This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [RFC] libgcov.c re-factoring and offline profile-tool


gcov_rewrite function is only needed (and defined) with IN_LIBGCOV.
Should it be moved from common file gcov-io.c to libgcov.c?


David

On Thu, Dec 12, 2013 at 12:11 PM, Teresa Johnson <tejohnson@google.com> wrote:
> On Wed, Dec 11, 2013 at 10:05 PM, Teresa Johnson <tejohnson@google.com> wrote:
>> On Fri, Dec 6, 2013 at 6:23 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>>>> Hi, all
>>>>
>>>> This is the new patch for gcov-tool (previously profile-tool).
>>>>
>>>> Honza: can you comment on the new merge interface? David posted some
>>>> comments in an earlier email and we want to know what's your opinion.
>>>>
>>>> Test patch has been tested with boostrap, regresssion,
>>>> profiledbootstrap and SPEC2006.
>>>>
>>>> Noticeable changes from the earlier version:
>>>>
>>>> 1. create a new file libgcov.h and move libgcov-*.h headers to libgcov.h
>>>> So we can included multiple libgcov-*.c without adding new macros.
>>>>
>>>> 2. split libgcov.h specific code in gcvo-io.h to libcc/libgcov.h
>>>> Avoid multiple-page of code under IN_LIBGCOV macro -- this
>>>> improves the readability.
>>>>
>>>> 3. make gcov_var static, and move the definition from gcov-io.h to
>>>> gcov-io.c. Also
>>>>    move some static functions accessing gcov_var to gcvo-io.c
>>>> Current code rely on GCOV_LINKAGE tricks to avoid multi-definition. I don't see
>>>> a reason that gcov_var needs to exposed as a global.
>>>>
>>>> 4. expose gcov_write_strings() and gcov_sync() to gcov_tool usage
>>>>
>>>> 5. rename profile-tool to gcov-tool per Honza's suggestion.
>>>>
>>>> Thanks,
>>>
>>> Hi,
>>> I did not read in deatil the gcov-tool source itself, but lets first make the interface changes
>>> needed.
>>>
>>>> 2013-11-18  Rong Xu  <xur@google.com>
>>>>
>>>>       * gcc/gcov-io.c (gcov_var): Moved from gcov-io.h and make it static.
>>>>       (gcov_position): Move from gcov-io.h
>>>>       (gcov_is_error): Ditto.
>>>>       (gcov_rewrite): Ditto.
>>>>       * gcc/gcov-io.h: Re-factoring. Move gcov_var to gcov-io.h and
>>>>         move the libgcov only part of libgcc/libgcov.h.
>>>>       * libgcc/libgcov.h: New common header files for libgcov-*.h
>>>>       * libgcc/Makefile.in: Add dependence to libgcov.h
>>>>       * libgcc/libgcov-profiler.c: Use libgcov.h
>>>>       * libgcc/libgcov-driver.c: Ditto.
>>>>       * libgcc/libgcov-interface.c: Ditto.
>>>>       * libgcc/libgcov-driver-system.c (allocate_filename_struct): use
>>>>       xmalloc instread of malloc.
>>>>       * libgcc/libgcov-merge.c (void __gcov_merge_delta): Add more
>>>>       parameters to merge function.
>>>>       (__gcov_merge_add): Ditto.
>>>>       (__gcov_merge_ior): Ditto.
>>>>       (__gcov_merge_time_profile): Ditto.
>>>>       (__gcov_merge_single): Ditto.
>>>>       (__gcov_merge_delta): Ditto.
>>>>       * libgcc/libgcov-tool.c (void gcov_tool_set_verbose): New for
>>>>       gcov-tool support.
>>>>       (set_fn_ctrs): Ditto.
>>>>       (tag_function): Ditto.
>>>>       (tag_blocks): Ditto.
>>>>       (tag_arcs): Ditto.
>>>>       (tag_lines): Ditto.
>>>>       (tag_counters): Ditto.
>>>>       (tag_summary): Ditto.
>>>>       (read_gcda_finalize): Ditto.
>>>>       (read_gcda_file): Ditto.
>>>>       (ftw_read_file): Ditto.
>>>>       (read_profile_dir_init) Ditto.:
>>>>       (gcov_read_profile_dir): Ditto.
>>>>       (gcov_merge): Ditto.
>>>>       (find_match_gcov_inf Ditto.o):
>>>>       (gcov_profile_merge): Ditto.
>>>>       (__gcov_scale_add): Ditto.
