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"
34 bool DisableSimplifyCFG = false;
35 } // End llvm namespace
40 cl::desc("Do not use the -dce pass to reduce testcases"));
42 NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
43 cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
46 /// deleteInstructionFromProgram - This method clones the current Program and
47 /// deletes the specified instruction from the cloned module. It then runs a
48 /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
49 /// depends on the value. The modified module is then returned.
51 Module *BugDriver::deleteInstructionFromProgram(const Instruction *I,
52 unsigned Simplification) const {
53 Module *Result = CloneModule(Program);
55 const BasicBlock *PBB = I->getParent();
56 const Function *PF = PBB->getParent();
58 Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
59 std::advance(RFI, std::distance(PF->getParent()->begin(),
60 Module::const_iterator(PF)));
62 Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
63 std::advance(RBI, std::distance(PF->begin(), Function::const_iterator(PBB)));
65 BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
66 std::advance(RI, std::distance(PBB->begin(), BasicBlock::const_iterator(I)));
67 Instruction *TheInst = RI; // Got the corresponding instruction!
69 // If this instruction produces a value, replace any users with null values
70 if (TheInst->getType() != Type::VoidTy)
71 TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
73 // Remove the instruction from the program.
74 TheInst->getParent()->getInstList().erase(TheInst);
76 // Spiff up the output a little bit.
78 // Make sure that the appropriate target data is always used...
79 Passes.add(new TargetData("bugpoint", Result));
81 /// FIXME: If this used runPasses() like the methods below, we could get rid
82 /// of the -disable-* options!
83 if (Simplification > 1 && !NoDCE)
84 Passes.add(createDeadCodeEliminationPass());
85 if (Simplification && !DisableSimplifyCFG)
86 Passes.add(createCFGSimplificationPass()); // Delete dead control flow
88 Passes.add(createVerifierPass());
93 static const PassInfo *getPI(Pass *P) {
94 const PassInfo *PI = P->getPassInfo();
99 /// performFinalCleanups - This method clones the current Program and performs
100 /// a series of cleanups intended to get rid of extra cruft on the module
101 /// before handing it to the user...
103 Module *BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
104 // Make all functions external, so GlobalDCE doesn't delete them...
105 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
106 I->setLinkage(GlobalValue::ExternalLinkage);
108 std::vector<const PassInfo*> CleanupPasses;
109 CleanupPasses.push_back(getPI(createFunctionResolvingPass()));
110 CleanupPasses.push_back(getPI(createGlobalDCEPass()));
111 CleanupPasses.push_back(getPI(createDeadTypeEliminationPass()));
113 if (MayModifySemantics)
114 CleanupPasses.push_back(getPI(createDeadArgHackingPass()));
116 CleanupPasses.push_back(getPI(createDeadArgEliminationPass()));
118 Module *New = runPassesOn(M, CleanupPasses);
120 std::cerr << "Final cleanups failed. Sorry. :( Please report a bug!\n";
127 /// ExtractLoop - Given a module, extract up to one loop from it into a new
128 /// function. This returns null if there are no extractable loops in the
129 /// program or if the loop extractor crashes.
130 Module *BugDriver::ExtractLoop(Module *M) {
131 std::vector<const PassInfo*> LoopExtractPasses;
132 LoopExtractPasses.push_back(getPI(createSingleLoopExtractorPass()));
134 Module *NewM = runPassesOn(M, LoopExtractPasses);
136 Module *Old = swapProgramIn(M);
137 std::cout << "*** Loop extraction failed: ";
138 EmitProgressBytecode("loopextraction", true);
139 std::cout << "*** Sorry. :( Please report a bug!\n";
144 // Check to see if we created any new functions. If not, no loops were
145 // extracted and we should return null.
146 if (M->size() == NewM->size()) {
155 // DeleteFunctionBody - "Remove" the function by deleting all of its basic
156 // blocks, making it external.
158 void llvm::DeleteFunctionBody(Function *F) {
159 // delete the body of the function...
161 assert(F->isExternal() && "This didn't make the function external!");
164 /// SplitFunctionsOutOfModule - Given a module and a list of functions in the
165 /// module, split the functions OUT of the specified module, and place them in
168 /// FIXME: this could be made DRAMATICALLY more efficient for large programs if
169 /// we just MOVED functions from one module to the other, instead of cloning the
170 /// whole module, then proceeding to delete an entire module's worth of stuff.
