================ @@ -0,0 +1,147 @@ +//===- CoroAnnotationElide.cpp - Elide attributed safe coroutine calls ----===// +// +// 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 +// +//===----------------------------------------------------------------------===// +// +// \file +// This pass transforms all Call or Invoke instructions that are annotated +// "coro_elide_safe" to call the `.noalloc` variant of coroutine instead. +// The frame of the callee coroutine is allocated inside the caller. A pointer +// to the allocated frame will be passed into the `.noalloc` ramp function. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Transforms/Coroutines/CoroAnnotationElide.h" + +#include "llvm/Analysis/LazyCallGraph.h" +#include "llvm/Analysis/OptimizationRemarkEmitter.h" +#include "llvm/IR/Analysis.h" +#include "llvm/IR/IRBuilder.h" +#include "llvm/IR/InstIterator.h" +#include "llvm/IR/Instruction.h" +#include "llvm/IR/Module.h" +#include "llvm/IR/PassManager.h" +#include "llvm/Transforms/Utils/CallGraphUpdater.h" + +#include <cassert> + +using namespace llvm; + +#define DEBUG_TYPE "coro-annotation-elide" + +static Instruction *getFirstNonAllocaInTheEntryBlock(Function *F) { + for (Instruction &I : F->getEntryBlock()) + if (!isa<AllocaInst>(&I)) + return &I; + llvm_unreachable("no terminator in the entry block"); +} + +// Create an alloca in the caller, using FrameSize and FrameAlign as the callee +// coroutine's activation frame. +static Value *allocateFrameInCaller(Function *Caller, uint64_t FrameSize, + Align FrameAlign) { + LLVMContext &C = Caller->getContext(); + BasicBlock::iterator InsertPt = + getFirstNonAllocaInTheEntryBlock(Caller)->getIterator(); + const DataLayout &DL = Caller->getDataLayout(); + auto FrameTy = ArrayType::get(Type::getInt8Ty(C), FrameSize); + auto *Frame = new AllocaInst(FrameTy, DL.getAllocaAddrSpace(), "", InsertPt); + Frame->setAlignment(FrameAlign); + return new BitCastInst(Frame, PointerType::getUnqual(C), "vFrame", InsertPt); +} + +// Given a call or invoke instruction to the elide safe coroutine, this function +// does the following: +// - Allocate a frame for the callee coroutine in the caller using alloca. +// - Replace the old CB with a new Call or Invoke to `NewCallee`, with the +// pointer to the frame as an additional argument to NewCallee. +static void processCall(CallBase *CB, Function *Caller, Function *NewCallee, + uint64_t FrameSize, Align FrameAlign) { + auto *FramePtr = allocateFrameInCaller(Caller, FrameSize, FrameAlign); + auto NewCBInsertPt = CB->getIterator(); + llvm::CallBase *NewCB = nullptr; + SmallVector<Value *, 4> NewArgs; + NewArgs.append(CB->arg_begin(), CB->arg_end()); + NewArgs.push_back(FramePtr); + + if (auto *CI = dyn_cast<CallInst>(CB)) { + auto *NewCI = CallInst::Create(NewCallee->getFunctionType(), NewCallee, + NewArgs, "", NewCBInsertPt); + NewCI->setTailCallKind(CI->getTailCallKind()); + NewCB = NewCI; ---------------- ChuanqiXu9 wrote:
Out of curious, why do we use a new variable here but not in the following branch? https://github.com/llvm/llvm-project/pull/99285 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
