c4fb7180cb
Lots of code around LLDB was directly accessing the target's section load list. This NFC patch makes the section load list private so the Target class can access it, but everyone else now uses accessor functions. This allows us to control the resolving of addresses and will allow for functionality in LLDB which can lazily resolve addresses in JIT plug-ins with a future patch.
402 lines
14 KiB
C++
402 lines
14 KiB
C++
//===-- TraceIntelPTBundleSaver.cpp ---------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "TraceIntelPTBundleSaver.h"
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#include "PerfContextSwitchDecoder.h"
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#include "TraceIntelPT.h"
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#include "TraceIntelPTConstants.h"
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#include "TraceIntelPTJSONStructs.h"
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#include "lldb/Core/Module.h"
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#include "lldb/Core/ModuleList.h"
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#include "lldb/Target/Process.h"
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#include "lldb/Target/SectionLoadList.h"
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#include "lldb/Target/Target.h"
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#include "lldb/Target/ThreadList.h"
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#include "lldb/lldb-types.h"
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#include "llvm/Support/Error.h"
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#include "llvm/Support/JSON.h"
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#include <fstream>
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#include <iostream>
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#include <optional>
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#include <sstream>
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#include <string>
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using namespace lldb;
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using namespace lldb_private;
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using namespace lldb_private::trace_intel_pt;
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using namespace llvm;
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/// Strip the \p directory component from the given \p path. It assumes that \p
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/// directory is a prefix of \p path.
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static std::string GetRelativePath(const FileSpec &directory,
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const FileSpec &path) {
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return path.GetPath().substr(directory.GetPath().size() + 1);
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}
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/// Write a stream of bytes from \p data to the given output file.
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/// It creates or overwrites the output file, but not append.
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static llvm::Error WriteBytesToDisk(FileSpec &output_file,
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ArrayRef<uint8_t> data) {
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std::basic_fstream<char> out_fs = std::fstream(
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output_file.GetPath().c_str(), std::ios::out | std::ios::binary);
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if (!data.empty())
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out_fs.write(reinterpret_cast<const char *>(&data[0]), data.size());
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out_fs.close();
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if (!out_fs)
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return createStringError(inconvertibleErrorCode(),
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formatv("couldn't write to the file {0}",
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output_file.GetPath().c_str()));
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return Error::success();
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}
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/// Save the trace bundle description JSON object inside the given directory
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/// as a file named \a trace.json.
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///
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/// \param[in] trace_bundle_description
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/// The trace bundle description as JSON Object.
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///
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/// \param[in] directory
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/// The directory where the JSON file will be saved.
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///
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/// \return
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/// A \a FileSpec pointing to the bundle description file, or an \a
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/// llvm::Error otherwise.
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static Expected<FileSpec>
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SaveTraceBundleDescription(const llvm::json::Value &trace_bundle_description,
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const FileSpec &directory) {
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FileSpec trace_path = directory;
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trace_path.AppendPathComponent("trace.json");
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std::ofstream os(trace_path.GetPath());
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os << formatv("{0:2}", trace_bundle_description).str();
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os.close();
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if (!os)
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return createStringError(inconvertibleErrorCode(),
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formatv("couldn't write to the file {0}",
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trace_path.GetPath().c_str()));
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return trace_path;
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}
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/// Build the threads sub-section of the trace bundle description file.
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/// Any associated binary files are created inside the given directory.
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///
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/// \param[in] process
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/// The process being traced.
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///
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/// \param[in] directory
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/// The directory where files will be saved when building the threads
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/// section.
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///
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/// \return
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/// The threads section or \a llvm::Error in case of failures.
