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Re: [PATCH] Fix the glibc profiling issue on arm-unknown-linux-gnueabi.


Hi Joseph,

This time I have created the patch with the following sources
glibc-2.13 and glibc-ports 2.13

I have tested the profiling part on ARMv7a (Beagle Board) and have
even verified the
debug-dump.

> Thanks, this patch is a lot closer to being ready to go in.
>
>>  /* If compiled for profiling, call `mcount' at the start of each function.  */
>>  #ifdef PROF
>> +/* Call __gnu_mcount_nc if GCC > 4.4 and abi = EABI */
>> +#if __GNUC_PREREQ(4,4) && defined(__ARM_EABI__)
>> +#define CALL_MCOUNT \
>> +  str  lr,[sp, #-4]!; \
>> +  cfi_adjust_cfa_offset (4); \
>> +  cfi_rel_offset (lr, 0); \
>> +  bl PLTJMP(mcount);
>
> I think you need
>
>  cfi_adjust_cfa_offset (-4)
>  cfi_restore (lr)
>
> here, since from the caller's perspective the "bl PLTJMP(mcount)"
> instruction (calling __gnu_mcount_nc via the mcount macro you define
> later) acts by popping lr.

I have added the cfi assembler directives as per your comment.

{{{
--- a/glibc-ports-2.13/sysdeps/arm/sysdep.h     2011-01-26
02:30:16.000000000 +0530
+++ b/glibc-ports-2.13/sysdeps/arm/sysdep.h     2011-02-15
15:55:07.000000000 +0530
@@ -18,6 +18,7 @@
    02111-1307 USA.  */

 #include <sysdeps/generic/sysdep.h>
+#include <features.h>

 #if (!defined (__ARM_ARCH_2__) && !defined (__ARM_ARCH_3__) \
      && !defined (__ARM_ARCH_3M__) && !defined (__ARM_ARCH_4__))
@@ -92,6 +93,16 @@

 /* If compiled for profiling, call `mcount' at the start of each function.  */
 #ifdef PROF
+/* Call __gnu_mcount_nc if GCC > 4.4 and abi = EABI */
+#if __GNUC_PREREQ(4,4) && defined(__ARM_EABI__)
+#define CALL_MCOUNT \
+  str  lr,[sp, #-4]!; \
+  cfi_adjust_cfa_offset (4); \
+  cfi_rel_offset (lr, 0); \
+  bl PLTJMP(mcount); \
+  cfi_adjust_cfa_offset (-4); \
+  cfi_restore (lr)
+#else /* else call _mcount */
 #define CALL_MCOUNT \
   str  lr,[sp, #-4]!; \
   cfi_adjust_cfa_offset (4); \
@@ -100,6 +111,7 @@
   ldr lr, [sp], #4; \
   cfi_adjust_cfa_offset (-4); \
   cfi_restore (lr)
+#endif
 #else
 #define CALL_MCOUNT            /* Do nothing.  */
 #endif
@@ -109,8 +121,12 @@
    on this system, the asm identifier `syscall_error' intrudes on the
    C name space.  Make sure we use an innocuous name.  */
 #define        syscall_error   __syscall_error
+#if __GNUC_PREREQ(4,4) && defined(__ARM_EABI__)
+#define mcount         __gnu_mcount_nc
+#else
 #define mcount         _mcount
 #endif
+#endif

 #if defined(__ARM_EABI__)
 /* Tag_ABI_align8_preserved: This code preserves 8-byte
}}}

Thanks for your valuable inputs.

Regards,
Manjunath S Matti
Sony India Software Centre.


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