include "llvm/Transforms/Scalar.h"
24 #include "llvm/Transforms/Utils/Cloning.h"
25 #include "llvm/Transforms/Utils/FunctionUtils.h"
26 #include "llvm/Target/TargetData.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/FileUtilities.h"
30 #include "llvm/System/Path.h"
31 #include "llvm/System/Signals.h"
38 bool DisableSimplifyCFG = false;
39 } // End llvm namespace
44 cl::desc("Do not use the -dce pass to reduce testcases"));
46 NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
47 cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
50 /// deleteInstructionFromProgram - This method clones the current Program and
51 /// deletes the specified instruction from the cloned module. It then runs a
52 /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
53 /// depends on the value. The modified module is then returned.
55 Module *BugDriver::deleteInstructionFromProgram(const Instruction *I,
56 unsigned Simplification) const {
57 Module *Result = CloneModule(Program);
59 const BasicBlock *PBB = I->getParent();
60 const Function *PF = PBB->getParent();
62 Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
63 std::advance(RFI, std::distance(PF->getParent()->begin(),
64 Module::const_iterator(PF)));
66 Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
67 std::advance(RBI, std::distance(PF->begin(), Function::const_iterator(PBB)));
69 BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
70 std::advance(RI, std::distance(PBB->begin(), BasicBlock::const_iterator(I)));
71 Instruction *TheInst = RI; // Got the corresponding instruction!
73 // If this instruction produces a value, replace any users with null values
74 if (TheInst->getType() != Type::VoidTy)
75 TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
77 // Remove the instruction from the program.
78 TheInst->getParent()->getInstList().erase(TheInst);
81 //writeProgramToFile("current.bc", Result);
83 // Spiff up the output a little bit.
85 // Make sure that the appropriate target data is always used...
86 Passes.add(new TargetData(Result));
88 /// FIXME: If this used runPasses() like the methods below, we could get rid
89 /// of the -disable-* options!
90 if (Simplification > 1 && !NoDCE)
91 Passes.add(createDeadCodeEliminationPass());
92 if (Simplification && !DisableSimplifyCFG)
93 Passes.add(createCFGSimplificationPass()); // Delete dead control flow
95 Passes.add(createVerifierPass());
100 static const PassInfo *getPI(Pass *P) {
101 const PassInfo *PI = P->getPassInfo();
106 /// performFinalCleanups - This method clones the current Program and performs
107 /// a series of cleanups intended to get rid of extra cruft on the module
108 /// before handing it to the user.
110 Module *BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
111 // Make all functions external, so GlobalDCE doesn't delete them...
112 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
113 I->setLinkage(GlobalValue::ExternalLinkage);
115 std::vector<const PassInfo*> CleanupPasses;
116 CleanupPasses.push_back(getPI(createGlobalDCEPass()));
117 CleanupPasses.push_back(getPI(createDeadTypeEliminationPass()));
119 if (MayModifySemantics)
120 CleanupPasses.push_back(getPI(createDeadArgHackingPass()));
122 CleanupPasses.push_back(getPI(createDeadArgEliminationPass()));
124 Module *New = runPassesOn(M, CleanupPasses);
126 std::cerr << "Final cleanups failed. Sorry. :( Please report a bug!\n";
134 /// ExtractLoop - Given a module, extract up to one loop from it into a new
135 /// function. This returns null if there are no extractable loops in the
136 /// program or if the loop extractor crashes.
137 Module *BugDriver::ExtractLoop(Module *M) {
138 std::vector<const PassInfo*> LoopExtractPasses;
139 LoopExtractPasses.push_back(getPI(createSingleLoopExtractorPass()));
141 Module *NewM = runPassesOn(M, LoopExtractPasses);
143 Module *Old = swapProgramIn(M);
144 std::cout << "*** Loop extraction failed: ";
145 EmitProgressBitcode("loopextraction", true);
146 std::cout << "*** Sorry. :( Please report a bug!\n";
151 // Check to see if we created any new functions. If not, no loops were
152 // extracted and we should return null. Limit the number of loops we extract
153 // to avoid taking forever.
