f8fcff5a9d
Lower from Async dialect to LLVM by converting async regions attached to `async.execute` operations into LLVM coroutines (https://llvm.org/docs/Coroutines.html): 1. Outline all async regions to functions 2. Add LLVM coro intrinsics to mark coroutine begin/end 3. Use MLIR conversion framework to convert all remaining async types and ops to LLVM + Async runtime function calls All `async.await` operations inside async regions converted to coroutine suspension points. Await operation outside of a coroutine converted to the blocking wait operations. Implement simple runtime to support concurrent execution of coroutines. Reviewed By: herhut Differential Revision: https://reviews.llvm.org/D89292
734 lines
27 KiB
C++
734 lines
27 KiB
C++
//===- AsyncToLLVM.cpp - Convert Async to LLVM dialect --------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "mlir/Conversion/AsyncToLLVM/AsyncToLLVM.h"
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#include "../PassDetail.h"
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#include "mlir/Dialect/Async/IR/Async.h"
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#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
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#include "mlir/Dialect/StandardOps/IR/Ops.h"
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#include "mlir/IR/BlockAndValueMapping.h"
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#include "mlir/IR/Builders.h"
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#include "mlir/IR/TypeUtilities.h"
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#include "mlir/Pass/Pass.h"
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#include "mlir/Transforms/DialectConversion.h"
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#include "mlir/Transforms/RegionUtils.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/Support/FormatVariadic.h"
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#define DEBUG_TYPE "convert-async-to-llvm"
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using namespace mlir;
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using namespace mlir::async;
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// Prefix for functions outlined from `async.execute` op regions.
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static constexpr const char kAsyncFnPrefix[] = "async_execute_fn";
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//===----------------------------------------------------------------------===//
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// Async Runtime C API declaration.
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//===----------------------------------------------------------------------===//
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static constexpr const char *kCreateToken = "mlirAsyncRuntimeCreateToken";
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static constexpr const char *kEmplaceToken = "mlirAsyncRuntimeEmplaceToken";
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static constexpr const char *kAwaitToken = "mlirAsyncRuntimeAwaitToken";
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static constexpr const char *kExecute = "mlirAsyncRuntimeExecute";
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static constexpr const char *kAwaitAndExecute =
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"mlirAsyncRuntimeAwaitTokenAndExecute";
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namespace {
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// Async Runtime API function types.
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struct AsyncAPI {
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static FunctionType createTokenFunctionType(MLIRContext *ctx) {
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return FunctionType::get({}, {TokenType::get(ctx)}, ctx);
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}
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static FunctionType emplaceTokenFunctionType(MLIRContext *ctx) {
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return FunctionType::get({TokenType::get(ctx)}, {}, ctx);
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}
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static FunctionType awaitTokenFunctionType(MLIRContext *ctx) {
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return FunctionType::get({TokenType::get(ctx)}, {}, ctx);
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}
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static FunctionType executeFunctionType(MLIRContext *ctx) {
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auto hdl = LLVM::LLVMType::getInt8PtrTy(ctx);
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auto resume = resumeFunctionType(ctx).getPointerTo();
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return FunctionType::get({hdl, resume}, {}, ctx);
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}
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static FunctionType awaitAndExecuteFunctionType(MLIRContext *ctx) {
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auto hdl = LLVM::LLVMType::getInt8PtrTy(ctx);
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auto resume = resumeFunctionType(ctx).getPointerTo();
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return FunctionType::get({TokenType::get(ctx), hdl, resume}, {}, ctx);
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}
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// Auxiliary coroutine resume intrinsic wrapper.
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static LLVM::LLVMType resumeFunctionType(MLIRContext *ctx) {
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auto voidTy = LLVM::LLVMType::getVoidTy(ctx);
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auto i8Ptr = LLVM::LLVMType::getInt8PtrTy(ctx);
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return LLVM::LLVMType::getFunctionTy(voidTy, {i8Ptr}, false);
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}
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};
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} // namespace
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// Adds Async Runtime C API declarations to the module.
