llvm/llvm/include/llvm/Transforms/Coroutines/SuspendCrossingInfo.h

//===- SuspendCrossingInfo.cpp - Utility for suspend crossing values ------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// The SuspendCrossingInfo maintains data that allows to answer a question
// whether given two BasicBlocks A and B there is a path from A to B that
// passes through a suspend point. Note, SuspendCrossingInfo is invalidated
// by changes to the CFG including adding/removing BBs due to its use of BB
// ptrs in the BlockToIndexMapping.
//===----------------------------------------------------------------------===//

#ifndef LLVM_TRANSFORMS_COROUTINES_SUSPENDCROSSINGINFO_H
#define LLVM_TRANSFORMS_COROUTINES_SUSPENDCROSSINGINFO_H

#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instruction.h"
#include "llvm/Transforms/Coroutines/CoroInstr.h"

namespace llvm {

// Provides two way mapping between the blocks and numbers.
class BlockToIndexMapping { … };

// The SuspendCrossingInfo maintains data that allows to answer a question
// whether given two BasicBlocks A and B there is a path from A to B that
// passes through a suspend point.
//
// For every basic block 'i' it maintains a BlockData that consists of:
//   Consumes:  a bit vector which contains a set of indices of blocks that can
//              reach block 'i'. A block can trivially reach itself.
//   Kills: a bit vector which contains a set of indices of blocks that can
//          reach block 'i' but there is a path crossing a suspend point
//          not repeating 'i' (path to 'i' without cycles containing 'i').
//   Suspend: a boolean indicating whether block 'i' contains a suspend point.
//   End: a boolean indicating whether block 'i' contains a coro.end intrinsic.
//   KillLoop: There is a path from 'i' to 'i' not otherwise repeating 'i' that
//             crosses a suspend point.
//
class SuspendCrossingInfo { … };

} // namespace llvm

#endif // LLVM_TRANSFORMS_COROUTINES_SUSPENDCROSSINGINFO_H