A64: Don't use a 'debug' instruction to implement the 'trace_sim' option.

src/a64/simulator-a64.cc

 // Copyright 2013 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 354 matching lines @@
   stack_size_ = (FLAG_sim_stack_size * KB) + (2 * stack_protection_size_);
   stack_ = new byte[stack_size_];
   stack_limit_ = stack_ + stack_protection_size_;
   byte* tos = stack_ + stack_size_ - stack_protection_size_;
   // The stack pointer must be 16 bytes aligned.
   set_sp(reinterpret_cast<int64_t>(tos) & ~0xfUL);
 
   stream_ = stream;
   print_disasm_ = new PrintDisassembler(stream_);
 
+  if (FLAG_trace_sim) {
+    decoder_->InsertVisitorBefore(print_disasm_, this);
+    log_parameters_ = LOG_ALL;
+  }
+
   // The debugger needs to disassemble code without the simulator executing an
   // instruction, so we create a dedicated decoder.
   disassembler_decoder_ = new Decoder();
   disassembler_decoder_->AppendVisitor(print_disasm_);
 
   if (FLAG_log_instruction_stats) {
     instrument_ = new Instrument(FLAG_log_instruction_file,
                                  FLAG_log_instruction_period);
     decoder_->AppendVisitor(instrument_);
   }
@@ skipping 2683 matching lines @@
             PrintF("%sDebugger hit %d.%s\n",
                    clr_debug_number,
                    code,
                    clr_normal);
           }
         }
 
         // Other options.
         switch (parameters & kDebuggerTracingDirectivesMask) {
           case TRACE_ENABLE:
-            // Only enable tracing if the trace_sim flag is set.
-            if (FLAG_trace_sim) {
-              set_log_parameters(log_parameters() | parameters);
-              if (parameters & LOG_SYS_REGS) { PrintSystemRegisters(); }
-              if (parameters & LOG_REGS) { PrintRegisters(); }
-              if (parameters & LOG_FP_REGS) { PrintFPRegisters(); }
-            }
+            set_log_parameters(log_parameters() | parameters);
+            if (parameters & LOG_SYS_REGS) { PrintSystemRegisters(); }
+            if (parameters & LOG_REGS) { PrintRegisters(); }
+            if (parameters & LOG_FP_REGS) { PrintFPRegisters(); }
             break;
           case TRACE_DISABLE:
             set_log_parameters(log_parameters() & ~parameters);
             break;
           case TRACE_OVERRIDE:
             set_log_parameters(parameters);
             break;
           default:
             // We don't support a one-shot LOG_DISASM.
             ASSERT((parameters & LOG_DISASM) == 0);
@@ skipping 318 matching lines @@
     default:
       UNIMPLEMENTED();
   }
 }
 
 #endif  // USE_SIMULATOR
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64