Fix the stack limits setting API so it is usable.

src/execution.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 123 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(Handle<Object> object);
 };
 
 
 class ExecutionAccess;
 
 
-// Stack guards are used to limit the number of nested invocations of
-// JavaScript and the stack size used in each invocation.
-class StackGuard BASE_EMBEDDED {
+// 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 : public AllStatic {
  public:
-  StackGuard();
-
-  ~StackGuard();
-
+  // Pass the address beyond which the stack should not grow.  The stack
+  // is assumed to grow downwards.
   static void SetStackLimit(uintptr_t limit);
 
   static Address address_of_jslimit() {
     return reinterpret_cast<Address>(&thread_local_.jslimit_);
   }
 
   // Threading support.
   static char* ArchiveStackGuard(char* to);
   static char* RestoreStackGuard(char* from);
   static int ArchiveSpacePerThread();
   static void FreeThreadResources();
+  // Sets up the default stack guard for this thread if it has not
+  // already been set up.
+  static void InitThread(const ExecutionAccess& lock);
+  // Clears the stack guard for this thread so it does not look as if
+  // it has been set up.
+  static void ClearThread(const ExecutionAccess& lock);
 
   static bool IsStackOverflow();
   static bool IsPreempted();
   static void Preempt();
   static bool IsInterrupted();
   static void Interrupt();
   static bool IsTerminateExecution();
   static void TerminateExecution();
 #ifdef ENABLE_DEBUGGER_SUPPORT
   static bool IsDebugBreak();
   static void DebugBreak();
   static bool IsDebugCommand();
   static void DebugCommand();
 #endif
   static void Continue(InterruptFlag after_what);
 
+  // This provides an asynchronous read of the stack limit 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.
+  static uintptr_t climit() {
+    return thread_local_.climit_;
+  }
+
   static uintptr_t jslimit() {
     return thread_local_.jslimit_;
   }
 
  private:
   // You should hold the ExecutionAccess lock when calling this method.
   static bool IsSet(const ExecutionAccess& lock);
 
-  // This provides an asynchronous read of the stack limit 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.
-  static uintptr_t climit() {
-    return thread_local_.climit_;
-  }
-
   // You should hold the ExecutionAccess lock when calling this method.
   static void set_limits(uintptr_t value, const ExecutionAccess& lock) {
     Heap::SetStackLimit(value);
     thread_local_.jslimit_ = value;
     thread_local_.climit_ = value;
   }
 
   // Reset limits to initial values. For example after handling interrupt.
   // You should hold the ExecutionAccess lock when calling this method.
   static void reset_limits(const ExecutionAccess& lock) {
-    if (thread_local_.nesting_ == 0) {
-      // No limits have been set yet.
-      set_limits(kIllegalLimit, lock);
-    } else {
-      thread_local_.jslimit_ = thread_local_.initial_jslimit_;
-      Heap::SetStackLimit(thread_local_.jslimit_);
-      thread_local_.climit_ = thread_local_.initial_climit_;
-    }
+    thread_local_.jslimit_ = thread_local_.initial_jslimit_;
+    Heap::SetStackLimit(thread_local_.jslimit_);
+    thread_local_.climit_ = thread_local_.initial_climit_;
   }
 
   // Enable or disable interrupts.
   static void EnableInterrupts();
   static void DisableInterrupts();
 
   static const uintptr_t kLimitSize = kPointerSize * 128 * KB;
 #ifdef V8_TARGET_ARCH_X64
   static const uintptr_t kInterruptLimit = V8_UINT64_C(0xfffffffffffffffe);
-  static const uintptr_t kIllegalLimit = V8_UINT64_C(0xffffffffffffffff);
+  static const uintptr_t kIllegalLimit = V8_UINT64_C(0xfffffffffffffff8);
 #else
   static const uintptr_t kInterruptLimit = 0xfffffffe;
-  static const uintptr_t kIllegalLimit = 0xffffffff;
+  static const uintptr_t kIllegalLimit = 0xfffffff8;
 #endif
 
   class ThreadLocal {
    public:
-    ThreadLocal()
-      : initial_jslimit_(kIllegalLimit),
-        jslimit_(kIllegalLimit),
-        initial_climit_(kIllegalLimit),
-        climit_(kIllegalLimit),
-        nesting_(0),
-        postpone_interrupts_nesting_(0),
-        interrupt_flags_(0) {
-      Heap::SetStackLimit(kIllegalLimit);
-    }
+    ThreadLocal() { Clear(); }
+    // You should hold the ExecutionAccess lock when you call Initialize or
+    // Clear.
+    void Initialize();
+    void Clear();
     uintptr_t initial_jslimit_;
     uintptr_t jslimit_;
     uintptr_t initial_climit_;
     uintptr_t climit_;
     int nesting_;
     int postpone_interrupts_nesting_;
     int interrupt_flags_;
   };
 
   static ThreadLocal thread_local_;
@@ skipping 43 matching lines @@
       v8::Handle<v8::String> name);
   static v8::Handle<v8::Value> GC(const v8::Arguments& args);
  private:
   static const char* kSource;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_EXECUTION_H_