mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-22 10:42:39 +01:00
89 lines
3.2 KiB
C++
89 lines
3.2 KiB
C++
//==-SummaryBasedOptimizations.cpp - Optimizations based on ThinLTO summary-==//
|
|
//
|
|
// 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements optimizations that are based on the module summaries.
|
|
// These optimizations are performed during the thinlink phase of the
|
|
// compilation.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/LTO/SummaryBasedOptimizations.h"
|
|
#include "llvm/Analysis/SyntheticCountsUtils.h"
|
|
#include "llvm/IR/ModuleSummaryIndex.h"
|
|
#include "llvm/Support/CommandLine.h"
|
|
|
|
using namespace llvm;
|
|
|
|
static cl::opt<bool> ThinLTOSynthesizeEntryCounts(
|
|
"thinlto-synthesize-entry-counts", cl::init(false), cl::Hidden,
|
|
cl::desc("Synthesize entry counts based on the summary"));
|
|
|
|
namespace llvm {
|
|
extern cl::opt<int> InitialSyntheticCount;
|
|
}
|
|
|
|
static void initializeCounts(ModuleSummaryIndex &Index) {
|
|
auto Root = Index.calculateCallGraphRoot();
|
|
// Root is a fake node. All its successors are the actual roots of the
|
|
// callgraph.
|
|
// FIXME: This initializes the entry counts of only the root nodes. This makes
|
|
// sense when compiling a binary with ThinLTO, but for libraries any of the
|
|
// non-root nodes could be called from outside.
|
|
for (auto &C : Root.calls()) {
|
|
auto &V = C.first;
|
|
for (auto &GVS : V.getSummaryList()) {
|
|
auto S = GVS.get()->getBaseObject();
|
|
auto *F = cast<FunctionSummary>(S);
|
|
F->setEntryCount(InitialSyntheticCount);
|
|
}
|
|
}
|
|
}
|
|
|
|
void llvm::computeSyntheticCounts(ModuleSummaryIndex &Index) {
|
|
if (!ThinLTOSynthesizeEntryCounts)
|
|
return;
|
|
|
|
using Scaled64 = ScaledNumber<uint64_t>;
|
|
initializeCounts(Index);
|
|
auto GetCallSiteRelFreq = [](FunctionSummary::EdgeTy &Edge) {
|
|
return Scaled64(Edge.second.RelBlockFreq, -CalleeInfo::ScaleShift);
|
|
};
|
|
auto GetEntryCount = [](ValueInfo V) {
|
|
if (V.getSummaryList().size()) {
|
|
auto S = V.getSummaryList().front().get()->getBaseObject();
|
|
auto *F = cast<FunctionSummary>(S);
|
|
return F->entryCount();
|
|
} else {
|
|
return UINT64_C(0);
|
|
}
|
|
};
|
|
auto AddToEntryCount = [](ValueInfo V, Scaled64 New) {
|
|
if (!V.getSummaryList().size())
|
|
return;
|
|
for (auto &GVS : V.getSummaryList()) {
|
|
auto S = GVS.get()->getBaseObject();
|
|
auto *F = cast<FunctionSummary>(S);
|
|
F->setEntryCount(
|
|
SaturatingAdd(F->entryCount(), New.template toInt<uint64_t>()));
|
|
}
|
|
};
|
|
|
|
auto GetProfileCount = [&](ValueInfo V, FunctionSummary::EdgeTy &Edge) {
|
|
auto RelFreq = GetCallSiteRelFreq(Edge);
|
|
Scaled64 EC(GetEntryCount(V), 0);
|
|
return RelFreq * EC;
|
|
};
|
|
// After initializing the counts in initializeCounts above, the counts have to
|
|
// be propagated across the combined callgraph.
|
|
// SyntheticCountsUtils::propagate takes care of this propagation on any
|
|
// callgraph that specialized GraphTraits.
|
|
SyntheticCountsUtils<ModuleSummaryIndex *>::propagate(&Index, GetProfileCount,
|
|
AddToEntryCount);
|
|
Index.setHasSyntheticEntryCounts();
|
|
}
|