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llvm-mirror/tools/bugpoint/ExtractFunction.cpp
Rafael Espindola 7c0442fa71 Return a std::unique_ptr from parseInputFile and propagate. NFC. 
The memory management in BugPoint is fairly convoluted, so this just unwraps
one layer by changing the return type of functions that always return
owned Modules.

llvm-svn: 216464
2014-08-26 17:19:03 +00:00

397 lines
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//===- ExtractFunction.cpp - Extract a function from Program --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements several methods that are used to extract functions,
// loops, or portions of a module from the rest of the module.
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Pass.h"
#include "llvm/PassManager.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/CodeExtractor.h"
#include <set>
using namespace llvm;
#define DEBUG_TYPE "bugpoint"
namespace llvm {
bool DisableSimplifyCFG = false;
extern cl::opt<std::string> OutputPrefix;
} // End llvm namespace
namespace {
cl::opt<bool>
NoDCE ("disable-dce",
cl::desc("Do not use the -dce pass to reduce testcases"));
cl::opt<bool, true>
NoSCFG("disable-simplifycfg", cl::location(DisableSimplifyCFG),
cl::desc("Do not use the -simplifycfg pass to reduce testcases"));
Function* globalInitUsesExternalBA(GlobalVariable* GV) {
if (!GV->hasInitializer())
return nullptr;
Constant *I = GV->getInitializer();
// walk the values used by the initializer
// (and recurse into things like ConstantExpr)
std::vector<Constant*> Todo;
std::set<Constant*> Done;
Todo.push_back(I);
while (!Todo.empty()) {
Constant* V = Todo.back();
Todo.pop_back();
Done.insert(V);
if (BlockAddress *BA = dyn_cast<BlockAddress>(V)) {
Function *F = BA->getFunction();
if (F->isDeclaration())
return F;
}
for (User::op_iterator i = V->op_begin(), e = V->op_end(); i != e; ++i) {
Constant *C = dyn_cast<Constant>(*i);
if (C && !isa<GlobalValue>(C) && !Done.count(C))
Todo.push_back(C);
}
}
return nullptr;
}
} // end anonymous namespace
std::unique_ptr<Module>
BugDriver::deleteInstructionFromProgram(const Instruction *I,
unsigned Simplification) {
// FIXME, use vmap?
Module *Clone = CloneModule(Program);
const BasicBlock *PBB = I->getParent();
const Function *PF = PBB->getParent();
Module::iterator RFI = Clone->begin(); // Get iterator to corresponding fn
std::advance(RFI, std::distance(PF->getParent()->begin(),
Module::const_iterator(PF)));
Function::iterator RBI = RFI->begin(); // Get iterator to corresponding BB
std::advance(RBI, std::distance(PF->begin(), Function::const_iterator(PBB)));
BasicBlock::iterator RI = RBI->begin(); // Get iterator to corresponding inst
std::advance(RI, std::distance(PBB->begin(), BasicBlock::const_iterator(I)));
Instruction *TheInst = RI; // Got the corresponding instruction!
// If this instruction produces a value, replace any users with null values
if (!TheInst->getType()->isVoidTy())
TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
// Remove the instruction from the program.
TheInst->getParent()->getInstList().erase(TheInst);
// Spiff up the output a little bit.
std::vector<std::string> Passes;
/// Can we get rid of the -disable-* options?
if (Simplification > 1 && !NoDCE)
Passes.push_back("dce");
if (Simplification && !DisableSimplifyCFG)
Passes.push_back("simplifycfg"); // Delete dead control flow
Passes.push_back("verify");
std::unique_ptr<Module> New = runPassesOn(Clone, Passes);
delete Clone;
if (!New) {
errs() << "Instruction removal failed. Sorry. :( Please report a bug!\n";
exit(1);
}
return New;
}
std::unique_ptr<Module>
BugDriver::performFinalCleanups(Module *M, bool MayModifySemantics) {
// Make all functions external, so GlobalDCE doesn't delete them...