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static void addAsyncRuntimeApiDeclarations(ModuleOp module) {
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auto builder = OpBuilder::atBlockTerminator(module.getBody());
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MLIRContext *ctx = module.getContext();
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Location loc = module.getLoc();
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if (!module.lookupSymbol(kCreateToken))
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builder.create<FuncOp>(loc, kCreateToken,
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AsyncAPI::createTokenFunctionType(ctx));
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if (!module.lookupSymbol(kEmplaceToken))
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builder.create<FuncOp>(loc, kEmplaceToken,
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AsyncAPI::emplaceTokenFunctionType(ctx));
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if (!module.lookupSymbol(kAwaitToken))
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builder.create<FuncOp>(loc, kAwaitToken,
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AsyncAPI::awaitTokenFunctionType(ctx));
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if (!module.lookupSymbol(kExecute))
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builder.create<FuncOp>(loc, kExecute, AsyncAPI::executeFunctionType(ctx));
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if (!module.lookupSymbol(kAwaitAndExecute))
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builder.create<FuncOp>(loc, kAwaitAndExecute,
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AsyncAPI::awaitAndExecuteFunctionType(ctx));
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}
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//===----------------------------------------------------------------------===//
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// LLVM coroutines intrinsics declarations.
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//===----------------------------------------------------------------------===//
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static constexpr const char *kCoroId = "llvm.coro.id";
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static constexpr const char *kCoroSizeI64 = "llvm.coro.size.i64";
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static constexpr const char *kCoroBegin = "llvm.coro.begin";
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static constexpr const char *kCoroSave = "llvm.coro.save";
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static constexpr const char *kCoroSuspend = "llvm.coro.suspend";
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static constexpr const char *kCoroEnd = "llvm.coro.end";
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static constexpr const char *kCoroFree = "llvm.coro.free";
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static constexpr const char *kCoroResume = "llvm.coro.resume";
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/// Adds coroutine intrinsics declarations to the module.
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static void addCoroutineIntrinsicsDeclarations(ModuleOp module) {
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using namespace mlir::LLVM;
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MLIRContext *ctx = module.getContext();
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Location loc = module.getLoc();
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OpBuilder builder(module.getBody()->getTerminator());
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auto token = LLVMTokenType::get(ctx);
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auto voidTy = LLVMType::getVoidTy(ctx);
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auto i8 = LLVMType::getInt8Ty(ctx);
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auto i1 = LLVMType::getInt1Ty(ctx);
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auto i32 = LLVMType::getInt32Ty(ctx);
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auto i64 = LLVMType::getInt64Ty(ctx);
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auto i8Ptr = LLVMType::getInt8PtrTy(ctx);
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if (!module.lookupSymbol(kCoroId))
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builder.create<LLVMFuncOp>(
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loc, kCoroId,
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LLVMType::getFunctionTy(token, {i32, i8Ptr, i8Ptr, i8Ptr}, false));
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if (!module.lookupSymbol(kCoroSizeI64))
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builder.create<LLVMFuncOp>(loc, kCoroSizeI64,
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LLVMType::getFunctionTy(i64, false));
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if (!module.lookupSymbol(kCoroBegin))
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builder.create<LLVMFuncOp>(
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loc, kCoroBegin, LLVMType::getFunctionTy(i8Ptr, {token, i8Ptr}, false));
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if (!module.lookupSymbol(kCoroSave))
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builder.create<LLVMFuncOp>(loc, kCoroSave,
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LLVMType::getFunctionTy(token, i8Ptr, false));
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if (!module.lookupSymbol(kCoroSuspend))
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builder.create<LLVMFuncOp>(loc, kCoroSuspend,
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LLVMType::getFunctionTy(i8, {token, i1}, false));
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if (!module.lookupSymbol(kCoroEnd))
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builder.create<LLVMFuncOp>(loc, kCoroEnd,
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LLVMType::getFunctionTy(i1, {i8Ptr, i1}, false));
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if (!module.lookupSymbol(kCoroFree))
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builder.create<LLVMFuncOp>(
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loc, kCoroFree, LLVMType::getFunctionTy(i8Ptr, {token, i8Ptr}, false));
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if (!module.lookupSymbol(kCoroResume))
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builder.create<LLVMFuncOp>(loc, kCoroResume,
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LLVMType::getFunctionTy(voidTy, i8Ptr, false));
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}
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//===----------------------------------------------------------------------===//
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// Add malloc/free declarations to the module.
