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llvm-project/llvm/tools/bugpoint/CrashDebugger.cpp

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//===- CrashDebugger.cpp - Debug compilation crashes ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the bugpoint internals that narrow down compilation crashes
//
//===----------------------------------------------------------------------===//
#include "BugDriver.h"
#include "ListReducer.h"
#include "ToolRunner.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ValueSymbolTable.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include <set>
using namespace llvm;
namespace {
cl::opt<bool> KeepMain("keep-main",
cl::desc("Force function reduction to keep main"),
cl::init(false));
cl::opt<bool> NoGlobalRM("disable-global-remove",
cl::desc("Do not remove global variables"),
cl::init(false));
cl::opt<bool> ReplaceFuncsWithNull(
"replace-funcs-with-null",
cl::desc("When stubbing functions, replace all uses will null"),
cl::init(false));
cl::opt<bool> DontReducePassList("disable-pass-list-reduction",
cl::desc("Skip pass list reduction steps"),
cl::init(false));
cl::opt<bool> NoNamedMDRM("disable-namedmd-remove",
cl::desc("Do not remove global named metadata"),
cl::init(false));
cl::opt<bool> NoStripDebugInfo("disable-strip-debuginfo",
cl::desc("Do not strip debug info metadata"),
cl::init(false));
cl::opt<bool> NoStripDebugTypeInfo("disable-strip-debug-types",
cl::desc("Do not strip debug type info metadata"),
cl::init(false));
cl::opt<bool> VerboseErrors("verbose-errors",
cl::desc("Print the output of crashing program"),
cl::init(false));
}
namespace llvm {
class ReducePassList : public ListReducer<std::string> {
BugDriver &BD;
public:
ReducePassList(BugDriver &bd) : BD(bd) {}
// Return true iff running the "removed" passes succeeds, and running the
// "Kept" passes fail when run on the output of the "removed" passes. If we
// return true, we update the current module of bugpoint.
Expected<TestResult> doTest(std::vector<std::string> &Removed,
std::vector<std::string> &Kept) override;
};
}
Expected<ReducePassList::TestResult>
ReducePassList::doTest(std::vector<std::string> &Prefix,
std::vector<std::string> &Suffix) {
std::string PrefixOutput;
std::unique_ptr<Module> OrigProgram;
if (!Prefix.empty()) {
outs() << "Checking to see if these passes crash: "
<< getPassesString(Prefix) << ": ";
if (BD.runPasses(BD.getProgram(), Prefix, PrefixOutput))
return KeepPrefix;
OrigProgram = std::move(BD.Program);
BD.Program = parseInputFile(PrefixOutput, BD.getContext());
if (BD.Program == nullptr) {
errs() << BD.getToolName() << ": Error reading bitcode file '"
<< PrefixOutput << "'!\n";
exit(1);
}
sys::fs::remove(PrefixOutput);
}
outs() << "Checking to see if these passes crash: " << getPassesString(Suffix)
<< ": ";
if (BD.runPasses(BD.getProgram(), Suffix))
return KeepSuffix; // The suffix crashes alone...
// Nothing failed, restore state...
if (OrigProgram)
BD.Program = std::move(OrigProgram);
return NoFailure;
}
using BugTester = bool (*)(const BugDriver &, Module *);
namespace {
/// ReduceCrashingGlobalInitializers - This works by removing global variable
/// initializers and seeing if the program still crashes. If it does, then we
/// keep that program and try again.
class ReduceCrashingGlobalInitializers : public ListReducer<GlobalVariable *> {
BugDriver &BD;
BugTester TestFn;
public:
ReduceCrashingGlobalInitializers(BugDriver &bd, BugTester testFn)
: BD(bd), TestFn(testFn) {}
Expected<TestResult> doTest(std::vector<GlobalVariable *> &Prefix,
std::vector<GlobalVariable *> &Kept) override {
if (!Kept.empty() && TestGlobalVariables(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestGlobalVariables(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestGlobalVariables(std::vector<GlobalVariable *> &GVs);
};
}
bool ReduceCrashingGlobalInitializers::TestGlobalVariables(
std::vector<GlobalVariable *> &GVs) {
// Clone the program to try hacking it apart...
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
// Convert list to set for fast lookup...
std::set<GlobalVariable *> GVSet;
for (unsigned i = 0, e = GVs.size(); i != e; ++i) {
GlobalVariable *CMGV = cast<GlobalVariable>(VMap[GVs[i]]);
assert(CMGV && "Global Variable not in module?!");
GVSet.insert(CMGV);
}
outs() << "Checking for crash with only these global variables: ";
PrintGlobalVariableList(GVs);
outs() << ": ";
// Loop over and delete any global variables which we aren't supposed to be
// playing with...
for (GlobalVariable &I : M->globals())
if (I.hasInitializer() && !GVSet.count(&I)) {
DeleteGlobalInitializer(&I);
I.setLinkage(GlobalValue::ExternalLinkage);
I.setComdat(nullptr);
}
// Try running the hacked up program...
if (TestFn(BD, M.get())) {
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
// Make sure to use global variable pointers that point into the now-current
// module.
