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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/globals.h"
#if defined(DART_HOST_OS_LINUX)
#include "vm/os.h"
#include <dlfcn.h> // NOLINT
#include <elf.h> // NOLINT
#include <errno.h> // NOLINT
#include <fcntl.h> // NOLINT
#include <limits.h> // NOLINT
#include <malloc.h> // NOLINT
#include <sys/mman.h> // NOLINT
#include <sys/resource.h> // NOLINT
#include <sys/stat.h> // NOLINT
#include <sys/syscall.h> // NOLINT
#include <sys/time.h> // NOLINT
#include <sys/types.h> // NOLINT
#include <time.h> // NOLINT
#include <unistd.h> // NOLINT
#include "platform/memory_sanitizer.h"
#include "platform/utils.h"
#include "vm/code_comments.h"
#include "vm/code_observers.h"
#include "vm/dart.h"
#include "vm/flags.h"
#include "vm/image_snapshot.h"
#include "vm/isolate.h"
#include "vm/lockers.h"
#include "vm/os_thread.h"
#include "vm/timeline.h"
#include "vm/zone.h"
namespace dart {
// Used to choose between Elf32/Elf64 types based on host archotecture bitsize.
#if defined(ARCH_IS_64_BIT)
#define ElfW(Type) Elf64_##Type
#else
#define ElfW(Type) Elf32_##Type
#endif
// Missing from older versions of <elf.h>.
#if !defined(EM_RISCV)
#define EM_RISCV 243
#endif
#ifndef PRODUCT
DEFINE_FLAG(bool,
generate_perf_events_symbols,
false,
"Generate events symbols for profiling with perf (disables dual "
"code mapping)");
DEFINE_FLAG(bool,
generate_perf_jitdump,
false,
"Generate jitdump file to use with perf-inject (disables dual code "
"mapping)");
DECLARE_FLAG(bool, write_protect_code);
DECLARE_FLAG(bool, write_protect_vm_isolate);
#if !defined(DART_PRECOMPILED_RUNTIME)
DECLARE_FLAG(bool, code_comments);
#endif
// Linux CodeObservers.
// Simple perf support: generate /tmp/perf-<pid>.map file that maps
// memory ranges to symbol names for JIT generated code. This allows
// perf-report to resolve addresses falling into JIT generated code.
// However perf-annotate does not work in this mode because JIT code
// is transient and does not exist anymore at the moment when you
// invoke perf-report.
class PerfCodeObserver : public CodeObserver {
public:
PerfCodeObserver() : out_file_(nullptr) {
Dart_FileOpenCallback file_open = Dart::file_open_callback();
if (file_open == nullptr) {
return;
}
intptr_t pid = getpid();
char* filename = OS::SCreate(nullptr, "/tmp/perf-%" Pd ".map", pid);
out_file_ = (*file_open)(filename, true);
free(filename);
}
~PerfCodeObserver() {
Dart_FileCloseCallback file_close = Dart::file_close_callback();
if ((file_close == nullptr) || (out_file_ == nullptr)) {
return;
}
(*file_close)(out_file_);
}
virtual bool IsActive() const {
return FLAG_generate_perf_events_symbols && (out_file_ != nullptr);
}
virtual void Notify(const char* name,
uword base,
uword prologue_offset,
uword size,
bool optimized,
const CodeComments* comments) {
Dart_FileWriteCallback file_write = Dart::file_write_callback();
if ((file_write == nullptr) || (out_file_ == nullptr)) {
return;
}
const char* marker = optimized ? "*" : "";
char* buffer =
OS::SCreate(Thread::Current()->zone(), "%" Px " %" Px " %s%s\n", base,
size, marker, name);
{
MutexLocker ml(CodeObservers::mutex());
(*file_write)(buffer, strlen(buffer), out_file_);
}
}
private:
void* out_file_;
DISALLOW_COPY_AND_ASSIGN(PerfCodeObserver);
};
// Code observer that generates a JITDUMP[1] file that can be interpreted by
// perf-inject to generate ELF images for JIT generated code objects, which
// allows both perf-report and perf-annotate to recognize them.
