[binutils-gdb] ELF: Discard non-alloc sections without section header

[H.J. Lu <hjl@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=02c1ba6c94d4bb3f53dfeeb4401c8434c7834a32

commit 02c1ba6c94d4bb3f53dfeeb4401c8434c7834a32
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed May 31 12:36:49 2023 -0700

    ELF: Discard non-alloc sections without section header
    
    Discard non-alloc sections when section headers are stripped.
    
    bfd/
    
            PR ld/25617
            * elf.c (_bfd_elf_assign_file_positions_for_non_load): Skip
            non-load sections without section header.
            (_bfd_elf_write_object_contents): Don't set the sh_name field
            without section header.  Write out the .shstrtab section only
            if its sh_offset field isn't -1.
    
    binutils/
    
            PR ld/25617
            * objcopy.c (is_strip_section_1): Remove non-alloc sections for
            --strip-section-headers.
    
    ld/
    
            PR ld/25617
            * ldlang.c (lang_discard_section_p): Discard non-alloc sections
            if we are stripping section headers.

Diff:
---
 bfd/elf.c          | 13 ++++++++++---
 binutils/objcopy.c |  7 ++++++-
 ld/ldlang.c        |  4 ++++
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/bfd/elf.c b/bfd/elf.c
index 8f6d7d1adba..4584b93a7ae 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -6601,6 +6601,10 @@ _bfd_elf_assign_file_positions_for_non_load (bfd *abfd)
   Elf_Internal_Ehdr *i_ehdrp;
   const struct elf_backend_data *bed;
 
+  /* Skip non-load sections without section header.  */
+  if ((abfd->flags & BFD_NO_SECTION_HEADER) != 0)
+    return true;
+
   off = elf_next_file_pos (abfd);
 
   shdrpp = elf_elfsections (abfd);
@@ -6724,9 +6728,11 @@ _bfd_elf_write_object_contents (bfd *abfd)
   num_sec = elf_numsections (abfd);
   for (count = 1; count < num_sec; count++)
     {
-      i_shdrp[count]->sh_name
-	= _bfd_elf_strtab_offset (elf_shstrtab (abfd),
-				  i_shdrp[count]->sh_name);
+      /* Don't set the sh_name field without section header.  */
+      if ((abfd->flags & BFD_NO_SECTION_HEADER) == 0)
+	i_shdrp[count]->sh_name
+	  = _bfd_elf_strtab_offset (elf_shstrtab (abfd),
+				    i_shdrp[count]->sh_name);
       if (bed->elf_backend_section_processing)
 	if (!(*bed->elf_backend_section_processing) (abfd, i_shdrp[count]))
 	  return false;
@@ -6743,6 +6749,7 @@ _bfd_elf_write_object_contents (bfd *abfd)
   /* Write out the section header names.  */
   t = elf_tdata (abfd);
   if (elf_shstrtab (abfd) != NULL
+      && t->shstrtab_hdr.sh_offset != -1
       && (bfd_seek (abfd, t->shstrtab_hdr.sh_offset, SEEK_SET) != 0
 	  || !_bfd_elf_strtab_emit (abfd, elf_shstrtab (abfd))))
     return false;
diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index 206d80bd0f1..3569b890c7d 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -1377,6 +1377,11 @@ is_strip_section_1 (bfd *abfd ATTRIBUTE_UNUSED, asection *sec)
 	return true;
     }
 
+  /* Remove non-alloc sections for --strip-section-headers.  */
+  if (strip_section_headers
+      && (bfd_section_flags (sec) & SEC_ALLOC) == 0)
+    return true;
+
   if ((bfd_section_flags (sec) & SEC_DEBUGGING) != 0)
     {
       if (strip_symbols == STRIP_DEBUG
@@ -2730,7 +2735,7 @@ copy_object (bfd *ibfd, bfd *obfd, const bfd_arch_info_type *input_arch)
 
       if (strip_section_headers)
 	{
-	  non_fatal (_("--strip_section_headers is unsupported on `%s'"),
+	  non_fatal (_("--strip-section-headers is unsupported on `%s'"),
 		     bfd_get_archive_filename (ibfd));
 	  return false;
 	}
diff --git a/ld/ldlang.c b/ld/ldlang.c
index f4a8b72869e..b3a89bf041b 100644
--- a/ld/ldlang.c
+++ b/ld/ldlang.c
@@ -2538,6 +2538,10 @@ lang_discard_section_p (asection *section)
       && (flags & SEC_DEBUGGING) != 0)
     discard = true;
 
+  /* Discard non-alloc sections if we are stripping section headers.  */
+  else if (config.no_section_header && (flags & SEC_ALLOC) == 0)
+    discard = true;
+
   return discard;
 }