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llvm-mirror/tools/llvm-profgen/PerfReader.cpp
wlei 189f7cb2ab [llvm-profgen][NFC] Fix test failure by making unwinder's output deterministic
Don't know why under Sanitizer build(asan/msan/ubsan), the `std::unordered_map<string, ...>`'s output order is reversed, make the regression test failed.

This change creates a workaround by using sorted container to make the output deterministic.

Reviewed By: hoy, wenlei

Differential Revision: https://reviews.llvm.org/D92816
2020-12-07 22:36:25 -08:00

511 lines
18 KiB
C++

//===-- PerfReader.cpp - perfscript reader ---------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "PerfReader.h"
static cl::opt<bool> ShowMmapEvents("show-mmap-events", cl::ReallyHidden,
cl::init(false), cl::ZeroOrMore,
cl::desc("Print binary load events."));
static cl::opt<bool> ShowUnwinderOutput("show-unwinder-output",
cl::ReallyHidden, cl::init(false),
cl::ZeroOrMore,
cl::desc("Print unwinder output"));
namespace llvm {
namespace sampleprof {
void VirtualUnwinder::unwindCall(UnwindState &State) {
// The 2nd frame after leaf could be missing if stack sample is
// taken when IP is within prolog/epilog, as frame chain isn't
// setup yet. Fill in the missing frame in that case.
// TODO: Currently we just assume all the addr that can't match the
// 2nd frame is in prolog/epilog. In the future, we will switch to
// pro/epi tracker(Dwarf CFI) for the precise check.
uint64_t Source = State.getCurrentLBRSource();
auto Iter = State.CallStack.begin();
if (State.CallStack.size() == 1 || *(++Iter) != Source) {
State.CallStack.front() = Source;
} else {
State.CallStack.pop_front();
}
State.InstPtr.update(Source);
}
void VirtualUnwinder::unwindLinear(UnwindState &State, uint64_t Repeat) {
InstructionPointer &IP = State.InstPtr;
uint64_t Target = State.getCurrentLBRTarget();
uint64_t End = IP.Address;
// Unwind linear execution part
while (IP.Address >= Target) {
uint64_t PrevIP = IP.Address;
IP.backward();
// Break into segments for implicit call/return due to inlining
bool SameInlinee =
State.getBinary()->inlineContextEqual(PrevIP, IP.Address);
if (!SameInlinee || PrevIP == Target) {
recordRangeCount(PrevIP, End, State, Repeat);
End = IP.Address;
}
State.CallStack.front() = IP.Address;
}
}
void VirtualUnwinder::unwindReturn(UnwindState &State) {
// Add extra frame as we unwind through the return
const LBREntry &LBR = State.getCurrentLBR();
uint64_t CallAddr = State.getBinary()->getCallAddrFromFrameAddr(LBR.Target);
State.CallStack.front() = CallAddr;
State.CallStack.push_front(LBR.Source);
State.InstPtr.update(LBR.Source);
}
void VirtualUnwinder::unwindBranchWithinFrame(UnwindState &State) {
// TODO: Tolerate tail call for now, as we may see tail call from libraries.
// This is only for intra function branches, excluding tail calls.
uint64_t Source = State.getCurrentLBRSource();
State.CallStack.front() = Source;
State.InstPtr.update(Source);
}
void VirtualUnwinder::recordRangeCount(uint64_t Start, uint64_t End,
UnwindState &State, uint64_t Repeat) {
std::string &&ContextId = State.getExpandedContextStr();
uint64_t StartOffset = State.getBinary()->virtualAddrToOffset(Start);
uint64_t EndOffset = State.getBinary()->virtualAddrToOffset(End);
SampleCounters->recordRangeCount(ContextId, StartOffset, EndOffset, Repeat);
}
void VirtualUnwinder::recordBranchCount(const LBREntry &Branch,
UnwindState &State, uint64_t Repeat) {
if (Branch.IsArtificial)
return;
std::string &&ContextId = State.getExpandedContextStr();
uint64_t SourceOffset = State.getBinary()->virtualAddrToOffset(Branch.Source);
uint64_t TargetOffset = State.getBinary()->virtualAddrToOffset(Branch.Target);
SampleCounters->recordBranchCount(ContextId, SourceOffset, TargetOffset,
Repeat);
}
bool VirtualUnwinder::unwind(const HybridSample &Sample, uint64_t Repeat) {
// Capture initial state as starting point for unwinding.
