Properly handle indirect symbols

2012-07-03  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/3351
	* elflink.c (_bfd_elf_update_dynamic_flags): New.
	(_bfd_elf_merge_symbol): Update both real and indirect symbol
	dynamic flags.
	(_bfd_elf_add_default_symbol): Make the real symbol dynamic if
	the indirect symbol is defined in a shared library.
	(elf_link_add_object_symbols): Likewise.  If the indirect
	symbol has been forced local, don't make the real symbol
	dynamic.
	(elf_link_check_versioned_symbol): Check indirect symbol.
	(elf_link_output_extsym): Use real symbol definition when
	reporting indirect symbol error.  Check version info for
	dynamic versioned symbol.

2012-07-03  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/3351
	* ld-elf/indirect.exp: New file.
	* ld-elf/indirect1a.c: Likewise.
	* ld-elf/indirect1b.c: Likewise.
	* ld-elf/indirect1c.c: Likewise.
	* ld-elf/indirect2.c: Likewise.
	* ld-elf/indirect3.out: Likewise.
	* ld-elf/indirect3a.c: Likewise.
	* ld-elf/indirect3b.c: Likewise.
	* ld-elf/indirect3c.c: Likewise.
	* ld-elf/indirect4.out: Likewise.
	* ld-elf/indirect4a.c: Likewise.
	* ld-elf/indirect4b.c: Likewise.
	* ld-elf/indirect4c.c: Likewise.

bfd/ChangeLog

@@ -1,3 +1,19 @@
+2012-07-03  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/3351
+	* elflink.c (_bfd_elf_update_dynamic_flags): New.
+	(_bfd_elf_merge_symbol): Update both real and indirect symbol
+	dynamic flags.
+	(_bfd_elf_add_default_symbol): Make the real symbol dynamic if
+	the indirect symbol is defined in a shared library.
+	(elf_link_add_object_symbols): Likewise.  If the indirect
+	symbol has been forced local, don't make the real symbol
+	dynamic.
+	(elf_link_check_versioned_symbol): Check indirect symbol.
+	(elf_link_output_extsym): Use real symbol definition when
+	reporting indirect symbol error.  Check version info for
+	dynamic versioned symbol.
+
 2012-07-03  Alan Modra  <amodra@gmail.com>
 
 	PR ld/14207

bfd/elflink.c

@@ -892,6 +892,33 @@ elf_merge_st_other (bfd *abfd, struct elf_link_hash_entry *h,
     }
 }
 
+/* Mark if a symbol has a definition in a dynamic object or is
+   weak in all dynamic objects.  */
+
+static void
+_bfd_elf_mark_dynamic_def_weak (struct elf_link_hash_entry *h,
+				asection *sec, int bind)
+{
+  if (!h->dynamic_def)
+    {
+      if (!bfd_is_und_section (sec))
+	h->dynamic_def = 1;
+      else
+	{
+	  /* Check if this symbol is weak in all dynamic objects. If it
+	     is the first time we see it in a dynamic object, we mark
+	     if it is weak. Otherwise, we clear it.  */
+	  if (!h->ref_dynamic)
+	    {
+	      if (bind == STB_WEAK)
+		h->dynamic_weak = 1;
+	    }
+	  else if (bind != STB_WEAK)
+	    h->dynamic_weak = 0;
+	}
+    }
+}
+
 /* This function is called when we want to define a new symbol.  It
    handles the various cases which arise when we find a definition in
    a dynamic object, or when there is already a definition in a
@@ -920,6 +947,7 @@ _bfd_elf_merge_symbol (bfd *abfd,
 {
   asection *sec, *oldsec;
   struct elf_link_hash_entry *h;
+  struct elf_link_hash_entry *hi;
   struct elf_link_hash_entry *flip;
   int bind;
   bfd *oldbfd;
@@ -958,8 +986,9 @@ _bfd_elf_merge_symbol (bfd *abfd,
   if (!(*bed->relocs_compatible) (abfd->xvec, info->output_bfd->xvec))
     return TRUE;
 