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static llvm::Expected<std::vector<JSONThread>>
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BuildThreadsSection(Process &process, FileSpec directory) {
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std::vector<JSONThread> json_threads;
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TraceSP trace_sp = process.GetTarget().GetTrace();
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FileSpec threads_dir = directory;
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threads_dir.AppendPathComponent("threads");
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sys::fs::create_directories(threads_dir.GetPath().c_str());
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for (ThreadSP thread_sp : process.Threads()) {
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lldb::tid_t tid = thread_sp->GetID();
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if (!trace_sp->IsTraced(tid))
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continue;
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JSONThread json_thread;
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json_thread.tid = tid;
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if (trace_sp->GetTracedCpus().empty()) {
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FileSpec output_file = threads_dir;
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output_file.AppendPathComponent(std::to_string(tid) + ".intelpt_trace");
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json_thread.ipt_trace = GetRelativePath(directory, output_file);
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llvm::Error err = process.GetTarget().GetTrace()->OnThreadBinaryDataRead(
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tid, IntelPTDataKinds::kIptTrace,
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[&](llvm::ArrayRef<uint8_t> data) -> llvm::Error {
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return WriteBytesToDisk(output_file, data);
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});
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if (err)
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return std::move(err);
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}
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json_threads.push_back(std::move(json_thread));
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}
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return json_threads;
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}
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/// \return
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/// an \a llvm::Error in case of failures, \a std::nullopt if the trace is not
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/// written to disk because the trace is empty and the \p compact flag is
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/// present, or the FileSpec of the trace file on disk.
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static Expected<std::optional<FileSpec>>
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WriteContextSwitchTrace(TraceIntelPT &trace_ipt, lldb::cpu_id_t cpu_id,
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const FileSpec &cpus_dir, bool compact) {
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FileSpec output_context_switch_trace = cpus_dir;
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output_context_switch_trace.AppendPathComponent(std::to_string(cpu_id) +
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".perf_context_switch_trace");
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bool should_skip = false;
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Error err = trace_ipt.OnCpuBinaryDataRead(
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cpu_id, IntelPTDataKinds::kPerfContextSwitchTrace,
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[&](llvm::ArrayRef<uint8_t> data) -> llvm::Error {
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if (!compact)
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return WriteBytesToDisk(output_context_switch_trace, data);
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std::set<lldb::pid_t> pids;
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for (Process *process : trace_ipt.GetAllProcesses())
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pids.insert(process->GetID());
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Expected<std::vector<uint8_t>> compact_context_switch_trace =
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FilterProcessesFromContextSwitchTrace(data, pids);
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if (!compact_context_switch_trace)
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return compact_context_switch_trace.takeError();
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if (compact_context_switch_trace->empty()) {
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should_skip = true;
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return Error::success();
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}
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return WriteBytesToDisk(output_context_switch_trace,
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*compact_context_switch_trace);
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});
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if (err)
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return std::move(err);
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if (should_skip)
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return std::nullopt;
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return output_context_switch_trace;
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}
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static Expected<FileSpec> WriteIntelPTTrace(TraceIntelPT &trace_ipt,
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lldb::cpu_id_t cpu_id,
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const FileSpec &cpus_dir) {
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FileSpec output_trace = cpus_dir;
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output_trace.AppendPathComponent(std::to_string(cpu_id) + ".intelpt_trace");
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Error err = trace_ipt.OnCpuBinaryDataRead(
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cpu_id, IntelPTDataKinds::kIptTrace,
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[&](llvm::ArrayRef<uint8_t> data) -> llvm::Error {
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return WriteBytesToDisk(output_trace, data);
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});
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if (err)
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return std::move(err);
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return output_trace;
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}
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static llvm::Expected<std::optional<std::vector<JSONCpu>>>
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BuildCpusSection(TraceIntelPT &trace_ipt, FileSpec directory, bool compact) {
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if (trace_ipt.GetTracedCpus().empty())
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return std::nullopt;
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std::vector<JSONCpu> json_cpus;
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FileSpec cpus_dir = directory;
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cpus_dir.AppendPathComponent("cpus");
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sys::fs::create_directories(cpus_dir.GetPath().c_str());
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for (lldb::cpu_id_t cpu_id : trace_ipt.GetTracedCpus()) {
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JSONCpu json_cpu;
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json_cpu.id = cpu_id;
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Expected<std::optional<FileSpec>> context_switch_trace_path =
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WriteContextSwitchTrace(trace_ipt, cpu_id, cpus_dir, compact);
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if (!context_switch_trace_path)
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return context_switch_trace_path.takeError();
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if (!*context_switch_trace_path)
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continue;
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json_cpu.context_switch_trace =
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GetRelativePath(directory, **context_switch_trace_path);
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if (Expected<FileSpec> ipt_trace_path =
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WriteIntelPTTrace(trace_ipt, cpu_id, cpus_dir))
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json_cpu.ipt_trace = GetRelativePath(directory, *ipt_trace_path);
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else
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return ipt_trace_path.takeError();
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json_cpus.push_back(std::move(json_cpu));
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}
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return json_cpus;
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}
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/// Build modules sub-section of the trace bundle. The original modules
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/// will be copied over to the \a <directory/modules> folder. Invalid modules
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/// are skipped.
