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/Target/TargetData.h"
26 #include "Support/CommandLine.h"
27 #include "Support/Debug.h"
28 #include "Support/FileUtilities.h"
32 bool DisableSimplifyCFG = false;
33 } // End llvm namespace
38 cl::desc("Do not use the -dce pass to reduce testcases"));
40 NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
41 cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
44 /// deleteInstructionFromProgram - This method clones the current Program and
45 /// deletes the specified instruction from the cloned module. It then runs a
46 /// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
47 /// depends on the value. The modified module is then returned.
49 Module *BugDriver::deleteInstructionFromProgram(const Instruction *I,
50 unsigned Simplification) const {
51 Module *Result = CloneModule(Program);
53 const BasicBlock *PBB = I->getParent();
54 const Function *PF = PBB->getParent();
56 Module::iterator RFI = Result->begin(); // Get iterator to corresponding fn
57 std::advance(RFI, std::distance(PF->getParent()->begin(),
58 Module::const_iterator(PF)));
60 Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
61 std::advance(RBI, std::distance(PF->begin(), Function::const_iterator(PBB)));
63 BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
64 std::advance(RI, std::distance(PBB->begin(), BasicBlock::const_iterator(I)));
65 Instruction *TheInst = RI; // Got the corresponding instruction!
67 // If this instruction produces a value, replace any users with null values
68 if (TheInst->getType() != Type::VoidTy)
69 TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
71 // Remove the instruction from the program.
72 TheInst->getParent()->getInstList().erase(TheInst);
74 // Spiff up the output a little bit.
76 // Make sure that the appropriate target data is always used...
77 Passes.add(new TargetData("bugpoint", Result));
79 /// FIXME: If this used runPasses() like the methods below, we could get rid
80 /// of the -disable-* options!
81 if (Simplification > 1 && !NoDCE)
82 Passes.add(createDeadCodeEliminationPass());
83 if (Simplification && !DisableSimplifyCFG)
84 Passes.add(createCFGSimplificationPass()); // Delete dead control flow
86 Passes.add(createVerifierPass());
91 static const PassInfo *getPI(Pass *P) {
92 const PassInfo *PI = P->getPassInfo();
97 /// performFinalCleanups - This method clones the current Program and performs
98 /// a series of cleanups intended to get rid of extra cruft on the module
99 /// before handing it to the user...
101 Module *BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
102 // Make all functions external, so GlobalDCE doesn't delete them...
103 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
104 I->setLinkage(GlobalValue::ExternalLinkage);
106 std::vector<const PassInfo*> CleanupPasses;
107 CleanupPasses.push_back(getPI(createFunctionResolvingPass()));
108 CleanupPasses.push_back(getPI(createGlobalDCEPass()));
109 CleanupPasses.push_back(getPI(createDeadTypeEliminationPass()));
111 if (MayModifySemantics)
112 CleanupPasses.push_back(getPI(createDeadArgHackingPass()));
114 CleanupPasses.push_back(getPI(createDeadArgEliminationPass()));
116 Module *New = runPassesOn(M, CleanupPasses);
118 std::cerr << "Final cleanups failed. Sorry. :( Please report a bug!\n";
125 /// ExtractLoop - Given a module, extract up to one loop from it into a new
126 /// function. This returns null if there are no extractable loops in the
127 /// program or if the loop extractor crashes.
128 Module *BugDriver::ExtractLoop(Module *M) {
129 std::vector<const PassInfo*> LoopExtractPasses;
130 LoopExtractPasses.push_back(getPI(createSingleLoopExtractorPass()));
132 Module *NewM = runPassesOn(M, LoopExtractPasses);
134 Module *Old = swapProgramIn(M);
135 std::cout << "*** Loop extraction failed: ";
136 EmitProgressBytecode("loopextraction", true);
137 std::cout << "*** Sorry. :( Please report a bug!\n";
142 // Check to see if we created any new functions. If not, no loops were
143 // extracted and we should return null.
144 if (M->size() != NewM->size()) {
153 // DeleteFunctionBody - "Remove" the function by deleting all of its basic
154 // blocks, making it external.
156 void llvm::DeleteFunctionBody(Function *F) {
157 // delete the body of the function...
159 assert(F->isExternal() && "This didn't make the function external!");
162 /// SplitFunctionsOutOfModule - Given a module and a list of functions in the
163 /// module, split the functions OUT of the specified module, and place them in
166 /// FIXME: this could be made DRAMATICALLY more efficient for large programs if
167 /// we just MOVED functions from one module to the other, instead of cloning the
168 /// whole module, then proceeding to delete an entire module's worth of stuff.
170 Module *llvm::SplitFunctionsOutOfModule(Module *M,
171 const std::vector<Function*> &F) {
172 // Make sure functions & globals are all external so that linkage
173 // between the two modules will work.
174 for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
175 I->setLinkage(GlobalValue::ExternalLinkage);
176 for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
177 I->setLinkage(GlobalValue::ExternalLinkage);
179 Module *New = CloneModule(M);
181 // Make sure global initializers exist only in the safe module (CBE->.so)
182 for (Module::giterator I = New->gbegin(), E = New->gend(); I != E; ++I)
183 I->setInitializer(0); // Delete the initializer to make it external
185 // Remove the Test functions from the Safe module
186 for (unsigned i = 0, e = F.size(); i != e; ++i) {
187 Function *TNOF = M->getFunction(F[i]->getName(), F[i]->getFunctionType());
188 DEBUG(std::cerr << "Removing function " << F[i]->getName() << "\n");
189 assert(TNOF && "Function doesn't exist in module!");
190 DeleteFunctionBody(TNOF); // Function is now external in this module!
193 // Remove the Safe functions from the Test module
194 for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I) {
195 bool funcFound = false;
196 for (std::vector<Function*>::const_iterator FI = F.begin(), Fe = F.end();
198 if (I->getName() == (*FI)->getName()) funcFound = true;
201 DeleteFunctionBody(I);