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llvm-project/llvm/tools/llvm-xray/xray-graph.cpp

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//===-- xray-graph.cpp: XRay Function Call Graph Renderer -----------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Generate a DOT file to represent the function call graph encountered in
// the trace.
//
//===----------------------------------------------------------------------===//
#include "xray-graph.h"
#include "xray-registry.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/XRay/InstrumentationMap.h"
#include "llvm/XRay/Trace.h"
using namespace llvm;
using namespace llvm::xray;
// Setup llvm-xray graph subcommand and its options.
static cl::SubCommand GraphC("graph", "Generate function-call graph");
static cl::opt<std::string> GraphInput(cl::Positional,
cl::desc("<xray log file>"),
cl::Required, cl::sub(GraphC));
static cl::opt<bool>
GraphKeepGoing("keep-going", cl::desc("Keep going on errors encountered"),
cl::sub(GraphC), cl::init(false));
static cl::alias GraphKeepGoing2("k", cl::aliasopt(GraphKeepGoing),
cl::desc("Alias for -keep-going"));
static cl::opt<std::string>
GraphOutput("output", cl::value_desc("Output file"), cl::init("-"),
cl::desc("output file; use '-' for stdout"), cl::sub(GraphC));
static cl::alias GraphOutput2("o", cl::aliasopt(GraphOutput),
cl::desc("Alias for -output"));
static cl::opt<std::string>
GraphInstrMap("instr_map",
cl::desc("binary with the instrumrntation map, or "
"a separate instrumentation map"),
cl::value_desc("binary with xray_instr_map"), cl::sub(GraphC),
cl::init(""));
static cl::alias GraphInstrMap2("m", cl::aliasopt(GraphInstrMap),
cl::desc("alias for -instr_map"));
static cl::opt<bool> GraphDeduceSiblingCalls(
"deduce-sibling-calls",
cl::desc("Deduce sibling calls when unrolling function call stacks"),
cl::sub(GraphC), cl::init(false));
static cl::alias
GraphDeduceSiblingCalls2("d", cl::aliasopt(GraphDeduceSiblingCalls),
cl::desc("Alias for -deduce-sibling-calls"));
static cl::opt<GraphRenderer::StatType>
GraphEdgeLabel("edge-label",
cl::desc("Output graphs with edges labeled with this field"),
cl::value_desc("field"), cl::sub(GraphC),
cl::init(GraphRenderer::StatType::NONE),
cl::values(clEnumValN(GraphRenderer::StatType::NONE, "none",
"Do not label Edges"),
clEnumValN(GraphRenderer::StatType::COUNT,
"count", "function call counts"),
clEnumValN(GraphRenderer::StatType::MIN, "min",
"minimum function durations"),
clEnumValN(GraphRenderer::StatType::MED, "med",
"median function durations"),
clEnumValN(GraphRenderer::StatType::PCT90, "90p",
"90th percentile durations"),
clEnumValN(GraphRenderer::StatType::PCT99, "99p",
"99th percentile durations"),
clEnumValN(GraphRenderer::StatType::MAX, "max",
"maximum function durations"),
clEnumValN(GraphRenderer::StatType::SUM, "sum",
"sum of call durations")));
static cl::alias GraphEdgeLabel2("e", cl::aliasopt(GraphEdgeLabel),
cl::desc("Alias for -edge-label"));
static cl::opt<GraphRenderer::StatType> GraphVertexLabel(
"vertex-label",
cl::desc("Output graphs with vertices labeled with this field"),
cl::value_desc("field"), cl::sub(GraphC),
cl::init(GraphRenderer::StatType::NONE),
cl::values(clEnumValN(GraphRenderer::StatType::NONE, "none",
"Do not label Vertices"),
clEnumValN(GraphRenderer::StatType::COUNT, "count",
"function call counts"),
clEnumValN(GraphRenderer::StatType::MIN, "min",
"minimum function durations"),
clEnumValN(GraphRenderer::StatType::MED, "med",
"median function durations"),
clEnumValN(GraphRenderer::StatType::PCT90, "90p",
"90th percentile durations"),
clEnumValN(GraphRenderer::StatType::PCT99, "99p",
"99th percentile durations"),