154 static unsigned NumExtracted = 32;
155 if (M->size() == NewM->size() || --NumExtracted == 0) {
159 assert(M->size() < NewM->size() && "Loop extract removed functions?");
160 Module::iterator MI = NewM->begin();
161 for (unsigned i = 0, e = M->size(); i != e; ++i)
169 // DeleteFunctionBody - "Remove" the function by deleting all of its basic
170 // blocks, making it external.
172 void llvm::DeleteFunctionBody(Function *F) {
173 // delete the body of the function...
175 assert(F->isDeclaration() && "This didn't make the function external!");
178 /// GetTorInit - Given a list of entries for static ctors/dtors, return them
179 /// as a constant array.
180 static Constant *GetTorInit(std::vector<std::pair<Function*, int> > &TorList) {
181 assert(!TorList.empty() && "Don't create empty tor list!");
182 std::vector<Constant*> ArrayElts;
183 for (unsigned i = 0, e = TorList.size(); i != e; ++i) {
184 std::vector<Constant*> Elts;
185 Elts.push_back(ConstantInt::get(Type::Int32Ty, TorList[i].second));
186 Elts.push_back(TorList[i].first);
187 ArrayElts.push_back(ConstantStruct::get(Elts));
189 return ConstantArray::get(ArrayType::get(ArrayElts[0]->getType(),
194 /// SplitStaticCtorDtor - A module was recently split into two parts, M1/M2, and
195 /// M1 has all of the global variables. If M2 contains any functions that are
196 /// static ctors/dtors, we need to add an llvm.global_[cd]tors global to M2, and
197 /// prune appropriate entries out of M1s list.
198 static void SplitStaticCtorDtor(const char *GlobalName, Module *M1, Module *M2){
199 GlobalVariable *GV = M1->getNamedGlobal(GlobalName);
200 if (!GV || GV->isDeclaration() || GV->hasInternalLinkage() ||
201 !GV->use_empty()) return;
203 std::vector<std::pair<Function*, int> > M1Tors, M2Tors;
204 ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
205 if (!InitList) return;
207 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
208 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
209 if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
211 if (CS->getOperand(1)->isNullValue())
212 break; // Found a null terminator, stop here.
214 ConstantInt *CI = dyn_cast<ConstantInt>(CS->getOperand(0));
215 int Priority = CI ? CI->getSExtValue() : 0;
217 Constant *FP = CS->getOperand(1);
218 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
220 FP = CE->getOperand(0);
221 if (Function *F = dyn_cast<Function>(FP)) {
222 if (!F->isDeclaration())
223 M1Tors.push_back(std::make_pair(F, Priority));
225 // Map to M2's version of the function.
226 F = M2->getFunction(F->getName());
227 M2Tors.push_back(std::make_pair(F, Priority));
233 GV->eraseFromParent();
234 if (!M1Tors.empty()) {
235 Constant *M1Init = GetTorInit(M1Tors);
236 new GlobalVariable(M1Init->getType(), false, GlobalValue::AppendingLinkage,
237 M1Init, GlobalName, M1);
240 GV = M2->getNamedGlobal(GlobalName);
241 assert(GV && "Not a clone of M1?");
242 assert(GV->use_empty() && "llvm.ctors shouldn't have uses!");
244 GV->eraseFromParent();
245 if (!M2Tors.empty()) {
246 Constant *M2Init = GetTorInit(M2Tors);
247 new GlobalVariable(M2Init->getType(), false, GlobalValue::AppendingLinkage,
248 M2Init, GlobalName, M2);
253 /// SplitFunctionsOutOfModule - Given a module and a list of functions in the
254 /// module, split the functions OUT of the specified module, and place them in
256 Module *llvm::SplitFunctionsOutOfModule(Module *M,
257 const std::vector<Function*> &F) {
258 // Make sure functions & globals are all external so that linkage
259 // between the two modules will work.