-  /* For merging, we only care about real symbols.  */
-
+  /* For merging, we only care about real symbols.  But we need to make
+     sure that indirect symbol dynamic flags are updated.  */
+  hi = h;
   while (h->root.type == bfd_link_hash_indirect
 	 || h->root.type == bfd_link_hash_warning)
     h = (struct elf_link_hash_entry *) h->root.u.i.link;
@@ -1135,23 +1164,11 @@ _bfd_elf_merge_symbol (bfd *abfd,
   /* We need to remember if a symbol has a definition in a dynamic
      object or is weak in all dynamic objects. Internal and hidden
      visibility will make it unavailable to dynamic objects.  */
-  if (newdyn && !h->dynamic_def)
+  if (newdyn)
     {
-      if (!bfd_is_und_section (sec))
-	h->dynamic_def = 1;
-      else
-	{
-	  /* Check if this symbol is weak in all dynamic objects. If it
-	     is the first time we see it in a dynamic object, we mark
-	     if it is weak. Otherwise, we clear it.  */
-	  if (!h->ref_dynamic)
-	    {
-	      if (bind == STB_WEAK)
-		h->dynamic_weak = 1;
-	    }
-	  else if (bind != STB_WEAK)
-	    h->dynamic_weak = 0;
-	}
+      _bfd_elf_mark_dynamic_def_weak (h, sec, bind);
+      if (h != hi)
+	_bfd_elf_mark_dynamic_def_weak (hi, sec, bind);
     }
 
   /* If the old symbol has non-default visibility, we ignore the new
@@ -1163,6 +1180,7 @@ _bfd_elf_merge_symbol (bfd *abfd,
       *skip = TRUE;
       /* Make sure this symbol is dynamic.  */
       h->ref_dynamic = 1;
+      hi->ref_dynamic = 1;
       /* A protected symbol has external availability. Make sure it is
 	 recorded as dynamic.
 
@@ -1723,6 +1741,7 @@ _bfd_elf_add_default_symbol (bfd *abfd,
 	  if (! dynamic)
 	    {
 	      if (! info->executable
+		  || hi->def_dynamic
 		  || hi->ref_dynamic)
 		*dynsym = TRUE;
 	    }
@@ -3838,6 +3857,7 @@ error_free_dyn:
       flagword flags;
       const char *name;
       struct elf_link_hash_entry *h;
+      struct elf_link_hash_entry *hi;
       bfd_boolean definition;
       bfd_boolean size_change_ok;
       bfd_boolean type_change_ok;
@@ -4170,6 +4190,9 @@ error_free_dyn:
 	goto error_free_vers;
 
       h = *sym_hash;
+      /* We need to make sure that indirect symbol dynamic flags are
+	 updated.  */
+      hi = h;
       while (h->root.type == bfd_link_hash_indirect
 	     || h->root.type == bfd_link_hash_warning)
 	h = (struct elf_link_hash_entry *) h->root.u.i.link;
@@ -4358,25 +4381,38 @@ error_free_dyn:
 		      h->ref_dynamic = 1;
 		    }
 		}
-	      if (! info->executable
-		  || h->def_dynamic
-		  || h->ref_dynamic)
+
+	      /* If the indirect symbol has been forced local, don't
+		 make the real symbol dynamic.  */
+	      if ((h == hi || !hi->forced_local)
+		  && (! info->executable
+		      || h->def_dynamic
+		      || h->ref_dynamic))
 		dynsym = TRUE;
 	    }
 	  else
 	    {
 	      if (! definition)
-		h->ref_dynamic = 1;
+		{
+		  h->ref_dynamic = 1;
+		  hi->ref_dynamic = 1;
+		}
 	      else
 		{
 		  h->def_dynamic = 1;
 		  h->dynamic_def = 1;
+		  hi->def_dynamic = 1;
+		  hi->dynamic_def = 1;
 		}
-	      if (h->def_regular
-		  || h->ref_regular
-		  || (h->u.weakdef != NULL
-		      && ! new_weakdef
-		      && h->u.weakdef->dynindx != -1))
+
+	      /* If the indirect symbol has been forced local, don't
+		 make the real symbol dynamic.  */
+	      if ((h == hi || !hi->forced_local)
+		  && (h->def_regular
+		      || h->ref_regular
+		      || (h->u.weakdef != NULL
+			  && ! new_weakdef
+			  && h->u.weakdef->dynindx != -1)))
 		dynsym = TRUE;
 	    }
 
