[Bug sanitizer/55488] New: Implement cold calls in tsan run-time

[Bug sanitizer/55488] New: Implement cold calls in tsan run-time

[konstantin.s.serebryany at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55488

             Bug #: 55488
           Summary: Implement cold calls in tsan run-time
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: konstantin.s.serebryany@gmail.com
                CC: dodji@gcc.gnu.org, dvyukov@gcc.gnu.org,
                    jakub@gcc.gnu.org, kcc@gcc.gnu.org, wmi@gcc.gnu.org


The hottest functions in tsan run-time make two cold calls: __tsan_report_race
and __tsan_trace_switch

If these calls are implemented via regular calling convention,
they ruin the performance since the compiler creates too many spills.
So, we've manually implemented a cold-call calling convention using a separate
assembly file, libsanitizer/tsan/tsan_rtl_amd64.S

Currently, this hack is disabled in GCC causing the tsan run-time to be slower
than it could be: 

libsanitizer/tsan/tsan_rtl.h: 

#if 0 && TSAN_DEBUG == 0
...
#define HACKY_CALL(f) \


We need to enable building/linking the file libsanitizer/tsan/tsan_rtl_amd64.S
and enable the HACKY_CALL in libsanitizer/tsan/tsan_rtl.h. This will eliminate
the only difference left between the gcc version and upstream. 

Or maybe gcc has another way to implement a cold call?

[Bug sanitizer/55488] Implement cold calls in tsan run-time

[wmi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55488

--- Comment #1 from wmi at gcc dot gnu.org 2013-01-10 17:57:40 UTC ---
Author: wmi
Date: Thu Jan 10 17:57:34 2013
New Revision: 195092

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=195092
Log:
2013-01-10  Wei Mi  <wmi@google.com>

libsanitizer/
        PR sanitizer/55488
        * tsan/Makefile.am: Add tsan_rtl_amd64.S.
        * tsan/Makefile.in: Regenerated.
        * tsan/tsan_rtl.h: Enable HACKY_CALL.

Modified:
    trunk/libsanitizer/ChangeLog
    trunk/libsanitizer/tsan/Makefile.am
    trunk/libsanitizer/tsan/Makefile.in
    trunk/libsanitizer/tsan/tsan_rtl.h

[Bug sanitizer/55488] Implement cold calls in tsan run-time

[dvyukov at google dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55488

Dmitry Vyukov <dvyukov at google dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dvyukov at google dot com

--- Comment #2 from Dmitry Vyukov <dvyukov at google dot com> 2013-01-11 19:52:55 UTC ---
Great, thanks!
I guess we need to close this bug now.

[Bug sanitizer/55488] Implement cold calls in tsan run-time

[kcc at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55488

Kostya Serebryany <kcc at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED

--- Comment #3 from Kostya Serebryany <kcc at gcc dot gnu.org> 2013-01-14 13:20:01 UTC ---
thanks! I confirmed the fix.