GVs.assign(GVSet.begin(), GVSet.end());
return true;
}
return false;
}
namespace {
/// ReduceCrashingFunctions reducer - This works by removing functions and
/// seeing if the program still crashes. If it does, then keep the newer,
/// smaller program.
///
class ReduceCrashingFunctions : public ListReducer<Function *> {
BugDriver &BD;
BugTester TestFn;
public:
ReduceCrashingFunctions(BugDriver &bd, BugTester testFn)
: BD(bd), TestFn(testFn) {}
Expected<TestResult> doTest(std::vector<Function *> &Prefix,
std::vector<Function *> &Kept) override {
if (!Kept.empty() && TestFuncs(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestFuncs(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestFuncs(std::vector<Function *> &Prefix);
};
}
static void RemoveFunctionReferences(Module *M, const char *Name) {
auto *UsedVar = M->getGlobalVariable(Name, true);
if (!UsedVar || !UsedVar->hasInitializer())
return;
if (isa<ConstantAggregateZero>(UsedVar->getInitializer())) {
assert(UsedVar->use_empty());
UsedVar->eraseFromParent();
return;
}
auto *OldUsedVal = cast<ConstantArray>(UsedVar->getInitializer());
std::vector<Constant *> Used;
for (Value *V : OldUsedVal->operand_values()) {
Constant *Op = cast<Constant>(V->stripPointerCasts());
if (!Op->isNullValue()) {
Used.push_back(cast<Constant>(V));
}
}
auto *NewValElemTy = OldUsedVal->getType()->getElementType();
auto *NewValTy = ArrayType::get(NewValElemTy, Used.size());
auto *NewUsedVal = ConstantArray::get(NewValTy, Used);
UsedVar->mutateType(NewUsedVal->getType()->getPointerTo());
UsedVar->setInitializer(NewUsedVal);
}
bool ReduceCrashingFunctions::TestFuncs(std::vector<Function *> &Funcs) {
// If main isn't present, claim there is no problem.
if (KeepMain && !is_contained(Funcs, BD.getProgram().getFunction("main")))
return false;
// Clone the program to try hacking it apart...
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
// Convert list to set for fast lookup...
std::set<Function *> Functions;
for (unsigned i = 0, e = Funcs.size(); i != e; ++i) {
Function *CMF = cast<Function>(VMap[Funcs[i]]);
assert(CMF && "Function not in module?!");
assert(CMF->getFunctionType() == Funcs[i]->getFunctionType() && "wrong ty");
assert(CMF->getName() == Funcs[i]->getName() && "wrong name");
Functions.insert(CMF);
}
outs() << "Checking for crash with only these functions: ";
PrintFunctionList(Funcs);
outs() << ": ";
if (!ReplaceFuncsWithNull) {
// Loop over and delete any functions which we aren't supposed to be playing
// with...
for (Function &I : *M)
if (!I.isDeclaration() && !Functions.count(&I))
DeleteFunctionBody(&I);
} else {
std::vector<GlobalValue *> ToRemove;
// First, remove aliases to functions we're about to purge.
for (GlobalAlias &Alias : M->aliases()) {
GlobalObject *Root = Alias.getBaseObject();
Function *F = dyn_cast_or_null<Function>(Root);
if (F) {
if (Functions.count(F))
// We're keeping this function.
continue;
} else if (Root->isNullValue()) {
// This referenced a globalalias that we've already replaced,
// so we still need to replace this alias.
} else if (!F) {
// Not a function, therefore not something we mess with.
continue;
}
PointerType *Ty = cast<PointerType>(Alias.getType());
Constant *Replacement = ConstantPointerNull::get(Ty);
Alias.replaceAllUsesWith(Replacement);
ToRemove.push_back(&Alias);
}
for (Function &I : *M) {
if (!I.isDeclaration() && !Functions.count(&I)) {
PointerType *Ty = cast<PointerType>(I.getType());
Constant *Replacement = ConstantPointerNull::get(Ty);
I.replaceAllUsesWith(Replacement);
ToRemove.push_back(&I);
}
}
for (auto *F : ToRemove) {
F->eraseFromParent();
}
// Finally, remove any null members from any global intrinsic.
RemoveFunctionReferences(M.get(), "llvm.used");
RemoveFunctionReferences(M.get(), "llvm.compiler.used");
}
// Try running the hacked up program...
if (TestFn(BD, M.get())) {
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
// Make sure to use function pointers that point into the now-current
// module.
Funcs.assign(Functions.begin(), Functions.end());
return true;
}
return false;
}
namespace {
/// Simplify the CFG without completely destroying it.
/// This is not well defined, but basically comes down to "try to eliminate
/// unreachable blocks and constant fold terminators without deciding that
/// certain undefined behavior cuts off the program at the legs".
void simpleSimplifyCfg(Function &F, SmallVectorImpl<BasicBlock *> &BBs) {
if (F.empty())
return;
for (auto *BB : BBs) {
ConstantFoldTerminator(BB);
MergeBlockIntoPredecessor(BB);
}
// Remove unreachable blocks
// removeUnreachableBlocks can't be used here, it will turn various
// undefined behavior into unreachables, but bugpoint was the thing that
// generated the undefined behavior, and we don't want it to kill the entire
// program.
