Tue Mar 19 14:18:42 1996 Roland McGrath <roland@charlie-brown.gnu.ai.mit.edu>

	* config.make.in (weak-symbols): Variable removed.
	* configure.in (--with-weak-symbols): Option removed.
	(NO_UNDERSCORES, HAVE_ASM_WEAK_DIRECTIVE, HAVE_ASM_WEAKEXT_DIRECTIVE):
	New tests.
	* config.h.in (HAVE_WEAK_SYMBOLS): #undef removed.
	(NO_UNDERSCORES, HAVE_ASM_WEAK_DIRECTIVE, HAVE_ASM_WEAKEXT_DIRECTIVE):
	New #undefs.
	* libc-symbols.h: Use them instead of HAVE_WEAK_SYMBOLS.

diff --git a/config.h.in b/config.h.in
index 52332be..35d865b 100644 (file)
--- a/config.h.in
+++ b/config.h.in
@@ -4,12 +4,19 @@
 #undef HAVE_GNU_LD
 
 /* Define if using ELF, which supports weak symbols.
-   This implies HAVE_WEAK_SYMBOLS; set by --with-elf.  */
+   This implies HAVE_ASM_WEAK_DIRECTIVE and NO_UNDERSCORES; set by
+   --with-elf.  */
 #undef HAVE_ELF
 
-/* Define if weak symbols are available in the assembler and
-   linker being used.  Set by --with-weak-symbols.  */
-#undef HAVE_WEAK_SYMBOLS
+/* Define if C symbols are asm symbols.  Don't define if C symbols
+   have a `_' prepended to make the asm symbol.  */
+#undef NO_UNDERSCORES
+
+/* Define if weak symbols are available via the `.weak' directive.  */
+#undef HAVE_ASM_WEAK_DIRECTIVE
+
+/* Define if weak symbols are available via the `.weakext' directive.  */
+#undef HAVE_ASM_WEAKEXT_DIRECTIVE
 
 /* Define if not using ELF, but `.init' and `.fini' sections are available.  */
 #undef HAVE_INITFINI
@@ -24,13 +31,6 @@
    declaring a symbol global (default `.globl').  */
 #undef ASM_GLOBAL_DIRECTIVE
 
-/* ELF has weak symbols, and with GNU ld a.out does too.  */
-#ifndef HAVE_WEAK_SYMBOLS
-#if defined (HAVE_ELF) || defined (HAVE_GNU_LD)
-#define HAVE_WEAK_SYMBOLS
-#endif
-#endif
-
 /* Define to use GNU libio instead of GNU stdio.
    This is defined by configure under --enable-libio.  */
 #undef USE_IN_LIBIO

diff --git a/config.make.in b/config.make.in
index 2af925d..5057174 100644 (file)
--- a/config.make.in
+++ b/config.make.in
@@ -15,7 +15,6 @@ config-sysdirs = @sysnames@
 config-defines = @DEFS@
 
 elf = @elf@
-weak-symbols = @weak@
 have-initfini = @libc_cv_have_initfini@
 
 # Configuration options.

diff --git a/configure.in b/configure.in
index 4c9d881..d124e49 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1,6 +1,6 @@
 Dnl Process this file with autoconf to produce a configure script.
 AC_REVISION([$CVSid$])
-AC_PREREQ(2.4.2)dnl            dnl Minimum Autoconf version required.
+AC_PREREQ(2.9)dnl              dnl Minimum Autoconf version required.
 AC_INIT(features.h)
 AC_CONFIG_HEADER(config.h)
 
@@ -49,9 +49,6 @@ test $gnu_binutils = yes && gnu_as=yes gnu_ld=yes
 AC_ARG_WITH(elf, dnl
   --with-elf             if using the ELF object format,
            elf=$withval, elf=no)
-AC_ARG_WITH(weak-symbols, dnl
-  --with-weak-symbols    if weak symbols are available in as and ld,
-           weak=$withval, weak=no)
 
 AC_ARG_ENABLE(libio, dnl
 [  --enable-libio          build in GNU libio instead of GNU stdio],
@@ -406,6 +403,69 @@ if test $elf != yes; then
   fi
 fi
 
+if test $elf = yes; then
+  libc_cv_asm_underscores=no
+else
+  AC_CACHE_CHECK(for _ prefix on C symbol names, libc_cv_asm_underscores,
+                [AC_TRY_COMPILE([asm ("_glibc_foobar:");], [glibc_foobar ();],
+                                libc_cv_asm_underscores=yes,
+                                libc_cv_asm_underscores=no)])
+fi
+if test $libc_cv_asm_underscores = no; then
+  AC_DEFINE(NO_UNDERSCORES)
+fi
+
+if test $elf = yes; then
+  libc_cv_weak_symbols=yes
+  libc_cv_asm_weak_directive=yes
+  libc_cv_asm_weakext_directive=no
+else
+  AC_CACHE_CHECK(for assembler .weak directive, libc_cv_asm_weak_directive,
+                [dnl
+cat > conftest.s <<EOF
+.text
+${libc_cv_asm_global_directive} foo
+foo: .long 0
+.weak foo
+.weak bar; bar = foo
+EOF
+  if ${CC-cc} $CFLAGS -c conftest.s 2>/dev/null; then
+    libc_cv_asm_weak_directive=yes
+  else
+    libc_cv_asm_weak_directive=no
+  fi
+  rm -f conftest*])
+
+if $libc_cv_asm_weak_directive = no; then
+  AC_CACHE_CHECK(for assembler .weakext directive,
+                libc_cv_asm_weakext_directive,
+                [dnl
+cat > conftest.s <<EOF
+.text
+${libc_cv_asm_global_directive} foo
+foo: .long 0
+.weakext foo
+.weak bar, foo
+EOF
+  if ${CC-cc} $CFLAGS -c conftest.s 2>/dev/null; then
+    libc_cv_asm_weakext_directive=yes
+  else
+    libc_cv_asm_weakext_directive=no
+  fi
+  rm -f conftest*])
+
+  fi # no .weak
+fi # not ELF
+
+if test $libc_cv_asm_weak_directive; then
+  AC_DEFINE(HAVE_ASM_WEAK_DIRECTIVE)
+elif test $libc_cv_asm_weakext_directive; then
+  AC_DEFINE(HAVE_ASM_WEAKEXT_DIRECTIVE)
+fi
+
+### End of automated tests.
+### Now run sysdeps configure fragments.
+
 # sysdeps configure fragments may set these with files to be linked below.
 libc_link_dests=
 libc_link_sources=
@@ -498,7 +558,7 @@ default) stdio=stdio ;;
 esac
 AC_MSG_RESULT($stdio)
 
