//===- verify-uselistorder.cpp - The LLVM Modular Optimizer ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Verify that use-list order can be serialized correctly. After reading the
// provided IR, this tool shuffles the use-lists and then writes and reads to a
// separate Module whose use-list orders are compared to the original.
//
// The shuffles are deterministic, but guarantee that use-lists will change.
// The algorithm per iteration is as follows:
//
// 1. Seed the random number generator. The seed is different for each
// shuffle. Shuffle 0 uses default+0, shuffle 1 uses default+1, and so on.
//
// 2. Visit every Value in a deterministic order.
//
// 3. Assign a random number to each Use in the Value's use-list in order.
//
// 4. If the numbers are already in order, reassign numbers until they aren't.
//
// 5. Sort the use-list using Value::sortUseList(), which is a stable sort.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/UseListOrder.h"
#include "llvm/IR/Verifier.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/Support/raw_ostream.h"
#include <random>
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "uselistorder"
static cl::opt<std::string> InputFilename(cl::Positional,
cl::desc("<input bitcode file>"),
cl::init("-"),
cl::value_desc("filename"));
static cl::opt<bool> SaveTemps("save-temps", cl::desc("Save temp files"),
cl::init(false));
static cl::opt<unsigned>
NumShuffles("num-shuffles",
cl::desc("Number of times to shuffle and verify use-lists"),
cl::init(1));
namespace {
struct TempFile {
std::string Filename;
FileRemover Remover;
bool init(const std::string &Ext);
bool writeBitcode(const Module &M) const;
bool writeAssembly(const Module &M) const;
std::unique_ptr<Module> readBitcode(LLVMContext &Context) const;
std::unique_ptr<Module> readAssembly(LLVMContext &Context) const;
};
struct ValueMapping {
DenseMap<const Value *, unsigned> IDs;
std::vector<const Value *> Values;
/// \brief Construct a value mapping for module.
///
/// Creates mapping from every value in \c M to an ID. This mapping includes
/// un-referencable values.
///
/// Every \a Value that gets serialized in some way should be represented
/// here. The order needs to be deterministic, but it's unnecessary to match
/// the value-ids in the bitcode writer.
///
/// All constants that are referenced by other values are included in the
/// mapping, but others -- which wouldn't be serialized -- are not.
ValueMapping(const Module &M);
/// \brief Map a value.
///
/// Maps a value. If it's a constant, maps all of its operands first.
void map(const Value *V);
unsigned lookup(const Value *V) const { return IDs.lookup(V); }
};
} // end namespace
bool TempFile::init(const std::string &Ext) {
SmallVector<char, 64> Vector;
DEBUG(dbgs() << " - create-temp-file\n");
if (auto EC = sys::fs::createTemporaryFile("uselistorder", Ext, Vector)) {
errs() << "verify-uselistorder: error: " << EC.message() << "\n";
return true;
}
assert(!Vector.empty());
Filename.assign(Vector.data(), Vector.data() + Vector.size());
Remover.setFile(Filename, !SaveTemps);
if (SaveTemps)
outs() << " - filename = " << Filename << "\n";
return false;
}
bool TempFile::writeBitcode(const Module &M) const {
DEBUG(dbgs() << " - write bitcode\n");
std::error_code EC;
raw_fd_ostream OS(Filename, EC, sys::fs::F_None);
if (EC) {
errs() << "verify-uselistorder: error: " << EC.message() << "\n";
return true;
}
WriteBitcodeToFile(&M, OS, /* ShouldPreserveUseListOrder */ true);
return false;
}
bool TempFile::writeAssembly(const Module &M) const {
DEBUG(dbgs() << " - write assembly\n");
std::error_code EC;
raw_fd_ostream OS(Filename, EC, sys::fs::F_Text);
if (EC) {
errs() << "verify-uselistorder: error: " << EC.message() << "\n";
return true;
}
M.print(OS, nullptr, /* ShouldPreserveUseListOrder */ true);
return false;
}
std::unique_ptr<Module> TempFile::readBitcode(LLVMContext &Context) const {
DEBUG(dbgs() << " - read bitcode\n");
ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOr =
MemoryBuffer::getFile(Filename);
if (!BufferOr) {
errs() << "verify-uselistorder: error: " << BufferOr.getError().message()
<< "\n";
return nullptr;
}
MemoryBuffer *Buffer = BufferOr.get().get();
ErrorOr<std::unique_ptr<Module>> ModuleOr =
parseBitcodeFile(Buffer->getMemBufferRef(), Context);
if (!ModuleOr) {
errs() << "verify-uselistorder: error: " << ModuleOr.getError().message()
<< "\n";
return nullptr;
}
return std::move(ModuleOr.get());
}
std::unique_ptr<Module> TempFile::readAssembly(LLVMContext &Context) const {
DEBUG(dbgs() << " - read assembly\n");
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyFile(Filename, Err, Context);
if (!M.get())
Err.print("verify-uselistorder", errs());
return M;
}
ValueMapping::ValueMapping(const Module &M) {
// Every value should be mapped, including things like void instructions and
// basic blocks that are kept out of the ValueEnumerator.