SmallPtrSet<BasicBlock *, 16> Visited;
for (auto *BB : depth_first(&F.getEntryBlock()))
Visited.insert(BB);
SmallVector<BasicBlock *, 16> Unreachable;
for (auto &BB : F)
if (!Visited.count(&BB))
Unreachable.push_back(&BB);
// The dead BB's may be in a dead cycle or otherwise have references to each
// other. Because of this, we have to drop all references first, then delete
// them all at once.
for (auto *BB : Unreachable) {
for (BasicBlock *Successor : successors(&*BB))
if (Visited.count(Successor))
Successor->removePredecessor(&*BB);
BB->dropAllReferences();
}
for (auto *BB : Unreachable)
BB->eraseFromParent();
}
/// ReduceCrashingBlocks reducer - This works by setting the terminators of
/// all terminators except the specified basic blocks to a 'ret' instruction,
/// then running the simplify-cfg pass. This has the effect of chopping up
/// the CFG really fast which can reduce large functions quickly.
///
class ReduceCrashingBlocks : public ListReducer<const BasicBlock *> {
BugDriver &BD;
BugTester TestFn;
public:
ReduceCrashingBlocks(BugDriver &BD, BugTester testFn)
: BD(BD), TestFn(testFn) {}
Expected<TestResult> doTest(std::vector<const BasicBlock *> &Prefix,
std::vector<const BasicBlock *> &Kept) override {
if (!Kept.empty() && TestBlocks(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestBlocks(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestBlocks(std::vector<const BasicBlock *> &Prefix);
};
}
bool ReduceCrashingBlocks::TestBlocks(std::vector<const BasicBlock *> &BBs) {
// Clone the program to try hacking it apart...
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
// Convert list to set for fast lookup...
SmallPtrSet<BasicBlock *, 8> Blocks;
for (unsigned i = 0, e = BBs.size(); i != e; ++i)
Blocks.insert(cast<BasicBlock>(VMap[BBs[i]]));
outs() << "Checking for crash with only these blocks:";
unsigned NumPrint = Blocks.size();
if (NumPrint > 10)
NumPrint = 10;
for (unsigned i = 0, e = NumPrint; i != e; ++i)
outs() << " " << BBs[i]->getName();
if (NumPrint < Blocks.size())
outs() << "... <" << Blocks.size() << " total>";
outs() << ": ";
// Loop over and delete any hack up any blocks that are not listed...
for (Function &F : M->functions()) {
for (BasicBlock &BB : F) {
if (!Blocks.count(&BB) && BB.getTerminator()->getNumSuccessors()) {
// Loop over all of the successors of this block, deleting any PHI nodes
// that might include it.
for (BasicBlock *Succ : successors(&BB))
Succ->removePredecessor(&BB);
TerminatorInst *BBTerm = BB.getTerminator();
if (BBTerm->isEHPad() || BBTerm->getType()->isTokenTy())
continue;
if (!BBTerm->getType()->isVoidTy())
BBTerm->replaceAllUsesWith(Constant::getNullValue(BBTerm->getType()));
// Replace the old terminator instruction.
BB.getInstList().pop_back();
new UnreachableInst(BB.getContext(), &BB);
}
}
}
// The CFG Simplifier pass may delete one of the basic blocks we are
// interested in. If it does we need to take the block out of the list. Make
// a "persistent mapping" by turning basic blocks into <function, name> pairs.
// This won't work well if blocks are unnamed, but that is just the risk we
// have to take. FIXME: Can we just name the blocks?
std::vector<std::pair<std::string, std::string>> BlockInfo;
for (BasicBlock *BB : Blocks)
BlockInfo.emplace_back(BB->getParent()->getName(), BB->getName());
SmallVector<BasicBlock *, 16> ToProcess;
for (auto &F : *M) {
for (auto &BB : F)
if (!Blocks.count(&BB))
ToProcess.push_back(&BB);
simpleSimplifyCfg(F, ToProcess);
ToProcess.clear();
}
// Verify we didn't break anything
std::vector<std::string> Passes;
Passes.push_back("verify");
std::unique_ptr<Module> New = BD.runPassesOn(M.get(), Passes);
if (!New) {
errs() << "verify failed!\n";
exit(1);
}
M = std::move(New);
// Try running on the hacked up program...
if (TestFn(BD, M.get())) {
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
// Make sure to use basic block pointers that point into the now-current
// module, and that they don't include any deleted blocks.
BBs.clear();
const ValueSymbolTable &GST = BD.getProgram().getValueSymbolTable();
for (const auto &BI : BlockInfo) {
Function *F = cast<Function>(GST.lookup(BI.first));
Value *V = F->getValueSymbolTable()->lookup(BI.second);
if (V && V->getType() == Type::getLabelTy(V->getContext()))
BBs.push_back(cast<BasicBlock>(V));
}
return true;
}
// It didn't crash, try something else.
return false;
}
namespace {
/// ReduceCrashingConditionals reducer - This works by changing
/// conditional branches to unconditional ones, then simplifying the CFG
/// This has the effect of chopping up the CFG really fast which can reduce
/// large functions quickly.