>>>>       (__gcov_scale_ior): Ditto.
>>>>       (__gcov_scale_delta): Ditto.
>>>>       (__gcov_scale_single): Ditto.
>>>>       (gcov_profile_scale): Ditto.
>>>>       (gcov_profile_normalize): Ditto.
>>>>       (__gcov_scale2_add): Ditto.
>>>>       (__gcov_scale2_ior): Ditto.
>>>>       (__gcov_scale2_delta): Ditto.
>>>>       (__gcov_scale2_single): Ditto.
>>>>       (gcov_profile_scale2): Ditto.
>>>>       * gcc/gcov-tool.c (unlink_file): Gcov-tool driver support.
>>>>       (unlink_dir): Ditto.
>>>>       (profile_merge): Ditto.
>>>>       (print_merge_usage_message): Ditto.
>>>>       (merge_usage): Ditto.
>>>>       (do_merge): Ditto.
>>>>       (profile_rewrite2): Ditto.
>>>>       (profile_rewrite): Ditto.
>>>>       (print_rewrite_usage_message): Ditto.
>>>>       (rewrite_usage): Ditto.
>>>>       (do_rewrite): Ditto.
>>>>       (print_usage): Ditto.
>>>>       (print_version): Ditto.
>>>>       (process_args): Ditto.
>>>>       (main): Ditto.
>>>>       * gcc/Makefile.in: Build and install gcov-tool.
>>>
>>>> Index: gcc/gcov-io.c
>>>> ===================================================================
>>>> --- gcc/gcov-io.c     (revision 204895)
>>>> +++ gcc/gcov-io.c     (working copy)
>>>> @@ -36,6 +36,37 @@ static const gcov_unsigned_t *gcov_read_words (uns
>>>>  static void gcov_allocate (unsigned);
>>>>  #endif
>>>>
>>>> +/* Moved for gcov-io.h and make it static.  */
>>>> +static struct gcov_var gcov_var;
>>>
>>> This is more an changelog message than a comment in source file.
>>> Just describe what gcov_var is.
>>
>> I changed this so gcov_var is no longer static, but global as before.
>>
>>>
>>> Do you know how the size of libgcov changed with your patch?
>>> Quick check of current mainline on compiling empty main gives:
>>>
>>> jh@gcc10:~/trunk/build/gcc$ cat t.c
>>> main()
>>> {
>>> }
>>> jh@gcc10:~/trunk/build/gcc$ ./xgcc -B ./ -O2 -fprofile-generate -o a.out-new --static t.c
>>> jh@gcc10:~/trunk/build/gcc$ gcc -O2 -fprofile-generate -o a.out-old --static t.c
>>> jh@gcc10:~/trunk/build/gcc$ size a.out-old
>>>    text    data     bss     dec     hex filename
>>>  608141    3560   16728  628429   996cd a.out-old
>>> jh@gcc10:~/trunk/build/gcc$ size a.out-new
>>>    text    data     bss     dec     hex filename
>>>  612621    3688   22880  639189   9c0d5 a.out-new
>>>
>>> Without profiling I get:
>>> jh@gcc10:~/trunk/build/gcc$ size a.out-new-no
>>> jh@gcc10:~/trunk/build/gcc$ size a.out-old-no
>>>    text    data     bss     dec     hex filename
>>>  599719    3448   12568  615735   96537 a.out-old-no
>>>    text    data     bss     dec     hex filename
>>>  600247    3448   12568  616263   96747 a.out-new-no
>>>
>>> Quite big for empty program, but mostly glibc fault, I suppose
>>> (that won't be an issue for embedded platforms). But anyway
>>> we increased text size overhead from 8k to 12k, BSS size
>>> overhead from 4k to 10k and data by another 1k.
