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/Constant.h"
17 #include "llvm/Module.h"
18 #include "llvm/PassManager.h"
19 #include "llvm/Pass.h"
20 #include "llvm/Type.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"
35 bool DisableSimplifyCFG = false;
36 } // End llvm namespace
41 cl::desc("Do not use the -dce pass to reduce testcases"));
43 NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
44 cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
47 /// deleteInstructionFromProgram - This method clones the current Program and
48 /// deletes the specified instruction from the cloned module. It then runs a
49 /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
50 /// depends on the value. The modified module is then returned.
52 Module *BugDriver::deleteInstructionFromProgram(const Instruction *I,
53 unsigned Simplification) const {
54 Module *Result = CloneModule(Program);
56 const BasicBlock *PBB = I->getParent();
57 const Function *PF = PBB->getParent();
59 Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
60 std::advance(RFI, std::distance(PF->getParent()->begin(),
61 Module::const_iterator(PF)));
63 Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
64 std::advance(RBI, std::distance(PF->begin(), Function::const_iterator(PBB)));
66 BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
67 std::advance(RI, std::distance(PBB->begin(), BasicBlock::const_iterator(I)));
68 Instruction *TheInst = RI; // Got the corresponding instruction!
70 // If this instruction produces a value, replace any users with null values
71 if (TheInst->getType() != Type::VoidTy)
72 TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
74 // Remove the instruction from the program.
75 TheInst->getParent()->getInstList().erase(TheInst);
77 // Spiff up the output a little bit.
79 // Make sure that the appropriate target data is always used...
80 Passes.add(new TargetData("bugpoint", Result));
82 /// FIXME: If this used runPasses() like the methods below, we could get rid
83 /// of the -disable-* options!
84 if (Simplification > 1 && !NoDCE)
85 Passes.add(createDeadCodeEliminationPass());
86 if (Simplification && !DisableSimplifyCFG)
87 Passes.add(createCFGSimplificationPass()); // Delete dead control flow
89 Passes.add(createVerifierPass());
94 static const PassInfo *getPI(Pass *P) {
95 const PassInfo *PI = P->getPassInfo();
100 /// performFinalCleanups - This method clones the current Program and performs
101 /// a series of cleanups intended to get rid of extra cruft on the module
102 /// before handing it to the user.
104 Module *BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
105 // Make all functions external, so GlobalDCE doesn't delete them...
106 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
107 I->setLinkage(GlobalValue::ExternalLinkage);
109 std::vector<const PassInfo*> CleanupPasses;
110 CleanupPasses.push_back(getPI(createFunctionResolvingPass()));
111 CleanupPasses.push_back(getPI(createGlobalDCEPass()));
112 CleanupPasses.push_back(getPI(createDeadTypeEliminationPass()));
114 if (MayModifySemantics)
115 CleanupPasses.push_back(getPI(createDeadArgHackingPass()));
117 CleanupPasses.push_back(getPI(createDeadArgEliminationPass()));
119 Module *New = runPassesOn(M, CleanupPasses);
121 std::cerr << "Final cleanups failed. Sorry. :( Please report a bug!\n";
129 /// ExtractLoop - Given a module, extract up to one loop from it into a new
130 /// function. This returns null if there are no extractable loops in the
131 /// program or if the loop extractor crashes.
132 Module *BugDriver::ExtractLoop(Module *M) {
133 std::vector<const PassInfo*> LoopExtractPasses;
134 LoopExtractPasses.push_back(getPI(createSingleLoopExtractorPass()));
136 Module *NewM = runPassesOn(M, LoopExtractPasses);
138 Module *Old = swapProgramIn(M);
139 std::cout << "*** Loop extraction failed: ";
140 EmitProgressBytecode("loopextraction", true);
141 std::cout << "*** Sorry. :( Please report a bug!\n";
146 // Check to see if we created any new functions. If not, no loops were
147 // extracted and we should return null. Limit the number of loops we extract
148 // to avoid taking forever.
149 static unsigned NumExtracted = 32;
150 if (M->size() == NewM->size() || --NumExtracted == 0) {
154 assert(M->size() < NewM->size() && "Loop extract removed functions?");
155 Module::iterator MI = NewM->begin();
156 for (unsigned i = 0, e = M->size(); i != e; ++i)
164 // DeleteFunctionBody - "Remove" the function by deleting all of its basic
165 // blocks, making it external.
167 void llvm::DeleteFunctionBody(Function *F) {
168 // delete the body of the function...