///
class ReduceCrashingConditionals : public ListReducer<const BasicBlock *> {
BugDriver &BD;
BugTester TestFn;
bool Direction;
public:
ReduceCrashingConditionals(BugDriver &bd, BugTester testFn, bool Direction)
: BD(bd), TestFn(testFn), Direction(Direction) {}
Expected<TestResult> doTest(std::vector<const BasicBlock *> &Prefix,
std::vector<const BasicBlock *> &Kept) override {
if (!Kept.empty() && TestBlocks(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestBlocks(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestBlocks(std::vector<const BasicBlock *> &Prefix);
};
}
bool ReduceCrashingConditionals::TestBlocks(
std::vector<const BasicBlock *> &BBs) {
// Clone the program to try hacking it apart...
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
// Convert list to set for fast lookup...
SmallPtrSet<const BasicBlock *, 8> Blocks;
for (const auto *BB : BBs)
Blocks.insert(cast<BasicBlock>(VMap[BB]));
outs() << "Checking for crash with changing conditionals to always jump to "
<< (Direction ? "true" : "false") << ":";
unsigned NumPrint = Blocks.size();
if (NumPrint > 10)
NumPrint = 10;
for (unsigned i = 0, e = NumPrint; i != e; ++i)
outs() << " " << BBs[i]->getName();
if (NumPrint < Blocks.size())
outs() << "... <" << Blocks.size() << " total>";
outs() << ": ";
// Loop over and delete any hack up any blocks that are not listed...
for (auto &F : *M)
for (auto &BB : F)
if (!Blocks.count(&BB)) {
auto *BR = dyn_cast<BranchInst>(BB.getTerminator());
if (!BR || !BR->isConditional())
continue;
if (Direction)
BR->setCondition(ConstantInt::getTrue(BR->getContext()));
else
BR->setCondition(ConstantInt::getFalse(BR->getContext()));
}
// The following may destroy some blocks, so we save them first
std::vector<std::pair<std::string, std::string>> BlockInfo;
for (const BasicBlock *BB : Blocks)
BlockInfo.emplace_back(BB->getParent()->getName(), BB->getName());
SmallVector<BasicBlock *, 16> ToProcess;
for (auto &F : *M) {
for (auto &BB : F)
if (!Blocks.count(&BB))
ToProcess.push_back(&BB);
simpleSimplifyCfg(F, ToProcess);
ToProcess.clear();
}
// Verify we didn't break anything
std::vector<std::string> Passes;
Passes.push_back("verify");
std::unique_ptr<Module> New = BD.runPassesOn(M.get(), Passes);
if (!New) {
errs() << "verify failed!\n";
exit(1);
}
M = std::move(New);
// Try running on the hacked up program...
if (TestFn(BD, M.get())) {
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
// Make sure to use basic block pointers that point into the now-current
// module, and that they don't include any deleted blocks.
BBs.clear();
const ValueSymbolTable &GST = BD.getProgram().getValueSymbolTable();
for (auto &BI : BlockInfo) {
auto *F = cast<Function>(GST.lookup(BI.first));
Value *V = F->getValueSymbolTable()->lookup(BI.second);
if (V && V->getType() == Type::getLabelTy(V->getContext()))
BBs.push_back(cast<BasicBlock>(V));
}
return true;
}
// It didn't crash, try something else.
return false;
}
namespace {
/// SimplifyCFG reducer - This works by calling SimplifyCFG on each basic block
/// in the program.
class ReduceSimplifyCFG : public ListReducer<const BasicBlock *> {
BugDriver &BD;
BugTester TestFn;
TargetTransformInfo TTI;
public:
ReduceSimplifyCFG(BugDriver &bd, BugTester testFn)
: BD(bd), TestFn(testFn), TTI(bd.getProgram().getDataLayout()) {}
Expected<TestResult> doTest(std::vector<const BasicBlock *> &Prefix,
std::vector<const BasicBlock *> &Kept) override {
if (!Kept.empty() && TestBlocks(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestBlocks(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestBlocks(std::vector<const BasicBlock *> &Prefix);
};
}
bool ReduceSimplifyCFG::TestBlocks(std::vector<const BasicBlock *> &BBs) {
// Clone the program to try hacking it apart...
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
// Convert list to set for fast lookup...