@@ -8441,6 +8477,10 @@ elf_link_check_versioned_symbol (struct bfd_link_info *info,
   if (!is_elf_hash_table (info->hash))
     return FALSE;
 
+  /* Check indirect symbol.  */
+  while (h->root.type == bfd_link_hash_indirect)
+    h = (struct elf_link_hash_entry *) h->root.u.i.link;
+
   switch (h->root.type)
     {
     default:
@@ -8670,6 +8710,11 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
     {
       bfd *def_bfd;
       const char *msg;
+      struct elf_link_hash_entry *hi = h;
+
+      /* Check indirect symbol.  */
+      while (hi->root.type == bfd_link_hash_indirect)
+	hi = (struct elf_link_hash_entry *) hi->root.u.i.link;
 
       if (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL)
 	msg = _("%B: internal symbol `%s' in %B is referenced by DSO");
@@ -8678,8 +8723,8 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
       else
 	msg = _("%B: local symbol `%s' in %B is referenced by DSO");
       def_bfd = flinfo->output_bfd;
-      if (h->root.u.def.section != bfd_abs_section_ptr)
-	def_bfd = h->root.u.def.section->owner;
+      if (hi->root.u.def.section != bfd_abs_section_ptr)
+	def_bfd = hi->root.u.def.section->owner;
       (*_bfd_error_handler) (msg, flinfo->output_bfd, def_bfd,
 			     h->root.root.string);
       bfd_set_error (bfd_error_bad_value);
@@ -8929,6 +8974,23 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
     {
       bfd_byte *esym;
 
+      /* Since there is no version information in the dynamic string,
+	 if there is no version info in symbol version section, we will
+	 have a run-time problem.  */
+      if (h->verinfo.verdef == NULL)
+	{
+	  char *p = strrchr (h->root.root.string, ELF_VER_CHR);
+
+	  if (p && p [1] != '\0')
+	    {
+	      (*_bfd_error_handler)
+		(_("%B: No symbol version section for versioned symbol `%s'"),
+		 flinfo->output_bfd, h->root.root.string);
+	      eoinfo->failed = TRUE;
+	      return FALSE;
+	    }
+	}
+
       sym.st_name = h->dynstr_index;
       esym = flinfo->dynsym_sec->contents + h->dynindx * bed->s->sizeof_sym;
       if (!check_dynsym (flinfo->output_bfd, &sym))

ld/testsuite/ChangeLog

@@ -1,3 +1,20 @@
+2012-07-03  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/3351
+	* ld-elf/indirect.exp: New file.
+	* ld-elf/indirect1a.c: Likewise.
+	* ld-elf/indirect1b.c: Likewise.
+	* ld-elf/indirect1c.c: Likewise.
+	* ld-elf/indirect2.c: Likewise.
+	* ld-elf/indirect3.out: Likewise.
+	* ld-elf/indirect3a.c: Likewise.
+	* ld-elf/indirect3b.c: Likewise.
+	* ld-elf/indirect3c.c: Likewise.
+	* ld-elf/indirect4.out: Likewise.
+	* ld-elf/indirect4a.c: Likewise.
+	* ld-elf/indirect4b.c: Likewise.
+	* ld-elf/indirect4c.c: Likewise.
+
 2012-07-02  Roland McGrath  <mcgrathr@google.com>
 
 	* ld/testsuite/ld-i386/tlsbin-nacl.rd: Update for symbol table changes.

