[committed] Revamp handling of initialization functions on hppa64-hpux

["John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>]

The enclosed patch changes the technique for handling initialization
functions such as __register_frame_info on hppa*64*-*-hpux*.  The
problem is that in HP land undefined weak symbols have to be defined
or else the dynamic loader refuses to run an application.  A secondary
problem is that a strong definition does not replace a previous weak
definition.  The HP linker will resolve a weak symbol using both
archive and shared libraries, while the GNU linker only resolves
weak symbols from shared libraries.

So, I've decided to remove '__attribute__ ((weak))' from
TARGET_ATTRIBUTE_WEAK and add an archive library of stub functions
that is linked in last after libgcc.  I've also removed the stub
definitions for __cxa_finalize and _Jv_RegisterClasses from the
crtbegin*.o objects as they couldn't be overloaded.

The patch also fixes a typo in LIB_SPEC (PR target/27034).

Tested on hppa64-hp-hpux11.11 with both GNU ld and HP ld.

Committed to trunk and 4.1.

Dave
-- 
J. David Anglin                                  dave.anglin@nrc-cnrc.gc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6602)

2006-04-09  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>

	PR target/27034
	PR target/26508
	* config.gcc (hppa*64*-*-hpux11*): Add 'libgcc_stub.a' to extra_parts.
	* pa64-hpux.h (LIB_SPEC): Correct typo.  Don't append milli.a.
	(LINK_GCC_C_SEQUENCE_SPEC): Define.  Append milli.a here.
	(PA_CXA_FINALIZE_STUB, PA_JV_REGISTERCLASSES_STUB): Delete defines.
	(PA_INIT_FINI_HACK): Rename to PA_CRTBEGIN_HACK.
	(PA_CRTBEGIN_HACK): Ensure __do_global_ctors_aux is placed in text
	section.  Delete PA_CXA_FINALIZE_STUB and PA_JV_REGISTERCLASSES_STUB
	stubs.  Add ".align 8" directives before all ".dword" directives.
	(GTHREAD_USE_WEAK): Revise comment.
	(TARGET_ATTRIBUTE_WEAK): Define.
	* pa/t-pa64 (LIBGCCSTUB_OBJS): Add new rules for stublib.c, rfi-stub.o,
	dfi-stub.o, cxaf-stub.o and jvrc-stub.o.
	* stublib.c: New file.

Index: config.gcc
===================================================================
--- config.gcc	(revision 112778)
+++ config.gcc	(working copy)
@@ -967,7 +967,8 @@
 	else
 	    tmake_file="$tmake_file pa/t-slibgcc-dwarf-ver"
 	fi
-	extra_parts="crtbegin.o crtend.o crtbeginS.o crtendS.o crtbeginT.o"
+	extra_parts="crtbegin.o crtend.o crtbeginS.o crtendS.o crtbeginT.o \
+		     libgcc_stub.a"
 	case x${enable_threads} in
 	xyes | xposix )
 		thread_file=posix 
Index: config/pa/pa64-hpux.h
===================================================================
--- config/pa/pa64-hpux.h	(revision 112778)
+++ config/pa/pa64-hpux.h	(working copy)
@@ -63,22 +63,26 @@
 	   %{static:%{!nolibdld:-a shared -ldld -a archive -lc}}}}\
      %{pg:%{static:%{!mhp-ld:-a shared}%{mhp-ld:-a archive_shared}}\
        -lgprof %{static:-a archive} %{static|mt|pthread:-lpthread} -lc\
-       %{static:%{!nolibdld:-a shared -ldld -a archive -lc}}}}\
-   /usr/lib/pa20_64/milli.a"
+       %{static:%{!nolibdld:-a shared -ldld -a archive -lc}}}}"
 #else
 #define LIB_SPEC \
   "%{!shared:\
      %{!p:%{!pg: %{static|mt|pthread:-lpthread} -lc\
 	    %{static:%{!nolibdld:-a shared -ldld -a archive -lc}}}}\
      %{p:%{!pg:%{static:%{mgnu-ld:-a shared}%{!mgnu-ld:-a archive_shared}}\
-	   -lprof %{static:-a archive} %{shatic|mt|pthread:-lpthread} -lc\
+	   -lprof %{static:-a archive} %{static|mt|pthread:-lpthread} -lc\
 	   %{static:%{!nolibdld:-a shared -ldld -a archive -lc}}}}\
      %{pg:%{static:%{mgnu-ld:-a shared}%{!mgnu-ld:-a archive_shared}}\
        -lgprof %{static:-a archive} %{static|mt|pthread:-lpthread} -lc\
-       %{static:%{!nolibdld:-a shared -ldld -a archive -lc}}}}\
-   /usr/lib/pa20_64/milli.a"
+       %{static:%{!nolibdld:-a shared -ldld -a archive -lc}}}}"
 #endif
 
+/* The libgcc_stub.a and milli.a libraries need to come last.  */
+#undef LINK_GCC_C_SEQUENCE_SPEC
+#define LINK_GCC_C_SEQUENCE_SPEC "\
+  %G %L %G %{!nostdlib:%{!nodefaultlibs:%{!shared:-lgcc_stub}\
+  /usr/lib/pa20_64/milli.a}}"
+
 /* Under hpux11, the normal location of the `ld' and `as' programs is the
    /usr/ccs/bin directory.  */
 
@@ -326,16 +330,7 @@
    the array.  DT_FINI_ARRAY is supposed to be executed in the opposite
    order.
 