>>>
>>>    text    data     bss     dec     hex filename
>>>     126       0       0     126      7e _gcov_merge_add.o (ex libgcov.a)
>>>     251       0       0     251      fb _gcov_merge_single.o (ex libgcov.a)
>>>     242       0       0     242      f2 _gcov_merge_delta.o (ex libgcov.a)
>>>     126       0       0     126      7e _gcov_merge_ior.o (ex libgcov.a)
>>>     156       0       0     156      9c _gcov_merge_time_profile.o (ex libgcov.a)
>>>      89       0       0      89      59 _gcov_interval_profiler.o (ex libgcov.a)
>>>      69       0       0      69      45 _gcov_pow2_profiler.o (ex libgcov.a)
>>>     115       0       0     115      73 _gcov_one_value_profiler.o (ex libgcov.a)
>>>     122       0       0     122      7a _gcov_indirect_call_profiler.o (ex libgcov.a)
>>>      57       0       0      57      39 _gcov_average_profiler.o (ex libgcov.a)
>>>      52       0       0      52      34 _gcov_ior_profiler.o (ex libgcov.a)
>>>     178       0      16     194      c2 _gcov_indirect_call_profiler_v2.o (ex libgcov.a)
>>>      77       0       8      85      55 _gcov_time_profiler.o (ex libgcov.a)
>>>     126       0      40     166      a6 _gcov_flush.o (ex libgcov.a)
>>>     101       0       0     101      65 _gcov_fork.o (ex libgcov.a)
>>>     471       0       0     471     1d7 _gcov_execl.o (ex libgcov.a)
>>>     471       0       0     471     1d7 _gcov_execlp.o (ex libgcov.a)
>>>     524       0       0     524     20c _gcov_execle.o (ex libgcov.a)
>>>      98       0       0      98      62 _gcov_execv.o (ex libgcov.a)
>>>      98       0       0      98      62 _gcov_execvp.o (ex libgcov.a)
>>>     108       0       0     108      6c _gcov_execve.o (ex libgcov.a)
>>>      66       0       0      66      42 _gcov_reset.o (ex libgcov.a)
>>>      66       0       0      66      42 _gcov_dump.o (ex libgcov.a)
>>>    9505       0    6144   15649    3d21 _gcov.o (ex libgcov.a)
>>>
>>> I think we definitely need to move those 6k of bss space out.  I think those are new
>>> static vars you introduced that I think are unsafe anyway because multiple streaming
>>> may run at once in threaded program where locking mechanizm fails.
>>> (it will probably do other bad things, but definitely we do not want to
>>> conflict on things like filename to write into).
>>>
>>> Compared to my system gcov:
>>>    text    data     bss     dec     hex filename
>>>    9765       0      64    9829    2665 _gcov.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     125       0       0     125      7d _gcov_merge_add.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     251       0       0     251      fb _gcov_merge_single.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     242       0       0     242      f2 _gcov_merge_delta.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     101       0       0     101      65 _gcov_fork.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     471       0       0     471     1d7 _gcov_execl.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     471       0       0     471     1d7 _gcov_execlp.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     524       0       0     524     20c _gcov_execle.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      98       0       0      98      62 _gcov_execv.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      98       0       0      98      62 _gcov_execvp.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     108       0       0     108      6c _gcov_execve.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      72       0       0      72      48 _gcov_reset.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      72       0       0      72      48 _gcov_dump.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      89       0       0      89      59 _gcov_interval_profiler.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      69       0       0      69      45 _gcov_pow2_profiler.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     115       0       0     115      73 _gcov_one_value_profiler.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     122       0       0     122      7a _gcov_indirect_call_profiler.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      57       0       0      57      39 _gcov_average_profiler.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>      52       0       0      52      34 _gcov_ior_profiler.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>     125       0       0     125      7d _gcov_merge_ior.o (ex ./lib64/gcc/x86_64-suse-linux/4.8/libgcov.a)