SmallPtrSet<const BasicBlock *, 8> Blocks;
for (const auto *BB : BBs)
Blocks.insert(cast<BasicBlock>(VMap[BB]));
outs() << "Checking for crash with CFG simplifying:";
unsigned NumPrint = Blocks.size();
if (NumPrint > 10)
NumPrint = 10;
for (unsigned i = 0, e = NumPrint; i != e; ++i)
outs() << " " << BBs[i]->getName();
if (NumPrint < Blocks.size())
outs() << "... <" << Blocks.size() << " total>";
outs() << ": ";
// The following may destroy some blocks, so we save them first
std::vector<std::pair<std::string, std::string>> BlockInfo;
for (const BasicBlock *BB : Blocks)
BlockInfo.emplace_back(BB->getParent()->getName(), BB->getName());
// Loop over and delete any hack up any blocks that are not listed...
for (auto &F : *M)
// Loop over all of the basic blocks and remove them if they are unneeded.
for (Function::iterator BBIt = F.begin(); BBIt != F.end();) {
if (!Blocks.count(&*BBIt)) {
++BBIt;
continue;
}
simplifyCFG(&*BBIt++, TTI);
}
// Verify we didn't break anything
std::vector<std::string> Passes;
Passes.push_back("verify");
std::unique_ptr<Module> New = BD.runPassesOn(M.get(), Passes);
if (!New) {
errs() << "verify failed!\n";
exit(1);
}
M = std::move(New);
// Try running on the hacked up program...
if (TestFn(BD, M.get())) {
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
// Make sure to use basic block pointers that point into the now-current
// module, and that they don't include any deleted blocks.
BBs.clear();
const ValueSymbolTable &GST = BD.getProgram().getValueSymbolTable();
for (auto &BI : BlockInfo) {
auto *F = cast<Function>(GST.lookup(BI.first));
Value *V = F->getValueSymbolTable()->lookup(BI.second);
if (V && V->getType() == Type::getLabelTy(V->getContext()))
BBs.push_back(cast<BasicBlock>(V));
}
return true;
}
// It didn't crash, try something else.
return false;
}
namespace {
/// ReduceCrashingInstructions reducer - This works by removing the specified
/// non-terminator instructions and replacing them with undef.
///
class ReduceCrashingInstructions : public ListReducer<const Instruction *> {
BugDriver &BD;
BugTester TestFn;
public:
ReduceCrashingInstructions(BugDriver &bd, BugTester testFn)
: BD(bd), TestFn(testFn) {}
Expected<TestResult> doTest(std::vector<const Instruction *> &Prefix,
std::vector<const Instruction *> &Kept) override {
if (!Kept.empty() && TestInsts(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestInsts(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestInsts(std::vector<const Instruction *> &Prefix);
};
}
bool ReduceCrashingInstructions::TestInsts(
std::vector<const Instruction *> &Insts) {
// Clone the program to try hacking it apart...
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
// Convert list to set for fast lookup...
SmallPtrSet<Instruction *, 32> Instructions;
for (unsigned i = 0, e = Insts.size(); i != e; ++i) {
assert(!Insts[i]->isTerminator());
Instructions.insert(cast<Instruction>(VMap[Insts[i]]));
}
outs() << "Checking for crash with only " << Instructions.size();
if (Instructions.size() == 1)
outs() << " instruction: ";
else
outs() << " instructions: ";
for (Module::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI)
for (Function::iterator FI = MI->begin(), FE = MI->end(); FI != FE; ++FI)
for (BasicBlock::iterator I = FI->begin(), E = FI->end(); I != E;) {
Instruction *Inst = &*I++;
if (!Instructions.count(Inst) && !Inst->isTerminator() &&
!Inst->isEHPad() && !Inst->getType()->isTokenTy() &&
!Inst->isSwiftError()) {
if (!Inst->getType()->isVoidTy())
Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
Inst->eraseFromParent();
}
}
// Verify that this is still valid.
legacy::PassManager Passes;
Passes.add(createVerifierPass(/*FatalErrors=*/false));
Passes.run(*M);
// Try running on the hacked up program...
if (TestFn(BD, M.get())) {
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
// Make sure to use instruction pointers that point into the now-current
// module, and that they don't include any deleted blocks.
Insts.clear();
for (Instruction *Inst : Instructions)
Insts.push_back(Inst);
return true;
}
// It didn't crash, try something else.
return false;
}
namespace {
// Reduce the list of Named Metadata nodes. We keep this as a list of
// names to avoid having to convert back and forth every time.
class ReduceCrashingNamedMD : public ListReducer<std::string> {
BugDriver &BD;
BugTester TestFn;
public:
ReduceCrashingNamedMD(BugDriver &bd, BugTester testFn)
: BD(bd), TestFn(testFn) {}
Expected<TestResult> doTest(std::vector<std::string> &Prefix,
std::vector<std::string> &Kept) override {
if (!Kept.empty() && TestNamedMDs(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestNamedMDs(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestNamedMDs(std::vector<std::string> &NamedMDs);
};
}
bool ReduceCrashingNamedMD::TestNamedMDs(std::vector<std::string> &NamedMDs) {
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
outs() << "Checking for crash with only these named metadata nodes:";
unsigned NumPrint = std::min<size_t>(NamedMDs.size(), 10);
for (unsigned i = 0, e = NumPrint; i != e; ++i)
outs() << " " << NamedMDs[i];
if (NumPrint < NamedMDs.size())
outs() << "... <" << NamedMDs.size() << " total>";
outs() << ": ";
// Make a StringMap for faster lookup
StringSet<> Names;
for (const std::string &Name : NamedMDs)
Names.insert(Name);
// First collect all the metadata to delete in a vector, then
// delete them all at once to avoid invalidating the iterator
std::vector<NamedMDNode *> ToDelete;
ToDelete.reserve(M->named_metadata_size() - Names.size());
for (auto &NamedMD : M->named_metadata())
// Always keep a nonempty llvm.dbg.cu because the Verifier would complain.
