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llvm-for-llvmta/lib/Transforms/IPO/SampleProfile.cpp

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//===- SampleProfile.cpp - Incorporate sample profiles into the IR --------===//
//
// 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 the SampleProfileLoader transformation. This pass
// reads a profile file generated by a sampling profiler (e.g. Linux Perf -
// http://perf.wiki.kernel.org/) and generates IR metadata to reflect the
// profile information in the given profile.
//
// This pass generates branch weight annotations on the IR:
//
// - prof: Represents branch weights. This annotation is added to branches
// to indicate the weights of each edge coming out of the branch.
// The weight of each edge is the weight of the target block for
// that edge. The weight of a block B is computed as the maximum
// number of samples found in B.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/SampleProfile.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/PriorityQueue.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/CallGraphSCCPass.h"
#include "llvm/Analysis/InlineAdvisor.h"
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/ReplayInlineAdvisor.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/ValueSymbolTable.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/ProfileData/SampleProf.h"
#include "llvm/ProfileData/SampleProfReader.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/GenericDomTree.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/SampleContextTracker.h"
#include "llvm/Transforms/IPO/SampleProfileProbe.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/CallPromotionUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <functional>
#include <limits>
#include <map>
#include <memory>
#include <queue>
#include <string>
#include <system_error>
#include <utility>
#include <vector>
using namespace llvm;
using namespace sampleprof;
using ProfileCount = Function::ProfileCount;
#define DEBUG_TYPE "sample-profile"
#define CSINLINE_DEBUG DEBUG_TYPE "-inline"
STATISTIC(NumCSInlined,
"Number of functions inlined with context sensitive profile");
STATISTIC(NumCSNotInlined,
"Number of functions not inlined with context sensitive profile");
STATISTIC(NumMismatchedProfile,
"Number of functions with CFG mismatched profile");
STATISTIC(NumMatchedProfile, "Number of functions with CFG matched profile");
STATISTIC(NumDuplicatedInlinesite,
"Number of inlined callsites with a partial distribution factor");
STATISTIC(NumCSInlinedHitMinLimit,
"Number of functions with FDO inline stopped due to min size limit");
STATISTIC(NumCSInlinedHitMaxLimit,
"Number of functions with FDO inline stopped due to max size limit");
STATISTIC(
NumCSInlinedHitGrowthLimit,
"Number of functions with FDO inline stopped due to growth size limit");
// Command line option to specify the file to read samples from. This is
// mainly used for debugging.
static cl::opt<std::string> SampleProfileFile(
"sample-profile-file", cl::init(""), cl::value_desc("filename"),
cl::desc("Profile file loaded by -sample-profile"), cl::Hidden);
// The named file contains a set of transformations that may have been applied
// to the symbol names between the program from which the sample data was
// collected and the current program's symbols.
static cl::opt<std::string> SampleProfileRemappingFile(
"sample-profile-remapping-file", cl::init(""), cl::value_desc("filename"),
cl::desc("Profile remapping file loaded by -sample-profile"), cl::Hidden);
static cl::opt<unsigned> SampleProfileMaxPropagateIterations(
"sample-profile-max-propagate-iterations", cl::init(100),
cl::desc("Maximum number of iterations to go through when propagating "
"sample block/edge weights through the CFG."));
static cl::opt<unsigned> SampleProfileRecordCoverage(
"sample-profile-check-record-coverage", cl::init(0), cl::value_desc("N"),
cl::desc("Emit a warning if less than N% of records in the input profile "
"are matched to the IR."));
static cl::opt<unsigned> SampleProfileSampleCoverage(
"sample-profile-check-sample-coverage", cl::init(0), cl::value_desc("N"),
cl::desc("Emit a warning if less than N% of samples in the input profile "
"are matched to the IR."));
static cl::opt<bool> NoWarnSampleUnused(
"no-warn-sample-unused", cl::init(false), cl::Hidden,
cl::desc("Use this option to turn off/on warnings about function with "
"samples but without debug information to use those samples. "));
static cl::opt<bool> ProfileSampleAccurate(
"profile-sample-accurate", cl::Hidden, cl::init(false),
cl::desc("If the sample profile is accurate, we will mark all un-sampled "
"callsite and function as having 0 samples. Otherwise, treat "
"un-sampled callsites and functions conservatively as unknown. "));
static cl::opt<bool> ProfileAccurateForSymsInList(
"profile-accurate-for-symsinlist", cl::Hidden, cl::ZeroOrMore,
cl::init(true),
cl::desc("For symbols in profile symbol list, regard their profiles to "
"be accurate. It may be overriden by profile-sample-accurate. "));
static cl::opt<bool> ProfileMergeInlinee(
"sample-profile-merge-inlinee", cl::Hidden, cl::init(true),
cl::desc("Merge past inlinee's profile to outline version if sample "
"profile loader decided not to inline a call site. It will "
"only be enabled when top-down order of profile loading is "
"enabled. "));
static cl::opt<bool> ProfileTopDownLoad(
"sample-profile-top-down-load", cl::Hidden, cl::init(true),
cl::desc("Do profile annotation and inlining for functions in top-down "
"order of call graph during sample profile loading. It only "
"works for new pass manager. "));
static cl::opt<bool> UseProfileIndirectCallEdges(
"use-profile-indirect-call-edges", cl::init(true), cl::Hidden,
cl::desc("Considering indirect call samples from profile when top-down "
"processing functions. Only CSSPGO is supported."));
static cl::opt<bool> UseProfileTopDownOrder(
"use-profile-top-down-order", cl::init(false), cl::Hidden,
cl::desc("Process functions in one SCC in a top-down order "
"based on the input profile."));
static cl::opt<bool> ProfileSizeInline(
"sample-profile-inline-size", cl::Hidden, cl::init(false),
cl::desc("Inline cold call sites in profile loader if it's beneficial "
"for code size."));
static cl::opt<int> ProfileInlineGrowthLimit(
"sample-profile-inline-growth-limit", cl::Hidden, cl::init(12),
cl::desc("The size growth ratio limit for proirity-based sample profile "
"loader inlining."));
static cl::opt<int> ProfileInlineLimitMin(
"sample-profile-inline-limit-min", cl::Hidden, cl::init(100),
cl::desc("The lower bound of size growth limit for "
"proirity-based sample profile loader inlining."));
static cl::opt<int> ProfileInlineLimitMax(
"sample-profile-inline-limit-max", cl::Hidden, cl::init(10000),
cl::desc("The upper bound of size growth limit for "
"proirity-based sample profile loader inlining."));
static cl::opt<int> ProfileICPThreshold(
"sample-profile-icp-threshold", cl::Hidden, cl::init(5),
cl::desc(
"Relative hotness threshold for indirect "
"call promotion in proirity-based sample profile loader inlining."));
static cl::opt<int> SampleHotCallSiteThreshold(
"sample-profile-hot-inline-threshold", cl::Hidden, cl::init(3000),
cl::desc("Hot callsite threshold for proirity-based sample profile loader "
"inlining."));
static cl::opt<bool> CallsitePrioritizedInline(
"sample-profile-prioritized-inline", cl::Hidden, cl::ZeroOrMore,
cl::init(false),
cl::desc("Use call site prioritized inlining for sample profile loader."
"Currently only CSSPGO is supported."));
static cl::opt<int> SampleColdCallSiteThreshold(
"sample-profile-cold-inline-threshold", cl::Hidden, cl::init(45),
cl::desc("Threshold for inlining cold callsites"));
static cl::opt<std::string> ProfileInlineReplayFile(
"sample-profile-inline-replay", cl::init(""), cl::value_desc("filename"),
cl::desc(
"Optimization remarks file containing inline remarks to be replayed "
"by inlining from sample profile loader."),
cl::Hidden);
namespace {
using BlockWeightMap = DenseMap<const BasicBlock *, uint64_t>;
using EquivalenceClassMap = DenseMap<const BasicBlock *, const BasicBlock *>;
using Edge = std::pair<const BasicBlock *, const BasicBlock *>;
using EdgeWeightMap = DenseMap<Edge, uint64_t>;
using BlockEdgeMap =
DenseMap<const BasicBlock *, SmallVector<const BasicBlock *, 8>>;
class SampleProfileLoader;
class SampleCoverageTracker {
public:
SampleCoverageTracker(SampleProfileLoader &SPL) : SPLoader(SPL){};
bool markSamplesUsed(const FunctionSamples *FS, uint32_t LineOffset,
uint32_t Discriminator, uint64_t Samples);
unsigned computeCoverage(unsigned Used, unsigned Total) const;
unsigned countUsedRecords(const FunctionSamples *FS,
ProfileSummaryInfo *PSI) const;
unsigned countBodyRecords(const FunctionSamples *FS,
ProfileSummaryInfo *PSI) const;
uint64_t getTotalUsedSamples() const { return TotalUsedSamples; }
uint64_t countBodySamples(const FunctionSamples *FS,
ProfileSummaryInfo *PSI) const;
void clear() {
SampleCoverage.clear();
TotalUsedSamples = 0;
}
private:
using BodySampleCoverageMap = std::map<LineLocation, unsigned>;
using FunctionSamplesCoverageMap =
DenseMap<const FunctionSamples *, BodySampleCoverageMap>;
/// Coverage map for sampling records.
///
/// This map keeps a record of sampling records that have been matched to
/// an IR instruction. This is used to detect some form of staleness in
/// profiles (see flag -sample-profile-check-coverage).
///
/// Each entry in the map corresponds to a FunctionSamples instance. This is
/// another map that counts how many times the sample record at the
/// given location has been used.
FunctionSamplesCoverageMap SampleCoverage;
/// Number of samples used from the profile.
///
/// When a sampling record is used for the first time, the samples from
/// that record are added to this accumulator. Coverage is later computed
/// based on the total number of samples available in this function and
/// its callsites.
///
/// Note that this accumulator tracks samples used from a single function
/// and all the inlined callsites. Strictly, we should have a map of counters
/// keyed by FunctionSamples pointers, but these stats are cleared after
/// every function, so we just need to keep a single counter.
uint64_t TotalUsedSamples = 0;
SampleProfileLoader &SPLoader;
};
class GUIDToFuncNameMapper {
public:
GUIDToFuncNameMapper(Module &M, SampleProfileReader &Reader,
DenseMap<uint64_t, StringRef> &GUIDToFuncNameMap)
: CurrentReader(Reader), CurrentModule(M),
CurrentGUIDToFuncNameMap(GUIDToFuncNameMap) {
if (!CurrentReader.useMD5())
return;
for (const auto &F : CurrentModule) {
StringRef OrigName = F.getName();
CurrentGUIDToFuncNameMap.insert(
{Function::getGUID(OrigName), OrigName});
// Local to global var promotion used by optimization like thinlto
// will rename the var and add suffix like ".llvm.xxx" to the
// original local name. In sample profile, the suffixes of function
// names are all stripped. Since it is possible that the mapper is
// built in post-thin-link phase and var promotion has been done,
// we need to add the substring of function name without the suffix
// into the GUIDToFuncNameMap.
StringRef CanonName = FunctionSamples::getCanonicalFnName(F);
if (CanonName != OrigName)
CurrentGUIDToFuncNameMap.insert(
{Function::getGUID(CanonName), CanonName});
}
// Update GUIDToFuncNameMap for each function including inlinees.
SetGUIDToFuncNameMapForAll(&CurrentGUIDToFuncNameMap);
}
~GUIDToFuncNameMapper() {
if (!CurrentReader.useMD5())
return;
CurrentGUIDToFuncNameMap.clear();
// Reset GUIDToFuncNameMap for of each function as they're no
// longer valid at this point.
SetGUIDToFuncNameMapForAll(nullptr);
}
private:
void SetGUIDToFuncNameMapForAll(DenseMap<uint64_t, StringRef> *Map) {
std::queue<FunctionSamples *> FSToUpdate;
for (auto &IFS : CurrentReader.getProfiles()) {
FSToUpdate.push(&IFS.second);
}
while (!FSToUpdate.empty()) {
FunctionSamples *FS = FSToUpdate.front();
FSToUpdate.pop();
FS->GUIDToFuncNameMap = Map;
for (const auto &ICS : FS->getCallsiteSamples()) {
const FunctionSamplesMap &FSMap = ICS.second;
for (auto &IFS : FSMap) {
FunctionSamples &FS = const_cast<FunctionSamples &>(IFS.second);
FSToUpdate.push(&FS);
}
}
}
}
SampleProfileReader &CurrentReader;
Module &CurrentModule;
DenseMap<uint64_t, StringRef> &CurrentGUIDToFuncNameMap;
};
// Inline candidate used by iterative callsite prioritized inliner
struct InlineCandidate {
CallBase *CallInstr;
const FunctionSamples *CalleeSamples;
// Prorated callsite count, which will be used to guide inlining. For example,
// if a callsite is duplicated in LTO prelink, then in LTO postlink the two
// copies will get their own distribution factors and their prorated counts
// will be used to decide if they should be inlined independently.
uint64_t CallsiteCount;
// Call site distribution factor to prorate the profile samples for a
// duplicated callsite. Default value is 1.0.
float CallsiteDistribution;
};
// Inline candidate comparer using call site weight
struct CandidateComparer {
bool operator()(const InlineCandidate &LHS, const InlineCandidate &RHS) {
if (LHS.CallsiteCount != RHS.CallsiteCount)
return LHS.CallsiteCount < RHS.CallsiteCount;
// Tie breaker using GUID so we have stable/deterministic inlining order
assert(LHS.CalleeSamples && RHS.CalleeSamples &&
"Expect non-null FunctionSamples");
return LHS.CalleeSamples->getGUID(LHS.CalleeSamples->getName()) <
RHS.CalleeSamples->getGUID(RHS.CalleeSamples->getName());
}
};
using CandidateQueue =
PriorityQueue<InlineCandidate, std::vector<InlineCandidate>,
CandidateComparer>;
/// Sample profile pass.
