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 static Handle<String> GetStackTraceLine(Handle<Object> recv, 53 Handle<JSFunction> fun, 54 Handle<Object> pos, 55 Handle<Object> is_global); 56 }; 57 58 59 class ExecutionAccess; 60 class PostponeInterruptsScope; 61 62 63 // StackGuard contains the handling of the limits that are used to limit the 64 // number of nested invocations of JavaScript and the stack size used in each 65 // invocation. 66 class StackGuard final { 67 public: 68 // Pass the address beyond which the stack should not grow. The stack 69 // is assumed to grow downwards. 70 void SetStackLimit(uintptr_t limit); 71 72 // The simulator uses a separate JS stack. Limits on the JS stack might have 73 // to be adjusted in order to reflect overflows of the C stack, because we 74 // cannot rely on the interleaving of frames on the simulator. 75 void AdjustStackLimitForSimulator(); 76 77 // Threading support. 78 char* ArchiveStackGuard(char* to); 79 char* RestoreStackGuard(char* from); ArchiveSpacePerThread()80 static int ArchiveSpacePerThread() { return sizeof(ThreadLocal); } 81 void FreeThreadResources(); 82 // Sets up the default stack guard for this thread if it has not 83 // already been set up. 84 void InitThread(const ExecutionAccess& lock); 85 // Clears the stack guard for this thread so it does not look as if 86 // it has been set up. 87 void ClearThread(const ExecutionAccess& lock); 88 89 #define INTERRUPT_LIST(V) \ 90 V(DEBUGBREAK, DebugBreak, 0) \ 91 V(DEBUGCOMMAND, DebugCommand, 1) \ 92 V(TERMINATE_EXECUTION, TerminateExecution, 2) \ 93 V(GC_REQUEST, GC, 3) \ 94 V(INSTALL_CODE, InstallCode, 4) \ 95 V(API_INTERRUPT, ApiInterrupt, 5) \ 96 V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 6) 97 98 #define V(NAME, Name, id) \ 99 inline bool Check##Name() { return CheckInterrupt(NAME); } \ 100 inline void Request##Name() { RequestInterrupt(NAME); } \ 101 inline void Clear##Name() { ClearInterrupt(NAME); } 102 INTERRUPT_LIST(V) 103 #undef V 104 105 // Flag used to set the interrupt causes. 106 enum InterruptFlag { 107 #define V(NAME, Name, id) NAME = (1 << id), 108 INTERRUPT_LIST(V) 109 #undef V 110 #define V(NAME, Name, id) NAME | 111 ALL_INTERRUPTS = INTERRUPT_LIST(V) 0 112 #undef V 113 }; 114 climit()115 uintptr_t climit() { return thread_local_.climit(); } jslimit()116 uintptr_t jslimit() { return thread_local_.jslimit(); } 117 // This provides an asynchronous read of the stack limits for the current 118 // thread. There are no locks protecting this, but it is assumed that you 119 // have the global V8 lock if you are using multiple V8 threads. real_climit()120 uintptr_t real_climit() { 121 return thread_local_.real_climit_; 122 } real_jslimit()123 uintptr_t real_jslimit() { 124 return thread_local_.real_jslimit_; 125 } address_of_jslimit()126 Address address_of_jslimit() { 127 return reinterpret_cast<Address>(&thread_local_.jslimit_); 128 } address_of_real_jslimit()129 Address address_of_real_jslimit() { 130 return reinterpret_cast<Address>(&thread_local_.real_jslimit_); 131 } 132 133 // If the stack guard is triggered, but it is not an actual 134 // stack overflow, then handle the interruption accordingly. 