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
I->setLinkage(GlobalValue::ExternalLinkage);
std::vector<std::string> CleanupPasses;
CleanupPasses.push_back("globaldce");
if (MayModifySemantics)
CleanupPasses.push_back("deadarghaX0r");
else
CleanupPasses.push_back("deadargelim");
std::unique_ptr<Module> New = runPassesOn(M, CleanupPasses);
if (!New) {
errs() << "Final cleanups failed. Sorry. :( Please report a bug!\n";
return nullptr;
}
delete M;
return New;
}
std::unique_ptr<Module> BugDriver::extractLoop(Module *M) {
std::vector<std::string> LoopExtractPasses;
LoopExtractPasses.push_back("loop-extract-single");
std::unique_ptr<Module> NewM = runPassesOn(M, LoopExtractPasses);
if (!NewM) {
outs() << "*** Loop extraction failed: ";
EmitProgressBitcode(M, "loopextraction", true);
outs() << "*** Sorry. :( Please report a bug!\n";
return nullptr;
}
// Check to see if we created any new functions. If not, no loops were
// extracted and we should return null. Limit the number of loops we extract
// to avoid taking forever.
static unsigned NumExtracted = 32;
if (M->size() == NewM->size() || --NumExtracted == 0) {
return nullptr;
} else {
assert(M->size() < NewM->size() && "Loop extract removed functions?");
Module::iterator MI = NewM->begin();
for (unsigned i = 0, e = M->size(); i != e; ++i)
++MI;
}
return NewM;
}
// DeleteFunctionBody - "Remove" the function by deleting all of its basic
// blocks, making it external.
//
void llvm::DeleteFunctionBody(Function *F) {
// delete the body of the function...
F->deleteBody();
assert(F->isDeclaration() && "This didn't make the function external!");
}
/// GetTorInit - Given a list of entries for static ctors/dtors, return them
/// as a constant array.
static Constant *GetTorInit(std::vector<std::pair<Function*, int> > &TorList) {
assert(!TorList.empty() && "Don't create empty tor list!");
std::vector<Constant*> ArrayElts;
Type *Int32Ty = Type::getInt32Ty(TorList[0].first->getContext());
StructType *STy =
StructType::get(Int32Ty, TorList[0].first->getType(), NULL);
for (unsigned i = 0, e = TorList.size(); i != e; ++i) {
Constant *Elts[] = {
ConstantInt::get(Int32Ty, TorList[i].second),
TorList[i].first
};
ArrayElts.push_back(ConstantStruct::get(STy, Elts));
}
return ConstantArray::get(ArrayType::get(ArrayElts[0]->getType(),
ArrayElts.size()),
ArrayElts);
}
/// SplitStaticCtorDtor - A module was recently split into two parts, M1/M2, and
/// M1 has all of the global variables. If M2 contains any functions that are
/// static ctors/dtors, we need to add an llvm.global_[cd]tors global to M2, and
/// prune appropriate entries out of M1s list.
static void SplitStaticCtorDtor(const char *GlobalName, Module *M1, Module *M2,
ValueToValueMapTy &VMap) {
GlobalVariable *GV = M1->getNamedGlobal(GlobalName);
if (!GV || GV->isDeclaration() || GV->hasLocalLinkage() ||
!GV->use_empty()) return;
std::vector<std::pair<Function*, int> > M1Tors, M2Tors;
ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
if (!InitList) return;
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
if (CS->getOperand(1)->isNullValue())
break; // Found a null terminator, stop here.
ConstantInt *CI = dyn_cast<ConstantInt>(CS->getOperand(0));
int Priority = CI ? CI->getSExtValue() : 0;
Constant *FP = CS->getOperand(1);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(FP))
if (CE->isCast())
FP = CE->getOperand(0);
if (Function *F = dyn_cast<Function>(FP)) {
if (!F->isDeclaration())
M1Tors.push_back(std::make_pair(F, Priority));
else {
// Map to M2's version of the function.
F = cast<Function>(VMap[F]);
M2Tors.push_back(std::make_pair(F, Priority));
}
}
}
}
GV->eraseFromParent();
if (!M1Tors.empty()) {
Constant *M1Init = GetTorInit(M1Tors);
new GlobalVariable(*M1, M1Init->getType(), false,
GlobalValue::AppendingLinkage,
M1Init, GlobalName);
}
GV = M2->getNamedGlobal(GlobalName);
assert(GV && "Not a clone of M1?");
assert(GV->use_empty() && "llvm.ctors shouldn't have uses!");
GV->eraseFromParent();
if (!M2Tors.empty()) {
Constant *M2Init = GetTorInit(M2Tors);
new GlobalVariable(*M2, M2Init->getType(), false,
GlobalValue::AppendingLinkage,
M2Init, GlobalName);
}
}
/// SplitFunctionsOutOfModule - Given a module and a list of functions in the
/// module, split the functions OUT of the specified module, and place them in
/// the new module.