///
/// This pass reads profile data from the file specified by
/// -sample-profile-file and annotates every affected function with the
/// profile information found in that file.
class SampleProfileLoader {
public:
SampleProfileLoader(
StringRef Name, StringRef RemapName, ThinOrFullLTOPhase LTOPhase,
std::function<AssumptionCache &(Function &)> GetAssumptionCache,
std::function<TargetTransformInfo &(Function &)> GetTargetTransformInfo,
std::function<const TargetLibraryInfo &(Function &)> GetTLI)
: GetAC(std::move(GetAssumptionCache)),
GetTTI(std::move(GetTargetTransformInfo)), GetTLI(std::move(GetTLI)),
CoverageTracker(*this), Filename(std::string(Name)),
RemappingFilename(std::string(RemapName)), LTOPhase(LTOPhase) {}
bool doInitialization(Module &M, FunctionAnalysisManager *FAM = nullptr);
bool runOnModule(Module &M, ModuleAnalysisManager *AM,
ProfileSummaryInfo *_PSI, CallGraph *CG);
void dump() { Reader->dump(); }
protected:
friend class SampleCoverageTracker;
bool runOnFunction(Function &F, ModuleAnalysisManager *AM);
unsigned getFunctionLoc(Function &F);
bool emitAnnotations(Function &F);
ErrorOr<uint64_t> getInstWeight(const Instruction &I);
ErrorOr<uint64_t> getProbeWeight(const Instruction &I);
ErrorOr<uint64_t> getBlockWeight(const BasicBlock *BB);
const FunctionSamples *findCalleeFunctionSamples(const CallBase &I) const;
std::vector<const FunctionSamples *>
findIndirectCallFunctionSamples(const Instruction &I, uint64_t &Sum) const;
mutable DenseMap<const DILocation *, const FunctionSamples *> DILocation2SampleMap;
const FunctionSamples *findFunctionSamples(const Instruction &I) const;
// Attempt to promote indirect call and also inline the promoted call
bool tryPromoteAndInlineCandidate(
Function &F, InlineCandidate &Candidate, uint64_t SumOrigin,
uint64_t &Sum, DenseSet<Instruction *> &PromotedInsns,
SmallVector<CallBase *, 8> *InlinedCallSites = nullptr);
bool inlineHotFunctions(Function &F,
DenseSet<GlobalValue::GUID> &InlinedGUIDs);
InlineCost shouldInlineCandidate(InlineCandidate &Candidate);
bool getInlineCandidate(InlineCandidate *NewCandidate, CallBase *CB);
bool
tryInlineCandidate(InlineCandidate &Candidate,
SmallVector<CallBase *, 8> *InlinedCallSites = nullptr);
bool
inlineHotFunctionsWithPriority(Function &F,
DenseSet<GlobalValue::GUID> &InlinedGUIDs);
// Inline cold/small functions in addition to hot ones
bool shouldInlineColdCallee(CallBase &CallInst);
void emitOptimizationRemarksForInlineCandidates(
const SmallVectorImpl<CallBase *> &Candidates, const Function &F,
bool Hot);
void printEdgeWeight(raw_ostream &OS, Edge E);
void printBlockWeight(raw_ostream &OS, const BasicBlock *BB) const;
void printBlockEquivalence(raw_ostream &OS, const BasicBlock *BB);
bool computeBlockWeights(Function &F);
void findEquivalenceClasses(Function &F);
template <bool IsPostDom>
void findEquivalencesFor(BasicBlock *BB1, ArrayRef<BasicBlock *> Descendants,
DominatorTreeBase<BasicBlock, IsPostDom> *DomTree);
void propagateWeights(Function &F);
uint64_t visitEdge(Edge E, unsigned *NumUnknownEdges, Edge *UnknownEdge);
void buildEdges(Function &F);
std::vector<Function *> buildFunctionOrder(Module &M, CallGraph *CG);
void addCallGraphEdges(CallGraph &CG, const FunctionSamples &Samples);
void replaceCallGraphEdges(CallGraph &CG, StringMap<Function *> &SymbolMap);
bool propagateThroughEdges(Function &F, bool UpdateBlockCount);
void computeDominanceAndLoopInfo(Function &F);
void clearFunctionData();
bool callsiteIsHot(const FunctionSamples *CallsiteFS,
ProfileSummaryInfo *PSI);
/// Map basic blocks to their computed weights.
///
/// The weight of a basic block is defined to be the maximum
/// of all the instruction weights in that block.
BlockWeightMap BlockWeights;
/// Map edges to their computed weights.
///
/// Edge weights are computed by propagating basic block weights in
/// SampleProfile::propagateWeights.
EdgeWeightMap EdgeWeights;
/// Set of visited blocks during propagation.
SmallPtrSet<const BasicBlock *, 32> VisitedBlocks;
/// Set of visited edges during propagation.
SmallSet<Edge, 32> VisitedEdges;
/// Equivalence classes for block weights.
///
/// Two blocks BB1 and BB2 are in the same equivalence class if they
/// dominate and post-dominate each other, and they are in the same loop
/// nest. When this happens, the two blocks are guaranteed to execute
/// the same number of times.
EquivalenceClassMap EquivalenceClass;
/// Map from function name to Function *. Used to find the function from
/// the function name. If the function name contains suffix, additional
/// entry is added to map from the stripped name to the function if there
/// is one-to-one mapping.
StringMap<Function *> SymbolMap;
/// Dominance, post-dominance and loop information.
std::unique_ptr<DominatorTree> DT;
std::unique_ptr<PostDominatorTree> PDT;
std::unique_ptr<LoopInfo> LI;
std::function<AssumptionCache &(Function &)> GetAC;
std::function<TargetTransformInfo &(Function &)> GetTTI;
std::function<const TargetLibraryInfo &(Function &)> GetTLI;
/// Predecessors for each basic block in the CFG.
BlockEdgeMap Predecessors;
/// Successors for each basic block in the CFG.
BlockEdgeMap Successors;
SampleCoverageTracker CoverageTracker;
/// Profile reader object.
std::unique_ptr<SampleProfileReader> Reader;
/// Profile tracker for different context.
std::unique_ptr<SampleContextTracker> ContextTracker;
/// Samples collected for the body of this function.
FunctionSamples *Samples = nullptr;
/// Name of the profile file to load.
std::string Filename;
/// Name of the profile remapping file to load.
std::string RemappingFilename;
/// Flag indicating whether the profile input loaded successfully.
bool ProfileIsValid = false;
/// Flag indicating whether input profile is context-sensitive
bool ProfileIsCS = false;
/// Flag indicating which LTO/ThinLTO phase the pass is invoked in.
///
/// We need to know the LTO phase because for example in ThinLTOPrelink
/// phase, in annotation, we should not promote indirect calls. Instead,
/// we will mark GUIDs that needs to be annotated to the function.
ThinOrFullLTOPhase LTOPhase;
/// Profile Summary Info computed from sample profile.
ProfileSummaryInfo *PSI = nullptr;
/// Profle Symbol list tells whether a function name appears in the binary
/// used to generate the current profile.
std::unique_ptr<ProfileSymbolList> PSL;
/// Total number of samples collected in this profile.
///
/// This is the sum of all the samples collected in all the functions executed
/// at runtime.
uint64_t TotalCollectedSamples = 0;
/// Optimization Remark Emitter used to emit diagnostic remarks.
OptimizationRemarkEmitter *ORE = nullptr;
// Information recorded when we declined to inline a call site
// because we have determined it is too cold is accumulated for
// each callee function. Initially this is just the entry count.
struct NotInlinedProfileInfo {
uint64_t entryCount;
};
DenseMap<Function *, NotInlinedProfileInfo> notInlinedCallInfo;
// GUIDToFuncNameMap saves the mapping from GUID to the symbol name, for
// all the function symbols defined or declared in current module.
DenseMap<uint64_t, StringRef> GUIDToFuncNameMap;
// All the Names used in FunctionSamples including outline function
// names, inline instance names and call target names.
StringSet<> NamesInProfile;
// For symbol in profile symbol list, whether to regard their profiles
// to be accurate. It is mainly decided by existance of profile symbol
// list and -profile-accurate-for-symsinlist flag, but it can be
// overriden by -profile-sample-accurate or profile-sample-accurate
// attribute.
bool ProfAccForSymsInList;
// External inline advisor used to replay inline decision from remarks.
std::unique_ptr<ReplayInlineAdvisor> ExternalInlineAdvisor;
// A pseudo probe helper to correlate the imported sample counts.
std::unique_ptr<PseudoProbeManager> ProbeManager;
};
class SampleProfileLoaderLegacyPass : public ModulePass {
public:
// Class identification, replacement for typeinfo
static char ID;
SampleProfileLoaderLegacyPass(
StringRef Name = SampleProfileFile,
ThinOrFullLTOPhase LTOPhase = ThinOrFullLTOPhase::None)
: ModulePass(ID), SampleLoader(
Name, SampleProfileRemappingFile, LTOPhase,
[&](Function &F) -> AssumptionCache & {
return ACT->getAssumptionCache(F);
},
[&](Function &F) -> TargetTransformInfo & {
return TTIWP->getTTI(F);
},
[&](Function &F) -> TargetLibraryInfo & {
return TLIWP->getTLI(F);
}) {
initializeSampleProfileLoaderLegacyPassPass(
*PassRegistry::getPassRegistry());
}
void dump() { SampleLoader.dump(); }
bool doInitialization(Module &M) override {
return SampleLoader.doInitialization(M);
}
StringRef getPassName() const override { return "Sample profile pass"; }
bool runOnModule(Module &M) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<AssumptionCacheTracker>();
AU.addRequired<TargetTransformInfoWrapperPass>();
AU.addRequired<TargetLibraryInfoWrapperPass>();
AU.addRequired<ProfileSummaryInfoWrapperPass>();
}
private:
SampleProfileLoader SampleLoader;
AssumptionCacheTracker *ACT = nullptr;
TargetTransformInfoWrapperPass *TTIWP = nullptr;
TargetLibraryInfoWrapperPass *TLIWP = nullptr;
};
} // end anonymous namespace
/// Return true if the given callsite is hot wrt to hot cutoff threshold.
///
/// Functions that were inlined in the original binary will be represented
/// in the inline stack in the sample profile. If the profile shows that
/// the original inline decision was "good" (i.e., the callsite is executed
/// frequently), then we will recreate the inline decision and apply the
/// profile from the inlined callsite.
///
/// To decide whether an inlined callsite is hot, we compare the callsite
/// sample count with the hot cutoff computed by ProfileSummaryInfo, it is
/// regarded as hot if the count is above the cutoff value.
///
/// When ProfileAccurateForSymsInList is enabled and profile symbol list
/// is present, functions in the profile symbol list but without profile will
/// be regarded as cold and much less inlining will happen in CGSCC inlining
/// pass, so we tend to lower the hot criteria here to allow more early
/// inlining to happen for warm callsites and it is helpful for performance.
bool SampleProfileLoader::callsiteIsHot(const FunctionSamples *CallsiteFS,
ProfileSummaryInfo *PSI) {
if (!CallsiteFS)
return false; // The callsite was not inlined in the original binary.
assert(PSI && "PSI is expected to be non null");
uint64_t CallsiteTotalSamples = CallsiteFS->getTotalSamples();
if (ProfAccForSymsInList)
return !PSI->isColdCount(CallsiteTotalSamples);
else
return PSI->isHotCount(CallsiteTotalSamples);
}
/// Mark as used the sample record for the given function samples at
/// (LineOffset, Discriminator).
