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Re: [PATCH] PR66870 PowerPC64 Enable gold linker with split stack


Thanks for doing this Alan.  I agree this looks better to me.

I assume by "etc" you mean you did biarch builds for your bootstraps on BE?

On 10/11/2015 08:07 AM, Alan Modra wrote:
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





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