UnwindState State(Sample);
// Sanity check - making sure leaf of LBR aligns with leaf of stack sample
// Stack sample sometimes can be unreliable, so filter out bogus ones.
if (!State.validateInitialState())
return false;
// Also do not attempt linear unwind for the leaf range as it's incomplete.
bool IsLeaf = true;
// Now process the LBR samples in parrallel with stack sample
// Note that we do not reverse the LBR entry order so we can
// unwind the sample stack as we walk through LBR entries.
while (State.hasNextLBR()) {
State.checkStateConsistency();
// Unwind implicit calls/returns from inlining, along the linear path,
// break into smaller sub section each with its own calling context.
if (!IsLeaf) {
unwindLinear(State, Repeat);
}
IsLeaf = false;
// Save the LBR branch before it gets unwound.
const LBREntry &Branch = State.getCurrentLBR();
if (isCallState(State)) {
// Unwind calls - we know we encountered call if LBR overlaps with
// transition between leaf the 2nd frame. Note that for calls that
// were not in the original stack sample, we should have added the
// extra frame when processing the return paired with this call.
unwindCall(State);
} else if (isReturnState(State)) {
// Unwind returns - check whether the IP is indeed at a return instruction
unwindReturn(State);
} else {
// Unwind branches - for regular intra function branches, we only
// need to record branch with context.
unwindBranchWithinFrame(State);
}
State.advanceLBR();
// Record `branch` with calling context after unwinding.
recordBranchCount(Branch, State, Repeat);
}
return true;
}
PerfReader::PerfReader(cl::list<std::string> &BinaryFilenames) {
// Load the binaries.
for (auto Filename : BinaryFilenames)
loadBinary(Filename, /*AllowNameConflict*/ false);
}
ProfiledBinary &PerfReader::loadBinary(const StringRef BinaryPath,
bool AllowNameConflict) {
// The binary table is currently indexed by the binary name not the full
// binary path. This is because the user-given path may not match the one
// that was actually executed.
StringRef BinaryName = llvm::sys::path::filename(BinaryPath);
// Call to load the binary in the ctor of ProfiledBinary.
auto Ret = BinaryTable.insert({BinaryName, ProfiledBinary(BinaryPath)});
if (!Ret.second && !AllowNameConflict) {
std::string ErrorMsg = "Binary name conflict: " + BinaryPath.str() +
" and " + Ret.first->second.getPath().str() + " \n";
exitWithError(ErrorMsg);
}
return Ret.first->second;
}
void PerfReader::updateBinaryAddress(const MMapEvent &Event) {
// Load the binary.
StringRef BinaryPath = Event.BinaryPath;
StringRef BinaryName = llvm::sys::path::filename(BinaryPath);
auto I = BinaryTable.find(BinaryName);
// Drop the event which doesn't belong to user-provided binaries
// or if its image is loaded at the same address
if (I == BinaryTable.end() || Event.BaseAddress == I->second.getBaseAddress())
return;
ProfiledBinary &Binary = I->second;
// A binary image could be uploaded and then reloaded at different
// place, so update the address map here
AddrToBinaryMap.erase(Binary.getBaseAddress());
AddrToBinaryMap[Event.BaseAddress] = &Binary;
// Update binary load address.
