Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Rainer Orth]

Peter Bergner berg...@vnet.ibm.com writes:

 Hmmm, more fallout from the libgcc move.  I think I'm just going to
 use an older checkout to test with until the libgcc fallout gets fixed.

 ...
 xgcc: error: ecrti.S: No such file or directory
 xgcc: fatal error: no input files
 compilation terminated.
 make[5]: *** [ecrti.o] Error 1
 make[5]: Leaving directory
 `/home/bergner/gcc/build/gcc-mainline-476-dje/powerpc64-linux/32/libgcc'
 ...

I sent a patch for that one:

http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00300.html

plus Paolo's typo fix:

http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00302.html

Rainer

-- 
-
Rainer Orth, Center for Biotechnology, Bielefeld University

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Thu, 2011-11-03 at 14:48 +0100, Rainer Orth wrote:
 I sent a patch for that one:
 
   http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00300.html
 
 plus Paolo's typo fix:
 
   http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00302.html

Thanks, I kicked off a bootstrap with those changes.  I'll let
you know how it goes.

Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Rainer Orth]

Peter Bergner berg...@vnet.ibm.com writes:

 On Thu, 2011-11-03 at 09:13 -0500, Peter Bergner wrote:
 On Thu, 2011-11-03 at 14:48 +0100, Rainer Orth wrote:
  I sent a patch for that one:
  
 http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00300.html
  
  plus Paolo's typo fix:
  
 http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00302.html
 
 Thanks, I kicked off a bootstrap with those changes.  I'll let
 you know how it goes.

 My powerpc64-linux bootstrap completed with no errors with
 those patches.  Thanks.

Great, thanks for the confirmation.

Rainer

-- 
-
Rainer Orth, Center for Biotechnology, Bielefeld University

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Thu, 2011-11-03 at 09:13 -0500, Peter Bergner wrote:
 On Thu, 2011-11-03 at 14:48 +0100, Rainer Orth wrote:
  I sent a patch for that one:
  
  http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00300.html
  
  plus Paolo's typo fix:
  
  http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00302.html
 
 Thanks, I kicked off a bootstrap with those changes.  I'll let
 you know how it goes.

My powerpc64-linux bootstrap completed with no errors with
those patches.  Thanks.

Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[David Edelsohn]

On Tue, Nov 1, 2011 at 3:00 PM, Peter Bergner berg...@vnet.ibm.com wrote:

 +/* Fills in the label name that should be used for a 476 link stack thunk.  
 */
 +
 +void
 +get_ppc476_thunk_name (char name[32])
 +{
 +  gcc_assert (TARGET_LINK_STACK);
 +
 +  if (HAVE_GAS_HIDDEN)
 +    sprintf (name, __ppc476.get_thunk);
 +  else
 +    ASM_GENERATE_INTERNAL_LABEL (name, LPPC476_, 0);
 +}
 +
 +/* This function emits the simple thunk routine that is used to preserve
 +   the link stack on the 476 cpu.  */
 +
 +static void
 +rs6000_code_end (void)
 +{
 +  char name[32];
 +  tree decl;
 +
 +  if (!TARGET_LINK_STACK)
 +    return;
 +
 +  get_ppc476_thunk_name (name);
 +
 +  decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, get_identifier (name),
 +                    build_function_type_list (void_type_node, NULL_TREE));
 +  DECL_RESULT (decl) = build_decl (BUILTINS_LOCATION, RESULT_DECL,
 +                                  NULL_TREE, void_type_node);
 +  TREE_PUBLIC (decl) = 1;
 +  TREE_STATIC (decl) = 1;
 +
 +  if (HAVE_GAS_HIDDEN)
 +    {
 +      DECL_COMDAT_GROUP (decl) = DECL_ASSEMBLER_NAME (decl);
 +      targetm.asm_out.unique_section (decl, 0);
 +      switch_to_section (get_named_section (decl, NULL, 0));
 +      DECL_WEAK (decl) = 1;
 +      ASM_WEAKEN_DECL (asm_out_file, decl, name, 0);
 +      targetm.asm_out.globalize_label (asm_out_file, name);
 +      targetm.asm_out.assemble_visibility (decl, VISIBILITY_HIDDEN);
 +      ASM_DECLARE_FUNCTION_NAME (asm_out_file, name, decl);
 +    }
 +  else
 +    {
 +      switch_to_section (text_section);
 +      ASM_OUTPUT_LABEL (asm_out_file, name);
 +    }
 +
 +  DECL_INITIAL (decl) = make_node (BLOCK);
 +  current_function_decl = decl;
 +  init_function_start (decl);
 +  first_function_block_is_cold = false;
 +  /* Make sure unwind info is emitted for the thunk if needed.  */
 +  final_start_function (emit_barrier (), asm_out_file, 1);
 +
 +  fputs (\tblr\n, asm_out_file);
 +
 +  final_end_function ();
 +  init_insn_lengths ();
 +  free_after_compilation (cfun);
 +  set_cfun (NULL);
 +  current_function_decl = NULL;

The two new functions have mistakes because I did not realize the
semantics of HAVE_GAS_HIDDEN.  HAVE_GAS_HIDDEN is not a macro to be
tested at runtime, but a macro tested at compile time.

if (HAVE_GAS_HIDDEN)

should be

#ifdef HAVE_GAS_HIDDEN

Please correct.

Thanks, David

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Iain Sandoe]

On 2 Nov 2011, at 17:18, David Edelsohn wrote:

On Tue, Nov 1, 2011 at 3:00 PM, Peter Bergner berg...@vnet.ibm.com  
wrote:


+/* Fills in the label name that should be used for a 476 link  
stack thunk.  */

+
+void
+get_ppc476_thunk_name (char name[32])
+{
+  gcc_assert (TARGET_LINK_STACK);
+
+  if (HAVE_GAS_HIDDEN)
+sprintf (name, __ppc476.get_thunk);
+  else
+ASM_GENERATE_INTERNAL_LABEL (name, LPPC476_, 0);
+}
+
+/* This function emits the simple thunk routine that is used to  
preserve

+   the link stack on the 476 cpu.  */
+
+static void
+rs6000_code_end (void)
+{
+  char name[32];
+  tree decl;
+
+  if (!TARGET_LINK_STACK)
+return;
+
+  get_ppc476_thunk_name (name);
+
+  decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL,  
get_identifier (name),
+build_function_type_list (void_type_node,  
NULL_TREE));