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/// Copying the modules has the benefit of making these
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/// directories self-contained, as the raw traces and modules are part of the
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/// output directory and can be sent to another machine, where lldb can load
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/// them and replicate exactly the same trace session.
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///
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/// \param[in] process
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/// The process being traced.
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///
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/// \param[in] directory
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/// The directory where the modules files will be saved when building
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/// the modules section.
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/// Example: If a module \a libbar.so exists in the path
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/// \a /usr/lib/foo/libbar.so, then it will be copied to
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/// \a <directory>/modules/usr/lib/foo/libbar.so.
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///
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/// \return
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/// The modules section or \a llvm::Error in case of failures.
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static llvm::Expected<std::vector<JSONModule>>
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BuildModulesSection(Process &process, FileSpec directory) {
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std::vector<JSONModule> json_modules;
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ModuleList module_list = process.GetTarget().GetImages();
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for (size_t i = 0; i < module_list.GetSize(); ++i) {
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ModuleSP module_sp(module_list.GetModuleAtIndex(i));
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if (!module_sp)
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continue;
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std::string system_path = module_sp->GetPlatformFileSpec().GetPath();
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// TODO: support memory-only libraries like [vdso]
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if (!module_sp->GetFileSpec().IsAbsolute())
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continue;
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std::string file = module_sp->GetFileSpec().GetPath();
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ObjectFile *objfile = module_sp->GetObjectFile();
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if (objfile == nullptr)
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continue;
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lldb::addr_t load_addr = LLDB_INVALID_ADDRESS;
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Address base_addr(objfile->GetBaseAddress());
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if (base_addr.IsValid() && process.GetTarget().HasLoadedSections())
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load_addr = base_addr.GetLoadAddress(&process.GetTarget());
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if (load_addr == LLDB_INVALID_ADDRESS)
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continue;
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FileSpec path_to_copy_module = directory;
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path_to_copy_module.AppendPathComponent("modules");
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path_to_copy_module.AppendPathComponent(system_path);
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sys::fs::create_directories(path_to_copy_module.GetDirectory().AsCString());
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if (std::error_code ec =
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llvm::sys::fs::copy_file(file, path_to_copy_module.GetPath()))
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return createStringError(
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inconvertibleErrorCode(),
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formatv("couldn't write to the file. {0}", ec.message()));
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json_modules.push_back(
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JSONModule{system_path, GetRelativePath(directory, path_to_copy_module),
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JSONUINT64{load_addr}, module_sp->GetUUID().GetAsString()});
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}
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return json_modules;
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}
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/// Build the processes section of the trace bundle description object. Besides
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/// returning the processes information, this method saves to disk all modules
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/// and raw traces corresponding to the traced threads of the given process.
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///
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/// \param[in] process
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/// The process being traced.
