MIPS: Fix an invalid stack-check in the simulator.

src/mips/simulator-mips.cc

 // Copyright 2011 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 1391 matching lines @@
   int32_t func = instr->FunctionFieldRaw();
   uint32_t code = (func == BREAK) ? instr->Bits(25, 6) : -1;
 
   // We first check if we met a call_rt_redirected.
   if (instr->InstructionBits() == rtCallRedirInstr) {
     Redirection* redirection = Redirection::FromSwiInstruction(instr);
     int32_t arg0 = get_register(a0);
     int32_t arg1 = get_register(a1);
     int32_t arg2 = get_register(a2);
     int32_t arg3 = get_register(a3);
-    int32_t arg4 = 0;
-    int32_t arg5 = 0;
 
-    // Need to check if sp is valid before assigning arg4, arg5.
-    // This is a fix for cctest test-api/CatchStackOverflow which causes
-    // the stack to overflow. For some reason arm doesn't need this
-    // stack check here.
     int32_t* stack_pointer = reinterpret_cast<int32_t*>(get_register(sp));
-    int32_t* stack = reinterpret_cast<int32_t*>(stack_);
-    if (stack_pointer >= stack && stack_pointer < stack + stack_size_ - 5) {
-      // Args 4 and 5 are on the stack after the reserved space for args 0..3.
-      arg4 = stack_pointer[4];
-      arg5 = stack_pointer[5];
-    }
+    // Args 4 and 5 are on the stack after the reserved space for args 0..3.
+    int32_t arg4 = stack_pointer[4];
+    int32_t arg5 = stack_pointer[5];
 
     bool fp_call =
          (redirection->type() == ExternalReference::BUILTIN_FP_FP_CALL) ||
          (redirection->type() == ExternalReference::BUILTIN_COMPARE_CALL) ||
          (redirection->type() == ExternalReference::BUILTIN_FP_CALL) ||
          (redirection->type() == ExternalReference::BUILTIN_FP_INT_CALL);
 
     if (!IsMipsSoftFloatABI) {
       // With the hard floating point calling convention, double
       // arguments are passed in FPU registers. Fetch the arguments
@@ skipping 1385 matching lines @@
 }
 
 
 #undef UNSUPPORTED
 
 } }  // namespace v8::internal
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_MIPS