Binary.setBaseAddress(Event.BaseAddress);
}
ProfiledBinary *PerfReader::getBinary(uint64_t Address) {
auto Iter = AddrToBinaryMap.lower_bound(Address);
if (Iter == AddrToBinaryMap.end() || Iter->first != Address) {
if (Iter == AddrToBinaryMap.begin())
return nullptr;
Iter--;
}
return Iter->second;
}
static void printSampleCounter(ContextRangeCounter &Counter) {
// Use ordered map to make the output deterministic
std::map<std::string, RangeSample> OrderedCounter(Counter.begin(),
Counter.end());
for (auto Range : OrderedCounter) {
outs() << Range.first << "\n";
for (auto I : Range.second) {
outs() << " (" << format("%" PRIx64, I.first.first) << ", "
<< format("%" PRIx64, I.first.second) << "): " << I.second << "\n";
}
}
}
void PerfReader::printUnwinderOutput() {
for (auto I : BinarySampleCounters) {
const ProfiledBinary *Binary = I.first;
outs() << "Binary(" << Binary->getName().str() << ")'s Range Counter:\n";
printSampleCounter(I.second.RangeCounter);
outs() << "\nBinary(" << Binary->getName().str() << ")'s Branch Counter:\n";
printSampleCounter(I.second.BranchCounter);
}
}
void PerfReader::unwindSamples() {
for (const auto &Item : AggregatedSamples) {
const HybridSample &Sample = Item.first;
VirtualUnwinder Unwinder(&BinarySampleCounters[Sample.Binary]);
Unwinder.unwind(Sample, Item.second);
}
if (ShowUnwinderOutput)
printUnwinderOutput();
}
bool PerfReader::extractLBRStack(TraceStream &TraceIt,
SmallVector<LBREntry, 16> &LBRStack,
ProfiledBinary *Binary) {
// The raw format of LBR stack is like:
// 0x4005c8/0x4005dc/P/-/-/0 0x40062f/0x4005b0/P/-/-/0 ...
// ... 0x4005c8/0x4005dc/P/-/-/0
// It's in FIFO order and seperated by whitespace.
SmallVector<StringRef, 32> Records;
TraceIt.getCurrentLine().split(Records, " ");
// Extract leading instruction pointer if present, use single
// list to pass out as reference.
size_t Index = 0;
if (!Records.empty() && Records[0].find('/') == StringRef::npos) {
Index = 1;
}
// Now extract LBR samples - note that we do not reverse the
// LBR entry order so we can unwind the sample stack as we walk
// through LBR entries.
uint64_t PrevTrDst = 0;
while (Index < Records.size()) {
auto &Token = Records[Index++];
if (Token.size() == 0)
continue;
SmallVector<StringRef, 8> Addresses;
Token.split(Addresses, "/");
uint64_t Src;
uint64_t Dst;
Addresses[0].substr(2).getAsInteger(16, Src);
Addresses[1].substr(2).getAsInteger(16, Dst);
bool SrcIsInternal = Binary->addressIsCode(Src);
bool DstIsInternal = Binary->addressIsCode(Dst);
bool IsArtificial = false;
// Ignore branches outside the current binary.
if (!SrcIsInternal && !DstIsInternal)
continue;
if (!SrcIsInternal && DstIsInternal) {
// For transition from external code (such as dynamic libraries) to
// the current binary, keep track of the branch target which will be
// grouped with the Source of the last transition from the current
// binary.
PrevTrDst = Dst;
continue;
}
if (SrcIsInternal && !DstIsInternal) {
// For transition to external code, group the Source with the next
// availabe transition target.
if (!PrevTrDst)
continue;
Dst = PrevTrDst;
PrevTrDst = 0;
IsArtificial = true;
}
// TODO: filter out buggy duplicate branches on Skylake
LBRStack.emplace_back(LBREntry(Src, Dst, IsArtificial));
}
TraceIt.advance();
return !LBRStack.empty();
}
bool PerfReader::extractCallstack(TraceStream &TraceIt,
std::list<uint64_t> &CallStack) {
// The raw format of call stack is like:
// 4005dc # leaf frame
// 400634
// 400684 # root frame
// It's in bottom-up order with each frame in one line.
