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 a method that extracts a function from program, cleans
11 // it up, and returns it as a new 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/Target/TargetData.h"
26 #include "Support/CommandLine.h"
31 bool DisableSimplifyCFG = false;
33 } // End llvm namespace
39 NoADCE("disable-adce",
40 cl::desc("Do not use the -adce pass to reduce testcases"));
43 cl::desc("Do not use the -dce pass to reduce testcases"));
45 NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
46 cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
51 /// deleteInstructionFromProgram - This method clones the current Program and
52 /// deletes the specified instruction from the cloned module. It then runs a
53 /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
54 /// depends on the value. The modified module is then returned.
56 Module *BugDriver::deleteInstructionFromProgram(Instruction *I,
57 unsigned Simplification) const {
58 Module *Result = CloneModule(Program);
60 BasicBlock *PBB = I->getParent();
61 Function *PF = PBB->getParent();
63 Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
64 std::advance(RFI, std::distance(Program->begin(), Module::iterator(PF)));
66 Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
67 std::advance(RBI, std::distance(PF->begin(), Function::iterator(PBB)));
69 BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
70 std::advance(RI, std::distance(PBB->begin(), BasicBlock::iterator(I)));
71 I = RI; // Got the corresponding instruction!
73 // If this instruction produces a value, replace any users with null values
74 if (I->getType() != Type::VoidTy)
75 I->replaceAllUsesWith(Constant::getNullValue(I->getType()));
77 // Remove the instruction from the program.
78 I->getParent()->getInstList().erase(I);
80 // Spiff up the output a little bit.
82 // Make sure that the appropriate target data is always used...
83 Passes.add(new TargetData("bugpoint", Result));
85 if (Simplification > 2 && !NoADCE)
86 Passes.add(createAggressiveDCEPass()); // Remove dead code...
87 //Passes.add(createInstructionCombiningPass());
88 if (Simplification > 1 && !NoDCE)
89 Passes.add(createDeadCodeEliminationPass());
90 if (Simplification && !DisableSimplifyCFG)
91 Passes.add(createCFGSimplificationPass()); // Delete dead control flow
93 Passes.add(createVerifierPass());
98 static const PassInfo *getPI(Pass *P) {
99 const PassInfo *PI = P->getPassInfo();
104 /// performFinalCleanups - This method clones the current Program and performs
105 /// a series of cleanups intended to get rid of extra cruft on the module
106 /// before handing it to the user...
108 Module *BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
109 // Make all functions external, so GlobalDCE doesn't delete them...
110 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
111 I->setLinkage(GlobalValue::ExternalLinkage);
113 std::vector<const PassInfo*> CleanupPasses;
114 CleanupPasses.push_back(getPI(createFunctionResolvingPass()));
115 CleanupPasses.push_back(getPI(createGlobalDCEPass()));
116 CleanupPasses.push_back(getPI(createDeadTypeEliminationPass()));
117 CleanupPasses.push_back(getPI(createDeadArgHackingPass()));
119 std::swap(Program, M);
120 std::string Filename;
121 bool Failed = runPasses(CleanupPasses, Filename);
122 std::swap(Program, M);
125 std::cerr << "Final cleanups failed. Sorry. :(\n";
128 M = ParseInputFile(Filename);
130 std::cerr << getToolName() << ": Error reading bytecode file '"
131 << Filename << "'!\n";
138 } // End llvm namespace