PTR_ADD and NPTR_ADD for bfd.h

This defines a couple of macros used to avoid ubsan complaints about
calculations involving NULL pointers.  PTR_ADD should be used in the
case where it is known that the offset is always zero with a NULL
pointer, and you'd like to know if a non-zero offset is ever used.
NPTR_ADD should be rarely used, but is defined for cases where a
non-zero offset is expected and should be ignored if the pointer is
NULL.

bfd/
	* bfd-in.h (PTR_ADD, NPTR_ADD): Define.
	* bfd-in2.h: Regenerate.
	* elf-eh-frame.c (adjust_eh_frame_local_symbols): Avoid NULL
	pointer calculations.
	* elflink.c (_bfd_elf_strip_zero_sized_dynamic_sections): Likewise.
	(bfd_elf_add_dt_needed_tag, elf_finalize_dynstr): Likewise.
	(elf_link_add_object_symbols, elf_link_input_bfd): Likewise.
	(bfd_elf_final_link, bfd_elf_gc_record_vtinherit): Likewise.
binutils/
	* objdump.c (disassemble_section): Use PTR_ADD for rel_ppend.

1 files changed, 16 insertions, 14 deletions

diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c
index 6ce6d22..b5ec814 100644
--- a/bfd/elf-eh-frame.c
+++ b/bfd/elf-eh-frame.c
@@ -1440,25 +1440,27 @@ static int
 adjust_eh_frame_local_symbols (const asection *sec,
 			       struct elf_reloc_cookie *cookie)
 {
-  unsigned int shndx;
-  Elf_Internal_Sym *sym;
-  Elf_Internal_Sym *end_sym;
   int adjusted = 0;
 
-  shndx = elf_section_data (sec)->this_idx;
-  end_sym = cookie->locsyms + cookie->locsymcount;
-  for (sym = cookie->locsyms + 1; sym < end_sym; ++sym)
-    if (sym->st_info <= ELF_ST_INFO (STB_LOCAL, STT_OBJECT)
-	&& sym->st_shndx == shndx)
-      {
-	bfd_signed_vma delta = offset_adjust (sym->st_value, sec);
+  if (cookie->locsymcount > 1)
+    {
+      unsigned int shndx = elf_section_data (sec)->this_idx;
+      Elf_Internal_Sym *end_sym = cookie->locsyms + cookie->locsymcount;
+      Elf_Internal_Sym *sym;
 
-	if (delta != 0)
+      for (sym = cookie->locsyms + 1; sym < end_sym; ++sym)
+	if (sym->st_info <= ELF_ST_INFO (STB_LOCAL, STT_OBJECT)
+	    && sym->st_shndx == shndx)
 	  {
-	    adjusted = 1;
-	    sym->st_value += delta;
+	    bfd_signed_vma delta = offset_adjust (sym->st_value, sec);
+
+	    if (delta != 0)
+	      {
+		adjusted = 1;
+		sym->st_value += delta;
+	      }
 	  }
-      }
+    }
   return adjusted;
 }