• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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_EXECUTION_H_
29 #define V8_EXECUTION_H_
30 
31 #include "allocation.h"
32 
33 namespace v8 {
34 namespace internal {
35 
36 
37 // Flag used to set the interrupt causes.
38 enum InterruptFlag {
39   INTERRUPT = 1 << 0,
40   DEBUGBREAK = 1 << 1,
41   DEBUGCOMMAND = 1 << 2,
42   PREEMPT = 1 << 3,
43   TERMINATE = 1 << 4,
44   RUNTIME_PROFILER_TICK = 1 << 5,
45   GC_REQUEST = 1 << 6
46 };
47 
48 
49 class Isolate;
50 
51 
52 class Execution : public AllStatic {
53  public:
54   // Call a function, the caller supplies a receiver and an array
55   // of arguments. Arguments are Object* type. After function returns,
56   // pointers in 'args' might be invalid.
57   //
58   // *pending_exception tells whether the invoke resulted in
59   // a pending exception.
60   //
61   // When convert_receiver is set, and the receiver is not an object,
62   // and the function called is not in strict mode, receiver is converted to
63   // an object.
64   //
65   static Handle<Object> Call(Handle<Object> callable,
66                              Handle<Object> receiver,
67                              int argc,
68                              Handle<Object> argv[],
69                              bool* pending_exception,
70                              bool convert_receiver = false);
71 
72   // Construct object from function, the caller supplies an array of
73   // arguments. Arguments are Object* type. After function returns,
74   // pointers in 'args' might be invalid.
75   //
76   // *pending_exception tells whether the invoke resulted in
77   // a pending exception.
78   //
79   static Handle<Object> New(Handle<JSFunction> func,
80                             int argc,
81                             Handle<Object> argv[],
82                             bool* pending_exception);
83 
84   // Call a function, just like Call(), but make sure to silently catch
85   // any thrown exceptions. The return value is either the result of
86   // calling the function (if caught exception is false) or the exception
87   // that occurred (if caught exception is true).
88   static Handle<Object> TryCall(Handle<JSFunction> func,
89                                 Handle<Object> receiver,
90                                 int argc,
91                                 Handle<Object> argv[],
92                                 bool* caught_exception);
93 
94   // ECMA-262 9.2
95   static Handle<Object> ToBoolean(Handle<Object> obj);
96 
97   // ECMA-262 9.3
98   static Handle<Object> ToNumber(Handle<Object> obj, bool* exc);
99 
100   // ECMA-262 9.4
101   static Handle<Object> ToInteger(Handle<Object> obj, bool* exc);
102 
103   // ECMA-262 9.5
104   static Handle<Object> ToInt32(Handle<Object> obj, bool* exc);
105 
106   // ECMA-262 9.6
107   static Handle<Object> ToUint32(Handle<Object> obj, bool* exc);
108 
109   // ECMA-262 9.8
110   static Handle<Object> ToString(Handle<Object> obj, bool* exc);
111 
112   // ECMA-262 9.8
113   static Handle<Object> ToDetailString(Handle<Object> obj, bool* exc);
114 
115   // ECMA-262 9.9
116   static Handle<Object> ToObject(Handle<Object> obj, bool* exc);
117 
118   // Create a new date object from 'time'.
119   static Handle<Object> NewDate(double time, bool* exc);
120 
121   // Create a new regular expression object from 'pattern' and 'flags'.
122   static Handle<JSRegExp> NewJSRegExp(Handle<String> pattern,
123                                       Handle<String> flags,
124                                       bool* exc);
125 
126   // Used to implement [] notation on strings (calls JS code)
127   static Handle<Object> CharAt(Handle<String> str, uint32_t index);
128 
129   static Handle<Object> GetFunctionFor();
130   static Handle<JSFunction> InstantiateFunction(
131       Handle<FunctionTemplateInfo> data, bool* exc);
132   static Handle<JSObject> InstantiateObject(Handle<ObjectTemplateInfo> data,
133                                             bool* exc);
134   static void ConfigureInstance(Handle<Object> instance,
135                                 Handle<Object> data,
136                                 bool* exc);
137   static Handle<String> GetStackTraceLine(Handle<Object> recv,
138                                           Handle<JSFunction> fun,
139                                           Handle<Object> pos,
140                                           Handle<Object> is_global);
141 #ifdef ENABLE_DEBUGGER_SUPPORT
142   static Object* DebugBreakHelper();
143   static void ProcessDebugMessages(bool debug_command_only);
144 #endif
145 
146   // If the stack guard is triggered, but it is not an actual
147   // stack overflow, then handle the interruption accordingly.
148   MUST_USE_RESULT static MaybeObject* HandleStackGuardInterrupt(
149       Isolate* isolate);
150 
151   // Get a function delegate (or undefined) for the given non-function
152   // object. Used for support calling objects as functions.
153   static Handle<Object> GetFunctionDelegate(Handle<Object> object);
154   static Handle<Object> TryGetFunctionDelegate(Handle<Object> object,
155                                                bool* has_pending_exception);
156 
157   // Get a function delegate (or undefined) for the given non-function
158   // object. Used for support calling objects as constructors.
159   static Handle<Object> GetConstructorDelegate(Handle<Object> object);
160   static Handle<Object> TryGetConstructorDelegate(Handle<Object> object,
161                                                   bool* has_pending_exception);
162 };
163 
164 
165 class ExecutionAccess;
166 
167 
168 // StackGuard contains the handling of the limits that are used to limit the
169 // number of nested invocations of JavaScript and the stack size used in each
170 // invocation.
171 class StackGuard {
172  public:
173   // Pass the address beyond which the stack should not grow.  The stack
174   // is assumed to grow downwards.
