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[Coroutines] Move Shape to its own header
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* Plugin libraries to create custom ABIs will need access to CoroShape.
* As a step in enabling plugin libraries, move Shape into its own header
  that will eventually be moved into include/llvm/Transforms/Coroutines
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tnowicki committed Sep 12, 2024
1 parent 2670565 commit fd2bd5c
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Showing 4 changed files with 252 additions and 223 deletions.
1 change: 1 addition & 0 deletions llvm/lib/Transforms/Coroutines/CoroEarly.cpp
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#include "llvm/Transforms/Coroutines/CoroEarly.h"
#include "CoroInternal.h"
#include "CoroShape.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
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224 changes: 1 addition & 223 deletions llvm/lib/Transforms/Coroutines/CoroInternal.h
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#define LLVM_LIB_TRANSFORMS_COROUTINES_COROINTERNAL_H

#include "CoroInstr.h"
#include "CoroShape.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/IRBuilder.h"

Expand Down Expand Up @@ -58,229 +59,6 @@ struct LowererBase {
CallInst *makeSubFnCall(Value *Arg, int Index, Instruction *InsertPt);
};

enum class ABI {
/// The "resume-switch" lowering, where there are separate resume and
/// destroy functions that are shared between all suspend points. The
/// coroutine frame implicitly stores the resume and destroy functions,
/// the current index, and any promise value.
Switch,

/// The "returned-continuation" lowering, where each suspend point creates a
/// single continuation function that is used for both resuming and
/// destroying. Does not support promises.
Retcon,

/// The "unique returned-continuation" lowering, where each suspend point
/// creates a single continuation function that is used for both resuming
/// and destroying. Does not support promises. The function is known to
/// suspend at most once during its execution, and the return value of
/// the continuation is void.
RetconOnce,

/// The "async continuation" lowering, where each suspend point creates a
/// single continuation function. The continuation function is available as an
/// intrinsic.
Async,
};

// Holds structural Coroutine Intrinsics for a particular function and other
// values used during CoroSplit pass.
struct LLVM_LIBRARY_VISIBILITY Shape {
CoroBeginInst *CoroBegin;
SmallVector<AnyCoroEndInst *, 4> CoroEnds;
SmallVector<CoroSizeInst *, 2> CoroSizes;
SmallVector<CoroAlignInst *, 2> CoroAligns;
SmallVector<AnyCoroSuspendInst *, 4> CoroSuspends;
SmallVector<CallInst*, 2> SwiftErrorOps;
SmallVector<CoroAwaitSuspendInst *, 4> CoroAwaitSuspends;
SmallVector<CallInst *, 2> SymmetricTransfers;

// Field indexes for special fields in the switch lowering.
struct SwitchFieldIndex {
enum {
Resume,
Destroy

// The promise field is always at a fixed offset from the start of
// frame given its type, but the index isn't a constant for all
// possible frames.

// The switch-index field isn't at a fixed offset or index, either;
// we just work it in where it fits best.
};
};

coro::ABI ABI;

StructType *FrameTy;
Align FrameAlign;
uint64_t FrameSize;
Value *FramePtr;
BasicBlock *AllocaSpillBlock;

/// This would only be true if optimization are enabled.
bool OptimizeFrame;

struct SwitchLoweringStorage {
SwitchInst *ResumeSwitch;
AllocaInst *PromiseAlloca;
BasicBlock *ResumeEntryBlock;
unsigned IndexField;
unsigned IndexAlign;
unsigned IndexOffset;
bool HasFinalSuspend;
bool HasUnwindCoroEnd;
};

struct RetconLoweringStorage {
Function *ResumePrototype;
Function *Alloc;
Function *Dealloc;
BasicBlock *ReturnBlock;
bool IsFrameInlineInStorage;
};

struct AsyncLoweringStorage {
Value *Context;
CallingConv::ID AsyncCC;
unsigned ContextArgNo;
uint64_t ContextHeaderSize;
uint64_t ContextAlignment;
uint64_t FrameOffset; // Start of the frame.
uint64_t ContextSize; // Includes frame size.
GlobalVariable *AsyncFuncPointer;

Align getContextAlignment() const { return Align(ContextAlignment); }
};

union {
SwitchLoweringStorage SwitchLowering;
RetconLoweringStorage RetconLowering;
AsyncLoweringStorage AsyncLowering;
};