clEnumValN(GraphRenderer::StatType::MAX, "max",
"maximum function durations"),
clEnumValN(GraphRenderer::StatType::SUM, "sum",
"sum of call durations")));
static cl::alias GraphVertexLabel2("v", cl::aliasopt(GraphVertexLabel),
cl::desc("Alias for -edge-label"));
static cl::opt<GraphRenderer::StatType> GraphEdgeColorType(
"color-edges",
cl::desc("Output graphs with edge colors determined by this field"),
cl::value_desc("field"), cl::sub(GraphC),
cl::init(GraphRenderer::StatType::NONE),
cl::values(clEnumValN(GraphRenderer::StatType::NONE, "none",
"Do not color Edges"),
clEnumValN(GraphRenderer::StatType::COUNT, "count",
"function call counts"),
clEnumValN(GraphRenderer::StatType::MIN, "min",
"minimum function durations"),
clEnumValN(GraphRenderer::StatType::MED, "med",
"median function durations"),
clEnumValN(GraphRenderer::StatType::PCT90, "90p",
"90th percentile durations"),
clEnumValN(GraphRenderer::StatType::PCT99, "99p",
"99th percentile durations"),
clEnumValN(GraphRenderer::StatType::MAX, "max",
"maximum function durations"),
clEnumValN(GraphRenderer::StatType::SUM, "sum",
"sum of call durations")));
static cl::alias GraphEdgeColorType2("c", cl::aliasopt(GraphEdgeColorType),
cl::desc("Alias for -color-edges"));
static cl::opt<GraphRenderer::StatType> GraphVertexColorType(
"color-vertices",
cl::desc("Output graphs with vertex colors determined by this field"),
cl::value_desc("field"), cl::sub(GraphC),
cl::init(GraphRenderer::StatType::NONE),
cl::values(clEnumValN(GraphRenderer::StatType::NONE, "none",
"Do not color vertices"),
clEnumValN(GraphRenderer::StatType::COUNT, "count",
"function call counts"),
clEnumValN(GraphRenderer::StatType::MIN, "min",
"minimum function durations"),
clEnumValN(GraphRenderer::StatType::MED, "med",
"median function durations"),
clEnumValN(GraphRenderer::StatType::PCT90, "90p",
"90th percentile durations"),
clEnumValN(GraphRenderer::StatType::PCT99, "99p",
"99th percentile durations"),
clEnumValN(GraphRenderer::StatType::MAX, "max",
"maximum function durations"),
clEnumValN(GraphRenderer::StatType::SUM, "sum",
"sum of call durations")));
static cl::alias GraphVertexColorType2("b", cl::aliasopt(GraphVertexColorType),
cl::desc("Alias for -edge-label"));
template <class T> T diff(T L, T R) { return std::max(L, R) - std::min(L, R); }
// Updates the statistics for a GraphRenderer::TimeStat
static void updateStat(GraphRenderer::TimeStat &S, int64_t L) {
S.Count++;
if (S.Min > L || S.Min == 0)
S.Min = L;
if (S.Max < L)
S.Max = L;
S.Sum += L;
}
// Labels in a DOT graph must be legal XML strings so it's necessary to escape
// certain characters.
static std::string escapeString(StringRef Label) {
std::string Str;
Str.reserve(Label.size());
for (const auto C : Label) {
switch (C) {
case '&':
Str.append("&amp;");
break;
case '<':
Str.append("&lt;");
break;
case '>':
Str.append("&gt;");
break;
default:
Str.push_back(C);
break;
}
}
return Str;
}
// Evaluates an XRay record and performs accounting on it.
//
// If the record is an ENTER record it pushes the FuncID and TSC onto a
// structure representing the call stack for that function.
// If the record is an EXIT record it checks computes computes the ammount of
// time the function took to complete and then stores that information in an
// edge of the graph. If there is no matching ENTER record the function tries
// to recover by assuming that there were EXIT records which were missed, for
// example caused by tail call elimination and if the option is enabled then
// then tries to recover from this.
//
// This funciton will also error if the records are out of order, as the trace
// is expected to be sorted.
