Add mechanism to postpone interrupts selectively.

src/execution.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_EXECUTION_H_
 #define V8_EXECUTION_H_
 
 #include "src/handles.h"
 
 namespace v8 {
@@ skipping 104 matching lines @@
   // Get a function delegate (or undefined) for the given non-function
   // object. Used for support calling objects as constructors.
   static Handle<Object> GetConstructorDelegate(Isolate* isolate,
                                                Handle<Object> object);
   static MaybeHandle<Object> TryGetConstructorDelegate(Isolate* isolate,
                                                        Handle<Object> object);
 };
 
 
 class ExecutionAccess;
+class PostponeInterruptsScope;
 
 
 // StackGuard contains the handling of the limits that are used to limit the
 // number of nested invocations of JavaScript and the stack size used in each
 // invocation.
 class StackGuard V8_FINAL {
  public:
   // Pass the address beyond which the stack should not grow.  The stack
   // is assumed to grow downwards.
   void SetStackLimit(uintptr_t limit);
 
   // Threading support.
   char* ArchiveStackGuard(char* to);
   char* RestoreStackGuard(char* from);
   static int ArchiveSpacePerThread() { return sizeof(ThreadLocal); }
   void FreeThreadResources();
   // Sets up the default stack guard for this thread if it has not
   // already been set up.
   void InitThread(const ExecutionAccess& lock);
   // Clears the stack guard for this thread so it does not look as if
   // it has been set up.
   void ClearThread(const ExecutionAccess& lock);
 
-#define INTERRUPT_LIST(V)                                       \
-  V(DEBUGBREAK, DebugBreak)                                     \
-  V(DEBUGCOMMAND, DebugCommand)                                 \
-  V(TERMINATE_EXECUTION, TerminateExecution)                    \
-  V(GC_REQUEST, GC)                                             \
-  V(INSTALL_CODE, InstallCode)                                  \
-  V(API_INTERRUPT, ApiInterrupt)                                \
-  V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites)
+#define INTERRUPT_LIST(V)                                          \
+  V(DEBUGBREAK, DebugBreak, 0)                                     \
+  V(DEBUGCOMMAND, DebugCommand, 1)                                 \
+  V(TERMINATE_EXECUTION, TerminateExecution, 2)                    \
+  V(GC_REQUEST, GC, 3)                                             \
+  V(INSTALL_CODE, InstallCode, 4)                                  \
+  V(API_INTERRUPT, ApiInterrupt, 5)                                \
+  V(DEOPT_MARKED_ALLOCATION_SITES, DeoptMarkedAllocationSites, 6)
 
-#define V(NAME, Name)                                              \
-  inline bool Check##Name() { return CheckInterrupt(1 << NAME); }  \
-  inline void Request##Name() { RequestInterrupt(1 << NAME); }     \
-  inline void Clear##Name() { ClearInterrupt(1 << NAME); }
+#define V(NAME, Name, id)                                          \
+  inline bool Check##Name() { return CheckInterrupt(NAME); }  \
+  inline void Request##Name() { RequestInterrupt(NAME); }     \
+  inline void Clear##Name() { ClearInterrupt(NAME); }
   INTERRUPT_LIST(V)
 #undef V
 
+  // Flag used to set the interrupt causes.
+  enum InterruptFlag {
+  #define V(NAME, Name, id) NAME = (1 << id),
+    INTERRUPT_LIST(V)
+  #undef V
+  #define V(NAME, Name, id) NAME |
+    ALL_INTERRUPTS = INTERRUPT_LIST(V) 0
+  #undef V
+  };
+
   // This provides an asynchronous read of the stack limits for the current
   // thread.  There are no locks protecting this, but it is assumed that you
   // have the global V8 lock if you are using multiple V8 threads.
   uintptr_t climit() {
     return thread_local_.climit_;
   }
   uintptr_t real_climit() {
     return thread_local_.real_climit_;
   }
   uintptr_t jslimit() {
     return thread_local_.jslimit_;
   }
   uintptr_t real_jslimit() {
     return thread_local_.real_jslimit_;
   }
   Address address_of_jslimit() {
     return reinterpret_cast<Address>(&thread_local_.jslimit_);
   }
   Address address_of_real_jslimit() {
     return reinterpret_cast<Address>(&thread_local_.real_jslimit_);
   }
 