-   The second hack is stubs for __cxa_finalize and _Jv_RegisterClasses.
-   The HP implementation of undefined weak symbols is broken.  The linker
-   and dynamic loader both search for undefined weak symbols contrary the
-   generic System V ABI.  An undefined weak symbol should resolve to a
-   value of 0 rather than causing an error.  The prototypes for
-   __cxa_finalize and _Jv_RegisterClasses in crtstuff.c are weak when
-   weak is supported (GNU as), so in theory a strong define should override
-   the stub functions provided here.
-
-   The final hack is a set of plabels to implement the effect of
+   The second hack is a set of plabels to implement the effect of
    CRT_CALL_STATIC_FUNCTION.  HP-UX 11 only supports DI_INIT_ARRAY and
    DT_FINI_ARRAY and they put the arrays in .init and .fini, rather than
    in .init_array and .fini_array.  The standard defines for .init and
@@ -351,25 +346,6 @@
    either using the linker +init command or a plabel, run before the
    initializers specified here.  */
 
-/* We need a __cxa_finalize stub if CRTSTUFFS_O is defined.  */
-#ifdef CRTSTUFFS_O
-#define PA_CXA_FINALIZE_STUB \
-extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;		\
-void									\
-__cxa_finalize (void *p __attribute__((unused))) {}
-#else
-#define PA_CXA_FINALIZE_STUB
-#endif
-
-/* We need a _Jv_RegisterClasses stub if JCR_SECTION_NAME is defined.  */
-#ifdef JCR_SECTION_NAME
-#define PA_JV_REGISTERCLASSES_STUB \
-void									\
-_Jv_RegisterClasses (void *p __attribute__((unused))) {}
-#else
-#define PA_JV_REGISTERCLASSES_STUB
-#endif
-
 /* We need to add frame_dummy to the initializer list if EH_FRAME_SECTION_NAME
    or JCR_SECTION_NAME is defined.  */
 #if defined(EH_FRAME_SECTION_NAME) || defined(JCR_SECTION_NAME)
@@ -378,7 +354,10 @@
 #define PA_INIT_FRAME_DUMMY_ASM_OP ""
 #endif
 
-#define PA_INIT_FINI_HACK \
+/* The following hack sets up the .init, .init_array, .fini and
+   .fini_array sections.  */
+#define PA_CRTBEGIN_HACK \
+asm (TEXT_SECTION_ASM_OP);						\
 static void __attribute__((used))					\
 __do_global_ctors_aux (void)						\
 {									\
@@ -389,35 +368,36 @@
     (*p) ();								\
 }									\
 									\
-PA_CXA_FINALIZE_STUB							\
-PA_JV_REGISTERCLASSES_STUB						\
-									\
 asm (HP_INIT_ARRAY_SECTION_ASM_OP);					\
+asm (".align 8");							\
 asm (".dword P%__do_global_ctors_aux");					\
 asm (PA_INIT_FRAME_DUMMY_ASM_OP);					\
 asm (GNU_INIT_ARRAY_SECTION_ASM_OP);					\
+asm (".align 8");							\
 asm (".dword P%__do_global_ctors_aux");					\
 asm (PA_INIT_FRAME_DUMMY_ASM_OP);					\
 asm (HP_FINI_ARRAY_SECTION_ASM_OP);					\
+asm (".align 8");							\
 asm (".dword P%__do_global_dtors_aux");					\
 asm (GNU_FINI_ARRAY_SECTION_ASM_OP);					\
+asm (".align 8");							\
 asm (".dword P%__do_global_dtors_aux")
 
 /* The following two variants of DTOR_LIST_BEGIN are identical to those
-   in crtstuff.c except for the addition of the above init-fini hack.  */
+   in crtstuff.c except for the addition of the above crtbegin hack.  */
 #ifdef DTORS_SECTION_ASM_OP
 #define DTOR_LIST_BEGIN \
 asm (DTORS_SECTION_ASM_OP);						\
 STATIC func_ptr __DTOR_LIST__[1]					\
   __attribute__ ((aligned(sizeof(func_ptr))))				\
   = { (func_ptr) (-1) };						\
-PA_INIT_FINI_HACK
+PA_CRTBEGIN_HACK
 #else
 #define DTOR_LIST_BEGIN \
 STATIC func_ptr __DTOR_LIST__[1]					\
   __attribute__ ((section(".dtors"), aligned(sizeof(func_ptr))))	\
   = { (func_ptr) (-1) };						\
-PA_INIT_FINI_HACK
+PA_CRTBEGIN_HACK
 #endif
 
