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1 : // Copyright 2014 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #ifndef V8_EXECUTION_H_
6 : #define V8_EXECUTION_H_
7 :
8 : #include "src/base/atomicops.h"
9 : #include "src/globals.h"
10 :
11 : namespace v8 {
12 : namespace internal {
13 :
14 : class MicrotaskQueue;
15 :
16 : template <typename T>
17 : class Handle;
18 :
19 : class Execution final : public AllStatic {
20 : public:
21 : // Whether to report pending messages, or keep them pending on the isolate.
22 : enum class MessageHandling { kReport, kKeepPending };
23 : enum class Target { kCallable, kRunMicrotasks };
24 :
25 : // Call a function, the caller supplies a receiver and an array
26 : // of arguments.
27 : //
28 : // When the function called is not in strict mode, receiver is
29 : // converted to an object.
30 : //
31 : V8_EXPORT_PRIVATE V8_WARN_UNUSED_RESULT static MaybeHandle<Object> Call(
32 : Isolate* isolate, Handle<Object> callable, Handle<Object> receiver,
33 : int argc, Handle<Object> argv[]);
34 :
35 : // Construct object from function, the caller supplies an array of
36 : // arguments.
37 : V8_WARN_UNUSED_RESULT static MaybeHandle<Object> New(
38 : Isolate* isolate, Handle<Object> constructor, int argc,
39 : Handle<Object> argv[]);
40 : V8_WARN_UNUSED_RESULT static MaybeHandle<Object> New(
41 : Isolate* isolate, Handle<Object> constructor, Handle<Object> new_target,
42 : int argc, Handle<Object> argv[]);
43 :
44 : // Call a function, just like Call(), but handle don't report exceptions
45 : // externally.
46 : // The return value is either the result of calling the function (if no
47 : // exception occurred), or an empty handle.
48 : // If message_handling is MessageHandling::kReport, exceptions (except for
49 : // termination exceptions) will be stored in exception_out (if not a
50 : // nullptr).
51 : static MaybeHandle<Object> TryCall(Isolate* isolate, Handle<Object> callable,
52 : Handle<Object> receiver, int argc,
53 : Handle<Object> argv[],
54 : MessageHandling message_handling,
55 : MaybeHandle<Object>* exception_out);
56 : // Convenience method for performing RunMicrotasks
57 : static MaybeHandle<Object> TryRunMicrotasks(
58 : Isolate* isolate, MicrotaskQueue* microtask_queue,
59 : MaybeHandle<Object>* exception_out);
60 : };
61 :
62 :
63 : class ExecutionAccess;
64 : class InterruptsScope;
65 :
66 : // StackGuard contains the handling of the limits that are used to limit the
67 : // number of nested invocations of JavaScript and the stack size used in each
68 : // invocation.
69 : class V8_EXPORT_PRIVATE StackGuard final {
70 : public:
71 62882 : explicit StackGuard(Isolate* isolate) : isolate_(isolate) {}
72 :
73 : // Pass the address beyond which the stack should not grow. The stack
74 : // is assumed to grow downwards.
75 : void SetStackLimit(uintptr_t limit);
76 :
77 : // The simulator uses a separate JS stack. Limits on the JS stack might have
78 : // to be adjusted in order to reflect overflows of the C stack, because we
79 : // cannot rely on the interleaving of frames on the simulator.
80 : void AdjustStackLimitForSimulator();
81 :
82 : // Threading support.
83 : char* ArchiveStackGuard(char* to);
84 : char* RestoreStackGuard(char* from);
85 : static int ArchiveSpacePerThread() { return sizeof(ThreadLocal); }
86 : void FreeThreadResources();
87 : // Sets up the default stack guard for this thread if it has not
88 : // already been set up.
89 : void InitThread(const ExecutionAccess& lock);
90 : // Clears the stack guard for this thread so it does not look as if
91 : // it has been set up.
92 : void ClearThread(const ExecutionAccess& lock);
93 :
94 : #define INTERRUPT_LIST(V) \
95 : V(TERMINATE_EXECUTION, TerminateExecution, 0) \
96 : V(GC_REQUEST, GC, 1) \
97 : V(INSTALL_CODE, InstallCode, 2) \
98 : V(API_INTERRUPT, ApiInterrupt, 3) \
99 : V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 4)
100 :
101 : #define V(NAME, Name, id) \
102 : inline bool Check##Name() { return CheckInterrupt(NAME); } \
103 : inline bool CheckAndClear##Name() { return CheckAndClearInterrupt(NAME); } \
104 : inline void Request##Name() { RequestInterrupt(NAME); } \
105 : inline void Clear##Name() { ClearInterrupt(NAME); }
106 1339649 : INTERRUPT_LIST(V)
107 : #undef V
108 :
109 : // Flag used to set the interrupt causes.
110 : enum InterruptFlag {
111 : #define V(NAME, Name, id) NAME = (1 << id),
112 : INTERRUPT_LIST(V)
113 : #undef V
114 : #define V(NAME, Name, id) NAME |
115 : ALL_INTERRUPTS = INTERRUPT_LIST(V) 0
116 : #undef V
117 : };
118 :
119 : uintptr_t climit() { return thread_local_.climit(); }
120 : uintptr_t jslimit() { return thread_local_.jslimit(); }
121 : // This provides an asynchronous read of the stack limits for the current
122 : // thread. There are no locks protecting this, but it is assumed that you
123 : // have the global V8 lock if you are using multiple V8 threads.