// Extract stack frames from sample
ProfiledBinary *Binary = nullptr;
while (!TraceIt.isAtEoF() && !TraceIt.getCurrentLine().startswith(" 0x")) {
StringRef FrameStr = TraceIt.getCurrentLine().ltrim();
// We might get an empty line at the beginning or comments, skip it
uint64_t FrameAddr = 0;
if (FrameStr.getAsInteger(16, FrameAddr)) {
TraceIt.advance();
break;
}
TraceIt.advance();
if (!Binary) {
Binary = getBinary(FrameAddr);
// we might have addr not match the MMAP, skip it
if (!Binary) {
if (AddrToBinaryMap.size() == 0)
WithColor::warning() << "No MMAP event in the perfscript, create it "
"with '--show-mmap-events'\n";
break;
}
}
// Currently intermixed frame from different binaries is not supported.
// Ignore bottom frames not from binary of interest.
if (!Binary->addressIsCode(FrameAddr))
break;
// We need to translate return address to call address
// for non-leaf frames
if (!CallStack.empty()) {
FrameAddr = Binary->getCallAddrFromFrameAddr(FrameAddr);
}
CallStack.emplace_back(FrameAddr);
}
if (CallStack.empty())
return false;
// Skip other unrelated line, find the next valid LBR line
while (!TraceIt.isAtEoF() && !TraceIt.getCurrentLine().startswith(" 0x")) {
TraceIt.advance();
}
// Filter out broken stack sample. We may not have complete frame info
// if sample end up in prolog/epilog, the result is dangling context not
// connected to entry point. This should be relatively rare thus not much
// impact on overall profile quality. However we do want to filter them
// out to reduce the number of different calling contexts. One instance
// of such case - when sample landed in prolog/epilog, somehow stack
// walking will be broken in an unexpected way that higher frames will be
// missing.
return !Binary->addressInPrologEpilog(CallStack.front());
}
void PerfReader::parseHybridSample(TraceStream &TraceIt) {
// The raw hybird sample started with call stack in FILO order and followed
// intermediately by LBR sample
// e.g.
// 4005dc # call stack leaf
// 400634
// 400684 # call stack root
// 0x4005c8/0x4005dc/P/-/-/0 0x40062f/0x4005b0/P/-/-/0 ...
// ... 0x4005c8/0x4005dc/P/-/-/0 # LBR Entries
//
HybridSample Sample;
// Parsing call stack and populate into HybridSample.CallStack
if (!extractCallstack(TraceIt, Sample.CallStack)) {
// Skip the next LBR line matched current call stack
if (!TraceIt.isAtEoF() && TraceIt.getCurrentLine().startswith(" 0x"))
TraceIt.advance();
return;
}
// Set the binary current sample belongs to
Sample.Binary = getBinary(Sample.CallStack.front());
if (!TraceIt.isAtEoF() && TraceIt.getCurrentLine().startswith(" 0x")) {
// Parsing LBR stack and populate into HybridSample.LBRStack
if (extractLBRStack(TraceIt, Sample.LBRStack, Sample.Binary)) {
// Canonicalize stack leaf to avoid 'random' IP from leaf frame skew LBR
// ranges
Sample.CallStack.front() = Sample.LBRStack[0].Target;
// Record samples by aggregation
AggregatedSamples[Sample]++;
}
} else {
// LBR sample is encoded in single line after stack sample
exitWithError("'Hybrid perf sample is corrupted, No LBR sample line");
}
}
void PerfReader::parseMMap2Event(TraceStream &TraceIt) {
// Parse a line like:
// PERF_RECORD_MMAP2 2113428/2113428: [0x7fd4efb57000(0x204000) @ 0
// 08:04 19532229 3585508847]: r-xp /usr/lib64/libdl-2.17.so
constexpr static const char *const Pattern =
"PERF_RECORD_MMAP2 ([0-9]+)/[0-9]+: "
"\\[(0x[a-f0-9]+)\\((0x[a-f0-9]+)\\) @ "
"(0x[a-f0-9]+|0) .*\\]: [-a-z]+ (.*)";
// Field 0 - whole line
// Field 1 - PID
// Field 2 - base address
// Field 3 - mmapped size
// Field 4 - page offset
// Field 5 - binary path
enum EventIndex {
WHOLE_LINE = 0,
PID = 1,
BASE_ADDRESS = 2,
MMAPPED_SIZE = 3,
PAGE_OFFSET = 4,
BINARY_PATH = 5
};
Regex RegMmap2(Pattern);
SmallVector<StringRef, 6> Fields;
bool R = RegMmap2.match(TraceIt.getCurrentLine(), &Fields);
if (!R) {
std::string ErrorMsg = "Cannot parse mmap event: Line" +
Twine(TraceIt.getLineNumber()).str() + ": " +
TraceIt.getCurrentLine().str() + " \n";
exitWithError(ErrorMsg);
}
MMapEvent Event;
Fields[PID].getAsInteger(10, Event.PID);
Fields[BASE_ADDRESS].getAsInteger(0, Event.BaseAddress);
Fields[MMAPPED_SIZE].getAsInteger(0, Event.Size);
Fields[PAGE_OFFSET].getAsInteger(0, Event.Offset);
Event.BinaryPath = Fields[BINARY_PATH];
updateBinaryAddress(Event);
if (ShowMmapEvents) {
outs() << "Mmap: Binary " << Event.BinaryPath << " loaded at "
<< format("0x%" PRIx64 ":", Event.BaseAddress) << " \n";
}
TraceIt.advance();
}
void PerfReader::parseEventOrSample(TraceStream &TraceIt) {
if (TraceIt.getCurrentLine().startswith("PERF_RECORD_MMAP2"))
parseMMap2Event(TraceIt);
else if (getPerfScriptType() == PERF_LBR_STACK)
parseHybridSample(TraceIt);
else {
// TODO: parse other type sample
TraceIt.advance();
}
}
void PerfReader::parseAndAggregateTrace(StringRef Filename) {
// Trace line iterator
TraceStream TraceIt(Filename);
while (!TraceIt.isAtEoF())
parseEventOrSample(TraceIt);
}
void PerfReader::checkAndSetPerfType(
cl::list<std::string> &PerfTraceFilenames) {
bool HasHybridPerf = true;
for (auto FileName : PerfTraceFilenames) {
if (!isHybridPerfScript(FileName)) {
HasHybridPerf = false;
break;
}
}
if (HasHybridPerf) {
// Set up ProfileIsCS to enable context-sensitive functionalities
// in SampleProf
FunctionSamples::ProfileIsCS = true;
PerfType = PERF_LBR_STACK;
} else {
// TODO: Support other type of perf script
PerfType = PERF_INVILID;
}
if (BinaryTable.size() > 1) {
// TODO: remove this if everything is ready to support multiple binaries.
exitWithError("Currently only support one input binary, multiple binaries' "
"profile will be merged in one profile and make profile "
"summary info inaccurate. Please use `perfdata` to merge "
"profiles from multiple binaries.");
}
}
void PerfReader::generateRawProfile() {
if (getPerfScriptType() == PERF_LBR_STACK) {
// Unwind samples if it's hybird sample
unwindSamples();
} else if (getPerfScriptType() == PERF_LBR) {
// TODO: range overlap computation for regular AutoFDO
}
}
void PerfReader::parsePerfTraces(cl::list<std::string> &PerfTraceFilenames) {
// Check and set current perfscript type
checkAndSetPerfType(PerfTraceFilenames);
// Parse perf traces and do aggregation.
for (auto Filename : PerfTraceFilenames)
parseAndAggregateTrace(Filename);
generateRawProfile();
}
} // end namespace sampleprof
} // end namespace llvm