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 V8_EXPORT_PRIVATE MUST_USE_RESULT static MaybeHandle<Object> Call( 25 Isolate* isolate, Handle<Object> callable, Handle<Object> receiver, 26 int argc, Handle<Object> argv[]); 27 28 // Construct object from function, the caller supplies an array of 29 // arguments. 30 MUST_USE_RESULT static MaybeHandle<Object> New(Handle<JSFunction> constructor, 31 int argc, 32 Handle<Object> argv[]); 33 MUST_USE_RESULT static MaybeHandle<Object> New(Isolate* isolate, 34 Handle<Object> constructor, 35 Handle<Object> new_target, 36 int argc, 37 Handle<Object> argv[]); 38 39 // Call a function, just like Call(), but make sure to silently catch 40 // any thrown exceptions. The return value is either the result of 41 // calling the function (if caught exception is false) or the exception 42 // that occurred (if caught exception is true). 43 // In the exception case, exception_out holds the caught exceptions, unless 44 // it is a termination exception. 45 static MaybeHandle<Object> TryCall(Isolate* isolate, Handle<Object> callable, 46 Handle<Object> receiver, int argc, 47 Handle<Object> argv[], 48 MaybeHandle<Object>* exception_out = NULL); 49 }; 50 51 52 class ExecutionAccess; 53 class PostponeInterruptsScope; 54 55 56 // StackGuard contains the handling of the limits that are used to limit the 57 // number of nested invocations of JavaScript and the stack size used in each 58 // invocation. 59 class StackGuard final { 60 public: 61 // Pass the address beyond which the stack should not grow. The stack 62 // is assumed to grow downwards. 63 void SetStackLimit(uintptr_t limit); 64 65 // The simulator uses a separate JS stack. Limits on the JS stack might have 66 // to be adjusted in order to reflect overflows of the C stack, because we 67 // cannot rely on the interleaving of frames on the simulator. 68 void AdjustStackLimitForSimulator(); 69 70 // Threading support. 71 char* ArchiveStackGuard(char* to); 72 char* RestoreStackGuard(char* from); 73 static int ArchiveSpacePerThread() { return sizeof(ThreadLocal); } 74 void FreeThreadResources(); 75 // Sets up the default stack guard for this thread if it has not 76 // already been set up. 77 void InitThread(const ExecutionAccess& lock); 78 // Clears the stack guard for this thread so it does not look as if 79 // it has been set up. 80 void ClearThread(const ExecutionAccess& lock); 81 82 #define INTERRUPT_LIST(V) \ 83 V(DEBUGBREAK, DebugBreak, 0) \ 84 V(DEBUGCOMMAND, DebugCommand, 1) \ 85 V(TERMINATE_EXECUTION, TerminateExecution, 2) \ 86 V(GC_REQUEST, GC, 3) \ 87 V(INSTALL_CODE, InstallCode, 4) \ 88 V(API_INTERRUPT, ApiInterrupt, 5) \ 89 V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 6) 90 91 #define V(NAME, Name, id) \ 92 inline bool Check##Name() { return CheckInterrupt(NAME); } \ 93 inline void Request##Name() { RequestInterrupt(NAME); } \ 94 inline void Clear##Name() { ClearInterrupt(NAME); } 95 INTERRUPT_LIST(V) 96 #undef V 97 98 // Flag used to set the interrupt causes. 99 enum InterruptFlag { 100 #define V(NAME, Name, id) NAME = (1 << id), 101 INTERRUPT_LIST(V) 102 #undef V 103 #define V(NAME, Name, id) NAME | 104 ALL_INTERRUPTS = INTERRUPT_LIST(V) 0 105 #undef V 106 }; 107 108 uintptr_t climit() { return thread_local_.climit(); } 109 uintptr_t jslimit() { return thread_local_.jslimit(); } 110 // This provides an asynchronous read of the stack limits for the current 111 // thread. There are no locks protecting this, but it is assumed that you 112 // have the global V8 lock if you are using multiple V8 threads. 113 uintptr_t real_climit() { 114 return thread_local_.real_climit_; 115 } 116 uintptr_t real_jslimit() { 117 return thread_local_.real_jslimit_; 118 } 119 Address address_of_jslimit() { 120 return reinterpret_cast<Address>(&thread_local_.jslimit_); 121 } 122 Address address_of_real_jslimit() { 123 return reinterpret_cast<Address>(&thread_local_.real_jslimit_); 124 } 125 126 // If the stack guard is triggered, but it is not an actual 127 // stack overflow, then handle the interruption accordingly. 