///
/// \returns true if this is the first time we mark the given record.
bool SampleCoverageTracker::markSamplesUsed(const FunctionSamples *FS,
uint32_t LineOffset,
uint32_t Discriminator,
uint64_t Samples) {
LineLocation Loc(LineOffset, Discriminator);
unsigned &Count = SampleCoverage[FS][Loc];
bool FirstTime = (++Count == 1);
if (FirstTime)
TotalUsedSamples += Samples;
return FirstTime;
}
/// Return the number of sample records that were applied from this profile.
///
/// This count does not include records from cold inlined callsites.
unsigned
SampleCoverageTracker::countUsedRecords(const FunctionSamples *FS,
ProfileSummaryInfo *PSI) const {
auto I = SampleCoverage.find(FS);
// The size of the coverage map for FS represents the number of records
// that were marked used at least once.
unsigned Count = (I != SampleCoverage.end()) ? I->second.size() : 0;
// If there are inlined callsites in this function, count the samples found
// in the respective bodies. However, do not bother counting callees with 0
// total samples, these are callees that were never invoked at runtime.
for (const auto &I : FS->getCallsiteSamples())
for (const auto &J : I.second) {
const FunctionSamples *CalleeSamples = &J.second;
if (SPLoader.callsiteIsHot(CalleeSamples, PSI))
Count += countUsedRecords(CalleeSamples, PSI);
}
return Count;
}
/// Return the number of sample records in the body of this profile.
///
/// This count does not include records from cold inlined callsites.
unsigned
SampleCoverageTracker::countBodyRecords(const FunctionSamples *FS,
ProfileSummaryInfo *PSI) const {
unsigned Count = FS->getBodySamples().size();
// Only count records in hot callsites.
for (const auto &I : FS->getCallsiteSamples())
for (const auto &J : I.second) {
const FunctionSamples *CalleeSamples = &J.second;
if (SPLoader.callsiteIsHot(CalleeSamples, PSI))
Count += countBodyRecords(CalleeSamples, PSI);
}
return Count;
}
/// Return the number of samples collected in the body of this profile.
///
/// This count does not include samples from cold inlined callsites.
uint64_t
SampleCoverageTracker::countBodySamples(const FunctionSamples *FS,
ProfileSummaryInfo *PSI) const {
uint64_t Total = 0;
for (const auto &I : FS->getBodySamples())
Total += I.second.getSamples();
// Only count samples in hot callsites.
for (const auto &I : FS->getCallsiteSamples())
for (const auto &J : I.second) {
const FunctionSamples *CalleeSamples = &J.second;
if (SPLoader.callsiteIsHot(CalleeSamples, PSI))
Total += countBodySamples(CalleeSamples, PSI);
}
return Total;
}
/// Return the fraction of sample records used in this profile.
///
/// The returned value is an unsigned integer in the range 0-100 indicating
/// the percentage of sample records that were used while applying this
/// profile to the associated function.
unsigned SampleCoverageTracker::computeCoverage(unsigned Used,
unsigned Total) const {
assert(Used <= Total &&
"number of used records cannot exceed the total number of records");
return Total > 0 ? Used * 100 / Total : 100;
}
/// Clear all the per-function data used to load samples and propagate weights.
void SampleProfileLoader::clearFunctionData() {
BlockWeights.clear();
EdgeWeights.clear();
VisitedBlocks.clear();
VisitedEdges.clear();
EquivalenceClass.clear();
DT = nullptr;
PDT = nullptr;
LI = nullptr;
Predecessors.clear();
Successors.clear();
CoverageTracker.clear();
}
#ifndef NDEBUG
/// Print the weight of edge \p E on stream \p OS.
///
/// \param OS Stream to emit the output to.
/// \param E Edge to print.
void SampleProfileLoader::printEdgeWeight(raw_ostream &OS, Edge E) {
OS << "weight[" << E.first->getName() << "->" << E.second->getName()
<< "]: " << EdgeWeights[E] << "\n";
}
/// Print the equivalence class of block \p BB on stream \p OS.
///
/// \param OS Stream to emit the output to.
/// \param BB Block to print.
void SampleProfileLoader::printBlockEquivalence(raw_ostream &OS,
const BasicBlock *BB) {
const BasicBlock *Equiv = EquivalenceClass[BB];
OS << "equivalence[" << BB->getName()
<< "]: " << ((Equiv) ? EquivalenceClass[BB]->getName() : "NONE") << "\n";
}
/// Print the weight of block \p BB on stream \p OS.
///
/// \param OS Stream to emit the output to.
/// \param BB Block to print.
void SampleProfileLoader::printBlockWeight(raw_ostream &OS,
const BasicBlock *BB) const {
const auto &I = BlockWeights.find(BB);
uint64_t W = (I == BlockWeights.end() ? 0 : I->second);
OS << "weight[" << BB->getName() << "]: " << W << "\n";
}
#endif
/// Get the weight for an instruction.
///
/// The "weight" of an instruction \p Inst is the number of samples
/// collected on that instruction at runtime. To retrieve it, we
/// need to compute the line number of \p Inst relative to the start of its
/// function. We use HeaderLineno to compute the offset. We then
/// look up the samples collected for \p Inst using BodySamples.
///
/// \param Inst Instruction to query.
///
/// \returns the weight of \p Inst.
ErrorOr<uint64_t> SampleProfileLoader::getInstWeight(const Instruction &Inst) {
if (FunctionSamples::ProfileIsProbeBased)
return getProbeWeight(Inst);
const DebugLoc &DLoc = Inst.getDebugLoc();
if (!DLoc)
return std::error_code();
const FunctionSamples *FS = findFunctionSamples(Inst);
if (!FS)
return std::error_code();
// Ignore all intrinsics, phinodes and branch instructions.
// Branch and phinodes instruction usually contains debug info from sources outside of
// the residing basic block, thus we ignore them during annotation.
if (isa<BranchInst>(Inst) || isa<IntrinsicInst>(Inst) || isa<PHINode>(Inst))
return std::error_code();
// If a direct call/invoke instruction is inlined in profile
// (findCalleeFunctionSamples returns non-empty result), but not inlined here,
// it means that the inlined callsite has no sample, thus the call
// instruction should have 0 count.
if (!ProfileIsCS)
if (const auto *CB = dyn_cast<CallBase>(&Inst))
if (!CB->isIndirectCall() && findCalleeFunctionSamples(*CB))
return 0;
const DILocation *DIL = DLoc;
uint32_t LineOffset = FunctionSamples::getOffset(DIL);
uint32_t Discriminator = DIL->getBaseDiscriminator();
ErrorOr<uint64_t> R = FS->findSamplesAt(LineOffset, Discriminator);
if (R) {
bool FirstMark =
CoverageTracker.markSamplesUsed(FS, LineOffset, Discriminator, R.get());
if (FirstMark) {
ORE->emit([&]() {
OptimizationRemarkAnalysis Remark(DEBUG_TYPE, "AppliedSamples", &Inst);
Remark << "Applied " << ore::NV("NumSamples", *R);
Remark << " samples from profile (offset: ";
Remark << ore::NV("LineOffset", LineOffset);
if (Discriminator) {
Remark << ".";
Remark << ore::NV("Discriminator", Discriminator);
}
Remark << ")";
return Remark;
});
}
LLVM_DEBUG(dbgs() << " " << DLoc.getLine() << "."
<< DIL->getBaseDiscriminator() << ":" << Inst
<< " (line offset: " << LineOffset << "."
<< DIL->getBaseDiscriminator() << " - weight: " << R.get()
<< ")\n");
}
return R;
}
ErrorOr<uint64_t> SampleProfileLoader::getProbeWeight(const Instruction &Inst) {
assert(FunctionSamples::ProfileIsProbeBased &&
"Profile is not pseudo probe based");
Optional<PseudoProbe> Probe = extractProbe(Inst);
if (!Probe)
return std::error_code();
const FunctionSamples *FS = findFunctionSamples(Inst);
if (!FS)
return std::error_code();
// If a direct call/invoke instruction is inlined in profile
// (findCalleeFunctionSamples returns non-empty result), but not inlined here,
// it means that the inlined callsite has no sample, thus the call
// instruction should have 0 count.
if (const auto *CB = dyn_cast<CallBase>(&Inst))
if (!CB->isIndirectCall() && findCalleeFunctionSamples(*CB))
return 0;
const ErrorOr<uint64_t> &R = FS->findSamplesAt(Probe->Id, 0);
if (R) {
uint64_t Samples = R.get() * Probe->Factor;
bool FirstMark = CoverageTracker.markSamplesUsed(FS, Probe->Id, 0, Samples);
if (FirstMark) {
ORE->emit([&]() {
OptimizationRemarkAnalysis Remark(DEBUG_TYPE, "AppliedSamples", &Inst);
Remark << "Applied " << ore::NV("NumSamples", Samples);
Remark << " samples from profile (ProbeId=";
Remark << ore::NV("ProbeId", Probe->Id);
Remark << ", Factor=";
Remark << ore::NV("Factor", Probe->Factor);
Remark << ", OriginalSamples=";
Remark << ore::NV("OriginalSamples", R.get());
Remark << ")";
return Remark;
});
}
LLVM_DEBUG(dbgs() << " " << Probe->Id << ":" << Inst
<< " - weight: " << R.get() << " - factor: "
<< format("%0.2f", Probe->Factor) << ")\n");
return Samples;
}
return R;
}
/// Compute the weight of a basic block.
///
/// The weight of basic block \p BB is the maximum weight of all the
/// instructions in BB.
///
/// \param BB The basic block to query.
///
/// \returns the weight for \p BB.
ErrorOr<uint64_t> SampleProfileLoader::getBlockWeight(const BasicBlock *BB) {
uint64_t Max = 0;
bool HasWeight = false;
for (auto &I : BB->getInstList()) {
const ErrorOr<uint64_t> &R = getInstWeight(I);
if (R) {
Max = std::max(Max, R.get());
HasWeight = true;
}
}
return HasWeight ? ErrorOr<uint64_t>(Max) : std::error_code();
}
/// Compute and store the weights of every basic block.
///
/// This populates the BlockWeights map by computing
/// the weights of every basic block in the CFG.
///
/// \param F The function to query.
bool SampleProfileLoader::computeBlockWeights(Function &F) {
bool Changed = false;
LLVM_DEBUG(dbgs() << "Block weights\n");
for (const auto &BB : F) {
ErrorOr<uint64_t> Weight = getBlockWeight(&BB);
if (Weight) {
BlockWeights[&BB] = Weight.get();
VisitedBlocks.insert(&BB);
Changed = true;
}
LLVM_DEBUG(printBlockWeight(dbgs(), &BB));
}
return Changed;
}
/// Get the FunctionSamples for a call instruction.
///
/// The FunctionSamples of a call/invoke instruction \p Inst is the inlined
/// instance in which that call instruction is calling to. It contains
/// all samples that resides in the inlined instance. We first find the
/// inlined instance in which the call instruction is from, then we
/// traverse its children to find the callsite with the matching
/// location.
///
/// \param Inst Call/Invoke instruction to query.
///
/// \returns The FunctionSamples pointer to the inlined instance.
const FunctionSamples *
SampleProfileLoader::findCalleeFunctionSamples(const CallBase &Inst) const {
const DILocation *DIL = Inst.getDebugLoc();
if (!DIL) {
return nullptr;
}
StringRef CalleeName;
if (Function *Callee = Inst.getCalledFunction())
CalleeName = FunctionSamples::getCanonicalFnName(*Callee);
if (ProfileIsCS)
return ContextTracker->getCalleeContextSamplesFor(Inst, CalleeName);
const FunctionSamples *FS = findFunctionSamples(Inst);
if (FS == nullptr)
return nullptr;
return FS->findFunctionSamplesAt(FunctionSamples::getCallSiteIdentifier(DIL),
CalleeName, Reader->getRemapper());
}
/// Returns a vector of FunctionSamples that are the indirect call targets
/// of \p Inst. The vector is sorted by the total number of samples. Stores
/// the total call count of the indirect call in \p Sum.
std::vector<const FunctionSamples *>
SampleProfileLoader::findIndirectCallFunctionSamples(
const Instruction &Inst, uint64_t &Sum) const {
const DILocation *DIL = Inst.getDebugLoc();
std::vector<const FunctionSamples *> R;
if (!DIL) {
return R;
}
auto FSCompare = [](const FunctionSamples *L, const FunctionSamples *R) {
assert(L && R && "Expect non-null FunctionSamples");
if (L->getEntrySamples() != R->getEntrySamples())
return L->getEntrySamples() > R->getEntrySamples();
return FunctionSamples::getGUID(L->getName()) <
FunctionSamples::getGUID(R->getName());
};
if (ProfileIsCS) {
auto CalleeSamples =
ContextTracker->getIndirectCalleeContextSamplesFor(DIL);
if (CalleeSamples.empty())
return R;
// For CSSPGO, we only use target context profile's entry count
// as that already includes both inlined callee and non-inlined ones..
