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More Solaris 2 ABI fixes: emit local _START_, _END_

Rainer Orth ro@CeBiTec.Uni-Bielefeld.DE
Tue Oct 12 17:17:00 GMT 2010 
Richard Henderson <rth@redhat.com> writes:

> On 09/27/2010 10:11 AM, Rainer Orth wrote:
>> TEXT_START_SYMBOLS='_START_ = .;'
>> OTHER_END_SYMBOLS='_END_ = .;'
>
> Create global symbols like this code does, but ...
>
>> My next attempt was to achieve this directly in ld/emultempl/solaris2.em
>> with C code: I tried all of gld${EMULATION_NAME}_before_allocation,
>> _after_allocation, and _finish with a snippet like this
>
> ... do it here, then mark them STV_HIDDEN.

Thanks for the hint.  This worked, although I'm setting forced_local to
1; whether or not I added STV_HIDDEN made no difference.  There's one
minor problem, though: if generating a shared object, _START_ and _END_
are emitted into .dynsym, unlike what Sun ld does.  I've tried to set
h->dynamic to 0, but that had no effect.

Anyway, that's the patch I currently have.  I've combined it with

	More Solaris 2 ABI fixes: emit _DYNAMIC etc. into .dynsym
	http://sourceware.org/ml/binutils/2010-09/msg00482.html

(already approved by Alan) since I'm renaming abi_syms to global_syms
for clarity.

Ok for mainline?

	Rainer


2010-09-25  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	* emultempl/solaris2.em (elf_solaris2_before_allocation): Renamed
	basever_syms to global_syms.
	Emit global_syms into .dynamic section for all executables and
	shared objects.
	(elf_solaris2_after_allocation): New function.
	(LDEMUL_AFTER_ALLOCATION): Use it.
	* emulparams/solaris2.sh: New file.
	* emulparams/elf32_sparc_sol2.sh: Use it.
	* emulparams/elf64_sparc_sol2.sh: Likewise.
	* emulparams/elf_i386_sol2.sh: Likewise.
	* emulparams/elf_x86_64_sol2.sh: Likewise.
	* Makefile.am (eelf32_sparc_sol2.c): Depend on
	$(srcdir)/emulparams/solaris2.sh.
	(eelf64_sparc_sol2.c): Likewise.
	(eelf_x86_64_sol2.c): Likewise.
	(eelf_i386_sol2.c): Likewise.
	* Makefile.in: Regenerate.

Index: ld/Makefile.am
===================================================================
RCS file: /vol/gnu/src/binutils/src-cvs/src/ld/Makefile.am,v
retrieving revision 1.288
diff -u -p -r1.288 Makefile.am
--- ld/Makefile.am	20 Aug 2010 21:18:39 -0000	1.288
+++ ld/Makefile.am	25 Sep 2010 20:40:59 -0000
@@ -853,6 +853,7 @@ eelf32_sparc.c: $(srcdir)/emulparams/elf
 	${GENSCRIPTS} elf32_sparc "$(tdir_elf32_sparc)"
 eelf32_sparc_sol2.c: $(srcdir)/emulparams/elf32_sparc_sol2.sh \
   $(srcdir)/emulparams/elf32_sparc.sh \
+  $(srcdir)/emulparams/solaris2.sh \
   $(srcdir)/emultempl/solaris2.em $(ELF_DEPS) \
   $(srcdir)/scripttempl/elf.sc ${GEN_DEPENDS}
 	${GENSCRIPTS} elf32_sparc_sol2 "$(tdir_elf32_sparc_sol2)"
@@ -1111,6 +1112,7 @@ eelf64_sparc_fbsd.c: $(srcdir)/emulparam
 	${GENSCRIPTS} elf64_sparc_fbsd "$(tdir_elf64_sparc_fbsd)"
 eelf64_sparc_sol2.c: $(srcdir)/emulparams/elf64_sparc_sol2.sh \
   $(srcdir)/emulparams/elf64_sparc.sh \
+  $(srcdir)/emulparams/solaris2.sh \
   $(srcdir)/emultempl/solaris2.em \
   $(ELF_DEPS) $(srcdir)/scripttempl/elf.sc ${GEN_DEPENDS}
 	${GENSCRIPTS} elf64_sparc_sol2 "$(tdir_elf64_sparc_sol2)"
@@ -1151,6 +1153,7 @@ eelf_x86_64_fbsd.c: $(srcdir)/emulparams
 	${GENSCRIPTS} elf_x86_64_fbsd "$(tdir_elf_x86_64_fbsd)"
 eelf_x86_64_sol2.c: $(srcdir)/emulparams/elf_x86_64_sol2.sh \
   $(srcdir)/emulparams/elf_x86_64.sh \
+  $(srcdir)/emulparams/solaris2.sh \
   $(srcdir)/emultempl/solaris2.em \
   $(ELF_DEPS) $(srcdir)/scripttempl/elf.sc ${GEN_DEPENDS}
 	${GENSCRIPTS} elf_x86_64_sol2 "$(tdir_elf_x86_64_sol2)"
@@ -1175,6 +1178,7 @@ eelf_i386_ldso.c: $(srcdir)/emulparams/e
   $(ELF_DEPS) $(srcdir)/scripttempl/elf.sc ${GEN_DEPENDS}
 	${GENSCRIPTS} elf_i386_ldso "$(tdir_elf_i386_ldso)"
 eelf_i386_sol2.c: $(srcdir)/emulparams/elf_i386_sol2.sh \
+  $(srcdir)/emulparams/solaris2.sh \
   $(srcdir)/emultempl/solaris2.em \
   $(ELF_DEPS) $(srcdir)/scripttempl/elf.sc ${GEN_DEPENDS}
 	${GENSCRIPTS} elf_i386_sol2 "$(tdir_elf_i386_sol2)"
Index: ld/emulparams/elf32_sparc_sol2.sh
===================================================================
RCS file: /vol/gnu/src/binutils/src-cvs/src/ld/emulparams/elf32_sparc_sol2.sh,v
retrieving revision 1.1
diff -u -p -r1.1 elf32_sparc_sol2.sh
--- ld/emulparams/elf32_sparc_sol2.sh	17 Mar 2010 08:46:49 -0000	1.1
+++ ld/emulparams/elf32_sparc_sol2.sh	25 Sep 2010 20:17:31 -0000
@@ -1,2 +1,3 @@
 . ${srcdir}/emulparams/elf32_sparc.sh
+. ${srcdir}/emulparams/solaris2.sh
 EXTRA_EM_FILE=solaris2
Index: ld/emulparams/elf64_sparc_sol2.sh
===================================================================
RCS file: /vol/gnu/src/binutils/src-cvs/src/ld/emulparams/elf64_sparc_sol2.sh,v
retrieving revision 1.1
diff -u -p -r1.1 elf64_sparc_sol2.sh
--- ld/emulparams/elf64_sparc_sol2.sh	17 Mar 2010 08:46:49 -0000	1.1
+++ ld/emulparams/elf64_sparc_sol2.sh	25 Sep 2010 20:17:57 -0000
@@ -1,2 +1,3 @@
 . ${srcdir}/emulparams/elf64_sparc.sh
+. ${srcdir}/emulparams/solaris2.sh
 EXTRA_EM_FILE=solaris2
Index: ld/emulparams/elf_i386_sol2.sh
===================================================================
RCS file: /vol/gnu/src/binutils/src-cvs/src/ld/emulparams/elf_i386_sol2.sh,v
retrieving revision 1.1
diff -u -p -r1.1 elf_i386_sol2.sh
--- ld/emulparams/elf_i386_sol2.sh	5 Mar 2010 19:48:59 -0000	1.1
+++ ld/emulparams/elf_i386_sol2.sh	25 Sep 2010 20:18:39 -0000
@@ -1,3 +1,4 @@
 . ${srcdir}/emulparams/elf_i386_ldso.sh
+. ${srcdir}/emulparams/solaris2.sh
 EXTRA_EM_FILE=solaris2
 OUTPUT_FORMAT="elf32-i386-sol2"
Index: ld/emulparams/elf_x86_64_sol2.sh
===================================================================
RCS file: /vol/gnu/src/binutils/src-cvs/src/ld/emulparams/elf_x86_64_sol2.sh,v
retrieving revision 1.1
diff -u -p -r1.1 elf_x86_64_sol2.sh
--- ld/emulparams/elf_x86_64_sol2.sh	5 Mar 2010 19:48:59 -0000	1.1
+++ ld/emulparams/elf_x86_64_sol2.sh	25 Sep 2010 20:19:04 -0000
@@ -1,3 +1,4 @@
 . ${srcdir}/emulparams/elf_x86_64.sh
+. ${srcdir}/emulparams/solaris2.sh
 EXTRA_EM_FILE=solaris2
 OUTPUT_FORMAT="elf64-x86-64-sol2"
Index: ld/emulparams/solaris2.sh
===================================================================
RCS file: ld/emulparams/solaris2.sh
diff -N ld/emulparams/solaris2.sh
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ ld/emulparams/solaris2.sh	3 Oct 2010 22:11:00 -0000
@@ -0,0 +1,10 @@
+# If you change this file, please also look at files which source this one:
+# elf32_sparc_sol2.sh, elf64_sparc_sol2.sh, elf_i386_sol2.sh,
+# elf_x86_64_sol2.sh.
+
+# The Solaris 2 ABI requires that two local symbols are present in every
+# executable and shared object.
+# Cf. Linker and Libraries Guide, Ch. 2, Link-Editor, Generating the Output
+# File, p.63.
+TEXT_START_SYMBOLS='_START_ = .;'
+OTHER_END_SYMBOLS='_END_ = .;'
Index: ld/emultempl/solaris2.em
===================================================================
RCS file: /vol/gnu/src/binutils/src-cvs/src/ld/emultempl/solaris2.em,v
retrieving revision 1.1
diff -u -p -r1.1 solaris2.em
--- ld/emultempl/solaris2.em	5 Mar 2010 19:49:00 -0000	1.1
+++ ld/emultempl/solaris2.em	12 Oct 2010 17:05:51 -0000
@@ -31,16 +31,17 @@ fragment <<EOF
 
 #define TARGET_IS_${EMULATION_NAME}
 
-/* The Solaris 2 ABI requires some symbols to always be bound to the base
-   version in a shared object.
+/* The Solaris 2 ABI requires some global symbols to be present in the
+   .dynsym table of executables and shared objects.  If generating a
+   versioned shared object, they must always be bound to the base version.
 
    Cf. Linker and Libraries Guide, Ch. 2, Link-Editor, Generating the Output
    File, p.63.  */
 static void
 elf_solaris2_before_allocation (void)
 {
-  /* Symbols required to be bound to the base version.  */
-  static const char *basever_syms[] = {
+  /* Global symbols required by the Solaris 2 ABI.  */
+  static const char *global_syms[] = {
     "_DYNAMIC",
     "_GLOBAL_OFFSET_TABLE_",
     "_PROCEDURE_LINKAGE_TABLE_",
@@ -51,6 +52,28 @@ elf_solaris2_before_allocation (void)
   };
   const char **sym;
 
+  /* Do this for both executables and shared objects.  */
+  if (!link_info.relocatable)
+    {
+      for (sym = global_syms; *sym != NULL; sym++)
+	{
+	  struct elf_link_hash_entry *h;
+
+	  /* Lookup symbol.  */
+	  h = elf_link_hash_lookup (elf_hash_table (&link_info), *sym,
+				    FALSE, FALSE, FALSE);
+	  if (h == NULL)
+	    continue;
+
+	  /* Undo the hiding done by _bfd_elf_define_linkage_sym.  */
+	  h->forced_local = 0;
+	  h->other &= ~STV_HIDDEN;
+
+	  /* Emit it into the .dynamic section, too.  */
+	  bfd_elf_link_record_dynamic_symbol (&link_info, h);
+	}
+    }
+
   /* Only do this if emitting a shared object and versioning is in place. */
   if (link_info.shared
       && (lang_elf_version_info != NULL || link_info.create_default_symver))
@@ -59,7 +82,7 @@ elf_solaris2_before_allocation (void)
       struct bfd_elf_version_tree *basever;
       const char *soname;
 
-      for (sym = basever_syms; *sym != NULL; sym++)
+      for (sym = global_syms; *sym != NULL; sym++)
 	{
 	  /* Create a version pattern for this symbol.  Some of them start
 	     off as local, others as global, so try both.  */
@@ -80,8 +103,32 @@ elf_solaris2_before_allocation (void)
       lang_register_vers_node (soname, basever, NULL);
       /* Enforce base version.  The encoded vd_ndx is vernum + 1.  */
       basever->vernum = 0;
+    }
 
-      for (sym = basever_syms; *sym != NULL; sym++)
+  gld${EMULATION_NAME}_before_allocation ();
+}
+
+/* The Solaris 2 ABI requires two local symbols to be emitted for every
+   executable and shared object.
+
+   Cf. Linker and Libraries Guide, Ch. 2, Link-Editor, Generating the Output
+   File, p.63.  */
+static void
+elf_solaris2_after_allocation (void)
+{
+  /* Local symbols required by the Solaris 2 ABI.  Already emitted by
+     emulparams/solaris2.sh.  */
+  static const char *local_syms[] = {
+    "_START_",
+    "_END_",
+    NULL
+  };
+  const char **sym;
+
+  /* Do this for both executables and shared objects.  */
+  if (!link_info.relocatable)
+    {
+      for (sym = local_syms; *sym != NULL; sym++)
 	{
 	  struct elf_link_hash_entry *h;
 
@@ -91,18 +138,17 @@ elf_solaris2_before_allocation (void)
 	  if (h == NULL)
 	    continue;
 
-	  /* Undo the hiding done by _bfd_elf_define_linkage_sym.  */
-	  h->forced_local = 0;
-	  h->other &= ~STV_HIDDEN;
-
-	  /* Emit it into the .dynamic section, too.  */
-	  bfd_elf_link_record_dynamic_symbol (&link_info, h);
+	  /* Turn it local.  */
+	  h->forced_local = 1;
+	  /* Type should be STT_OBJECT, not STT_NOTYPE.  */
+	  h->type = STT_OBJECT;
 	}
     }
 
-  gld${EMULATION_NAME}_before_allocation ();
+  gld${EMULATION_NAME}_after_allocation ();
 }
 
 EOF
 
 LDEMUL_BEFORE_ALLOCATION=elf_solaris2_before_allocation
+LDEMUL_AFTER_ALLOCATION=elf_solaris2_after_allocation


-- 
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Rainer Orth, Center for Biotechnology, Bielefeld University
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