llvm-project/mlir/lib/ExecutionEngine/ExecutionEngine.cpp

366 lines
14 KiB
C++

//===- ExecutionEngine.cpp - MLIR Execution engine and utils --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the execution engine for MLIR modules based on LLVM Orc
// JIT engine.
//
//===----------------------------------------------------------------------===//
#include "mlir/ExecutionEngine/ExecutionEngine.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/IR/BuiltinOps.h"
#include "mlir/Support/FileUtilities.h"
#include "mlir/Target/LLVMIR/Export.h"
#include "llvm/ExecutionEngine/JITEventListener.h"
#include "llvm/ExecutionEngine/ObjectCache.h"
#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
#include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
#include "llvm/ExecutionEngine/Orc/IRTransformLayer.h"
#include "llvm/ExecutionEngine/Orc/JITTargetMachineBuilder.h"
#include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/ToolOutputFile.h"
#define DEBUG_TYPE "execution-engine"
using namespace mlir;
using llvm::dbgs;
using llvm::Error;
using llvm::errs;
using llvm::Expected;
using llvm::LLVMContext;
using llvm::MemoryBuffer;
using llvm::MemoryBufferRef;
using llvm::Module;
using llvm::SectionMemoryManager;
using llvm::StringError;
using llvm::Triple;
using llvm::orc::DynamicLibrarySearchGenerator;
using llvm::orc::ExecutionSession;
using llvm::orc::IRCompileLayer;
using llvm::orc::JITTargetMachineBuilder;
using llvm::orc::MangleAndInterner;
using llvm::orc::RTDyldObjectLinkingLayer;
using llvm::orc::SymbolMap;
using llvm::orc::ThreadSafeModule;
using llvm::orc::TMOwningSimpleCompiler;
/// Wrap a string into an llvm::StringError.
static Error make_string_error(const Twine &message) {
return llvm::make_error<StringError>(message.str(),
llvm::inconvertibleErrorCode());
}
void SimpleObjectCache::notifyObjectCompiled(const Module *M,
MemoryBufferRef ObjBuffer) {
cachedObjects[M->getModuleIdentifier()] = MemoryBuffer::getMemBufferCopy(
ObjBuffer.getBuffer(), ObjBuffer.getBufferIdentifier());
}
std::unique_ptr<MemoryBuffer> SimpleObjectCache::getObject(const Module *M) {
auto I = cachedObjects.find(M->getModuleIdentifier());
if (I == cachedObjects.end()) {
LLVM_DEBUG(dbgs() << "No object for " << M->getModuleIdentifier()
<< " in cache. Compiling.\n");
return nullptr;
}
LLVM_DEBUG(dbgs() << "Object for " << M->getModuleIdentifier()
<< " loaded from cache.\n");
return MemoryBuffer::getMemBuffer(I->second->getMemBufferRef());
}
void SimpleObjectCache::dumpToObjectFile(StringRef outputFilename) {
// Set up the output file.
std::string errorMessage;
auto file = openOutputFile(outputFilename, &errorMessage);
if (!file) {
llvm::errs() << errorMessage << "\n";
return;
}
// Dump the object generated for a single module to the output file.
assert(cachedObjects.size() == 1 && "Expected only one object entry.");
auto &cachedObject = cachedObjects.begin()->second;
file->os() << cachedObject->getBuffer();
file->keep();
}
void ExecutionEngine::dumpToObjectFile(StringRef filename) {
cache->dumpToObjectFile(filename);
}
void ExecutionEngine::registerSymbols(
llvm::function_ref<SymbolMap(MangleAndInterner)> symbolMap) {
auto &mainJitDylib = jit->getMainJITDylib();
cantFail(mainJitDylib.define(
absoluteSymbols(symbolMap(llvm::orc::MangleAndInterner(
mainJitDylib.getExecutionSession(), jit->getDataLayout())))));
}
// Setup LLVM target triple from the current machine.
bool ExecutionEngine::setupTargetTriple(Module *llvmModule) {
// Setup the machine properties from the current architecture.
auto targetTriple = llvm::sys::getDefaultTargetTriple();
std::string errorMessage;
auto target = llvm::TargetRegistry::lookupTarget(targetTriple, errorMessage);
if (!target) {
errs() << "NO target: " << errorMessage << "\n";
return true;
}
std::string cpu(llvm::sys::getHostCPUName());
llvm::SubtargetFeatures features;
llvm::StringMap<bool> hostFeatures;
if (llvm::sys::getHostCPUFeatures(hostFeatures))
for (auto &f : hostFeatures)
features.AddFeature(f.first(), f.second);
std::unique_ptr<llvm::TargetMachine> machine(target->createTargetMachine(
targetTriple, cpu, features.getString(), {}, {}));
if (!machine) {
errs() << "Unable to create target machine\n";
return true;
}
llvmModule->setDataLayout(machine->createDataLayout());
llvmModule->setTargetTriple(targetTriple);
return false;
}
static std::string makePackedFunctionName(StringRef name) {
return "_mlir_" + name.str();
}
// For each function in the LLVM module, define an interface function that wraps
// all the arguments of the original function and all its results into an i8**
// pointer to provide a unified invocation interface.
