1 //===- ExtractFunction.cpp - Extract a function from Program --------------===// 2 // 3 // This file implements a method that extracts a function from program, cleans 4 // it up, and returns it as a new module. 5 // 6 //===----------------------------------------------------------------------===// 7 8 #include "BugDriver.h" 9 #include "llvm/Module.h" 10 #include "llvm/PassManager.h" 11 #include "llvm/Transforms/IPO.h" 12 #include "llvm/Transforms/Scalar.h" 13 #include "llvm/Transforms/Utils/Cloning.h" 14 #include "llvm/Analysis/Verifier.h" 15 #include "llvm/Type.h" 16 #include "llvm/Constant.h" 17 #include "Support/CommandLine.h" 18 19 namespace { 20 cl::opt<bool> 21 NoADCE("disable-adce", 22 cl::desc("Do not use the -adce pass to reduce testcases")); 23 cl::opt<bool> 24 NoDCE ("disable-dce", 25 cl::desc("Do not use the -dce pass to reduce testcases")); 26 cl::opt<bool> 27 NoSCFG("disable-simplifycfg", 28 cl::desc("Do not use the -simplifycfg pass to reduce testcases")); 29 cl::opt<bool> 30 NoFinalCleanup("disable-final-cleanup", 31 cl::desc("Disable the final cleanup phase of narrowing")); 32 } 33 34 /// deleteInstructionFromProgram - This method clones the current Program and 35 /// deletes the specified instruction from the cloned module. It then runs a 36 /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which 37 /// depends on the value. The modified module is then returned. 38 /// 39 Module *BugDriver::deleteInstructionFromProgram(Instruction *I, 40 unsigned Simplification) const { 41 Module *Result = CloneModule(Program); 42 43 BasicBlock *PBB = I->getParent(); 44 Function *PF = PBB->getParent(); 45 46 Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn 47 std::advance(RFI, std::distance(Program->begin(), Module::iterator(PF))); 48 49 Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB 50 std::advance(RBI, std::distance(PF->begin(), Function::iterator(PBB))); 51 52 BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst 53 std::advance(RI, std::distance(PBB->begin(), BasicBlock::iterator(I))); 54 I = RI; // Got the corresponding instruction! 55 56 // If this instruction produces a value, replace any users with null values 57 if (I->getType() != Type::VoidTy) 58 I->replaceAllUsesWith(Constant::getNullValue(I->getType())); 59 60 // Remove the instruction from the program. 61 I->getParent()->getInstList().erase(I); 62 63 // Spiff up the output a little bit. 64 PassManager Passes; 65 if (Simplification > 2 && !NoADCE) 66 Passes.add(createAggressiveDCEPass()); // Remove dead code... 67 //Passes.add(createInstructionCombiningPass()); 68 if (Simplification > 1 && !NoDCE) 69 Passes.add(createDeadCodeEliminationPass()); 70 if (Simplification && !NoSCFG) 71 Passes.add(createCFGSimplificationPass()); // Delete dead control flow 72 73 Passes.add(createVerifierPass()); 74 Passes.run(*Result); 75 return Result; 76 } 77 78 /// performFinalCleanups - This method clones the current Program and performs 79 /// a series of cleanups intended to get rid of extra cruft on the module 80 /// before handing it to the user... 81 /// 82 Module *BugDriver::performFinalCleanups() const { 83 Module *M = CloneModule(Program); 84 85 // Allow disabling these passes if they crash bugpoint. 86 // 87 // FIXME: This should eventually run these passes in a pass list to prevent 88 // them from being able to crash bugpoint at all! 89 // 90 if (NoFinalCleanup) return M; 91 92 // Make all functions external, so GlobalDCE doesn't delete them... 93 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) 94 I->setLinkage(GlobalValue::ExternalLinkage); 95 96 PassManager CleanupPasses; 97 CleanupPasses.add(createFunctionResolvingPass()); 98 CleanupPasses.add(createGlobalDCEPass()); 99 CleanupPasses.add(createDeadTypeEliminationPass()); 100 CleanupPasses.add(createDeadArgEliminationPass(true)); 101 CleanupPasses.add(createVerifierPass()); 102 CleanupPasses.run(*M); 103 return M; 104 } 105