mozjs_sys 0.67.1

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "vtune/VTuneWrapper.h"

#include "mozilla/Sprintf.h"

#include "threading/LockGuard.h"
#include "threading/Mutex.h"
#include "vm/JSContext.h"
#include "vm/MutexIDs.h"
#include "vm/Realm.h"
#include "vm/Shape.h"

#ifdef MOZ_VTUNE

namespace js {
namespace vtune {

// VTune internals are not known to be threadsafe.
static Mutex* VTuneMutex = nullptr;

// Firefox must be launched from within VTune. Then the profiler
// status never changes, and we can avoid shared library checks.
static bool VTuneLoaded(false);

// Initialization is called from a single-threaded context.
bool Initialize() {
  VTuneMutex = js_new<Mutex>(mutexid::VTuneLock);
  if (!VTuneMutex) return false;

  // Load the VTune shared library, if present.
  int loaded = loadiJIT_Funcs();
  if (loaded == 1) VTuneLoaded = true;

  return true;
}

// Shutdown is called froma single-threaded context.
void Shutdown() {
  js_delete(VTuneMutex);
  VTuneMutex = nullptr;
}

bool IsProfilingActive() {
  // Checking VTuneLoaded guards against VTune internals attempting
  // to load the VTune library upon their invocation.
  return VTuneLoaded && iJIT_IsProfilingActive() == iJIT_SAMPLING_ON;
}

uint32_t GenerateUniqueMethodID() {
  // iJIT_GetNewMethodID() is explicitly not threadsafe.
  MOZ_ASSERT(VTuneMutex);
  LockGuard<Mutex> guard(*VTuneMutex);
  return (uint32_t)iJIT_GetNewMethodID();
}

static int SafeNotifyEvent(iJIT_JVM_EVENT event_type, void* data) {
  MOZ_ASSERT(VTuneMutex);
  LockGuard<Mutex> guard(*VTuneMutex);
  return iJIT_NotifyEvent(event_type, data);
}

// Stubs and trampolines are created on engine initialization and are never
// unloaded.
void MarkStub(const js::jit::JitCode* code, const char* name) {
  if (!IsProfilingActive()) return;

  iJIT_Method_Load_V2 method = {0};
  method.method_id = GenerateUniqueMethodID();
  method.method_name = const_cast<char*>(name);
  method.method_load_address = code->raw();
  method.method_size = code->instructionsSize();
  method.module_name = const_cast<char*>("jitstubs");

  int ok =
      SafeNotifyEvent(iJVM_EVENT_TYPE_METHOD_LOAD_FINISHED_V2, (void*)&method);
  if (ok != 1) printf("[!] VTune Integration: Failed to load method.\n");
}

void MarkRegExp(const js::jit::JitCode* code, bool match_only) {
  if (!IsProfilingActive()) return;

  iJIT_Method_Load_V2 method = {0};
  method.method_id = GenerateUniqueMethodID();
  method.method_load_address = code->raw();
  method.method_size = code->instructionsSize();

  if (match_only)
    method.method_name = const_cast<char*>("regexp (match-only)");
  else
    method.method_name = const_cast<char*>("regexp (normal)");

  method.module_name = const_cast<char*>("irregexp");

  int ok =
      SafeNotifyEvent(iJVM_EVENT_TYPE_METHOD_LOAD_FINISHED_V2, (void*)&method);
  if (ok != 1) printf("[!] VTune Integration: Failed to load method.\n");
}

void MarkScript(const js::jit::JitCode* code, JSScript* script,
                const char* module) {
  if (!IsProfilingActive()) return;

  iJIT_Method_Load_V2 method = {0};
  method.method_id = script->vtuneMethodID();
  method.method_load_address = code->raw();
  method.method_size = code->instructionsSize();
  method.module_name = const_cast<char*>(module);

  // Line numbers begin at 1, but columns begin at 0.
  // Text editors start at 1,1 so fixup is performed to match.
  char namebuf[512];
  SprintfLiteral(namebuf, "%s:%u:%u", script->filename(), script->lineno(),
                 script->column() + 1);

  method.method_name = &namebuf[0];

  int ok =
      SafeNotifyEvent(iJVM_EVENT_TYPE_METHOD_LOAD_FINISHED_V2, (void*)&method);
  if (ok != 1) printf("[!] VTune Integration: Failed to load method.\n");
}

void MarkWasm(unsigned methodId, const char* name, void* start,
              uintptr_t size) {
  if (!IsProfilingActive()) return;

  iJIT_Method_Load_V2 method = {0};
  method.method_id = methodId;
  method.method_name = const_cast<char*>(name);
  method.method_load_address = start;
  method.method_size = (unsigned)size;
  method.module_name = const_cast<char*>("wasm");

  int ok =
      SafeNotifyEvent(iJVM_EVENT_TYPE_METHOD_LOAD_FINISHED_V2, (void*)&method);
  if (ok != 1) printf("[!] VTune Integration: Failed to load method.\n");
}

void UnmarkCode(const js::jit::JitCode* code) {
  UnmarkBytes(code->raw(), (unsigned)code->instructionsSize());
}

void UnmarkBytes(void* bytes, unsigned size) {
  if (!IsProfilingActive()) return;

  // It appears that the method_id is not required for unloading.
  iJIT_Method_Load method = {0};
  method.method_load_address = bytes;
  method.method_size = size;

  // The iJVM_EVENT_TYPE_METHOD_UNLOAD_START event is undocumented.
  // VTune appears to happily accept unload events even for untracked JitCode.
  int ok = SafeNotifyEvent(iJVM_EVENT_TYPE_METHOD_UNLOAD_START, (void*)&method);

  // Assertions aren't reported in VTune: instead, they immediately end
  // profiling with no warning that a crash occurred. This can generate
  // misleading profiles. So instead, print out a message to stdout (which VTune
  // does not redirect).
  if (ok != 1) printf("[!] VTune Integration: Failed to unload method.\n");
}

}  // namespace vtune
}  // namespace js

#endif  // MOZ_VTUNE