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      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 #ifndef V8_ISOLATE_H_
     29 #define V8_ISOLATE_H_
     30 
     31 #include "../include/v8-debug.h"
     32 #include "allocation.h"
     33 #include "apiutils.h"
     34 #include "atomicops.h"
     35 #include "builtins.h"
     36 #include "contexts.h"
     37 #include "execution.h"
     38 #include "frames.h"
     39 #include "global-handles.h"
     40 #include "handles.h"
     41 #include "heap.h"
     42 #include "regexp-stack.h"
     43 #include "runtime-profiler.h"
     44 #include "runtime.h"
     45 #include "zone.h"
     46 
     47 namespace v8 {
     48 namespace internal {
     49 
     50 class AstSentinels;
     51 class Bootstrapper;
     52 class CodeGenerator;
     53 class CodeRange;
     54 class CompilationCache;
     55 class ContextSlotCache;
     56 class ContextSwitcher;
     57 class Counters;
     58 class CpuFeatures;
     59 class CpuProfiler;
     60 class DeoptimizerData;
     61 class Deserializer;
     62 class EmptyStatement;
     63 class ExternalReferenceTable;
     64 class Factory;
     65 class FunctionInfoListener;
     66 class HandleScopeImplementer;
     67 class HeapProfiler;
     68 class InlineRuntimeFunctionsTable;
     69 class NoAllocationStringAllocator;
     70 class PcToCodeCache;
     71 class PreallocatedMemoryThread;
     72 class ProducerHeapProfile;
     73 class RegExpStack;
     74 class SaveContext;
     75 class UnicodeCache;
     76 class StringInputBuffer;
     77 class StringTracker;
     78 class StubCache;
     79 class ThreadManager;
     80 class ThreadState;
     81 class ThreadVisitor;  // Defined in v8threads.h
     82 class VMState;
     83 
     84 // 'void function pointer', used to roundtrip the
     85 // ExternalReference::ExternalReferenceRedirector since we can not include
     86 // assembler.h, where it is defined, here.
     87 typedef void* ExternalReferenceRedirectorPointer();
     88 
     89 
     90 #ifdef ENABLE_DEBUGGER_SUPPORT
     91 class Debug;
     92 class Debugger;
     93 class DebuggerAgent;
     94 #endif
     95 
     96 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
     97     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
     98 class Redirection;
     99 class Simulator;
    100 #endif
    101 
    102 
    103 // Static indirection table for handles to constants.  If a frame
    104 // element represents a constant, the data contains an index into
    105 // this table of handles to the actual constants.
    106 // Static indirection table for handles to constants.  If a Result
    107 // represents a constant, the data contains an index into this table
    108 // of handles to the actual constants.
    109 typedef ZoneList<Handle<Object> > ZoneObjectList;
    110 
    111 #define RETURN_IF_SCHEDULED_EXCEPTION(isolate)    \
    112   if (isolate->has_scheduled_exception())         \
    113       return isolate->PromoteScheduledException()
    114 
    115 #define RETURN_IF_EMPTY_HANDLE_VALUE(isolate, call, value) \
    116   if (call.is_null()) {                                    \
    117     ASSERT(isolate->has_pending_exception());              \
    118     return value;                                          \
    119   }
    120 
    121 #define RETURN_IF_EMPTY_HANDLE(isolate, call)                       \
    122   RETURN_IF_EMPTY_HANDLE_VALUE(isolate, call, Failure::Exception())
    123 
    124 #define ISOLATE_ADDRESS_LIST(C)            \
    125   C(handler_address)                       \
    126   C(c_entry_fp_address)                    \
    127   C(context_address)                       \
    128   C(pending_exception_address)             \
    129   C(external_caught_exception_address)
    130 
    131 #ifdef ENABLE_LOGGING_AND_PROFILING
    132 #define ISOLATE_ADDRESS_LIST_PROF(C)       \
    133   C(js_entry_sp_address)
    134 #else
    135 #define ISOLATE_ADDRESS_LIST_PROF(C)
    136 #endif
    137 
    138 
    139 // Platform-independent, reliable thread identifier.
    140 class ThreadId {
    141  public:
    142   // Creates an invalid ThreadId.
    143   ThreadId() : id_(kInvalidId) {}
    144 
    145   // Returns ThreadId for current thread.
    146   static ThreadId Current() { return ThreadId(GetCurrentThreadId()); }
    147 
    148   // Returns invalid ThreadId (guaranteed not to be equal to any thread).
    149   static ThreadId Invalid() { return ThreadId(kInvalidId); }
    150 
    151   // Compares ThreadIds for equality.
    152   INLINE(bool Equals(const ThreadId& other) const) {
    153     return id_ == other.id_;
    154   }
    155 
    156   // Checks whether this ThreadId refers to any thread.
    157   INLINE(bool IsValid() const) {
    158     return id_ != kInvalidId;
    159   }
    160 
    161   // Converts ThreadId to an integer representation
    162   // (required for public API: V8::V8::GetCurrentThreadId).
    163   int ToInteger() const { return id_; }
    164 
    165   // Converts ThreadId to an integer representation
    166   // (required for public API: V8::V8::TerminateExecution).
    167   static ThreadId FromInteger(int id) { return ThreadId(id); }
    168 
    169  private:
    170   static const int kInvalidId = -1;
    171 
    172   explicit ThreadId(int id) : id_(id) {}
    173 
    174   static int AllocateThreadId();
    175 
    176   static int GetCurrentThreadId();
    177 
    178   int id_;
    179 
    180   static Atomic32 highest_thread_id_;
    181 
    182   friend class Isolate;
    183 };
    184 
    185 
    186 class ThreadLocalTop BASE_EMBEDDED {
    187  public:
    188   // Does early low-level initialization that does not depend on the
    189   // isolate being present.
    190   ThreadLocalTop();
    191 
    192   // Initialize the thread data.
    193   void Initialize();
    194 
    195   // Get the top C++ try catch handler or NULL if none are registered.
    196   //
    197   // This method is not guarenteed to return an address that can be
    198   // used for comparison with addresses into the JS stack.  If such an
    199   // address is needed, use try_catch_handler_address.
    200   v8::TryCatch* TryCatchHandler();
    201 
    202   // Get the address of the top C++ try catch handler or NULL if
    203   // none are registered.
    204   //
    205   // This method always returns an address that can be compared to
    206   // pointers into the JavaScript stack.  When running on actual
    207   // hardware, try_catch_handler_address and TryCatchHandler return
    208   // the same pointer.  When running on a simulator with a separate JS
    209   // stack, try_catch_handler_address returns a JS stack address that
    210   // corresponds to the place on the JS stack where the C++ handler
    211   // would have been if the stack were not separate.
    212   inline Address try_catch_handler_address() {
    213     return try_catch_handler_address_;
    214   }
    215 
    216   // Set the address of the top C++ try catch handler.
    217   inline void set_try_catch_handler_address(Address address) {
    218     try_catch_handler_address_ = address;
    219   }
    220 
    221   void Free() {
    222     ASSERT(!has_pending_message_);
    223     ASSERT(!external_caught_exception_);
    224     ASSERT(try_catch_handler_address_ == NULL);
    225   }
    226 
    227   // The context where the current execution method is created and for variable
    228   // lookups.
