From: Alan Modra <amodra@gmail.com>
Date: Mon, 31 Mar 2025 08:49:28 +0000 (+1030)
Subject: ubsan: nds32 undefined shift
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7bc46c997839cbcb02f987f4cbf776b7a3bcc6f8;p=thirdparty%2Fbinutils-gdb.git

ubsan: nds32 undefined shift

Avoid implementation defined behaviour right shift of negative values,
and undefined behaviour left shift of negative values.  While this
change might give different results in the top bit of a bfd_vma
(rightshift is 1), that doesn't matter as only the bottom 8 bits of
the relocation are used.

	* elf32-nds32.c (nds32_elf_do_9_pcrel_reloc): Calculate relocation
	using a bfd_vma type.
---

diff --git a/bfd/elf32-nds32.c b/bfd/elf32-nds32.c
index e240c311841..1aff60a2505 100644
--- a/bfd/elf32-nds32.c
+++ b/bfd/elf32-nds32.c
@@ -2692,7 +2692,7 @@ nds32_elf_do_9_pcrel_reloc (bfd *               abfd,
 			    bfd_vma             symbol_value,
 			    bfd_vma             addend)
 {
-  bfd_signed_vma relocation;
+  bfd_vma relocation;
   unsigned short x;
   bfd_reloc_status_type status;
 
@@ -2708,7 +2708,7 @@ nds32_elf_do_9_pcrel_reloc (bfd *               abfd,
      before doing pcrel calculations.  */
   relocation -= (offset & -(bfd_vma) 2);
 
-  if (relocation < -ACCURATE_8BIT_S1 || relocation >= ACCURATE_8BIT_S1)
+  if (relocation + ACCURATE_8BIT_S1 >= 2 * ACCURATE_8BIT_S1)
     status = bfd_reloc_overflow;
   else
     status = bfd_reloc_ok;