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//===----------------------------------------------------------------------===//
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static constexpr const char *kMalloc = "malloc";
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static constexpr const char *kFree = "free";
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/// Adds malloc/free declarations to the module.
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static void addCRuntimeDeclarations(ModuleOp module) {
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using namespace mlir::LLVM;
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MLIRContext *ctx = module.getContext();
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Location loc = module.getLoc();
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OpBuilder builder(module.getBody()->getTerminator());
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auto voidTy = LLVMType::getVoidTy(ctx);
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auto i64 = LLVMType::getInt64Ty(ctx);
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auto i8Ptr = LLVMType::getInt8PtrTy(ctx);
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if (!module.lookupSymbol(kMalloc))
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builder.create<LLVM::LLVMFuncOp>(
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loc, kMalloc, LLVMType::getFunctionTy(i8Ptr, {i64}, false));
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if (!module.lookupSymbol(kFree))
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builder.create<LLVM::LLVMFuncOp>(
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loc, kFree, LLVMType::getFunctionTy(voidTy, i8Ptr, false));
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}
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//===----------------------------------------------------------------------===//
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// Coroutine resume function wrapper.
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//===----------------------------------------------------------------------===//
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static constexpr const char *kResume = "__resume";
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// A function that takes a coroutine handle and calls a `llvm.coro.resume`
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// intrinsics. We need this function to be able to pass it to the async
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// runtime execute API.
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static void addResumeFunction(ModuleOp module) {
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MLIRContext *ctx = module.getContext();
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OpBuilder moduleBuilder(module.getBody()->getTerminator());
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Location loc = module.getLoc();
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if (module.lookupSymbol(kResume))
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return;
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auto voidTy = LLVM::LLVMType::getVoidTy(ctx);
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auto i8Ptr = LLVM::LLVMType::getInt8PtrTy(ctx);
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auto resumeOp = moduleBuilder.create<LLVM::LLVMFuncOp>(
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loc, kResume, LLVM::LLVMFunctionType::get(voidTy, {i8Ptr}));
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SymbolTable::setSymbolVisibility(resumeOp, SymbolTable::Visibility::Private);
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auto *block = resumeOp.addEntryBlock();
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OpBuilder blockBuilder = OpBuilder::atBlockEnd(block);
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blockBuilder.create<LLVM::CallOp>(loc, Type(),
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blockBuilder.getSymbolRefAttr(kCoroResume),
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resumeOp.getArgument(0));
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blockBuilder.create<LLVM::ReturnOp>(loc, ValueRange());
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}
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//===----------------------------------------------------------------------===//
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// async.execute op outlining to the coroutine functions.
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//===----------------------------------------------------------------------===//
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// Function targeted for coroutine transformation has two additional blocks at
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// the end: coroutine cleanup and coroutine suspension.
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//
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// async.await op lowering additionaly creates a resume block for each
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// operation to enable non-blocking waiting via coroutine suspension.
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namespace {
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struct CoroMachinery {
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Value asyncToken;
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Value coroHandle;
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Block *cleanup;
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Block *suspend;
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};
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} // namespace
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// Builds an coroutine template compatible with LLVM coroutines lowering.
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//
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// - `entry` block sets up the coroutine.
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// - `cleanup` block cleans up the coroutine state.
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// - `suspend block after the @llvm.coro.end() defines what value will be
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// returned to the initial caller of a coroutine. Everything before the
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// @llvm.coro.end() will be executed at every suspension point.
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//
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// Coroutine structure (only the important bits):
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//
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// func @async_execute_fn(<function-arguments>) -> !async.token {
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// ^entryBlock(<function-arguments>):
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// %token = <async token> : !async.token // create async runtime token
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// %hdl = llvm.call @llvm.coro.id(...) // create a coroutine handle
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// br ^cleanup
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//
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// ^cleanup:
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// llvm.call @llvm.coro.free(...) // delete coroutine state
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// br ^suspend
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//
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// ^suspend:
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// llvm.call @llvm.coro.end(...) // marks the end of a coroutine
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// return %token : !async.token
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// }
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//
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// The actual code for the async.execute operation body region will be inserted
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// before the entry block terminator.