//
// The current mapping order makes it easier to debug the tables. It happens
// to be similar to the ID mapping when writing ValueEnumerator, but they
// aren't (and needn't be) in sync.
// Globals.
for (const GlobalVariable &G : M.globals())
map(&G);
for (const GlobalAlias &A : M.aliases())
map(&A);
for (const GlobalIFunc &IF : M.ifuncs())
map(&IF);
for (const Function &F : M)
map(&F);
// Constants used by globals.
for (const GlobalVariable &G : M.globals())
if (G.hasInitializer())
map(G.getInitializer());
for (const GlobalAlias &A : M.aliases())
map(A.getAliasee());
for (const GlobalIFunc &IF : M.ifuncs())
map(IF.getResolver());
for (const Function &F : M) {
if (F.hasPrefixData())
map(F.getPrefixData());
if (F.hasPrologueData())
map(F.getPrologueData());
if (F.hasPersonalityFn())
map(F.getPersonalityFn());
}
// Function bodies.
for (const Function &F : M) {
for (const Argument &A : F.args())
map(&A);
for (const BasicBlock &BB : F)
map(&BB);
for (const BasicBlock &BB : F)
for (const Instruction &I : BB)
map(&I);
// Constants used by instructions.
for (const BasicBlock &BB : F)
for (const Instruction &I : BB)
for (const Value *Op : I.operands())
if ((isa<Constant>(Op) && !isa<GlobalValue>(*Op)) ||
isa<InlineAsm>(Op))
map(Op);
}
}
void ValueMapping::map(const Value *V) {
if (IDs.lookup(V))
return;
if (auto *C = dyn_cast<Constant>(V))
if (!isa<GlobalValue>(C))
for (const Value *Op : C->operands())
map(Op);
Values.push_back(V);
IDs[V] = Values.size();
}
#ifndef NDEBUG
static void dumpMapping(const ValueMapping &VM) {
dbgs() << "value-mapping (size = " << VM.Values.size() << "):\n";
for (unsigned I = 0, E = VM.Values.size(); I != E; ++I) {
dbgs() << " - id = " << I << ", value = ";
VM.Values[I]->dump();
}
}
static void debugValue(const ValueMapping &M, unsigned I, StringRef Desc) {
const Value *V = M.Values[I];
dbgs() << " - " << Desc << " value = ";
V->dump();
for (const Use &U : V->uses()) {
dbgs() << " => use: op = " << U.getOperandNo()
<< ", user-id = " << M.IDs.lookup(U.getUser()) << ", user = ";
U.getUser()->dump();
}
}
static void debugUserMismatch(const ValueMapping &L, const ValueMapping &R,
unsigned I) {
dbgs() << " - fail: user mismatch: ID = " << I << "\n";
debugValue(L, I, "LHS");
debugValue(R, I, "RHS");
dbgs() << "\nlhs-";
dumpMapping(L);
dbgs() << "\nrhs-";
dumpMapping(R);
}
static void debugSizeMismatch(const ValueMapping &L, const ValueMapping &R) {
dbgs() << " - fail: map size: " << L.Values.size()
<< " != " << R.Values.size() << "\n";
dbgs() << "\nlhs-";
dumpMapping(L);
dbgs() << "\nrhs-";
dumpMapping(R);
}
#endif
static bool matches(const ValueMapping &LM, const ValueMapping &RM) {
DEBUG(dbgs() << "compare value maps\n");
if (LM.Values.size() != RM.Values.size()) {
DEBUG(debugSizeMismatch(LM, RM));
return false;
}
// This mapping doesn't include dangling constant users, since those don't
// get serialized. However, checking if users are constant and calling
// isConstantUsed() on every one is very expensive. Instead, just check if
// the user is mapped.
