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1 // Copyright 2012 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 "elements.h"
32 #include "bootstrapper.h"
33 #include "debug.h"
34 #include "deoptimizer.h"
35 #include "heap-profiler.h"
36 #include "hydrogen.h"
37 #include "lithium-allocator.h"
38 #include "log.h"
39 #include "once.h"
40 #include "platform.h"
41 #include "runtime-profiler.h"
42 #include "serialize.h"
43 #include "store-buffer.h"
44 
45 namespace v8 {
46 namespace internal {
47 
48 V8_DECLARE_ONCE(init_once);
49 
50 bool V8::is_running_ = false;
51 bool V8::has_been_set_up_ = false;
52 bool V8::has_been_disposed_ = false;
53 bool V8::has_fatal_error_ = false;
54 bool V8::use_crankshaft_ = true;
55 List<CallCompletedCallback>* V8::call_completed_callbacks_ = NULL;
56 
57 static LazyMutex entropy_mutex = LAZY_MUTEX_INITIALIZER;
58 
59 static EntropySource entropy_source;
60 
61 
Initialize(Deserializer * des)62 bool V8::Initialize(Deserializer* des) {
63   FlagList::EnforceFlagImplications();
64 
65   InitializeOncePerProcess();
66 
67   // The current thread may not yet had entered an isolate to run.
68   // Note the Isolate::Current() may be non-null because for various
69   // initialization purposes an initializing thread may be assigned an isolate
70   // but not actually enter it.
71   if (i::Isolate::CurrentPerIsolateThreadData() == NULL) {
72     i::Isolate::EnterDefaultIsolate();
73   }
74 
75   ASSERT(i::Isolate::CurrentPerIsolateThreadData() != NULL);
76   ASSERT(i::Isolate::CurrentPerIsolateThreadData()->thread_id().Equals(
77            i::ThreadId::Current()));
78   ASSERT(i::Isolate::CurrentPerIsolateThreadData()->isolate() ==
79          i::Isolate::Current());
80 
81   if (IsDead()) return false;
82 
83   Isolate* isolate = Isolate::Current();
84   if (isolate->IsInitialized()) return true;
85 
86   is_running_ = true;
87   has_been_set_up_ = true;
88   has_fatal_error_ = false;
89   has_been_disposed_ = false;
90 
91   return isolate->Init(des);
92 }
93 
94 
SetFatalError()95 void V8::SetFatalError() {
96   is_running_ = false;
97   has_fatal_error_ = true;
98 }
99 
100 
TearDown()101 void V8::TearDown() {
102   Isolate* isolate = Isolate::Current();
103   ASSERT(isolate->IsDefaultIsolate());
104 
105   if (!has_been_set_up_ || has_been_disposed_) return;
106   isolate->TearDown();
107 
108   is_running_ = false;
109   has_been_disposed_ = true;
110 
111   delete call_completed_callbacks_;
112   call_completed_callbacks_ = NULL;
113 }
114 
115 
seed_random(uint32_t * state)116 static void seed_random(uint32_t* state) {
117   for (int i = 0; i < 2; ++i) {
118     if (FLAG_random_seed != 0) {
119       state[i] = FLAG_random_seed;
120     } else if (entropy_source != NULL) {
121       uint32_t val;
122       ScopedLock lock(entropy_mutex.Pointer());
123       entropy_source(reinterpret_cast<unsigned char*>(&val), sizeof(uint32_t));
124       state[i] = val;
125     } else {
126       state[i] = random();
127     }
128   }
129 }
130 
131 
132 // Random number generator using George Marsaglia's MWC algorithm.
random_base(uint32_t * state)133 static uint32_t random_base(uint32_t* state) {
134   // Initialize seed using the system random().
135   // No non-zero seed will ever become zero again.
136   if (state[0] == 0) seed_random(state);
137 
138   // Mix the bits.  Never replaces state[i] with 0 if it is nonzero.
139   state[0] = 18273 * (state[0] & 0xFFFF) + (state[0] >> 16);
140   state[1] = 36969 * (state[1] & 0xFFFF) + (state[1] >> 16);
141 
142   return (state[0] << 14) + (state[1] & 0x3FFFF);
143 }
144 
145 
SetEntropySource(EntropySource source)146 void V8::SetEntropySource(EntropySource source) {
147   entropy_source = source;
148 }
149 
150 
SetReturnAddressLocationResolver(ReturnAddressLocationResolver resolver)151 void V8::SetReturnAddressLocationResolver(
152       ReturnAddressLocationResolver resolver) {
153   StackFrame::SetReturnAddressLocationResolver(resolver);
154 }
155 
156 
157 // Used by JavaScript APIs
Random(Context * context)158 uint32_t V8::Random(Context* context) {
159   ASSERT(context->IsGlobalContext());
160   ByteArray* seed = context->random_seed();
161   return random_base(reinterpret_cast<uint32_t*>(seed->GetDataStartAddress()));
162 }
163 
164 
165 // Used internally by the JIT and memory allocator for security
166 // purposes. So, we keep a different state to prevent informations
167 // leaks that could be used in an exploit.
