Print stop message.

runtime/vm/assembler_ia32.cc

 // Copyright (c) 2011, 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/globals.h"
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/assembler.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
 #include "vm/runtime_entry.h"
+#include "vm/stub_code.h"
 
 namespace dart {
 
+DEFINE_FLAG(bool, print_stop_message, true, "Print stop message.");
+
+
 class DirectCallRelocation : public AssemblerFixup {
  public:
   void Process(const MemoryRegion& region, int position) {
     // Direct calls are relative to the following instruction on x86.
     int32_t pointer = region.Load<int32_t>(position);
     int32_t delta = region.start() + position + sizeof(int32_t);
     region.Store<int32_t>(position, pointer - delta);
   }
 };
 
@@ skipping 1406 matching lines @@
     int position = label->NearPosition();
     int offset = bound - (position + 1);
     ASSERT(Utils::IsInt(8, offset));
     buffer_.Store<int8_t>(position, offset);
   }
   label->BindTo(bound);
 }
 
 
 void Assembler::Stop(const char* message) {
-  // Emit the message address as immediate operand in the test rax instruction,
-  // followed by the int3 instruction.
-  // Execution can be resumed with the 'cont' command in gdb.
-  testl(EAX, Immediate(reinterpret_cast<int32_t>(message)));
-  int3();
+  if (FLAG_print_stop_message) {
+    pushl(EAX);  // Preserve EAX.
+    movl(EAX, Immediate(reinterpret_cast<int32_t>(message)));
+    call(&StubCode::PrintStopMessageLabel());  // Passing message in EAX.
+    popl(EAX);  // Restore EAX.
+  } else {
+    // Emit the message address as immediate operand in the test instruction.
+    testl(EAX, Immediate(reinterpret_cast<int32_t>(message)));
+  }
+  // Emit the int3 instruction.
+  int3();  // Execution can be resumed with the 'cont' command in gdb.
 }
 
 
 void Assembler::EmitOperand(int rm, const Operand& operand) {
   ASSERT(rm >= 0 && rm < 8);
   const int length = operand.length_;
   ASSERT(length > 0);
   // Emit the ModRM byte updated with the given RM value.
   ASSERT((operand.encoding_[0] & 0x38) == 0);
   EmitUint8(operand.encoding_[0] + (rm << 3));
@@ skipping 78 matching lines @@
                                  Register shifter) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   ASSERT(shifter == ECX);
   EmitUint8(0xD3);
   EmitOperand(rm, Operand(operand));
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32