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llvm-mirror/tools/bugpoint/ExtractFunction.cpp
Chandler Carruth ee051af6e2 [cleanup] Move the Dominators.h and Verifier.h headers into the IR 
directory. These passes are already defined in the IR library, and it
doesn't make any sense to have the headers in Analysis.

Long term, I think there is going to be a much better way to divide
these matters. The dominators code should be fully separated into the
abstract graph algorithm and have that put in Support where it becomes
obvious that evn Clang's CFGBlock's can use it. Then the verifier can
manually construct dominance information from the Support-driven
interface while the Analysis library can provide a pass which both
caches, reconstructs, and supports a nice update API.

But those are very long term, and so I don't want to leave the really
confusing structure until that day arrives.

llvm-svn: 199082
2014-01-13 09:26:24 +00:00

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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;
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 0;
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 0;
}
} // end anonymous namespace
/// deleteInstructionFromProgram - This method clones the current Program and
/// deletes the specified instruction from the cloned module. It then runs a
/// series of cleanup passes (ADCE and SimplifyCFG) to eliminate any code which
/// depends on the value. The modified module is then returned.
///
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");
Module *New = runPassesOn(Clone, Passes);
delete Clone;
if (!New) {
errs() << "Instruction removal failed. Sorry. :( Please report a bug!\n";
exit(1);
}
return New;
}
/// performFinalCleanups - This method clones the current Program and performs
/// a series of cleanups intended to get rid of extra cruft on the module
/// before handing it to the user.
///
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");
Module *New = runPassesOn(M, CleanupPasses);
if (New == 0) {
errs() << "Final cleanups failed. Sorry. :( Please report a bug!\n";
return M;
}
delete M;
return New;
}
/// ExtractLoop - Given a module, extract up to one loop from it into a new
/// function. This returns null if there are no extractable loops in the
/// program or if the loop extractor crashes.
Module *BugDriver::ExtractLoop(Module *M) {
std::vector<std::string> LoopExtractPasses;
LoopExtractPasses.push_back("loop-extract-single");
Module *NewM = runPassesOn(M, LoopExtractPasses);
if (NewM == 0) {
outs() << "*** Loop extraction failed: ";
EmitProgressBitcode(M, "loopextraction", true);
outs() << "*** Sorry. :( Please report a bug!\n";
return 0;
}
// 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) {
delete NewM;
return 0;
} 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(0); // 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(0);
}
}
// 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
//===----------------------------------------------------------------------===//
/// ExtractMappedBlocksFromModule - Extract all but the specified basic blocks
/// into their own functions. The only detail is that M is actually a module
/// cloned from the one the BBs are in, so some mapping needs to be performed.
/// If this operation fails for some reason (ie the implementation is buggy),
/// this function should return null, otherwise it returns a new Module.
Module *BugDriver::ExtractMappedBlocksFromModule(const
std::vector<BasicBlock*> &BBs,
Module *M) {
SmallString<128> Filename;
int FD;
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 0;
}
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 0;
}
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");
Module *Ret = runPassesOn(M, PI, false, 1, &ExtraArg);
sys::fs::remove(Filename.c_str());
if (Ret == 0) {
outs() << "*** Basic Block extraction failed, please report a bug!\n";
EmitProgressBitcode(M, "basicblockextractfail", true);
}
return Ret;
}
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