    229   Context* context_;
    230   ThreadId thread_id_;
    231   MaybeObject* pending_exception_;
    232   bool has_pending_message_;
    233   Object* pending_message_obj_;
    234   Script* pending_message_script_;
    235   int pending_message_start_pos_;
    236   int pending_message_end_pos_;
    237   // Use a separate value for scheduled exceptions to preserve the
    238   // invariants that hold about pending_exception.  We may want to
    239   // unify them later.
    240   MaybeObject* scheduled_exception_;
    241   bool external_caught_exception_;
    242   SaveContext* save_context_;
    243   v8::TryCatch* catcher_;
    244 
    245   // Stack.
    246   Address c_entry_fp_;  // the frame pointer of the top c entry frame
    247   Address handler_;   // try-blocks are chained through the stack
    248 
    249 #ifdef USE_SIMULATOR
    250 #if defined(V8_TARGET_ARCH_ARM) || defined(V8_TARGET_ARCH_MIPS)
    251   Simulator* simulator_;
    252 #endif
    253 #endif  // USE_SIMULATOR
    254 
    255 #ifdef ENABLE_LOGGING_AND_PROFILING
    256   Address js_entry_sp_;  // the stack pointer of the bottom js entry frame
    257   Address external_callback_;  // the external callback we're currently in
    258 #endif
    259 
    260 #ifdef ENABLE_VMSTATE_TRACKING
    261   StateTag current_vm_state_;
    262 #endif
    263 
    264   // Generated code scratch locations.
    265   int32_t formal_count_;
    266 
    267   // Call back function to report unsafe JS accesses.
    268   v8::FailedAccessCheckCallback failed_access_check_callback_;
    269 
    270   // Whether out of memory exceptions should be ignored.
    271   bool ignore_out_of_memory_;
    272 
    273  private:
    274   void InitializeInternal();
    275 
    276   Address try_catch_handler_address_;
    277 };
    278 
    279 #if defined(V8_TARGET_ARCH_ARM) || defined(V8_TARGET_ARCH_MIPS)
    280 
    281 #define ISOLATE_PLATFORM_INIT_LIST(V)                                          \
    282   /* VirtualFrame::SpilledScope state */                                       \
    283   V(bool, is_virtual_frame_in_spilled_scope, false)                            \
    284   /* CodeGenerator::EmitNamedStore state */                                    \
    285   V(int, inlined_write_barrier_size, -1)
    286 
    287 #if !defined(__arm__) && !defined(__mips__)
    288 class HashMap;
    289 #endif
    290 
    291 #else
    292 
    293 #define ISOLATE_PLATFORM_INIT_LIST(V)
    294 
    295 #endif
    296 
    297 #ifdef ENABLE_DEBUGGER_SUPPORT
    298 
    299 #define ISOLATE_DEBUGGER_INIT_LIST(V)                                          \
    300   V(uint64_t, enabled_cpu_features, 0)                                         \
    301   V(v8::Debug::EventCallback, debug_event_callback, NULL)                      \
    302   V(DebuggerAgent*, debugger_agent_instance, NULL)
    303 #else
    304 
    305 #define ISOLATE_DEBUGGER_INIT_LIST(V)
    306 
    307 #endif
    308 
    309 #ifdef DEBUG
    310 
    311 #define ISOLATE_INIT_DEBUG_ARRAY_LIST(V)                                       \
    312   V(CommentStatistic, paged_space_comments_statistics,                         \
    313       CommentStatistic::kMaxComments + 1)
    314 #else
    315 
    316 #define ISOLATE_INIT_DEBUG_ARRAY_LIST(V)
    317 
    318 #endif
    319 
    320 #ifdef ENABLE_LOGGING_AND_PROFILING
    321 
    322 #define ISOLATE_LOGGING_INIT_LIST(V)                                           \
    323   V(CpuProfiler*, cpu_profiler, NULL)                                          \
    324   V(HeapProfiler*, heap_profiler, NULL)
    325 
    326 #else
    327 
    328 #define ISOLATE_LOGGING_INIT_LIST(V)
    329 
    330 #endif
    331 
    332 #define ISOLATE_INIT_ARRAY_LIST(V)                                             \
    333   /* SerializerDeserializer state. */                                          \
    334   V(Object*, serialize_partial_snapshot_cache, kPartialSnapshotCacheCapacity)  \
    335   V(int, jsregexp_static_offsets_vector, kJSRegexpStaticOffsetsVectorSize)     \
    336   V(int, bad_char_shift_table, kUC16AlphabetSize)                              \
    337   V(int, good_suffix_shift_table, (kBMMaxShift + 1))                           \
    338   V(int, suffix_table, (kBMMaxShift + 1))                                      \
    339   ISOLATE_INIT_DEBUG_ARRAY_LIST(V)
    340 
    341 typedef List<HeapObject*, PreallocatedStorage> DebugObjectCache;
    342 
    343 #define ISOLATE_INIT_LIST(V)                                                   \
    344   /* AssertNoZoneAllocation state. */                                          \
    345   V(bool, zone_allow_allocation, true)                                         \
    346   /* SerializerDeserializer state. */                                          \
    347   V(int, serialize_partial_snapshot_cache_length, 0)                           \
    348   /* Assembler state. */                                                       \
    349   /* A previously allocated buffer of kMinimalBufferSize bytes, or NULL. */    \
    350   V(byte*, assembler_spare_buffer, NULL)                                       \
    351   V(FatalErrorCallback, exception_behavior, NULL)                              \
    352   V(v8::Debug::MessageHandler, message_handler, NULL)                          \
    353   /* To distinguish the function templates, so that we can find them in the */ \
    354   /* function cache of the global context. */                                  \
    355   V(int, next_serial_number, 0)                                                \
    356   V(ExternalReferenceRedirectorPointer*, external_reference_redirector, NULL)  \
    357   V(bool, always_allow_natives_syntax, false)                                  \
    358   /* Part of the state of liveedit. */                                         \
    359   V(FunctionInfoListener*, active_function_info_listener, NULL)                \
    360   /* State for Relocatable. */                                                 \
    361   V(Relocatable*, relocatable_top, NULL)                                       \
    362   /* State for CodeEntry in profile-generator. */                              \
    363   V(CodeGenerator*, current_code_generator, NULL)                              \
    364   V(bool, jump_target_compiling_deferred_code, false)                          \
    365   V(DebugObjectCache*, string_stream_debug_object_cache, NULL)                 \
    366   V(Object*, string_stream_current_security_token, NULL)                       \
    367   /* TODO(isolates): Release this on destruction? */                           \
    368   V(int*, irregexp_interpreter_backtrack_stack_cache, NULL)                    \
    369   /* Serializer state. */                                                      \
    370   V(ExternalReferenceTable*, external_reference_table, NULL)                   \
    371   /* AstNode state. */                                                         \
    372   V(unsigned, ast_node_id, 0)                                                  \
    373   V(unsigned, ast_node_count, 0)                                               \
    374   /* SafeStackFrameIterator activations count. */                              \
    375   V(int, safe_stack_iterator_counter, 0)                                       \
    376   ISOLATE_PLATFORM_INIT_LIST(V)                                                \
    377   ISOLATE_LOGGING_INIT_LIST(V)                                                 \
    378   ISOLATE_DEBUGGER_INIT_LIST(V)
    379 
    380 class Isolate {
    381   // These forward declarations are required to make the friend declarations in
    382   // PerIsolateThreadData work on some older versions of gcc.