175   void SetStackLimit(uintptr_t limit);
176 
177   // Threading support.
178   char* ArchiveStackGuard(char* to);
179   char* RestoreStackGuard(char* from);
ArchiveSpacePerThread()180   static int ArchiveSpacePerThread() { return sizeof(ThreadLocal); }
181   void FreeThreadResources();
182   // Sets up the default stack guard for this thread if it has not
183   // already been set up.
184   void InitThread(const ExecutionAccess& lock);
185   // Clears the stack guard for this thread so it does not look as if
186   // it has been set up.
187   void ClearThread(const ExecutionAccess& lock);
188 
189   bool IsStackOverflow();
190   bool IsPreempted();
191   void Preempt();
192   bool IsInterrupted();
193   void Interrupt();
194   bool IsTerminateExecution();
195   void TerminateExecution();
196   bool IsRuntimeProfilerTick();
197   void RequestRuntimeProfilerTick();
198 #ifdef ENABLE_DEBUGGER_SUPPORT
199   bool IsDebugBreak();
200   void DebugBreak();
201   bool IsDebugCommand();
202   void DebugCommand();
203 #endif
204   bool IsGCRequest();
205   void RequestGC();
206   void Continue(InterruptFlag after_what);
207 
208   // This provides an asynchronous read of the stack limits for the current
209   // thread.  There are no locks protecting this, but it is assumed that you
210   // have the global V8 lock if you are using multiple V8 threads.
climit()211   uintptr_t climit() {
212     return thread_local_.climit_;
213   }
real_climit()214   uintptr_t real_climit() {
215     return thread_local_.real_climit_;
216   }
jslimit()217   uintptr_t jslimit() {
218     return thread_local_.jslimit_;
219   }
real_jslimit()220   uintptr_t real_jslimit() {
221     return thread_local_.real_jslimit_;
222   }
address_of_jslimit()223   Address address_of_jslimit() {
224     return reinterpret_cast<Address>(&thread_local_.jslimit_);
225   }
address_of_real_jslimit()226   Address address_of_real_jslimit() {
227     return reinterpret_cast<Address>(&thread_local_.real_jslimit_);
228   }
229   bool ShouldPostponeInterrupts();
230 
231  private:
232   StackGuard();
233 
234   // You should hold the ExecutionAccess lock when calling this method.
has_pending_interrupts(const ExecutionAccess & lock)235   bool has_pending_interrupts(const ExecutionAccess& lock) {
236     // Sanity check: We shouldn't be asking about pending interrupts
237     // unless we're not postponing them anymore.
238     ASSERT(!should_postpone_interrupts(lock));
239     return thread_local_.interrupt_flags_ != 0;
240   }
241 
242   // You should hold the ExecutionAccess lock when calling this method.
should_postpone_interrupts(const ExecutionAccess & lock)243   bool should_postpone_interrupts(const ExecutionAccess& lock) {
244     return thread_local_.postpone_interrupts_nesting_ > 0;
245   }
246 
247   // You should hold the ExecutionAccess lock when calling this method.
248   inline void set_interrupt_limits(const ExecutionAccess& lock);
249 
250   // Reset limits to actual values. For example after handling interrupt.
251   // You should hold the ExecutionAccess lock when calling this method.
252   inline void reset_limits(const ExecutionAccess& lock);
253 
254   // Enable or disable interrupts.
255   void EnableInterrupts();
256   void DisableInterrupts();
257 
258 #ifdef V8_TARGET_ARCH_X64
259   static const uintptr_t kInterruptLimit = V8_UINT64_C(0xfffffffffffffffe);
260   static const uintptr_t kIllegalLimit = V8_UINT64_C(0xfffffffffffffff8);
261 #else
262   static const uintptr_t kInterruptLimit = 0xfffffffe;
263   static const uintptr_t kIllegalLimit = 0xfffffff8;
264 #endif
265 
266   class ThreadLocal {
267    public:
ThreadLocal()268     ThreadLocal() { Clear(); }
269     // You should hold the ExecutionAccess lock when you call Initialize or
270     // Clear.
271     void Clear();
272 
273     // Returns true if the heap's stack limits should be set, false if not.
274     bool Initialize(Isolate* isolate);
275 
276     // The stack limit is split into a JavaScript and a C++ stack limit. These
277     // two are the same except when running on a simulator where the C++ and
278     // JavaScript stacks are separate. Each of the two stack limits have two
279     // values. The one eith the real_ prefix is the actual stack limit
280     // set for the VM. The one without the real_ prefix has the same value as
281     // the actual stack limit except when there is an interruption (e.g. debug
282     // break or preemption) in which case it is lowered to make stack checks
283     // fail. Both the generated code and the runtime system check against the
284     // one without the real_ prefix.
285     uintptr_t real_jslimit_;  // Actual JavaScript stack limit set for the VM.
286     uintptr_t jslimit_;
287     uintptr_t real_climit_;  // Actual C++ stack limit set for the VM.
288     uintptr_t climit_;
289 
290     int nesting_;
291     int postpone_interrupts_nesting_;
292     int interrupt_flags_;
293   };
294 
295   // TODO(isolates): Technically this could be calculated directly from a
296   //                 pointer to StackGuard.
297   Isolate* isolate_;
298   ThreadLocal thread_local_;
299 
300   friend class Isolate;
301   friend class StackLimitCheck;
302   friend class PostponeInterruptsScope;
303 
304   DISALLOW_COPY_AND_ASSIGN(StackGuard);
305 };
306 
307 
308 } }  // namespace v8::internal
309 
310 #endif  // V8_EXECUTION_H_
311