Sum = 0;
for (const auto *const FS : CalleeSamples) {
Sum += FS->getEntrySamples();
R.push_back(FS);
}
llvm::sort(R, FSCompare);
return R;
}
const FunctionSamples *FS = findFunctionSamples(Inst);
if (FS == nullptr)
return R;
auto CallSite = FunctionSamples::getCallSiteIdentifier(DIL);
auto T = FS->findCallTargetMapAt(CallSite);
Sum = 0;
if (T)
for (const auto &T_C : T.get())
Sum += T_C.second;
if (const FunctionSamplesMap *M = FS->findFunctionSamplesMapAt(CallSite)) {
if (M->empty())
return R;
for (const auto &NameFS : *M) {
Sum += NameFS.second.getEntrySamples();
R.push_back(&NameFS.second);
}
llvm::sort(R, FSCompare);
}
return R;
}
/// Get the FunctionSamples for an instruction.
///
/// The FunctionSamples of an instruction \p Inst is the inlined instance
/// in which that instruction is coming from. We traverse the inline stack
/// of that instruction, and match it with the tree nodes in the profile.
///
/// \param Inst Instruction to query.
///
/// \returns the FunctionSamples pointer to the inlined instance.
const FunctionSamples *
SampleProfileLoader::findFunctionSamples(const Instruction &Inst) const {
if (FunctionSamples::ProfileIsProbeBased) {
Optional<PseudoProbe> Probe = extractProbe(Inst);
if (!Probe)
return nullptr;
}
const DILocation *DIL = Inst.getDebugLoc();
if (!DIL)
return Samples;
auto it = DILocation2SampleMap.try_emplace(DIL,nullptr);
if (it.second) {
if (ProfileIsCS)
it.first->second = ContextTracker->getContextSamplesFor(DIL);
else
it.first->second =
Samples->findFunctionSamples(DIL, Reader->getRemapper());
}
return it.first->second;
}
/// Attempt to promote indirect call and also inline the promoted call.
///
/// \param F Caller function.
/// \param Candidate ICP and inline candidate.
/// \param Sum Sum of target counts for indirect call.
/// \param PromotedInsns Map to keep track of indirect call already processed.
/// \param Candidate ICP and inline candidate.
/// \param InlinedCallSite Output vector for new call sites exposed after
/// inlining.
bool SampleProfileLoader::tryPromoteAndInlineCandidate(
Function &F, InlineCandidate &Candidate, uint64_t SumOrigin, uint64_t &Sum,
DenseSet<Instruction *> &PromotedInsns,
SmallVector<CallBase *, 8> *InlinedCallSite) {
const char *Reason = "Callee function not available";
// R->getValue() != &F is to prevent promoting a recursive call.
// If it is a recursive call, we do not inline it as it could bloat
// the code exponentially. There is way to better handle this, e.g.
// clone the caller first, and inline the cloned caller if it is
// recursive. As llvm does not inline recursive calls, we will
// simply ignore it instead of handling it explicitly.
auto R = SymbolMap.find(Candidate.CalleeSamples->getFuncName());
if (R != SymbolMap.end() && R->getValue() &&
!R->getValue()->isDeclaration() && R->getValue()->getSubprogram() &&
R->getValue()->hasFnAttribute("use-sample-profile") &&
R->getValue() != &F &&
isLegalToPromote(*Candidate.CallInstr, R->getValue(), &Reason)) {
auto *DI =
&pgo::promoteIndirectCall(*Candidate.CallInstr, R->getValue(),
Candidate.CallsiteCount, Sum, false, ORE);
if (DI) {
Sum -= Candidate.CallsiteCount;
// Prorate the indirect callsite distribution.
// Do not update the promoted direct callsite distribution at this
// point since the original distribution combined with the callee
// profile will be used to prorate callsites from the callee if
// inlined. Once not inlined, the direct callsite distribution should
// be prorated so that the it will reflect the real callsite counts.
setProbeDistributionFactor(*Candidate.CallInstr,
Candidate.CallsiteDistribution * Sum /
SumOrigin);
PromotedInsns.insert(Candidate.CallInstr);
Candidate.CallInstr = DI;
if (isa<CallInst>(DI) || isa<InvokeInst>(DI)) {
bool Inlined = tryInlineCandidate(Candidate, InlinedCallSite);
if (!Inlined) {
// Prorate the direct callsite distribution so that it reflects real
// callsite counts.
setProbeDistributionFactor(*DI, Candidate.CallsiteDistribution *
Candidate.CallsiteCount /
SumOrigin);
}
return Inlined;
}
}
} else {
LLVM_DEBUG(dbgs() << "\nFailed to promote indirect call to "
<< Candidate.CalleeSamples->getFuncName() << " because "
<< Reason << "\n");
}
return false;
}
bool SampleProfileLoader::shouldInlineColdCallee(CallBase &CallInst) {
if (!ProfileSizeInline)
return false;
Function *Callee = CallInst.getCalledFunction();
if (Callee == nullptr)
return false;
InlineCost Cost = getInlineCost(CallInst, getInlineParams(), GetTTI(*Callee),
GetAC, GetTLI);
if (Cost.isNever())
return false;
if (Cost.isAlways())
return true;
return Cost.getCost() <= SampleColdCallSiteThreshold;
}
void SampleProfileLoader::emitOptimizationRemarksForInlineCandidates(
const SmallVectorImpl<CallBase *> &Candidates, const Function &F,
bool Hot) {
for (auto I : Candidates) {
Function *CalledFunction = I->getCalledFunction();
if (CalledFunction) {
ORE->emit(OptimizationRemarkAnalysis(CSINLINE_DEBUG, "InlineAttempt",
I->getDebugLoc(), I->getParent())
<< "previous inlining reattempted for "
<< (Hot ? "hotness: '" : "size: '")
<< ore::NV("Callee", CalledFunction) << "' into '"
<< ore::NV("Caller", &F) << "'");
}
}
}
/// Iteratively inline hot callsites of a function.
///
/// Iteratively traverse all callsites of the function \p F, and find if
/// the corresponding inlined instance exists and is hot in profile. If
/// it is hot enough, inline the callsites and adds new callsites of the
/// callee into the caller. If the call is an indirect call, first promote
/// it to direct call. Each indirect call is limited with a single target.
///
/// \param F function to perform iterative inlining.
/// \param InlinedGUIDs a set to be updated to include all GUIDs that are
/// inlined in the profiled binary.
///
/// \returns True if there is any inline happened.
bool SampleProfileLoader::inlineHotFunctions(
Function &F, DenseSet<GlobalValue::GUID> &InlinedGUIDs) {
DenseSet<Instruction *> PromotedInsns;
// ProfAccForSymsInList is used in callsiteIsHot. The assertion makes sure
// Profile symbol list is ignored when profile-sample-accurate is on.
assert((!ProfAccForSymsInList ||
(!ProfileSampleAccurate &&
!F.hasFnAttribute("profile-sample-accurate"))) &&
"ProfAccForSymsInList should be false when profile-sample-accurate "
"is enabled");
DenseMap<CallBase *, const FunctionSamples *> LocalNotInlinedCallSites;
bool Changed = false;
bool LocalChanged = true;
while (LocalChanged) {
LocalChanged = false;
SmallVector<CallBase *, 10> CIS;
for (auto &BB : F) {
bool Hot = false;
SmallVector<CallBase *, 10> AllCandidates;
SmallVector<CallBase *, 10> ColdCandidates;
for (auto &I : BB.getInstList()) {
const FunctionSamples *FS = nullptr;
if (auto *CB = dyn_cast<CallBase>(&I)) {
if (!isa<IntrinsicInst>(I) && (FS = findCalleeFunctionSamples(*CB))) {
assert((!FunctionSamples::UseMD5 || FS->GUIDToFuncNameMap) &&
"GUIDToFuncNameMap has to be populated");
AllCandidates.push_back(CB);
if (FS->getEntrySamples() > 0 || ProfileIsCS)
LocalNotInlinedCallSites.try_emplace(CB, FS);
if (callsiteIsHot(FS, PSI))
Hot = true;
else if (shouldInlineColdCallee(*CB))
ColdCandidates.push_back(CB);
}
}
}
if (Hot || ExternalInlineAdvisor) {
CIS.insert(CIS.begin(), AllCandidates.begin(), AllCandidates.end());
emitOptimizationRemarksForInlineCandidates(AllCandidates, F, true);
} else {
CIS.insert(CIS.begin(), ColdCandidates.begin(), ColdCandidates.end());
emitOptimizationRemarksForInlineCandidates(ColdCandidates, F, false);
}
}
for (CallBase *I : CIS) {
Function *CalledFunction = I->getCalledFunction();
InlineCandidate Candidate = {
I,
LocalNotInlinedCallSites.count(I) ? LocalNotInlinedCallSites[I]
: nullptr,
0 /* dummy count */, 1.0 /* dummy distribution factor */};
// Do not inline recursive calls.
if (CalledFunction == &F)
continue;
if (I->isIndirectCall()) {
if (PromotedInsns.count(I))
continue;
uint64_t Sum;
for (const auto *FS : findIndirectCallFunctionSamples(*I, Sum)) {
uint64_t SumOrigin = Sum;
if (LTOPhase == ThinOrFullLTOPhase::ThinLTOPreLink) {
FS->findInlinedFunctions(InlinedGUIDs, F.getParent(),
PSI->getOrCompHotCountThreshold());
continue;
}
if (!callsiteIsHot(FS, PSI))
continue;
Candidate = {I, FS, FS->getEntrySamples(), 1.0};
if (tryPromoteAndInlineCandidate(F, Candidate, SumOrigin, Sum,
PromotedInsns)) {
LocalNotInlinedCallSites.erase(I);
LocalChanged = true;
}
}
} else if (CalledFunction && CalledFunction->getSubprogram() &&
!CalledFunction->isDeclaration()) {
if (tryInlineCandidate(Candidate)) {
LocalNotInlinedCallSites.erase(I);
LocalChanged = true;
}
} else if (LTOPhase == ThinOrFullLTOPhase::ThinLTOPreLink) {
findCalleeFunctionSamples(*I)->findInlinedFunctions(
InlinedGUIDs, F.getParent(), PSI->getOrCompHotCountThreshold());
}
}
Changed |= LocalChanged;
}
// For CS profile, profile for not inlined context will be merged when
// base profile is being trieved
if (ProfileIsCS)
return Changed;
// Accumulate not inlined callsite information into notInlinedSamples
for (const auto &Pair : LocalNotInlinedCallSites) {
CallBase *I = Pair.getFirst();
Function *Callee = I->getCalledFunction();
if (!Callee || Callee->isDeclaration())
continue;
ORE->emit(OptimizationRemarkAnalysis(CSINLINE_DEBUG, "NotInline",
I->getDebugLoc(), I->getParent())
<< "previous inlining not repeated: '"
<< ore::NV("Callee", Callee) << "' into '"
<< ore::NV("Caller", &F) << "'");
++NumCSNotInlined;
const FunctionSamples *FS = Pair.getSecond();
if (FS->getTotalSamples() == 0 && FS->getEntrySamples() == 0) {
continue;
}
if (ProfileMergeInlinee) {
// A function call can be replicated by optimizations like callsite
// splitting or jump threading and the replicates end up sharing the
// sample nested callee profile instead of slicing the original inlinee's
// profile. We want to do merge exactly once by filtering out callee
// profiles with a non-zero head sample count.
if (FS->getHeadSamples() == 0) {
// Use entry samples as head samples during the merge, as inlinees
// don't have head samples.
const_cast<FunctionSamples *>(FS)->addHeadSamples(
FS->getEntrySamples());
// Note that we have to do the merge right after processing function.
// This allows OutlineFS's profile to be used for annotation during
// top-down processing of functions' annotation.