auto skipUnmappedUsers =
[&](Value::const_use_iterator &U, Value::const_use_iterator E,
const ValueMapping &M) {
while (U != E && !M.lookup(U->getUser()))
++U;
};
// Iterate through all values, and check that both mappings have the same
// users.
for (unsigned I = 0, E = LM.Values.size(); I != E; ++I) {
const Value *L = LM.Values[I];
const Value *R = RM.Values[I];
auto LU = L->use_begin(), LE = L->use_end();
auto RU = R->use_begin(), RE = R->use_end();
skipUnmappedUsers(LU, LE, LM);
skipUnmappedUsers(RU, RE, RM);
while (LU != LE) {
if (RU == RE) {
DEBUG(debugUserMismatch(LM, RM, I));
return false;
}
if (LM.lookup(LU->getUser()) != RM.lookup(RU->getUser())) {
DEBUG(debugUserMismatch(LM, RM, I));
return false;
}
if (LU->getOperandNo() != RU->getOperandNo()) {
DEBUG(debugUserMismatch(LM, RM, I));
return false;
}
skipUnmappedUsers(++LU, LE, LM);
skipUnmappedUsers(++RU, RE, RM);
}
if (RU != RE) {
DEBUG(debugUserMismatch(LM, RM, I));
return false;
}
}
return true;
}
static void verifyAfterRoundTrip(const Module &M,
std::unique_ptr<Module> OtherM) {
if (!OtherM)
report_fatal_error("parsing failed");
if (verifyModule(*OtherM, &errs()))
report_fatal_error("verification failed");
if (!matches(ValueMapping(M), ValueMapping(*OtherM)))
report_fatal_error("use-list order changed");
}
static void verifyBitcodeUseListOrder(const Module &M) {
TempFile F;
if (F.init("bc"))
report_fatal_error("failed to initialize bitcode file");
if (F.writeBitcode(M))
report_fatal_error("failed to write bitcode");
LLVMContext Context;
verifyAfterRoundTrip(M, F.readBitcode(Context));
}
static void verifyAssemblyUseListOrder(const Module &M) {
TempFile F;
if (F.init("ll"))
report_fatal_error("failed to initialize assembly file");
if (F.writeAssembly(M))
report_fatal_error("failed to write assembly");
LLVMContext Context;
verifyAfterRoundTrip(M, F.readAssembly(Context));
}
static void verifyUseListOrder(const Module &M) {
outs() << "verify bitcode\n";
verifyBitcodeUseListOrder(M);
outs() << "verify assembly\n";
verifyAssemblyUseListOrder(M);
}
static void shuffleValueUseLists(Value *V, std::minstd_rand0 &Gen,
DenseSet<Value *> &Seen) {
if (!Seen.insert(V).second)
return;
if (auto *C = dyn_cast<Constant>(V))
if (!isa<GlobalValue>(C))
for (Value *Op : C->operands())
shuffleValueUseLists(Op, Gen, Seen);
if (V->use_empty() || std::next(V->use_begin()) == V->use_end())
// Nothing to shuffle for 0 or 1 users.
return;
// Generate random numbers between 10 and 99, which will line up nicely in
// debug output. We're not worried about collisons here.
DEBUG(dbgs() << "V = "; V->dump());
std::uniform_int_distribution<short> Dist(10, 99);
SmallDenseMap<const Use *, short, 16> Order;
auto compareUses =
[&Order](const Use &L, const Use &R) { return Order[&L] < Order[&R]; };
do {
for (const Use &U : V->uses()) {
auto I = Dist(Gen);
Order[&U] = I;
DEBUG(dbgs() << " - order: " << I << ", op = " << U.getOperandNo()
<< ", U = ";
U.getUser()->dump());
}
} while (std::is_sorted(V->use_begin(), V->use_end(), compareUses));
DEBUG(dbgs() << " => shuffle\n");
V->sortUseList(compareUses);
DEBUG({
for (const Use &U : V->uses()) {
dbgs() << " - order: " << Order.lookup(&U)
<< ", op = " << U.getOperandNo() << ", U = ";
U.getUser()->dump();
}
});
}
static void reverseValueUseLists(Value *V, DenseSet<Value *> &Seen) {
if (!Seen.insert(V).second)
return;
if (auto *C = dyn_cast<Constant>(V))
if (!isa<GlobalValue>(C))
for (Value *Op : C->operands())
reverseValueUseLists(Op, Seen);
if (V->use_empty() || std::next(V->use_begin()) == V->use_end())
// Nothing to shuffle for 0 or 1 users.