//
// Usage:
//
// $ perf record -k mono dart --generate-perf-jitdump benchmark.dart
// $ perf inject -j -i perf.data -o perf.data.jitted
// $ perf report -i perf.data.jitted
//
// [1] see linux/tools/perf/Documentation/jitdump-specification.txt for
// JITDUMP binary format.
class JitDumpCodeObserver : public CodeObserver {
public:
JitDumpCodeObserver() : pid_(getpid()) {
char* const filename = OS::SCreate(nullptr, "/tmp/jit-%" Pd ".dump", pid_);
const int fd = open(filename, O_CREAT | O_TRUNC | O_RDWR, 0666);
free(filename);
if (fd == -1) {
return;
}
// Map JITDUMP file, this mapping will be recorded by perf. This allows
// perf-inject to find this file later.
const long page_size = sysconf(_SC_PAGESIZE); // NOLINT(runtime/int)
if (page_size == -1) {
close(fd);
return;
}
mapped_ =
mmap(nullptr, page_size, PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0);
if (mapped_ == nullptr) {
close(fd);
return;
}
mapped_size_ = page_size;
out_file_ = fdopen(fd, "w+");
if (out_file_ == nullptr) {
close(fd);
return;
}
// Buffer the output to avoid high IO overheads - we are going to be
// writing all JIT generated code out.
setvbuf(out_file_, nullptr, _IOFBF, 2 * MB);
// Disable code write protection and vm isolate write protection, because
// calling mprotect on the pages filled with JIT generated code objects
// confuses perf.
FLAG_write_protect_code = false;
FLAG_write_protect_vm_isolate = false;
#if !defined(DART_PRECOMPILED_RUNTIME)
// Enable code comments.
FLAG_code_comments = true;
#endif
// Write JITDUMP header.
WriteHeader();
}
~JitDumpCodeObserver() {
if (mapped_ != nullptr) {
munmap(mapped_, mapped_size_);
mapped_ = nullptr;
}
if (out_file_ != nullptr) {
fclose(out_file_);
out_file_ = nullptr;
}
}
virtual bool IsActive() const {
return FLAG_generate_perf_jitdump && (out_file_ != nullptr);
}
virtual void Notify(const char* name,
uword base,
uword prologue_offset,
uword size,
bool optimized,
const CodeComments* comments) {
MutexLocker ml(CodeObservers::mutex());
const char* marker = optimized ? "*" : "";
char* buffer = OS::SCreate(Thread::Current()->zone(), "%s%s", marker, name);
const size_t name_length = strlen(buffer);
WriteDebugInfo(base, comments);
CodeLoadEvent ev;
ev.event = BaseEvent::kLoad;
ev.size = sizeof(ev) + (name_length + 1) + size;
ev.time_stamp = OS::GetCurrentMonotonicTicks();
ev.process_id = getpid();
ev.thread_id = syscall(SYS_gettid);
ev.vma = base;
ev.code_address = base;
ev.code_size = size;
ev.code_id = code_id_++;
WriteFully(&ev, sizeof(ev));
WriteFully(buffer, name_length + 1);
WriteFully(reinterpret_cast<void*>(base), size);
}
private:
struct Header {
const uint32_t magic = 0x4A695444;
const uint32_t version = 1;
const uint32_t size = sizeof(Header);
uint32_t elf_mach_target;
const uint32_t reserved = 0xDEADBEEF;
uint32_t process_id;
uint64_t time_stamp;
const uint64_t flags = 0;
};
struct BaseEvent {
enum Event {
kLoad = 0,
kMove = 1,
kDebugInfo = 2,
kClose = 3,
kUnwindingInfo = 4
};
uint32_t event;
uint32_t size;
uint64_t time_stamp;
};
struct CodeLoadEvent : BaseEvent {
uint32_t process_id;
uint32_t thread_id;
uint64_t vma;
uint64_t code_address;
uint64_t code_size;
uint64_t code_id;
};
struct DebugInfoEvent : BaseEvent {
uint64_t address;
uint64_t entry_count;
// DebugInfoEntry entries[entry_count_];
};
struct DebugInfoEntry {
uint64_t address;
int32_t line_number;
int32_t column;
// Followed by nul-terminated name.
