[2/2,AArch64] Add more debugging output to aarch64_displaced_step_fixup

Message ID 20191230162535.21211-2-luis.machado@linaro.org
State New
Headers show
Series
  • [1/2,AArch64] Fix step-over-syscall.exp failure
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Commit Message

Luis Machado Dec. 30, 2019, 4:25 p.m.
While debugging the step-over-syscall problem, i wanted to see a bit more
debugging output to try to determine the root cause.

This patch does this.

gdb/ChangeLog:

2019-12-30  Luis Machado  <luis.machado@linaro.org>

	* aarch64-tdep.c (aarch64_displaced_step_fixup): Add more debugging
	output.

Signed-off-by: Luis Machado <luis.machado@linaro.org>

---
 gdb/aarch64-tdep.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

-- 
2.17.1

Comments

Luis Machado Dec. 30, 2019, 4:50 p.m. | #1
cc-ing Alan.

On 12/30/19 1:25 PM, Luis Machado wrote:
> While debugging the step-over-syscall problem, i wanted to see a bit more

> debugging output to try to determine the root cause.

> 

> This patch does this.

> 

> gdb/ChangeLog:

> 

> 2019-12-30  Luis Machado  <luis.machado@linaro.org>

> 

> 	* aarch64-tdep.c (aarch64_displaced_step_fixup): Add more debugging

> 	output.

> 

> Signed-off-by: Luis Machado <luis.machado@linaro.org>

> ---

>   gdb/aarch64-tdep.c | 24 +++++++++++++++++++++++-

>   1 file changed, 23 insertions(+), 1 deletion(-)

> 

> diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c

> index a639b753cd..2d6c5a4bcb 100644

> --- a/gdb/aarch64-tdep.c

> +++ b/gdb/aarch64-tdep.c

> @@ -3058,8 +3058,16 @@ aarch64_displaced_step_fixup (struct gdbarch *gdbarch,

>     /* Fetch the current PC, after the displaced execution took place.  */

>     regcache_cooked_read_unsigned (regs, AARCH64_PC_REGNUM, &pc);

>   

> +  if (debug_displaced)

> +    debug_printf ("displaced: PC after stepping: %s (was %s).\n",

> +		  paddress (gdbarch, pc), paddress (gdbarch, to));

> +

>     if (dsc->cond)

>       {

> +      if (debug_displaced)

> +	debug_printf ("displaced: [Conditional] pc_adjust before: %d\n",

> +		      dsc->pc_adjust);

> +

>         if (pc - to == 8)

>   	{

>   	  /* Condition is true.  */

> @@ -3072,8 +3080,17 @@ aarch64_displaced_step_fixup (struct gdbarch *gdbarch,

>   	}

>         else

>   	gdb_assert_not_reached ("Unexpected PC value after displaced stepping");

> +

> +      if (debug_displaced)

> +	debug_printf ("displaced: [Conditional] pc_adjust after: %d\n",

> +		      dsc->pc_adjust);

>       }

>   

> +  if (debug_displaced)

> +    debug_printf ("displaced: %s PC by %d\n",

> +		  dsc->should_adjust_pc? "adjusting" : "not adjusting",

> +		  dsc->pc_adjust);

> +

>     if (dsc->should_adjust_pc)

>       {

>   

> @@ -3082,7 +3099,12 @@ aarch64_displaced_step_fixup (struct gdbarch *gdbarch,

>   	 and the instruction after the syscall instruction.  Make sure we don't

>   	 adjust the PC when we did not really move.  */

>         if ((pc - to) == 0)

> -	dsc->pc_adjust = 0;

> +	{

> +	  if (debug_displaced)

> +	    debug_printf ("displaced: PC did not move. Discarding PC \

> +adjustment.\n");

> +	  dsc->pc_adjust = 0;

> +	}

>   

>         if (debug_displaced)

>   	{

>

Patch

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index a639b753cd..2d6c5a4bcb 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -3058,8 +3058,16 @@  aarch64_displaced_step_fixup (struct gdbarch *gdbarch,
   /* Fetch the current PC, after the displaced execution took place.  */
   regcache_cooked_read_unsigned (regs, AARCH64_PC_REGNUM, &pc);
 
+  if (debug_displaced)
+    debug_printf ("displaced: PC after stepping: %s (was %s).\n",
+		  paddress (gdbarch, pc), paddress (gdbarch, to));
+
   if (dsc->cond)
     {
+      if (debug_displaced)
+	debug_printf ("displaced: [Conditional] pc_adjust before: %d\n",
+		      dsc->pc_adjust);
+
       if (pc - to == 8)
 	{
 	  /* Condition is true.  */
@@ -3072,8 +3080,17 @@  aarch64_displaced_step_fixup (struct gdbarch *gdbarch,
 	}
       else
 	gdb_assert_not_reached ("Unexpected PC value after displaced stepping");
+
+      if (debug_displaced)
+	debug_printf ("displaced: [Conditional] pc_adjust after: %d\n",
+		      dsc->pc_adjust);
     }
 
+  if (debug_displaced)
+    debug_printf ("displaced: %s PC by %d\n",
+		  dsc->should_adjust_pc? "adjusting" : "not adjusting",
+		  dsc->pc_adjust);
+
   if (dsc->should_adjust_pc)
     {
 
@@ -3082,7 +3099,12 @@  aarch64_displaced_step_fixup (struct gdbarch *gdbarch,
 	 and the instruction after the syscall instruction.  Make sure we don't
 	 adjust the PC when we did not really move.  */
       if ((pc - to) == 0)
-	dsc->pc_adjust = 0;
+	{
+	  if (debug_displaced)
+	    debug_printf ("displaced: PC did not move. Discarding PC \
+adjustment.\n");
+	  dsc->pc_adjust = 0;
+	}
 
       if (debug_displaced)
 	{