FunctionSamples *OutlineFS = Reader->getOrCreateSamplesFor(*Callee);
OutlineFS->merge(*FS);
}
} else {
auto pair =
notInlinedCallInfo.try_emplace(Callee, NotInlinedProfileInfo{0});
pair.first->second.entryCount += FS->getEntrySamples();
}
}
return Changed;
}
bool SampleProfileLoader::tryInlineCandidate(
InlineCandidate &Candidate, SmallVector<CallBase *, 8> *InlinedCallSites) {
CallBase &CB = *Candidate.CallInstr;
Function *CalledFunction = CB.getCalledFunction();
assert(CalledFunction && "Expect a callee with definition");
DebugLoc DLoc = CB.getDebugLoc();
BasicBlock *BB = CB.getParent();
InlineCost Cost = shouldInlineCandidate(Candidate);
if (Cost.isNever()) {
ORE->emit(OptimizationRemarkAnalysis(CSINLINE_DEBUG, "InlineFail", DLoc, BB)
<< "incompatible inlining");
return false;
}
if (!Cost)
return false;
InlineFunctionInfo IFI(nullptr, GetAC);
if (InlineFunction(CB, IFI).isSuccess()) {
// The call to InlineFunction erases I, so we can't pass it here.
emitInlinedInto(*ORE, DLoc, BB, *CalledFunction, *BB->getParent(), Cost,
true, CSINLINE_DEBUG);
// Now populate the list of newly exposed call sites.
if (InlinedCallSites) {
InlinedCallSites->clear();
for (auto &I : IFI.InlinedCallSites)
InlinedCallSites->push_back(I);
}
if (ProfileIsCS)
ContextTracker->markContextSamplesInlined(Candidate.CalleeSamples);
++NumCSInlined;
// Prorate inlined probes for a duplicated inlining callsite which probably
// has a distribution less than 100%. Samples for an inlinee should be
// distributed among the copies of the original callsite based on each
// callsite's distribution factor for counts accuracy. Note that an inlined
// probe may come with its own distribution factor if it has been duplicated
// in the inlinee body. The two factor are multiplied to reflect the
// aggregation of duplication.
if (Candidate.CallsiteDistribution < 1) {
for (auto &I : IFI.InlinedCallSites) {
if (Optional<PseudoProbe> Probe = extractProbe(*I))
setProbeDistributionFactor(*I, Probe->Factor *
Candidate.CallsiteDistribution);
}
NumDuplicatedInlinesite++;
}
return true;
}
return false;
}
bool SampleProfileLoader::getInlineCandidate(InlineCandidate *NewCandidate,
CallBase *CB) {
assert(CB && "Expect non-null call instruction");
if (isa<IntrinsicInst>(CB))
return false;
// Find the callee's profile. For indirect call, find hottest target profile.
const FunctionSamples *CalleeSamples = findCalleeFunctionSamples(*CB);
if (!CalleeSamples)
return false;
float Factor = 1.0;
if (Optional<PseudoProbe> Probe = extractProbe(*CB))
Factor = Probe->Factor;
uint64_t CallsiteCount = 0;
ErrorOr<uint64_t> Weight = getBlockWeight(CB->getParent());
if (Weight)
CallsiteCount = Weight.get();
if (CalleeSamples)
CallsiteCount = std::max(
CallsiteCount, uint64_t(CalleeSamples->getEntrySamples() * Factor));
*NewCandidate = {CB, CalleeSamples, CallsiteCount, Factor};
return true;
}
InlineCost
SampleProfileLoader::shouldInlineCandidate(InlineCandidate &Candidate) {
std::unique_ptr<InlineAdvice> Advice = nullptr;
if (ExternalInlineAdvisor) {
Advice = ExternalInlineAdvisor->getAdvice(*Candidate.CallInstr);
if (!Advice->isInliningRecommended()) {
Advice->recordUnattemptedInlining();
return InlineCost::getNever("not previously inlined");
}
Advice->recordInlining();
return InlineCost::getAlways("previously inlined");
}
// Adjust threshold based on call site hotness, only do this for callsite
// prioritized inliner because otherwise cost-benefit check is done earlier.
int SampleThreshold = SampleColdCallSiteThreshold;
if (CallsitePrioritizedInline) {
if (Candidate.CallsiteCount > PSI->getHotCountThreshold())
SampleThreshold = SampleHotCallSiteThreshold;
else if (!ProfileSizeInline)
return InlineCost::getNever("cold callsite");
}
Function *Callee = Candidate.CallInstr->getCalledFunction();
assert(Callee && "Expect a definition for inline candidate of direct call");
InlineParams Params = getInlineParams();
Params.ComputeFullInlineCost = true;
// Checks if there is anything in the reachable portion of the callee at
// this callsite that makes this inlining potentially illegal. Need to
// set ComputeFullInlineCost, otherwise getInlineCost may return early
// when cost exceeds threshold without checking all IRs in the callee.
// The acutal cost does not matter because we only checks isNever() to
// see if it is legal to inline the callsite.
InlineCost Cost = getInlineCost(*Candidate.CallInstr, Callee, Params,
GetTTI(*Callee), GetAC, GetTLI);
// Honor always inline and never inline from call analyzer
if (Cost.isNever() || Cost.isAlways())
return Cost;
// For old FDO inliner, we inline the call site as long as cost is not
// "Never". The cost-benefit check is done earlier.
if (!CallsitePrioritizedInline) {
return InlineCost::get(Cost.getCost(), INT_MAX);
}
// Otherwise only use the cost from call analyzer, but overwite threshold with
// Sample PGO threshold.
return InlineCost::get(Cost.getCost(), SampleThreshold);
}
bool SampleProfileLoader::inlineHotFunctionsWithPriority(
Function &F, DenseSet<GlobalValue::GUID> &InlinedGUIDs) {
DenseSet<Instruction *> PromotedInsns;
assert(ProfileIsCS && "Prioritiy based inliner only works with CSSPGO now");
// ProfAccForSymsInList is used in callsiteIsHot. The assertion makes sure
// Profile symbol list is ignored when profile-sample-accurate is on.
assert((!ProfAccForSymsInList ||
(!ProfileSampleAccurate &&
!F.hasFnAttribute("profile-sample-accurate"))) &&
"ProfAccForSymsInList should be false when profile-sample-accurate "
"is enabled");
// Populating worklist with initial call sites from root inliner, along
// with call site weights.
CandidateQueue CQueue;
InlineCandidate NewCandidate;
for (auto &BB : F) {
for (auto &I : BB.getInstList()) {
auto *CB = dyn_cast<CallBase>(&I);
if (!CB)
continue;
if (getInlineCandidate(&NewCandidate, CB))
CQueue.push(NewCandidate);
}
}
// Cap the size growth from profile guided inlining. This is needed even
// though cost of each inline candidate already accounts for callee size,
// because with top-down inlining, we can grow inliner size significantly
// with large number of smaller inlinees each pass the cost check.
assert(ProfileInlineLimitMax >= ProfileInlineLimitMin &&
"Max inline size limit should not be smaller than min inline size "
"limit.");
unsigned SizeLimit = F.getInstructionCount() * ProfileInlineGrowthLimit;
SizeLimit = std::min(SizeLimit, (unsigned)ProfileInlineLimitMax);
SizeLimit = std::max(SizeLimit, (unsigned)ProfileInlineLimitMin);
if (ExternalInlineAdvisor)
SizeLimit = std::numeric_limits<unsigned>::max();
// Perform iterative BFS call site prioritized inlining
bool Changed = false;
while (!CQueue.empty() && F.getInstructionCount() < SizeLimit) {
InlineCandidate Candidate = CQueue.top();
CQueue.pop();
CallBase *I = Candidate.CallInstr;
Function *CalledFunction = I->getCalledFunction();
if (CalledFunction == &F)
continue;
if (I->isIndirectCall()) {
if (PromotedInsns.count(I))
continue;
uint64_t Sum;
auto CalleeSamples = findIndirectCallFunctionSamples(*I, Sum);
uint64_t SumOrigin = Sum;
Sum *= Candidate.CallsiteDistribution;
for (const auto *FS : CalleeSamples) {
// TODO: Consider disable pre-lTO ICP for MonoLTO as well
if (LTOPhase == ThinOrFullLTOPhase::ThinLTOPreLink) {
FS->findInlinedFunctions(InlinedGUIDs, F.getParent(),
PSI->getOrCompHotCountThreshold());
continue;
}
uint64_t EntryCountDistributed =
FS->getEntrySamples() * Candidate.CallsiteDistribution;
// In addition to regular inline cost check, we also need to make sure
// ICP isn't introducing excessive speculative checks even if individual
// target looks beneficial to promote and inline. That means we should
// only do ICP when there's a small number dominant targets.
if (EntryCountDistributed < SumOrigin / ProfileICPThreshold)
break;
// TODO: Fix CallAnalyzer to handle all indirect calls.
// For indirect call, we don't run CallAnalyzer to get InlineCost
// before actual inlining. This is because we could see two different
// types from the same definition, which makes CallAnalyzer choke as
// it's expecting matching parameter type on both caller and callee
// side. See example from PR18962 for the triggering cases (the bug was
// fixed, but we generate different types).
if (!PSI->isHotCount(EntryCountDistributed))
break;
SmallVector<CallBase *, 8> InlinedCallSites;
// Attach function profile for promoted indirect callee, and update
// call site count for the promoted inline candidate too.
Candidate = {I, FS, EntryCountDistributed,
Candidate.CallsiteDistribution};
if (tryPromoteAndInlineCandidate(F, Candidate, SumOrigin, Sum,
PromotedInsns, &InlinedCallSites)) {
for (auto *CB : InlinedCallSites) {
if (getInlineCandidate(&NewCandidate, CB))
CQueue.emplace(NewCandidate);
}
Changed = true;
}
}
} else if (CalledFunction && CalledFunction->getSubprogram() &&
!CalledFunction->isDeclaration()) {
SmallVector<CallBase *, 8> InlinedCallSites;
if (tryInlineCandidate(Candidate, &InlinedCallSites)) {
for (auto *CB : InlinedCallSites) {
if (getInlineCandidate(&NewCandidate, CB))
CQueue.emplace(NewCandidate);
}
Changed = true;
}
} else if (LTOPhase == ThinOrFullLTOPhase::ThinLTOPreLink) {
findCalleeFunctionSamples(*I)->findInlinedFunctions(
InlinedGUIDs, F.getParent(), PSI->getOrCompHotCountThreshold());
}
}
if (!CQueue.empty()) {
if (SizeLimit == (unsigned)ProfileInlineLimitMax)
++NumCSInlinedHitMaxLimit;
else if (SizeLimit == (unsigned)ProfileInlineLimitMin)
++NumCSInlinedHitMinLimit;
else
++NumCSInlinedHitGrowthLimit;
}
return Changed;
}
/// Find equivalence classes for the given block.
///
/// This finds all the blocks that are guaranteed to execute the same
/// number of times as \p BB1. To do this, it traverses all the
/// descendants of \p BB1 in the dominator or post-dominator tree.
///
/// A block BB2 will be in the same equivalence class as \p BB1 if
/// the following holds:
///
/// 1- \p BB1 is a descendant of BB2 in the opposite tree. So, if BB2
/// is a descendant of \p BB1 in the dominator tree, then BB2 should
/// dominate BB1 in the post-dominator tree.
///
/// 2- Both BB2 and \p BB1 must be in the same loop.
///
/// For every block BB2 that meets those two requirements, we set BB2's
/// equivalence class to \p BB1.
///
/// \param BB1 Block to check.
/// \param Descendants Descendants of \p BB1 in either the dom or pdom tree.
/// \param DomTree Opposite dominator tree. If \p Descendants is filled
/// with blocks from \p BB1's dominator tree, then
/// this is the post-dominator tree, and vice versa.
template <bool IsPostDom>
void SampleProfileLoader::findEquivalencesFor(
BasicBlock *BB1, ArrayRef<BasicBlock *> Descendants,
DominatorTreeBase<BasicBlock, IsPostDom> *DomTree) {
const BasicBlock *EC = EquivalenceClass[BB1];
uint64_t Weight = BlockWeights[EC];
for (const auto *BB2 : Descendants) {
bool IsDomParent = DomTree->dominates(BB2, BB1);
bool IsInSameLoop = LI->getLoopFor(BB1) == LI->getLoopFor(BB2);
if (BB1 != BB2 && IsDomParent && IsInSameLoop) {
EquivalenceClass[BB2] = EC;
// If BB2 is visited, then the entire EC should be marked as visited.
if (VisitedBlocks.count(BB2)) {
VisitedBlocks.insert(EC);
}
// If BB2 is heavier than BB1, make BB2 have the same weight
// as BB1.
//
// Note that we don't worry about the opposite situation here
// (when BB2 is lighter than BB1). We will deal with this
// during the propagation phase. Right now, we just want to
// make sure that BB1 has the largest weight of all the
// members of its equivalence set.
Weight = std::max(Weight, BlockWeights[BB2]);
}
}
if (EC == &EC->getParent()->getEntryBlock()) {
BlockWeights[EC] = Samples->getHeadSamples() + 1;
} else {
BlockWeights[EC] = Weight;
}
}
/// Find equivalence classes.
///
/// Since samples may be missing from blocks, we can fill in the gaps by setting
/// the weights of all the blocks in the same equivalence class to the same
/// weight. To compute the concept of equivalence, we use dominance and loop
/// information. Two blocks B1 and B2 are in the same equivalence class if B1
/// dominates B2, B2 post-dominates B1 and both are in the same loop.
///
/// \param F The function to query.
void SampleProfileLoader::findEquivalenceClasses(Function &F) {
SmallVector<BasicBlock *, 8> DominatedBBs;
LLVM_DEBUG(dbgs() << "\nBlock equivalence classes\n");
// Find equivalence sets based on dominance and post-dominance information.
for (auto &BB : F) {
BasicBlock *BB1 = &BB;
// Compute BB1's equivalence class once.
if (EquivalenceClass.count(BB1)) {
LLVM_DEBUG(printBlockEquivalence(dbgs(), BB1));
continue;
}
// By default, blocks are in their own equivalence class.