if (!Names.count(NamedMD.getName()) &&
(!(NamedMD.getName() == "llvm.dbg.cu" && NamedMD.getNumOperands() > 0)))
ToDelete.push_back(&NamedMD);
for (auto *NamedMD : ToDelete)
NamedMD->eraseFromParent();
// Verify that this is still valid.
legacy::PassManager Passes;
Passes.add(createVerifierPass(/*FatalErrors=*/false));
Passes.run(*M);
// Try running on the hacked up program...
if (TestFn(BD, M.get())) {
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
return true;
}
return false;
}
namespace {
// Reduce the list of operands to named metadata nodes
class ReduceCrashingNamedMDOps : public ListReducer<const MDNode *> {
BugDriver &BD;
BugTester TestFn;
public:
ReduceCrashingNamedMDOps(BugDriver &bd, BugTester testFn)
: BD(bd), TestFn(testFn) {}
Expected<TestResult> doTest(std::vector<const MDNode *> &Prefix,
std::vector<const MDNode *> &Kept) override {
if (!Kept.empty() && TestNamedMDOps(Kept))
return KeepSuffix;
if (!Prefix.empty() && TestNamedMDOps(Prefix))
return KeepPrefix;
return NoFailure;
}
bool TestNamedMDOps(std::vector<const MDNode *> &NamedMDOps);
};
}
bool ReduceCrashingNamedMDOps::TestNamedMDOps(
std::vector<const MDNode *> &NamedMDOps) {
// Convert list to set for fast lookup...
SmallPtrSet<const MDNode *, 32> OldMDNodeOps;
for (unsigned i = 0, e = NamedMDOps.size(); i != e; ++i) {
OldMDNodeOps.insert(NamedMDOps[i]);
}
outs() << "Checking for crash with only " << OldMDNodeOps.size();
if (OldMDNodeOps.size() == 1)
outs() << " named metadata operand: ";
else
outs() << " named metadata operands: ";
ValueToValueMapTy VMap;
std::unique_ptr<Module> M = CloneModule(BD.getProgram(), VMap);
// This is a little wasteful. In the future it might be good if we could have
// these dropped during cloning.
for (auto &NamedMD : BD.getProgram().named_metadata()) {
// Drop the old one and create a new one
M->eraseNamedMetadata(M->getNamedMetadata(NamedMD.getName()));
NamedMDNode *NewNamedMDNode =
M->getOrInsertNamedMetadata(NamedMD.getName());
for (MDNode *op : NamedMD.operands())
if (OldMDNodeOps.count(op))
NewNamedMDNode->addOperand(cast<MDNode>(MapMetadata(op, VMap)));
}
// Verify that this is still valid.
legacy::PassManager Passes;
Passes.add(createVerifierPass(/*FatalErrors=*/false));
Passes.run(*M);
// Try running on the hacked up program...
if (TestFn(BD, M.get())) {
// Make sure to use instruction pointers that point into the now-current
// module, and that they don't include any deleted blocks.
NamedMDOps.clear();
for (const MDNode *Node : OldMDNodeOps)
NamedMDOps.push_back(cast<MDNode>(*VMap.getMappedMD(Node)));
BD.setNewProgram(std::move(M)); // It crashed, keep the trimmed version...
return true;
}
// It didn't crash, try something else.
return false;
}
/// Attempt to eliminate as many global initializers as possible.
static Error ReduceGlobalInitializers(BugDriver &BD, BugTester TestFn) {
Module &OrigM = BD.getProgram();
if (OrigM.global_empty())
return Error::success();
// Now try to reduce the number of global variable initializers in the
// module to something small.
std::unique_ptr<Module> M = CloneModule(OrigM);
bool DeletedInit = false;
for (GlobalVariable &GV : M->globals()) {
if (GV.hasInitializer()) {
DeleteGlobalInitializer(&GV);
GV.setLinkage(GlobalValue::ExternalLinkage);
GV.setComdat(nullptr);
DeletedInit = true;
}
}
if (!DeletedInit)
return Error::success();
// See if the program still causes a crash...
outs() << "\nChecking to see if we can delete global inits: ";
if (TestFn(BD, M.get())) { // Still crashes?