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//
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//
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static CoroMachinery setupCoroMachinery(FuncOp func) {
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assert(func.getBody().empty() && "Function must have empty body");
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MLIRContext *ctx = func.getContext();
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auto token = LLVM::LLVMTokenType::get(ctx);
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auto i1 = LLVM::LLVMType::getInt1Ty(ctx);
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auto i32 = LLVM::LLVMType::getInt32Ty(ctx);
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auto i64 = LLVM::LLVMType::getInt64Ty(ctx);
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auto i8Ptr = LLVM::LLVMType::getInt8PtrTy(ctx);
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Block *entryBlock = func.addEntryBlock();
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Location loc = func.getBody().getLoc();
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OpBuilder builder = OpBuilder::atBlockBegin(entryBlock);
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// ------------------------------------------------------------------------ //
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// Allocate async tokens/values that we will return from a ramp function.
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// ------------------------------------------------------------------------ //
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auto createToken =
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builder.create<CallOp>(loc, kCreateToken, TokenType::get(ctx));
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// ------------------------------------------------------------------------ //
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// Initialize coroutine: allocate frame, get coroutine handle.
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// ------------------------------------------------------------------------ //
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// Constants for initializing coroutine frame.
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auto constZero =
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builder.create<LLVM::ConstantOp>(loc, i32, builder.getI32IntegerAttr(0));
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auto constFalse =
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builder.create<LLVM::ConstantOp>(loc, i1, builder.getBoolAttr(false));
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auto nullPtr = builder.create<LLVM::NullOp>(loc, i8Ptr);
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// Get coroutine id: @llvm.coro.id
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auto coroId = builder.create<LLVM::CallOp>(
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loc, token, builder.getSymbolRefAttr(kCoroId),
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ValueRange({constZero, nullPtr, nullPtr, nullPtr}));
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// Get coroutine frame size: @llvm.coro.size.i64
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auto coroSize = builder.create<LLVM::CallOp>(
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loc, i64, builder.getSymbolRefAttr(kCoroSizeI64), ValueRange());
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// Allocate memory for coroutine frame.
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auto coroAlloc = builder.create<LLVM::CallOp>(
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loc, i8Ptr, builder.getSymbolRefAttr(kMalloc),
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ValueRange(coroSize.getResult(0)));
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// Begin a coroutine: @llvm.coro.begin
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auto coroHdl = builder.create<LLVM::CallOp>(
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loc, i8Ptr, builder.getSymbolRefAttr(kCoroBegin),
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ValueRange({coroId.getResult(0), coroAlloc.getResult(0)}));
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Block *cleanupBlock = func.addBlock();
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Block *suspendBlock = func.addBlock();
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// ------------------------------------------------------------------------ //
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// Coroutine cleanup block: deallocate coroutine frame, free the memory.
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// ------------------------------------------------------------------------ //
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builder.setInsertionPointToStart(cleanupBlock);
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// Get a pointer to the coroutine frame memory: @llvm.coro.free.
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auto coroMem = builder.create<LLVM::CallOp>(
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loc, i8Ptr, builder.getSymbolRefAttr(kCoroFree),
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ValueRange({coroId.getResult(0), coroHdl.getResult(0)}));
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// Free the memory.
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builder.create<LLVM::CallOp>(loc, Type(), builder.getSymbolRefAttr(kFree),
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ValueRange(coroMem.getResult(0)));
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// Branch into the suspend block.
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builder.create<BranchOp>(loc, suspendBlock);
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// ------------------------------------------------------------------------ //
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// Coroutine suspend block: mark the end of a coroutine and return allocated
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// async token.
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// ------------------------------------------------------------------------ //
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builder.setInsertionPointToStart(suspendBlock);
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// Mark the end of a coroutine: @llvm.coro.end.
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builder.create<LLVM::CallOp>(loc, i1, builder.getSymbolRefAttr(kCoroEnd),
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ValueRange({coroHdl.getResult(0), constFalse}));
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// Return created `async.token` from the suspend block. This will be the
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// return value of a coroutine ramp function.