EquivalenceClass[BB1] = BB1;
// Traverse all the blocks dominated by BB1. We are looking for
// every basic block BB2 such that:
//
// 1- BB1 dominates BB2.
// 2- BB2 post-dominates BB1.
// 3- BB1 and BB2 are in the same loop nest.
//
// If all those conditions hold, it means that BB2 is executed
// as many times as BB1, so they are placed in the same equivalence
// class by making BB2's equivalence class be BB1.
DominatedBBs.clear();
DT->getDescendants(BB1, DominatedBBs);
findEquivalencesFor(BB1, DominatedBBs, PDT.get());
LLVM_DEBUG(printBlockEquivalence(dbgs(), BB1));
}
// Assign weights to equivalence classes.
//
// All the basic blocks in the same equivalence class will execute
// the same number of times. Since we know that the head block in
// each equivalence class has the largest weight, assign that weight
// to all the blocks in that equivalence class.
LLVM_DEBUG(
dbgs() << "\nAssign the same weight to all blocks in the same class\n");
for (auto &BI : F) {
const BasicBlock *BB = &BI;
const BasicBlock *EquivBB = EquivalenceClass[BB];
if (BB != EquivBB)
BlockWeights[BB] = BlockWeights[EquivBB];
LLVM_DEBUG(printBlockWeight(dbgs(), BB));
}
}
/// Visit the given edge to decide if it has a valid weight.
///
/// If \p E has not been visited before, we copy to \p UnknownEdge
/// and increment the count of unknown edges.
///
/// \param E Edge to visit.
/// \param NumUnknownEdges Current number of unknown edges.
/// \param UnknownEdge Set if E has not been visited before.
///
/// \returns E's weight, if known. Otherwise, return 0.
uint64_t SampleProfileLoader::visitEdge(Edge E, unsigned *NumUnknownEdges,
Edge *UnknownEdge) {
if (!VisitedEdges.count(E)) {
(*NumUnknownEdges)++;
*UnknownEdge = E;
return 0;
}
return EdgeWeights[E];
}
/// Propagate weights through incoming/outgoing edges.
///
/// If the weight of a basic block is known, and there is only one edge
/// with an unknown weight, we can calculate the weight of that edge.
///
/// Similarly, if all the edges have a known count, we can calculate the
/// count of the basic block, if needed.
///
/// \param F Function to process.
/// \param UpdateBlockCount Whether we should update basic block counts that
/// has already been annotated.
///
/// \returns True if new weights were assigned to edges or blocks.
bool SampleProfileLoader::propagateThroughEdges(Function &F,
bool UpdateBlockCount) {
bool Changed = false;
LLVM_DEBUG(dbgs() << "\nPropagation through edges\n");
for (const auto &BI : F) {
const BasicBlock *BB = &BI;
const BasicBlock *EC = EquivalenceClass[BB];
// Visit all the predecessor and successor edges to determine
// which ones have a weight assigned already. Note that it doesn't
// matter that we only keep track of a single unknown edge. The
// only case we are interested in handling is when only a single
// edge is unknown (see setEdgeOrBlockWeight).
for (unsigned i = 0; i < 2; i++) {
uint64_t TotalWeight = 0;
unsigned NumUnknownEdges = 0, NumTotalEdges = 0;
Edge UnknownEdge, SelfReferentialEdge, SingleEdge;
if (i == 0) {
// First, visit all predecessor edges.
NumTotalEdges = Predecessors[BB].size();
for (auto *Pred : Predecessors[BB]) {
Edge E = std::make_pair(Pred, BB);
TotalWeight += visitEdge(E, &NumUnknownEdges, &UnknownEdge);
if (E.first == E.second)
SelfReferentialEdge = E;
}
if (NumTotalEdges == 1) {
SingleEdge = std::make_pair(Predecessors[BB][0], BB);
}
} else {
// On the second round, visit all successor edges.
NumTotalEdges = Successors[BB].size();
for (auto *Succ : Successors[BB]) {
Edge E = std::make_pair(BB, Succ);
TotalWeight += visitEdge(E, &NumUnknownEdges, &UnknownEdge);
}
if (NumTotalEdges == 1) {
SingleEdge = std::make_pair(BB, Successors[BB][0]);
}
}
// After visiting all the edges, there are three cases that we
// can handle immediately:
//
// - All the edge weights are known (i.e., NumUnknownEdges == 0).
// In this case, we simply check that the sum of all the edges
// is the same as BB's weight. If not, we change BB's weight
// to match. Additionally, if BB had not been visited before,
// we mark it visited.
//
// - Only one edge is unknown and BB has already been visited.
// In this case, we can compute the weight of the edge by
// subtracting the total block weight from all the known
// edge weights. If the edges weight more than BB, then the
// edge of the last remaining edge is set to zero.
//
// - There exists a self-referential edge and the weight of BB is
// known. In this case, this edge can be based on BB's weight.
// We add up all the other known edges and set the weight on
// the self-referential edge as we did in the previous case.
//
// In any other case, we must continue iterating. Eventually,
// all edges will get a weight, or iteration will stop when
// it reaches SampleProfileMaxPropagateIterations.
if (NumUnknownEdges <= 1) {
uint64_t &BBWeight = BlockWeights[EC];
if (NumUnknownEdges == 0) {
if (!VisitedBlocks.count(EC)) {
// If we already know the weight of all edges, the weight of the
// basic block can be computed. It should be no larger than the sum
// of all edge weights.
if (TotalWeight > BBWeight) {
BBWeight = TotalWeight;
Changed = true;
LLVM_DEBUG(dbgs() << "All edge weights for " << BB->getName()
<< " known. Set weight for block: ";
printBlockWeight(dbgs(), BB););
}
} else if (NumTotalEdges == 1 &&
EdgeWeights[SingleEdge] < BlockWeights[EC]) {
// If there is only one edge for the visited basic block, use the
// block weight to adjust edge weight if edge weight is smaller.
EdgeWeights[SingleEdge] = BlockWeights[EC];
Changed = true;
}
} else if (NumUnknownEdges == 1 && VisitedBlocks.count(EC)) {
// If there is a single unknown edge and the block has been
// visited, then we can compute E's weight.
if (BBWeight >= TotalWeight)
EdgeWeights[UnknownEdge] = BBWeight - TotalWeight;
else
EdgeWeights[UnknownEdge] = 0;
const BasicBlock *OtherEC;
if (i == 0)
OtherEC = EquivalenceClass[UnknownEdge.first];
else
OtherEC = EquivalenceClass[UnknownEdge.second];
// Edge weights should never exceed the BB weights it connects.
if (VisitedBlocks.count(OtherEC) &&
EdgeWeights[UnknownEdge] > BlockWeights[OtherEC])
EdgeWeights[UnknownEdge] = BlockWeights[OtherEC];
VisitedEdges.insert(UnknownEdge);
Changed = true;
LLVM_DEBUG(dbgs() << "Set weight for edge: ";
printEdgeWeight(dbgs(), UnknownEdge));
}
} else if (VisitedBlocks.count(EC) && BlockWeights[EC] == 0) {
// If a block Weights 0, all its in/out edges should weight 0.
if (i == 0) {
for (auto *Pred : Predecessors[BB]) {
Edge E = std::make_pair(Pred, BB);
EdgeWeights[E] = 0;
VisitedEdges.insert(E);
}
} else {
for (auto *Succ : Successors[BB]) {
Edge E = std::make_pair(BB, Succ);
EdgeWeights[E] = 0;
VisitedEdges.insert(E);
}
}
} else if (SelfReferentialEdge.first && VisitedBlocks.count(EC)) {
uint64_t &BBWeight = BlockWeights[BB];
// We have a self-referential edge and the weight of BB is known.
if (BBWeight >= TotalWeight)
EdgeWeights[SelfReferentialEdge] = BBWeight - TotalWeight;
else
EdgeWeights[SelfReferentialEdge] = 0;
VisitedEdges.insert(SelfReferentialEdge);
Changed = true;
LLVM_DEBUG(dbgs() << "Set self-referential edge weight to: ";
printEdgeWeight(dbgs(), SelfReferentialEdge));
}
if (UpdateBlockCount && !VisitedBlocks.count(EC) && TotalWeight > 0) {
BlockWeights[EC] = TotalWeight;
VisitedBlocks.insert(EC);
Changed = true;
}
}
}
return Changed;
}
/// Build in/out edge lists for each basic block in the CFG.
///
/// We are interested in unique edges. If a block B1 has multiple
/// edges to another block B2, we only add a single B1->B2 edge.
void SampleProfileLoader::buildEdges(Function &F) {
for (auto &BI : F) {
BasicBlock *B1 = &BI;
// Add predecessors for B1.
SmallPtrSet<BasicBlock *, 16> Visited;
if (!Predecessors[B1].empty())
llvm_unreachable("Found a stale predecessors list in a basic block.");
for (pred_iterator PI = pred_begin(B1), PE = pred_end(B1); PI != PE; ++PI) {
BasicBlock *B2 = *PI;
if (Visited.insert(B2).second)
Predecessors[B1].push_back(B2);
}
// Add successors for B1.
Visited.clear();
if (!Successors[B1].empty())
llvm_unreachable("Found a stale successors list in a basic block.");
for (succ_iterator SI = succ_begin(B1), SE = succ_end(B1); SI != SE; ++SI) {
BasicBlock *B2 = *SI;
if (Visited.insert(B2).second)
Successors[B1].push_back(B2);
}
}
}
/// Returns the sorted CallTargetMap \p M by count in descending order.
static SmallVector<InstrProfValueData, 2> GetSortedValueDataFromCallTargets(
const SampleRecord::CallTargetMap & M) {
SmallVector<InstrProfValueData, 2> R;
for (const auto &I : SampleRecord::SortCallTargets(M)) {
R.emplace_back(InstrProfValueData{FunctionSamples::getGUID(I.first), I.second});
}
return R;
}
/// Propagate weights into edges
///
/// The following rules are applied to every block BB in the CFG:
///
/// - If BB has a single predecessor/successor, then the weight
/// of that edge is the weight of the block.
///
/// - If all incoming or outgoing edges are known except one, and the
/// weight of the block is already known, the weight of the unknown
/// edge will be the weight of the block minus the sum of all the known
/// edges. If the sum of all the known edges is larger than BB's weight,
/// we set the unknown edge weight to zero.
///
/// - If there is a self-referential edge, and the weight of the block is
/// known, the weight for that edge is set to the weight of the block
/// minus the weight of the other incoming edges to that block (if
/// known).
void SampleProfileLoader::propagateWeights(Function &F) {
bool Changed = true;
unsigned I = 0;
// If BB weight is larger than its corresponding loop's header BB weight,
// use the BB weight to replace the loop header BB weight.
for (auto &BI : F) {
BasicBlock *BB = &BI;
Loop *L = LI->getLoopFor(BB);
if (!L) {
continue;
}
BasicBlock *Header = L->getHeader();
if (Header && BlockWeights[BB] > BlockWeights[Header]) {
BlockWeights[Header] = BlockWeights[BB];
}
}
// Before propagation starts, build, for each block, a list of
// unique predecessors and successors. This is necessary to handle
// identical edges in multiway branches. Since we visit all blocks and all
// edges of the CFG, it is cleaner to build these lists once at the start
// of the pass.
buildEdges(F);
// Propagate until we converge or we go past the iteration limit.
while (Changed && I++ < SampleProfileMaxPropagateIterations) {
Changed = propagateThroughEdges(F, false);
}
// The first propagation propagates BB counts from annotated BBs to unknown
// BBs. The 2nd propagation pass resets edges weights, and use all BB weights
// to propagate edge weights.
VisitedEdges.clear();
Changed = true;
while (Changed && I++ < SampleProfileMaxPropagateIterations) {
Changed = propagateThroughEdges(F, false);
}
// The 3rd propagation pass allows adjust annotated BB weights that are
// obviously wrong.
Changed = true;
while (Changed && I++ < SampleProfileMaxPropagateIterations) {
Changed = propagateThroughEdges(F, true);
}
// Generate MD_prof metadata for every branch instruction using the
// edge weights computed during propagation.