-AC_SUBST(gnu_ld) AC_SUBST(gnu_as) AC_SUBST(elf) AC_SUBST(weak)
+AC_SUBST(gnu_ld) AC_SUBST(gnu_as) AC_SUBST(elf)
 if test $gnu_ld = yes; then
   AC_DEFINE(HAVE_GNU_LD)
 fi
@@ -508,9 +568,6 @@ fi
 if test $elf = yes; then
   AC_DEFINE(HAVE_ELF)
 fi
-if test $weak = yes; then
-  AC_DEFINE(HAVE_WEAK_SYMBOLS)
-fi
 
 AC_SUBST(shared)
 if test $shared = default; then

diff --git a/libc-symbols.h b/libc-symbols.h
index bb5f54e..f7231f9 100644 (file)
--- a/libc-symbols.h
+++ b/libc-symbols.h
@@ -27,14 +27,13 @@ Cambridge, MA 02139, USA.  */
    We include config.h which is generated by configure.
    It should define for us the following symbols:
 
+   * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
+   * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'.
    * HAVE_GNU_LD if using GNU ld, with support for weak symbols in a.out,
    and for symbol set and warning messages extensions in a.out and ELF.
-   This implies HAVE_WEAK_SYMBOLS; set by --with-gnu-ld.
-   * HAVE_ELF if using ELF, which supports weak symbols.
-   This implies HAVE_WEAK_SYMBOLS; set by --with-elf.
-
-   * HAVE_WEAK_SYMBOLS if weak symbols are available in the assembler and
-   linker being used.  Set by --with-weak-symbols.
+   * HAVE_ELF if using ELF, which supports weak symbols using `.weak'.
+   * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
+   * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
 
    */
 
@@ -79,23 +78,14 @@ extern const char _libc_intl_domainname[];
 /*
 \f
 */
-/* The symbols in all the user (non-_) macros are C symbols.  Predefined
-   should be HAVE_WEAK_SYMBOLS and/or HAVE_ELF and/or HAVE_GNU_LD.
-   HAVE_WEAK_SYMBOLS is implied by the other two.  HAVE_GNU_LD without
-   HAVE_ELF implies a.out.  */
+/* The symbols in all the user (non-_) macros are C symbols.
+   HAVE_GNU_LD without HAVE_ELF implies a.out.  */
 
-#ifndef HAVE_WEAK_SYMBOLS
-#if defined (HAVE_ELF) || defined (HAVE_GNU_LD)
+#if defined (HAVE_ASM_WEAK_DIRECTIVE) || defined (HAVE_ASM_WEAKEXT_DIRECTIVE)
 #define HAVE_WEAK_SYMBOLS
 #endif
-#endif
 
 #ifndef __SYMBOL_PREFIX
-#ifdef HAVE_ELF
-#define NO_UNDERSCORES
-#else
-#include <sysdep.h>            /* Should define NO_UNDERSCORES.  */
-#endif
 #ifdef NO_UNDERSCORES
 #define __SYMBOL_PREFIX
 #else
@@ -143,8 +133,21 @@ extern const char _libc_intl_domainname[];
 
 
 #ifdef HAVE_WEAK_SYMBOLS
+
 #ifdef ASSEMBLER
 
+#ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
+
+/* Define ALIAS as a weak alias for ORIGINAL.
+   If weak aliases are not available, this defines a strong alias.  */
+#define weak_alias(original, alias)    \
+  .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
+
+/* Declare SYMBOL to be weak.  */
+#define weak_symbol(symbol)    .weakext C_SYMBOL_NAME (symbol)
+
+#else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
+
 /* Define ALIAS as a weak alias for ORIGINAL.
    If weak aliases are not available, this defines a strong alias.  */
 #define weak_alias(original, alias)    \
@@ -154,12 +157,21 @@ extern const char _libc_intl_domainname[];
 /* Declare SYMBOL to be weak.  */
 #define weak_symbol(symbol)    .weak C_SYMBOL_NAME (symbol)
 
-#else
+#endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
+
+#else /* ! ASSEMBLER */
+
+#ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
+#define weak_symbol(symbol)    asm (".weakext " __SYMBOL_PREFIX #symbol);
+#define weak_alias(original, alias) \
+  asm (".weakext " __SYMBOL_PREFIX #alias ", " __SYMBOL_PREFIX #original);
+#else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 #define weak_symbol(symbol)    asm (".weak " __SYMBOL_PREFIX #symbol);
 #define weak_alias(original, alias) \
   asm (".weak " __SYMBOL_PREFIX #alias "\n" \
        __SYMBOL_PREFIX #alias " = " __SYMBOL_PREFIX #original);
-#endif
+#endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
+#endif /* ! ASSEMBLER */
 #else
 #define        weak_alias(original, alias) strong_alias(original, alias)
 #define weak_symbol(symbol)    /* Do nothing.  */