ld/testsuite/ld-elf/indirect.exp

@@ -0,0 +1,126 @@
+# Expect script for various indirect symbol tests.
+#   Copyright 2012 Free Software Foundation, Inc.
+#
+# This file 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 of the License, or
+# (at your option) any later version.
+#
+# This program 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 this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+#
+
+#
+# Written by H.J. Lu (hongjiu.lu@intel.com)
+#
+
+# Exclude non-ELF targets.
+
+if ![is_elf_format] {
+    return
+}
+
+# Check if compiler works
+if { [which $CC] == 0 } {
+    return
+}
+
+proc check_link_message { cmd string testname } {
+    send_log "$cmd\n"
+    verbose "$cmd"
+    catch "exec $cmd" exec_output
+    send_log "$exec_output\n"
+    verbose "$exec_output"
+
+    foreach str $string {
+	if [string match "*$str*" $exec_output] {
+	    pass "$testname: $str"
+	} else {
+	    fail "$testname: $str"
+	}
+    }
+}
+
+if { ![ld_compile $CC $srcdir/$subdir/indirect1a.c tmpdir/indirect1a.o]
+     || ![ld_compile $CC $srcdir/$subdir/indirect1b.c tmpdir/indirect1b.o]
+     || ![ld_compile "$CC -fPIC" $srcdir/$subdir/indirect2.c tmpdir/indirect2.o]
+     || ![ld_compile $CC $srcdir/$subdir/indirect3a.c tmpdir/indirect3a.o]
+     || ![ld_compile $CC $srcdir/$subdir/indirect3b.c tmpdir/indirect3b.o]
+     || ![ld_compile $CC $srcdir/$subdir/indirect4a.c tmpdir/indirect4a.o]
+     || ![ld_compile $CC $srcdir/$subdir/indirect4b.c tmpdir/indirect4b.o] } {
+    unresolved "Indirect symbol tests"
+    return
+}
+
+set build_tests {
+  {"Build libindirect1c.so"
+   "-shared" "-fPIC"
+   {indirect1c.c} {} "libindirect1c.so"}
+  {"Build libindirect3c.so"
+   "-shared" "-fPIC"
+   {indirect3c.c} {} "libindirect3c.so"}
+  {"Build libindirect4c.so"
+   "-shared" "-fPIC"
+   {indirect4c.c} {} "libindirect4c.so"}
+}
+
+run_cc_link_tests $build_tests
+
+global ld
+
+set string ": final link failed: Bad value"
+set string1 ": local symbol \`foo\' in tmpdir/indirect1b.o is referenced by DSO"
+
+set testname "Indirect symbol 1a"
+set cmd "$ld -e start -o tmpdir/indirect1 tmpdir/indirect1a.o tmpdir/indirect1b.o tmpdir/libindirect1c.so"
+check_link_message "$cmd" [list $string1 $string] "$testname"
+
+set testname "Indirect symbol 1b"
+set cmd "$ld -e start -o tmpdir/indirect1 tmpdir/indirect1a.o tmpdir/libindirect1c.so tmpdir/indirect1b.o"
+check_link_message "$cmd" [list $string1 $string] "$testname"
+
+set string ": final link failed: Nonrepresentable section on output"
+set string2 ": No symbol version section for versioned symbol \`foo@FOO\'"
+set testname "Indirect symbol 2"
+set cmd "$ld -shared  -o tmpdir/indirect2.so tmpdir/indirect2.o"
+check_link_message "$cmd" [list $string2 $string] "$testname"
+
+# The following tests require running the executable generated by ld.
+if ![isnative] {
+    return
+}
+
+set run_tests {
+    {"Run with libindirect3c.so 1"
+     "tmpdir/indirect3a.o tmpdir/indirect3b.o tmpdir/libindirect3c.so" ""
+     {dummy.c} "indirect3a" "indirect3.out"}
+    {"Run with libindirect3c.so 2"
+     "tmpdir/indirect3a.o tmpdir/libindirect3c.so tmpdir/indirect3b.o" ""
+     {dummy.c} "indirect3b" "indirect3.out"}
+    {"Run with libindirect3c.so 3"
+     "tmpdir/indirect3b.o tmpdir/libindirect3c.so tmpdir/indirect3a.o" ""
+     {dummy.c} "indirect3c" "indirect3.out"}
+    {"Run with libindirect3c.so 4"
+     "tmpdir/libindirect3c.so tmpdir/indirect3b.o tmpdir/indirect3a.o" ""
+     {dummy.c} "indirect3d" "indirect3.out"}
+    {"Run with libindirect4c.so 1"
+     "tmpdir/indirect4a.o tmpdir/indirect4b.o tmpdir/libindirect4c.so" ""
+     {dummy.c} "indirect4a" "indirect4.out"}
+    {"Run with libindirect4c.so 2"
+     "tmpdir/indirect4a.o tmpdir/libindirect4c.so tmpdir/indirect4b.o" ""
+     {dummy.c} "indirect4b" "indirect4.out"}
+    {"Run with libindirect4c.so 3"
+     "tmpdir/indirect4b.o tmpdir/libindirect4c.so tmpdir/indirect4a.o" ""
+     {dummy.c} "indirect4c" "indirect4.out"}
+    {"Run with libindirect4c.so 4"
+     "tmpdir/libindirect4c.so tmpdir/indirect4b.o tmpdir/indirect4a.o" ""
+     {dummy.c} "indirect4d" "indirect4.out"}
+}
+
+run_ld_link_exec_tests [] $run_tests

