[binutils-gdb] Account for .tbss alignment when adjusting start of relro

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b39910205f54538f53e77b9ae13f1d41ff728f5a

commit b39910205f54538f53e77b9ae13f1d41ff728f5a
Author: Alan Modra <amodra@gmail.com>
Date:   Thu Nov 19 15:00:13 2015 +1030

    Account for .tbss alignment when adjusting start of relro
    
    Another option might be to not bump "dot" for .tbss alignment in the
    main section sizing loop, but that could leak some of the following
    section into the TLS segment.  Leakage shouldn't matter since it will
    be to bytes past the end of .tdata, but for now this is a safer
    option.
    
    	PR ld/19264
    	* ldlang.c (lang_size_sections): Don't ignore .tbss when
    	adjusting start of relro region.

Diff:
---
 ld/ChangeLog |  6 ++++++
 ld/ldlang.c  | 15 ++++++++++-----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/ld/ChangeLog b/ld/ChangeLog
index d4324ec..d6bf9ab 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,9 @@
+2015-11-19  Alan Modra  <amodra@gmail.com>
+
+	PR ld/19264
+	* ldlang.c (lang_size_sections): Don't ignore .tbss when
+	adjusting start of relro region.
+
 2015-11-16  Nick Clifton  <nickc@redhat.com>
 
 	PR ld/19106
diff --git a/ld/ldlang.c b/ld/ldlang.c
index 3841afc..c45b912 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -5457,18 +5457,23 @@ lang_size_sections (bfd_boolean *relax, bfd_boolean check_regions)
 
       /* For sections in the relro segment..  */
       for (sec = link_info.output_bfd->section_last; sec; sec = sec->prev)
-	if (!IGNORE_SECTION (sec)
+	if ((sec->flags & SEC_ALLOC) != 0
 	    && sec->vma >= expld.dataseg.base
 	    && sec->vma < expld.dataseg.relro_end - expld.dataseg.relro_offset)
 	  {
 	    /* Where do we want to put this section so that it ends as
 	       desired?  */
-	    bfd_vma start = sec->vma;
-	    bfd_vma end = start + sec->size;
-	    bfd_vma bump = desired_end - end;
+	    bfd_vma start, end, bump;
+
+	    end = start = sec->vma;
+	    if ((sec->flags & SEC_HAS_CONTENTS) != 0
+		|| (sec->flags & SEC_THREAD_LOCAL) == 0)
+	      end += sec->size;
+	    bump = desired_end - end;
 	    /* We'd like to increase START by BUMP, but we must heed
 	       alignment so the increase might be less than optimum.  */
-	    start += bump & ~(((bfd_vma) 1 << sec->alignment_power) - 1);
+	    start += bump;
+	    start &= ~(((bfd_vma) 1 << sec->alignment_power) - 1);
 	    /* This is now the desired end for the previous section.  */
 	    desired_end = start;
 	  }