    383   class ThreadDataTable;
    384   class EntryStackItem;
    385  public:
    386   ~Isolate();
    387 
    388   // A thread has a PerIsolateThreadData instance for each isolate that it has
    389   // entered. That instance is allocated when the isolate is initially entered
    390   // and reused on subsequent entries.
    391   class PerIsolateThreadData {
    392    public:
    393     PerIsolateThreadData(Isolate* isolate, ThreadId thread_id)
    394         : isolate_(isolate),
    395           thread_id_(thread_id),
    396           stack_limit_(0),
    397           thread_state_(NULL),
    398 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
    399     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
    400           simulator_(NULL),
    401 #endif
    402           next_(NULL),
    403           prev_(NULL) { }
    404     Isolate* isolate() const { return isolate_; }
    405     ThreadId thread_id() const { return thread_id_; }
    406     void set_stack_limit(uintptr_t value) { stack_limit_ = value; }
    407     uintptr_t stack_limit() const { return stack_limit_; }
    408     ThreadState* thread_state() const { return thread_state_; }
    409     void set_thread_state(ThreadState* value) { thread_state_ = value; }
    410 
    411 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
    412     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
    413     Simulator* simulator() const { return simulator_; }
    414     void set_simulator(Simulator* simulator) {
    415       simulator_ = simulator;
    416     }
    417 #endif
    418 
    419     bool Matches(Isolate* isolate, ThreadId thread_id) const {
    420       return isolate_ == isolate && thread_id_.Equals(thread_id);
    421     }
    422 
    423    private:
    424     Isolate* isolate_;
    425     ThreadId thread_id_;
    426     uintptr_t stack_limit_;
    427     ThreadState* thread_state_;
    428 
    429 #if !defined(__arm__) && defined(V8_TARGET_ARCH_ARM) || \
    430     !defined(__mips__) && defined(V8_TARGET_ARCH_MIPS)
    431     Simulator* simulator_;
    432 #endif
    433 
    434     PerIsolateThreadData* next_;
    435     PerIsolateThreadData* prev_;
    436 
    437     friend class Isolate;
    438     friend class ThreadDataTable;
    439     friend class EntryStackItem;
    440 
    441     DISALLOW_COPY_AND_ASSIGN(PerIsolateThreadData);
    442   };
    443 
    444 
    445   enum AddressId {
    446 #define C(name) k_##name,
    447     ISOLATE_ADDRESS_LIST(C)
    448     ISOLATE_ADDRESS_LIST_PROF(C)
    449 #undef C
    450     k_isolate_address_count
    451   };
    452 
    453   // Returns the PerIsolateThreadData for the current thread (or NULL if one is
    454   // not currently set).
    455   static PerIsolateThreadData* CurrentPerIsolateThreadData() {
    456     return reinterpret_cast<PerIsolateThreadData*>(
    457         Thread::GetThreadLocal(per_isolate_thread_data_key_));
    458   }
    459 
    460   // Returns the isolate inside which the current thread is running.
    461   INLINE(static Isolate* Current()) {
    462     Isolate* isolate = reinterpret_cast<Isolate*>(
    463         Thread::GetExistingThreadLocal(isolate_key_));
    464     ASSERT(isolate != NULL);
    465     return isolate;
    466   }
    467 
    468   INLINE(static Isolate* UncheckedCurrent()) {
    469     return reinterpret_cast<Isolate*>(Thread::GetThreadLocal(isolate_key_));
    470   }
    471 
    472   // Usually called by Init(), but can be called early e.g. to allow
    473   // testing components that require logging but not the whole
    474   // isolate.
    475   //
    476   // Safe to call more than once.
    477   void InitializeLoggingAndCounters();
    478 
    479   bool Init(Deserializer* des);
    480 
    481   bool IsInitialized() { return state_ == INITIALIZED; }
    482 
    483   // True if at least one thread Enter'ed this isolate.
    484   bool IsInUse() { return entry_stack_ != NULL; }
    485 
    486   // Destroys the non-default isolates.
    487   // Sets default isolate into "has_been_disposed" state rather then destroying,
    488   // for legacy API reasons.
    489   void TearDown();
    490 
    491   bool IsDefaultIsolate() const { return this == default_isolate_; }
    492 
    493   // Ensures that process-wide resources and the default isolate have been
    494   // allocated. It is only necessary to call this method in rare casses, for
    495   // example if you are using V8 from within the body of a static initializer.
    496   // Safe to call multiple times.
    497   static void EnsureDefaultIsolate();
    498 
    499   // Get the debugger from the default isolate. Preinitializes the
    500   // default isolate if needed.
    501   static Debugger* GetDefaultIsolateDebugger();
    502 
    503   // Get the stack guard from the default isolate. Preinitializes the
    504   // default isolate if needed.
    505   static StackGuard* GetDefaultIsolateStackGuard();
    506 
    507   // Returns the key used to store the pointer to the current isolate.
    508   // Used internally for V8 threads that do not execute JavaScript but still
    509   // are part of the domain of an isolate (like the context switcher).
    510   static Thread::LocalStorageKey isolate_key() {
    511     return isolate_key_;
    512   }
    513 
    514   // Returns the key used to store process-wide thread IDs.
    515   static Thread::LocalStorageKey thread_id_key() {
    516     return thread_id_key_;
    517   }
    518 
    519   // If a client attempts to create a Locker without specifying an isolate,
    520   // we assume that the client is using legacy behavior. Set up the current
    521   // thread to be inside the implicit isolate (or fail a check if we have
    522   // switched to non-legacy behavior).
    523   static void EnterDefaultIsolate();
    524 
    525   // Mutex for serializing access to break control structures.
    526   Mutex* break_access() { return break_access_; }
    527 
    528   // Mutex for serializing access to debugger.
    529   Mutex* debugger_access() { return debugger_access_; }
    530 
    531   Address get_address_from_id(AddressId id);
    532 
    533   // Access to top context (where the current function object was created).
    534   Context* context() { return thread_local_top_.context_; }
    535   void set_context(Context* context) {
    536     thread_local_top_.context_ = context;
    537   }
    538   Context** context_address() { return &thread_local_top_.context_; }
    539 
    540   SaveContext* save_context() {return thread_local_top_.save_context_; }
    541   void set_save_context(SaveContext* save) {
    542     thread_local_top_.save_context_ = save;
    543   }
    544 
    545   // Access to current thread id.
    546   ThreadId thread_id() { return thread_local_top_.thread_id_; }
    547   void set_thread_id(ThreadId id) { thread_local_top_.thread_id_ = id; }
    548 
    549   // Interface to pending exception.