CoroIdInst *getSwitchCoroId() const {
assert(ABI == coro::ABI::Switch);
return cast<CoroIdInst>(CoroBegin->getId());
}

AnyCoroIdRetconInst *getRetconCoroId() const {
assert(ABI == coro::ABI::Retcon ||
ABI == coro::ABI::RetconOnce);
return cast<AnyCoroIdRetconInst>(CoroBegin->getId());
}

CoroIdAsyncInst *getAsyncCoroId() const {
assert(ABI == coro::ABI::Async);
return cast<CoroIdAsyncInst>(CoroBegin->getId());
}

unsigned getSwitchIndexField() const {
assert(ABI == coro::ABI::Switch);
assert(FrameTy && "frame type not assigned");
return SwitchLowering.IndexField;
}
IntegerType *getIndexType() const {
assert(ABI == coro::ABI::Switch);
assert(FrameTy && "frame type not assigned");
return cast<IntegerType>(FrameTy->getElementType(getSwitchIndexField()));
}
ConstantInt *getIndex(uint64_t Value) const {
return ConstantInt::get(getIndexType(), Value);
}

PointerType *getSwitchResumePointerType() const {
assert(ABI == coro::ABI::Switch);
assert(FrameTy && "frame type not assigned");
return cast<PointerType>(FrameTy->getElementType(SwitchFieldIndex::Resume));
}

FunctionType *getResumeFunctionType() const {
switch (ABI) {
case coro::ABI::Switch:
return FunctionType::get(Type::getVoidTy(FrameTy->getContext()),
PointerType::getUnqual(FrameTy->getContext()),
/*IsVarArg=*/false);
case coro::ABI::Retcon:
case coro::ABI::RetconOnce:
return RetconLowering.ResumePrototype->getFunctionType();
case coro::ABI::Async:
// Not used. The function type depends on the active suspend.
return nullptr;
}

llvm_unreachable("Unknown coro::ABI enum");
}

ArrayRef<Type*> getRetconResultTypes() const {
assert(ABI == coro::ABI::Retcon ||
ABI == coro::ABI::RetconOnce);
auto FTy = CoroBegin->getFunction()->getFunctionType();

// The safety of all this is checked by checkWFRetconPrototype.
if (auto STy = dyn_cast<StructType>(FTy->getReturnType())) {
return STy->elements().slice(1);
} else {
return ArrayRef<Type*>();
}
}

ArrayRef<Type*> getRetconResumeTypes() const {
assert(ABI == coro::ABI::Retcon ||
ABI == coro::ABI::RetconOnce);

// The safety of all this is checked by checkWFRetconPrototype.
auto FTy = RetconLowering.ResumePrototype->getFunctionType();
return FTy->params().slice(1);
}

CallingConv::ID getResumeFunctionCC() const {
switch (ABI) {
case coro::ABI::Switch:
return CallingConv::Fast;

case coro::ABI::Retcon:
case coro::ABI::RetconOnce:
return RetconLowering.ResumePrototype->getCallingConv();
case coro::ABI::Async:
return AsyncLowering.AsyncCC;
}
llvm_unreachable("Unknown coro::ABI enum");
}

AllocaInst *getPromiseAlloca() const {
if (ABI == coro::ABI::Switch)
return SwitchLowering.PromiseAlloca;
return nullptr;
}

BasicBlock::iterator getInsertPtAfterFramePtr() const {
if (auto *I = dyn_cast<Instruction>(FramePtr)) {
BasicBlock::iterator It = std::next(I->getIterator());
It.setHeadBit(true); // Copy pre-RemoveDIs behaviour.
return It;
}
return cast<Argument>(FramePtr)->getParent()->getEntryBlock().begin();
}

/// Allocate memory according to the rules of the active lowering.
///
/// \param CG - if non-null, will be updated for the new call
Value *emitAlloc(IRBuilder<> &Builder, Value *Size, CallGraph *CG) const;

/// Deallocate memory according to the rules of the active lowering.
///
/// \param CG - if non-null, will be updated for the new call
void emitDealloc(IRBuilder<> &Builder, Value *Ptr, CallGraph *CG) const;

Shape() = default;
explicit Shape(Function &F, bool OptimizeFrame = false)
: OptimizeFrame(OptimizeFrame) {
buildFrom(F);
}
void buildFrom(Function &F);
};

bool defaultMaterializable(Instruction &V);
void normalizeCoroutine(Function &F, coro::Shape &Shape,
TargetTransformInfo &TTI);
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