llvm/llvm/include/llvm/ProfileData/PGOCtxProfReader.h

//===--- PGOCtxProfReader.h - Contextual profile reader ---------*- C++ -*-===//
//
// 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
///
/// Reader for contextual iFDO profile, which comes in bitstream format.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_PROFILEDATA_CTXINSTRPROFILEREADER_H
#define LLVM_PROFILEDATA_CTXINSTRPROFILEREADER_H

#include "llvm/Bitstream/BitstreamReader.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/ProfileData/PGOCtxProfWriter.h"
#include "llvm/Support/Error.h"
#include <map>

namespace llvm {
class PGOContextualProfile;
class PGOCtxProfContext;

namespace internal {
// When we traverse the contextual profile, we typically want to visit contexts
// pertaining to a specific function. To avoid traversing the whole tree, we
// want to keep a per-function list - which will be in preorder - of that
// function's contexts. This happens in PGOContextualProfile. For memory use
// efficiency, we want to make PGOCtxProfContext an intrusive double-linked list
// node. We need to handle the cases where PGOCtxProfContext nodes are moved and
// deleted: in both cases, we need to update the index (==list). We can do that
// directly from the node in the list, without knowing who the "parent" of the
// list is. That makes the ADT ilist overkill here. Finally, IndexNode is meant
// to be an implementation detail of PGOCtxProfContext, and the only reason it's
// factored out is to avoid implementing move semantics for all its members.
class IndexNode { … };
} // namespace internal

/// A node (context) in the loaded contextual profile, suitable for mutation
/// during IPO passes. We generally expect a fraction of counters and
/// callsites to be populated. We continue to model counters as vectors, but
/// callsites are modeled as a map of a map. The expectation is that, typically,
/// there is a small number of indirect targets (usually, 1 for direct calls);
/// but potentially a large number of callsites, and, as inlining progresses,
/// the callsite count of a caller will grow.
class PGOCtxProfContext final : public internal::IndexNode { … };

class PGOCtxProfileReader final { … };
} // namespace llvm
#endif