 /* If using HP ld do not call pxdb.  Use size as a program that does nothing
@@ -425,6 +405,15 @@
    an interpreter.  */
 #define INIT_ENVIRONMENT "LD_PXDB=/usr/ccs/bin/size"
 
-/* The HPUX dynamic linker objects to weak symbols with no
-   definitions, so do not use them in gthr-posix.h.  */
+/* The HPUX dynamic linker objects to undefined weak symbols, so do
+   not use them in gthr-posix.h.  */
 #define GTHREAD_USE_WEAK 0
+
+/* We don't want undefined weak references to __register_frame_info,
+   __deregister_frame_info, _Jv_RegisterClasses and __cxa_finalize
+   introduced by crtbegin.o.  The GNU linker only resolves weak
+   references if they appear in a shared library.  Thus, it would be
+   impossible to create a static executable if the symbols were weak.
+   So, the best solution seems to be to make the symbols strong and
+   provide an archive library of empty stub functions.  */
+#define TARGET_ATTRIBUTE_WEAK
Index: config/pa/t-pa64
===================================================================
--- config/pa/t-pa64	(revision 112778)
+++ config/pa/t-pa64	(working copy)
@@ -1,2 +1,28 @@
-TARGET_LIBGCC2_CFLAGS = -fPIC -Dpa64=1 -DELF=1 -mlong-calls
-LIB2FUNCS_EXTRA=quadlib.c
+TARGET_LIBGCC2_CFLAGS = -fPIC -Dpa64=1 -DELF=1 -mlong-calls
+LIB2FUNCS_EXTRA = quadlib.c
+LIBGCCSTUB_OBJS = rfi-stub.o dfi-stub.o jvrc-stub.o cxaf-stub.o
+
+stublib.c: $(srcdir)/config/pa/stublib.c
+	rm -f stublib.c
+	cp $(srcdir)/config/pa/stublib.c .
+
+rfi-stub.o: stublib.c
+	$(GCC_FOR_TARGET) -c -O2 -DL_register_frame_info stublib.c \
+	  -o rfi-stub.o
+
+dfi-stub.o: stublib.c
+	$(GCC_FOR_TARGET) -c -O2 -DL_deregister_frame_info stublib.c \
+	  -o dfi-stub.o
+
+cxaf-stub.o: stublib.c
+	$(GCC_FOR_TARGET) -c -O2 -DL_cxa_finalize stublib.c \
+	  -o cxaf-stub.o
+
+jvrc-stub.o: stublib.c
+	$(GCC_FOR_TARGET) -c -O2 -DL_Jv_RegisterClasses stublib.c \
+	  -o jvrc-stub.o
+
+libgcc_stub.a: $(LIBGCCSTUB_OBJS)
+	-rm -rf libgcc_stub.a
+	$(AR) rc libgcc_stub.a $(LIBGCCSTUB_OBJS)
+	$(RANLIB) libgcc_stub.a
--- /dev/null	Sun Apr  2 16:48:13 2006
+++ config/pa/stublib.c	Sun Apr  2 15:56:37 2006
@@ -0,0 +1,63 @@
+/* Stub functions.
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+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 2, or (at your option)
+any later version.
+
+In addition to the permissions in the GNU General Public License, the
+Free Software Foundation gives you unlimited permission to link the
+compiled version of this file into combinations with other programs,
+and to distribute those combinations without any restriction coming
+from the use of this file.  (The General Public License restrictions
+do apply in other respects; for example, they cover modification of
+the file, and distribution when not linked into a combine
+executable.)
+
+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.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING.  If not, write to
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
+
+#ifdef L_register_frame_info
+struct object;
+void  __register_frame_info (const void * __attribute__((unused)),
+			     struct object * __attribute__((unused)));
+void
+__register_frame_info (const void *p, struct object *ob)
+{
+}
+#endif
+
+#ifdef L_deregister_frame_info
+void *__deregister_frame_info (const void * __attribute__((unused)));
+void *
+__deregister_frame_info (const void *p)
+{
+  return (void *)0;
+}
+#endif
+
+#ifdef L_cxa_finalize
+void __cxa_finalize (void * __attribute__((unused)));
+void
+__cxa_finalize (void *p)
+{
+}
+#endif
+
+#ifdef L_Jv_RegisterClasses
+void _Jv_RegisterClasses (void * __attribute__((unused)));
+void
+_Jv_RegisterClasses (void *p)
+{
+}
+#endif