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/allocation.h" 9 #include "src/base/atomicops.h" 10 #include "src/handles.h" 11 #include "src/utils.h" 12 13 namespace v8 { 14 namespace internal { 15 16 class Execution final : public AllStatic { 17 public: 18 // Call a function, the caller supplies a receiver and an array 19 // of arguments. 20 // 21 // When the function called is not in strict mode, receiver is 22 // converted to an object. 23 // 24 MUST_USE_RESULT static MaybeHandle<Object> Call(Isolate* isolate, 25 Handle<Object> callable, 26 Handle<Object> receiver, 27 int argc, 28 Handle<Object> argv[]); 29 30 // Construct object from function, the caller supplies an array of 31 // arguments. 32 MUST_USE_RESULT static MaybeHandle<Object> New(Handle<JSFunction> constructor, 33 int argc, 34 Handle<Object> argv[]); 35 MUST_USE_RESULT static MaybeHandle<Object> New(Isolate* isolate, 36 Handle<Object> constructor, 37 Handle<Object> new_target, 38 int argc, 39 Handle<Object> argv[]); 40 41 // Call a function, just like Call(), but make sure to silently catch 42 // any thrown exceptions. The return value is either the result of 43 // calling the function (if caught exception is false) or the exception 44 // that occurred (if caught exception is true). 45 // In the exception case, exception_out holds the caught exceptions, unless 46 // it is a termination exception. 47 static MaybeHandle<Object> TryCall(Isolate* isolate, Handle<Object> callable, 48 Handle<Object> receiver, int argc, 49 Handle<Object> argv[], 50 MaybeHandle<Object>* exception_out = NULL); 51 52 // ECMA-262 9.9 53 MUST_USE_RESULT static MaybeHandle<JSReceiver> ToObject(Isolate* isolate, 54 Handle<Object> obj); 55 56 static Handle<String> GetStackTraceLine(Handle<Object> recv, 57 Handle<JSFunction> fun, 58 Handle<Object> pos, 59 Handle<Object> is_global); 60 }; 61 62 63 class ExecutionAccess; 64 class PostponeInterruptsScope; 65 66 67 // StackGuard contains the handling of the limits that are used to limit the 68 // number of nested invocations of JavaScript and the stack size used in each 69 // invocation. 70 class StackGuard final { 71 public: 72 // Pass the address beyond which the stack should not grow. The stack 73 // is assumed to grow downwards. 74 void SetStackLimit(uintptr_t limit); 75 76 // The simulator uses a separate JS stack. Limits on the JS stack might have 77 // to be adjusted in order to reflect overflows of the C stack, because we 78 // cannot rely on the interleaving of frames on the simulator. 79 void AdjustStackLimitForSimulator(); 80 81 // Threading support. 82 char* ArchiveStackGuard(char* to); 83 char* RestoreStackGuard(char* from); 84 static int ArchiveSpacePerThread() { return sizeof(ThreadLocal); } 85 void FreeThreadResources(); 86 // Sets up the default stack guard for this thread if it has not 87 // already been set up. 88 void InitThread(const ExecutionAccess& lock); 89 // Clears the stack guard for this thread so it does not look as if 90 // it has been set up. 91 void ClearThread(const ExecutionAccess& lock); 92 93 #define INTERRUPT_LIST(V) \ 94 V(DEBUGBREAK, DebugBreak, 0) \ 95 V(DEBUGCOMMAND, DebugCommand, 1) \ 96 V(TERMINATE_EXECUTION, TerminateExecution, 2) \ 97 V(GC_REQUEST, GC, 3) \ 98 V(INSTALL_CODE, InstallCode, 4) \ 99 V(API_INTERRUPT, ApiInterrupt, 5) \ 100 V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 6) 101 102 #define V(NAME, Name, id) \ 103 inline bool Check##Name() { return CheckInterrupt(NAME); } \ 104 inline void Request##Name() { RequestInterrupt(NAME); } \ 105 inline void Clear##Name() { ClearInterrupt(NAME); } 106 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 return reinterpret_cast<Address>(&thread_local_.jslimit_); 132 } 133 Address address_of_real_jslimit() { 134 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 void HandleGCInterrupt(); 141 142 private: 143 StackGuard(); 144 145 bool CheckInterrupt(InterruptFlag flag); 146 void RequestInterrupt(InterruptFlag flag); 147 void ClearInterrupt(InterruptFlag flag); 148 bool CheckAndClearInterrupt(InterruptFlag flag); 149 150 // You should hold the ExecutionAccess lock when calling this method. 