[binutils-gdb] garbage collect debug sections when no alloc sections are kept

[Alan Modra <amodra at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=eb026f09eb6fcb96a5de1e655cdde041ba44affb

commit eb026f09eb6fcb96a5de1e655cdde041ba44affb
Author: Alan Modra <amodra@gmail.com>
Date:   Fri May 19 12:40:10 2017 +0930

    garbage collect debug sections when no alloc sections are kept
    
    The pr20882 testcase fails on a number of targets that add attribute
    or note sections to object files, and the default linker script says
    those sections should be kept.  This patch changes --gc-sections to
    drop debug and special sections like .comment when no SEC_ALLOC
    section in an object file is kept.  The assumption is that debug
    sections are describing code and data that will become part of the
    final image in memory.
    
    	* elflink.c (_bfd_elf_gc_mark_extra_sections): Don't keep
    	debug and special sections when no non-note alloc sections in an
    	object are kept.

Diff:
---
 bfd/ChangeLog | 6 ++++++
 bfd/elflink.c | 8 +++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index a85199a..a5ec80a 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2017-05-19  Alan Modra  <amodra@gmail.com>
+
+	* elflink.c (_bfd_elf_gc_mark_extra_sections): Don't keep
+	debug and special sections when no non-note alloc sections in an
+	object are kept.
+
 2017-05-18  Alan Modra  <amodra@gmail.com>
 
 	* arc-got.h: Don't compare boolean values against TRUE or FALSE.
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 387c6fd..71da4c9 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -12961,7 +12961,9 @@ _bfd_elf_gc_mark_extra_sections (struct bfd_link_info *info,
 	{
 	  if ((isec->flags & SEC_LINKER_CREATED) != 0)
 	    isec->gc_mark = 1;
-	  else if (isec->gc_mark)
+	  else if (isec->gc_mark
+		   && (isec->flags & SEC_ALLOC) != 0
+		   && elf_section_type (isec) != SHT_NOTE)
 	    some_kept = TRUE;
 
 	  if (!debug_frag_seen
@@ -12970,8 +12972,8 @@ _bfd_elf_gc_mark_extra_sections (struct bfd_link_info *info,
 	    debug_frag_seen = TRUE;
 	}
 
-      /* If no section in this file will be kept, then we can
-	 toss out the debug and special sections.  */
+      /* If no non-note alloc section in this file will be kept, then
+	 we can toss out the debug and special sections.  */
       if (!some_kept)
 	continue;