asan: assert (addr_ranges) <= (start)

asan: assert (addr_ranges) <= (start)

[Alan Modra]

That assert would be more obvious if it were reported as
"addr_ranges <= end_ranges".  Fix that by using the obvious variable
in the final loop.  Stop the assertion by using a signed comparison:
It's possible for the rounding up of the arange pointer to exceed the
end of the block when the block size is fuzzed.

	* dwarf.c (display_debug_aranges): Use "end_ranges" in loop
	displaying ranges rather that "start".  Simplify rounding up
	to 2*address_size boundary.  Use signed comparison in loop.

diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index d42dc64b397..a118c5b794e 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -7192,7 +7192,6 @@ display_debug_aranges (struct dwarf_section *section,
       dwarf_vma address;
       unsigned long sec_off;
       unsigned char address_size;
-      int excess;
       unsigned int offset_size;
       unsigned char *end_ranges;
 
@@ -7277,22 +7276,22 @@ display_debug_aranges (struct dwarf_section *section,
       addr_ranges = hdrptr;
 
       /* Must pad to an alignment boundary that is twice the address size.  */
-      excess = (hdrptr - start) % (2 * address_size);
-      if (excess)
-	addr_ranges += (2 * address_size) - excess;
+      addr_ranges += (2 * address_size - 1
+		      - (hdrptr - start - 1) % (2 * address_size));
 
-      start = end_ranges;
-
-      while (2u * address_size <= (size_t) (start - addr_ranges))
+      while (2 * address_size <= end_ranges - addr_ranges)
 	{
-	  SAFE_BYTE_GET_AND_INC (address, addr_ranges, address_size, start);
-	  SAFE_BYTE_GET_AND_INC (length, addr_ranges, address_size, start);
-
+	  SAFE_BYTE_GET_AND_INC (address, addr_ranges, address_size,
+				 end_ranges);
+	  SAFE_BYTE_GET_AND_INC (length, addr_ranges, address_size,
+				 end_ranges);
 	  printf ("    ");
 	  print_dwarf_vma (address, address_size);
 	  print_dwarf_vma (length, address_size);
 	  putchar ('\n');
 	}
+
+      start = end_ranges;
     }
 
   printf ("\n");

-- 
Alan Modra
Australia Development Lab, IBM