128 Object* HandleInterrupts(); 129 void HandleGCInterrupt(); 130 131 private: 132 StackGuard(); 133 134 bool CheckInterrupt(InterruptFlag flag); 135 void RequestInterrupt(InterruptFlag flag); 136 void ClearInterrupt(InterruptFlag flag); 137 bool CheckAndClearInterrupt(InterruptFlag flag); 138 139 // You should hold the ExecutionAccess lock when calling this method. 140 bool has_pending_interrupts(const ExecutionAccess& lock) { 141 return thread_local_.interrupt_flags_ != 0; 142 } 143 144 // You should hold the ExecutionAccess lock when calling this method. 145 inline void set_interrupt_limits(const ExecutionAccess& lock); 146 147 // Reset limits to actual values. For example after handling interrupt. 148 // You should hold the ExecutionAccess lock when calling this method. 149 inline void reset_limits(const ExecutionAccess& lock); 150 151 // Enable or disable interrupts. 152 void EnableInterrupts(); 153 void DisableInterrupts(); 154 155 #if V8_TARGET_ARCH_64_BIT 156 static const uintptr_t kInterruptLimit = V8_UINT64_C(0xfffffffffffffffe); 157 static const uintptr_t kIllegalLimit = V8_UINT64_C(0xfffffffffffffff8); 158 #else 159 static const uintptr_t kInterruptLimit = 0xfffffffe; 160 static const uintptr_t kIllegalLimit = 0xfffffff8; 161 #endif 162 163 void PushPostponeInterruptsScope(PostponeInterruptsScope* scope); 164 void PopPostponeInterruptsScope(); 165 166 class ThreadLocal final { 167 public: 168 ThreadLocal() { Clear(); } 169 // You should hold the ExecutionAccess lock when you call Initialize or 170 // Clear. 171 void Clear(); 172 173 // Returns true if the heap's stack limits should be set, false if not. 174 bool Initialize(Isolate* isolate); 175 176 // The stack limit is split into a JavaScript and a C++ stack limit. These 177 // two are the same except when running on a simulator where the C++ and 178 // JavaScript stacks are separate. Each of the two stack limits have two 179 // values. The one eith the real_ prefix is the actual stack limit 180 // set for the VM. The one without the real_ prefix has the same value as 181 // the actual stack limit except when there is an interruption (e.g. debug 182 // break or preemption) in which case it is lowered to make stack checks 183 // fail. Both the generated code and the runtime system check against the 184 // one without the real_ prefix. 185 uintptr_t real_jslimit_; // Actual JavaScript stack limit set for the VM. 186 uintptr_t real_climit_; // Actual C++ stack limit set for the VM. 187 188 // jslimit_ and climit_ can be read without any lock. 189 // Writing requires the ExecutionAccess lock. 190 base::AtomicWord jslimit_; 191 base::AtomicWord climit_; 192 193 uintptr_t jslimit() { 194 return bit_cast<uintptr_t>(base::NoBarrier_Load(&jslimit_)); 195 } 196 void set_jslimit(uintptr_t limit) { 197 return base::NoBarrier_Store(&jslimit_, 198 static_cast<base::AtomicWord>(limit)); 199 } 200 uintptr_t climit() { 201 return bit_cast<uintptr_t>(base::NoBarrier_Load(&climit_)); 202 } 203 void set_climit(uintptr_t limit) { 204 return base::NoBarrier_Store(&climit_, 205 static_cast<base::AtomicWord>(limit)); 206 } 207 208 PostponeInterruptsScope* postpone_interrupts_; 209 int interrupt_flags_; 210 }; 211 212 // TODO(isolates): Technically this could be calculated directly from a 213 // pointer to StackGuard. 214 Isolate* isolate_; 215 ThreadLocal thread_local_; 216 217 friend class Isolate; 218 friend class StackLimitCheck; 219 friend class PostponeInterruptsScope; 220 221 DISALLOW_COPY_AND_ASSIGN(StackGuard); 222 }; 223 224 } // namespace internal 225 } // namespace v8 226 227 #endif // V8_EXECUTION_H_ 228
