Commit: Export AArch64 sum's single step function

[Nick Clifton <nickc at redhat dot com>]

Hi Guys,

  I am checking in the patch below to export the AArch64 sim's single
  step function, so that it can be used when a tool needs to just
  execute one instruction at a time.  The patch also fixes a minor bug
  in sim_create_inferior which would seg-fault if called without an
  initialised bfd object.

Cheers
  Nick

sim/ChangeLog
2016-08-11  Nick Clifton  <nickc@redhat.com>

	* interp.c (sim_create_inferior): Allow for being called with a
	NULL abfd parameter.  If a bfd is provided, initialise the sim
	with that start address.
	* simulator.c (HALT_NYI): Just print out the numeric value of the
	instruction when not tracing.
	(aarch64_step): Change from static to global.
	* simulator.h: Add a prototype for aarch64_step().

diff --git a/sim/aarch64/interp.c b/sim/aarch64/interp.c
index 8ae78c4..2a3ff26 100644
--- a/sim/aarch64/interp.c
+++ b/sim/aarch64/interp.c
@@ -135,7 +135,7 @@ sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
 		     char * const *argv, char * const *env)
 {
   sim_cpu *cpu = STATE_CPU (sd, 0);
-  long storage;
+  long storage = 0;
   bfd_vma addr = 0;
 
   if (abfd != NULL)
@@ -154,7 +154,8 @@ sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
       STATE_PROG_ARGV (sd) = dupargv (argv);
     }
 
-  storage = bfd_get_symtab_upper_bound (abfd);
+  if (abfd != NULL)
+    storage = bfd_get_symtab_upper_bound (abfd);
   if (storage > 0)
     {
       symtab = (asymbol **) xmalloc (storage);
@@ -163,7 +164,7 @@ sim_create_inferior (SIM_DESC sd, struct bfd *abfd,
       qsort (symtab, symcount, sizeof (asymbol *), compare_symbols);
     }
 
-  aarch64_init (cpu, bfd_get_start_address (abfd));
+  aarch64_init (cpu, addr);
 
   return SIM_RC_OK;
 }
@@ -332,7 +333,6 @@ sim_open (SIM_OPEN_KIND                  kind,
 	  struct bfd *                   abfd,
 	  char * const *                 argv)
 {
-  int i;
   sim_cpu *cpu;
   SIM_DESC sd = sim_state_alloc (kind, callback);
 
diff --git a/sim/aarch64/simulator.c b/sim/aarch64/simulator.c
index 45844e2..150bf34 100644
--- a/sim/aarch64/simulator.c
+++ b/sim/aarch64/simulator.c
@@ -64,10 +64,8 @@
 		  " exe addr %" PRIx64,					\
 		  __LINE__, aarch64_get_PC (cpu));			\
       if (! TRACE_ANY_P (cpu))						\
-	{								\
-	  sim_io_eprintf (CPU_STATE (cpu), "SIM Error: Unimplemented instruction: "); \
-	  trace_disasm (CPU_STATE (cpu), cpu, aarch64_get_PC (cpu));	\
-	}								\
+        sim_io_eprintf (CPU_STATE (cpu), "SIM Error: Unimplemented instruction: %#08x\n", \
+                        aarch64_get_instr (cpu));			\
       sim_engine_halt (CPU_STATE (cpu), cpu, NULL, aarch64_get_PC (cpu),\
 		       sim_stopped, SIM_SIGABRT);			\
     }									\
@@ -14074,7 +14072,7 @@ aarch64_decode_and_execute (sim_cpu *cpu, uint64_t pc)
     }
 }
 
-static bfd_boolean
+bfd_boolean
 aarch64_step (sim_cpu *cpu)
 {
   uint64_t pc = aarch64_get_PC (cpu);
diff --git a/sim/aarch64/simulator.h b/sim/aarch64/simulator.h
index 08bed3d..a17bd21 100644
--- a/sim/aarch64/simulator.h
+++ b/sim/aarch64/simulator.h
@@ -47,6 +47,10 @@ extern void         aarch64_init (sim_cpu *, uint64_t);
 
 extern void         aarch64_run (SIM_DESC);
 
+/* Call this to execute one instruction at the current PC.  */
+
+extern bfd_boolean  aarch64_step (sim_cpu *);
+
 extern const char * aarch64_get_func (uint64_t);
 extern uint64_t     aarch64_get_sym_value (const char *);
 extern void         aarch64_init_LIT_table (void);