170 assert(F->isExternal() && "This didn't make the function external!");
173 /// SplitFunctionsOutOfModule - Given a module and a list of functions in the
174 /// module, split the functions OUT of the specified module, and place them in
177 /// FIXME: this could be made DRAMATICALLY more efficient for large programs if
178 /// we just MOVED functions from one module to the other, instead of cloning the
179 /// whole module, then proceeding to delete an entire module's worth of stuff.
181 Module *llvm::SplitFunctionsOutOfModule(Module *M,
182 const std::vector<Function*> &F) {
183 // Make sure functions & globals are all external so that linkage
184 // between the two modules will work.
185 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
186 I->setLinkage(GlobalValue::ExternalLinkage);
187 for (Module::global_iterator I = M->global_begin(), E = M->global_end(); I != E; ++I)
188 I->setLinkage(GlobalValue::ExternalLinkage);
190 Module *New = CloneModule(M);
192 // Make sure global initializers exist only in the safe module (CBE->.so)
193 for (Module::global_iterator I = New->global_begin(), E = New->global_end(); I != E; ++I)
194 I->setInitializer(0); // Delete the initializer to make it external
196 // Remove the Test functions from the Safe module
197 std::set<std::pair<std::string, const PointerType*> > TestFunctions;
198 for (unsigned i = 0, e = F.size(); i != e; ++i) {
199 TestFunctions.insert(std::make_pair(F[i]->getName(), F[i]->getType()));
200 Function *TNOF = M->getFunction(F[i]->getName(), F[i]->getFunctionType());
201 DEBUG(std::cerr << "Removing function " << F[i]->getName() << "\n");
202 assert(TNOF && "Function doesn't exist in module!");
203 DeleteFunctionBody(TNOF); // Function is now external in this module!
206 // Remove the Safe functions from the Test module
207 for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I)
208 if (!TestFunctions.count(std::make_pair(I->getName(), I->getType())))
209 DeleteFunctionBody(I);
213 //===----------------------------------------------------------------------===//
214 // Basic Block Extraction Code
215 //===----------------------------------------------------------------------===//
218 std::vector<BasicBlock*> BlocksToNotExtract;
220 /// BlockExtractorPass - This pass is used by bugpoint to extract all blocks
221 /// from the module into their own functions except for those specified by the
222 /// BlocksToNotExtract list.
223 class BlockExtractorPass : public ModulePass {
224 bool runOnModule(Module &M);
226 RegisterOpt<BlockExtractorPass>
227 XX("extract-bbs", "Extract Basic Blocks From Module (for bugpoint use)");
230 bool BlockExtractorPass::runOnModule(Module &M) {
231 std::set<BasicBlock*> TranslatedBlocksToNotExtract;
232 for (unsigned i = 0, e = BlocksToNotExtract.size(); i != e; ++i) {
233 BasicBlock *BB = BlocksToNotExtract[i];
234 Function *F = BB->getParent();
236 // Map the corresponding function in this module.
237 Function *MF = M.getFunction(F->getName(), F->getFunctionType());
239 // Figure out which index the basic block is in its function.
240 Function::iterator BBI = MF->begin();
241 std::advance(BBI, std::distance(F->begin(), Function::iterator(BB)));
242 TranslatedBlocksToNotExtract.insert(BBI);
245 // Now that we know which blocks to not extract, figure out which ones we WANT
247 std::vector<BasicBlock*> BlocksToExtract;
248 for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
249 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
250 if (!TranslatedBlocksToNotExtract.count(BB))
251 BlocksToExtract.push_back(BB);
253 for (unsigned i = 0, e = BlocksToExtract.size(); i != e; ++i)
254 ExtractBasicBlock(BlocksToExtract[i]);
256 return !BlocksToExtract.empty();
259 /// ExtractMappedBlocksFromModule - Extract all but the specified basic blocks
260 /// into their own functions. The only detail is that M is actually a module
261 /// cloned from the one the BBs are in, so some mapping needs to be performed.
262 /// If this operation fails for some reason (ie the implementation is buggy),
263 /// this function should return null, otherwise it returns a new Module.
264 Module *BugDriver::ExtractMappedBlocksFromModule(const
265 std::vector<BasicBlock*> &BBs,
267 // Set the global list so that pass will be able to access it.
268 BlocksToNotExtract = BBs;
270 std::vector<const PassInfo*> PI;
271 PI.push_back(getPI(new BlockExtractorPass()));
272 Module *Ret = runPassesOn(M, PI);
273 BlocksToNotExtract.clear();
275 std::cout << "*** Basic Block extraction failed, please report a bug!\n";
276 M = swapProgramIn(M);
277 EmitProgressBytecode("basicblockextractfail", true);
278 M = swapProgramIn(M);