LLVM_DEBUG(dbgs() << "\nPropagation complete. Setting branch weights\n");
LLVMContext &Ctx = F.getContext();
MDBuilder MDB(Ctx);
for (auto &BI : F) {
BasicBlock *BB = &BI;
if (BlockWeights[BB]) {
for (auto &I : BB->getInstList()) {
if (!isa<CallInst>(I) && !isa<InvokeInst>(I))
continue;
if (!cast<CallBase>(I).getCalledFunction()) {
const DebugLoc &DLoc = I.getDebugLoc();
if (!DLoc)
continue;
const DILocation *DIL = DLoc;
const FunctionSamples *FS = findFunctionSamples(I);
if (!FS)
continue;
auto CallSite = FunctionSamples::getCallSiteIdentifier(DIL);
auto T = FS->findCallTargetMapAt(CallSite);
if (!T || T.get().empty())
continue;
// Prorate the callsite counts to reflect what is already done to the
// callsite, such as ICP or calliste cloning.
if (FunctionSamples::ProfileIsProbeBased) {
if (Optional<PseudoProbe> Probe = extractProbe(I)) {
if (Probe->Factor < 1)
T = SampleRecord::adjustCallTargets(T.get(), Probe->Factor);
}
}
SmallVector<InstrProfValueData, 2> SortedCallTargets =
GetSortedValueDataFromCallTargets(T.get());
uint64_t Sum;
findIndirectCallFunctionSamples(I, Sum);
annotateValueSite(*I.getParent()->getParent()->getParent(), I,
SortedCallTargets, Sum, IPVK_IndirectCallTarget,
SortedCallTargets.size());
} else if (!isa<IntrinsicInst>(&I)) {
I.setMetadata(LLVMContext::MD_prof,
MDB.createBranchWeights(
{static_cast<uint32_t>(BlockWeights[BB])}));
}
}
}
Instruction *TI = BB->getTerminator();
if (TI->getNumSuccessors() == 1)
continue;
if (!isa<BranchInst>(TI) && !isa<SwitchInst>(TI))
continue;
DebugLoc BranchLoc = TI->getDebugLoc();
LLVM_DEBUG(dbgs() << "\nGetting weights for branch at line "
<< ((BranchLoc) ? Twine(BranchLoc.getLine())
: Twine("<UNKNOWN LOCATION>"))
<< ".\n");
SmallVector<uint32_t, 4> Weights;
uint32_t MaxWeight = 0;
Instruction *MaxDestInst;
for (unsigned I = 0; I < TI->getNumSuccessors(); ++I) {
BasicBlock *Succ = TI->getSuccessor(I);
Edge E = std::make_pair(BB, Succ);
uint64_t Weight = EdgeWeights[E];
LLVM_DEBUG(dbgs() << "\t"; printEdgeWeight(dbgs(), E));
// Use uint32_t saturated arithmetic to adjust the incoming weights,
// if needed. Sample counts in profiles are 64-bit unsigned values,
// but internally branch weights are expressed as 32-bit values.
if (Weight > std::numeric_limits<uint32_t>::max()) {
LLVM_DEBUG(dbgs() << " (saturated due to uint32_t overflow)");
Weight = std::numeric_limits<uint32_t>::max();
}
// Weight is added by one to avoid propagation errors introduced by
// 0 weights.
Weights.push_back(static_cast<uint32_t>(Weight + 1));
if (Weight != 0) {
if (Weight > MaxWeight) {
MaxWeight = Weight;
MaxDestInst = Succ->getFirstNonPHIOrDbgOrLifetime();
}
}
}
uint64_t TempWeight;
// Only set weights if there is at least one non-zero weight.
// In any other case, let the analyzer set weights.
// Do not set weights if the weights are present. In ThinLTO, the profile
// annotation is done twice. If the first annotation already set the
// weights, the second pass does not need to set it.
if (MaxWeight > 0 && !TI->extractProfTotalWeight(TempWeight)) {
LLVM_DEBUG(dbgs() << "SUCCESS. Found non-zero weights.\n");
TI->setMetadata(LLVMContext::MD_prof,
MDB.createBranchWeights(Weights));
ORE->emit([&]() {
return OptimizationRemark(DEBUG_TYPE, "PopularDest", MaxDestInst)
<< "most popular destination for conditional branches at "
<< ore::NV("CondBranchesLoc", BranchLoc);
});
} else {
LLVM_DEBUG(dbgs() << "SKIPPED. All branch weights are zero.\n");
}
}
}
/// Get the line number for the function header.
///
/// This looks up function \p F in the current compilation unit and
/// retrieves the line number where the function is defined. This is
/// line 0 for all the samples read from the profile file. Every line
/// number is relative to this line.
///
/// \param F Function object to query.
///
/// \returns the line number where \p F is defined. If it returns 0,
/// it means that there is no debug information available for \p F.
unsigned SampleProfileLoader::getFunctionLoc(Function &F) {
if (DISubprogram *S = F.getSubprogram())
return S->getLine();
if (NoWarnSampleUnused)
return 0;
// If the start of \p F is missing, emit a diagnostic to inform the user
// about the missed opportunity.
F.getContext().diagnose(DiagnosticInfoSampleProfile(
"No debug information found in function " + F.getName() +
": Function profile not used",
DS_Warning));
return 0;
}
void SampleProfileLoader::computeDominanceAndLoopInfo(Function &F) {
DT.reset(new DominatorTree);
DT->recalculate(F);
PDT.reset(new PostDominatorTree(F));
LI.reset(new LoopInfo);
LI->analyze(*DT);
}
/// Generate branch weight metadata for all branches in \p F.
///
/// Branch weights are computed out of instruction samples using a
/// propagation heuristic. Propagation proceeds in 3 phases:
///
/// 1- Assignment of block weights. All the basic blocks in the function
/// are initial assigned the same weight as their most frequently
/// executed instruction.
///
/// 2- Creation of equivalence classes. Since samples may be missing from
/// blocks, we can fill in the gaps by setting the weights of all the
/// blocks in the same equivalence class to the same weight. To compute
/// the concept of equivalence, we use dominance and loop information.
/// Two blocks B1 and B2 are in the same equivalence class if B1
/// dominates B2, B2 post-dominates B1 and both are in the same loop.
///
/// 3- Propagation of block weights into edges. This uses a simple
/// propagation heuristic. The following rules are applied to every
/// block BB in the CFG:
///
/// - If BB has a single predecessor/successor, then the weight
/// of that edge is the weight of the block.
///
/// - If all the edges are known except one, and the weight of the
/// block is already known, the weight of the unknown edge will
/// be the weight of the block minus the sum of all the known
/// edges. If the sum of all the known edges is larger than BB's weight,
/// we set the unknown edge weight to zero.
///
/// - If there is a self-referential edge, and the weight of the block is
/// known, the weight for that edge is set to the weight of the block
/// minus the weight of the other incoming edges to that block (if
/// known).
///
/// Since this propagation is not guaranteed to finalize for every CFG, we
/// only allow it to proceed for a limited number of iterations (controlled
/// by -sample-profile-max-propagate-iterations).
///
/// FIXME: Try to replace this propagation heuristic with a scheme
/// that is guaranteed to finalize. A work-list approach similar to
/// the standard value propagation algorithm used by SSA-CCP might
/// work here.
///
/// Once all the branch weights are computed, we emit the MD_prof
/// metadata on BB using the computed values for each of its branches.
///
/// \param F The function to query.
///
/// \returns true if \p F was modified. Returns false, otherwise.
bool SampleProfileLoader::emitAnnotations(Function &F) {
bool Changed = false;
if (FunctionSamples::ProfileIsProbeBased) {
if (!ProbeManager->profileIsValid(F, *Samples)) {
LLVM_DEBUG(
dbgs() << "Profile is invalid due to CFG mismatch for Function "
<< F.getName());
++NumMismatchedProfile;
return false;
}
++NumMatchedProfile;
} else {
if (getFunctionLoc(F) == 0)
return false;
LLVM_DEBUG(dbgs() << "Line number for the first instruction in "
<< F.getName() << ": " << getFunctionLoc(F) << "\n");
}
DenseSet<GlobalValue::GUID> InlinedGUIDs;
if (ProfileIsCS && CallsitePrioritizedInline)
Changed |= inlineHotFunctionsWithPriority(F, InlinedGUIDs);
else
Changed |= inlineHotFunctions(F, InlinedGUIDs);
// Compute basic block weights.
Changed |= computeBlockWeights(F);
if (Changed) {
// Add an entry count to the function using the samples gathered at the
// function entry.
// Sets the GUIDs that are inlined in the profiled binary. This is used
// for ThinLink to make correct liveness analysis, and also make the IR
// match the profiled binary before annotation.
F.setEntryCount(
ProfileCount(Samples->getHeadSamples() + 1, Function::PCT_Real),
&InlinedGUIDs);
// Compute dominance and loop info needed for propagation.
computeDominanceAndLoopInfo(F);
// Find equivalence classes.
findEquivalenceClasses(F);
// Propagate weights to all edges.
propagateWeights(F);
}
// If coverage checking was requested, compute it now.
if (SampleProfileRecordCoverage) {
unsigned Used = CoverageTracker.countUsedRecords(Samples, PSI);
unsigned Total = CoverageTracker.countBodyRecords(Samples, PSI);
unsigned Coverage = CoverageTracker.computeCoverage(Used, Total);
if (Coverage < SampleProfileRecordCoverage) {
F.getContext().diagnose(DiagnosticInfoSampleProfile(
F.getSubprogram()->getFilename(), getFunctionLoc(F),
Twine(Used) + " of " + Twine(Total) + " available profile records (" +
Twine(Coverage) + "%) were applied",
DS_Warning));
}
}
if (SampleProfileSampleCoverage) {
uint64_t Used = CoverageTracker.getTotalUsedSamples();
uint64_t Total = CoverageTracker.countBodySamples(Samples, PSI);
unsigned Coverage = CoverageTracker.computeCoverage(Used, Total);
if (Coverage < SampleProfileSampleCoverage) {
F.getContext().diagnose(DiagnosticInfoSampleProfile(
F.getSubprogram()->getFilename(), getFunctionLoc(F),
Twine(Used) + " of " + Twine(Total) + " available profile samples (" +
Twine(Coverage) + "%) were applied",
DS_Warning));
}
}
return Changed;
}
char SampleProfileLoaderLegacyPass::ID = 0;
INITIALIZE_PASS_BEGIN(SampleProfileLoaderLegacyPass, "sample-profile",
"Sample Profile loader", false, false)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
INITIALIZE_PASS_END(SampleProfileLoaderLegacyPass, "sample-profile",
"Sample Profile loader", false, false)
// Add inlined profile call edges to the call graph.
void SampleProfileLoader::addCallGraphEdges(CallGraph &CG,
const FunctionSamples &Samples) {
Function *Caller = SymbolMap.lookup(Samples.getFuncName());
if (!Caller || Caller->isDeclaration())
return;
// Skip non-inlined call edges which are not important since top down inlining
// for non-CS profile is to get more precise profile matching, not to enable
// more inlining.
for (const auto &CallsiteSamples : Samples.getCallsiteSamples()) {
for (const auto &InlinedSamples : CallsiteSamples.second) {
Function *Callee = SymbolMap.lookup(InlinedSamples.first);
if (Callee && !Callee->isDeclaration())
CG[Caller]->addCalledFunction(nullptr, CG[Callee]);
addCallGraphEdges(CG, InlinedSamples.second);
}
}
}
// Replace call graph edges with dynamic call edges from the profile.
void SampleProfileLoader::replaceCallGraphEdges(
CallGraph &CG, StringMap<Function *> &SymbolMap) {
// Remove static call edges from the call graph except for the ones from the
// root which make the call graph connected.
for (const auto &Node : CG)
if (Node.second.get() != CG.getExternalCallingNode())
Node.second->removeAllCalledFunctions();
// Add profile call edges to the call graph.
if (ProfileIsCS) {
ContextTracker->addCallGraphEdges(CG, SymbolMap);
} else {
for (const auto &Samples : Reader->getProfiles())
addCallGraphEdges(CG, Samples.second);
}
}
std::vector<Function *>
SampleProfileLoader::buildFunctionOrder(Module &M, CallGraph *CG) {
std::vector<Function *> FunctionOrderList;
FunctionOrderList.reserve(M.size());
if (!ProfileTopDownLoad || CG == nullptr) {
if (ProfileMergeInlinee) {
// Disable ProfileMergeInlinee if profile is not loaded in top down order,
// because the profile for a function may be used for the profile
// annotation of its outline copy before the profile merging of its
// non-inlined inline instances, and that is not the way how
// ProfileMergeInlinee is supposed to work.
ProfileMergeInlinee = false;
}
for (Function &F : M)
if (!F.isDeclaration() && F.hasFnAttribute("use-sample-profile"))
FunctionOrderList.push_back(&F);
return FunctionOrderList;
}
assert(&CG->getModule() == &M);
// Add indirect call edges from profile to augment the static call graph.
// Functions will be processed in a top-down order defined by the static call
// graph. Adjusting the order by considering indirect call edges from the
// profile (which don't exist in the static call graph) can enable the
// inlining of indirect call targets by processing the caller before them.
