i386: Avoid dynamic symbol with GOT reference in PIE

GOT reference to global symbol in PIE will lead to dynamic symbol.  It
becomes a problem when "time" or "times" is defined as a variable in
an executable, clashing with functions of the same name in libc.  If
a symbol isn't undefined weak symbol, don't make it dynamic in PIE and
generate R_386_RELATIVE relocation.

bfd/

	PR ld/21402
	* elf32-i386.c (elf_i386_link_hash_entry): Add
	no_finish_dynamic_symbol.
	(elf_i386_link_hash_newfunc): Set no_finish_dynamic_symbol to 0.
	(elf_i386_allocate_dynrelocs): If a symbol isn't undefined weak
	symbol, don't make it dynamic in PIE.
	(elf_i386_relocate_section): If a symbol isn't dynamic in PIE,
	set no_finish_dynamic_symbol and generate R_386_RELATIVE
	relocation for R_386_GOT32
	(elf_i386_finish_dynamic_symbol): Abort if no_finish_dynamic_symbol
	isn't 0.

ld/

	PR ld/21402
	* testsuite/ld-elf/indirect.exp: Don't skip PIE indirect5 and
	indirect6 tests on i386.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 4576020..ba2d134 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,19 @@
 2017-04-21  H.J. Lu  <hongjiu.lu@intel.com>
 
+       PR ld/21402
+       * elf32-i386.c (elf_i386_link_hash_entry): Add
+       no_finish_dynamic_symbol.
+       (elf_i386_link_hash_newfunc): Set no_finish_dynamic_symbol to 0.
+       (elf_i386_allocate_dynrelocs): If a symbol isn't undefined weak
+       symbol, don't make it dynamic in PIE.
+       (elf_i386_relocate_section): If a symbol isn't dynamic in PIE,
+       set no_finish_dynamic_symbol and generate R_386_RELATIVE
+       relocation for R_386_GOT32
+       (elf_i386_finish_dynamic_symbol): Abort if no_finish_dynamic_symbol
+       isn't 0.
+
+2017-04-21  H.J. Lu  <hongjiu.lu@intel.com>
+
        PR ld/19617
        PR ld/21086
        * elflink.c (elf_link_add_object_symbols): Require

diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 7af6863..9e71974 100644 (file)
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -820,6 +820,9 @@ struct elf_i386_link_hash_entry
   /* Symbol has non-GOT/non-PLT relocations in text sections.  */
   unsigned int has_non_got_reloc : 1;
 
+  /* Don't call finish_dynamic_symbol on this symbol.  */
+  unsigned int no_finish_dynamic_symbol : 1;
+
   /* 0: symbol isn't ___tls_get_addr.
      1: symbol is ___tls_get_addr.
      2: symbol is unknown.  */
@@ -959,6 +962,7 @@ elf_i386_link_hash_newfunc (struct bfd_hash_entry *entry,
       eh->gotoff_ref = 0;
       eh->has_got_reloc = 0;
       eh->has_non_got_reloc = 0;
+      eh->no_finish_dynamic_symbol = 0;
       eh->tls_get_addr = 2;
       eh->func_pointer_refcount = 0;
       eh->plt_got.offset = (bfd_vma) -1;
@@ -2863,10 +2867,14 @@ elf_i386_allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
       int tls_type = elf_i386_hash_entry(h)->tls_type;
 
       /* Make sure this symbol is output as a dynamic symbol.
-        Undefined weak syms won't yet be marked as dynamic.  */
+        Undefined weak syms won't yet be marked as dynamic.
+        PR ld/21402: If this symbol isn't undefined weak symbol,
+        don't make it dynamic in PIE.   */
       if (h->dynindx == -1
          && !h->forced_local
-         && !resolved_to_zero)
+         && !resolved_to_zero
+         && (h->root.type == bfd_link_hash_undefweak
+             || !bfd_link_pie (info)))
        {
          if (! bfd_elf_link_record_dynamic_symbol (info, h))
            return FALSE;
@@ -3818,6 +3826,7 @@ elf_i386_relocate_section (bfd *output_bfd,
       bfd_vma st_size;
       asection *resolved_plt;
       bfd_boolean resolved_to_zero;
+      bfd_boolean relative_reloc;
 
       r_type = ELF32_R_TYPE (rel->r_info);
       if (r_type == R_386_GNU_VTINHERIT
@@ -4268,6 +4277,7 @@ r_386_got32:
          if (htab->elf.sgot == NULL)
            abort ();
 