    550   MaybeObject* pending_exception() {
    551     ASSERT(has_pending_exception());
    552     return thread_local_top_.pending_exception_;
    553   }
    554   bool external_caught_exception() {
    555     return thread_local_top_.external_caught_exception_;
    556   }
    557   void set_external_caught_exception(bool value) {
    558     thread_local_top_.external_caught_exception_ = value;
    559   }
    560   void set_pending_exception(MaybeObject* exception) {
    561     thread_local_top_.pending_exception_ = exception;
    562   }
    563   void clear_pending_exception() {
    564     thread_local_top_.pending_exception_ = heap_.the_hole_value();
    565   }
    566   MaybeObject** pending_exception_address() {
    567     return &thread_local_top_.pending_exception_;
    568   }
    569   bool has_pending_exception() {
    570     return !thread_local_top_.pending_exception_->IsTheHole();
    571   }
    572   void clear_pending_message() {
    573     thread_local_top_.has_pending_message_ = false;
    574     thread_local_top_.pending_message_obj_ = heap_.the_hole_value();
    575     thread_local_top_.pending_message_script_ = NULL;
    576   }
    577   v8::TryCatch* try_catch_handler() {
    578     return thread_local_top_.TryCatchHandler();
    579   }
    580   Address try_catch_handler_address() {
    581     return thread_local_top_.try_catch_handler_address();
    582   }
    583   bool* external_caught_exception_address() {
    584     return &thread_local_top_.external_caught_exception_;
    585   }
    586   v8::TryCatch* catcher() {
    587     return thread_local_top_.catcher_;
    588   }
    589   void set_catcher(v8::TryCatch* catcher) {
    590     thread_local_top_.catcher_ = catcher;
    591   }
    592 
    593   MaybeObject** scheduled_exception_address() {
    594     return &thread_local_top_.scheduled_exception_;
    595   }
    596   MaybeObject* scheduled_exception() {
    597     ASSERT(has_scheduled_exception());
    598     return thread_local_top_.scheduled_exception_;
    599   }
    600   bool has_scheduled_exception() {
    601     return !thread_local_top_.scheduled_exception_->IsTheHole();
    602   }
    603   void clear_scheduled_exception() {
    604     thread_local_top_.scheduled_exception_ = heap_.the_hole_value();
    605   }
    606 
    607   bool IsExternallyCaught();
    608 
    609   bool is_catchable_by_javascript(MaybeObject* exception) {
    610     return (exception != Failure::OutOfMemoryException()) &&
    611         (exception != heap()->termination_exception());
    612   }
    613 
    614   // JS execution stack (see frames.h).
    615   static Address c_entry_fp(ThreadLocalTop* thread) {
    616     return thread->c_entry_fp_;
    617   }
    618   static Address handler(ThreadLocalTop* thread) { return thread->handler_; }
    619 
    620   inline Address* c_entry_fp_address() {
    621     return &thread_local_top_.c_entry_fp_;
    622   }
    623   inline Address* handler_address() { return &thread_local_top_.handler_; }
    624 
    625 #ifdef ENABLE_LOGGING_AND_PROFILING
    626   // Bottom JS entry (see StackTracer::Trace in log.cc).
    627   static Address js_entry_sp(ThreadLocalTop* thread) {
    628     return thread->js_entry_sp_;
    629   }
    630   inline Address* js_entry_sp_address() {
    631     return &thread_local_top_.js_entry_sp_;
    632   }
    633 #endif
    634 
    635   // Generated code scratch locations.
    636   void* formal_count_address() { return &thread_local_top_.formal_count_; }
    637 
    638   // Returns the global object of the current context. It could be
    639   // a builtin object, or a js global object.
    640   Handle<GlobalObject> global() {
    641     return Handle<GlobalObject>(context()->global());
    642   }
    643 
    644   // Returns the global proxy object of the current context.
    645   Object* global_proxy() {
    646     return context()->global_proxy();
    647   }
    648 
    649   Handle<JSBuiltinsObject> js_builtins_object() {
    650     return Handle<JSBuiltinsObject>(thread_local_top_.context_->builtins());
    651   }
    652 
    653   static int ArchiveSpacePerThread() { return sizeof(ThreadLocalTop); }
    654   void FreeThreadResources() { thread_local_top_.Free(); }
    655 
    656   // This method is called by the api after operations that may throw
    657   // exceptions.  If an exception was thrown and not handled by an external
    658   // handler the exception is scheduled to be rethrown when we return to running
    659   // JavaScript code.  If an exception is scheduled true is returned.
    660   bool OptionalRescheduleException(bool is_bottom_call);
    661 
    662   class ExceptionScope {
    663    public:
    664     explicit ExceptionScope(Isolate* isolate) :
    665       // Scope currently can only be used for regular exceptions, not
    666       // failures like OOM or termination exception.
    667       isolate_(isolate),
    668       pending_exception_(isolate_->pending_exception()->ToObjectUnchecked()),
    669       catcher_(isolate_->catcher())
    670     { }
    671 
    672     ~ExceptionScope() {
    673       isolate_->set_catcher(catcher_);
    674       isolate_->set_pending_exception(*pending_exception_);
    675     }
    676 
    677    private:
    678     Isolate* isolate_;
    679     Handle<Object> pending_exception_;
    680     v8::TryCatch* catcher_;
    681   };
    682 
    683   void SetCaptureStackTraceForUncaughtExceptions(
    684       bool capture,
    685       int frame_limit,
    686       StackTrace::StackTraceOptions options);
    687 
    688   // Tells whether the current context has experienced an out of memory
    689   // exception.
    690   bool is_out_of_memory();
    691   bool ignore_out_of_memory() {
    692     return thread_local_top_.ignore_out_of_memory_;
    693   }
    694   void set_ignore_out_of_memory(bool value) {
    695     thread_local_top_.ignore_out_of_memory_ = value;
    696   }
    697 
    698   void PrintCurrentStackTrace(FILE* out);
    699   void PrintStackTrace(FILE* out, char* thread_data);
    700   void PrintStack(StringStream* accumulator);
    701   void PrintStack();
    702   Handle<String> StackTraceString();
    703   Handle<JSArray> CaptureCurrentStackTrace(
    704       int frame_limit,
    705       StackTrace::StackTraceOptions options);
    706 
    707   // Returns if the top context may access the given global object. If
    708   // the result is false, the pending exception is guaranteed to be
    709   // set.
    710   bool MayNamedAccess(JSObject* receiver,
    711                       Object* key,
    712                       v8::AccessType type);
    713   bool MayIndexedAccess(JSObject* receiver,
    714                         uint32_t index,
    715                         v8::AccessType type);
    716 
    717   void SetFailedAccessCheckCallback(v8::FailedAccessCheckCallback callback);
    718   void ReportFailedAccessCheck(JSObject* receiver, v8::AccessType type);
    719 
    720   // Exception throwing support. The caller should use the result
    721   // of Throw() as its return value.
    722   Failure* Throw(Object* exception, MessageLocation* location = NULL);
    723   // Re-throw an exception.  This involves no error reporting since
    724   // error reporting was handled when the exception was thrown
    725   // originally.
    726   Failure* ReThrow(MaybeObject* exception, MessageLocation* location = NULL);
    727   void ScheduleThrow(Object* exception);
    728   void ReportPendingMessages();
    729   Failure* ThrowIllegalOperation();
    730 
    731   // Promote a scheduled exception to pending. Asserts has_scheduled_exception.
    732   Failure* PromoteScheduledException();
    733   void DoThrow(MaybeObject* exception, MessageLocation* location);
    734   // Checks if exception should be reported and finds out if it's
    735   // caught externally.
    736   bool ShouldReportException(bool* can_be_caught_externally,
    737                              bool catchable_by_javascript);
    738 
    739   // Attempts to compute the current source location, storing the
    740   // result in the target out parameter.
    741   void ComputeLocation(MessageLocation* target);
    742 
    743   // Override command line flag.
    744   void TraceException(bool flag);
    745 
    746   // Out of resource exception helpers.
