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
33namespace v8 {
34namespace internal {
35
36
37// Flag used to set the interrupt causes.
38enum 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
49class Isolate;
50
51
52class 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
165class 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.
171class 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);
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.
211  uintptr_t climit() {
212    return thread_local_.climit_;
213  }
214  uintptr_t real_climit() {
215    return thread_local_.real_climit_;
216  }
217  uintptr_t jslimit() {
218    return thread_local_.jslimit_;
219  }
220  uintptr_t real_jslimit() {
221    return thread_local_.real_jslimit_;
222  }
223  Address address_of_jslimit() {
224    return reinterpret_cast<Address>(&thread_local_.jslimit_);
225  }
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.
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.
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:
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