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builder.create<ReturnOp>(loc, createToken.getResult(0));
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// Branch from the entry block to the cleanup block to create a valid CFG.
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builder.setInsertionPointToEnd(entryBlock);
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builder.create<BranchOp>(loc, cleanupBlock);
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// `async.await` op lowering will create resume blocks for async
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// continuations, and will conditionally branch to cleanup or suspend blocks.
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return {createToken.getResult(0), coroHdl.getResult(0), cleanupBlock,
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suspendBlock};
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}
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// Adds a suspension point before the `op`, and moves `op` and all operations
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// after it into the resume block. Returns a pointer to the resume block.
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//
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// `coroState` must be a value returned from the call to @llvm.coro.save(...)
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// intrinsic (saved coroutine state).
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//
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// Before:
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//
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// ^bb0:
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// "opBefore"(...)
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// "op"(...)
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// ^cleanup: ...
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// ^suspend: ...
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//
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// After:
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//
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// ^bb0:
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// "opBefore"(...)
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// %suspend = llmv.call @llvm.coro.suspend(...)
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// switch %suspend [-1: ^suspend, 0: ^resume, 1: ^cleanup]
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// ^resume:
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// "op"(...)
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// ^cleanup: ...
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// ^suspend: ...
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//
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static Block *addSuspensionPoint(CoroMachinery coro, Value coroState,
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Operation *op) {
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MLIRContext *ctx = op->getContext();
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auto i1 = LLVM::LLVMType::getInt1Ty(ctx);
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auto i8 = LLVM::LLVMType::getInt8Ty(ctx);
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Location loc = op->getLoc();
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Block *splitBlock = op->getBlock();
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// Split the block before `op`, newly added block is the resume block.
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Block *resume = splitBlock->splitBlock(op);
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// Add a coroutine suspension in place of original `op` in the split block.
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OpBuilder builder = OpBuilder::atBlockEnd(splitBlock);
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auto constFalse =
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builder.create<LLVM::ConstantOp>(loc, i1, builder.getBoolAttr(false));
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// Suspend a coroutine: @llvm.coro.suspend
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auto coroSuspend = builder.create<LLVM::CallOp>(
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loc, i8, builder.getSymbolRefAttr(kCoroSuspend),
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ValueRange({coroState, constFalse}));
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// After a suspension point decide if we should branch into resume, cleanup
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// or suspend block of the coroutine (see @llvm.coro.suspend return code
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// documentation).
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auto constZero =
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builder.create<LLVM::ConstantOp>(loc, i8, builder.getI8IntegerAttr(0));
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auto constNegOne =
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builder.create<LLVM::ConstantOp>(loc, i8, builder.getI8IntegerAttr(-1));
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Block *resumeOrCleanup = builder.createBlock(resume);
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// Suspend the coroutine ...?
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builder.setInsertionPointToEnd(splitBlock);
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auto isNegOne = builder.create<LLVM::ICmpOp>(
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loc, LLVM::ICmpPredicate::eq, coroSuspend.getResult(0), constNegOne);
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builder.create<LLVM::CondBrOp>(loc, isNegOne, /*trueDest=*/coro.suspend,
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/*falseDest=*/resumeOrCleanup);
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// ... or resume or cleanup the coroutine?
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builder.setInsertionPointToStart(resumeOrCleanup);
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auto isZero = builder.create<LLVM::ICmpOp>(
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loc, LLVM::ICmpPredicate::eq, coroSuspend.getResult(0), constZero);
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builder.create<LLVM::CondBrOp>(loc, isZero, /*trueDest=*/resume,
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/*falseDest=*/coro.cleanup);
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return resume;
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}
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// Outline the body region attached to the `async.execute` op into a standalone
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// function.