    747   Failure* StackOverflow();
    748   Failure* TerminateExecution();
    749 
    750   // Administration
    751   void Iterate(ObjectVisitor* v);
    752   void Iterate(ObjectVisitor* v, ThreadLocalTop* t);
    753   char* Iterate(ObjectVisitor* v, char* t);
    754   void IterateThread(ThreadVisitor* v);
    755   void IterateThread(ThreadVisitor* v, char* t);
    756 
    757 
    758   // Returns the current global context.
    759   Handle<Context> global_context();
    760 
    761   // Returns the global context of the calling JavaScript code.  That
    762   // is, the global context of the top-most JavaScript frame.
    763   Handle<Context> GetCallingGlobalContext();
    764 
    765   void RegisterTryCatchHandler(v8::TryCatch* that);
    766   void UnregisterTryCatchHandler(v8::TryCatch* that);
    767 
    768   char* ArchiveThread(char* to);
    769   char* RestoreThread(char* from);
    770 
    771   static const char* const kStackOverflowMessage;
    772 
    773   static const int kUC16AlphabetSize = 256;  // See StringSearchBase.
    774   static const int kBMMaxShift = 250;        // See StringSearchBase.
    775 
    776   // Accessors.
    777 #define GLOBAL_ACCESSOR(type, name, initialvalue)                       \
    778   inline type name() const {                                            \
    779     ASSERT(OFFSET_OF(Isolate, name##_) == name##_debug_offset_);        \
    780     return name##_;                                                     \
    781   }                                                                     \
    782   inline void set_##name(type value) {                                  \
    783     ASSERT(OFFSET_OF(Isolate, name##_) == name##_debug_offset_);        \
    784     name##_ = value;                                                    \
    785   }
    786   ISOLATE_INIT_LIST(GLOBAL_ACCESSOR)
    787 #undef GLOBAL_ACCESSOR
    788 
    789 #define GLOBAL_ARRAY_ACCESSOR(type, name, length)                       \
    790   inline type* name() {                                                 \
    791     ASSERT(OFFSET_OF(Isolate, name##_) == name##_debug_offset_);        \
    792     return &(name##_)[0];                                               \
    793   }
    794   ISOLATE_INIT_ARRAY_LIST(GLOBAL_ARRAY_ACCESSOR)
    795 #undef GLOBAL_ARRAY_ACCESSOR
    796 
    797 #define GLOBAL_CONTEXT_FIELD_ACCESSOR(index, type, name)      \
    798   Handle<type> name() {                                       \
    799     return Handle<type>(context()->global_context()->name()); \
    800   }
    801   GLOBAL_CONTEXT_FIELDS(GLOBAL_CONTEXT_FIELD_ACCESSOR)
    802 #undef GLOBAL_CONTEXT_FIELD_ACCESSOR
    803 
    804   Bootstrapper* bootstrapper() { return bootstrapper_; }
    805   Counters* counters() {
    806     // Call InitializeLoggingAndCounters() if logging is needed before
    807     // the isolate is fully initialized.
    808     ASSERT(counters_ != NULL);
    809     return counters_;
    810   }
    811   CodeRange* code_range() { return code_range_; }
    812   RuntimeProfiler* runtime_profiler() { return runtime_profiler_; }
    813   CompilationCache* compilation_cache() { return compilation_cache_; }
    814   Logger* logger() {
    815     // Call InitializeLoggingAndCounters() if logging is needed before
    816     // the isolate is fully initialized.
    817     ASSERT(logger_ != NULL);
    818     return logger_;
    819   }
    820   StackGuard* stack_guard() { return &stack_guard_; }
    821   Heap* heap() { return &heap_; }
    822   StatsTable* stats_table();
    823   StubCache* stub_cache() { return stub_cache_; }
    824   DeoptimizerData* deoptimizer_data() { return deoptimizer_data_; }
    825   ThreadLocalTop* thread_local_top() { return &thread_local_top_; }
    826 
    827   TranscendentalCache* transcendental_cache() const {
    828     return transcendental_cache_;
    829   }
    830 
    831   MemoryAllocator* memory_allocator() {
    832     return memory_allocator_;
    833   }
    834 
    835   KeyedLookupCache* keyed_lookup_cache() {
    836     return keyed_lookup_cache_;
    837   }
    838 
    839   ContextSlotCache* context_slot_cache() {
    840     return context_slot_cache_;
    841   }
    842 
    843   DescriptorLookupCache* descriptor_lookup_cache() {
    844     return descriptor_lookup_cache_;
    845   }
    846 
    847   v8::ImplementationUtilities::HandleScopeData* handle_scope_data() {
    848     return &handle_scope_data_;
    849   }
    850   HandleScopeImplementer* handle_scope_implementer() {
    851     ASSERT(handle_scope_implementer_);
    852     return handle_scope_implementer_;
    853   }
    854   Zone* zone() { return &zone_; }
    855 
    856   UnicodeCache* unicode_cache() {
    857     return unicode_cache_;
    858   }
    859 
    860   PcToCodeCache* pc_to_code_cache() { return pc_to_code_cache_; }
    861 
    862   StringInputBuffer* write_input_buffer() { return write_input_buffer_; }
    863 
    864   GlobalHandles* global_handles() { return global_handles_; }
    865 
    866   ThreadManager* thread_manager() { return thread_manager_; }
    867 
    868   ContextSwitcher* context_switcher() { return context_switcher_; }
    869 
    870   void set_context_switcher(ContextSwitcher* switcher) {
    871     context_switcher_ = switcher;
    872   }
    873 
    874   StringTracker* string_tracker() { return string_tracker_; }
    875 
    876   unibrow::Mapping<unibrow::Ecma262UnCanonicalize>* jsregexp_uncanonicalize() {
    877     return &jsregexp_uncanonicalize_;
    878   }
    879 
    880   unibrow::Mapping<unibrow::CanonicalizationRange>* jsregexp_canonrange() {
    881     return &jsregexp_canonrange_;
    882   }
    883 
    884   StringInputBuffer* objects_string_compare_buffer_a() {
    885     return &objects_string_compare_buffer_a_;
    886   }
    887 
    888   StringInputBuffer* objects_string_compare_buffer_b() {
    889     return &objects_string_compare_buffer_b_;
    890   }
    891 
    892   StaticResource<StringInputBuffer>* objects_string_input_buffer() {
    893     return &objects_string_input_buffer_;
    894   }
    895 
    896   AstSentinels* ast_sentinels() { return ast_sentinels_; }
    897 
    898   RuntimeState* runtime_state() { return &runtime_state_; }
    899 
    900   StringInputBuffer* liveedit_compare_substrings_buf1() {
    901     return &liveedit_compare_substrings_buf1_;
    902   }
    903 
    904   StringInputBuffer* liveedit_compare_substrings_buf2() {
    905     return &liveedit_compare_substrings_buf2_;
    906   }
    907 
    908   StaticResource<SafeStringInputBuffer>* compiler_safe_string_input_buffer() {
    909     return &compiler_safe_string_input_buffer_;
    910   }
    911 
    912   Builtins* builtins() { return &builtins_; }
    913 
    914   unibrow::Mapping<unibrow::Ecma262Canonicalize>*
    915       regexp_macro_assembler_canonicalize() {
    916     return &regexp_macro_assembler_canonicalize_;
    917   }
