// 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 and somewhat naive. On a given shuffle, some
-// use-lists will not change at all. The algorithm per iteration is as follows:
+// 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.
//
// 3. Assign a random number to each Use in the Value's use-list in order.
//
-// 4. Sort the use-list using Value::sortUseList(), which is a stable sort.
+// 4. If the numbers are already in order, reassign numbers until they aren't.
//
-// Shuffling a larger number of times provides a better statistical guarantee
-// that each use-list has changed at least once.
+// 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/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 "use-list-order"
+#define DEBUG_TYPE "uselistorder"
static cl::opt<std::string> InputFilename(cl::Positional,
cl::desc("<input bitcode file>"),
static cl::opt<unsigned>
NumShuffles("num-shuffles",
cl::desc("Number of times to shuffle and verify use-lists"),
- cl::init(5));
+ cl::init(1));
namespace {
bool TempFile::init(const std::string &Ext) {
SmallVector<char, 64> Vector;
DEBUG(dbgs() << " - create-temp-file\n");
- if (auto EC = sys::fs::createTemporaryFile("use-list-order", Ext, Vector)) {
- (void)EC;
- DEBUG(dbgs() << "error: " << EC.message() << "\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);
- DEBUG(dbgs() << " - filename = " << Filename << "\n");
+ if (SaveTemps)
+ outs() << " - filename = " << Filename << "\n";
return false;
}
bool TempFile::writeBitcode(const Module &M) const {
DEBUG(dbgs() << " - write bitcode\n");
- std::string ErrorInfo;
- raw_fd_ostream OS(Filename.c_str(), ErrorInfo, sys::fs::F_None);
- if (!ErrorInfo.empty()) {
- DEBUG(dbgs() << "error: " << ErrorInfo << "\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);
+ WriteBitcodeToFile(&M, OS, /* ShouldPreserveUseListOrder */ true);
return false;
}
bool TempFile::writeAssembly(const Module &M) const {
DEBUG(dbgs() << " - write assembly\n");
- std::string ErrorInfo;
- raw_fd_ostream OS(Filename.c_str(), ErrorInfo, sys::fs::F_Text);
- if (!ErrorInfo.empty()) {
- DEBUG(dbgs() << "error: " << ErrorInfo << "\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;
}
- OS << M;
+ M.print(OS, nullptr, /* ShouldPreserveUseListOrder */ true);
return false;
}
ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOr =
MemoryBuffer::getFile(Filename);
if (!BufferOr) {
- DEBUG(dbgs() << "error: " << BufferOr.getError().message() << "\n");
+ errs() << "verify-uselistorder: error: " << BufferOr.getError().message()
+ << "\n";
return nullptr;
}
MemoryBuffer *Buffer = BufferOr.get().get();
- ErrorOr<Module *> ModuleOr = parseBitcodeFile(Buffer, Context);
+ ErrorOr<std::unique_ptr<Module>> ModuleOr =
+ parseBitcodeFile(Buffer->getMemBufferRef(), Context);
if (!ModuleOr) {
- DEBUG(dbgs() << "error: " << ModuleOr.getError().message() << "\n");
+ errs() << "verify-uselistorder: error: " << ModuleOr.getError().message()
+ << "\n";
return nullptr;
}
- return std::unique_ptr<Module>(ModuleOr.get());
+ 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));
+ std::unique_ptr<Module> M = parseAssemblyFile(Filename, Err, Context);
if (!M.get())
- DEBUG(dbgs() << "error: "; Err.print("verify-use-list-order", dbgs()));
+ Err.print("verify-uselistorder", errs());
return M;
}
map(G.getInitializer());
for (const GlobalAlias &A : M.aliases())
map(A.getAliasee());
- for (const Function &F : M)
+ 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) {
return true;
}
-static bool verifyBitcodeUseListOrder(const Module &M) {
- DEBUG(dbgs() << "*** verify-use-list-order: bitcode ***\n");
+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"))
- return false;
+ report_fatal_error("failed to initialize bitcode file");
if (F.writeBitcode(M))
- return false;
+ report_fatal_error("failed to write bitcode");
LLVMContext Context;
- std::unique_ptr<Module> OtherM = F.readBitcode(Context);
- if (!OtherM)
- return false;
-
- return matches(ValueMapping(M), ValueMapping(*OtherM));
+ verifyAfterRoundTrip(M, F.readBitcode(Context));
}
-static bool verifyAssemblyUseListOrder(const Module &M) {
- DEBUG(dbgs() << "*** verify-use-list-order: assembly ***\n");
+static void verifyAssemblyUseListOrder(const Module &M) {
TempFile F;
if (F.init("ll"))
- return false;
+ report_fatal_error("failed to initialize assembly file");
if (F.writeAssembly(M))
- return false;
+ report_fatal_error("failed to write assembly");
LLVMContext Context;
- std::unique_ptr<Module> OtherM = F.readAssembly(Context);
- if (!OtherM)
- return false;
+ 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;
- return matches(ValueMapping(M), ValueMapping(*OtherM));
+ 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 (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 (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) {
SMDiagnostic Err;
// Load the input module...
- std::unique_ptr<Module> M;
- M.reset(ParseIRFile(InputFilename, Err, Context));
+ std::unique_ptr<Module> M = parseIRFile(InputFilename, Err, Context);
if (!M.get()) {
Err.print(argv[0], errs());
return 1;
}
-
- DEBUG(dbgs() << "*** verify-use-list-order ***\n");
- if (!shouldPreserveBitcodeUseListOrder()) {
- // Can't verify if order isn't preserved.
- DEBUG(dbgs() << "warning: cannot verify bitcode; "
- "try -preserve-bc-use-list-order\n");
- return 0;
+ 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) {
- DEBUG(dbgs() << "*** iteration: " << I << " ***\n");
+ outs() << "\n";
- // Shuffle with a different seed each time so that use-lists that aren't
- // modified the first time are likely to be modified the next time.
+ // Shuffle with a different (deterministic) seed each time.
+ outs() << "shuffle (" << I + 1 << " of " << E << ")\n";
shuffleUseLists(*M, I);
- if (!verifyBitcodeUseListOrder(*M))
- report_fatal_error("bitcode use-list order changed");
- if (shouldPreserveAssemblyUseListOrder())
- if (!verifyAssemblyUseListOrder(*M))
- report_fatal_error("assembly use-list order changed");
+ // Verify again before and after reversing.
+ verifyUseListOrder(*M);
+ outs() << "reverse\n";
+ reverseUseLists(*M);
+ verifyUseListOrder(*M);
}
return 0;
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