};
static uint32_t GetElfMachineArchitecture() {
#if TARGET_ARCH_IA32
return EM_386;
#elif TARGET_ARCH_X64
return EM_X86_64;
#elif TARGET_ARCH_ARM
return EM_ARM;
#elif TARGET_ARCH_ARM64
return EM_AARCH64;
#elif TARGET_ARCH_RISCV32 || TARGET_ARCH_RISCV64
return EM_RISCV;
#else
UNREACHABLE();
return 0;
#endif
}
void WriteDebugInfo(uword base, const CodeComments* comments) {
if (comments == nullptr || comments->Length() == 0) {
return;
}
// Open the comments file for the given code object.
// Note: for some reason we can't emit all comments into a single file
// the mapping between PCs and lines goes out of sync (might be
// perf-annotate bug).
char* comments_file_name =
OS::SCreate(nullptr, "/tmp/jit-%" Pd "-%" Pd ".cmts", pid_, code_id_);
const intptr_t filename_length = strlen(comments_file_name);
FILE* comments_file = fopen(comments_file_name, "w");
setvbuf(comments_file, nullptr, _IOFBF, 2 * MB);
// Count the number of DebugInfoEntry we are going to emit: one
// per PC.
intptr_t entry_count = 0;
for (uint64_t i = 0, len = comments->Length(); i < len;) {
const intptr_t pc_offset = comments->PCOffsetAt(i);
while (i < len && comments->PCOffsetAt(i) == pc_offset) {
i++;
}
entry_count++;
}
DebugInfoEvent info;
info.event = BaseEvent::kDebugInfo;
info.time_stamp = OS::GetCurrentMonotonicTicks();
info.address = base;
info.entry_count = entry_count;
info.size = sizeof(info) +
entry_count * (sizeof(DebugInfoEntry) + filename_length + 1);
const int32_t padding = Utils::RoundUp(info.size, 8) - info.size;
info.size += padding;
// Write out DebugInfoEvent record followed by entry_count DebugInfoEntry
// records.
WriteFully(&info, sizeof(info));
intptr_t line_number = 0; // Line number within comments_file.
for (intptr_t i = 0, len = comments->Length(); i < len;) {
const intptr_t pc_offset = comments->PCOffsetAt(i);
while (i < len && comments->PCOffsetAt(i) == pc_offset) {
line_number += WriteLn(comments_file, comments->CommentAt(i));
i++;
}
DebugInfoEntry entry;
entry.address = base + pc_offset + sizeof(ElfW(Ehdr));
entry.line_number = line_number;
entry.column = 0;
WriteFully(&entry, sizeof(entry));
WriteFully(comments_file_name, filename_length + 1);
}
// Write out the padding.
const char padding_bytes[8] = {0};
WriteFully(padding_bytes, padding);
fclose(comments_file);
free(comments_file_name);
}
void WriteHeader() {
Header header;
header.elf_mach_target = GetElfMachineArchitecture();
header.process_id = getpid();
header.time_stamp = OS::GetCurrentTimeMicros();
WriteFully(&header, sizeof(header));
}
// Returns number of new-lines written.
intptr_t WriteLn(FILE* f, const char* comment) {
fputs(comment, f);
fputc('\n', f);
intptr_t line_count = 1;
while ((comment = strstr(comment, "\n")) != nullptr) {
line_count++;
}
return line_count;
}
void WriteFully(const void* buffer, size_t size) {
const char* ptr = static_cast<const char*>(buffer);
while (size > 0) {
const size_t written = fwrite(ptr, 1, size, out_file_);
if (written == 0) {
UNREACHABLE();
break;
}
size -= written;
ptr += written;
}
}
const intptr_t pid_;
FILE* out_file_ = nullptr;
void* mapped_ = nullptr;
long mapped_size_ = 0; // NOLINT(runtime/int)
intptr_t code_id_ = 0;
DISALLOW_COPY_AND_ASSIGN(JitDumpCodeObserver);
};
#endif // !PRODUCT
intptr_t OS::ProcessId() {
return static_cast<intptr_t>(getpid());
}
static bool LocalTime(int64_t seconds_since_epoch, tm* tm_result) {
time_t seconds = static_cast<time_t>(seconds_since_epoch);
if (seconds != seconds_since_epoch) return false;
struct tm* error_code = localtime_r(&seconds, tm_result);
return error_code != nullptr;
}
const char* OS::GetTimeZoneName(int64_t seconds_since_epoch) {
tm decomposed;
bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
// If unsuccessful, return an empty string like V8 does.
return (succeeded && (decomposed.tm_zone != nullptr)) ? decomposed.tm_zone
: "";
}
int OS::GetTimeZoneOffsetInSeconds(int64_t seconds_since_epoch) {
tm decomposed;
bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
// Even if the offset was 24 hours it would still easily fit into 32 bits.