>>>
>>>> Index: gcc/gcov-io.h
>>>> ===================================================================
>>>> --- gcc/gcov-io.h     (revision 204895)
>>>> +++ gcc/gcov-io.h     (working copy)
>>>> @@ -164,51 +164,7 @@ see the files COPYING3 and COPYING.RUNTIME respect
>>>>  #ifndef GCC_GCOV_IO_H
>>>>  #define GCC_GCOV_IO_H
>>>>
>>>> -#if IN_LIBGCOV
>>>> -/* About the target */
>>>> -
>>>> -#if BITS_PER_UNIT == 8
>>>> -typedef unsigned gcov_unsigned_t __attribute__ ((mode (SI)));
>>>> -typedef unsigned gcov_position_t __attribute__ ((mode (SI)));
>>>> -#if LONG_LONG_TYPE_SIZE > 32
>>>> -typedef signed gcov_type __attribute__ ((mode (DI)));
>>>> -typedef unsigned gcov_type_unsigned __attribute__ ((mode (DI)));
>>>> -#else
>>>> -typedef signed gcov_type __attribute__ ((mode (SI)));
>>>> -typedef unsigned gcov_type_unsigned __attribute__ ((mode (SI)));
>>>> -#endif
>>>> -#else
>>>> -#if BITS_PER_UNIT == 16
>>>> -typedef unsigned gcov_unsigned_t __attribute__ ((mode (HI)));
>>>> -typedef unsigned gcov_position_t __attribute__ ((mode (HI)));
>>>> -#if LONG_LONG_TYPE_SIZE > 32
>>>> -typedef signed gcov_type __attribute__ ((mode (SI)));
>>>> -typedef unsigned gcov_type_unsigned __attribute__ ((mode (SI)));
>>>> -#else
>>>> -typedef signed gcov_type __attribute__ ((mode (HI)));
>>>> -typedef unsigned gcov_type_unsigned __attribute__ ((mode (HI)));
>>>> -#endif
>>>> -#else
>>>> -typedef unsigned gcov_unsigned_t __attribute__ ((mode (QI)));
>>>> -typedef unsigned gcov_position_t __attribute__ ((mode (QI)));
>>>> -#if LONG_LONG_TYPE_SIZE > 32
>>>> -typedef signed gcov_type __attribute__ ((mode (HI)));
>>>> -typedef unsigned gcov_type_unsigned __attribute__ ((mode (HI)));
>>>> -#else
>>>> -typedef signed gcov_type __attribute__ ((mode (QI)));
>>>> -typedef unsigned gcov_type_unsigned __attribute__ ((mode (QI)));
>>>> -#endif
>>>> -#endif
>>>> -#endif
>>>
>>> So this part basically moves libgcov specific bits into libgcov.h? That OK fine by
>>> itself.
>>>> Index: libgcc/libgcov-profiler.c
>>>> ===================================================================
>>>> --- libgcc/libgcov-profiler.c (revision 204895)
>>>> +++ libgcc/libgcov-profiler.c (working copy)
>>>> @@ -23,15 +23,8 @@ a copy of the GCC Runtime Library Exception along
>>>>  see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
>>>>  <http://www.gnu.org/licenses/>.  */
>>>>
>>>> -#include "tconfig.h"
>>>> -#include "tsystem.h"
>>>> -#include "coretypes.h"
>>>> -#include "tm.h"
>>>> -#include "libgcc_tm.h"
>>>> -
>>>> +#include "libgcov.h"
>>>>  #if !defined(inhibit_libc)
>>>> -#define IN_LIBGCOV 1
>>>> -#include "gcov-io.h"
>>>
>>> I did not pay that much attention into the current include file changes, but wasn't
>>> idea to avoid #include file to include random other #includes?
>>> So perhaps the first block of includes should stay, followed by libgcov.h and gcov-io.h
>>> last?
>>
>> I'm not sure I understand the issue here? The patch basically moves
>> the same includes into libgcov.h, and includes that instead. I see
>> many other header files in gcc that include other headers.
>>
>>>> @@ -325,6 +311,9 @@ static struct gcov_summary all_prg;
>>>>  #endif
>>>>  /* crc32 for this program.  */
>>>>  static gcov_unsigned_t crc32;
>>>> +/* Use this summary checksum rather the computed one if the value is
>>>> + *    non-zero.  */
>>>> +static gcov_unsigned_t saved_summary_checksum;
>>>
>>> Why do you need to save the checksum? Won't it reset summary back with multiple streaming?
>>
>> This has been removed.
>>
>>>
>>> I would really like to avoid introducing those static vars that are used exclusively
>>> by gcov_exit.  What about putting them into an gcov_context structure that
>>> is passed around the functions that was broken out?
