Fix flag to switch write protection of code pages on/off.

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 52 matching lines @@
 DEFINE_FLAG(bool, use_lib_cache, true, "Use library name cache");
 
 DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, error_on_bad_override);
 DECLARE_FLAG(bool, trace_compiler);
 DECLARE_FLAG(bool, trace_deoptimization);
 DECLARE_FLAG(bool, trace_deoptimization_verbose);
 DECLARE_FLAG(bool, verbose_stacktrace);
 DECLARE_FLAG(charp, coverage_dir);
+DECLARE_FLAG(bool, write_protect_code);
 
 static const char* kGetterPrefix = "get:";
 static const intptr_t kGetterPrefixLength = strlen(kGetterPrefix);
 static const char* kSetterPrefix = "set:";
 static const intptr_t kSetterPrefixLength = strlen(kSetterPrefix);
 
 cpp_vtable Object::handle_vtable_ = 0;
 cpp_vtable Object::builtin_vtables_[kNumPredefinedCids] = { 0 };
 cpp_vtable Smi::handle_vtable_ = 0;
 
@@ skipping 10138 matching lines @@
       instrs.set_object_pool(Object::empty_array().raw());
     } else {
       // TODO(regis): Once MakeArray takes a Heap::Space argument, call it here
       // with Heap::kOld and change the ARM and MIPS assemblers to work with a
       // GrowableObjectArray in new space.
       instrs.set_object_pool(Array::MakeArray(object_pool));
     }
     bool status =
         VirtualMemory::Protect(reinterpret_cast<void*>(instrs.raw_ptr()),
                                instrs.raw()->Size(),
-                               VirtualMemory::kReadExecute);
+                               FLAG_write_protect_code
+                                   ? VirtualMemory::kReadExecute
+                                   : VirtualMemory::kReadWriteExecute);
     ASSERT(status);
   }
   return code.raw();
 }
 
 
 RawCode* Code::FinalizeCode(const Function& function,
                             Assembler* assembler,
                             bool optimized) {
   // Calling ToFullyQualifiedCString is very expensive, try to avoid it.
@@ skipping 7114 matching lines @@
   return "_MirrorReference";
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   Instance::PrintToJSONStream(stream, ref);
 }
 
 
 }  // namespace dart