text: // Copyright 2012 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "src/v8.h"
  
  #include <fstream>
  
  #include "src/api.h"
  #include "src/base/atomicops.h"
  #include "src/base/once.h"
  #include "src/base/platform/platform.h"
  #include "src/bootstrapper.h"
  #include "src/cpu-features.h"
  #include "src/debug/debug.h"
  #include "src/deoptimizer.h"
  #include "src/elements.h"
  #include "src/frames.h"
  #include "src/interface-descriptors.h"
  #include "src/isolate.h"
  #include "src/libsampler/sampler.h"
  #include "src/objects-inl.h"
  #include "src/profiler/heap-profiler.h"
  #include "src/reloc-info.h"
  #include "src/runtime-profiler.h"
  #include "src/simulator.h"
  #include "src/snapshot/natives.h"
  #include "src/snapshot/snapshot.h"
  #include "src/tracing/tracing-category-observer.h"
  #include "src/wasm/wasm-engine.h"
  
  namespace v8 {
  namespace internal {
  
  V8_DECLARE_ONCE(init_once);
  
  #ifdef V8_USE_EXTERNAL_STARTUP_DATA
  V8_DECLARE_ONCE(init_natives_once);
  V8_DECLARE_ONCE(init_snapshot_once);
  #endif
  
  v8::Platform* V8::platform_ = nullptr;
  
  bool V8::Initialize() {
    InitializeOncePerProcess();
    return true;
  }
  
  
  void V8::TearDown() {
    wasm::WasmEngine::GlobalTearDown();
  #if defined(USE_SIMULATOR)
    Simulator::GlobalTearDown();
  #endif
    CallDescriptors::TearDown();
    ElementsAccessor::TearDown();
    RegisteredExtension::UnregisterAll();
    FlagList::ResetAllFlags();  // Frees memory held by string arguments.
  }
  
  
  void V8::InitializeOncePerProcessImpl() {
    FlagList::EnforceFlagImplications();
  
    if (FLAG_predictable && FLAG_random_seed == 0) {
      // Avoid random seeds in predictable mode.
      FLAG_random_seed = 12347;
    }
  
    if (FLAG_stress_compaction) {
      FLAG_force_marking_deque_overflows = true;
      FLAG_gc_global = true;
      FLAG_max_semi_space_size = 1;
    }
  
    if (FLAG_trace_turbo) {
      // Create an empty file shared by the process (e.g. the wasm engine).
      std::ofstream(Isolate::GetTurboCfgFileName(nullptr).c_str(),
                    std::ios_base::trunc);
    }
  
    base::OS::Initialize(FLAG_hard_abort, FLAG_gc_fake_mmap);
  
    if (FLAG_random_seed) SetRandomMmapSeed(FLAG_random_seed);
  
    Isolate::InitializeOncePerProcess();
  
  #if defined(USE_SIMULATOR)
    Simulator::InitializeOncePerProcess();
  #endif
    CpuFeatures::Probe(false);
    ElementsAccessor::InitializeOncePerProcess();
    Bootstrapper::InitializeOncePerProcess();
    CallDescriptors::InitializeOncePerProcess();
    wasm::WasmEngine::InitializeOncePerProcess();
  }
  
  
  void V8::InitializeOncePerProcess() {
    base::CallOnce(&init_once, &InitializeOncePerProcessImpl);
  }
  
  
  void V8::InitializePlatform(v8::Platform* platform) {
    CHECK(!platform_);
    CHECK(platform);
    platform_ = platform;
    v8::base::SetPrintStackTrace(platform_->GetStackTracePrinter());
    v8::tracing::TracingCategoryObserver::SetUp();
  }
  
  
  void V8::ShutdownPlatform() {
    CHECK(platform_);
    v8::tracing::TracingCategoryObserver::TearDown();
    v8::base::SetPrintStackTrace(nullptr);
    platform_ = nullptr;
  }
  
  
  v8::Platform* V8::GetCurrentPlatform() {
    v8::Platform* platform = reinterpret_cast<v8::Platform*>(
        base::Relaxed_Load(reinterpret_cast<base::AtomicWord*>(&platform_)));
    DCHECK(platform);
    return platform;
  }
  
  void V8::SetPlatformForTesting(v8::Platform* platform) {
    base::Relaxed_Store(reinterpret_cast<base::AtomicWord*>(&platform_),
                        reinterpret_cast<base::AtomicWord>(platform));
  }
  
  void V8::SetNativesBlob(StartupData* natives_blob) {
  #ifdef V8_USE_EXTERNAL_STARTUP_DATA
    base::CallOnce(&init_natives_once, &SetNativesFromFile, natives_blob);
  #else
    UNREACHABLE();
  #endif
  }
  
  
  void V8::SetSnapshotBlob(StartupData* snapshot_blob) {
  #ifdef V8_USE_EXTERNAL_STARTUP_DATA
    base::CallOnce(&init_snapshot_once, &SetSnapshotFromFile, snapshot_blob);
  #else
    UNREACHABLE();
  #endif
  }
  }  // namespace internal
  
  // static
  double Platform::SystemClockTimeMillis() {
    return base::OS::TimeCurrentMillis();
  }
  }  // namespace v8
  