llvm/llvm/tools/llvm-profgen/CSPreInliner.cpp

//===-- CSPreInliner.cpp - Profile guided preinliner -------------- 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
//
//===----------------------------------------------------------------------===//

#include "CSPreInliner.h"
#include "ProfiledBinary.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/DebugInfo/Symbolize/SymbolizableModule.h"
#include "llvm/Transforms/IPO/SampleProfile.h"
#include <cstdint>
#include <queue>

#define DEBUG_TYPE …

usingnamespacellvm;
usingnamespacesampleprof;

STATISTIC(PreInlNumCSInlined,
          "Number of functions inlined with context sensitive profile");
STATISTIC(PreInlNumCSNotInlined,
          "Number of functions not inlined with context sensitive profile");
STATISTIC(PreInlNumCSInlinedHitMinLimit,
          "Number of functions with FDO inline stopped due to min size limit");
STATISTIC(PreInlNumCSInlinedHitMaxLimit,
          "Number of functions with FDO inline stopped due to max size limit");
STATISTIC(
    PreInlNumCSInlinedHitGrowthLimit,
    "Number of functions with FDO inline stopped due to growth size limit");

// The switches specify inline thresholds used in SampleProfileLoader inlining.
// TODO: the actual threshold to be tuned here because the size here is based
// on machine code not LLVM IR.
namespace llvm {
cl::opt<bool> EnableCSPreInliner(
    "csspgo-preinliner", cl::Hidden, cl::init(true),
    cl::desc("Run a global pre-inliner to merge context profile based on "
             "estimated global top-down inline decisions"));

cl::opt<bool> UseContextCostForPreInliner(
    "use-context-cost-for-preinliner", cl::Hidden, cl::init(true),
    cl::desc("Use context-sensitive byte size cost for preinliner decisions"));
} // namespace llvm

static cl::opt<bool> SamplePreInlineReplay(
    "csspgo-replay-preinline", cl::Hidden, cl::init(false),
    cl::desc(
        "Replay previous inlining and adjust context profile accordingly"));

static cl::opt<int> CSPreinlMultiplierForPrevInl(
    "csspgo-preinliner-multiplier-for-previous-inlining", cl::Hidden,
    cl::init(100),
    cl::desc(
        "Multiplier to bump up callsite threshold for previous inlining."));

CSPreInliner::CSPreInliner(SampleContextTracker &Tracker,
                           ProfiledBinary &Binary, ProfileSummary *Summary)
    : … { … }

std::vector<FunctionId> CSPreInliner::buildTopDownOrder() { … }

bool CSPreInliner::getInlineCandidates(ProfiledCandidateQueue &CQueue,
                                       const FunctionSamples *CallerSamples) { … }

uint32_t CSPreInliner::getFuncSize(const ContextTrieNode *ContextNode) { … }

bool CSPreInliner::shouldInline(ProfiledInlineCandidate &Candidate) { … }

void CSPreInliner::processFunction(const FunctionId Name) { … }

void CSPreInliner::run() { … }