// If unsuccessful, return zero like V8 does.
return succeeded ? static_cast<int>(decomposed.tm_gmtoff) : 0;
}
int64_t OS::GetCurrentTimeMillis() {
return GetCurrentTimeMicros() / 1000;
}
int64_t OS::GetCurrentTimeMicros() {
// gettimeofday has microsecond resolution.
struct timeval tv;
if (gettimeofday(&tv, nullptr) < 0) {
UNREACHABLE();
return 0;
}
return (static_cast<int64_t>(tv.tv_sec) * 1000000) + tv.tv_usec;
}
int64_t OS::GetCurrentMonotonicTicks() {
struct timespec ts;
if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) {
UNREACHABLE();
return 0;
}
// Convert to nanoseconds.
int64_t result = ts.tv_sec;
result *= kNanosecondsPerSecond;
result += ts.tv_nsec;
return result;
}
int64_t OS::GetCurrentMonotonicFrequency() {
return kNanosecondsPerSecond;
}
int64_t OS::GetCurrentMonotonicMicros() {
int64_t ticks = GetCurrentMonotonicTicks();
ASSERT(GetCurrentMonotonicFrequency() == kNanosecondsPerSecond);
return ticks / kNanosecondsPerMicrosecond;
}
int64_t OS::GetCurrentThreadCPUMicros() {
struct timespec ts;
if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts) != 0) {
UNREACHABLE();
return -1;
}
int64_t result = ts.tv_sec;
result *= kMicrosecondsPerSecond;
result += (ts.tv_nsec / kNanosecondsPerMicrosecond);
return result;
}
int64_t OS::GetCurrentMonotonicMicrosForTimeline() {
#if defined(SUPPORT_TIMELINE)
if (Timeline::recorder_discards_clock_values()) return -1;
return GetCurrentMonotonicMicros();
#else
return -1;
#endif
}
// TODO(5411554): May need to hoist these architecture dependent code
// into a architecture specific file e.g: os_ia32_linux.cc
intptr_t OS::ActivationFrameAlignment() {
#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64) || \
defined(TARGET_ARCH_ARM64) || defined(TARGET_ARCH_RISCV32) || \
defined(TARGET_ARCH_RISCV64)
const int kMinimumAlignment = 16;
#elif defined(TARGET_ARCH_ARM)
const int kMinimumAlignment = 8;
#else
#error Unsupported architecture.
#endif
intptr_t alignment = kMinimumAlignment;
// TODO(5411554): Allow overriding default stack alignment for
// testing purposes.
// Flags::DebugIsInt("stackalign", &alignment);
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(alignment >= kMinimumAlignment);
return alignment;
}
int OS::NumberOfAvailableProcessors() {
return sysconf(_SC_NPROCESSORS_ONLN);
}
void OS::Sleep(int64_t millis) {
int64_t micros = millis * kMicrosecondsPerMillisecond;
SleepMicros(micros);
}
void OS::SleepMicros(int64_t micros) {
struct timespec req; // requested.
struct timespec rem; // remainder.
int64_t seconds = micros / kMicrosecondsPerSecond;
micros = micros - seconds * kMicrosecondsPerSecond;
int64_t nanos = micros * kNanosecondsPerMicrosecond;
req.tv_sec = seconds;
req.tv_nsec = nanos;
while (true) {
int r = nanosleep(&req, &rem);
if (r == 0) {
break;
}
// We should only ever see an interrupt error.