RandomPrivate(Isolate * isolate)168 uint32_t V8::RandomPrivate(Isolate* isolate) {
169   ASSERT(isolate == Isolate::Current());
170   return random_base(isolate->private_random_seed());
171 }
172 
173 
IdleNotification(int hint)174 bool V8::IdleNotification(int hint) {
175   // Returning true tells the caller that there is no need to call
176   // IdleNotification again.
177   if (!FLAG_use_idle_notification) return true;
178 
179   // Tell the heap that it may want to adjust.
180   return HEAP->IdleNotification(hint);
181 }
182 
183 
AddCallCompletedCallback(CallCompletedCallback callback)184 void V8::AddCallCompletedCallback(CallCompletedCallback callback) {
185   if (call_completed_callbacks_ == NULL) {  // Lazy init.
186     call_completed_callbacks_ = new List<CallCompletedCallback>();
187   }
188   for (int i = 0; i < call_completed_callbacks_->length(); i++) {
189     if (callback == call_completed_callbacks_->at(i)) return;
190   }
191   call_completed_callbacks_->Add(callback);
192 }
193 
194 
RemoveCallCompletedCallback(CallCompletedCallback callback)195 void V8::RemoveCallCompletedCallback(CallCompletedCallback callback) {
196   if (call_completed_callbacks_ == NULL) return;
197   for (int i = 0; i < call_completed_callbacks_->length(); i++) {
198     if (callback == call_completed_callbacks_->at(i)) {
199       call_completed_callbacks_->Remove(i);
200     }
201   }
202 }
203 
204 
FireCallCompletedCallback(Isolate * isolate)205 void V8::FireCallCompletedCallback(Isolate* isolate) {
206   if (call_completed_callbacks_ == NULL) return;
207   HandleScopeImplementer* handle_scope_implementer =
208       isolate->handle_scope_implementer();
209   if (!handle_scope_implementer->CallDepthIsZero()) return;
210   // Fire callbacks.  Increase call depth to prevent recursive callbacks.
211   handle_scope_implementer->IncrementCallDepth();
212   for (int i = 0; i < call_completed_callbacks_->length(); i++) {
213     call_completed_callbacks_->at(i)();
214   }
215   handle_scope_implementer->DecrementCallDepth();
216 }
217 
218 
219 // Use a union type to avoid type-aliasing optimizations in GCC.
220 typedef union {
221   double double_value;
222   uint64_t uint64_t_value;
223 } double_int_union;
224 
225 
FillHeapNumberWithRandom(Object * heap_number,Context * context)226 Object* V8::FillHeapNumberWithRandom(Object* heap_number,
227                                      Context* context) {
228   double_int_union r;
229   uint64_t random_bits = Random(context);
230   // Convert 32 random bits to 0.(32 random bits) in a double
231   // by computing:
232   // ( 1.(20 0s)(32 random bits) x 2^20 ) - (1.0 x 2^20)).
233   static const double binary_million = 1048576.0;
234   r.double_value = binary_million;
235   r.uint64_t_value |= random_bits;
236   r.double_value -= binary_million;
237 
238   HeapNumber::cast(heap_number)->set_value(r.double_value);
239   return heap_number;
240 }
241 
InitializeOncePerProcessImpl()242 void V8::InitializeOncePerProcessImpl() {
243   // Set up the platform OS support.
244   OS::SetUp();
245 
246   use_crankshaft_ = FLAG_crankshaft;
247 
248   if (Serializer::enabled()) {
249     use_crankshaft_ = false;
250   }
251 
252   CPU::SetUp();
253   if (!CPU::SupportsCrankshaft()) {
254     use_crankshaft_ = false;
255   }
256 
257   OS::PostSetUp();
258 
259   RuntimeProfiler::GlobalSetup();
260 
261   ElementsAccessor::InitializeOncePerProcess();
262 
263   if (FLAG_stress_compaction) {
264     FLAG_force_marking_deque_overflows = true;
265     FLAG_gc_global = true;
266     FLAG_max_new_space_size = (1 << (kPageSizeBits - 10)) * 2;
267   }
268 
269   LOperand::SetUpCaches();
270 }
271 
InitializeOncePerProcess()272 void V8::InitializeOncePerProcess() {
273   CallOnce(&init_once, &InitializeOncePerProcessImpl);
274 }
275 
276 } }  // namespace v8::internal
277