Remove --check-stack flag from V8.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
===================================================================
--- src/x64/builtins-x64.cc	(revision 3148)
+++ src/x64/builtins-x64.cc	(working copy)
@@ -318,47 +318,47 @@
   __ push(Operand(rbp, kArgumentsOffset));
   __ InvokeBuiltin(Builtins::APPLY_PREPARE, CALL_FUNCTION);
 
-  if (FLAG_check_stack) {
-    // We need to catch preemptions right here, otherwise an unlucky preemption
-    // could show up as a failed apply.
-    Label retry_preemption;
-    Label no_preemption;
-    __ bind(&retry_preemption);
-    ExternalReference stack_guard_limit =
-        ExternalReference::address_of_stack_guard_limit();
-    __ movq(kScratchRegister, stack_guard_limit);
-    __ movq(rcx, rsp);
-    __ subq(rcx, Operand(kScratchRegister, 0));
-    // rcx contains the difference between the stack limit and the stack top.
-    // We use it below to check that there is enough room for the arguments.
-    __ j(above, &no_preemption);
+  // Check the stack for overflow or a break request.
+  // We need to catch preemptions right here, otherwise an unlucky preemption
+  // could show up as a failed apply.
+  Label retry_preemption;
+  Label no_preemption;
+  __ bind(&retry_preemption);
+  ExternalReference stack_guard_limit =
+      ExternalReference::address_of_stack_guard_limit();
+  __ movq(kScratchRegister, stack_guard_limit);
+  __ movq(rcx, rsp);
+  __ subq(rcx, Operand(kScratchRegister, 0));
+  // rcx contains the difference between the stack limit and the stack top.
+  // We use it below to check that there is enough room for the arguments.
+  __ j(above, &no_preemption);
 
-    // Preemption!
-    // Because runtime functions always remove the receiver from the stack, we
-    // have to fake one to avoid underflowing the stack.
-    __ push(rax);
-    __ Push(Smi::FromInt(0));
+  // Preemption!
+  // Because runtime functions always remove the receiver from the stack, we
+  // have to fake one to avoid underflowing the stack.
+  __ push(rax);
+  __ Push(Smi::FromInt(0));
 
-    // Do call to runtime routine.
-    __ CallRuntime(Runtime::kStackGuard, 1);
-    __ pop(rax);
-    __ jmp(&retry_preemption);
+  // Do call to runtime routine.
+  __ CallRuntime(Runtime::kStackGuard, 1);
+  __ pop(rax);
+  __ jmp(&retry_preemption);
 
-    __ bind(&no_preemption);
+  __ bind(&no_preemption);
 
-    Label okay;
-    // Make rdx the space we need for the array when it is unrolled onto the
-    // stack.
-    __ PositiveSmiTimesPowerOfTwoToInteger64(rdx, rax, kPointerSizeLog2);
-    __ cmpq(rcx, rdx);
-    __ j(greater, &okay);
+  Label okay;
+  // Make rdx the space we need for the array when it is unrolled onto the
+  // stack.
+  __ PositiveSmiTimesPowerOfTwoToInteger64(rdx, rax, kPointerSizeLog2);
+  __ cmpq(rcx, rdx);
+  __ j(greater, &okay);
 
-    // Too bad: Out of stack space.
-    __ push(Operand(rbp, kFunctionOffset));
-    __ push(rax);
-    __ InvokeBuiltin(Builtins::APPLY_OVERFLOW, CALL_FUNCTION);
-    __ bind(&okay);
-  }
+  // Too bad: Out of stack space.
+  __ push(Operand(rbp, kFunctionOffset));
+  __ push(rax);
+  __ InvokeBuiltin(Builtins::APPLY_OVERFLOW, CALL_FUNCTION);
+  __ bind(&okay);
+  // End of stack check.
 
   // Push current index and limit.
   const int kLimitOffset =