>>>> Index: libgcc/libgcov-merge.c
>>>> ===================================================================
>>>> --- libgcc/libgcov-merge.c    (revision 204895)
>>>> +++ libgcc/libgcov-merge.c    (working copy)
>>>> @@ -23,107 +23,150 @@ a copy of the GCC Runtime Library Exception along
>>>>  see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
>>>>  <http://www.gnu.org/licenses/>.  */
>>>>
>>>> -#include "tconfig.h"
>>>> -#include "tsystem.h"
>>>> -#include "coretypes.h"
>>>> -#include "tm.h"
>>>> -#include "libgcc_tm.h"
>>>> +#include "libgcov.h"
>>>>
>>>> -#if defined(inhibit_libc)
>>>> -#define IN_LIBGCOV (-1)
>>>> -#else
>>>> -#define IN_LIBGCOV 1
>>>> +#include "gcov-io-libgcov.h"
>>>>  #endif
>>>>
>>>> -#include "gcov-io.h"
>>>> -
>>>>  #if defined(inhibit_libc)
>>>>  /* If libc and its header files are not available, provide dummy functions.  */
>>>>
>>>>  #ifdef L_gcov_merge_add
>>>>  void __gcov_merge_add (gcov_type *counters  __attribute__ ((unused)),
>>>> -                       unsigned n_counters __attribute__ ((unused))) {}
>>>> +                       unsigned n_counters __attribute__ ((unused)),
>>>> +                       unsigned gcov_type *src __attribute__ ((unused)),
>>>> +                       unsigned w __attribute__ ((unused))) {}
>>>>  #endif
>>>>
>>>>  #ifdef L_gcov_merge_single
>>>>  void __gcov_merge_single (gcov_type *counters  __attribute__ ((unused)),
>>>> -                          unsigned n_counters __attribute__ ((unused))) {}
>>>> +                          unsigned n_counters __attribute__ ((unused)),
>>>> +                          unsigned gcov_type *src __attribute__ ((unused)),
>>>> +                          unsigned w __attribute__ ((unused))) {}
>>>>  #endif
>>>>
>>>>  #ifdef L_gcov_merge_delta
>>>>  void __gcov_merge_delta (gcov_type *counters  __attribute__ ((unused)),
>>>> -                         unsigned n_counters __attribute__ ((unused))) {}
>>>> +                         unsigned n_counters __attribute__ ((unused)),
>>>> +                         unsigned gcov_type *src __attribute__ ((unused)),
>>>> +                         unsigned w __attribute__ ((unused))) {}
>>>>  #endif
>>>>
>>>>  #else
>>>>
>>>>  #ifdef L_gcov_merge_add
>>>>  /* The profile merging function that just adds the counters.  It is given
>>>> -   an array COUNTERS of N_COUNTERS old counters and it reads the same number
>>>> -   of counters from the gcov file.  */
>>>> +   an array COUNTERS of N_COUNTERS old counters.
>>>> +   When SRC==NULL, it reads the same number of counters from the gcov file.
>>>> +   Otherwise, it reads from SRC array. These read values will be multiplied
>>>> +   by weight W before adding to the old counters.  */
>>>>  void
>>>> -__gcov_merge_add (gcov_type *counters, unsigned n_counters)
>>>> +__gcov_merge_add (gcov_type *counters, unsigned n_counters,
>>>> +                  gcov_type *src, unsigned w)
>>>>  {
>>>> +  int in_mem = (src != 0);
>>>> +
>>>>    for (; n_counters; counters++, n_counters--)
>>>> -    *counters += gcov_read_counter ();
>>>> +    {
>>>> +      gcov_type value;
>>>> +
>>>> +      if (in_mem)
>>>> +        value = *(src++);
>>>> +      else
>>>> +        value = gcov_read_counter ();
>>>> +
>>>> +      *counters += w * value;
>>>> +    }
>>>>  }
>>>>  #endif /* L_gcov_merge_add */
>>>>
>>>>  #ifdef L_gcov_merge_ior
>>>>  /* The profile merging function that just adds the counters.  It is given
>>>> -   an array COUNTERS of N_COUNTERS old counters and it reads the same number
>>>> -   of counters from the gcov file.  */
>>>> +   an array COUNTERS of N_COUNTERS old counters.
>>>> +   When SRC==NULL, it reads the same number of counters from the gcov file.
>>>> +   Otherwise, it reads from SRC array.  */
>>>>  void
>>>> -__gcov_merge_ior (gcov_type *counters, unsigned n_counters)
>>>> +__gcov_merge_ior (gcov_type *counters, unsigned n_counters,
>>>> +                  gcov_type *src, unsigned w __attribute__ ((unused)))
>>>
>>> So the new in-memory variants are introduced for merging tool, while libgcc use gcov_read_counter
>>> interface?
>>> Perhaps we can actually just duplicate the functions to avoid runtime to do all the scalling
>>> and in_mem tests it won't need?
>>>
>>> I would suggest going with libgcov.h changes and clenaups first, with interface changes next
>>> and the gcov-tool is probably quite obvious at the end?
>>> Do you think you can split the patch this way?
>>>
>>> Thanks and sorry for taking long to review. I should have more time again now.
>>> Honza
>>
>> The libgcov.h related changes are in the attached patch. I think it
>> addresses your concerns. Bootstrapped and tested on
>> x86-64-unknown-linux-gnu. A profiledbootstrap is in progress.
>>
>> Ok for trunk if profiledbootstrap passes?
>
> Both a profiledbootstrap and LTO profiledbootstrap pass.
>
> Teresa
>
>>
>> Thanks,
>> Teresa
>>
>>
>> --
>> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413
>
>
>
> --
> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]