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static std::pair<FuncOp, CoroMachinery>
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outlineExecuteOp(SymbolTable &symbolTable, ExecuteOp execute) {
|
|
ModuleOp module = execute.getParentOfType<ModuleOp>();
|
|
|
|
MLIRContext *ctx = module.getContext();
|
|
Location loc = execute.getLoc();
|
|
|
|
OpBuilder moduleBuilder(module.getBody()->getTerminator());
|
|
|
|
// Get values captured by the async region
|
|
llvm::SetVector<mlir::Value> usedAbove;
|
|
getUsedValuesDefinedAbove(execute.body(), usedAbove);
|
|
|
|
// Collect types of the captured values.
|
|
auto usedAboveTypes =
|
|
llvm::map_range(usedAbove, [](Value value) { return value.getType(); });
|
|
SmallVector<Type, 4> inputTypes(usedAboveTypes.begin(), usedAboveTypes.end());
|
|
auto outputTypes = execute.getResultTypes();
|
|
|
|
auto funcType = moduleBuilder.getFunctionType(inputTypes, outputTypes);
|
|
auto funcAttrs = ArrayRef<NamedAttribute>();
|
|
|
|
// TODO: Derive outlined function name from the parent FuncOp (support
|
|
// multiple nested async.execute operations).
|
|
FuncOp func = FuncOp::create(loc, kAsyncFnPrefix, funcType, funcAttrs);
|
|
symbolTable.insert(func, moduleBuilder.getInsertionPoint());
|
|
|
|
SymbolTable::setSymbolVisibility(func, SymbolTable::Visibility::Private);
|
|
|
|
// Prepare a function for coroutine lowering by adding entry/cleanup/suspend
|
|
// blocks, adding llvm.coro instrinsics and setting up control flow.
|
|
CoroMachinery coro = setupCoroMachinery(func);
|
|
|
|
// Suspend async function at the end of an entry block, and resume it using
|
|
// Async execute API (execution will be resumed in a thread managed by the
|
|
// async runtime).
|
|
Block *entryBlock = &func.getBlocks().front();
|
|
OpBuilder builder = OpBuilder::atBlockTerminator(entryBlock);
|
|
|
|
// A pointer to coroutine resume intrinsic wrapper.
|
|
auto resumeFnTy = AsyncAPI::resumeFunctionType(ctx);
|
|
auto resumePtr = builder.create<LLVM::AddressOfOp>(
|
|
loc, resumeFnTy.getPointerTo(), kResume);
|
|
|
|
// Save the coroutine state: @llvm.coro.save
|
|
auto coroSave = builder.create<LLVM::CallOp>(
|
|
loc, LLVM::LLVMTokenType::get(ctx), builder.getSymbolRefAttr(kCoroSave),
|
|
ValueRange({coro.coroHandle}));
|
|
|
|
// Call async runtime API to execute a coroutine in the managed thread.
|
|
SmallVector<Value, 2> executeArgs = {coro.coroHandle, resumePtr.res()};
|
|
builder.create<CallOp>(loc, Type(), kExecute, executeArgs);
|
|
|
|
// Split the entry block before the terminator.
|
|
Block *resume = addSuspensionPoint(coro, coroSave.getResult(0),
|
|
entryBlock->getTerminator());
|
|
|
|
// Map from values defined above the execute op to the function arguments.
|
|
BlockAndValueMapping valueMapping;
|
|
valueMapping.map(usedAbove, func.getArguments());
|
|
|
|
// Clone all operations from the execute operation body into the outlined
|
|
// function body, and replace all `async.yield` operations with a call
|
|
// to async runtime to emplace the result token.
|
|
builder.setInsertionPointToStart(resume);
|
|
for (Operation &op : execute.body().getOps()) {
|
|
if (isa<async::YieldOp>(op)) {
|
|
builder.create<CallOp>(loc, kEmplaceToken, Type(), coro.asyncToken);
|
|
continue;
|
|
}
|
|
builder.clone(op, valueMapping);
|
|
}
|
|
|
|
// Replace the original `async.execute` with a call to outlined function.