+         relative_reloc = FALSE;
          if (h != NULL)
            {
              bfd_boolean dyn;
@@ -4301,6 +4311,17 @@ r_386_got32:
                      bfd_put_32 (output_bfd, relocation,
                                  htab->elf.sgot->contents + off);
                      h->got.offset |= 1;
+
+                     if (h->dynindx == -1
+                         && !h->forced_local
+                         && h->root.type != bfd_link_hash_undefweak
+                         && bfd_link_pie (info))
+                       {
+                         /* PR ld/21402: If this symbol isn't dynamic
+                            in PIE, generate R_386_RELATIVE here.  */
+                         eh->no_finish_dynamic_symbol = 1;
+                         relative_reloc = TRUE;
+                       }
                    }
                }
              else
@@ -4322,27 +4343,29 @@ r_386_got32:
                {
                  bfd_put_32 (output_bfd, relocation,
                              htab->elf.sgot->contents + off);
+                 local_got_offsets[r_symndx] |= 1;
 
                  if (bfd_link_pic (info))
-                   {
-                     asection *s;
-                     Elf_Internal_Rela outrel;
-
-                     s = htab->elf.srelgot;
-                     if (s == NULL)
-                       abort ();
-
-                     outrel.r_offset = (htab->elf.sgot->output_section->vma
-                                        + htab->elf.sgot->output_offset
-                                        + off);
-                     outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
-                     elf_append_rel (output_bfd, s, &outrel);
-                   }
-
-                 local_got_offsets[r_symndx] |= 1;
+                   relative_reloc = TRUE;
                }
            }
 
+         if (relative_reloc)
+           {
+             asection *s;
+             Elf_Internal_Rela outrel;
+
+             s = htab->elf.srelgot;
+             if (s == NULL)
+               abort ();
+
+             outrel.r_offset = (htab->elf.sgot->output_section->vma
+                                + htab->elf.sgot->output_offset
+                                + off);
+             outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
+             elf_append_rel (output_bfd, s, &outrel);
+           }
+
          if (off >= (bfd_vma) -2)
            abort ();
 
@@ -5321,6 +5344,8 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
   plt_entry_size = GET_PLT_ENTRY_SIZE (output_bfd);
 
   eh = (struct elf_i386_link_hash_entry *) h;
+  if (eh->no_finish_dynamic_symbol)
+    abort ();
 
   /* We keep PLT/GOT entries without dynamic PLT/GOT relocations for
      resolved undefined weak symbols in executable so that their

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 86d9e51..c6daa9a 100644 (file)
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,5 +1,11 @@
 2017-04-21  H.J. Lu  <hongjiu.lu@intel.com>
 
+       PR ld/21402
+       * testsuite/ld-elf/indirect.exp: Don't skip PIE indirect5 and
+       indirect6 tests on i386.
+
+2017-04-21  H.J. Lu  <hongjiu.lu@intel.com>
+
        PR ld/19617
        PR ld/21086
        * testsuite/ld-elf/pr19617a.d: Pass --no-dynamic-linker to ld.

diff --git a/ld/testsuite/ld-elf/indirect.exp b/ld/testsuite/ld-elf/indirect.exp
index 2fa374b..fd7d189 100644 (file)
--- a/ld/testsuite/ld-elf/indirect.exp
+++ b/ld/testsuite/ld-elf/indirect.exp
@@ -222,11 +222,6 @@ foreach t [list indirect5a indirect5b indirect6a indirect6b] {
     }
 }
 
-# PR ld/21402: i386 doesn't support mixing different symbol types in PIE.
-if {[istarget "i?86-*-*"]} {
-    return
-}
-
 send_log "$CC -fPIE -pie $srcdir/$subdir/main.c -o tmpdir/pie"
 catch "exec $CC -fPIE -pie $srcdir/$subdir/main.c -o tmpdir/pie" exec_output
 send_log "$exec_output"