[PATCH] Remove md_reg_eh_frame_to_debug_frame on PPC (Re: [RFC] Wrong register numbers in .dwarf_frame on Linux/PowerPC)

Alan Modra amodra@gmail.com
Fri Dec 12 13:43:00 GMT 2014


On Fri, Dec 12, 2014 at 12:43:39PM +0100, Ulrich Weigand wrote:
> Alan Modra wrote:
> > On Thu, Dec 11, 2014 at 09:27:30PM +0100, Ulrich Weigand wrote:
> > > GCC has now been changed to implement suggestion 3 here:
> > > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg00685.html
> > > 
> > > So I think we should also change GAS to match the new GCC behavior.
> > > This simply means removing the PPC-specific definition of the macro
> > > md_reg_eh_frame_to_debug_frame.
> > > 
> > > The attached patch implements this.
> > 
> > If I understand the gcc code correctly, it seems to me that the patch
> > doesn't make gas match the new gcc behaviour.  :-(
> > 
> > To be consistent with gcc, shouldn't this instead be something like
> > the following?  (It also needs another emulation file defining TE_AIX
> > to support aix < 5.)
> 
> Ah, you're right -- I hadn't considered non-Linux platforms (but then,
> they weren't supported previously either ...).   Not sure if all of these
> platforms actually use gas to create .debug_frame sections, but it would
> certainly be better to be compatible to gcc if they do.

gcc may not use gas .cfi directives to create .debug_frame but it is
possible to do so in assembly.  I'm committing the following.

This makes gas .cfi output to .debug_frame match register numbering
emitted by gcc.  md_reg_eh_frame_to_debug_frame follows the ABI,
targets not using it, notably Linux, don't.

	* config/tc-ppc.h (md_reg_eh_frame_to_debug_frame): Match current
	gcc behaviour.
	* config/te-aix.h: New file.
	* configure.tgt: Use em=aix for powerpc-aix.

diff --git a/gas/config/tc-ppc.h b/gas/config/tc-ppc.h
index 3cd9bf1..d9551c1 100644
--- a/gas/config/tc-ppc.h
+++ b/gas/config/tc-ppc.h
@@ -267,11 +267,24 @@ extern int ppc_parse_name (const char *, struct expressionS *);
 #define md_cleanup() ppc_cleanup ()
 extern void ppc_cleanup (void);
 
+#if (defined TE_AIX5 || defined TE_AIX					\
+     || defined TE_FreeBSD || defined TE_NetBSD || defined TE_LYNX)
 /* ppc uses different register numbers between .eh_frame and .debug_frame.
    This macro translates the .eh_frame register numbers to .debug_frame
    register numbers.  */
-#define md_reg_eh_frame_to_debug_frame(regno) \
-  ((regno) == 70 ? 64 /* cr2 */ : (regno))
+#define md_reg_eh_frame_to_debug_frame(regno)				\
+  ((regno) == 70 ? 64	/* cr2 */					\
+   : (regno) == 65 ? 108 /* lr */					\
+   : (regno) == 66 ? 109 /* ctr */					\
+   : (regno) >= 68 && (regno) <= 75 ? (regno) + 86 - 68 /* crN */	\
+   : (regno) == 76 ? 101 /* xer */					\
+   : (regno) >= 77 && (regno) <= 108 ? (regno) + 1124 - 77 /* vrN */	\
+   : (regno) == 109 ? 356 /* vrsave */					\
+   : (regno) == 110 ? 67 /* vscr */					\
+   : (regno) == 111 ? 99 /* spe_acc */					\
+   : (regno) == 112 ? 612 /* spefscr */					\
+   : (regno))
+#endif
 
 #define TARGET_USE_CFIPOP 1
 
diff --git a/gas/config/te-aix.h b/gas/config/te-aix.h
new file mode 100644
index 0000000..b0da4fb
--- /dev/null
+++ b/gas/config/te-aix.h
@@ -0,0 +1,22 @@
+/* Copyright (C) 2014 Free Software Foundation, Inc.
+
+   This file is part of GAS, the GNU Assembler.
+
+   GAS 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,
+   or (at your option) any later version.
+
+   GAS 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 GAS; see the file COPYING.  If not, write to the Free
+   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+#define TE_AIX
+
+#include "obj-format.h"
diff --git a/gas/configure.tgt b/gas/configure.tgt
index 853988a..0e44880 100644
--- a/gas/configure.tgt
+++ b/gas/configure.tgt
@@ -373,7 +373,7 @@ case ${generic_target} in
   ppc-*-winnt*)				fmt=coff em=pe ;;
   ppc-*-aix5.[01])			fmt=coff em=aix5 ;;
   ppc-*-aix[5-9].*)			fmt=coff em=aix5 ;;
-  ppc-*-aix*)				fmt=coff ;;
+  ppc-*-aix*)				fmt=coff em=aix ;;
   ppc-*-beos*)				fmt=coff ;;
   ppc-*-*n*bsd* | ppc-*-elf*)		fmt=elf ;;
   ppc-*-eabi* | ppc-*-sysv4*)		fmt=elf ;;

-- 
Alan Modra
Australia Development Lab, IBM



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