|
|
OpBuilder callBuilder(execute);
|
|
SmallVector<Value, 4> usedAboveArgs(usedAbove.begin(), usedAbove.end());
|
|
auto callOutlinedFunc = callBuilder.create<CallOp>(
|
|
loc, func.getName(), execute.getResultTypes(), usedAboveArgs);
|
|
execute.replaceAllUsesWith(callOutlinedFunc.getResults());
|
|
execute.erase();
|
|
|
|
return {func, coro};
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Convert Async dialect types to LLVM types.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
class AsyncRuntimeTypeConverter : public TypeConverter {
|
|
public:
|
|
AsyncRuntimeTypeConverter() { addConversion(convertType); }
|
|
|
|
static Type convertType(Type type) {
|
|
MLIRContext *ctx = type.getContext();
|
|
// Convert async tokens to opaque pointers.
|
|
if (type.isa<TokenType>())
|
|
return LLVM::LLVMType::getInt8PtrTy(ctx);
|
|
return type;
|
|
}
|
|
};
|
|
} // namespace
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Convert types for all call operations to lowered async types.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
class CallOpOpConversion : public ConversionPattern {
|
|
public:
|
|
explicit CallOpOpConversion(MLIRContext *ctx)
|
|
: ConversionPattern(CallOp::getOperationName(), 1, ctx) {}
|
|
|
|
LogicalResult
|
|
matchAndRewrite(Operation *op, ArrayRef<Value> operands,
|
|
ConversionPatternRewriter &rewriter) const override {
|
|
AsyncRuntimeTypeConverter converter;
|
|
|
|
SmallVector<Type, 5> resultTypes;
|
|
converter.convertTypes(op->getResultTypes(), resultTypes);
|
|
|
|
CallOp call = cast<CallOp>(op);
|
|
rewriter.replaceOpWithNewOp<CallOp>(op, resultTypes, call.callee(),
|
|
call.getOperands());
|
|
|
|
return success();
|
|
}
|
|
};
|
|
} // namespace
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// async.await op lowering to mlirAsyncRuntimeAwaitToken function call.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
class AwaitOpLowering : public ConversionPattern {
|
|
public:
|
|
explicit AwaitOpLowering(
|
|
MLIRContext *ctx,
|
|
const llvm::DenseMap<FuncOp, CoroMachinery> &outlinedFunctions)
|
|
: ConversionPattern(AwaitOp::getOperationName(), 1, ctx),
|
|
outlinedFunctions(outlinedFunctions) {}
|
|
|
|
LogicalResult
|
|
matchAndRewrite(Operation *op, ArrayRef<Value> operands,
|
|
ConversionPatternRewriter &rewriter) const override {
|
|
// We can only await on the token operand. Async valus are not supported.
|
|
auto await = cast<AwaitOp>(op);
|
|
if (!await.operand().getType().isa<TokenType>())
|
|
return failure();
|
|
|
|
// Check if `async.await` is inside the outlined coroutine function.
|
|
auto func = await.getParentOfType<FuncOp>();
|
|
auto outlined = outlinedFunctions.find(func);
|
|
const bool isInCoroutine = outlined != outlinedFunctions.end();
|
|
|
|
Location loc = op->getLoc();
|
|
|
|
// Inside regular function we convert await operation to the blocking
|
|
// async API await function call.
|
|
if (!isInCoroutine)
|
|
rewriter.create<CallOp>(loc, Type(), kAwaitToken,
|
|
ValueRange(op->getOperand(0)));
|
|
|
|
// Inside the coroutine we convert await operation into coroutine suspension
|
|
// point, and resume execution asynchronously.
|
|
if (isInCoroutine) {
|
|
const CoroMachinery &coro = outlined->getSecond();
|
|
|
|
OpBuilder builder(op);
|
|
MLIRContext *ctx = op->getContext();
|
|
|
|
// A pointer to coroutine resume intrinsic wrapper.
|
|
auto resumeFnTy = AsyncAPI::resumeFunctionType(ctx);
|
|
auto resumePtr = builder.create<LLVM::AddressOfOp>(
|
|
loc, resumeFnTy.getPointerTo(), kResume);
|
|
|
|
// Save the coroutine state: @llvm.coro.save
|
|
auto coroSave = builder.create<LLVM::CallOp>(
|
|
loc, LLVM::LLVMTokenType::get(ctx),
|
|
builder.getSymbolRefAttr(kCoroSave), ValueRange(coro.coroHandle));
|
|
|
|
// Call async runtime API to resume a coroutine in the managed thread when
|
|
// the async await argument becomes ready.