135 Object* HandleInterrupts(); 136 void HandleGCInterrupt(); 137 138 private: 139 StackGuard(); 140 141 bool CheckInterrupt(InterruptFlag flag); 142 void RequestInterrupt(InterruptFlag flag); 143 void ClearInterrupt(InterruptFlag flag); 144 bool CheckAndClearInterrupt(InterruptFlag flag); 145 146 // You should hold the ExecutionAccess lock when calling this method. has_pending_interrupts(const ExecutionAccess & lock)147 bool has_pending_interrupts(const ExecutionAccess& lock) { 148 return thread_local_.interrupt_flags_ != 0; 149 } 150 151 // You should hold the ExecutionAccess lock when calling this method. 152 inline void set_interrupt_limits(const ExecutionAccess& lock); 153 154 // Reset limits to actual values. For example after handling interrupt. 155 // You should hold the ExecutionAccess lock when calling this method. 156 inline void reset_limits(const ExecutionAccess& lock); 157 158 // Enable or disable interrupts. 159 void EnableInterrupts(); 160 void DisableInterrupts(); 161 162 #if V8_TARGET_ARCH_64_BIT 163 static const uintptr_t kInterruptLimit = V8_UINT64_C(0xfffffffffffffffe); 164 static const uintptr_t kIllegalLimit = V8_UINT64_C(0xfffffffffffffff8); 165 #else 166 static const uintptr_t kInterruptLimit = 0xfffffffe; 167 static const uintptr_t kIllegalLimit = 0xfffffff8; 168 #endif 169 170 void PushPostponeInterruptsScope(PostponeInterruptsScope* scope); 171 void PopPostponeInterruptsScope(); 172 173 class ThreadLocal final { 174 public: ThreadLocal()175 ThreadLocal() { Clear(); } 176 // You should hold the ExecutionAccess lock when you call Initialize or 177 // Clear. 178 void Clear(); 179 180 // Returns true if the heap's stack limits should be set, false if not. 181 bool Initialize(Isolate* isolate); 182 183 // The stack limit is split into a JavaScript and a C++ stack limit. These 184 // two are the same except when running on a simulator where the C++ and 185 // JavaScript stacks are separate. Each of the two stack limits have two 186 // values. The one eith the real_ prefix is the actual stack limit 187 // set for the VM. The one without the real_ prefix has the same value as 188 // the actual stack limit except when there is an interruption (e.g. debug 189 // break or preemption) in which case it is lowered to make stack checks 190 // fail. Both the generated code and the runtime system check against the 191 // one without the real_ prefix. 192 uintptr_t real_jslimit_; // Actual JavaScript stack limit set for the VM. 193 uintptr_t real_climit_; // Actual C++ stack limit set for the VM. 194 195 // jslimit_ and climit_ can be read without any lock. 196 // Writing requires the ExecutionAccess lock. 197 base::AtomicWord jslimit_; 198 base::AtomicWord climit_; 199 jslimit()200 uintptr_t jslimit() { 201 return bit_cast<uintptr_t>(base::NoBarrier_Load(&jslimit_)); 202 } set_jslimit(uintptr_t limit)203 void set_jslimit(uintptr_t limit) { 204 return base::NoBarrier_Store(&jslimit_, 205 static_cast<base::AtomicWord>(limit)); 206 } climit()207 uintptr_t climit() { 208 return bit_cast<uintptr_t>(base::NoBarrier_Load(&climit_)); 209 } set_climit(uintptr_t limit)210 void set_climit(uintptr_t limit) { 211 return base::NoBarrier_Store(&climit_, 212 static_cast<base::AtomicWord>(limit)); 213 } 214 215 PostponeInterruptsScope* postpone_interrupts_; 216 int interrupt_flags_; 217 }; 218 219 // TODO(isolates): Technically this could be calculated directly from a 220 // pointer to StackGuard. 221 Isolate* isolate_; 222 ThreadLocal thread_local_; 223 224 friend class Isolate; 225 friend class StackLimitCheck; 226 friend class PostponeInterruptsScope; 227 228 DISALLOW_COPY_AND_ASSIGN(StackGuard); 229 }; 230 231 } // namespace internal 232 } // namespace v8 233 234 #endif // V8_EXECUTION_H_ 235