-Wstringop-truncation warnings

This patch is aimed at silencing gcc8 -Wstringop-truncation warnings.

Unfortunately adding  __attribute__ ((__nonstring)) doesn't work in a
number of the places patched here, (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85643) so if you have
recent glibc headers installed you'll need to configure binutils with
--disable-werror to compile using gcc8 or gcc9.

include/
	* ansidecl.h: Import from gcc.
	* coff/internal.h (struct internal_scnhdr): Add ATTRIBUTE_NONSTRING
	to s_name.
	(struct internal_syment): Add ATTRIBUTE_NONSTRING to _n_name.
bfd/
	* elf-linux-core.h (struct elf_external_linux_prpsinfo32_ugid32),
	(struct elf_external_linux_prpsinfo32_ugid16),
	(struct elf_external_linux_prpsinfo64_ugid32),
	(struct elf_external_linux_prpsinfo64_ugid16): Add ATTRIBUTE_NONSTRING
	to pr_fname and pr_psargs fields.  Remove GCC diagnostic pragmas.
	Move comment to..
	* elf.c (elfcore_write_prpsinfo): ..here.  Indent nested preprocessor
	directives.
	* elf32-arm.c (elf32_arm_nabi_write_core_note): Add ATTRIBUTE_NONSTRING
	to data.
	* elf32-ppc.c (ppc_elf_write_core_note): Likewise.
	* elf32-s390.c (elf_s390_write_core_note): Likewise.
	* elf64-s390.c (elf_s390_write_core_note): Likewise.
	* elfxx-aarch64.c (_bfd_aarch64_elf_write_core_note): Likewise.
	* elf64-x86-64.c (elf_x86_64_write_core_note): Add GCC diagnostic
	pragmas.
	* peXXigen.c (_bfd_XXi_swap_scnhdr_out): Use strnlen to avoid
	false positive gcc-8 warning.
gas/
	* config/obj-evax.c (shorten_identifier): Use memcpy in place
	of strncpy.
	* config/obj-macho.c (obj_mach_o_make_or_get_sect): Ensure
	segname and sectname fields are NUL terminated.

1 files changed, 24 insertions, 11 deletions

diff --git a/bfd/elf.c b/bfd/elf.c
index bd9ffcc..21bc4e7 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -10508,9 +10508,22 @@ elfcore_write_note (bfd *abfd,
   return buf;
 }
 
+/* gcc-8 warns (*) on all the strncpy calls in this function about
+   possible string truncation.  The "truncation" is not a bug.  We
+   have an external representation of structs with fields that are not
+   necessarily NULL terminated and corresponding internal
+   representation fields that are one larger so that they can always
+   be NULL terminated.
+   gcc versions between 4.2 and 4.6 do not allow pragma control of
+   diagnostics inside functions, giving a hard error if you try to use
+   the finer control available with later versions.
+   gcc prior to 4.2 warns about diagnostic push and pop.
+   gcc-5, gcc-6 and gcc-7 warn that -Wstringop-truncation is unknown,
+   unless you also add #pragma GCC diagnostic ignored "-Wpragma".
+   (*) Depending on your system header files!  */
 #if GCC_VERSION >= 8000
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wstringop-truncation"
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wstringop-truncation"
 #endif
 char *
 elfcore_write_prpsinfo (bfd  *abfd,
@@ -10531,16 +10544,16 @@ elfcore_write_prpsinfo (bfd  *abfd,
     }
 
 #if defined (HAVE_PRPSINFO_T) || defined (HAVE_PSINFO_T)
-#if defined (HAVE_PRPSINFO32_T) || defined (HAVE_PSINFO32_T)
+# if defined (HAVE_PRPSINFO32_T) || defined (HAVE_PSINFO32_T)
   if (bed->s->elfclass == ELFCLASS32)
     {
-#if defined (HAVE_PSINFO32_T)
+#  if defined (HAVE_PSINFO32_T)
       psinfo32_t data;
       int note_type = NT_PSINFO;
-#else
+#  else
       prpsinfo32_t data;
       int note_type = NT_PRPSINFO;
-#endif
+#  endif
 
       memset (&data, 0, sizeof (data));
       strncpy (data.pr_fname, fname, sizeof (data.pr_fname));
@@ -10549,15 +10562,15 @@ elfcore_write_prpsinfo (bfd  *abfd,
 				 "CORE", note_type, &data, sizeof (data));
     }
   else
-#endif
+# endif
     {
-#if defined (HAVE_PSINFO_T)
+# if defined (HAVE_PSINFO_T)
       psinfo_t data;
       int note_type = NT_PSINFO;
-#else
+# else
       prpsinfo_t data;
       int note_type = NT_PRPSINFO;
-#endif
+# endif
 
       memset (&data, 0, sizeof (data));
       strncpy (data.pr_fname, fname, sizeof (data.pr_fname));
@@ -10571,7 +10584,7 @@ elfcore_write_prpsinfo (bfd  *abfd,
   return NULL;
 }
 #if GCC_VERSION >= 8000
-#pragma GCC diagnostic pop
+# pragma GCC diagnostic pop
 #endif
 
 char *