+  DECL_RESULT (decl) = build_decl (BUILTINS_LOCATION, RESULT_DECL,
+  NULL_TREE, void_type_node);
+  TREE_PUBLIC (decl) = 1;
+  TREE_STATIC (decl) = 1;
+
+  if (HAVE_GAS_HIDDEN)
+{
+  DECL_COMDAT_GROUP (decl) = DECL_ASSEMBLER_NAME (decl);
+  targetm.asm_out.unique_section (decl, 0);
+  switch_to_section (get_named_section (decl, NULL, 0));
+  DECL_WEAK (decl) = 1;
+  ASM_WEAKEN_DECL (asm_out_file, decl, name, 0);
+  targetm.asm_out.globalize_label (asm_out_file, name);
+  targetm.asm_out.assemble_visibility (decl, VISIBILITY_HIDDEN);
+  ASM_DECLARE_FUNCTION_NAME (asm_out_file, name, decl);
+}
+  else
+{
+  switch_to_section (text_section);
+  ASM_OUTPUT_LABEL (asm_out_file, name);
+}
+
+  DECL_INITIAL (decl) = make_node (BLOCK);
+  current_function_decl = decl;
+  init_function_start (decl);
+  first_function_block_is_cold = false;
+  /* Make sure unwind info is emitted for the thunk if needed.  */
+  final_start_function (emit_barrier (), asm_out_file, 1);
+
+  fputs (\tblr\n, asm_out_file);
+
+  final_end_function ();
+  init_insn_lengths ();
+  free_after_compilation (cfun);
+  set_cfun (NULL);
+  current_function_decl = NULL;


The two new functions have mistakes because I did not realize the
semantics of HAVE_GAS_HIDDEN.  HAVE_GAS_HIDDEN is not a macro to be
tested at runtime, but a macro tested at compile time.

if (HAVE_GAS_HIDDEN)

should be

#ifdef HAVE_GAS_HIDDEN


also in macho_branch_islands () :

  if (TARGET_LINK_STACK)
{
  char name[32];
  get_ppc64_thunk_name (name);
  strcat (tmp_buf, :\n\tmflr r0\n\tbl );
  strcat (tmp_buf, name);
  strcat (tmp_buf, \n);
  strcat (tmp_buf, label);
  strcat (tmp_buf, _pic:\n\tmflr r11\n);
}
  else

which breaks bootstrap for darwin - I'm not sure why you have an entry  
here (this is mach-o-specific code)

 - I doubt there will ever be a mach-o implementation with a PPC476 -
but, in any case the call to get_ppc64_thunk_name needs wrapping  
somehow.


cheers
Iain

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Wed, 2011-11-02 at 18:17 +, Iain Sandoe wrote:
 also in macho_branch_islands () :
 
 if (TARGET_LINK_STACK)
   {
 char name[32];
 get_ppc64_thunk_name (name);
 strcat (tmp_buf, :\n\tmflr r0\n\tbl );
 strcat (tmp_buf, name);
 strcat (tmp_buf, \n);
 strcat (tmp_buf, label);
 strcat (tmp_buf, _pic:\n\tmflr r11\n);
   }
 else
 
 which breaks bootstrap for darwin - I'm not sure why you have an entry  
 here (this is mach-o-specific code)
   - I doubt there will ever be a mach-o implementation with a PPC476 -
 but, in any case the call to get_ppc64_thunk_name needs wrapping  
 somehow.

How is it failing for you?  And what are your configure options so
I can try and recreate the error?

If it's similar to what Alan saw but for get_ppc64_thunk_name, namely:

rs6000.c:27968:1: error: 'void rs6000_code_end()' defined but not used
[-Werror=unused-function]
cc1plus: all warnings being treated as errors

Does the following fix it for you?

Index: config/rs6000/rs6000-protos.h
===
--- config/rs6000/rs6000-protos.h   (revision 180786)
+++ config/rs6000/rs6000-protos.h   (working copy)
@@ -173,7 +173,7 @@ extern void rs6000_emit_eh_reg_restore (
 extern const char * output_isel (rtx *);
 extern void rs6000_call_indirect_aix (rtx, rtx, rtx);
 extern void rs6000_aix_asm_output_dwarf_table_ref (char *);
-extern void get_ppc476_thunk_name (char name[32]);
+extern void get_ppc476_thunk_name (char name[32]) ATTRIBUTE_UNUSED;
 
 /* Declare functions in rs6000-c.c */


Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Wed, 2011-11-02 at 13:18 -0400, David Edelsohn wrote:
 The two new functions have mistakes because I did not realize the
 semantics of HAVE_GAS_HIDDEN.  HAVE_GAS_HIDDEN is not a macro to be
 tested at runtime, but a macro tested at compile time.

I'm sorry, I didn't realize that either.  Does the following fix
your problem?

Peter


* config/rs6000/rs6000.c (USE_HIDDEN_LINKONCE): New define.
(get_ppc476_thunk_name): Use it.
(rs6000_code_end): Likewise.

Index: config/rs6000/rs6000.c
===
--- config/rs6000/rs6000.c  (revision 180786)
+++ config/rs6000/rs6000.c  (working copy)
@@ -27949,6 +27949,12 @@ rs6000_save_toc_in_prologue_p (void)
   return (cfun  cfun-machine  cfun-machine-save_toc_in_prologue);
 }
 
+#ifdef HAVE_GAS_HIDDEN
+# define USE_HIDDEN_LINKONCE 1
+#else
+# define USE_HIDDEN_LINKONCE 0
+#endif
+
 /* Fills in the label name that should be used for a 476 link stack thunk.  */
 
 void
@@ -27956,7 +27962,7 @@ get_ppc476_thunk_name (char name[32])
 {
   gcc_assert (TARGET_LINK_STACK);
 
-  if (HAVE_GAS_HIDDEN)
+  if (USE_HIDDEN_LINKONCE)
 sprintf (name, __ppc476.get_thunk);
   else
 ASM_GENERATE_INTERNAL_LABEL (name, LPPC476_, 0);
@@ -27983,7 +27989,7 @@ rs6000_code_end (void)
   TREE_PUBLIC (decl) = 1;
   TREE_STATIC (decl) = 1;
 
-  if (HAVE_GAS_HIDDEN)
+  if (USE_HIDDEN_LINKONCE)
 {
   DECL_COMDAT_GROUP (decl) = DECL_ASSEMBLER_NAME (decl);
   targetm.asm_out.unique_section (decl, 0);

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Iain Sandoe]

On 2 Nov 2011, at 18:34, Peter Bergner wrote:


On Wed, 2011-11-02 at 18:17 +, Iain Sandoe wrote:

also in macho_branch_islands () :

  if (TARGET_LINK_STACK)
{
  char name[32];
  get_ppc64_thunk_name (name);
  strcat (tmp_buf, :\n\tmflr r0\n\tbl );
  strcat (tmp_buf, name);
  strcat (tmp_buf, \n);
  strcat (tmp_buf, label);
  strcat (tmp_buf, _pic:\n\tmflr r11\n);
}
  else

which breaks bootstrap for darwin - I'm not sure why you have an  
entry

here (this is mach-o-specific code)
 - I doubt there will ever be a mach-o implementation with a PPC476 -
but, in any case the call to get_ppc64_thunk_name needs wrapping
somehow.


How is it failing for you?  And what are your configure options so
I can try and recreate the error?