//
// The graph generated has an immaginary root for functions called by no-one at
// FuncId 0.
//
// FIXME: Refactor this and account subcommand to reduce code duplication.
Error GraphRenderer::accountRecord(const XRayRecord &Record) {
using std::make_error_code;
using std::errc;
if (CurrentMaxTSC == 0)
CurrentMaxTSC = Record.TSC;
if (Record.TSC < CurrentMaxTSC)
return make_error<StringError>("Records not in order",
make_error_code(errc::invalid_argument));
auto &ThreadStack = PerThreadFunctionStack[Record.TId];
switch (Record.Type) {
case RecordTypes::ENTER:
case RecordTypes::ENTER_ARG: {
if (Record.FuncId != 0 && G.count(Record.FuncId) == 0)
G[Record.FuncId].SymbolName = FuncIdHelper.SymbolOrNumber(Record.FuncId);
ThreadStack.push_back({Record.FuncId, Record.TSC});
break;
}
case RecordTypes::EXIT:
case RecordTypes::TAIL_EXIT: {
// FIXME: Refactor this and the account subcommand to reduce code
// duplication
if (ThreadStack.size() == 0 || ThreadStack.back().FuncId != Record.FuncId) {
if (!DeduceSiblingCalls)
return make_error<StringError>("No matching ENTRY record",
make_error_code(errc::invalid_argument));
auto Parent = std::find_if(
ThreadStack.rbegin(), ThreadStack.rend(),
[&](const FunctionAttr &A) { return A.FuncId == Record.FuncId; });
if (Parent == ThreadStack.rend())
return make_error<StringError>(
"No matching Entry record in stack",
make_error_code(errc::invalid_argument)); // There is no matching
// Function for this exit.
while (ThreadStack.back().FuncId != Record.FuncId) {
TimestampT D = diff(ThreadStack.back().TSC, Record.TSC);
VertexIdentifier TopFuncId = ThreadStack.back().FuncId;
ThreadStack.pop_back();
assert(ThreadStack.size() != 0);
EdgeIdentifier EI(ThreadStack.back().FuncId, TopFuncId);
auto &EA = G[EI];
EA.Timings.push_back(D);
updateStat(EA.S, D);
updateStat(G[TopFuncId].S, D);
}
}
uint64_t D = diff(ThreadStack.back().TSC, Record.TSC);
ThreadStack.pop_back();
VertexIdentifier VI = ThreadStack.empty() ? 0 : ThreadStack.back().FuncId;
EdgeIdentifier EI(VI, Record.FuncId);
auto &EA = G[EI];
EA.Timings.push_back(D);
updateStat(EA.S, D);
updateStat(G[Record.FuncId].S, D);
break;
}
case RecordTypes::CUSTOM_EVENT:
case RecordTypes::TYPED_EVENT:
// TODO: Support custom and typed events in the graph processing?
break;
}
return Error::success();
}
template <typename U>
void GraphRenderer::getStats(U begin, U end, GraphRenderer::TimeStat &S) {
if (begin == end) return;
std::ptrdiff_t MedianOff = S.Count / 2;
std::nth_element(begin, begin + MedianOff, end);
S.Median = *(begin + MedianOff);
std::ptrdiff_t Pct90Off = (S.Count * 9) / 10;
std::nth_element(begin, begin + Pct90Off, end);
S.Pct90 = *(begin + Pct90Off);
std::ptrdiff_t Pct99Off = (S.Count * 99) / 100;
std::nth_element(begin, begin + Pct99Off, end);
S.Pct99 = *(begin + Pct99Off);
}
void GraphRenderer::updateMaxStats(const GraphRenderer::TimeStat &S,
GraphRenderer::TimeStat &M) {
M.Count = std::max(M.Count, S.Count);
M.Min = std::max(M.Min, S.Min);
M.Median = std::max(M.Median, S.Median);
M.Pct90 = std::max(M.Pct90, S.Pct90);
M.Pct99 = std::max(M.Pct99, S.Pct99);
M.Max = std::max(M.Max, S.Max);
M.Sum = std::max(M.Sum, S.Sum);
}
void GraphRenderer::calculateEdgeStatistics() {
assert(!G.edges().empty());
for (auto &E : G.edges()) {
auto &A = E.second;
assert(!A.Timings.empty());
getStats(A.Timings.begin(), A.Timings.end(), A.S);
updateMaxStats(A.S, G.GraphEdgeMax);
}
}
void GraphRenderer::calculateVertexStatistics() {
std::vector<uint64_t> TempTimings;
for (auto &V : G.vertices()) {
if (V.first != 0) {
for (auto &E : G.inEdges(V.first)) {
auto &A = E.second;
TempTimings.insert(TempTimings.end(), A.Timings.begin(),
A.Timings.end());
}
getStats(TempTimings.begin(), TempTimings.end(), G[V.first].S);
updateMaxStats(G[V.first].S, G.GraphVertexMax);
TempTimings.clear();
}
}
}
// A Helper function for normalizeStatistics which normalises a single
// TimeStat element.