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///
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/// \param[in] directory
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/// The directory where files will be saved when building the processes
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/// section.
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///
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/// \return
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/// The processes section or \a llvm::Error in case of failures.
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static llvm::Expected<JSONProcess>
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BuildProcessSection(Process &process, const FileSpec &directory) {
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Expected<std::vector<JSONThread>> json_threads =
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BuildThreadsSection(process, directory);
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if (!json_threads)
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return json_threads.takeError();
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Expected<std::vector<JSONModule>> json_modules =
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BuildModulesSection(process, directory);
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if (!json_modules)
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return json_modules.takeError();
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return JSONProcess{
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process.GetID(),
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process.GetTarget().GetArchitecture().GetTriple().getTriple(),
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json_threads.get(), json_modules.get()};
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}
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/// See BuildProcessSection()
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static llvm::Expected<std::vector<JSONProcess>>
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BuildProcessesSection(TraceIntelPT &trace_ipt, const FileSpec &directory) {
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std::vector<JSONProcess> processes;
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for (Process *process : trace_ipt.GetAllProcesses()) {
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if (llvm::Expected<JSONProcess> json_process =
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BuildProcessSection(*process, directory))
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processes.push_back(std::move(*json_process));
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else
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return json_process.takeError();
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}
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return processes;
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}
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static llvm::Expected<JSONKernel>
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BuildKernelSection(TraceIntelPT &trace_ipt, const FileSpec &directory) {
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JSONKernel json_kernel;
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std::vector<Process *> processes = trace_ipt.GetAllProcesses();
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Process *kernel_process = processes[0];
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assert(processes.size() == 1 && "User processeses exist in kernel mode");
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assert(kernel_process->GetID() == kDefaultKernelProcessID &&
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"Kernel process not exist");
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Expected<std::vector<JSONModule>> json_modules =
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BuildModulesSection(*kernel_process, directory);
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if (!json_modules)
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return json_modules.takeError();
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JSONModule kernel_image = json_modules.get()[0];
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return JSONKernel{kernel_image.load_address, kernel_image.system_path};
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}
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Expected<FileSpec> TraceIntelPTBundleSaver::SaveToDisk(TraceIntelPT &trace_ipt,
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FileSpec directory,
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bool compact) {
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if (std::error_code ec =
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sys::fs::create_directories(directory.GetPath().c_str()))
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return llvm::errorCodeToError(ec);
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Expected<pt_cpu> cpu_info = trace_ipt.GetCPUInfo();
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if (!cpu_info)
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return cpu_info.takeError();
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FileSystem::Instance().Resolve(directory);
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Expected<std::optional<std::vector<JSONCpu>>> json_cpus =
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BuildCpusSection(trace_ipt, directory, compact);
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if (!json_cpus)
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return json_cpus.takeError();
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std::optional<std::vector<JSONProcess>> json_processes;
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std::optional<JSONKernel> json_kernel;
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if (trace_ipt.GetTraceMode() == TraceIntelPT::TraceMode::KernelMode) {
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Expected<std::optional<JSONKernel>> exp_json_kernel =
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BuildKernelSection(trace_ipt, directory);
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if (!exp_json_kernel)
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return exp_json_kernel.takeError();
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else
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json_kernel = *exp_json_kernel;
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} else {
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Expected<std::optional<std::vector<JSONProcess>>> exp_json_processes =
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BuildProcessesSection(trace_ipt, directory);
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if (!exp_json_processes)
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return exp_json_processes.takeError();
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else
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json_processes = *exp_json_processes;
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}
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JSONTraceBundleDescription json_intel_pt_bundle_desc{
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"intel-pt",
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*cpu_info,
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json_processes,
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*json_cpus,
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trace_ipt.GetPerfZeroTscConversion(),
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json_kernel};
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return SaveTraceBundleDescription(toJSON(json_intel_pt_bundle_desc),
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directory);
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}
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