[Bug tdep/16397] New: SystemTap SDT probe support for x86 doesn't work with "triplet operands"

[Bug tdep/16397] New: SystemTap SDT probe support for x86 doesn't work with "triplet operands"

[sergiodj at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16397

            Bug ID: 16397
           Summary: SystemTap SDT probe support for x86 doesn't work with
                    "triplet operands"
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: tdep
          Assignee: sergiodj at redhat dot com
          Reporter: sergiodj at redhat dot com

The SystemTap SDT probe implementation for x86 (i*86 and x86_64) support, in
theory, what we call "triplet operands", i.e., "-8+3+1(%rbp)".  However, the
current code has a bug and doesn't support this in the right way.

I've already have a fix and a testcase for it.  This bug is mostly a "don't
forget" :-).

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[Bug tdep/16397] SystemTap SDT probe support for x86 doesn't work with "triplet operands"

[cvs-commit at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=16397

--- Comment #1 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
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https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d7b30f6729ecf47b932b17f77123663e6a21bdd6

commit d7b30f6729ecf47b932b17f77123663e6a21bdd6
Author: Sergio Durigan Junior <sergiodj@redhat.com>
Date:   Thu Feb 20 18:49:09 2014 -0300

    Fix for PR tdep/16397: SystemTap SDT probe support for x86 doesn't work
with "triplet operands"

    This is the continuation of what Joel proposed on:

    <https://sourceware.org/ml/gdb-patches/2013-12/msg00977.html>

    Now that I have already submitted and pushed the patch to split
    i386_stap_parse_special_token into two smaller functions, it is indeed
    simpler to understand this patch.

    It occurs because, on x86, triplet displacement operands are allowed
    (like "-4+8-20(%rbp)"), and the current parser for this expression is
    buggy.  It does not correctly extract the register name from the
    expression, which leads to incorrect evaluation.  The parser was also
    being very "generous" with the expression, so I included a few more
    checks to ensure that we're indeed dealing with a triplet displacement
    operand.

    This patch also includes testcases for the two different kind of
    expressions that can be encountered on x86: the triplet displacement
    (explained above) and the three-argument displacement (as in
    "(%rbx,%ebx,-8)").  The tests are obviously arch-dependent and are
    placed under gdb.arch/.

    Message-ID: <m3mwj1j12v.fsf@redhat.com>
    URL: <https://sourceware.org/ml/gdb-patches/2014-01/msg00310.html>

    gdb/
    2014-02-20  Sergio Durigan Junior  <sergiodj@redhat.com>

        PR tdep/16397
        * i386-tdep.c (i386_stap_parse_special_token_triplet): Check if a
        number comes after the + or - signs.  Adjust length of register
        name to be extracted.

    gdb/testsuite/
    2014-02-20  Sergio Durigan Junior  <sergiodj@redhat.com>

        PR tdep/16397
        * gdb.arch/amd64-stap-special-operands.exp: New file.
        * gdb.arch/amd64-stap-three-arg-disp.S: Likewise.
        * gdb.arch/amd64-stap-three-arg-disp.c: Likewise.
        * gdb.arch/amd64-stap-triplet.S: Likewise.
        * gdb.arch/amd64-stap-triplet.c: Likewise.

-----------------------------------------------------------------------

Summary of changes:
 gdb/ChangeLog                                      |    7 ++
 gdb/i386-tdep.c                                    |   11 ++-
 gdb/testsuite/ChangeLog                            |    9 ++
 .../gdb.arch/amd64-stap-special-operands.exp       |   47 +++++++++++
 gdb/testsuite/gdb.arch/amd64-stap-three-arg-disp.S |   58 +++++++++++++
 gdb/testsuite/gdb.arch/amd64-stap-three-arg-disp.c |   31 +++++++
 gdb/testsuite/gdb.arch/amd64-stap-triplet.S        |   88 ++++++++++++++++++++
 gdb/testsuite/gdb.arch/amd64-stap-triplet.c        |   31 +++++++
 8 files changed, 281 insertions(+), 1 deletions(-)
 create mode 100644 gdb/testsuite/gdb.arch/amd64-stap-special-operands.exp
 create mode 100644 gdb/testsuite/gdb.arch/amd64-stap-three-arg-disp.S
 create mode 100644 gdb/testsuite/gdb.arch/amd64-stap-three-arg-disp.c
 create mode 100644 gdb/testsuite/gdb.arch/amd64-stap-triplet.S
 create mode 100644 gdb/testsuite/gdb.arch/amd64-stap-triplet.c

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[Bug tdep/16397] SystemTap SDT probe support for x86 doesn't work with "triplet operands"

[sergiodj at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16397

Sergio Durigan Junior <sergiodj at redhat dot com> changed:

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

--- Comment #2 from Sergio Durigan Junior <sergiodj at redhat dot com> ---
Fixed.

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