PR23595, simple objcopy of executable failure for msp430-elf

[Alan Modra <amodra at gmail dot com>]

VMA of the first section in the segment containing the ELF file header
(and possibly section headers too) can't be used to reliably find the
size of the headers plus padding.  What's really needed is sh_offset
of the first section assuming it has contents (vma does have a
relationship to sh_offset, but is only guaranteed in demand paged
executables).

If the first section is SHT_NOBITS and it hasn't been converted to
have file contents by the existence of a following SHT_PROGBITS
section in the same segment, the sh_offset value also isn't reliable.

	PR 23595
	elf.c (copy_elf_program_header): When first segment contains
	only the headers and SHT_NOBITS sections, use segment p_filesz
	to calculate header and padding size.  Use filepos of the first
	section otherwise.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 792df8a1fa..9a3b9b1ec2 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2018-09-03  Jozef Lawrynowicz <jozef.l@mittosystems.com>
+	    Alan Modra  <amodra@gmail.com>
+
+	PR 23595
+	elf.c (copy_elf_program_header): When first segment contains
+	only the headers and SHT_NOBITS sections, use segment p_filesz
+	to calculate header and padding size.  Use filepos of the first
+	section otherwise.
+
 018-08-31  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/23600
diff --git a/bfd/elf.c b/bfd/elf.c
index b8860c453b..02d605c19c 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -7235,6 +7235,7 @@ copy_elf_program_header (bfd *ibfd, bfd *obfd)
       Elf_Internal_Shdr *this_hdr;
       asection *first_section = NULL;
       asection *lowest_section;
+      bfd_boolean no_contents = TRUE;
 
       /* Compute how many sections are in this segment.  */
       for (section = ibfd->sections, section_count = 0;
@@ -7246,6 +7247,8 @@ copy_elf_program_header (bfd *ibfd, bfd *obfd)
 	    {
 	      if (first_section == NULL)
 		first_section = section;
+	      if (elf_section_type (section) != SHT_NOBITS)
+		no_contents = FALSE;
 	      section_count++;
 	    }
 	}
@@ -7342,8 +7345,17 @@ copy_elf_program_header (bfd *ibfd, bfd *obfd)
 	}
 
       if (map->includes_filehdr && lowest_section != NULL)
-	/* We need to keep the space used by the headers fixed.  */
-	map->header_size = lowest_section->vma - segment->p_vaddr;
+	{
+	  /* Try to keep the space used by the headers plus any
+	     padding fixed.  If there are sections with file contents
+	     in this segment then the lowest sh_offset is the best
+	     guess.  Otherwise the segment only has file contents for
+	     the headers, and p_filesz is the best guess.  */
+	  if (no_contents)
+	    map->header_size = segment->p_filesz;
+	  else
+	    map->header_size = lowest_section->filepos;
+	}
 
       if (!map->includes_phdrs
 	  && !map->includes_filehdr

-- 
Alan Modra
Australia Development Lab, IBM