FIXME for merging of e_flags and .gnu.attributes

Code in the linker, present before the addition of .gnu.attributes
support, results in shared libraries not being considered by BFD when
merging e_flags and .gnu.attributes from input files to the output.
That doesn't seem correct to me, but I don't know enough about all the
various ABIs to change the behaviour with any confidence.  So this
patch merely punts on dynamic objects in merge_private_bfd_data target
functions, with a FIXME for maintainer attention.

I haven't excluded shared libraries from being considered where the
target merge_private_bfd_data (a) already has code dealing with shared
libraries, or (b) where that function just sets the output to the most
constraining arch/mach combination and other fairly trivial merges, or
(c) when the target has no shared library linker support.

In (a) are: arc, arm, aarch64, riscv, sparc.
In (b) are: bpf, cris, csky, m32r, m68k, mn10300, nios2, tilegx,
	    tilepro, vax, visium, xtensa.
In (c) are: bpf, cr16, h8300, iq2000, m32c, m68hc11, m68hc12, mcore,
	    mep, msp430, mt, rl78, rx, v850.

	PR 25882
	* elf32-bfin.c (elf32_bfin_merge_private_bfd_data): Add FIXME.
	* elf32-frv.c (frv_elf_merge_private_bfd_data): Likewise.
	* elfxx-mips.c (_bfd_mips_elf_merge_private_bfd_data): Likewise.
	* elf32-nds32.c (nds32_elf_merge_private_bfd_data): Likewise.
	* elf32-score.c (s3_elf32_score_merge_private_bfd_data): Likewise.
	* elf32-score7.c (s7_elf32_score_merge_private_bfd_data): Likewise.
	* elf32-sh.c (sh_elf_merge_private_data): Likewise.
	* elf32-tic6x.c (elf32_tic6x_merge_attributes): Likewise.
	* elf64-ia64-vms.c (elf64_ia64_merge_private_bfd_data): Likewise.
	* elfnn-ia64.c (elfNN_ia64_merge_private_bfd_data): Likewise.

bfd/ChangeLog

@@ -1,3 +1,17 @@
+2020-05-01  Alan Modra  <amodra@gmail.com>
+
+	PR 25882
+	* elf32-bfin.c (elf32_bfin_merge_private_bfd_data): Add FIXME.
+	* elf32-frv.c (frv_elf_merge_private_bfd_data): Likewise.
+	* elfxx-mips.c (_bfd_mips_elf_merge_private_bfd_data): Likewise.
+	* elf32-nds32.c (nds32_elf_merge_private_bfd_data): Likewise.
+	* elf32-score.c (s3_elf32_score_merge_private_bfd_data): Likewise.
+	* elf32-score7.c (s7_elf32_score_merge_private_bfd_data): Likewise.
+	* elf32-sh.c (sh_elf_merge_private_data): Likewise.
+	* elf32-tic6x.c (elf32_tic6x_merge_attributes): Likewise.
+	* elf64-ia64-vms.c (elf64_ia64_merge_private_bfd_data): Likewise.
+	* elfnn-ia64.c (elfNN_ia64_merge_private_bfd_data): Likewise.
+
 2020-05-01  Alan Modra  <amodra@gmail.com>
 
 	PR 25882

bfd/elf32-bfin.c

@@ -4755,6 +4755,10 @@ elf32_bfin_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   flagword old_flags, new_flags;
   bfd_boolean error = FALSE;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   new_flags = elf_elfheader (ibfd)->e_flags;
   old_flags = elf_elfheader (obfd)->e_flags;
 

bfd/elf32-frv.c

@@ -6344,6 +6344,10 @@ frv_elf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   char new_opt[80];
   char old_opt[80];
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   new_opt[0] = old_opt[0] = '\0';
   new_flags = elf_elfheader (ibfd)->e_flags;
   old_flags = elf_elfheader (obfd)->e_flags;

bfd/elf32-nds32.c

@@ -6817,6 +6817,10 @@ nds32_elf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   flagword out_fpu_config;
   flagword in_fpu_config;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   /* TODO: Revise to use object-attributes instead.  */
   if (!nds32_check_vec_size (ibfd))
     return FALSE;

bfd/elf32-score.c

@@ -4021,6 +4021,10 @@ s3_elf32_score_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   if (!_bfd_generic_verify_endian_match (ibfd, info))
     return FALSE;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   in_flags  = elf_elfheader (ibfd)->e_flags;
   out_flags = elf_elfheader (obfd)->e_flags;
 

bfd/elf32-score7.c

@@ -3826,6 +3826,10 @@ s7_elf32_score_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   if (!_bfd_generic_verify_endian_match (ibfd, info))
     return FALSE;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   in_flags  = elf_elfheader (ibfd)->e_flags;
   out_flags = elf_elfheader (obfd)->e_flags;
 

bfd/elf32-sh.c

@@ -6028,6 +6028,10 @@ sh_elf_merge_private_data (bfd *ibfd, struct bfd_link_info *info)
 {
   bfd *obfd = info->output_bfd;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   if (! is_sh_elf (ibfd) || ! is_sh_elf (obfd))
     return TRUE;
 

bfd/elf32-tic6x.c

@@ -3724,6 +3724,10 @@ elf32_tic6x_merge_attributes (bfd *ibfd, struct bfd_link_info *info)
   int i;
   int array_align_in, array_align_out, array_expect_in, array_expect_out;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   if (!elf_known_obj_attributes_proc (obfd)[0].i)
     {
       /* This is the first object.  Copy the attributes.  */

bfd/elf64-ia64-vms.c

@@ -4233,6 +4233,10 @@ elf64_ia64_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   flagword in_flags;
   bfd_boolean ok = TRUE;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   /* Don't even pretend to support mixed-format linking.  */
   if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
       || bfd_get_flavour (obfd) != bfd_target_elf_flavour)

bfd/elfnn-ia64.c

@@ -4744,6 +4744,10 @@ elfNN_ia64_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   flagword in_flags;
   bfd_boolean ok = TRUE;
 
+  /* FIXME: What should be checked when linking shared libraries?  */
+  if ((ibfd->flags & DYNAMIC) != 0)
+    return TRUE;
+
   if (!is_ia64_elf (ibfd) || !is_ia64_elf (obfd))
     return TRUE;
 

bfd/elfxx-mips.c

@@ -15767,6 +15767,7 @@ _bfd_mips_elf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
   /* Check to see if the input BFD actually contains any sections.  If not,
      then it has no attributes, and its flags may not have been initialized
      either, but it cannot actually cause any incompatibility.  */
+  /* FIXME: This excludes any input shared library from consideration.  */
   for (sec = ibfd->sections; sec != NULL; sec = sec->next)
     {
       /* Ignore synthetic sections and empty .text, .data and .bss sections