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 "Support/CommandLine.h"
28 #include "Support/Debug.h"
29 #include "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";
128 /// ExtractLoop - Given a module, extract up to one loop from it into a new
129 /// function. This returns null if there are no extractable loops in the
130 /// program or if the loop extractor crashes.
131 Module *BugDriver::ExtractLoop(Module *M) {
132 std::vector<const PassInfo*> LoopExtractPasses;
133 LoopExtractPasses.push_back(getPI(createSingleLoopExtractorPass()));
135 Module *NewM = runPassesOn(M, LoopExtractPasses);
137 Module *Old = swapProgramIn(M);
138 std::cout << "*** Loop extraction failed: ";
139 EmitProgressBytecode("loopextraction", true);
140 std::cout << "*** Sorry. :( Please report a bug!\n";
145 // Check to see if we created any new functions. If not, no loops were
146 // extracted and we should return null.
147 if (M->size() == NewM->size()) {
156 // DeleteFunctionBody - "Remove" the function by deleting all of its basic
157 // blocks, making it external.
159 void llvm::DeleteFunctionBody(Function *F) {
160 // delete the body of the function...
162 assert(F->isExternal() && "This didn't make the function external!");
165 /// SplitFunctionsOutOfModule - Given a module and a list of functions in the
166 /// module, split the functions OUT of the specified module, and place them in
169 /// FIXME: this could be made DRAMATICALLY more efficient for large programs if
170 /// we just MOVED functions from one module to the other, instead of cloning the
171 /// whole module, then proceeding to delete an entire module's worth of stuff.
173 Module *llvm::SplitFunctionsOutOfModule(Module *M,
174 const std::vector<Function*> &F) {
175 // Make sure functions & globals are all external so that linkage
176 // between the two modules will work.
177 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
178 I->setLinkage(GlobalValue::ExternalLinkage);
179 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
180 I->setLinkage(GlobalValue::ExternalLinkage);
182 Module *New = CloneModule(M);
184 // Make sure global initializers exist only in the safe module (CBE->.so)
185 for (Module::giterator I = New->gbegin(), E = New->gend(); I != E; ++I)
186 I->setInitializer(0); // Delete the initializer to make it external
188 // Remove the Test functions from the Safe module
189 std::set<std::pair<std::string, const PointerType*> > TestFunctions;
190 for (unsigned i = 0, e = F.size(); i != e; ++i) {
191 TestFunctions.insert(std::make_pair(F[i]->getName(), F[i]->getType()));
192 Function *TNOF = M->getFunction(F[i]->getName(), F[i]->getFunctionType());
193 DEBUG(std::cerr << "Removing function " << F[i]->getName() << "\n");
194 assert(TNOF && "Function doesn't exist in module!");
195 DeleteFunctionBody(TNOF); // Function is now external in this module!
198 // Remove the Safe functions from the Test module
199 for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I)
200 if (!TestFunctions.count(std::make_pair(I->getName(), I->getType())))
201 DeleteFunctionBody(I);
205 //===----------------------------------------------------------------------===//
206 // Basic Block Extraction Code
207 //===----------------------------------------------------------------------===//
210 std::vector<BasicBlock*> BlocksToNotExtract;
212 /// BlockExtractorPass - This pass is used by bugpoint to extract all blocks
213 /// from the module into their own functions except for those specified by the
214 /// BlocksToNotExtract list.
215 class BlockExtractorPass : public Pass {
218 RegisterOpt<BlockExtractorPass>
219 XX("extract-bbs", "Extract Basic Blocks From Module (for bugpoint use)");
222 bool BlockExtractorPass::run(Module &M) {
223 std::set<BasicBlock*> TranslatedBlocksToNotExtract;
224 for (unsigned i = 0, e = BlocksToNotExtract.size(); i != e; ++i) {
225 BasicBlock *BB = BlocksToNotExtract[i];
226 Function *F = BB->getParent();
228 // Map the corresponding function in this module.
229 Function *MF = M.getFunction(F->getName(), F->getFunctionType());
231 // Figure out which index the basic block is in its function.
232 Function::iterator BBI = MF->begin();
233 std::advance(BBI, std::distance(F->begin(), Function::iterator(BB)));
234 TranslatedBlocksToNotExtract.insert(BBI);
237 // Now that we know which blocks to not extract, figure out which ones we WANT
239 std::vector<BasicBlock*> BlocksToExtract;
240 for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
241 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
242 if (!TranslatedBlocksToNotExtract.count(BB))
243 BlocksToExtract.push_back(BB);
245 for (unsigned i = 0, e = BlocksToExtract.size(); i != e; ++i)
246 ExtractBasicBlock(BlocksToExtract[i]);
248 return !BlocksToExtract.empty();
251 /// ExtractMappedBlocksFromModule - Extract all but the specified basic blocks
252 /// into their own functions. The only detail is that M is actually a module
253 /// cloned from the one the BBs are in, so some mapping needs to be performed.
254 /// If this operation fails for some reason (ie the implementation is buggy),
255 /// this function should return null, otherwise it returns a new Module.
256 Module *BugDriver::ExtractMappedBlocksFromModule(const
257 std::vector<BasicBlock*> &BBs,
259 // Set the global list so that pass will be able to access it.
260 BlocksToNotExtract = BBs;
262 std::vector<const PassInfo*> PI;
263 PI.push_back(getPI(new BlockExtractorPass()));
264 Module *Ret = runPassesOn(M, PI);
265 BlocksToNotExtract.clear();
267 std::cout << "*** Basic Block extraction failed, please report a bug!\n";