configure.in: Disable collect2 for nextstep.

        * configure.in: Disable collect2 for nextstep.  Instead use
        crtbegin/crtend.
        * configure: Rebuilt.
        * config/nextstep.h (STARTFILE_SPEC): Add crtbegin.
        (ENDFILE_SPEC): Define.
        (OBJECT_FORMAT_MACHO): Define.
        (EH_FRAME_SECTION_ASM_OP): Define.
        * crtstuff.c: Handle MACHO.

From-SVN: r22487

gcc/ChangeLog

+Sat Sep 19 23:58:07 1998  Melissa O'Neill <oneill@cs.sfu.ca>
+			 
+	* configure.in: Disable collect2 for nextstep.  Instead use
+	crtbegin/crtend.
+	* configure: Rebuilt.
+	* config/nextstep.h (STARTFILE_SPEC): Add crtbegin.
+	(ENDFILE_SPEC): Define.
+	(OBJECT_FORMAT_MACHO): Define.
+	(EH_FRAME_SECTION_ASM_OP): Define.
+	* crtstuff.c: Handle MACHO.
+
 Sun Sep 20 00:24:24 1998  Robert Lipe  <robertl@dgii.com>
 
 	* config/i386/sco5.h (TARGET_MEM_FUNCTIONS):  Define.

gcc/config/nextstep.h

@@ -167,7 +167,12 @@ Boston, MA 02111-1307, USA.  */
      %{!p:-lcrt0.o}}}\
      %{posix*:%{pg:-lgposixcrt0.o}%{!pg: \
      %{p:%e-p profiling is no longer supported.  Use -pg instead.} \
-     %{!p:-lposixcrt0.o}}}"
+     %{!p:-lposixcrt0.o}}} \
+     -lcrtbegin.o"
+
+#undef	ENDFILE_SPEC
+#define ENDFILE_SPEC \
+    "-lcrtend.o"
 
 /* Allow #sscs (but don't do anything). */
 
@@ -203,6 +208,9 @@ Boston, MA 02111-1307, USA.  */
 	   "\t.text\n\t.stabs \"%s\",%d,0,0,Letext\nLetext:\n",		\
 	   "" , N_SO)
 
+/* Define our object format type for crtstuff.c */
+#define OBJECT_FORMAT_MACHO
+
 /* Don't use .gcc_compiled symbols to communicate with GDB;
    They interfere with numerically sorted symbol lists. */
 
@@ -232,6 +240,8 @@ Boston, MA 02111-1307, USA.  */
        fprintf (FILE, ".reference .destructors_used\n");        \
       } while (0)
 
+#define EH_FRAME_SECTION_ASM_OP ".section __TEXT,__eh_frame,regular"
+
 /* Don't output a .file directive.  That is only used by the assembler for
    error reporting.  */
 #undef	ASM_FILE_START

gcc/configure.in

@@ -899,7 +899,7 @@ changequote([,])dnl
 		tmake_file=i386/t-next
 		xmake_file=i386/x-next
 		extra_objs=nextstep.o
-		use_collect2=yes
+		extra_parts="crtbegin.o crtend.o"
  		if test x$enable_threads = xyes; then
 			thread_file='mach'
 		fi
@@ -1777,8 +1777,8 @@ changequote([,])dnl
 		tmake_file=m68k/t-next
 		xmake_file=m68k/x-next
 		extra_objs=nextstep.o
+		extra_parts="crtbegin.o crtend.o"
 		extra_headers=math-68881.h
-		use_collect2=yes
 		float_format=m68k
  		if test x$enable_threads = xyes; then
 			thread_file='mach'

gcc/crtstuff.c

@@ -56,6 +56,8 @@ Boston, MA 02111-1307, USA.  */
 #include <stddef.h>
 #include "frame.h"
 
+#ifndef OBJECT_FORMAT_MACHO
+
 /* Provide default definitions for the pseudo-ops used to switch to the
    .ctors and .dtors sections.
  
@@ -458,3 +460,71 @@ STATIC ui32 __FRAME_END__[] __attribute__ ((__unused__)) = { 0 };
 #endif /* EH_FRAME_SECTION */
 
 #endif /* defined(CRT_END) */
+
+#else  /* OBJECT_FORMAT_MACHO */
+
+/* For Mach-O format executables, we assume that the system's runtime is
+   smart enough to handle constructors and destructors, but doesn't have
+   an init section (if it can't even handle constructors/destructors
+   you should be using INVOKE__main, not crtstuff). All we need to do
+   is install/deinstall the frame information for exceptions. We do this
+   by putting a constructor in crtbegin.o and a destructor in crtend.o.
+
+   crtend.o also puts in the terminating zero in the frame information
+   segment. */
+
+/* The crtstuff for other object formats use the symbol __EH_FRAME_BEGIN__
+   to figure out the start of the exception frame, but here we use
+   getsectbynamefromheader to find this value. Either method would work,
+   but this method avoids creating any global symbols, which seems
+   cleaner. */
+
+#include <mach-o/ldsyms.h>
+extern const struct section *
+  getsectbynamefromheader (const struct mach_header *,
+			   const char *, const char *);
+
+#ifdef CRT_BEGIN
+
+static void __reg_frame_ctor () __attribute__ ((constructor));
+
+static void
+__reg_frame_ctor ()
+{
+  static struct object object;
+  const struct section *eh_frame;
+
+  eh_frame = getsectbynamefromheader (&_mh_execute_header,
+				      "__TEXT", "__eh_frame");
+  __register_frame_info ((void *) eh_frame->addr, &object);
+}
+
+#endif /* CRT_BEGIN */
+
+#ifdef CRT_END
+
+static void __dereg_frame_dtor () __attribute__ ((destructor));
+
+static
+void __dereg_frame_dtor ()
+{
+  const struct section *eh_frame;
+
+  eh_frame = getsectbynamefromheader (&_mh_execute_header,
+				      "__TEXT", "__eh_frame");
+  __deregister_frame_info ((void *) eh_frame->addr);
+}
+
+/* Terminate the frame section with a final zero. */
+
+/* Force cc1 to switch to .data section.  */
+static void * force_to_data[0] __attribute__ ((__unused__)) = { };
+
+typedef unsigned int ui32 __attribute__ ((mode (SI)));
+asm (EH_FRAME_SECTION_ASM_OP);
+static ui32 __FRAME_END__[] __attribute__ ((__unused__)) = { 0 };
+
+#endif /* CRT_END */
+
+#endif /* OBJECT_FORMAT_MACHO */
+