[binutils-gdb] PowerPC: regression fix for reverse-finish command.

[binutils-gdb] PowerPC: regression fix for reverse-finish command.

[Carl Love]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=70ea5a46bd926149fb4a9c3da32c2fc14f6e83c3

commit 70ea5a46bd926149fb4a9c3da32c2fc14f6e83c3
Author: Carl Love <cel@us.ibm.com>
Date:   Mon Mar 20 16:59:33 2023 -0400

    PowerPC: regression fix for reverse-finish command.
    
    The recent commit:
    
      commit 2a8339b71f37f2d02f5b2194929c9d702ef27223
      Author: Carl Love <cel@us.ibm.com>
      Date:   Thu Mar 9 16:10:18 2023 -0500
    
       PowerPC: fix for gdb.reverse/finish-precsave.exp and gdb.reverse/finish-reverse.exp
    
       PPC64 multiple entry points, a normal entry point and an alternate entry
       point.  The alternate entry point is to setup the Table of Contents (TOC)
       register before continuing at the normal entry point.  When the TOC is
       already valid, the normal entry point is used, this is typically the case.
       The alternate entry point is typically referred to as the global entry
       point (GEP) in IBM.  The normal entry point is typically referred to as
       the local entry point (LEP).
         .....
    
    Is causing regression failures on on PowerPC platforms.  The regression
    failures are in tests:
    
      gdb.reverse/finish-precsave.exp
      gdb.btrace/tailcall.exp
      gdb.mi/mi-reverse.exp
      gdb.btrace/step.exp
      gdb.reverse/until-precsave.exp
      gdb.reverse/finish-reverse.exp
      gdb.btrace/tailcall-only.exp
    
    The issue is in gdb/infcmd.c, function finish_command.  The value of the
    two new variables ALT_ENTRY_POINT and ENTRY_POINT are being initializezed
    to SAL.PC.  However, SAL has just been declared.  The value of SAL.PC is
    zero at this point.  The intialization of ALT_ENTRY_POINT and ENTRY_POINT
    needs to be after the initialization of SAL.
    
    This patch moves the initialization of ALT_ENTRY_POINT and ENTRY_POINT
    variables to fix the regression failures.
    
    The patch has been tested on Power10 and on X86.

Diff:
---
 gdb/infcmd.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index f46461512fe..e2032d18564 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1710,8 +1710,8 @@ finish_backward (struct finish_command_fsm *sm)
   struct thread_info *tp = inferior_thread ();
   CORE_ADDR pc;
   CORE_ADDR func_addr;
-  CORE_ADDR alt_entry_point = sal.pc;
-  CORE_ADDR entry_point = alt_entry_point;
+  CORE_ADDR alt_entry_point;
+  CORE_ADDR entry_point;
   frame_info_ptr frame = get_selected_frame (nullptr);
   struct gdbarch *gdbarch = get_frame_arch (frame);
 
@@ -1721,6 +1721,8 @@ finish_backward (struct finish_command_fsm *sm)
     error (_("Cannot find bounds of current function"));
 
   sal = find_pc_line (func_addr, 0);
+  alt_entry_point = sal.pc;
+  entry_point = alt_entry_point;
 
   if (gdbarch_skip_entrypoint_p (gdbarch))
     /* Some architectures, like PowerPC use local and global entry points.