   // If the stack guard is triggered, but it is not an actual
   // stack overflow, then handle the interruption accordingly.
   Object* HandleInterrupts();
 
  private:
   StackGuard();
 
-// Flag used to set the interrupt causes.
-enum InterruptFlag {
-#define V(NAME, Name) NAME,
-  INTERRUPT_LIST(V)
-#undef V
-  NUMBER_OF_INTERRUPTS
-};
-
-  bool CheckInterrupt(int flagbit);
-  void RequestInterrupt(int flagbit);
-  void ClearInterrupt(int flagbit);
+  bool CheckInterrupt(InterruptFlag flag);
+  void RequestInterrupt(InterruptFlag flag);
+  void ClearInterrupt(InterruptFlag flag);
   bool CheckAndClearInterrupt(InterruptFlag flag);
 
   // You should hold the ExecutionAccess lock when calling this method.
   bool has_pending_interrupts(const ExecutionAccess& lock) {
-    // Sanity check: We shouldn't be asking about pending interrupts
-    // unless we're not postponing them anymore.
-    ASSERT(!should_postpone_interrupts(lock));
     return thread_local_.interrupt_flags_ != 0;
   }
 
   // You should hold the ExecutionAccess lock when calling this method.
-  bool should_postpone_interrupts(const ExecutionAccess& lock) {
-    return thread_local_.postpone_interrupts_nesting_ > 0;
-  }
-
-  // You should hold the ExecutionAccess lock when calling this method.
   inline void set_interrupt_limits(const ExecutionAccess& lock);
 
   // Reset limits to actual values. For example after handling interrupt.
   // You should hold the ExecutionAccess lock when calling this method.
   inline void reset_limits(const ExecutionAccess& lock);
 
   // Enable or disable interrupts.
   void EnableInterrupts();
   void DisableInterrupts();
 
 #if V8_TARGET_ARCH_64_BIT
   static const uintptr_t kInterruptLimit = V8_UINT64_C(0xfffffffffffffffe);
   static const uintptr_t kIllegalLimit = V8_UINT64_C(0xfffffffffffffff8);
 #else
   static const uintptr_t kInterruptLimit = 0xfffffffe;
   static const uintptr_t kIllegalLimit = 0xfffffff8;
 #endif
 
+  void PushPostponeInterruptsScope(PostponeInterruptsScope* scope);
+  void PopPostponeInterruptsScope();
+
   class ThreadLocal V8_FINAL {
    public:
     ThreadLocal() { Clear(); }
     // You should hold the ExecutionAccess lock when you call Initialize or
     // Clear.
     void Clear();
 
     // Returns true if the heap's stack limits should be set, false if not.
     bool Initialize(Isolate* isolate);
 
     // The stack limit is split into a JavaScript and a C++ stack limit. These
     // two are the same except when running on a simulator where the C++ and
     // JavaScript stacks are separate. Each of the two stack limits have two
     // values. The one eith the real_ prefix is the actual stack limit
     // set for the VM. The one without the real_ prefix has the same value as
     // the actual stack limit except when there is an interruption (e.g. debug
     // break or preemption) in which case it is lowered to make stack checks
     // fail. Both the generated code and the runtime system check against the
     // one without the real_ prefix.
     uintptr_t real_jslimit_;  // Actual JavaScript stack limit set for the VM.
     uintptr_t jslimit_;
     uintptr_t real_climit_;  // Actual C++ stack limit set for the VM.
     uintptr_t climit_;
 
-    int nesting_;
-    int postpone_interrupts_nesting_;
+    PostponeInterruptsScope* postpone_interrupts_;
     int interrupt_flags_;
   };
 
   class StackPointer {
    public:
     inline uintptr_t address() { return reinterpret_cast<uintptr_t>(this); }
   };
 
   // TODO(isolates): Technically this could be calculated directly from a
   //                 pointer to StackGuard.
   Isolate* isolate_;
   ThreadLocal thread_local_;
 
   friend class Isolate;
   friend class StackLimitCheck;
   friend class PostponeInterruptsScope;
 
   DISALLOW_COPY_AND_ASSIGN(StackGuard);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_EXECUTION_H_