BD.setNewProgram(std::move(M));
outs() << "\n*** Able to remove all global initializers!\n";
return Error::success();
}
// No longer crashes.
outs() << " - Removing all global inits hides problem!\n";
std::vector<GlobalVariable *> GVs;
for (GlobalVariable &GV : OrigM.globals())
if (GV.hasInitializer())
GVs.push_back(&GV);
if (GVs.size() > 1 && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to reduce the number of global initializers "
<< "in the testcase\n";
unsigned OldSize = GVs.size();
Expected<bool> Result =
ReduceCrashingGlobalInitializers(BD, TestFn).reduceList(GVs);
if (Error E = Result.takeError())
return E;
if (GVs.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-global-variables");
}
return Error::success();
}
static Error ReduceInsts(BugDriver &BD, BugTester TestFn) {
// Attempt to delete instructions using bisection. This should help out nasty
// cases with large basic blocks where the problem is at one end.
if (!BugpointIsInterrupted) {
std::vector<const Instruction *> Insts;
for (const Function &F : BD.getProgram())
for (const BasicBlock &BB : F)
for (const Instruction &I : BB)
if (!I.isTerminator())
Insts.push_back(&I);
Expected<bool> Result =
ReduceCrashingInstructions(BD, TestFn).reduceList(Insts);
if (Error E = Result.takeError())
return E;
}
unsigned Simplification = 2;
do {
if (BugpointIsInterrupted)
// TODO: Should we distinguish this with an "interrupted error"?
return Error::success();
--Simplification;
outs() << "\n*** Attempting to reduce testcase by deleting instruc"
<< "tions: Simplification Level #" << Simplification << '\n';
// Now that we have deleted the functions that are unnecessary for the
// program, try to remove instructions that are not necessary to cause the
// crash. To do this, we loop through all of the instructions in the
// remaining functions, deleting them (replacing any values produced with
// nulls), and then running ADCE and SimplifyCFG. If the transformed input
// still triggers failure, keep deleting until we cannot trigger failure
// anymore.
//
unsigned InstructionsToSkipBeforeDeleting = 0;
TryAgain:
// Loop over all of the (non-terminator) instructions remaining in the
// function, attempting to delete them.
unsigned CurInstructionNum = 0;
for (Module::const_iterator FI = BD.getProgram().begin(),
E = BD.getProgram().end();
FI != E; ++FI)
if (!FI->isDeclaration())
for (Function::const_iterator BI = FI->begin(), E = FI->end(); BI != E;
++BI)
for (BasicBlock::const_iterator I = BI->begin(), E = --BI->end();
I != E; ++I, ++CurInstructionNum) {
if (InstructionsToSkipBeforeDeleting) {
--InstructionsToSkipBeforeDeleting;
} else {
if (BugpointIsInterrupted)
// TODO: Should this be some kind of interrupted error?
return Error::success();
if (I->isEHPad() || I->getType()->isTokenTy() ||
I->isSwiftError())
continue;
outs() << "Checking instruction: " << *I;
std::unique_ptr<Module> M =
BD.deleteInstructionFromProgram(&*I, Simplification);
// Find out if the pass still crashes on this pass...
if (TestFn(BD, M.get())) {
// Yup, it does, we delete the old module, and continue trying
// to reduce the testcase...
BD.setNewProgram(std::move(M));
InstructionsToSkipBeforeDeleting = CurInstructionNum;
goto TryAgain; // I wish I had a multi-level break here!
}
}
}
if (InstructionsToSkipBeforeDeleting) {
InstructionsToSkipBeforeDeleting = 0;
goto TryAgain;
}
} while (Simplification);
BD.EmitProgressBitcode(BD.getProgram(), "reduced-instructions");
return Error::success();
}
/// DebugACrash - Given a predicate that determines whether a component crashes
/// on a program, try to destructively reduce the program while still keeping
/// the predicate true.
static Error DebugACrash(BugDriver &BD, BugTester TestFn) {
// See if we can get away with nuking some of the global variable initializers
// in the program...
if (!NoGlobalRM)
if (Error E = ReduceGlobalInitializers(BD, TestFn))
return E;
// Now try to reduce the number of functions in the module to something small.
std::vector<Function *> Functions;
for (Function &F : BD.getProgram())
if (!F.isDeclaration())
Functions.push_back(&F);
if (Functions.size() > 1 && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to reduce the number of functions "
"in the testcase\n";
unsigned OldSize = Functions.size();
Expected<bool> Result =
ReduceCrashingFunctions(BD, TestFn).reduceList(Functions);
if (Error E = Result.takeError())
return E;
if (Functions.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-function");
}
// Attempt to change conditional branches into unconditional branches to
// eliminate blocks.