    918 
    919   RegExpStack* regexp_stack() { return regexp_stack_; }
    920 
    921   unibrow::Mapping<unibrow::Ecma262Canonicalize>*
    922       interp_canonicalize_mapping() {
    923     return &interp_canonicalize_mapping_;
    924   }
    925 
    926   ZoneObjectList* frame_element_constant_list() {
    927     return &frame_element_constant_list_;
    928   }
    929 
    930   ZoneObjectList* result_constant_list() {
    931     return &result_constant_list_;
    932   }
    933 
    934   void* PreallocatedStorageNew(size_t size);
    935   void PreallocatedStorageDelete(void* p);
    936   void PreallocatedStorageInit(size_t size);
    937 
    938 #ifdef ENABLE_DEBUGGER_SUPPORT
    939   Debugger* debugger() {
    940     if (!NoBarrier_Load(&debugger_initialized_)) InitializeDebugger();
    941     return debugger_;
    942   }
    943   Debug* debug() {
    944     if (!NoBarrier_Load(&debugger_initialized_)) InitializeDebugger();
    945     return debug_;
    946   }
    947 #endif
    948 
    949 #ifdef ENABLE_LOGGING_AND_PROFILING
    950   ProducerHeapProfile* producer_heap_profile() {
    951     return producer_heap_profile_;
    952   }
    953 #endif
    954 
    955 #ifdef DEBUG
    956   HistogramInfo* heap_histograms() { return heap_histograms_; }
    957 
    958   JSObject::SpillInformation* js_spill_information() {
    959     return &js_spill_information_;
    960   }
    961 
    962   int* code_kind_statistics() { return code_kind_statistics_; }
    963 #endif
    964 
    965 #if defined(V8_TARGET_ARCH_ARM) && !defined(__arm__) || \
    966     defined(V8_TARGET_ARCH_MIPS) && !defined(__mips__)
    967   bool simulator_initialized() { return simulator_initialized_; }
    968   void set_simulator_initialized(bool initialized) {
    969     simulator_initialized_ = initialized;
    970   }
    971 
    972   HashMap* simulator_i_cache() { return simulator_i_cache_; }
    973   void set_simulator_i_cache(HashMap* hash_map) {
    974     simulator_i_cache_ = hash_map;
    975   }
    976 
    977   Redirection* simulator_redirection() {
    978     return simulator_redirection_;
    979   }
    980   void set_simulator_redirection(Redirection* redirection) {
    981     simulator_redirection_ = redirection;
    982   }
    983 #endif
    984 
    985   Factory* factory() { return reinterpret_cast<Factory*>(this); }
    986 
    987   // SerializerDeserializer state.
    988   static const int kPartialSnapshotCacheCapacity = 1400;
    989 
    990   static const int kJSRegexpStaticOffsetsVectorSize = 50;
    991 
    992 #ifdef ENABLE_LOGGING_AND_PROFILING
    993   Address external_callback() {
    994     return thread_local_top_.external_callback_;
    995   }
    996   void set_external_callback(Address callback) {
    997     thread_local_top_.external_callback_ = callback;
    998   }
    999 #endif
   1000 
   1001 #ifdef ENABLE_VMSTATE_TRACKING
   1002   StateTag current_vm_state() {
   1003     return thread_local_top_.current_vm_state_;
   1004   }
   1005 
   1006   void SetCurrentVMState(StateTag state) {
   1007     if (RuntimeProfiler::IsEnabled()) {
   1008       StateTag current_state = thread_local_top_.current_vm_state_;
   1009       if (current_state != JS && state == JS) {
   1010         // Non-JS -> JS transition.
   1011         RuntimeProfiler::IsolateEnteredJS(this);
   1012       } else if (current_state == JS && state != JS) {
   1013         // JS -> non-JS transition.
   1014         ASSERT(RuntimeProfiler::IsSomeIsolateInJS());
   1015         RuntimeProfiler::IsolateExitedJS(this);
   1016       } else {
   1017         // Other types of state transitions are not interesting to the
   1018         // runtime profiler, because they don't affect whether we're
   1019         // in JS or not.
   1020         ASSERT((current_state == JS) == (state == JS));
   1021       }
   1022     }
   1023     thread_local_top_.current_vm_state_ = state;
   1024   }
   1025 #endif
   1026 
   1027   void ResetEagerOptimizingData();
   1028 
   1029  private:
   1030   Isolate();
   1031 
   1032   // The per-process lock should be acquired before the ThreadDataTable is
   1033   // modified.
   1034   class ThreadDataTable {
   1035    public:
   1036     ThreadDataTable();
   1037     ~ThreadDataTable();
   1038 
   1039     PerIsolateThreadData* Lookup(Isolate* isolate, ThreadId thread_id);
   1040     void Insert(PerIsolateThreadData* data);
   1041     void Remove(Isolate* isolate, ThreadId thread_id);
   1042     void Remove(PerIsolateThreadData* data);
   1043 
   1044    private:
   1045     PerIsolateThreadData* list_;
   1046   };
   1047 
   1048   // These items form a stack synchronously with threads Enter'ing and Exit'ing
   1049   // the Isolate. The top of the stack points to a thread which is currently
   1050   // running the Isolate. When the stack is empty, the Isolate is considered
   1051   // not entered by any thread and can be Disposed.
   1052   // If the same thread enters the Isolate more then once, the entry_count_
   1053   // is incremented rather then a new item pushed to the stack.
   1054   class EntryStackItem {
   1055    public:
   1056     EntryStackItem(PerIsolateThreadData* previous_thread_data,
   1057                    Isolate* previous_isolate,
   1058                    EntryStackItem* previous_item)
   1059         : entry_count(1),
   1060           previous_thread_data(previous_thread_data),
   1061           previous_isolate(previous_isolate),
   1062           previous_item(previous_item) { }
   1063 
   1064     int entry_count;
   1065     PerIsolateThreadData* previous_thread_data;
   1066     Isolate* previous_isolate;
   1067     EntryStackItem* previous_item;
   1068 
   1069     DISALLOW_COPY_AND_ASSIGN(EntryStackItem);
   1070   };
   1071 
   1072   // This mutex protects highest_thread_id_, thread_data_table_ and
   1073   // default_isolate_.
   1074   static Mutex* process_wide_mutex_;
   1075 
   1076   static Thread::LocalStorageKey per_isolate_thread_data_key_;
   1077   static Thread::LocalStorageKey isolate_key_;
   1078   static Thread::LocalStorageKey thread_id_key_;
   1079   static Isolate* default_isolate_;
   1080   static ThreadDataTable* thread_data_table_;
   1081 
   1082   void Deinit();
   1083 
   1084   static void SetIsolateThreadLocals(Isolate* isolate,
   1085                                      PerIsolateThreadData* data);
   1086 
   1087   enum State {
   1088     UNINITIALIZED,    // Some components may not have been allocated.
   1089     INITIALIZED       // All components are fully initialized.
   1090   };
   1091 
   1092   State state_;
   1093   EntryStackItem* entry_stack_;
   1094 
   1095   // Allocate and insert PerIsolateThreadData into the ThreadDataTable
   1096   // (regardless of whether such data already exists).
   1097   PerIsolateThreadData* AllocatePerIsolateThreadData(ThreadId thread_id);
   1098 
   1099   // Find the PerThread for this particular (isolate, thread) combination.