172 Module *llvm::SplitFunctionsOutOfModule(Module *M,
173 const std::vector<Function*> &F) {
174 // Make sure functions & globals are all external so that linkage
175 // between the two modules will work.
176 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
177 I->setLinkage(GlobalValue::ExternalLinkage);
178 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
179 I->setLinkage(GlobalValue::ExternalLinkage);
181 Module *New = CloneModule(M);
183 // Make sure global initializers exist only in the safe module (CBE->.so)
184 for (Module::giterator I = New->gbegin(), E = New->gend(); I != E; ++I)
185 I->setInitializer(0); // Delete the initializer to make it external
187 // Remove the Test functions from the Safe module
188 std::set<std::pair<std::string, const PointerType*> > TestFunctions;
189 for (unsigned i = 0, e = F.size(); i != e; ++i) {
190 TestFunctions.insert(std::make_pair(F[i]->getName(), F[i]->getType()));
191 Function *TNOF = M->getFunction(F[i]->getName(), F[i]->getFunctionType());
192 DEBUG(std::cerr << "Removing function " << F[i]->getName() << "\n");
193 assert(TNOF && "Function doesn't exist in module!");
194 DeleteFunctionBody(TNOF); // Function is now external in this module!
197 // Remove the Safe functions from the Test module
198 for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I)
199 if (!TestFunctions.count(std::make_pair(I->getName(), I->getType())))
200 DeleteFunctionBody(I);
204 //===----------------------------------------------------------------------===//
205 // Basic Block Extraction Code
206 //===----------------------------------------------------------------------===//
209 std::vector<BasicBlock*> BlocksToNotExtract;
211 /// BlockExtractorPass - This pass is used by bugpoint to extract all blocks
212 /// from the module into their own functions except for those specified by the
213 /// BlocksToNotExtract list.
214 class BlockExtractorPass : public Pass {
217 RegisterOpt<BlockExtractorPass>
218 XX("extract-bbs", "Extract Basic Blocks From Module (for bugpoint use)");
221 bool BlockExtractorPass::run(Module &M) {
222 std::set<BasicBlock*> TranslatedBlocksToNotExtract;
223 for (unsigned i = 0, e = BlocksToNotExtract.size(); i != e; ++i) {
224 BasicBlock *BB = BlocksToNotExtract[i];
225 Function *F = BB->getParent();
227 // Map the corresponding function in this module.
228 Function *MF = M.getFunction(F->getName(), F->getFunctionType());
230 // Figure out which index the basic block is in its function.
231 Function::iterator BBI = MF->begin();
232 std::advance(BBI, std::distance(F->begin(), Function::iterator(BB)));
233 TranslatedBlocksToNotExtract.insert(BBI);
236 // Now that we know which blocks to not extract, figure out which ones we WANT
238 std::vector<BasicBlock*> BlocksToExtract;
239 for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
240 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
241 if (!TranslatedBlocksToNotExtract.count(BB))
242 BlocksToExtract.push_back(BB);
244 for (unsigned i = 0, e = BlocksToExtract.size(); i != e; ++i)
245 ExtractBasicBlock(BlocksToExtract[i]);
247 return !BlocksToExtract.empty();
250 /// ExtractMappedBlocksFromModule - Extract all but the specified basic blocks
251 /// into their own functions. The only detail is that M is actually a module
252 /// cloned from the one the BBs are in, so some mapping needs to be performed.
253 /// If this operation fails for some reason (ie the implementation is buggy),
254 /// this function should return null, otherwise it returns a new Module.
255 Module *BugDriver::ExtractMappedBlocksFromModule(const
256 std::vector<BasicBlock*> &BBs,
258 // Set the global list so that pass will be able to access it.
259 BlocksToNotExtract = BBs;
261 std::vector<const PassInfo*> PI;
262 PI.push_back(getPI(new BlockExtractorPass()));
263 Module *Ret = runPassesOn(M, PI);
264 BlocksToNotExtract.clear();
266 std::cout << "*** Basic Block extraction failed, please report a bug!\n";
267 M = swapProgramIn(M);
268 EmitProgressBytecode("basicblockextractfail", true);
269 M = swapProgramIn(M);