* Make stack/preemption guard faster on ARM by putting stack...

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 157 matching lines @@
   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);
 
+  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_;
     }
   }
 
   // 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);
 #else
   static const uintptr_t kInterruptLimit = 0xfffffffe;
   static const uintptr_t kIllegalLimit = 0xffffffff;
 #endif
 
   class ThreadLocal {
    public:
     ThreadLocal()
      : initial_jslimit_(kIllegalLimit),

[Mads Ager (chromium), 2009/08/26 10:09:28]

I know this has not been introduced in this change, but could you change this to
a four space indent.

        jslimit_(kIllegalLimit),
        initial_climit_(kIllegalLimit),
        climit_(kIllegalLimit),
        nesting_(0),
        postpone_interrupts_nesting_(0),
-       interrupt_flags_(0) {}
+       interrupt_flags_(0) {
+      Heap::SetStackLimit(kIllegalLimit);
+    }
     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_