ASSERT(errno == EINTR);
// Copy remainder into requested and repeat.
req = rem;
}
}
// TODO(regis): Function called only from the simulator.
void OS::DebugBreak() {
__builtin_trap();
}
DART_NOINLINE uintptr_t OS::GetProgramCounter() {
return reinterpret_cast<uintptr_t>(
__builtin_extract_return_addr(__builtin_return_address(0)));
}
void OS::Print(const char* format, ...) {
va_list args;
va_start(args, format);
VFPrint(stdout, format, args);
va_end(args);
}
void OS::VFPrint(FILE* stream, const char* format, va_list args) {
vfprintf(stream, format, args);
fflush(stream);
}
char* OS::SCreate(Zone* zone, const char* format, ...) {
va_list args;
va_start(args, format);
char* buffer = VSCreate(zone, format, args);
va_end(args);
return buffer;
}
char* OS::VSCreate(Zone* zone, const char* format, va_list args) {
// Measure.
va_list measure_args;
va_copy(measure_args, args);
intptr_t len = Utils::VSNPrint(nullptr, 0, format, measure_args);
va_end(measure_args);
char* buffer;
if (zone != nullptr) {
buffer = zone->Alloc<char>(len + 1);
} else {
buffer = reinterpret_cast<char*>(malloc(len + 1));
}
ASSERT(buffer != nullptr);
// Print.
va_list print_args;
va_copy(print_args, args);
Utils::VSNPrint(buffer, len + 1, format, print_args);
va_end(print_args);
return buffer;
}
bool OS::StringToInt64(const char* str, int64_t* value) {
ASSERT(str != nullptr && strlen(str) > 0 && value != nullptr);
int32_t base = 10;
char* endptr;
int i = 0;
if (str[0] == '-') {
i = 1;
} else if (str[0] == '+') {
i = 1;
}
if ((str[i] == '0') && (str[i + 1] == 'x' || str[i + 1] == 'X') &&
(str[i + 2] != '\0')) {
base = 16;
}
errno = 0;
if (base == 16) {
// Unsigned 64-bit hexadecimal integer literals are allowed but
// immediately interpreted as signed 64-bit integers.
*value = static_cast<int64_t>(strtoull(str, &endptr, base));
} else {
*value = strtoll(str, &endptr, base);
}
return ((errno == 0) && (endptr != str) && (*endptr == 0));
}
void OS::RegisterCodeObservers() {
#ifndef PRODUCT
if (FLAG_generate_perf_events_symbols) {
CodeObservers::Register(new PerfCodeObserver);
}
if (FLAG_generate_perf_jitdump) {
CodeObservers::Register(new JitDumpCodeObserver);
}
#endif // !PRODUCT
}
void OS::PrintErr(const char* format, ...) {
va_list args;
va_start(args, format);
VFPrint(stderr, format, args);
va_end(args);
}
void OS::Init() {}
void OS::Cleanup() {}
void OS::PrepareToAbort() {}
void OS::Abort() {
PrepareToAbort();
abort();
}
void OS::Exit(int code) {
exit(code);
}
OS::BuildId OS::GetAppBuildId(const uint8_t* snapshot_instructions) {
// First return the build ID information from the instructions image if
// available.
const Image instructions_image(snapshot_instructions);
if (auto* const image_build_id = instructions_image.build_id()) {
return {instructions_image.build_id_length(), image_build_id};
}
const uint8_t* dso_base = GetAppDSOBase(snapshot_instructions);
const ElfW(Ehdr) & elf_header =
*reinterpret_cast<const ElfW(Ehdr)*>(dso_base);
const ElfW(Phdr)* const phdr_array =
reinterpret_cast<const ElfW(Phdr)*>(dso_base + elf_header.e_phoff);
for (intptr_t i = 0; i < elf_header.e_phnum; i++) {
const ElfW(Phdr) & header = phdr_array[i];
if (header.p_type != PT_NOTE) continue;
if ((header.p_flags & PF_R) != PF_R) continue;
const uint8_t* const note_addr = dso_base + header.p_vaddr;
const Elf32_Nhdr& note_header =
*reinterpret_cast<const Elf32_Nhdr*>(note_addr);
if (note_header.n_type != NT_GNU_BUILD_ID) continue;
const char* const note_contents =
reinterpret_cast<const char*>(note_addr + sizeof(Elf32_Nhdr));
// The note name contains the null terminator as well.
if (note_header.n_namesz != strlen(ELF_NOTE_GNU) + 1) continue;
if (strncmp(ELF_NOTE_GNU, note_contents, note_header.n_namesz) == 0) {
return {static_cast<intptr_t>(note_header.n_descsz),
reinterpret_cast<const uint8_t*>(note_contents +
note_header.n_namesz)};
}
}
return {0, nullptr};
}
} // namespace dart
#endif // defined(DART_HOST_OS_LINUX)