   1100   // If one does not yet exist, allocate a new one.
   1101   PerIsolateThreadData* FindOrAllocatePerThreadDataForThisThread();
   1102 
   1103   // PreInits and returns a default isolate. Needed when a new thread tries
   1104   // to create a Locker for the first time (the lock itself is in the isolate).
   1105   static Isolate* GetDefaultIsolateForLocking();
   1106 
   1107   // Initializes the current thread to run this Isolate.
   1108   // Not thread-safe. Multiple threads should not Enter/Exit the same isolate
   1109   // at the same time, this should be prevented using external locking.
   1110   void Enter();
   1111 
   1112   // Exits the current thread. The previosuly entered Isolate is restored
   1113   // for the thread.
   1114   // Not thread-safe. Multiple threads should not Enter/Exit the same isolate
   1115   // at the same time, this should be prevented using external locking.
   1116   void Exit();
   1117 
   1118   void PreallocatedMemoryThreadStart();
   1119   void PreallocatedMemoryThreadStop();
   1120   void InitializeThreadLocal();
   1121 
   1122   void PrintStackTrace(FILE* out, ThreadLocalTop* thread);
   1123   void MarkCompactPrologue(bool is_compacting,
   1124                            ThreadLocalTop* archived_thread_data);
   1125   void MarkCompactEpilogue(bool is_compacting,
   1126                            ThreadLocalTop* archived_thread_data);
   1127 
   1128   void FillCache();
   1129 
   1130   void PropagatePendingExceptionToExternalTryCatch();
   1131 
   1132   void InitializeDebugger();
   1133 
   1134   int stack_trace_nesting_level_;
   1135   StringStream* incomplete_message_;
   1136   // The preallocated memory thread singleton.
   1137   PreallocatedMemoryThread* preallocated_memory_thread_;
   1138   Address isolate_addresses_[k_isolate_address_count + 1];  // NOLINT
   1139   NoAllocationStringAllocator* preallocated_message_space_;
   1140 
   1141   Bootstrapper* bootstrapper_;
   1142   RuntimeProfiler* runtime_profiler_;
   1143   CompilationCache* compilation_cache_;
   1144   Counters* counters_;
   1145   CodeRange* code_range_;
   1146   Mutex* break_access_;
   1147   Atomic32 debugger_initialized_;
   1148   Mutex* debugger_access_;
   1149   Heap heap_;
   1150   Logger* logger_;
   1151   StackGuard stack_guard_;
   1152   StatsTable* stats_table_;
   1153   StubCache* stub_cache_;
   1154   DeoptimizerData* deoptimizer_data_;
   1155   ThreadLocalTop thread_local_top_;
   1156   bool capture_stack_trace_for_uncaught_exceptions_;
   1157   int stack_trace_for_uncaught_exceptions_frame_limit_;
   1158   StackTrace::StackTraceOptions stack_trace_for_uncaught_exceptions_options_;
   1159   TranscendentalCache* transcendental_cache_;
   1160   MemoryAllocator* memory_allocator_;
   1161   KeyedLookupCache* keyed_lookup_cache_;
   1162   ContextSlotCache* context_slot_cache_;
   1163   DescriptorLookupCache* descriptor_lookup_cache_;
   1164   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
   1165   HandleScopeImplementer* handle_scope_implementer_;
   1166   UnicodeCache* unicode_cache_;
   1167   Zone zone_;
   1168   PreallocatedStorage in_use_list_;
   1169   PreallocatedStorage free_list_;
   1170   bool preallocated_storage_preallocated_;
   1171   PcToCodeCache* pc_to_code_cache_;
   1172   StringInputBuffer* write_input_buffer_;
   1173   GlobalHandles* global_handles_;
   1174   ContextSwitcher* context_switcher_;
   1175   ThreadManager* thread_manager_;
   1176   AstSentinels* ast_sentinels_;
   1177   RuntimeState runtime_state_;
   1178   StringInputBuffer liveedit_compare_substrings_buf1_;
   1179   StringInputBuffer liveedit_compare_substrings_buf2_;
   1180   StaticResource<SafeStringInputBuffer> compiler_safe_string_input_buffer_;
   1181   Builtins builtins_;
   1182   StringTracker* string_tracker_;
   1183   unibrow::Mapping<unibrow::Ecma262UnCanonicalize> jsregexp_uncanonicalize_;
   1184   unibrow::Mapping<unibrow::CanonicalizationRange> jsregexp_canonrange_;
   1185   StringInputBuffer objects_string_compare_buffer_a_;
   1186   StringInputBuffer objects_string_compare_buffer_b_;
   1187   StaticResource<StringInputBuffer> objects_string_input_buffer_;
   1188   unibrow::Mapping<unibrow::Ecma262Canonicalize>
   1189       regexp_macro_assembler_canonicalize_;
   1190   RegExpStack* regexp_stack_;
   1191   unibrow::Mapping<unibrow::Ecma262Canonicalize> interp_canonicalize_mapping_;
   1192   ZoneObjectList frame_element_constant_list_;
   1193   ZoneObjectList result_constant_list_;
   1194 
   1195 #if defined(V8_TARGET_ARCH_ARM) && !defined(__arm__) || \
   1196     defined(V8_TARGET_ARCH_MIPS) && !defined(__mips__)
   1197   bool simulator_initialized_;
   1198   HashMap* simulator_i_cache_;
   1199   Redirection* simulator_redirection_;
   1200 #endif
   1201 
   1202 #ifdef DEBUG
   1203   // A static array of histogram info for each type.
   1204   HistogramInfo heap_histograms_[LAST_TYPE + 1];
   1205   JSObject::SpillInformation js_spill_information_;
   1206   int code_kind_statistics_[Code::NUMBER_OF_KINDS];
   1207 #endif
   1208 
   1209 #ifdef ENABLE_DEBUGGER_SUPPORT
   1210   Debugger* debugger_;
   1211   Debug* debug_;
   1212 #endif
   1213 
   1214 #ifdef ENABLE_LOGGING_AND_PROFILING
   1215   ProducerHeapProfile* producer_heap_profile_;
   1216 #endif
   1217 
   1218 #define GLOBAL_BACKING_STORE(type, name, initialvalue)                         \
   1219   type name##_;
   1220   ISOLATE_INIT_LIST(GLOBAL_BACKING_STORE)
   1221 #undef GLOBAL_BACKING_STORE
   1222 
   1223 #define GLOBAL_ARRAY_BACKING_STORE(type, name, length)                         \
   1224   type name##_[length];
   1225   ISOLATE_INIT_ARRAY_LIST(GLOBAL_ARRAY_BACKING_STORE)
   1226 #undef GLOBAL_ARRAY_BACKING_STORE
   1227 
   1228 #ifdef DEBUG
   1229   // This class is huge and has a number of fields controlled by
   1230   // preprocessor defines. Make sure the offsets of these fields agree
   1231   // between compilation units.
   1232 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                              \
   1233   static const intptr_t name##_debug_offset_;
   1234   ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
   1235   ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
   1236 #undef ISOLATE_FIELD_OFFSET
   1237 #endif
   1238 
   1239   friend class ExecutionAccess;
   1240   friend class IsolateInitializer;
   1241   friend class ThreadId;
   1242   friend class TestMemoryAllocatorScope;
   1243   friend class v8::Isolate;
   1244   friend class v8::Locker;
   1245 
   1246   DISALLOW_COPY_AND_ASSIGN(Isolate);
   1247 };
   1248 
   1249 
   1250 // If the GCC version is 4.1.x or 4.2.x an additional field is added to the
   1251 // class as a work around for a bug in the generated code found with these
   1252 // versions of GCC. See V8 issue 122 for details.