260 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
261 I->setLinkage(GlobalValue::ExternalLinkage);
262 for (Module::global_iterator I = M->global_begin(), E = M->global_end();
264 I->setLinkage(GlobalValue::ExternalLinkage);
266 Module *New = CloneModule(M);
268 // Make sure global initializers exist only in the safe module (CBE->.so)
269 for (Module::global_iterator I = New->global_begin(), E = New->global_end();
271 I->setInitializer(0); // Delete the initializer to make it external
273 // Remove the Test functions from the Safe module
274 std::set<std::pair<std::string, const PointerType*> > TestFunctions;
275 for (unsigned i = 0, e = F.size(); i != e; ++i) {
276 TestFunctions.insert(std::make_pair(F[i]->getName(), F[i]->getType()));
277 Function *TNOF = M->getFunction(F[i]->getName());
278 assert(TNOF && "Function doesn't exist in module!");
279 assert(TNOF->getFunctionType() == F[i]->getFunctionType() && "wrong type?");
280 DEBUG(std::cerr << "Removing function " << F[i]->getName() << "\n");
281 DeleteFunctionBody(TNOF); // Function is now external in this module!
285 // Remove the Safe functions from the Test module
286 for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I)
287 if (!TestFunctions.count(std::make_pair(I->getName(), I->getType())))
288 DeleteFunctionBody(I);
291 // Make sure that there is a global ctor/dtor array in both halves of the
292 // module if they both have static ctor/dtor functions.
293 SplitStaticCtorDtor("llvm.global_ctors", M, New);
294 SplitStaticCtorDtor("llvm.global_dtors", M, New);
299 //===----------------------------------------------------------------------===//
300 // Basic Block Extraction Code
301 //===----------------------------------------------------------------------===//
303 /// ExtractMappedBlocksFromModule - Extract all but the specified basic blocks
304 /// into their own functions. The only detail is that M is actually a module
305 /// cloned from the one the BBs are in, so some mapping needs to be performed.
306 /// If this operation fails for some reason (ie the implementation is buggy),
307 /// this function should return null, otherwise it returns a new Module.
308 Module *BugDriver::ExtractMappedBlocksFromModule(const
309 std::vector<BasicBlock*> &BBs,
311 char *ExtraArg = NULL;
313 sys::Path uniqueFilename("bugpoint-extractblocks");
315 if (uniqueFilename.createTemporaryFileOnDisk(true, &ErrMsg)) {
316 std::cout << "*** Basic Block extraction failed!\n";
317 std::cerr << "Error creating temporary file: " << ErrMsg << "\n";
318 M = swapProgramIn(M);
319 EmitProgressBitcode("basicblockextractfail", true);
323 sys::RemoveFileOnSignal(uniqueFilename);
325 std::ofstream BlocksToNotExtractFile(uniqueFilename.c_str());
326 if (!BlocksToNotExtractFile) {
327 std::cout << "*** Basic Block extraction failed!\n";
328 std::cerr << "Error writing list of blocks to not extract: " << ErrMsg
330 M = swapProgramIn(M);
331 EmitProgressBitcode("basicblockextractfail", true);
335 for (std::vector<BasicBlock*>::const_iterator I = BBs.begin(), E = BBs.end();
338 BlocksToNotExtractFile << BB->getParent()->getName() << " "
339 << BB->getName() << "\n";
341 BlocksToNotExtractFile.close();
343 const char *uniqueFN = uniqueFilename.c_str();
344 ExtraArg = (char*)malloc(23 + strlen(uniqueFN));
345 strcat(strcpy(ExtraArg, "--extract-blocks-file="), uniqueFN);
347 std::vector<const PassInfo*> PI;
348 std::vector<BasicBlock *> EmptyBBs; // This parameter is ignored.
349 PI.push_back(getPI(createBlockExtractorPass(EmptyBBs)));
350 Module *Ret = runPassesOn(M, PI, false, 1, &ExtraArg);
352 if (uniqueFilename.exists())
353 uniqueFilename.eraseFromDisk(); // Free disk space
357 std::cout << "*** Basic Block extraction failed, please report a bug!\n";
358 M = swapProgramIn(M);
359 EmitProgressBitcode("basicblockextractfail", true);