From: Alan Modra <amodra@gmail.com>
Date: Sun, 30 Aug 2020 23:02:32 +0000 (+0930)
Subject: PR26442 UBSAN: elf32-crx.c:512 cannot be represented in int
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c1f138f9557a14678f6f988975cba441f56e6137;p=binutils-gdb.git

PR26442 UBSAN: elf32-crx.c:512 cannot be represented in int

	PR 26442
	* elf32-crx.c (crx_elf_final_link_relocate): Calculate reloc_bits
	without undefined behaviour.  Tidy excess casts.
---

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 5d004cd7df0..7388c4d97ce 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2020-08-31  Alan Modra  <amodra@gmail.com>
+
+	PR 26442
+	* elf32-crx.c (crx_elf_final_link_relocate): Calculate reloc_bits
+	without undefined behaviour.  Tidy excess casts.
+
 2020-08-31  Alan Modra  <amodra@gmail.com>
 
 	* elf-m10300.c (mn10300_elf_relax_delete_bytes): Calculate
diff --git a/bfd/elf32-crx.c b/bfd/elf32-crx.c
index 82f1a3e4690..32db5b7fff2 100644
--- a/bfd/elf32-crx.c
+++ b/bfd/elf32-crx.c
@@ -506,25 +506,18 @@ crx_elf_final_link_relocate (reloc_howto_type *howto, bfd *input_bfd,
      as signed or unsigned.  */
   check = Rvalue >> howto->rightshift;
 
-  /* Assumes two's complement.  This expression avoids
-     overflow if howto->bitsize is the number of bits in
-     bfd_vma.  */
-  reloc_bits = (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
-
-  if (((bfd_vma) check & ~reloc_bits) != 0
-      && (((bfd_vma) check & ~reloc_bits)
-	  != (-(bfd_vma) 1 & ~reloc_bits)))
+  reloc_bits = ((bfd_vma) 1 << (howto->bitsize - 1) << 1) - 1;
+
+  if ((check & ~reloc_bits) != 0
+      && (check & ~reloc_bits) != ((bfd_vma) -1 & ~reloc_bits))
     {
       /* The above right shift is incorrect for a signed
 	 value.  See if turning on the upper bits fixes the
 	 overflow.  */
       if (howto->rightshift && (bfd_signed_vma) Rvalue < 0)
 	{
-	  check |= ((bfd_vma) - 1
-		    & ~((bfd_vma) - 1
-			>> howto->rightshift));
-	  if (((bfd_vma) check & ~reloc_bits)
-	      != (-(bfd_vma) 1 & ~reloc_bits))
+	  check |= (bfd_vma) -1 & ~((bfd_vma) -1 >> howto->rightshift);
+	  if ((check & ~reloc_bits) != ((bfd_vma) -1 & ~reloc_bits))
 	    return bfd_reloc_overflow;
 	}
       else
@@ -532,7 +525,7 @@ crx_elf_final_link_relocate (reloc_howto_type *howto, bfd *input_bfd,
     }
 
   /* Drop unwanted bits from the value we are relocating to.  */
-  Rvalue >>= (bfd_vma) howto->rightshift;
+  Rvalue >>= howto->rightshift;
 
   /* Apply dst_mask to select only relocatable part of the insn.  */
   Rvalue &= howto->dst_mask;