[committed] Don't pass -m32 to libcc1 on arm-linux

[committed] Don't pass -m32 to libcc1 on arm-linux

[Yao Qi]

When I run gdb.compile/ tests on arm-linux, I get the following fails,

(gdb) compile code -- ;^M
arm-none-linux-gnueabihf-gcc: error: unrecognized command line option '-m32'; did you mean '-mbe32'?^M
Compilation failed.^M
(gdb) compile code (void) param^M
arm-none-linux-gnueabihf-gcc: error: unrecognized command line option '-m32'; did you mean '-mbe32'?^M
Compilation failed.^M
(gdb) FAIL: gdb.compile/compile-ops.exp: compile code (void) param

This patch fixes it by implementing gcc_target_options gdbarch method
for arm-linux to override option "-m32".

gdb:

2018-01-19  Yao Qi  <yao.qi@linaro.org>

	* arm-linux-tdep.c (arm_linux_gcc_target_options): New function.
	(arm_linux_init_abi): Install it.
---
 gdb/ChangeLog        |  5 +++++
 gdb/arm-linux-tdep.c | 11 +++++++++++
 2 files changed, 16 insertions(+)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 6709f44..53fde81 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2018-01-19  Yao Qi  <yao.qi@linaro.org>
 
+	* arm-linux-tdep.c (arm_linux_gcc_target_options): New function.
+	(arm_linux_init_abi): Install it.
+
+2018-01-19  Yao Qi  <yao.qi@linaro.org>
+
 	* osabi.c (gdb_osabi_names): Extend the regexp for
 	arm-linux-gnueabihf.
 
diff --git a/gdb/arm-linux-tdep.c b/gdb/arm-linux-tdep.c
index d1262cc..e8f8c4e 100644
--- a/gdb/arm-linux-tdep.c
+++ b/gdb/arm-linux-tdep.c
@@ -1712,6 +1712,15 @@ arm_linux_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
   return find_solib_trampoline_target (frame, pc);
 }
 
+/* Implement the gcc_target_options gdbarch method.  */
+
+static char *
+arm_linux_gcc_target_options (struct gdbarch *gdbarch)
+{
+  /* GCC doesn't know "-m32".  */
+  return NULL;
+}
+
 static void
 arm_linux_init_abi (struct gdbarch_info info,
 		    struct gdbarch *gdbarch)
@@ -1992,6 +2001,8 @@ arm_linux_init_abi (struct gdbarch_info info,
   arm_linux_record_tdep.arg5 = ARM_A1_REGNUM + 4;
   arm_linux_record_tdep.arg6 = ARM_A1_REGNUM + 5;
   arm_linux_record_tdep.arg7 = ARM_A1_REGNUM + 6;
+
+  set_gdbarch_gcc_target_options (gdbarch, arm_linux_gcc_target_options);
 }
 
 void
-- 
1.9.1

Re: [committed] Don't pass -m32 to libcc1 on arm-linux

[Andreas Schwab]

On Jan 19 2018, Yao Qi <qiyaoltc@gmail.com> wrote:

> This patch fixes it by implementing gcc_target_options gdbarch method
> for arm-linux to override option "-m32".

Why is that not the default?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [committed] Don't pass -m32 to libcc1 on arm-linux

[Pedro Alves]

On 01/19/2018 04:24 PM, Andreas Schwab wrote:
> On Jan 19 2018, Yao Qi <qiyaoltc@gmail.com> wrote:
> 
>> This patch fixes it by implementing gcc_target_options gdbarch method
>> for arm-linux to override option "-m32".
> 
> Why is that not the default?
I think for really no good reason other than the coincidence that
the first couple ports that implemented this hook could share the
same set of "-m" options.

I agree that changing the default would be better.  "-m" options are,
by design, machine-specific.

Thanks,
Pedro Alves

Re: [committed] Don't pass -m32 to libcc1 on arm-linux

[Yao Qi]

On Fri, Jan 19, 2018 at 4:34 PM, Pedro Alves <palves@redhat.com> wrote:
> On 01/19/2018 04:24 PM, Andreas Schwab wrote:
>> On Jan 19 2018, Yao Qi <qiyaoltc@gmail.com> wrote:
>>
>>> This patch fixes it by implementing gcc_target_options gdbarch method
>>> for arm-linux to override option "-m32".
>>
>> Why is that not the default?
> I think for really no good reason other than the coincidence that
> the first couple ports that implemented this hook could share the
> same set of "-m" options.

The compile project was started for x86, so it had x86 options in
default.

char *
default_gcc_target_options (struct gdbarch *gdbarch)
{
  return xstrprintf ("-m%d%s", gdbarch_ptr_bit (gdbarch),
    gdbarch_ptr_bit (gdbarch) == 64 ? " -mcmodel=large" : "");
}

which is not correct for other arches.  What is more, we have
no way to disable "compile" feature even it is not support on
some arches.  If libcc1.so can be loaded in GDB, GDB thinks
everything is OK, and use it unconditionally for "compile"
feature.

-- 
Yao (齐尧)