124 : uintptr_t real_climit() {
125 : return thread_local_.real_climit_;
126 : }
127 : uintptr_t real_jslimit() {
128 : return thread_local_.real_jslimit_;
129 : }
130 : Address address_of_jslimit() {
131 2972855 : return reinterpret_cast<Address>(&thread_local_.jslimit_);
132 : }
133 : Address address_of_real_jslimit() {
134 1581675 : return reinterpret_cast<Address>(&thread_local_.real_jslimit_);
135 : }
136 :
137 : // If the stack guard is triggered, but it is not an actual
138 : // stack overflow, then handle the interruption accordingly.
139 : Object HandleInterrupts();
140 :
141 : private:
142 : bool CheckInterrupt(InterruptFlag flag);
143 : void RequestInterrupt(InterruptFlag flag);
144 : void ClearInterrupt(InterruptFlag flag);
145 : bool CheckAndClearInterrupt(InterruptFlag flag);
146 :
147 : // You should hold the ExecutionAccess lock when calling this method.
148 : bool has_pending_interrupts(const ExecutionAccess& lock) {
149 : return thread_local_.interrupt_flags_ != 0;
150 : }
151 :
152 : // You should hold the ExecutionAccess lock when calling this method.
153 : inline void set_interrupt_limits(const ExecutionAccess& lock);
154 :
155 : // Reset limits to actual values. For example after handling interrupt.
156 : // You should hold the ExecutionAccess lock when calling this method.
157 : inline void reset_limits(const ExecutionAccess& lock);
158 :
159 : // Enable or disable interrupts.
160 : void EnableInterrupts();
161 : void DisableInterrupts();
162 :
163 : #if V8_TARGET_ARCH_64_BIT
164 : static const uintptr_t kInterruptLimit = uintptr_t{0xfffffffffffffffe};
165 : static const uintptr_t kIllegalLimit = uintptr_t{0xfffffffffffffff8};
166 : #else
167 : static const uintptr_t kInterruptLimit = 0xfffffffe;
168 : static const uintptr_t kIllegalLimit = 0xfffffff8;
169 : #endif
170 :
171 : void PushInterruptsScope(InterruptsScope* scope);
172 : void PopInterruptsScope();
173 :
174 : class ThreadLocal final {
175 : public:
176 87138 : ThreadLocal() { Clear(); }
177 : // You should hold the ExecutionAccess lock when you call Initialize or
178 : // Clear.
179 : void Clear();
180 :
181 : // Returns true if the heap's stack limits should be set, false if not.
182 : bool Initialize(Isolate* isolate);
183 :
184 : // The stack limit is split into a JavaScript and a C++ stack limit. These
185 : // two are the same except when running on a simulator where the C++ and
186 : // JavaScript stacks are separate. Each of the two stack limits have two
187 : // values. The one eith the real_ prefix is the actual stack limit
188 : // set for the VM. The one without the real_ prefix has the same value as
189 : // the actual stack limit except when there is an interruption (e.g. debug
190 : // break or preemption) in which case it is lowered to make stack checks
191 : // fail. Both the generated code and the runtime system check against the
192 : // one without the real_ prefix.
193 : uintptr_t real_jslimit_; // Actual JavaScript stack limit set for the VM.
194 : uintptr_t real_climit_; // Actual C++ stack limit set for the VM.
195 :
196 : // jslimit_ and climit_ can be read without any lock.
197 : // Writing requires the ExecutionAccess lock.
198 : base::AtomicWord jslimit_;
199 : base::AtomicWord climit_;
200 :
201 : uintptr_t jslimit() {
202 7301862 : return bit_cast<uintptr_t>(base::Relaxed_Load(&jslimit_));
203 : }
204 : void set_jslimit(uintptr_t limit) {
205 : return base::Relaxed_Store(&jslimit_,
206 7212623 : static_cast<base::AtomicWord>(limit));
207 : }
208 : uintptr_t climit() {
209 52116218 : return bit_cast<uintptr_t>(base::Relaxed_Load(&climit_));
210 : }
211 : void set_climit(uintptr_t limit) {
212 : return base::Relaxed_Store(&climit_,
213 7212623 : static_cast<base::AtomicWord>(limit));
214 : }
215 :
216 : InterruptsScope* interrupt_scopes_;
217 : int interrupt_flags_;
218 : };
219 :
220 : // TODO(isolates): Technically this could be calculated directly from a
221 : // pointer to StackGuard.
222 : Isolate* isolate_;
223 : ThreadLocal thread_local_;
224 :
225 : friend class Isolate;
226 : friend class StackLimitCheck;
227 : friend class InterruptsScope;
228 :
229 : DISALLOW_COPY_AND_ASSIGN(StackGuard);
230 : };
231 :
232 : } // namespace internal
233 : } // namespace v8
234 :
235 : #endif // V8_EXECUTION_H_
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