static void packFunctionArguments(Module *module) {
auto &ctx = module->getContext();
llvm::IRBuilder<> builder(ctx);
DenseSet<llvm::Function *> interfaceFunctions;
for (auto &func : module->getFunctionList()) {
if (func.isDeclaration()) {
continue;
}
if (interfaceFunctions.count(&func)) {
continue;
}
// Given a function `foo(<...>)`, define the interface function
// `mlir_foo(i8**)`.
auto newType = llvm::FunctionType::get(
builder.getVoidTy(), builder.getInt8PtrTy()->getPointerTo(),
/*isVarArg=*/false);
auto newName = makePackedFunctionName(func.getName());
auto funcCst = module->getOrInsertFunction(newName, newType);
llvm::Function *interfaceFunc = cast<llvm::Function>(funcCst.getCallee());
interfaceFunctions.insert(interfaceFunc);
// Extract the arguments from the type-erased argument list and cast them to
// the proper types.
auto bb = llvm::BasicBlock::Create(ctx);
bb->insertInto(interfaceFunc);
builder.SetInsertPoint(bb);
llvm::Value *argList = interfaceFunc->arg_begin();
SmallVector<llvm::Value *, 8> args;
args.reserve(llvm::size(func.args()));
for (auto &indexedArg : llvm::enumerate(func.args())) {
llvm::Value *argIndex = llvm::Constant::getIntegerValue(
builder.getInt64Ty(), APInt(64, indexedArg.index()));
llvm::Value *argPtrPtr = builder.CreateGEP(
builder.getInt8PtrTy(), argList, argIndex);
llvm::Value *argPtr = builder.CreateLoad(builder.getInt8PtrTy(),
argPtrPtr);
llvm::Type *argTy = indexedArg.value().getType();
argPtr = builder.CreateBitCast(argPtr, argTy->getPointerTo());
llvm::Value *arg = builder.CreateLoad(argTy, argPtr);
args.push_back(arg);
}
// Call the implementation function with the extracted arguments.
llvm::Value *result = builder.CreateCall(&func, args);
// Assuming the result is one value, potentially of type `void`.
if (!result->getType()->isVoidTy()) {
llvm::Value *retIndex = llvm::Constant::getIntegerValue(
builder.getInt64Ty(), APInt(64, llvm::size(func.args())));
llvm::Value *retPtrPtr =
builder.CreateGEP(builder.getInt8PtrTy(), argList, retIndex);
llvm::Value *retPtr = builder.CreateLoad(builder.getInt8PtrTy(),
retPtrPtr);
retPtr = builder.CreateBitCast(retPtr, result->getType()->getPointerTo());
builder.CreateStore(result, retPtr);
}
// The interface function returns void.
builder.CreateRetVoid();
}
}
ExecutionEngine::ExecutionEngine(bool enableObjectCache,
bool enableGDBNotificationListener,
bool enablePerfNotificationListener)
: cache(enableObjectCache ? new SimpleObjectCache() : nullptr),
gdbListener(enableGDBNotificationListener
? llvm::JITEventListener::createGDBRegistrationListener()
: nullptr),
perfListener(enablePerfNotificationListener
? llvm::JITEventListener::createPerfJITEventListener()
: nullptr) {}
Expected<std::unique_ptr<ExecutionEngine>> ExecutionEngine::create(
ModuleOp m,
llvm::function_ref<std::unique_ptr<llvm::Module>(ModuleOp,
llvm::LLVMContext &)>
llvmModuleBuilder,
llvm::function_ref<Error(llvm::Module *)> transformer,
Optional<llvm::CodeGenOpt::Level> jitCodeGenOptLevel,
ArrayRef<StringRef> sharedLibPaths, bool enableObjectCache,
bool enableGDBNotificationListener, bool enablePerfNotificationListener) {
auto engine = std::make_unique<ExecutionEngine>(
enableObjectCache, enableGDBNotificationListener,
enablePerfNotificationListener);
std::unique_ptr<llvm::LLVMContext> ctx(new llvm::LLVMContext);
auto llvmModule = llvmModuleBuilder ? llvmModuleBuilder(m, *ctx)
: translateModuleToLLVMIR(m, *ctx);
if (!llvmModule)
return make_string_error("could not convert to LLVM IR");
// FIXME: the triple should be passed to the translation or dialect conversion
// instead of this. Currently, the LLVM module created above has no triple
// associated with it.