static void normalizeTimeStat(GraphRenderer::TimeStat &S,
double CycleFrequency) {
int64_t OldCount = S.Count;
S = S / CycleFrequency;
S.Count = OldCount;
}
// Normalises the statistics in the graph for a given TSC frequency.
void GraphRenderer::normalizeStatistics(double CycleFrequency) {
for (auto &E : G.edges()) {
auto &S = E.second.S;
normalizeTimeStat(S, CycleFrequency);
}
for (auto &V : G.vertices()) {
auto &S = V.second.S;
normalizeTimeStat(S, CycleFrequency);
}
normalizeTimeStat(G.GraphEdgeMax, CycleFrequency);
normalizeTimeStat(G.GraphVertexMax, CycleFrequency);
}
// Returns a string containing the value of statistic field T
std::string
GraphRenderer::TimeStat::getString(GraphRenderer::StatType T) const {
std::string St;
raw_string_ostream S{St};
double TimeStat::*DoubleStatPtrs[] = {&TimeStat::Min, &TimeStat::Median,
&TimeStat::Pct90, &TimeStat::Pct99,
&TimeStat::Max, &TimeStat::Sum};
switch (T) {
case GraphRenderer::StatType::NONE:
break;
case GraphRenderer::StatType::COUNT:
S << Count;
break;
default:
S << (*this).*
DoubleStatPtrs[static_cast<int>(T) -
static_cast<int>(GraphRenderer::StatType::MIN)];
break;
}
return S.str();
}
// Returns the quotient between the property T of this and another TimeStat as
// a double
double GraphRenderer::TimeStat::getDouble(StatType T) const {
double retval = 0;
double TimeStat::*DoubleStatPtrs[] = {&TimeStat::Min, &TimeStat::Median,
&TimeStat::Pct90, &TimeStat::Pct99,
&TimeStat::Max, &TimeStat::Sum};
switch (T) {
case GraphRenderer::StatType::NONE:
retval = 0.0;
break;
case GraphRenderer::StatType::COUNT:
retval = static_cast<double>(Count);
break;
default:
retval =
(*this).*DoubleStatPtrs[static_cast<int>(T) -
static_cast<int>(GraphRenderer::StatType::MIN)];
break;
}
return retval;
}
// Outputs a DOT format version of the Graph embedded in the GraphRenderer
// object on OS. It does this in the expected way by itterating
// through all edges then vertices and then outputting them and their
// annotations.
//
// FIXME: output more information, better presented.
void GraphRenderer::exportGraphAsDOT(raw_ostream &OS, StatType ET, StatType EC,
StatType VT, StatType VC) {
OS << "digraph xray {\n";
if (VT != StatType::NONE)
OS << "node [shape=record];\n";
for (const auto &E : G.edges()) {
const auto &S = E.second.S;
OS << "F" << E.first.first << " -> "
<< "F" << E.first.second << " [label=\"" << S.getString(ET) << "\"";
if (EC != StatType::NONE)
OS << " color=\""
<< CHelper.getColorString(
std::sqrt(S.getDouble(EC) / G.GraphEdgeMax.getDouble(EC)))
<< "\"";
OS << "];\n";
}
for (const auto &V : G.vertices()) {
const auto &VA = V.second;
if (V.first == 0)
continue;
OS << "F" << V.first << " [label=\"" << (VT != StatType::NONE ? "{" : "")
<< escapeString(VA.SymbolName.size() > 40
? VA.SymbolName.substr(0, 40) + "..."