/GCC/gcc-live-trunk/gcc/config/rs6000/rs6000.c: In function ‘void  
macho_branch_islands()’:
/GCC/gcc-live-trunk/gcc/config/rs6000/rs6000.c:25074:34: error:  
‘get_ppc64_thunk_name’ was not declared in this scope

make[3]: *** [rs6000.o] Error 1
make[3]: *** Waiting for unfinished jobs


/GCC/gcc-live-trunk/configure --prefix=/GCC/gcc-4-7-tempi -- 
target=powerpc-apple-darwin9 --host=powerpc-apple-darwin9 -- 
build=powerpc-apple-darwin9 --enable-version-specific-runtime-libs -- 
enable-checking=yes --with-libiconv-prefix=/usr --with-system-zlib -- 
with-gmp=/GCC/multiprec-math/ppc --with-mpfr=/GCC/multiprec-math/ppc   
--with-mpc=/GCC/multiprec-math/ppc --enable-languages=c,c+ 
+,fortran,ada,objc,obj-c++,lto


etc..

===

Hmm .. I wonder if this is just a temporary glitch because of the move  
of files to libgcc.


I'll investigate a bit further later...


If it's similar to what Alan saw but for get_ppc64_thunk_name, namely:

rs6000.c:27968:1: error: 'void rs6000_code_end()' defined but not used
[-Werror=unused-function]
cc1plus: all warnings being treated as errors

Does the following fix it for you?

Index: config/rs6000/rs6000-protos.h
===
--- config/rs6000/rs6000-protos.h   (revision 180786)
+++ config/rs6000/rs6000-protos.h   (working copy)
@@ -173,7 +173,7 @@ extern void rs6000_emit_eh_reg_restore (
extern const char * output_isel (rtx *);
extern void rs6000_call_indirect_aix (rtx, rtx, rtx);
extern void rs6000_aix_asm_output_dwarf_table_ref (char *);
-extern void get_ppc476_thunk_name (char name[32]);
+extern void get_ppc476_thunk_name (char name[32]) ATTRIBUTE_UNUSED;

/* Declare functions in rs6000-c.c */


We do include this in tm_p.h

$ more ../gcc-4-7-trunk-build/gcc/tm_p.h
#ifndef GCC_TM_P_H
#define GCC_TM_P_H
#ifdef IN_GCC
# include config/rs6000/rs6000-protos.h
# include config/darwin-protos.h
# include tm-preds.h
#endif
#endif /* GCC_TM_P_H */

.. but not in tm.h

Iain

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Wed, 2011-11-02 at 18:52 +, Iain Sandoe wrote:
 Hmm .. I wonder if this is just a temporary glitch because of the move  
 of files to libgcc.

Note that I just hit a problem with the libgcc move.  We need:

Index: libgcc/config/rs6000/t-ppccomm
===
--- libgcc/config/rs6000/t-ppccomm  (revision 180786)
+++ libgcc/config/rs6000/t-ppccomm  (working copy)
@@ -7,7 +7,7 @@ LIB2ADD_ST += \
   $(srcdir)/config/rs6000/crtresfpr.S \
   $(srcdir)/config/rs6000/crtsavgpr.S \
   $(srcdir)/config/rs6000/crtresgpr.S \
-  $(srcdir)/config/rs6000/crtresxfpr.S 
+  $(srcdir)/config/rs6000/crtresxfpr.S \
   $(srcdir)/config/rs6000/crtresxgpr.S \
   $(srcdir)/config/rs6000/e500crtres32gpr.S \
   $(srcdir)/config/rs6000/e500crtres64gpr.S \
@@ -21,7 +21,7 @@ LIB2ADD_ST += \
   $(srcdir)/config/rs6000/e500crtsav64gprctr.S \
   $(srcdir)/config/rs6000/e500crtsavg32gpr.S \
   $(srcdir)/config/rs6000/e500crtsavg64gpr.S \
-  $(srcdir)/config/rs6000/e500crtsavg64gprctr.S
+  $(srcdir)/config/rs6000/e500crtsavg64gprctr.S \
   $(srcdir)/config/rs6000/eabi.S

I'm continuing my build to see if there's anything more that falls
out from that...or my patch :(.


 I'll investigate a bit further later...

So you didn't start your build from scratch?  I'll keep my
fingers crossed that a fresh build fixing things for you.
Otherwise, let me know what you find.

Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Wed, 2011-11-02 at 19:33 +, Iain Sandoe wrote:
 I'm going to try this 
 
 $ svn diff -x -p gcc/config/rs6000/rs6000.c
 Index: gcc/config/rs6000/rs6000.c
 ===
 --- gcc/config/rs6000/rs6000.c  (revision 180788)
 +++ gcc/config/rs6000/rs6000.c  (working copy)
 @@ -25071,7 +25071,7 @@ macho_branch_islands (void)
if (TARGET_LINK_STACK)
  {
char name[32];
 - get_ppc64_thunk_name (name);
 + get_ppc476_thunk_name (name);
strcat (tmp_buf, :\n\tmflr r0\n\tbl );
strcat (tmp_buf, name);
strcat (tmp_buf, \n);


Oh my, I'm not sure how that got through. :(  Oh, as you
said, that is TARGET_MACHO which I can't really test.
Sorry about that.




 @@ -27956,10 +27956,11 @@ get_ppc476_thunk_name (char name[32])
   {
 gcc_assert (TARGET_LINK_STACK);
 
 -  if (HAVE_GAS_HIDDEN)
 +#if defined(HAVE_GAS_HIDDEN)
   sprintf (name, __ppc476.get_thunk);
 -  else
 +#else
   ASM_GENERATE_INTERNAL_LABEL (name, LPPC476_, 0);
 +#endif
   }
...

Instead of that, see my patch to fix David's AIX problem:

  http://gcc.gnu.org/ml/gcc-patches/2011-11/msg00198.html


Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Wed, 2011-11-02 at 14:05 -0500, Peter Bergner wrote:
 On Wed, 2011-11-02 at 18:52 +, Iain Sandoe wrote:
  Hmm .. I wonder if this is just a temporary glitch because of the move  
  of files to libgcc.
 
 Note that I just hit a problem with the libgcc move.  We need:
 
 Index: libgcc/config/rs6000/t-ppccomm
 ===
 --- libgcc/config/rs6000/t-ppccomm(revision 180786)
 +++ libgcc/config/rs6000/t-ppccomm(working copy)
 @@ -7,7 +7,7 @@ LIB2ADD_ST += \
  $(srcdir)/config/rs6000/crtresfpr.S \
  $(srcdir)/config/rs6000/crtsavgpr.S \
  $(srcdir)/config/rs6000/crtresgpr.S \
 -$(srcdir)/config/rs6000/crtresxfpr.S 
 +$(srcdir)/config/rs6000/crtresxfpr.S \
  $(srcdir)/config/rs6000/crtresxgpr.S \
  $(srcdir)/config/rs6000/e500crtres32gpr.S \
  $(srcdir)/config/rs6000/e500crtres64gpr.S \
 @@ -21,7 +21,7 @@ LIB2ADD_ST += \
  $(srcdir)/config/rs6000/e500crtsav64gprctr.S \
  $(srcdir)/config/rs6000/e500crtsavg32gpr.S \
  $(srcdir)/config/rs6000/e500crtsavg64gpr.S \
 -$(srcdir)/config/rs6000/e500crtsavg64gprctr.S
 +$(srcdir)/config/rs6000/e500crtsavg64gprctr.S \
  $(srcdir)/config/rs6000/eabi.S
 
 I'm continuing my build to see if there's anything more that falls
 out from that...or my patch :(.

Hmmm, more fallout from the libgcc move.  I think I'm just going to
use an older checkout to test with until the libgcc fallout gets fixed.

...
xgcc: error: ecrti.S: No such file or directory
xgcc: fatal error: no input files
compilation terminated.
make[5]: *** [ecrti.o] Error 1
make[5]: Leaving directory
`/home/bergner/gcc/build/gcc-mainline-476-dje/powerpc64-linux/32/libgcc'
...


Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Iain Sandoe]

On 2 Nov 2011, at 19:39, Peter Bergner wrote:


On Wed, 2011-11-02 at 19:33 +, Iain Sandoe wrote:

I'm going to try this 
  char name[32];
- get_ppc64_thunk_name (name);
+ get_ppc476_thunk_name (name);


This (together with the changes for HAVE_GAS_HIDDEN) fixes my  
bootstrap problem.



Oh my, I'm not sure how that got through. :(


Well, I guess I should have looked at your patch before it hit trunk  
(I was mistakenly thinking it didn't touch Darwin).



Oh, as you said, that is TARGET_MACHO which I can't really test.
Sorry about that.


FWIW, it's not really any worse building a cross from linux -  
darwin9*** than a cross to any other foreign OS from linux (there are  
a couple of differences - because of the non-binutils tool-chain).  I  
did it recently.


** Rainer, AFAICT, all is OK with your (much appreciated)  
rationalization of libgcc on *-Darwin9  x86-64-Darwin10 (although  
testing is incomplete).


cheers
Iain

***
x86-64-darwin10 and Darwin11 are more problematic, since the cross  
toolchains are not yet in place/mature (at least as of a few weeks ago).

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Wed, 2011-11-02 at 22:02 +, Iain Sandoe wrote:
 On 2 Nov 2011, at 19:39, Peter Bergner wrote:
 
  On Wed, 2011-11-02 at 19:33 +, Iain Sandoe wrote:
  I'm going to try this 
char name[32];
  - get_ppc64_thunk_name (name);
  + get_ppc476_thunk_name (name);
 
 This (together with the changes for HAVE_GAS_HIDDEN) fixes my  
 bootstrap problem.

Ok, I committed the following as obvious.  Sorry to you and David
for the breakage.

Peter


2011-11-02  Peter Bergner  berg...@vnet.ibm.com
Iain Sandoe  ia...@gcc.gnu.org

* config/rs6000/rs6000.c (USE_HIDDEN_LINKONCE): New define.
(get_ppc476_thunk_name): Use it.
(rs6000_code_end): Likewise.
(macho_branch_islands): Fix typo.

Index: gcc/config/rs6000/rs6000.c
===
--- gcc/config/rs6000/rs6000.c  (revision 180813)
+++ gcc/config/rs6000/rs6000.c  (working copy)
@@ -25071,7 +25071,7 @@ macho_branch_islands (void)
  if (TARGET_LINK_STACK)
{
  char name[32];
- get_ppc64_thunk_name (name);
+ get_ppc476_thunk_name (name);
  strcat (tmp_buf, :\n\tmflr r0\n\tbl );
  strcat (tmp_buf, name);
  strcat (tmp_buf, \n);
@@ -27949,6 +27949,12 @@ rs6000_save_toc_in_prologue_p (void)
   return (cfun  cfun-machine  cfun-machine-save_toc_in_prologue);
 }
 
+#ifdef HAVE_GAS_HIDDEN
+# define USE_HIDDEN_LINKONCE 1
+#else
+# define USE_HIDDEN_LINKONCE 0
+#endif
+
 /* Fills in the label name that should be used for a 476 link stack thunk.  */
 
 void
@@ -27956,7 +27962,7 @@ get_ppc476_thunk_name (char name[32])
 {
   gcc_assert (TARGET_LINK_STACK);
 
-  if (HAVE_GAS_HIDDEN)
+  if (USE_HIDDEN_LINKONCE)
 sprintf (name, __ppc476.get_thunk);
   else
 ASM_GENERATE_INTERNAL_LABEL (name, LPPC476_, 0);
@@ -27983,7 +27989,7 @@ rs6000_code_end (void)
   TREE_PUBLIC (decl) = 1;
   TREE_STATIC (decl) = 1;
 
-  if (HAVE_GAS_HIDDEN)
+  if (USE_HIDDEN_LINKONCE)
 {
   DECL_COMDAT_GROUP (decl) = DECL_ASSEMBLER_NAME (decl);
   targetm.asm_out.unique_section (decl, 0);

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Mon, 2011-10-31 at 19:05 -0400, David Edelsohn wrote:
 Okay, go ahead with PPC64 support as well.  Hopefully no one ever will
 have to use it.  That implies the option should not explicitly
 reference ppc476.

Ok, for completeness, I attached what I committed below, which includes
the support for 64-bit because it makes the code cleaner and changes
the option name back to -mpreserve-link-stack.  Thanks.

Peter


* config.gcc (powerpc*-*-linux*): Add powerpc*-*-linux*ppc476* variant.
* config/rs6000/476.h: New file.
* config/rs6000/476.opt: Likewise.
* config/rs6000/rs6000.h (TARGET_LINK_STACK): New define.
(SET_TARGET_LINK_STACK): Likewise.
(TARGET_ASM_CODE_END): Define.
* config/rs6000/rs6000.c (rs6000_option_override_internal): Enable
TARGET_LINK_STACK for -mtune=476 and -mtune=476fp.
(rs6000_legitimize_tls_address): Emit the link stack preserving GOT
code if TARGET_LINK_STACK.
(rs6000_emit_load_toc_table): Likewise.
(output_function_profiler): Likewise
(macho_branch_islands): Likewise
(machopic_output_stub): Likewise
(get_ppc476_thunk_name): New function.
(rs6000_code_end): Likewise.
* config/rs6000/rs6000.md (load_toc_v4_PIC_1, load_toc_v4_PIC_1b):
Convert to a define_expand.
(load_toc_v4_PIC_1_normal): New define_insn.
(load_toc_v4_PIC_1_476): Likewise.
(load_toc_v4_PIC_1b_normal): Likewise.
(load_toc_v4_PIC_1b_476): Likewise.

Index: gcc/config.gcc
===
--- gcc/config.gcc  (revision 180740)
+++ gcc/config.gcc  (revision 180741)
@@ -2145,6 +2145,9 @@ powerpc-*-linux* | powerpc64-*-linux*)
esac
tmake_file=${tmake_file} t-slibgcc-libgcc
case ${target} in
+   powerpc*-*-linux*ppc476*)
+   tm_file=${tm_file} rs6000/476.h
+   extra_options=${extra_options} rs6000/476.opt ;;
powerpc*-*-linux*altivec*)
tm_file=${tm_file} rs6000/linuxaltivec.h ;;
powerpc*-*-linux*spe*)
Index: gcc/config/rs6000/476.h
===
--- gcc/config/rs6000/476.h (revision 0)
+++ gcc/config/rs6000/476.h (revision 180741)
@@ -0,0 +1,32 @@
+/* Enable IBM PowerPC 476 support.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+   Contributed by Peter Bergner (berg...@vnet.ibm.com)
+   This file is part of GCC.
+
+   GCC 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.
+
+   GCC 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.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   http://www.gnu.org/licenses/.  */
+
+#undef TARGET_LINK_STACK
+#define TARGET_LINK_STACK (rs6000_link_stack)
+
+#undef SET_TARGET_LINK_STACK
+#define SET_TARGET_LINK_STACK(X) do { TARGET_LINK_STACK = (X); } while (0)
+
+#undef TARGET_ASM_CODE_END
+#define TARGET_ASM_CODE_END rs6000_code_end
Index: gcc/config/rs6000/rs6000-protos.h
===
--- gcc/config/rs6000/rs6000-protos.h   (revision 180740)
+++ gcc/config/rs6000/rs6000-protos.h   (revision 180741)
@@ -173,6 +173,7 @@ extern void rs6000_emit_eh_reg_restore (
 extern const char * output_isel (rtx *);
 extern void rs6000_call_indirect_aix (rtx, rtx, rtx);
 extern void rs6000_aix_asm_output_dwarf_table_ref (char *);
+extern void get_ppc476_thunk_name (char name[32]);
 
 /* Declare functions in rs6000-c.c */
 
Index: gcc/config/rs6000/476.opt
===
--- gcc/config/rs6000/476.opt   (revision 0)
+++ gcc/config/rs6000/476.opt   (revision 180741)
@@ -0,0 +1,24 @@
+; IBM PowerPC 476 options.
+;
+; Copyright (C) 2011 Free Software Foundation, Inc.
+; Contributed by Peter Bergner (berg...@vnet.ibm.com)
+;
+; This file is part of GCC.
+;
+; GCC 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.
+;
+; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+; WARRANTY; without even the implied warranty 

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Alan Modra]

On Tue, Nov 01, 2011 at 02:00:25PM -0500, Peter Bergner wrote:
   (get_ppc476_thunk_name): New function.
   (rs6000_code_end): Likewise.

rs6000.c:27968:1: error: 'void rs6000_code_end()' defined but not used 
[-Werror=unused-function]
cc1plus: all warnings being treated as errors

Bootstrapped and committed as obvious, revision 180761.

* config/rs6000/rs6000.c (rs6000_code_end): Declare ATTRIBUTE_UNUSED.

Index: gcc/config/rs6000/rs6000.c
===
--- gcc/config/rs6000/rs6000.c  (revision 180754)
+++ gcc/config/rs6000/rs6000.c  (working copy)
@@ -1176,6 +1176,7 @@ static void rs6000_trampoline_init (rtx,
 static bool rs6000_cannot_force_const_mem (enum machine_mode, rtx);
 static bool rs6000_legitimate_constant_p (enum machine_mode, rtx);
 static bool rs6000_save_toc_in_prologue_p (void);
+static void rs6000_code_end (void) ATTRIBUTE_UNUSED;
 
 /* Hash table stuff for keeping track of TOC entries.  */
 
-- 
Alan Modra
Australia Development Lab, IBM

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Fri, 2011-10-28 at 15:37 -0400, David Edelsohn wrote:
 On Fri, Oct 28, 2011 at 12:36 PM, Peter Bergner berg...@vnet.ibm.com wrote:
 
  So David, do we even want to bother trying to support this on -m64
  given the only cpu that needs this is a 32-bit only cpu?  If so, I
  can try and work with Alan to figure out how we can merge the
  function descriptors for the thunk routines when using -m64.
 
 I barely want to bother with this ;-).  So, no, I don't want to bother
 with -m64 support.

Ok, attached below is the updated patch that passes bootstrap and regtesting
that only enables the new link stack code for 32-bit compiles.  However,
talking with Alan, he mentioned we just have to mark the opd entry weak
and that will fix my link problem (confirmed it does).  It seems we might
want to allow this on 64-bit too, since it actually makes the code cleaner
wrt where we set TARGET_LINK_STACK.  To get 64-bit working, we only need the
following patch on top of the 32-bit only patch below:

--- gcc/config/rs6000/rs6000.c.old  2011-10-31 16:16:04.0 -0500
+++ gcc/config/rs6000/rs6000.c  2011-10-31 16:16:37.0 -0500
@@ -3245,13 +3245,7 @@
 
   /* If not explicitly specified via option, decide whether to generate the
  extra blr's required to preserve the link stack on some cpus (eg, 476).  
*/
-  if (TARGET_POWERPC64)
-{
-  if (TARGET_LINK_STACK  0)
-   warning (0, -m64 disables -mpreserve-ppc476-link-stack);
-  SET_TARGET_LINK_STACK (0);
-}
-  else if (TARGET_LINK_STACK == -1)
+  if (TARGET_LINK_STACK == -1)
 SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476  flag_pic);
 
   return ret;
@@ -27960,6 +27954,8 @@
   DECL_COMDAT_GROUP (decl) = DECL_ASSEMBLER_NAME (decl);
   targetm.asm_out.unique_section (decl, 0);
   switch_to_section (get_named_section (decl, NULL, 0));
+  DECL_WEAK (decl) = 1;
+  ASM_WEAKEN_DECL (asm_out_file, decl, name, 0);
   targetm.asm_out.globalize_label (asm_out_file, name);
   targetm.asm_out.assemble_visibility (decl, VISIBILITY_HIDDEN);
   ASM_DECLARE_FUNCTION_NAME (asm_out_file, name, decl);

It's up to you David whether we should stick with the 32-bit only
patch or go ahead and allow 64-bit too.  What do you think?

Peter



* config.gcc (powerpc*-*-linux*): Add powerpc*-*-linux*ppc476* variant.
* config/rs6000/476.h: New file.
* config/rs6000/476.opt: Likewise.
* config/rs6000/rs6000.h (TARGET_LINK_STACK): New define.
(SET_TARGET_LINK_STACK): Likewise.
(TARGET_ASM_CODE_END): Define.
* config/rs6000/rs6000.c (rs6000_option_override_internal): Enable
TARGET_LINK_STACK for -mtune=476 and -mtune=476fp.
(rs6000_legitimize_tls_address): Emit the link stack preserving GOT
code if TARGET_LINK_STACK.
(rs6000_emit_load_toc_table): Likewise.
(output_function_profiler): Likewise
(macho_branch_islands): Likewise
(machopic_output_stub): Likewise
(get_ppc476_thunk_name): New function.
(rs6000_code_end): Likewise.
* config/rs6000/rs6000.md (load_toc_v4_PIC_1, load_toc_v4_PIC_1b):
Convert to a define_expand.
(load_toc_v4_PIC_1_normal): New define_insn.
(load_toc_v4_PIC_1_476): Likewise.
(load_toc_v4_PIC_1b_normal): Likewise.
(load_toc_v4_PIC_1b_476): Likewise.

Index: gcc/config.gcc
===
--- gcc/config.gcc  (revision 179091)
+++ gcc/config.gcc  (working copy)
@@ -2133,6 +2133,9 @@ powerpc-*-linux* | powerpc64-*-linux*)
esac
tmake_file=${tmake_file} t-slibgcc-libgcc
case ${target} in
+   powerpc*-*-linux*ppc476*)
+   tm_file=${tm_file} rs6000/476.h
+   extra_options=${extra_options} rs6000/476.opt ;;
powerpc*-*-linux*altivec*)
tm_file=${tm_file} rs6000/linuxaltivec.h ;;
powerpc*-*-linux*spe*)
Index: gcc/config/rs6000/476.h
===
--- gcc/config/rs6000/476.h (revision 0)
+++ gcc/config/rs6000/476.h (revision 0)
@@ -0,0 +1,32 @@
+/* Enable IBM PowerPC 476 support.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+   Contributed by Peter Bergner (berg...@vnet.ibm.com)
+   This file is part of GCC.
+
+   GCC 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.
+
+   GCC 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.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as 

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[David Edelsohn]

On Mon, Oct 31, 2011 at 5:32 PM, Peter Bergner berg...@vnet.ibm.com wrote:

 Ok, attached below is the updated patch that passes bootstrap and regtesting
 that only enables the new link stack code for 32-bit compiles.  However,
 talking with Alan, he mentioned we just have to mark the opd entry weak
 and that will fix my link problem (confirmed it does).  It seems we might
 want to allow this on 64-bit too, since it actually makes the code cleaner
 wrt where we set TARGET_LINK_STACK.  To get 64-bit working, we only need the
 following patch on top of the 32-bit only patch below:

Okay, go ahead with PPC64 support as well.  Hopefully no one ever will
have to use it.  That implies the option should not explicitly
reference ppc476.

- David

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Richard Henderson]

On 10/27/2011 06:43 PM, Peter Bergner wrote:
 Ok, here's a patch to implement that, and it passes bootstrap and
 regtesting.  Richard, is this what you had in mind?  I'll note that
 I disabled rs6000_code_end for TARGET_POWERPC64, since I was running
 into linker errors when building libgcc.  The merging of the thunk
 routines with comdat worked fine, but the thunk function also has a
 function descriptor and I couldn't figure out a way to get those
 merged properly (if it's even possible), so they led to multiply
 defined symbol linker errors.

That's something you might have to discuss with David and Alan.

You might wind up bypassing some of the normal boilerplate
that gets added by final_start_function etc.

It does look like you're missing the stub for ppc64, and yet
you invoke it?  At least, I don't see anything earlier that
tests ppc64, only in rs6000_code_end.


r~

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Fri, 2011-10-28 at 08:20 -0700, Richard Henderson wrote:
 On 10/27/2011 06:43 PM, Peter Bergner wrote:
  Ok, here's a patch to implement that, and it passes bootstrap and
  regtesting.  Richard, is this what you had in mind?  I'll note that
  I disabled rs6000_code_end for TARGET_POWERPC64, since I was running
  into linker errors when building libgcc.  The merging of the thunk
  routines with comdat worked fine, but the thunk function also has a
  function descriptor and I couldn't figure out a way to get those
  merged properly (if it's even possible), so they led to multiply
  defined symbol linker errors.
 
 That's something you might have to discuss with David and Alan.

So David, do we even want to bother trying to support this on -m64
given the only cpu that needs this is a 32-bit only cpu?  If so, I
can try and work with Alan to figure out how we can merge the
function descriptors for the thunk routines when using -m64.



 It does look like you're missing the stub for ppc64, and yet
 you invoke it?  At least, I don't see anything earlier that
 tests ppc64, only in rs6000_code_end.

Oops, you're write.  Had I compiled with -m64 -mcpu=power7 -mtune=476fp,
I would have caught that.  I guess (supposing we don't want to support
64-bit) I should have the following hunks instead, correct?

+  /* If not explicitly specified via option, decide whether to generate the
+ extra blr's required to preserve the link stack on some cpus (eg, 476).  
*/
+  if (TARGET_LINK_STACK == -1)
+SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476
+   flag_pic
+   !TARGET_POWERPC64);
+


+static void
+rs6000_code_end (void)
+{
+  char name[32];
+  tree decl;
+
+  if (!TARGET_LINK_STACK)
+return;
...



Peter


~   

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Richard Henderson]

On 10/28/2011 09:36 AM, Peter Bergner wrote:
 Oops, you're write.  Had I compiled with -m64 -mcpu=power7 -mtune=476fp,
 I would have caught that.  I guess (supposing we don't want to support
 64-bit) I should have the following hunks instead, correct?
 
 +  /* If not explicitly specified via option, decide whether to generate the
 + extra blr's required to preserve the link stack on some cpus (eg, 476). 
  */
 +  if (TARGET_LINK_STACK == -1)
 +SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476
 +   flag_pic
 +   !TARGET_POWERPC64);

Not quite.  You can't allow the user to set TARGET_LINK_STACK either,
for 64-bit.  Because it won't work without further fixups.  More like

  if (TARGET_POWERPC64)
SET_TARGET_LINK_STACK (0);
  if (TARGET_LINK_STACK == -1)
SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476  flag_pic);

That first test could possibly be more refined, like testing AIX
calling conventions or DOT_SYMBOLS.  But it hardly seems worthwhile.


r~

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Fri, 2011-10-28 at 09:44 -0700, Richard Henderson wrote:
 Not quite.  You can't allow the user to set TARGET_LINK_STACK either,
 for 64-bit.  Because it won't work without further fixups.  More like
 
   if (TARGET_POWERPC64)
 SET_TARGET_LINK_STACK (0);
   if (TARGET_LINK_STACK == -1)
 SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476  flag_pic);

Ah, I forgot about if the user explicitly uses -mpreserve-ppc476-link-stack.
Ok, so how about if we also spit out a warning that we're implicitly disabling
the link stack code rather than doing it silently?  Like so:

  if (TARGET_POWERPC64)
{
  if (TARGET_LINK_STACK  0)
warning (0, -m64 disables -mpreserve-ppc476-link-stack);
  SET_TARGET_LINK_STACK (0);
}
  else if (TARGET_LINK_STACK == -1)
SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476  flag_pic);


Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Richard Henderson]

On 10/28/2011 11:35 AM, Peter Bergner wrote:
 On Fri, 2011-10-28 at 09:44 -0700, Richard Henderson wrote:
 Not quite.  You can't allow the user to set TARGET_LINK_STACK either,
 for 64-bit.  Because it won't work without further fixups.  More like

   if (TARGET_POWERPC64)
 SET_TARGET_LINK_STACK (0);
   if (TARGET_LINK_STACK == -1)
 SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476  flag_pic);
 
 Ah, I forgot about if the user explicitly uses -mpreserve-ppc476-link-stack.
 Ok, so how about if we also spit out a warning that we're implicitly disabling
 the link stack code rather than doing it silently?  Like so:
 
   if (TARGET_POWERPC64)
 {
   if (TARGET_LINK_STACK  0)
   warning (0, -m64 disables -mpreserve-ppc476-link-stack);
   SET_TARGET_LINK_STACK (0);
 }
   else if (TARGET_LINK_STACK == -1)
 SET_TARGET_LINK_STACK (rs6000_cpu == PROCESSOR_PPC476  flag_pic);

Fine by me.  Final rs6000 approval is dje's bivouac.


r~

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[David Edelsohn]

On Fri, Oct 28, 2011 at 12:36 PM, Peter Bergner berg...@vnet.ibm.com wrote:

 So David, do we even want to bother trying to support this on -m64
 given the only cpu that needs this is a 32-bit only cpu?  If so, I
 can try and work with Alan to figure out how we can merge the
 function descriptors for the thunk routines when using -m64.

I barely want to bother with this ;-).  So, no, I don't want to bother
with -m64 support.

- David

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Thu, 2011-10-13 at 10:03 -0700, Richard Henderson wrote:
 On 10/13/2011 08:49 AM, Peter Bergner wrote:
  + if (TARGET_LINK_STACK)
  +   asm_fprintf (file, \tbl 1f\n\tb 2f\n1:\n\tblr\n2:\n);
  + else
  +   asm_fprintf (file, \tbcl 20,31,1f\n1:\n);
 
 Wouldn't it be better to set up an out-of-line blr insn that could
 be shared by all instances?  That would solve a lot of this sort of
 this sort of branch-to-branch-to-branch ugliness.
 
 See the i386 port for an example of this, if you need it.

...after returning from a short vacation...

Ok, here's a patch to implement that, and it passes bootstrap and
regtesting.  Richard, is this what you had in mind?  I'll note that
I disabled rs6000_code_end for TARGET_POWERPC64, since I was running
into linker errors when building libgcc.  The merging of the thunk
routines with comdat worked fine, but the thunk function also has a
function descriptor and I couldn't figure out a way to get those
merged properly (if it's even possible), so they led to multiply
defined symbol linker errors.

Peter


* config.gcc (powerpc*-*-linux*): Add powerpc*-*-linux*ppc476* variant.
* config/rs6000/476.h: New file.
* config/rs6000/476.opt: Likewise.
* config/rs6000/rs6000.h (TARGET_LINK_STACK): New define.
(SET_TARGET_LINK_STACK): Likewise.
(TARGET_ASM_CODE_END): Define.
* config/rs6000/rs6000.c (rs6000_option_override_internal): Enable
TARGET_LINK_STACK for -mtune=476 and -mtune=476fp.
(rs6000_legitimize_tls_address): Emit the link stack preserving GOT
code if TARGET_LINK_STACK.
(rs6000_emit_load_toc_table): Likewise.
(output_function_profiler): Likewise
(macho_branch_islands): Likewise
(machopic_output_stub): Likewise
(get_ppc476_thunk_name): New function.
(rs6000_code_end): Likewise.
* config/rs6000/rs6000.md (load_toc_v4_PIC_1, load_toc_v4_PIC_1b):
Convert to a define_expand.
(load_toc_v4_PIC_1_normal): New define_insn.
(load_toc_v4_PIC_1_476): Likewise.
(load_toc_v4_PIC_1b_normal): Likewise.
(load_toc_v4_PIC_1b_476): Likewise.

Index: gcc/config.gcc
===
--- gcc/config.gcc  (revision 179091)
+++ gcc/config.gcc  (working copy)
@@ -2133,6 +2133,9 @@ powerpc-*-linux* | powerpc64-*-linux*)
esac
tmake_file=${tmake_file} t-slibgcc-libgcc
case ${target} in
+   powerpc*-*-linux*ppc476*)
+   tm_file=${tm_file} rs6000/476.h
+   extra_options=${extra_options} rs6000/476.opt ;;
powerpc*-*-linux*altivec*)
tm_file=${tm_file} rs6000/linuxaltivec.h ;;
powerpc*-*-linux*spe*)
Index: gcc/config/rs6000/476.h
===
--- gcc/config/rs6000/476.h (revision 0)
+++ gcc/config/rs6000/476.h (revision 0)
@@ -0,0 +1,32 @@
+/* Enable IBM PowerPC 476 support.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+   Contributed by Peter Bergner (berg...@vnet.ibm.com)
+   This file is part of GCC.
+
+   GCC 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.
+
+   GCC 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.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   http://www.gnu.org/licenses/.  */
+
+#undef TARGET_LINK_STACK
+#define TARGET_LINK_STACK (rs6000_link_stack)
+
+#undef SET_TARGET_LINK_STACK
+#define SET_TARGET_LINK_STACK(X) do { TARGET_LINK_STACK = (X); } while (0)
+
+#undef TARGET_ASM_CODE_END
+#define TARGET_ASM_CODE_END rs6000_code_end
Index: gcc/config/rs6000/rs6000-protos.h
===
--- gcc/config/rs6000/rs6000-protos.h   (revision 179091)
+++ gcc/config/rs6000/rs6000-protos.h   (working copy)
@@ -173,6 +173,7 @@ extern void rs6000_emit_eh_reg_restore (
 extern const char * output_isel (rtx *);
 extern void rs6000_call_indirect_aix (rtx, rtx, rtx);
 extern void rs6000_aix_asm_output_dwarf_table_ref (char *);
+extern void get_ppc476_thunk_name (char name[32]);
 
 /* Declare functions in rs6000-c.c */
 
Index: gcc/config/rs6000/476.opt

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Thu, 2011-10-27 at 20:43 -0500, Peter Bergner wrote:
 Index: gcc/config/rs6000/476.opt
[snip]
 +Target Var(rs6000_link_stack) Init(1) Save

Oops, this should actually be Init(-1).  The hunk above was just my
way of testing the modified code more by enabling it by default.
Sorry about that.

Peter

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Peter Bergner]

On Mon, 2011-09-12 at 15:29 -0400, David Edelsohn wrote:
 First, please choose a more informative option name.
 -mpreserve-link-stack seems like something generally useful for all
 processors and someone may randomly add the option.  It always is
 useful to preserve the link stack -- that's why you're jumping through
 hoops to fix this bug.  Maybe -mpreserve-ppc476-link-stack .

Done.


 I would prefer that this patch were maintained by the chip vendors
 distributing SDKs for PPC476 instead of complicating the FSF codebase.

Talking with the chip folks, they said there were a number of companies
already downloading the FSF gcc sources and building it unpatched and
that they expected more to do so in the future, so I'm not sure how many
(if any) are actually even relying on a SDK.  So...


 Otherwise, please implement this like Xilinx FPU in rs6000.opt,
 rs6000.h, ppc476.h and config.gcc where TARGET_LINK_STACK is defined
 as 0 unless GCC explicitly is configured for powerpc476.

Here's a patch to do that, by adding a variant to the powerpc*-*-linux*
target for the 476.  I bootstrapped and regtested this as before, meaning
I also tested this with the -mpreserve-ppc476-link-stack on by default,
as well as configuring without 476 support and verified that the
TARGET_LINK_STACK tests are not only optimized away, but so is the
-mpreserve-ppc476-link-stack option itself.

Is this ok for mainline now?

Peter


* config.gcc (powerpc*-*-linux*): Add powerpc*-*-linux*ppc476* variant.
* config/rs6000/476.h: New file.
* config/rs6000/476.opt: Likewise.
* config/rs6000/rs6000.h (TARGET_LINK_STACK): New define.
(SET_TARGET_LINK_STACK): Likewise.
* config/rs6000/rs6000.c (rs6000_option_override_internal): Enable
TARGET_LINK_STACK for -mtune=476 and -mtune=476fp.
(rs6000_legitimize_tls_address): Emit the link stack preserving GOT
code if TARGET_LINK_STACK.
(rs6000_emit_load_toc_table): Likewise.
(output_function_profiler): Likewise
(macho_branch_islands): Likewise
(machopic_output_stub): Likewise
* config/rs6000/rs6000.md (load_toc_v4_PIC_1, load_toc_v4_PIC_1b):
Convert to a define_expand.
(load_toc_v4_PIC_1_normal): New define_insn.
(load_toc_v4_PIC_1_476): Likewise.
(load_toc_v4_PIC_1b_normal): Likewise.
(load_toc_v4_PIC_1b_476): Likewise.


Index: gcc/config.gcc
===
--- gcc/config.gcc  (revision 179091)
+++ gcc/config.gcc  (working copy)
@@ -2133,6 +2133,9 @@ powerpc-*-linux* | powerpc64-*-linux*)
esac
tmake_file=${tmake_file} t-slibgcc-libgcc
case ${target} in
+   powerpc*-*-linux*ppc476*)
+   tm_file=${tm_file} rs6000/476.h
+   extra_options=${extra_options} rs6000/476.opt ;;
powerpc*-*-linux*altivec*)
tm_file=${tm_file} rs6000/linuxaltivec.h ;;
powerpc*-*-linux*spe*)
Index: gcc/config/rs6000/476.h
===
--- gcc/config/rs6000/476.h (revision 0)
+++ gcc/config/rs6000/476.h (revision 0)
@@ -0,0 +1,29 @@
+/* Enable IBM PowerPC 476 support.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+   Contributed by Peter Bergner (berg...@vnet.ibm.com)
+   This file is part of GCC.
+
+   GCC 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.
+
+   GCC 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.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   http://www.gnu.org/licenses/.  */
+
+#undef TARGET_LINK_STACK
+#define TARGET_LINK_STACK (rs6000_link_stack)
+
+#undef SET_TARGET_LINK_STACK
+#define SET_TARGET_LINK_STACK(X) do { TARGET_LINK_STACK = (X); } while (0)
Index: gcc/config/rs6000/476.opt
===
--- gcc/config/rs6000/476.opt   (revision 0)
+++ gcc/config/rs6000/476.opt   (revision 0)
@@ -0,0 +1,24 @@
+; IBM PowerPC 476 options.
+;
+; Copyright (C) 2011 Free Software Foundation, Inc.
+; Contributed by Peter Bergner (berg...@vnet.ibm.com)
+;
+; This file is part of GCC.
+;
+; GCC is free software; you can redistribute it and/or modify it under
+; the terms of the 

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[Richard Henderson]

On 10/13/2011 08:49 AM, Peter Bergner wrote:
 +   if (TARGET_LINK_STACK)
 + asm_fprintf (file, \tbl 1f\n\tb 2f\n1:\n\tblr\n2:\n);
 +   else
 + asm_fprintf (file, \tbcl 20,31,1f\n1:\n);

Wouldn't it be better to set up an out-of-line blr insn that could
be shared by all instances?  That would solve a lot of this sort of
this sort of branch-to-branch-to-branch ugliness.

See the i386 port for an example of this, if you need it.


r~

Re: [PATCH, rs6000] Preserve link stack for 476 cpus

[David Edelsohn]

On Mon, Sep 12, 2011 at 12:07 PM, Peter Bergner berg...@vnet.ibm.com wrote:
 The Power ISA declares the bcl 20,31,... instruction as the preferred
 idiom for obtaining the next instruction address (NIA), which we use for
 computing the address of the GOT.  This special branch and link is *not*
 a subroutine call, meaning it won't be paired with a blr (subroutine return).
 Processors therefore are not supposed to update their internal link stack
 when executing one of this instructions, otherwise we'll mispredict the
 following blrs.

 The 476 processor has an bug where it doesn't ignore these bcl 20,31,...
 instructions, so we end up getting lots of mispredicts for -fPIC code.
 The following patch adds a -mpreserve-link-stack option that is enabled
 automatically for -mtune={476,476fp}, that changes the two types of GOT
 access code GCC produces.  The new code replaces the bcl 20,31,... with
 a bl..., b..., blr triplet.  I've included some old versus new code
 snipits for both types of GOT access code to illustrate how the code
 has changed.


 1)      Normal Code:                            New 476 Code:
 ==

        bcl 20,31,$+4                           bl $+8
 .L3:                                    .L3:
                                                b $+8
                                                blr
        mflr 9                                  mflr 9
        addis 9,9,.LCTOC1-.L3@ha                addis 9,9,.LCTOC1-.L3@ha
        addi 9,9,.LCTOC1-.L3@l                  addi 9,9,.LCTOC1-.L3@l



 2)      Normal Code:                            New 476 Code:
 ==

        bcl 20,31,$+8                           bl $+12
        .long _GLOBAL_OFFSET_TABLE_-$           b $+12
                                                .long _GLOBAL_OFFSET_TABLE_-$
                                                blr
        mflr 9                                  mflr 9
                                                addi 9,9,4
        lwz 3,0(9)                              lwz 3,0(9)


 I have bootstrapped and regtested the following patch with no regressiosn.
 To test the code even more, I modified the patch so that we default to always
 using -mpreserve-link-stack and that bootstrapped and regtested with no
 regressions too.

 Ok for mainline?

 Peter


        * config/rs6000/rs6000.opt (mpreserve-link-stack): New option.
        * config/rs6000/rs6000.c (rs6000_option_override_internal): Enable
        TARGET_LINK_STACK for -mtune=476 and -mtune=476fp.
        (rs6000_legitimize_tls_address): Emit the link stack preserving GOT
        code if TARGET_LINK_STACK.
        (rs6000_emit_load_toc_table): Likewise.
        (output_function_profiler): Likewise
        (macho_branch_islands): Likewise
        (machopic_output_stub): Likewise
        * config/rs6000/rs6000.md (load_toc_v4_PIC_1, load_toc_v4_PIC_1b):
        Convert to a define_expand.
        (load_toc_v4_PIC_1_normal): New define_insn.
        (load_toc_v4_PIC_1_476): Likewise.
        (load_toc_v4_PIC_1b_normal): Likewise.
        (load_toc_v4_PIC_1b_476): Likewise.

First, please choose a more informative option name.
-mpreserve-link-stack seems like something generally useful for all
processors and someone may randomly add the option.  It always is
useful to preserve the link stack -- that's why you're jumping through
hoops to fix this bug.  Maybe -mpreserve-ppc476-link-stack .

I would prefer that this patch were maintained by the chip vendors
distributing SDKs for PPC476 instead of complicating the FSF codebase.

Otherwise, please implement this like Xilinx FPU in rs6000.opt,
rs6000.h, ppc476.h and config.gcc where TARGET_LINK_STACK is defined
as 0 unless GCC explicitly is configured for powerpc476.

Thanks, David