Re: [PING][PATCH] Fix for prologue processing on PowerPC

[Pedro Franco de Carvalho <pedromfc@linux.vnet.ibm.com>]

Looks good to me. Just two details for the testsuite changelog,
the filenames in the entry don't match the actual filenames, and there's
a space between the "*" and the entries.

I tested the patch with ppc64le and ppc32, and it works. No regressions.

Thanks!
Pedro

Nikola Prica <nikola.prica@rt-rk.com> writes:

> Hi Pedro,
>
> Thank you for your review and patience. I'm really grateful.
>
> Can someone commit this patch?
>
> Thanks,
>
> Nikola
> From 4b32b0441739d7daa931b13029f1c8215a4b1f4e Mon Sep 17 00:00:00 2001
> From: Prica <nprica@rt-rk.com>
> Date: Thu, 11 Jan 2018 14:49:15 +0100
> Subject: [PATCH] Fix for prologue processing on PowerPc
>
> One of conditions in skip_prologue() was never visited if there was mflr
> instruction that moves the link register to a register different thant r0.
> This condition expects non shifted value of `lr_reg`. Previously offset
> of link register was never saved for registers different than r0.
>
> gdb/ChangeLog:
>
> 2018-01-27 Nikola Prica  <nikola.prica@rt-rk.com>
>
>         *rs6000-tdep.c (skip_prologue): Remove shifting for lr_reg and
>          assign shifted lr_reg to fdata->lr_register when lr_reg is set.
>
> gdb/testsuite/ChangeLog:
>
> 2018-01-27 Nikola Prica  <nikola.prica@rt-rk.com>
>
>         *gdb.arch/ppc-prologue-frame.s: New file.
>         *gdb.arch/ppc-prologue-frame.c: Likewise.
>         *gdb.arch/ppr-prologue-frame.exp: Likewise.
> ---
>  gdb/rs6000-tdep.c                                 |  4 +--
>  gdb/testsuite/gdb.arch/powerpc-prologue-frame.S   | 35 +++++++++++++++++++
>  gdb/testsuite/gdb.arch/powerpc-prologue-frame.c   | 28 ++++++++++++++++
>  gdb/testsuite/gdb.arch/powerpc-prologue-frame.exp | 41 +++++++++++++++++++++++
>  4 files changed, 106 insertions(+), 2 deletions(-)
>  create mode 100644 gdb/testsuite/gdb.arch/powerpc-prologue-frame.S
>  create mode 100644 gdb/testsuite/gdb.arch/powerpc-prologue-frame.c
>  create mode 100644 gdb/testsuite/gdb.arch/powerpc-prologue-frame.exp
>
> diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
> index e5a265d..da5182e 100644
> --- a/gdb/rs6000-tdep.c
> +++ b/gdb/rs6000-tdep.c
> @@ -1654,7 +1654,7 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
>  	     remember just the first one, but skip over additional
>  	     ones.  */
>  	  if (lr_reg == -1)
> -	    lr_reg = (op & 0x03e00000) >> 21;
> +	    lr_reg = (op & 0x03e00000);
>            if (lr_reg == 0)
>              r0_contains_arg = 0;
>  	  continue;
> @@ -2180,7 +2180,7 @@ skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, CORE_ADDR lim_pc,
>  #endif /* 0 */
>
>    if (pc == lim_pc && lr_reg >= 0)
> -    fdata->lr_register = lr_reg;
> +    fdata->lr_register = lr_reg >> 21;
>
>    fdata->offset = -fdata->offset;
>    return last_prologue_pc;
> diff --git a/gdb/testsuite/gdb.arch/powerpc-prologue-frame.S b/gdb/testsuite/gdb.arch/powerpc-prologue-frame.S
> new file mode 100644
> index 0000000..e30ca23
> --- /dev/null
> +++ b/gdb/testsuite/gdb.arch/powerpc-prologue-frame.S
> @@ -0,0 +1,35 @@
> +/* This test is part of GDB, the GNU debugger.
> +
> +   Copyright 2018 Free Software Foundation, Inc.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +#include <ppc-asm.h>
> +
> +FUNC_START(foo)
> +	stwu 1,-32(1)
> +	mflr 3
> +	stw 3,36(1)
> +	stw 31,28(1)
> +	mr 31,1
> +	bl bar
> +	mr 9,3
> +	mr 3,9
> +	addi 11,31,32
> +	lwz 0,4(11)
> +	mtlr 0
> +	lwz 31,-4(11)
> +	mr 1,11
> +	blr
> +FUNC_END(foo)
> diff --git a/gdb/testsuite/gdb.arch/powerpc-prologue-frame.c b/gdb/testsuite/gdb.arch/powerpc-prologue-frame.c
> new file mode 100644
> index 0000000..8cab6f2
> --- /dev/null
> +++ b/gdb/testsuite/gdb.arch/powerpc-prologue-frame.c
> @@ -0,0 +1,28 @@
> +/* This test is part of GDB, the GNU debugger.
> +
> +   Copyright 2018 Free Software Foundation, Inc.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +int bar()
> +{
> +  return 0;
> +}
> +
> +int foo();
> +
> +int main(void)
> +{
> +  return foo();
> +}
> diff --git a/gdb/testsuite/gdb.arch/powerpc-prologue-frame.exp b/gdb/testsuite/gdb.arch/powerpc-prologue-frame.exp
> new file mode 100644
> index 0000000..d26314b
> --- /dev/null
> +++ b/gdb/testsuite/gdb.arch/powerpc-prologue-frame.exp
> @@ -0,0 +1,41 @@
> +# Copyright 2018 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>
> +
> +if {![istarget "powerpc-*-*"] } {
> +    verbose "Skipping powerpc back trace test."
> +    return
> +}
> +
> +standard_testfile .c .S
> +set binfile [standard_output_file ${testfile}]
> +
> +if {[gdb_compile \
> +      [list ${srcdir}/${subdir}/$srcfile ${srcdir}/${subdir}/$srcfile2] \
> +      "${binfile}" executable {}] != ""} {
> +    untested "failed to build $binfile"
> +    return -1
> +}
> +
> +
> +clean_restart ${binfile}
> +
> +if ![runto bar] {
> +  untested "could not run to bar"
> +  return -1
> +}
> +
> +gdb_test "bt" \
> +         "#0\[ \t\]*$hex in bar.*\r\n#1\[ \t\]*$hex in foo.*\r\n#2\[ \t\]*$hex in main.*" \
> +         "Backtrace to the main frame"
> -- 
> 2.7.4