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Re: [PATCH] PR66870 PowerPC64 Enable gold linker with split stack
- From: Alan Modra <amodra at gmail dot com>
- To: Ian Lance Taylor <iant at golang dot org>, David Edelsohn <dje dot gcc at gmail dot com>
- Cc: "Lynn A. Boger" <laboger at linux dot vnet dot ibm dot com>, Andreas Schwab <schwab at linux-m68k dot org>, Matthias Klose <doko at ubuntu dot com>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Sun, 11 Oct 2015 23:37:19 +1030
- Subject: Re: [PATCH] PR66870 PowerPC64 Enable gold linker with split stack
- Authentication-results: sourceware.org; auth=none
- References: <CAKOQZ8zQWx4oiok0FHDxOm7pX0StLJvhS5d=8YG4NM4Zrb8PDA at mail dot gmail dot com> <55FB10E7 dot 9090607 at linux dot vnet dot ibm dot com> <CAOyqgcVA_zhivM0+qRFk9bDT42Sot-HX95M1NtZjLVphZy_0vg at mail dot gmail dot com> <56101F0E dot 8000003 at ubuntu dot com> <56153C00 dot 2000209 at linux dot vnet dot ibm dot com> <561556F9 dot 8030802 at ubuntu dot com> <5616BC63 dot 3060307 at linux dot vnet dot ibm dot com> <5616D609 dot 2000400 at ubuntu dot com> <56181AD9 dot 6080501 at linux dot vnet dot ibm dot com> <87vbae2z71 dot fsf at igel dot home>
On Sat, Oct 10, 2015 at 11:25:38PM +0200, Andreas Schwab wrote:
> "Lynn A. Boger" <laboger@linux.vnet.ibm.com> writes:
>
> > Index: gcc/config/rs6000/sysv4.h
> > ===================================================================
> > --- gcc/config/rs6000/sysv4.h (revision 228653)
> > +++ gcc/config/rs6000/sysv4.h (working copy)
> > @@ -940,13 +940,15 @@ ncrtn.o%s"
> > #undef TARGET_ASAN_SHADOW_OFFSET
> > #define TARGET_ASAN_SHADOW_OFFSET rs6000_asan_shadow_offset
> >
> > -/* On ppc64 and ppc64le, split stack is only support for
> > - 64 bit. */
> > +/* On ppc64 and ppc64le, split stack is only supported for
> > + 64 bit targets with a 64 bit compiler. */
> > #undef TARGET_CAN_SPLIT_STACK_64BIT
> > +#if defined (__64BIT__) || defined (__powerpc64__) || defined (__ppc64__)
>
> This doesn't make sense. A target header cannot use host defines.
Right. Here's a better fix. A powerpc-linux biarch compiler can
default to either -m32 or -m64 so we need to take that into account,
and notice both -m32 and -m64 on the gccgo command line. It's also
possible to build a -m64 only compiler, so in that case we can define
TARGET_CAN_SPLIT_STACK.
Bootstrapped etc. powerpc64-linux, powerpc-linux and
powerpc64le-linux. OK?
gcc/
* config/rs6000/sysv4.h (TARGET_CAN_SPLIT_STACK_64BIT): Don't define.
* config/rs6000/linux64.h (TARGET_CAN_SPLIT_STACK): Define.
(TARGET_CAN_SPLIT_STACK_64BIT): Define.
gcc/go/
* gospec.c (saw_opt_m32): Rename to..
(is_m64): ..this, initialised by TARGET_CAN_SPLIT_STACK_64BIT.
Update uses.
(lang_specific_driver): Set is_m64 if OPT_m64, clear if OPT_m32.
diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
index 7b2f9bd..f48af43 100644
--- a/gcc/config/rs6000/sysv4.h
+++ b/gcc/config/rs6000/sysv4.h
@@ -940,14 +940,6 @@ ncrtn.o%s"
#undef TARGET_ASAN_SHADOW_OFFSET
#define TARGET_ASAN_SHADOW_OFFSET rs6000_asan_shadow_offset
-/* On ppc64 and ppc64le, split stack is only support for
- 64 bit. */
-#undef TARGET_CAN_SPLIT_STACK_64BIT
-#if TARGET_GLIBC_MAJOR > 2 \
- || (TARGET_GLIBC_MAJOR == 2 && TARGET_GLIBC_MINOR >= 18)
-#define TARGET_CAN_SPLIT_STACK_64BIT
-#endif
-
/* This target uses the sysv4.opt file. */
#define TARGET_USES_SYSV4_OPT 1
diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index 9599735..28c83e41 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -245,6 +245,21 @@ extern int dot_symbols;
#define MULTILIB_DEFAULTS { "m32" }
#endif
+/* Split stack is only supported for 64 bit, and requires glibc >= 2.18. */
+#if TARGET_GLIBC_MAJOR * 1000 + TARGET_GLIBC_MINOR >= 2018
+# ifndef RS6000_BI_ARCH
+# define TARGET_CAN_SPLIT_STACK
+# else
+# if DEFAULT_ARCH64_P
+/* Supported, and the default is -m64 */
+# define TARGET_CAN_SPLIT_STACK_64BIT 1
+# else
+/* Supported, and the default is -m32 */
+# define TARGET_CAN_SPLIT_STACK_64BIT 0
+# endif
+# endif
+#endif
+
#ifndef RS6000_BI_ARCH
/* 64-bit PowerPC Linux always has a TOC. */
diff --git a/gcc/go/gospec.c b/gcc/go/gospec.c
index ca3c2d7..fbb55be 100644
--- a/gcc/go/gospec.c
+++ b/gcc/go/gospec.c
@@ -120,8 +120,10 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
/* Whether the -S option was used. */
bool saw_opt_S = false;
- /* Whether the -m32 option was used. */
- bool saw_opt_m32 ATTRIBUTE_UNUSED = false;
+#ifdef TARGET_CAN_SPLIT_STACK_64BIT
+ /* Whether the -m64 option is in force. */
+ bool is_m64 = TARGET_CAN_SPLIT_STACK_64BIT;
+#endif
/* The first input file with an extension of .go. */
const char *first_go_file = NULL;
@@ -160,7 +162,11 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
#ifdef TARGET_CAN_SPLIT_STACK_64BIT
case OPT_m32:
- saw_opt_m32 = true;
+ is_m64 = false;
+ break;
+
+ case OPT_m64:
+ is_m64 = true;
break;
#endif
@@ -253,7 +259,7 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
#endif
#ifdef TARGET_CAN_SPLIT_STACK_64BIT
- if (!saw_opt_m32)
+ if (is_m64)
supports_split_stack = 1;
#endif
--
Alan Modra
Australia Development Lab, IBM