Use a breakpoint instruction for a stop message on arm instead of

runtime/vm/assembler_arm.cc

 // Copyright (c) 2013, 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"  // NOLINT
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/longjump.h"
@@ skipping 1452 matching lines @@
                       QRegister qd, QRegister qn, QRegister qm) {
   EmitSIMDqqq(B24 | B9 | B8, sz, qd, qn, qm);
 }
 
 
 void Assembler::vcgtqs(QRegister qd, QRegister qn, QRegister qm) {
   EmitSIMDqqq(B24 | B21 | B11 | B10 | B9, kSWord, qd, qn, qm);
 }
 
 
 void Assembler::svc(uint32_t imm24, Condition cond) {

[zra, 2015/04/22 19:39:25]

If this should only be used if we are using the simulator, you can and an ASSERT
for that here. Same for hlt on arm64.

[regis, 2015/04/22 20:28:35]

Good idea. I actually removed the assembler methods svc() and hlt(), since they
are only used as constant instructions in the simulator and never emitted via
the assembler.

   ASSERT(cond != kNoCondition);
   ASSERT(imm24 < (1 << 24));
   int32_t encoding = (cond << kConditionShift) | B27 | B26 | B25 | B24 | imm24;
   Emit(encoding);
 }
 
 
 void Assembler::bkpt(uint16_t imm16) {
   // bkpt requires that the cond field is AL.
   int32_t encoding = (AL << kConditionShift) | B24 | B21 |
@@ skipping 1993 matching lines @@
     BranchLink(&stub_code->PrintStopMessageLabel());  // Passing message in R0.
     PopList((1 << R0) | (1 << IP) | (1 << LR));  // Restore R0, IP, LR.
   }
   // Emit the message address before the svc instruction, so that we can
   // 'unstop' and continue execution in the simulator or jump to the next
   // instruction in gdb.
   Label stop;
   b(&stop);
   Emit(reinterpret_cast<int32_t>(message));
   Bind(&stop);
-  svc(kStopMessageSvcCode);
+  bkpt(Instr::kStopMessageCode);
 }
 
 
 Address Assembler::ElementAddressForIntIndex(bool is_load,
                                              bool is_external,
                                              intptr_t cid,
                                              intptr_t index_scale,
                                              Register array,
                                              intptr_t index,
                                              Register temp) {
@@ skipping 78 matching lines @@
 
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfFpuRegisters));
   return fpu_reg_names[reg];
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM