1// Copyright 2011 the V8 project authors. All rights reserved.
2// Redistribution and use in source and binary forms, with or without
3// modification, are permitted provided that the following conditions are
4// met:
5//
6//     * Redistributions of source code must retain the above copyright
7//       notice, this list of conditions and the following disclaimer.
8//     * Redistributions in binary form must reproduce the above
9//       copyright notice, this list of conditions and the following
10//       disclaimer in the documentation and/or other materials provided
11//       with the distribution.
12//     * Neither the name of Google Inc. nor the names of its
13//       contributors may be used to endorse or promote products derived
14//       from this software without specific prior written permission.
15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28#include "v8.h"
29
30#include "isolate.h"
31#include "bootstrapper.h"
32#include "debug.h"
33#include "deoptimizer.h"
34#include "heap-profiler.h"
35#include "hydrogen.h"
36#include "lithium-allocator.h"
37#include "log.h"
38#include "runtime-profiler.h"
39#include "serialize.h"
40
41namespace v8 {
42namespace internal {
43
44static Mutex* init_once_mutex = OS::CreateMutex();
45static bool init_once_called = false;
46
47bool V8::is_running_ = false;
48bool V8::has_been_setup_ = false;
49bool V8::has_been_disposed_ = false;
50bool V8::has_fatal_error_ = false;
51bool V8::use_crankshaft_ = true;
52
53
54bool V8::Initialize(Deserializer* des) {
55  InitializeOncePerProcess();
56
57  // The current thread may not yet had entered an isolate to run.
58  // Note the Isolate::Current() may be non-null because for various
59  // initialization purposes an initializing thread may be assigned an isolate
60  // but not actually enter it.
61  if (i::Isolate::CurrentPerIsolateThreadData() == NULL) {
62    i::Isolate::EnterDefaultIsolate();
63  }
64
65  ASSERT(i::Isolate::CurrentPerIsolateThreadData() != NULL);
66  ASSERT(i::Isolate::CurrentPerIsolateThreadData()->thread_id().Equals(
67           i::ThreadId::Current()));
68  ASSERT(i::Isolate::CurrentPerIsolateThreadData()->isolate() ==
69         i::Isolate::Current());
70
71  if (IsDead()) return false;
72
73  Isolate* isolate = Isolate::Current();
74  if (isolate->IsInitialized()) return true;
75
76  is_running_ = true;
77  has_been_setup_ = true;
78  has_fatal_error_ = false;
79  has_been_disposed_ = false;
80
81  return isolate->Init(des);
82}
83
84
85void V8::SetFatalError() {
86  is_running_ = false;
87  has_fatal_error_ = true;
88}
89
90
91void V8::TearDown() {
92  Isolate* isolate = Isolate::Current();
93  ASSERT(isolate->IsDefaultIsolate());
94
95  if (!has_been_setup_ || has_been_disposed_) return;
96  isolate->TearDown();
97
98  is_running_ = false;
99  has_been_disposed_ = true;
100}
101
102
103static uint32_t random_seed() {
104  if (FLAG_random_seed == 0) {
105    return random();
106  }
107  return FLAG_random_seed;
108}
109
110
111typedef struct {
112  uint32_t hi;
113  uint32_t lo;
114} random_state;
115
116
117// Random number generator using George Marsaglia's MWC algorithm.
118static uint32_t random_base(random_state *state) {
119  // Initialize seed using the system random(). If one of the seeds
120  // should ever become zero again, or if random() returns zero, we
121  // avoid getting stuck with zero bits in hi or lo by re-initializing
122  // them on demand.
123  if (state->hi == 0) state->hi = random_seed();
124  if (state->lo == 0) state->lo = random_seed();
125
126  // Mix the bits.
127  state->hi = 36969 * (state->hi & 0xFFFF) + (state->hi >> 16);
128  state->lo = 18273 * (state->lo & 0xFFFF) + (state->lo >> 16);
129  return (state->hi << 16) + (state->lo & 0xFFFF);
130}
131
132
133// Used by JavaScript APIs
134uint32_t V8::Random(Isolate* isolate) {
135  ASSERT(isolate == Isolate::Current());
136  // TODO(isolates): move lo and hi to isolate
137  static random_state state = {0, 0};
138  return random_base(&state);
139}
140
141
142// Used internally by the JIT and memory allocator for security
143// purposes. So, we keep a different state to prevent informations
144// leaks that could be used in an exploit.
145uint32_t V8::RandomPrivate(Isolate* isolate) {
146  ASSERT(isolate == Isolate::Current());
147  // TODO(isolates): move lo and hi to isolate
148  static random_state state = {0, 0};
149  return random_base(&state);
150}
151
152
153bool V8::IdleNotification() {
154  // Returning true tells the caller that there is no need to call
155  // IdleNotification again.
156  if (!FLAG_use_idle_notification) return true;
157
158  // Tell the heap that it may want to adjust.
159  return HEAP->IdleNotification();
160}
161
162
163// Use a union type to avoid type-aliasing optimizations in GCC.
164typedef union {
165  double double_value;
166  uint64_t uint64_t_value;
167} double_int_union;
168
169
170Object* V8::FillHeapNumberWithRandom(Object* heap_number, Isolate* isolate) {
171  uint64_t random_bits = Random(isolate);
172  // Make a double* from address (heap_number + sizeof(double)).
173  double_int_union* r = reinterpret_cast<double_int_union*>(
174      reinterpret_cast<char*>(heap_number) +
175      HeapNumber::kValueOffset - kHeapObjectTag);
176  // Convert 32 random bits to 0.(32 random bits) in a double
177  // by computing:
178  // ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
179  const double binary_million = 1048576.0;
180  r->double_value = binary_million;
181  r->uint64_t_value |=  random_bits;
182  r->double_value -= binary_million;
183
184  return heap_number;
185}
186
187
188void V8::InitializeOncePerProcess() {
189  ScopedLock lock(init_once_mutex);
190  if (init_once_called) return;
191  init_once_called = true;
192
193  // Setup the platform OS support.
194  OS::Setup();
195
196  use_crankshaft_ = FLAG_crankshaft;
197
198  if (Serializer::enabled()) {
199    use_crankshaft_ = false;
200  }
201
202  CPU::Setup();
203  if (!CPU::SupportsCrankshaft()) {
204    use_crankshaft_ = false;
205  }
206
207  RuntimeProfiler::GlobalSetup();
208
209  // Peephole optimization might interfere with deoptimization.
210  FLAG_peephole_optimization = !use_crankshaft_;
211}
212
213} }  // namespace v8::internal
214