ld/testsuite/ld-elf/indirect1a.c

@@ -0,0 +1,8 @@
+extern void bar (void);
+
+int
+start (void)
+{
+  bar ();
+  return 0;
+}

ld/testsuite/ld-elf/indirect1b.c

@@ -0,0 +1,6 @@
+void
+foo (void)
+{
+}
+
+asm (".symver foo,foo@FOO");

ld/testsuite/ld-elf/indirect1c.c

@@ -0,0 +1,7 @@
+extern void foo (void);
+
+void
+bar (void)
+{
+  foo ();
+}

ld/testsuite/ld-elf/indirect2.c

@@ -0,0 +1,9 @@
+extern void foo (void);
+
+asm (".symver foo,foo@@@FOO");
+
+void
+bar (void)
+{
+  foo ();
+}

ld/testsuite/ld-elf/indirect3.out

@@ -0,0 +1,2 @@
+MAIN
+DSO

ld/testsuite/ld-elf/indirect3a.c

@@ -0,0 +1,10 @@
+extern void bar (void);
+extern void foo (void);
+
+int
+main (void)
+{
+  foo ();
+  bar ();
+  return 0;
+}

ld/testsuite/ld-elf/indirect3b.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+void
+foo (void)
+{
+  printf ("MAIN\n");
+}
+
+asm (".symver foo,foo@FOO");

ld/testsuite/ld-elf/indirect3c.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+extern void foo (void);
+
+void
+foo (void)
+{
+  printf ("DSO\n");
+}
+
+void
+bar (void)
+{
+  foo ();
+}

ld/testsuite/ld-elf/indirect4.out

@@ -0,0 +1,2 @@
+MAIN2
+MAIN2

ld/testsuite/ld-elf/indirect4a.c

@@ -0,0 +1,10 @@
+extern void bar (void);
+extern void foo (void);
+
+int
+main (void)
+{
+  foo ();
+  bar ();
+  return 0;
+}

ld/testsuite/ld-elf/indirect4b.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+void
+foo2 (void)
+{
+  printf ("MAIN2\n");
+}
+
+asm (".symver foo2,foo@@FOO2");
+
+void
+foo1 (void)
+{
+  printf ("MAIN1\n");
+}
+
+asm (".symver foo1,foo@FOO1");

ld/testsuite/ld-elf/indirect4c.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+extern void foo (void);
+
+void
+foo (void)
+{
+  printf ("DSO\n");
+}
+
+void
+bar (void)
+{
+  foo ();
+}