   1253 class SaveContext BASE_EMBEDDED {
   1254  public:
   1255   explicit SaveContext(Isolate* isolate) : prev_(isolate->save_context()) {
   1256     if (isolate->context() != NULL) {
   1257       context_ = Handle<Context>(isolate->context());
   1258 #if __GNUC_VERSION__ >= 40100 && __GNUC_VERSION__ < 40300
   1259       dummy_ = Handle<Context>(isolate->context());
   1260 #endif
   1261     }
   1262     isolate->set_save_context(this);
   1263 
   1264     // If there is no JS frame under the current C frame, use the value 0.
   1265     JavaScriptFrameIterator it(isolate);
   1266     js_sp_ = it.done() ? 0 : it.frame()->sp();
   1267   }
   1268 
   1269   ~SaveContext() {
   1270     if (context_.is_null()) {
   1271       Isolate* isolate = Isolate::Current();
   1272       isolate->set_context(NULL);
   1273       isolate->set_save_context(prev_);
   1274     } else {
   1275       Isolate* isolate = context_->GetIsolate();
   1276       isolate->set_context(*context_);
   1277       isolate->set_save_context(prev_);
   1278     }
   1279   }
   1280 
   1281   Handle<Context> context() { return context_; }
   1282   SaveContext* prev() { return prev_; }
   1283 
   1284   // Returns true if this save context is below a given JavaScript frame.
   1285   bool below(JavaScriptFrame* frame) {
   1286     return (js_sp_ == 0) || (frame->sp() < js_sp_);
   1287   }
   1288 
   1289  private:
   1290   Handle<Context> context_;
   1291 #if __GNUC_VERSION__ >= 40100 && __GNUC_VERSION__ < 40300
   1292   Handle<Context> dummy_;
   1293 #endif
   1294   SaveContext* prev_;
   1295   Address js_sp_;  // The top JS frame's sp when saving context.
   1296 };
   1297 
   1298 
   1299 class AssertNoContextChange BASE_EMBEDDED {
   1300 #ifdef DEBUG
   1301  public:
   1302   AssertNoContextChange() :
   1303       scope_(Isolate::Current()),
   1304       context_(Isolate::Current()->context(), Isolate::Current()) {
   1305   }
   1306 
   1307   ~AssertNoContextChange() {
   1308     ASSERT(Isolate::Current()->context() == *context_);
   1309   }
   1310 
   1311  private:
   1312   HandleScope scope_;
   1313   Handle<Context> context_;
   1314 #else
   1315  public:
   1316   AssertNoContextChange() { }
   1317 #endif
   1318 };
   1319 
   1320 
   1321 class ExecutionAccess BASE_EMBEDDED {
   1322  public:
   1323   explicit ExecutionAccess(Isolate* isolate) : isolate_(isolate) {
   1324     Lock(isolate);
   1325   }
   1326   ~ExecutionAccess() { Unlock(isolate_); }
   1327 
   1328   static void Lock(Isolate* isolate) { isolate->break_access_->Lock(); }
   1329   static void Unlock(Isolate* isolate) { isolate->break_access_->Unlock(); }
   1330 
   1331   static bool TryLock(Isolate* isolate) {
   1332     return isolate->break_access_->TryLock();
   1333   }
   1334 
   1335  private:
   1336   Isolate* isolate_;
   1337 };
   1338 
   1339 
   1340 // Support for checking for stack-overflows in C++ code.
   1341 class StackLimitCheck BASE_EMBEDDED {
   1342  public:
   1343   explicit StackLimitCheck(Isolate* isolate) : isolate_(isolate) { }
   1344 
   1345   bool HasOverflowed() const {
   1346     StackGuard* stack_guard = isolate_->stack_guard();
   1347     // Stack has overflowed in C++ code only if stack pointer exceeds the C++
   1348     // stack guard and the limits are not set to interrupt values.
   1349     // TODO(214): Stack overflows are ignored if a interrupt is pending. This
   1350     // code should probably always use the initial C++ limit.
   1351     return (reinterpret_cast<uintptr_t>(this) < stack_guard->climit()) &&
   1352            stack_guard->IsStackOverflow();
   1353   }
   1354  private:
   1355   Isolate* isolate_;
   1356 };
   1357 
   1358 
   1359 // Support for temporarily postponing interrupts. When the outermost
   1360 // postpone scope is left the interrupts will be re-enabled and any
   1361 // interrupts that occurred while in the scope will be taken into
   1362 // account.
   1363 class PostponeInterruptsScope BASE_EMBEDDED {
   1364  public:
   1365   explicit PostponeInterruptsScope(Isolate* isolate)
   1366       : stack_guard_(isolate->stack_guard()) {
   1367     stack_guard_->thread_local_.postpone_interrupts_nesting_++;
   1368     stack_guard_->DisableInterrupts();
   1369   }
   1370 
   1371   ~PostponeInterruptsScope() {
   1372     if (--stack_guard_->thread_local_.postpone_interrupts_nesting_ == 0) {
   1373       stack_guard_->EnableInterrupts();
   1374     }
   1375   }
   1376  private:
   1377   StackGuard* stack_guard_;
   1378 };
   1379 
   1380 
   1381 // Temporary macros for accessing current isolate and its subobjects.
   1382 // They provide better readability, especially when used a lot in the code.
   1383 #define HEAP (v8::internal::Isolate::Current()->heap())
   1384 #define FACTORY (v8::internal::Isolate::Current()->factory())
   1385 #define ISOLATE (v8::internal::Isolate::Current())
   1386 #define ZONE (v8::internal::Isolate::Current()->zone())
   1387 #define LOGGER (v8::internal::Isolate::Current()->logger())
   1388 
   1389 
   1390 // Tells whether the global context is marked with out of memory.
   1391 inline bool Context::has_out_of_memory() {
   1392   return global_context()->out_of_memory()->IsTrue();
   1393 }
   1394 
   1395 
   1396 // Mark the global context with out of memory.
   1397 inline void Context::mark_out_of_memory() {
   1398   global_context()->set_out_of_memory(HEAP->true_value());
   1399 }
   1400 
   1401 
   1402 // Temporary macro to be used to flag definitions that are indeed static
   1403 // and not per-isolate. (It would be great to be able to grep for [static]!)
   1404 #define RLYSTC static
   1405 
   1406 
   1407 // Temporary macro to be used to flag classes that should be static.
   1408 #define STATIC_CLASS class
   1409 
   1410 
   1411 // Temporary macro to be used to flag classes that are completely converted
   1412 // to be isolate-friendly. Their mix of static/nonstatic methods/fields is
   1413 // correct.
   1414 #define ISOLATED_CLASS class
   1415 
   1416 } }  // namespace v8::internal
   1417 
   1418 // TODO(isolates): Get rid of these -inl.h includes and place them only where
   1419 //                 they're needed.
   1420 #include "allocation-inl.h"
   1421 #include "zone-inl.h"
   1422 #include "frames-inl.h"
   1423 
   1424 #endif  // V8_ISOLATE_H_
   1425