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From: "cel at us dot ibm.com" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Subject: [Bug gdb/29927] New: reverse-finish requires two reverse next
 instructions to reach previous source line
Date: Wed, 21 Dec 2022 16:56:05 +0000
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X-Bugzilla-Product: gdb
X-Bugzilla-Component: gdb
X-Bugzilla-Version: HEAD
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D29927

            Bug ID: 29927
           Summary: reverse-finish requires two reverse next instructions
                    to reach previous source line
           Product: gdb
           Version: HEAD
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdb
          Assignee: unassigned at sourceware dot org
          Reporter: cel at us dot ibm.com
  Target Milestone: ---

Currently on X86, when executing the finish command in reverse, gdb does a
single step from the first instruction in the callee to get back to the
caller.  GDB stops on the last instruction in the source code line where
the call was made.  When stopped at the last instruction of the source code
line, a reverse next or step command will stop at the first instruction
of the same source code line thus requiring two step/next commands to
reach the previous source code line.  It should only require one step/next
command to reach the previous source code line.

By contrast, a reverse next or step command from the first line in a
function stops at the first instruction in the source code line where the
call was made.

The same behavior was observed on PowerPC.

Steps to reproduce:

gdb ./foo

execute into a function call
reverse-finish         -takes you to the caller
reverse-next           -gdb is still a the caller source line
reverse-next           -gdb moves back to the previous source line.

FYI, I have a patch to fix the issue.  Will post patch shortly.

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