if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
std::vector<const BasicBlock *> Blocks;
for (Function &F : BD.getProgram())
for (BasicBlock &BB : F)
Blocks.push_back(&BB);
unsigned OldSize = Blocks.size();
Expected<bool> Result =
ReduceCrashingConditionals(BD, TestFn, true).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
Result = ReduceCrashingConditionals(BD, TestFn, false).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-conditionals");
}
// Attempt to delete entire basic blocks at a time to speed up
// convergence... this actually works by setting the terminator of the blocks
// to a return instruction then running simplifycfg, which can potentially
// shrinks the code dramatically quickly
//
if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
std::vector<const BasicBlock *> Blocks;
for (Function &F : BD.getProgram())
for (BasicBlock &BB : F)
Blocks.push_back(&BB);
unsigned OldSize = Blocks.size();
Expected<bool> Result = ReduceCrashingBlocks(BD, TestFn).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-blocks");
}
if (!DisableSimplifyCFG && !BugpointIsInterrupted) {
std::vector<const BasicBlock *> Blocks;
for (Function &F : BD.getProgram())
for (BasicBlock &BB : F)
Blocks.push_back(&BB);
unsigned OldSize = Blocks.size();
Expected<bool> Result = ReduceSimplifyCFG(BD, TestFn).reduceList(Blocks);
if (Error E = Result.takeError())
return E;
if (Blocks.size() < OldSize)
BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplifycfg");
}
// Attempt to delete instructions using bisection. This should help out nasty
// cases with large basic blocks where the problem is at one end.
if (!BugpointIsInterrupted)
if (Error E = ReduceInsts(BD, TestFn))
return E;
// Attempt to strip debug info metadata.
auto stripMetadata = [&](std::function<bool(Module &)> strip) {
std::unique_ptr<Module> M = CloneModule(BD.getProgram());
strip(*M);
if (TestFn(BD, M.get()))
BD.setNewProgram(std::move(M));
};
if (!NoStripDebugInfo && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to strip the debug info: ";
stripMetadata(StripDebugInfo);
}
if (!NoStripDebugTypeInfo && !BugpointIsInterrupted) {
outs() << "\n*** Attempting to strip the debug type info: ";
stripMetadata(stripNonLineTableDebugInfo);
}
if (!NoNamedMDRM) {
if (!BugpointIsInterrupted) {
// Try to reduce the amount of global metadata (particularly debug info),
// by dropping global named metadata that anchors them
outs() << "\n*** Attempting to remove named metadata: ";
std::vector<std::string> NamedMDNames;
for (auto &NamedMD : BD.getProgram().named_metadata())
NamedMDNames.push_back(NamedMD.getName().str());
Expected<bool> Result =
ReduceCrashingNamedMD(BD, TestFn).reduceList(NamedMDNames);
if (Error E = Result.takeError())
return E;
}
if (!BugpointIsInterrupted) {
// Now that we quickly dropped all the named metadata that doesn't
// contribute to the crash, bisect the operands of the remaining ones
std::vector<const MDNode *> NamedMDOps;
for (auto &NamedMD : BD.getProgram().named_metadata())
for (auto op : NamedMD.operands())
NamedMDOps.push_back(op);
Expected<bool> Result =
ReduceCrashingNamedMDOps(BD, TestFn).reduceList(NamedMDOps);
if (Error E = Result.takeError())
return E;
}
BD.EmitProgressBitcode(BD.getProgram(), "reduced-named-md");
}
// Try to clean up the testcase by running funcresolve and globaldce...
if (!BugpointIsInterrupted) {
outs() << "\n*** Attempting to perform final cleanups: ";
std::unique_ptr<Module> M = CloneModule(BD.getProgram());
M = BD.performFinalCleanups(std::move(M), true);
// Find out if the pass still crashes on the cleaned up program...
if (M && TestFn(BD, M.get()))
BD.setNewProgram(
std::move(M)); // Yup, it does, keep the reduced version...
}
BD.EmitProgressBitcode(BD.getProgram(), "reduced-simplified");
return Error::success();
}
static bool TestForOptimizerCrash(const BugDriver &BD, Module *M) {
return BD.runPasses(*M, BD.getPassesToRun());
}
/// debugOptimizerCrash - This method is called when some pass crashes on input.
/// It attempts to prune down the testcase to something reasonable, and figure
/// out exactly which pass is crashing.
///
Error BugDriver::debugOptimizerCrash(const std::string &ID) {
outs() << "\n*** Debugging optimizer crash!\n";
// Reduce the list of passes which causes the optimizer to crash...
if (!BugpointIsInterrupted && !DontReducePassList) {
Expected<bool> Result = ReducePassList(*this).reduceList(PassesToRun);
if (Error E = Result.takeError())
return E;
}
outs() << "\n*** Found crashing pass"
<< (PassesToRun.size() == 1 ? ": " : "es: ")
<< getPassesString(PassesToRun) << '\n';
EmitProgressBitcode(*Program, ID);
return DebugACrash(*this, TestForOptimizerCrash);
}
static bool TestForCodeGenCrash(const BugDriver &BD, Module *M) {
if (Error E = BD.compileProgram(*M)) {
if (VerboseErrors)
errs() << toString(std::move(E)) << "\n";
else {
consumeError(std::move(E));
errs() << "<crash>\n";
}
return true; // Tool is still crashing.
}
errs() << '\n';
return false;
}
/// debugCodeGeneratorCrash - This method is called when the code generator
/// crashes on an input. It attempts to reduce the input as much as possible
/// while still causing the code generator to crash.
Error BugDriver::debugCodeGeneratorCrash() {
errs() << "*** Debugging code generator crash!\n";
return DebugACrash(*this, TestForCodeGenCrash);
}
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