151 bool has_pending_interrupts(const ExecutionAccess& lock) { 152 return thread_local_.interrupt_flags_ != 0; 153 } 154 155 // You should hold the ExecutionAccess lock when calling this method. 156 inline void set_interrupt_limits(const ExecutionAccess& lock); 157 158 // Reset limits to actual values. For example after handling interrupt. 159 // You should hold the ExecutionAccess lock when calling this method. 160 inline void reset_limits(const ExecutionAccess& lock); 161 162 // Enable or disable interrupts. 163 void EnableInterrupts(); 164 void DisableInterrupts(); 165 166 #if V8_TARGET_ARCH_64_BIT 167 static const uintptr_t kInterruptLimit = V8_UINT64_C(0xfffffffffffffffe); 168 static const uintptr_t kIllegalLimit = V8_UINT64_C(0xfffffffffffffff8); 169 #else 170 static const uintptr_t kInterruptLimit = 0xfffffffe; 171 static const uintptr_t kIllegalLimit = 0xfffffff8; 172 #endif 173 174 void PushPostponeInterruptsScope(PostponeInterruptsScope* scope); 175 void PopPostponeInterruptsScope(); 176 177 class ThreadLocal final { 178 public: 179 ThreadLocal() { Clear(); } 180 // You should hold the ExecutionAccess lock when you call Initialize or 181 // Clear. 182 void Clear(); 183 184 // Returns true if the heap's stack limits should be set, false if not. 185 bool Initialize(Isolate* isolate); 186 187 // The stack limit is split into a JavaScript and a C++ stack limit. These 188 // two are the same except when running on a simulator where the C++ and 189 // JavaScript stacks are separate. Each of the two stack limits have two 190 // values. The one eith the real_ prefix is the actual stack limit 191 // set for the VM. The one without the real_ prefix has the same value as 192 // the actual stack limit except when there is an interruption (e.g. debug 193 // break or preemption) in which case it is lowered to make stack checks 194 // fail. Both the generated code and the runtime system check against the 195 // one without the real_ prefix. 196 uintptr_t real_jslimit_; // Actual JavaScript stack limit set for the VM. 197 uintptr_t real_climit_; // Actual C++ stack limit set for the VM. 198 199 // jslimit_ and climit_ can be read without any lock. 200 // Writing requires the ExecutionAccess lock. 201 base::AtomicWord jslimit_; 202 base::AtomicWord climit_; 203 204 uintptr_t jslimit() { 205 return bit_cast<uintptr_t>(base::NoBarrier_Load(&jslimit_)); 206 } 207 void set_jslimit(uintptr_t limit) { 208 return base::NoBarrier_Store(&jslimit_, 209 static_cast<base::AtomicWord>(limit)); 210 } 211 uintptr_t climit() { 212 return bit_cast<uintptr_t>(base::NoBarrier_Load(&climit_)); 213 } 214 void set_climit(uintptr_t limit) { 215 return base::NoBarrier_Store(&climit_, 216 static_cast<base::AtomicWord>(limit)); 217 } 218 219 PostponeInterruptsScope* postpone_interrupts_; 220 int interrupt_flags_; 221 }; 222 223 // TODO(isolates): Technically this could be calculated directly from a 224 // pointer to StackGuard. 225 Isolate* isolate_; 226 ThreadLocal thread_local_; 227 228 friend class Isolate; 229 friend class StackLimitCheck; 230 friend class PostponeInterruptsScope; 231 232 DISALLOW_COPY_AND_ASSIGN(StackGuard); 233 }; 234 235 } // namespace internal 236 } // namespace v8 237 238 #endif // V8_EXECUTION_H_ 239