Module *
llvm::SplitFunctionsOutOfModule(Module *M,
const std::vector<Function*> &F,
ValueToValueMapTy &VMap) {
// Make sure functions & globals are all external so that linkage
// between the two modules will work.
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
I->setLinkage(GlobalValue::ExternalLinkage);
for (Module::global_iterator I = M->global_begin(), E = M->global_end();
I != E; ++I) {
if (I->hasName() && I->getName()[0] == '\01')
I->setName(I->getName().substr(1));
I->setLinkage(GlobalValue::ExternalLinkage);
}
ValueToValueMapTy NewVMap;
Module *New = CloneModule(M, NewVMap);
// Remove the Test functions from the Safe module
std::set<Function *> TestFunctions;
for (unsigned i = 0, e = F.size(); i != e; ++i) {
Function *TNOF = cast<Function>(VMap[F[i]]);
DEBUG(errs() << "Removing function ");
DEBUG(TNOF->printAsOperand(errs(), false));
DEBUG(errs() << "\n");
TestFunctions.insert(cast<Function>(NewVMap[TNOF]));
DeleteFunctionBody(TNOF); // Function is now external in this module!
}
// Remove the Safe functions from the Test module
for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I)
if (!TestFunctions.count(I))
DeleteFunctionBody(I);
// Try to split the global initializers evenly
for (Module::global_iterator I = M->global_begin(), E = M->global_end();
I != E; ++I) {
GlobalVariable *GV = cast<GlobalVariable>(NewVMap[I]);
if (Function *TestFn = globalInitUsesExternalBA(I)) {
if (Function *SafeFn = globalInitUsesExternalBA(GV)) {
errs() << "*** Error: when reducing functions, encountered "
"the global '";
GV->printAsOperand(errs(), false);
errs() << "' with an initializer that references blockaddresses "
"from safe function '" << SafeFn->getName()
<< "' and from test function '" << TestFn->getName() << "'.\n";
exit(1);
}
I->setInitializer(nullptr); // Delete the initializer to make it external
} else {
// If we keep it in the safe module, then delete it in the test module
GV->setInitializer(nullptr);
}
}
// Make sure that there is a global ctor/dtor array in both halves of the
// module if they both have static ctor/dtor functions.
SplitStaticCtorDtor("llvm.global_ctors", M, New, NewVMap);
SplitStaticCtorDtor("llvm.global_dtors", M, New, NewVMap);
return New;
}
//===----------------------------------------------------------------------===//
// Basic Block Extraction Code
//===----------------------------------------------------------------------===//
std::unique_ptr<Module>
BugDriver::extractMappedBlocksFromModule(const std::vector<BasicBlock *> &BBs,
Module *M) {
SmallString<128> Filename;
int FD;
std::error_code EC = sys::fs::createUniqueFile(
OutputPrefix + "-extractblocks%%%%%%%", FD, Filename);
if (EC) {
outs() << "*** Basic Block extraction failed!\n";
errs() << "Error creating temporary file: " << EC.message() << "\n";
EmitProgressBitcode(M, "basicblockextractfail", true);
return nullptr;
}
sys::RemoveFileOnSignal(Filename);
tool_output_file BlocksToNotExtractFile(Filename.c_str(), FD);
for (std::vector<BasicBlock*>::const_iterator I = BBs.begin(), E = BBs.end();
I != E; ++I) {
BasicBlock *BB = *I;
// If the BB doesn't have a name, give it one so we have something to key
// off of.
if (!BB->hasName()) BB->setName("tmpbb");
BlocksToNotExtractFile.os() << BB->getParent()->getName() << " "
<< BB->getName() << "\n";
}
BlocksToNotExtractFile.os().close();
if (BlocksToNotExtractFile.os().has_error()) {
errs() << "Error writing list of blocks to not extract\n";
EmitProgressBitcode(M, "basicblockextractfail", true);
BlocksToNotExtractFile.os().clear_error();
return nullptr;
}
BlocksToNotExtractFile.keep();
std::string uniqueFN = "--extract-blocks-file=";
uniqueFN += Filename.str();
const char *ExtraArg = uniqueFN.c_str();
std::vector<std::string> PI;
PI.push_back("extract-blocks");
std::unique_ptr<Module> Ret = runPassesOn(M, PI, false, 1, &ExtraArg);
sys::fs::remove(Filename.c_str());
if (!Ret) {
outs() << "*** Basic Block extraction failed, please report a bug!\n";
EmitProgressBitcode(M, "basicblockextractfail", true);
}
return Ret;
}
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