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6795b93241
Summary: This patch adds simple coroutine splitting logic to CoroSplit pass. Documentation and overview is here: http://llvm.org/docs/Coroutines.html. Upstreaming sequence (rough plan) 1.Add documentation. (https://reviews.llvm.org/D22603) 2.Add coroutine intrinsics. (https://reviews.llvm.org/D22659) ... 7. Split coroutine into subfunctions <= we are here 8. Coroutine Frame Building algorithm 9. Handle coroutine with unwinds 10+. The rest of the logic Reviewers: majnemer Subscribers: llvm-commits, mehdi_amini Differential Revision: https://reviews.llvm.org/D23461 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278830 91177308-0d34-0410-b5e6-96231b3b80d8
105 lines
3.5 KiB
C++
105 lines
3.5 KiB
C++
//===- CoroFrame.cpp - Builds and manipulates coroutine frame -------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// This file contains classes used to discover if for a particular value
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// there from sue to definition that crosses a suspend block.
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//
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// Using the information discovered we form a Coroutine Frame structure to
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// contain those values. All uses of those values are replaced with appropriate
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// GEP + load from the coroutine frame. At the point of the definition we spill
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// the value into the coroutine frame.
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//
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// TODO: pack values tightly using liveness info.
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//===----------------------------------------------------------------------===//
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#include "CoroInternal.h"
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#include "llvm/IR/IRBuilder.h"
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using namespace llvm;
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// TODO: Implement in future patches.
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struct SpillInfo {};
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// Build a struct that will keep state for an active coroutine.
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// struct f.frame {
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// ResumeFnTy ResumeFnAddr;
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// ResumeFnTy DestroyFnAddr;
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// int ResumeIndex;
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// ... promise (if present) ...
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// ... spills ...
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// };
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static StructType *buildFrameType(Function &F, coro::Shape &Shape,
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SpillInfo &Spills) {
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LLVMContext &C = F.getContext();
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SmallString<32> Name(F.getName());
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Name.append(".Frame");
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StructType *FrameTy = StructType::create(C, Name);
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auto *FramePtrTy = FrameTy->getPointerTo();
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auto *FnTy = FunctionType::get(Type::getVoidTy(C), FramePtrTy,
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/*IsVarArgs=*/false);
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auto *FnPtrTy = FnTy->getPointerTo();
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if (Shape.CoroSuspends.size() > UINT32_MAX)
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report_fatal_error("Cannot handle coroutine with this many suspend points");
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SmallVector<Type *, 8> Types{FnPtrTy, FnPtrTy, Type::getInt32Ty(C)};
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// TODO: Populate from Spills.
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FrameTy->setBody(Types);
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return FrameTy;
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}
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// Replace all alloca and SSA values that are accessed across suspend points
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// with GetElementPointer from coroutine frame + loads and stores. Create an
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// AllocaSpillBB that will become the new entry block for the resume parts of
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// the coroutine:
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//
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// %hdl = coro.begin(...)
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// whatever
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//
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// becomes:
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//
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// %hdl = coro.begin(...)
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// %FramePtr = bitcast i8* hdl to %f.frame*
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// br label %AllocaSpillBB
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//
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// AllocaSpillBB:
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// ; geps corresponding to allocas that were moved to coroutine frame
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// br label PostSpill
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//
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// PostSpill:
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// whatever
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//
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//
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static Instruction *insertSpills(SpillInfo &Spills, coro::Shape &Shape) {
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auto *CB = Shape.CoroBegin;
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IRBuilder<> Builder(CB->getNextNode());
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PointerType *FramePtrTy = Shape.FrameTy->getPointerTo();
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auto *FramePtr =
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cast<Instruction>(Builder.CreateBitCast(CB, FramePtrTy, "FramePtr"));
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// TODO: Insert Spills.
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auto *FramePtrBB = FramePtr->getParent();
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Shape.AllocaSpillBlock =
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FramePtrBB->splitBasicBlock(FramePtr->getNextNode(), "AllocaSpillBB");
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Shape.AllocaSpillBlock->splitBasicBlock(&Shape.AllocaSpillBlock->front(),
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"PostSpill");
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// TODO: Insert geps for alloca moved to coroutine frame.
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return FramePtr;
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}
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void coro::buildCoroutineFrame(Function &F, Shape &Shape) {
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SpillInfo Spills;
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// TODO: Compute Spills (incoming in later patches).
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Shape.FrameTy = buildFrameType(F, Shape, Spills);
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Shape.FramePtr = insertSpills(Spills, Shape);
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}
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