setupTargetTriple(llvmModule.get());
packFunctionArguments(llvmModule.get());
auto dataLayout = llvmModule->getDataLayout();
// Callback to create the object layer with symbol resolution to current
// process and dynamically linked libraries.
auto objectLinkingLayerCreator = [&](ExecutionSession &session,
const Triple &TT) {
auto objectLayer = std::make_unique<RTDyldObjectLinkingLayer>(
session, []() { return std::make_unique<SectionMemoryManager>(); });
// Register JIT event listeners if they are enabled.
if (engine->gdbListener)
objectLayer->registerJITEventListener(*engine->gdbListener);
if (engine->perfListener)
objectLayer->registerJITEventListener(*engine->perfListener);
// COFF format binaries (Windows) need special handling to deal with
// exported symbol visibility.
// cf llvm/lib/ExecutionEngine/Orc/LLJIT.cpp LLJIT::createObjectLinkingLayer
llvm::Triple targetTriple(llvm::Twine(llvmModule->getTargetTriple()));
if (targetTriple.isOSBinFormatCOFF()) {
objectLayer->setOverrideObjectFlagsWithResponsibilityFlags(true);
objectLayer->setAutoClaimResponsibilityForObjectSymbols(true);
}
// Resolve symbols from shared libraries.
for (auto libPath : sharedLibPaths) {
auto mb = llvm::MemoryBuffer::getFile(libPath);
if (!mb) {
errs() << "Failed to create MemoryBuffer for: " << libPath
<< "\nError: " << mb.getError().message() << "\n";
continue;
}
auto &JD = session.createBareJITDylib(std::string(libPath));
auto loaded = DynamicLibrarySearchGenerator::Load(
libPath.data(), dataLayout.getGlobalPrefix());
if (!loaded) {
errs() << "Could not load " << libPath << ":\n " << loaded.takeError()
<< "\n";
continue;
}
JD.addGenerator(std::move(*loaded));
cantFail(objectLayer->add(JD, std::move(mb.get())));
}
return objectLayer;
};
// Callback to inspect the cache and recompile on demand. This follows Lang's
// LLJITWithObjectCache example.
auto compileFunctionCreator = [&](JITTargetMachineBuilder JTMB)
-> Expected<std::unique_ptr<IRCompileLayer::IRCompiler>> {
if (jitCodeGenOptLevel)
JTMB.setCodeGenOptLevel(jitCodeGenOptLevel.getValue());
auto TM = JTMB.createTargetMachine();
if (!TM)
return TM.takeError();
return std::make_unique<TMOwningSimpleCompiler>(std::move(*TM),
engine->cache.get());
};
// Create the LLJIT by calling the LLJITBuilder with 2 callbacks.
auto jit =
cantFail(llvm::orc::LLJITBuilder()
.setCompileFunctionCreator(compileFunctionCreator)
.setObjectLinkingLayerCreator(objectLinkingLayerCreator)
.create());
// Add a ThreadSafemodule to the engine and return.
ThreadSafeModule tsm(std::move(llvmModule), std::move(ctx));
if (transformer)
cantFail(tsm.withModuleDo(
[&](llvm::Module &module) { return transformer(&module); }));
cantFail(jit->addIRModule(std::move(tsm)));
engine->jit = std::move(jit);
// Resolve symbols that are statically linked in the current process.
llvm::orc::JITDylib &mainJD = engine->jit->getMainJITDylib();
mainJD.addGenerator(
cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
dataLayout.getGlobalPrefix())));
return std::move(engine);
}
Expected<void (*)(void **)> ExecutionEngine::lookup(StringRef name) const {
auto expectedSymbol = jit->lookup(makePackedFunctionName(name));
// JIT lookup may return an Error referring to strings stored internally by
// the JIT. If the Error outlives the ExecutionEngine, it would want have a
// dangling reference, which is currently caught by an assertion inside JIT
// thanks to hand-rolled reference counting. Rewrap the error message into a
// string before returning. Alternatively, ORC JIT should consider copying
// the string into the error message.
if (!expectedSymbol) {
std::string errorMessage;
llvm::raw_string_ostream os(errorMessage);
llvm::handleAllErrors(expectedSymbol.takeError(),
[&os](llvm::ErrorInfoBase &ei) { ei.log(os); });
return make_string_error(os.str());
}
auto rawFPtr = expectedSymbol->getAddress();
auto fptr = reinterpret_cast<void (*)(void **)>(rawFPtr);
if (!fptr)
return make_string_error("looked up function is null");
return fptr;
}
Error ExecutionEngine::invokePacked(StringRef name,
MutableArrayRef<void *> args) {
auto expectedFPtr = lookup(name);
if (!expectedFPtr)
return expectedFPtr.takeError();
auto fptr = *expectedFPtr;
(*fptr)(args.data());
return Error::success();
}