[Bug gdb/26523] New: advance/until to inline frames

[Bug gdb/26523] New: advance/until to inline frames

[palves at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26523

            Bug ID: 26523
           Summary: advance/until to inline frames
           Product: gdb
           Version: unknown
            Status: NEW
          Severity: normal
          Priority: P2
         Component: gdb
          Assignee: unassigned at sourceware dot org
          Reporter: palves at redhat dot com
  Target Milestone: ---

If you do "tbreak LINENO; c" to advance to an inlined function, GDB
presents the stop at the inline frame instead of at the non-artificial
stack frame:

 (gdb) list 21
 18      static inline __attribute__ ((always_inline)) int
 19      inline_func (int i)
 20      {
 21        return i + 1;
 22      }

 (gdb) tbreak 21
 Temporary breakpoint 3 at 0x55555555516f: advance.cc:21.
 (gdb) c
 Continuing.

 Temporary breakpoint 3, inline_func (i=0) at advance.cc:21
 21        return i + 1; /* multiple locations here */

If however, you do "advance LINENO" or "until LINENO" instead, GDB
presents the stop at the non-artificial frame:

 (gdb) advance 21
 main () at advance.cc:43
 43        i = inline_func (i);
 (gdb)

"advance" and "until" should really behave like user breakpoints here, since
their location is also user-specified.

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[Bug gdb/26523] advance/until to inline frames

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26523

--- Comment #1 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Pedro Alves <palves@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b2b38aa45ba2eb2e7e4c70689d679c4c467eda73

commit b2b38aa45ba2eb2e7e4c70689d679c4c467eda73
Author: Pedro Alves <pedro@palves.net>
Date:   Thu Aug 27 21:03:53 2020 +0100

    Fix advance/until and inline frames (PR gdb/26523)

    If you do "tbreak LINENO; c" to advance to an inlined function, GDB
    presents the stop at the inline frame instead of at the non-artificial
    stack frame:

     (gdb) list 21
     18      static inline __attribute__ ((always_inline)) int
     19      inline_func (int i)
     20      {
     21        return i + 1;
     22      }

     (gdb) tbreak 21
     Temporary breakpoint 3 at 0x55555555516f: advance.cc:21.
     (gdb) c
     Continuing.

     Temporary breakpoint 3, inline_func (i=0) at advance.cc:21
     21        return i + 1;

    The logic for this is in stopped_by_user_bp_inline_frame:

     /* Loop over the stop chain and determine if execution stopped in an
        inlined frame because of a breakpoint with a user-specified
        location set at FRAME_BLOCK.  */

     static bool
     stopped_by_user_bp_inline_frame (const block *frame_block, bpstat
stop_chain)

    If however, you do "advance LINENO" or "until LINENO" instead, GDB
    presents the stop at the non-artificial frame:

     (gdb) advance 21
     main () at advance.cc:43
     43        i = inline_func (i);
     (gdb)

    "advance" and "until" should really behave like user breakpoints here,
    since their location is also user-specified.  As the comment in
    gdb.base/advance.exp says, "advance <location>" is really just
    syntactic sugar for "tbreak <location>; continue".

    Fix this by making stopped_by_user_bp_inline_frame also consider
    advance/until breakpoints.

    A testcase covering this will be included in the next patch.

    gdb/ChangeLog:

            PR gdb/26523
            * inline-frame.c (stopped_by_user_bp_inline_frame): Also consider
            bp_until breakpoints user-specified locations.  Update intro
            comment.

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[Bug gdb/26523] advance/until to inline frames

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26523

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Pedro Alves <palves@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=df63178325a5705a609bff94a349162bbb839895

commit df63178325a5705a609bff94a349162bbb839895
Author: Pedro Alves <pedro@palves.net>
Date:   Thu Aug 27 21:03:53 2020 +0100

    Fix advance/until and multiple locations (PR gdb/26524)

    If you do "advance LINESPEC", and LINESPEC expands to more than one
    location, GDB just errors out:

       if (sals.size () != 1)
         error (_("Couldn't get information on specified line."));

    For example, advancing to a line in an inlined function, inlined three
    times:

     (gdb) b 21
     Breakpoint 1 at 0x55555555516f: advance.cc:21. (3 locations)
     (gdb) info breakpoints
     Num     Type           Disp Enb Address            What
     1       breakpoint     keep y   <MULTIPLE>
     1.1                         y   0x000055555555516f in inline_func at
advance.cc:21
     1.2                         y   0x000055555555517e in inline_func at
advance.cc:21
     1.3                         y   0x000055555555518d in inline_func at
advance.cc:21
     (gdb) advance 21
     Couldn't get information on specified line.
     (gdb)

    Similar issue with the "until" command, as it shares the
    implementation with "advance".

    Since, as the comment in gdb.base/advance.exp says, "advance <location>"
    is really just syntactic sugar for "tbreak <location>;continue",
    fix this by making GDB insert a breakpoint at all the resolved
    locations.

    A new testcase is included, which exercises both "advance" and
    "until", in two different cases expanding to multiple locations:

      - inlined functions
      - C++ overloads

    This also exercises the inline frames issue fixed by the previous
    patch.

    gdb/ChangeLog:

            PR gdb/26524
            * breakpoint.c (until_break_fsm) <location_breakpoint,
            caller_breakpoint>: Delete fields.
            <breakpoints>: New field.
            <until_break_fsm>: Adjust to save a breakpoint vector instead of
            two individual breakpoints.
            (until_break_fsm::should_stop): Loop over breakpoints in the
            breakpoint vector.
            (until_break_fsm::clean_up): Adjust to clear the breakpoints
            vector.
            (until_break_command): Handle location expanding into multiple
            sals.

    gdb/testsuite/ChangeLog:

            PR gdb/26523
            PR gdb/26524
            * gdb.base/advance-until-multiple-locations.cc: New.
            * gdb.base/advance-until-multiple-locations.exp: New.

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[Bug gdb/26523] advance/until to inline frames

[palves at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26523

Pedro Alves <palves at redhat dot com> changed:

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

--- Comment #3 from Pedro Alves <palves at redhat dot com> ---
Fix merged.

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[Bug gdb/26523] advance/until to inline frames

[palves at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26523

--- Comment #4 from Pedro Alves <palves at redhat dot com> ---
Fix merged.

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