return;
DEBUG({
dbgs() << "V = ";
V->dump();
for (const Use &U : V->uses()) {
dbgs() << " - order: op = " << U.getOperandNo() << ", U = ";
U.getUser()->dump();
}
dbgs() << " => reverse\n";
});
V->reverseUseList();
DEBUG({
for (const Use &U : V->uses()) {
dbgs() << " - order: op = " << U.getOperandNo() << ", U = ";
U.getUser()->dump();
}
});
}
template <class Changer>
static void changeUseLists(Module &M, Changer changeValueUseList) {
// Visit every value that would be serialized to an IR file.
//
// Globals.
for (GlobalVariable &G : M.globals())
changeValueUseList(&G);
for (GlobalAlias &A : M.aliases())
changeValueUseList(&A);
for (GlobalIFunc &IF : M.ifuncs())
changeValueUseList(&IF);
for (Function &F : M)
changeValueUseList(&F);
// Constants used by globals.
for (GlobalVariable &G : M.globals())
if (G.hasInitializer())
changeValueUseList(G.getInitializer());
for (GlobalAlias &A : M.aliases())
changeValueUseList(A.getAliasee());
for (GlobalIFunc &IF : M.ifuncs())
changeValueUseList(IF.getResolver());
for (Function &F : M) {
if (F.hasPrefixData())
changeValueUseList(F.getPrefixData());
if (F.hasPrologueData())
changeValueUseList(F.getPrologueData());
if (F.hasPersonalityFn())
changeValueUseList(F.getPersonalityFn());
}
// Function bodies.
for (Function &F : M) {
for (Argument &A : F.args())
changeValueUseList(&A);
for (BasicBlock &BB : F)
changeValueUseList(&BB);
for (BasicBlock &BB : F)
for (Instruction &I : BB)
changeValueUseList(&I);
// Constants used by instructions.
for (BasicBlock &BB : F)
for (Instruction &I : BB)
for (Value *Op : I.operands())
if ((isa<Constant>(Op) && !isa<GlobalValue>(*Op)) ||
isa<InlineAsm>(Op))
changeValueUseList(Op);
}
if (verifyModule(M, &errs()))
report_fatal_error("verification failed");
}
static void shuffleUseLists(Module &M, unsigned SeedOffset) {
std::minstd_rand0 Gen(std::minstd_rand0::default_seed + SeedOffset);
DenseSet<Value *> Seen;
changeUseLists(M, [&](Value *V) { shuffleValueUseLists(V, Gen, Seen); });
DEBUG(dbgs() << "\n");
}
static void reverseUseLists(Module &M) {
DenseSet<Value *> Seen;
changeUseLists(M, [&](Value *V) { reverseValueUseLists(V, Seen); });
DEBUG(dbgs() << "\n");
}
int main(int argc, char **argv) {
sys::PrintStackTraceOnErrorSignal(argv[0]);
llvm::PrettyStackTraceProgram X(argc, argv);
// Enable debug stream buffering.
EnableDebugBuffering = true;
llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
LLVMContext Context;
cl::ParseCommandLineOptions(argc, argv,
"llvm tool to verify use-list order\n");
SMDiagnostic Err;
// Load the input module...
std::unique_ptr<Module> M = parseIRFile(InputFilename, Err, Context);
if (!M.get()) {
Err.print(argv[0], errs());
return 1;
}
if (verifyModule(*M, &errs())) {
errs() << argv[0] << ": " << InputFilename
<< ": error: input module is broken!\n";
return 1;
}
// Verify the use lists now and after reversing them.
outs() << "*** verify-uselistorder ***\n";
verifyUseListOrder(*M);
outs() << "reverse\n";
reverseUseLists(*M);
verifyUseListOrder(*M);
for (unsigned I = 0, E = NumShuffles; I != E; ++I) {
outs() << "\n";
// Shuffle with a different (deterministic) seed each time.
outs() << "shuffle (" << I + 1 << " of " << E << ")\n";
shuffleUseLists(*M, I);
// Verify again before and after reversing.
verifyUseListOrder(*M);
outs() << "reverse\n";
reverseUseLists(*M);
verifyUseListOrder(*M);
}
return 0;
}