|
|
SmallVector<Value, 3> awaitAndExecuteArgs = {
|
|
await.getOperand(), coro.coroHandle, resumePtr.res()};
|
|
builder.create<CallOp>(loc, Type(), kAwaitAndExecute,
|
|
awaitAndExecuteArgs);
|
|
|
|
// Split the entry block before the await operation.
|
|
addSuspensionPoint(coro, coroSave.getResult(0), op);
|
|
}
|
|
|
|
// Original operation was replaced by function call or suspension point.
|
|
rewriter.eraseOp(op);
|
|
|
|
return success();
|
|
}
|
|
|
|
private:
|
|
const llvm::DenseMap<FuncOp, CoroMachinery> &outlinedFunctions;
|
|
};
|
|
} // namespace
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
struct ConvertAsyncToLLVMPass
|
|
: public ConvertAsyncToLLVMBase<ConvertAsyncToLLVMPass> {
|
|
void runOnOperation() override;
|
|
};
|
|
|
|
void ConvertAsyncToLLVMPass::runOnOperation() {
|
|
ModuleOp module = getOperation();
|
|
SymbolTable symbolTable(module);
|
|
|
|
// Outline all `async.execute` body regions into async functions (coroutines).
|
|
llvm::DenseMap<FuncOp, CoroMachinery> outlinedFunctions;
|
|
|
|
WalkResult outlineResult = module.walk([&](ExecuteOp execute) {
|
|
// We currently do not support execute operations that take async
|
|
// token dependencies, async value arguments or produce async results.
|
|
if (!execute.dependencies().empty() || !execute.operands().empty() ||
|
|
!execute.results().empty()) {
|
|
execute.emitOpError(
|
|
"Can't outline async.execute op with async dependencies, arguments "
|
|
"or returned async results");
|
|
return WalkResult::interrupt();
|
|
}
|
|
|
|
outlinedFunctions.insert(outlineExecuteOp(symbolTable, execute));
|
|
|
|
return WalkResult::advance();
|
|
});
|
|
|
|
// Failed to outline all async execute operations.
|
|
if (outlineResult.wasInterrupted()) {
|
|
signalPassFailure();
|
|
return;
|
|
}
|
|
|
|
LLVM_DEBUG({
|
|
llvm::dbgs() << "Outlined " << outlinedFunctions.size()
|
|
<< " async functions\n";
|
|
});
|
|
|
|
// Add declarations for all functions required by the coroutines lowering.
|
|
addResumeFunction(module);
|
|
addAsyncRuntimeApiDeclarations(module);
|
|
addCoroutineIntrinsicsDeclarations(module);
|
|
addCRuntimeDeclarations(module);
|
|
|
|
MLIRContext *ctx = &getContext();
|
|
|
|
// Convert async dialect types and operations to LLVM dialect.
|
|
AsyncRuntimeTypeConverter converter;
|
|
OwningRewritePatternList patterns;
|
|
|
|
populateFuncOpTypeConversionPattern(patterns, ctx, converter);
|
|
patterns.insert<CallOpOpConversion>(ctx);
|
|
patterns.insert<AwaitOpLowering>(ctx, outlinedFunctions);
|
|
|
|
ConversionTarget target(*ctx);
|
|
target.addLegalDialect<LLVM::LLVMDialect>();
|
|
target.addIllegalDialect<AsyncDialect>();
|
|
target.addDynamicallyLegalOp<FuncOp>(
|
|
[&](FuncOp op) { return converter.isSignatureLegal(op.getType()); });
|
|
target.addDynamicallyLegalOp<CallOp>(
|
|
[&](CallOp op) { return converter.isLegal(op.getResultTypes()); });
|
|
|
|
if (failed(applyPartialConversion(module, target, patterns)))
|
|
signalPassFailure();
|
|
}
|
|
} // namespace
|
|
|
|
std::unique_ptr<OperationPass<ModuleOp>> mlir::createConvertAsyncToLLVMPass() {
|
|
return std::make_unique<ConvertAsyncToLLVMPass>();
|
|
}
|