: VA.SymbolName);
if (VT != StatType::NONE)
OS << "|" << VA.S.getString(VT) << "}\"";
else
OS << "\"";
if (VC != StatType::NONE)
OS << " color=\""
<< CHelper.getColorString(
std::sqrt(VA.S.getDouble(VC) / G.GraphVertexMax.getDouble(VC)))
<< "\"";
OS << "];\n";
}
OS << "}\n";
}
Expected<GraphRenderer> GraphRenderer::Factory::getGraphRenderer() {
InstrumentationMap Map;
if (!GraphInstrMap.empty()) {
auto InstrumentationMapOrError = loadInstrumentationMap(GraphInstrMap);
if (!InstrumentationMapOrError)
return joinErrors(
make_error<StringError>(
Twine("Cannot open instrumentation map '") + GraphInstrMap + "'",
std::make_error_code(std::errc::invalid_argument)),
InstrumentationMapOrError.takeError());
Map = std::move(*InstrumentationMapOrError);
}
const auto &FunctionAddresses = Map.getFunctionAddresses();
symbolize::LLVMSymbolizer Symbolizer;
const auto &Header = Trace.getFileHeader();
llvm::xray::FuncIdConversionHelper FuncIdHelper(InstrMap, Symbolizer,
FunctionAddresses);
xray::GraphRenderer GR(FuncIdHelper, DeduceSiblingCalls);
for (const auto &Record : Trace) {
auto E = GR.accountRecord(Record);
if (!E)
continue;
for (const auto &ThreadStack : GR.getPerThreadFunctionStack()) {
errs() << "Thread ID: " << ThreadStack.first << "\n";
auto Level = ThreadStack.second.size();
for (const auto &Entry : llvm::reverse(ThreadStack.second))
errs() << "#" << Level-- << "\t"
<< FuncIdHelper.SymbolOrNumber(Entry.FuncId) << '\n';
}
if (!GraphKeepGoing)
return joinErrors(make_error<StringError>(
"Error encountered generating the call graph.",
std::make_error_code(std::errc::invalid_argument)),
std::move(E));
handleAllErrors(std::move(E),
[&](const ErrorInfoBase &E) { E.log(errs()); });
}
GR.G.GraphEdgeMax = {};
GR.G.GraphVertexMax = {};
GR.calculateEdgeStatistics();
GR.calculateVertexStatistics();
if (Header.CycleFrequency)
GR.normalizeStatistics(Header.CycleFrequency);
return GR;
}
// Here we register and implement the llvm-xray graph subcommand.
// The bulk of this code reads in the options, opens the required files, uses
// those files to create a context for analysing the xray trace, then there is a
// short loop which actually analyses the trace, generates the graph and then
// outputs it as a DOT.
//
// FIXME: include additional filtering and annalysis passes to provide more
// specific useful information.
static CommandRegistration Unused(&GraphC, []() -> Error {
GraphRenderer::Factory F;
F.KeepGoing = GraphKeepGoing;
F.DeduceSiblingCalls = GraphDeduceSiblingCalls;
F.InstrMap = GraphInstrMap;
auto TraceOrErr = loadTraceFile(GraphInput, true);
if (!TraceOrErr)
return make_error<StringError>(
Twine("Failed loading input file '") + GraphInput + "'",
make_error_code(llvm::errc::invalid_argument));
F.Trace = std::move(*TraceOrErr);
auto GROrError = F.getGraphRenderer();
if (!GROrError)
return GROrError.takeError();
auto &GR = *GROrError;
std::error_code EC;
raw_fd_ostream OS(GraphOutput, EC, sys::fs::OpenFlags::OF_Text);
if (EC)
return make_error<StringError>(
Twine("Cannot open file '") + GraphOutput + "' for writing.", EC);
GR.exportGraphAsDOT(OS, GraphEdgeLabel, GraphEdgeColorType, GraphVertexLabel,
GraphVertexColorType);
return Error::success();
});
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