// TODO: enable this for non-CS profile and fix the counts returning logic to
// have a full support for indirect calls.
if (UseProfileIndirectCallEdges && ProfileIsCS) {
for (auto &Entry : *CG) {
const auto *F = Entry.first;
if (!F || F->isDeclaration() || !F->hasFnAttribute("use-sample-profile"))
continue;
auto &AllContexts = ContextTracker->getAllContextSamplesFor(F->getName());
if (AllContexts.empty())
continue;
for (const auto &BB : *F) {
for (const auto &I : BB.getInstList()) {
const auto *CB = dyn_cast<CallBase>(&I);
if (!CB || !CB->isIndirectCall())
continue;
const DebugLoc &DLoc = I.getDebugLoc();
if (!DLoc)
continue;
auto CallSite = FunctionSamples::getCallSiteIdentifier(DLoc);
for (FunctionSamples *Samples : AllContexts) {
if (auto CallTargets = Samples->findCallTargetMapAt(CallSite)) {
for (const auto &Target : CallTargets.get()) {
Function *Callee = SymbolMap.lookup(Target.first());
if (Callee && !Callee->isDeclaration())
Entry.second->addCalledFunction(nullptr, (*CG)[Callee]);
}
}
}
}
}
}
}
// Compute a top-down order the profile which is used to sort functions in
// one SCC later. The static processing order computed for an SCC may not
// reflect the call contexts in the context-sensitive profile, thus may cause
// potential inlining to be overlooked. The function order in one SCC is being
// adjusted to a top-down order based on the profile to favor more inlining.
DenseMap<Function *, uint64_t> ProfileOrderMap;
if (UseProfileTopDownOrder ||
(ProfileIsCS && !UseProfileTopDownOrder.getNumOccurrences())) {
// Create a static call graph. The call edges are not important since they
// will be replaced by dynamic edges from the profile.
CallGraph ProfileCG(M);
replaceCallGraphEdges(ProfileCG, SymbolMap);
scc_iterator<CallGraph *> CGI = scc_begin(&ProfileCG);
uint64_t I = 0;
while (!CGI.isAtEnd()) {
for (CallGraphNode *Node : *CGI) {
if (auto *F = Node->getFunction())
ProfileOrderMap[F] = ++I;
}
++CGI;
}
}
scc_iterator<CallGraph *> CGI = scc_begin(CG);
while (!CGI.isAtEnd()) {
uint64_t Start = FunctionOrderList.size();
for (CallGraphNode *Node : *CGI) {
auto *F = Node->getFunction();
if (F && !F->isDeclaration() && F->hasFnAttribute("use-sample-profile"))
FunctionOrderList.push_back(F);
}
// Sort nodes in SCC based on the profile top-down order.
if (!ProfileOrderMap.empty()) {
std::stable_sort(FunctionOrderList.begin() + Start,
FunctionOrderList.end(),
[&ProfileOrderMap](Function *Left, Function *Right) {
return ProfileOrderMap[Left] < ProfileOrderMap[Right];
});
}
++CGI;
}
LLVM_DEBUG({
dbgs() << "Function processing order:\n";
for (auto F : reverse(FunctionOrderList)) {
dbgs() << F->getName() << "\n";
}
});
std::reverse(FunctionOrderList.begin(), FunctionOrderList.end());
return FunctionOrderList;
}
bool SampleProfileLoader::doInitialization(Module &M,
FunctionAnalysisManager *FAM) {
auto &Ctx = M.getContext();
auto ReaderOrErr =
SampleProfileReader::create(Filename, Ctx, RemappingFilename);
if (std::error_code EC = ReaderOrErr.getError()) {
std::string Msg = "Could not open profile: " + EC.message();
Ctx.diagnose(DiagnosticInfoSampleProfile(Filename, Msg));
return false;
}
Reader = std::move(ReaderOrErr.get());
Reader->setSkipFlatProf(LTOPhase == ThinOrFullLTOPhase::ThinLTOPostLink);
Reader->collectFuncsFrom(M);
if (std::error_code EC = Reader->read()) {
std::string Msg = "profile reading failed: " + EC.message();
Ctx.diagnose(DiagnosticInfoSampleProfile(Filename, Msg));
return false;
}
PSL = Reader->getProfileSymbolList();
// While profile-sample-accurate is on, ignore symbol list.
ProfAccForSymsInList =
ProfileAccurateForSymsInList && PSL && !ProfileSampleAccurate;
if (ProfAccForSymsInList) {
NamesInProfile.clear();
if (auto NameTable = Reader->getNameTable())
NamesInProfile.insert(NameTable->begin(), NameTable->end());
}
if (FAM && !ProfileInlineReplayFile.empty()) {
ExternalInlineAdvisor = std::make_unique<ReplayInlineAdvisor>(
M, *FAM, Ctx, /*OriginalAdvisor=*/nullptr, ProfileInlineReplayFile,
/*EmitRemarks=*/false);
if (!ExternalInlineAdvisor->areReplayRemarksLoaded())
ExternalInlineAdvisor.reset();
}
// Apply tweaks if context-sensitive profile is available.
if (Reader->profileIsCS()) {
ProfileIsCS = true;
FunctionSamples::ProfileIsCS = true;
// Enable priority-base inliner and size inline by default for CSSPGO.
if (!ProfileSizeInline.getNumOccurrences())
ProfileSizeInline = true;
if (!CallsitePrioritizedInline.getNumOccurrences())
CallsitePrioritizedInline = true;
// Tracker for profiles under different context
ContextTracker =
std::make_unique<SampleContextTracker>(Reader->getProfiles());
}
// Load pseudo probe descriptors for probe-based function samples.
if (Reader->profileIsProbeBased()) {
ProbeManager = std::make_unique<PseudoProbeManager>(M);
if (!ProbeManager->moduleIsProbed(M)) {
const char *Msg =
"Pseudo-probe-based profile requires SampleProfileProbePass";
Ctx.diagnose(DiagnosticInfoSampleProfile(Filename, Msg));
return false;
}
}
return true;
}
ModulePass *llvm::createSampleProfileLoaderPass() {
return new SampleProfileLoaderLegacyPass();
}
ModulePass *llvm::createSampleProfileLoaderPass(StringRef Name) {
return new SampleProfileLoaderLegacyPass(Name);
}
bool SampleProfileLoader::runOnModule(Module &M, ModuleAnalysisManager *AM,
ProfileSummaryInfo *_PSI, CallGraph *CG) {
GUIDToFuncNameMapper Mapper(M, *Reader, GUIDToFuncNameMap);
PSI = _PSI;
if (M.getProfileSummary(/* IsCS */ false) == nullptr) {
M.setProfileSummary(Reader->getSummary().getMD(M.getContext()),
ProfileSummary::PSK_Sample);
PSI->refresh();
}
// Compute the total number of samples collected in this profile.
for (const auto &I : Reader->getProfiles())
TotalCollectedSamples += I.second.getTotalSamples();
auto Remapper = Reader->getRemapper();
// Populate the symbol map.
for (const auto &N_F : M.getValueSymbolTable()) {
StringRef OrigName = N_F.getKey();
Function *F = dyn_cast<Function>(N_F.getValue());
if (F == nullptr)
continue;
SymbolMap[OrigName] = F;
auto pos = OrigName.find('.');
if (pos != StringRef::npos) {
StringRef NewName = OrigName.substr(0, pos);
auto r = SymbolMap.insert(std::make_pair(NewName, F));
// Failiing to insert means there is already an entry in SymbolMap,
// thus there are multiple functions that are mapped to the same
// stripped name. In this case of name conflicting, set the value
// to nullptr to avoid confusion.
if (!r.second)
r.first->second = nullptr;
OrigName = NewName;
}
// Insert the remapped names into SymbolMap.
if (Remapper) {
if (auto MapName = Remapper->lookUpNameInProfile(OrigName)) {
if (*MapName == OrigName)
continue;
SymbolMap.insert(std::make_pair(*MapName, F));
}
}
}
bool retval = false;
for (auto F : buildFunctionOrder(M, CG)) {
assert(!F->isDeclaration());
clearFunctionData();
retval |= runOnFunction(*F, AM);
}
// Account for cold calls not inlined....
if (!ProfileIsCS)
for (const std::pair<Function *, NotInlinedProfileInfo> &pair :
notInlinedCallInfo)
updateProfileCallee(pair.first, pair.second.entryCount);
return retval;
}
bool SampleProfileLoaderLegacyPass::runOnModule(Module &M) {
ACT = &getAnalysis<AssumptionCacheTracker>();
TTIWP = &getAnalysis<TargetTransformInfoWrapperPass>();
TLIWP = &getAnalysis<TargetLibraryInfoWrapperPass>();
ProfileSummaryInfo *PSI =
&getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
return SampleLoader.runOnModule(M, nullptr, PSI, nullptr);
}
bool SampleProfileLoader::runOnFunction(Function &F, ModuleAnalysisManager *AM) {
LLVM_DEBUG(dbgs() << "\n\nProcessing Function " << F.getName() << "\n");
DILocation2SampleMap.clear();
// By default the entry count is initialized to -1, which will be treated
// conservatively by getEntryCount as the same as unknown (None). This is
// to avoid newly added code to be treated as cold. If we have samples
// this will be overwritten in emitAnnotations.
uint64_t initialEntryCount = -1;
ProfAccForSymsInList = ProfileAccurateForSymsInList && PSL;
if (ProfileSampleAccurate || F.hasFnAttribute("profile-sample-accurate")) {
// initialize all the function entry counts to 0. It means all the
// functions without profile will be regarded as cold.
initialEntryCount = 0;
// profile-sample-accurate is a user assertion which has a higher precedence
// than symbol list. When profile-sample-accurate is on, ignore symbol list.
ProfAccForSymsInList = false;
}
// PSL -- profile symbol list include all the symbols in sampled binary.
// If ProfileAccurateForSymsInList is enabled, PSL is used to treat
// old functions without samples being cold, without having to worry
// about new and hot functions being mistakenly treated as cold.
if (ProfAccForSymsInList) {
// Initialize the entry count to 0 for functions in the list.
if (PSL->contains(F.getName()))
initialEntryCount = 0;
// Function in the symbol list but without sample will be regarded as
// cold. To minimize the potential negative performance impact it could
// have, we want to be a little conservative here saying if a function
// shows up in the profile, no matter as outline function, inline instance
// or call targets, treat the function as not being cold. This will handle
// the cases such as most callsites of a function are inlined in sampled
// binary but not inlined in current build (because of source code drift,
// imprecise debug information, or the callsites are all cold individually
// but not cold accumulatively...), so the outline function showing up as
// cold in sampled binary will actually not be cold after current build.
StringRef CanonName = FunctionSamples::getCanonicalFnName(F);
if (NamesInProfile.count(CanonName))
initialEntryCount = -1;
}
// Initialize entry count when the function has no existing entry
// count value.
if (!F.getEntryCount().hasValue())
F.setEntryCount(ProfileCount(initialEntryCount, Function::PCT_Real));
std::unique_ptr<OptimizationRemarkEmitter> OwnedORE;
if (AM) {
auto &FAM =
AM->getResult<FunctionAnalysisManagerModuleProxy>(*F.getParent())
.getManager();
ORE = &FAM.getResult<OptimizationRemarkEmitterAnalysis>(F);
} else {
OwnedORE = std::make_unique<OptimizationRemarkEmitter>(&F);
ORE = OwnedORE.get();
}
if (ProfileIsCS)
Samples = ContextTracker->getBaseSamplesFor(F);
else
Samples = Reader->getSamplesFor(F);
if (Samples && !Samples->empty())
return emitAnnotations(F);
return false;
}
PreservedAnalyses SampleProfileLoaderPass::run(Module &M,
ModuleAnalysisManager &AM) {
FunctionAnalysisManager &FAM =
AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
auto GetAssumptionCache = [&](Function &F) -> AssumptionCache & {
return FAM.getResult<AssumptionAnalysis>(F);
};
auto GetTTI = [&](Function &F) -> TargetTransformInfo & {
return FAM.getResult<TargetIRAnalysis>(F);
};
auto GetTLI = [&](Function &F) -> const TargetLibraryInfo & {
return FAM.getResult<TargetLibraryAnalysis>(F);
};
SampleProfileLoader SampleLoader(
ProfileFileName.empty() ? SampleProfileFile : ProfileFileName,
ProfileRemappingFileName.empty() ? SampleProfileRemappingFile
: ProfileRemappingFileName,
LTOPhase, GetAssumptionCache, GetTTI, GetTLI);
if (!SampleLoader.doInitialization(M, &FAM))
return PreservedAnalyses::all();
ProfileSummaryInfo *PSI = &AM.getResult<ProfileSummaryAnalysis>(M);
CallGraph &CG = AM.getResult<CallGraphAnalysis>(M);
if (!SampleLoader.runOnModule(M, &AM, PSI, &CG))
return PreservedAnalyses::all();
return PreservedAnalyses::none();
}
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