Tidy PR29893 and PR29908 fix

[Alan Modra <amodra@gmail.com>]

Hi Nick,
I'm removing the code you added to check "end < entry" for DWARF
version 4, because if you look at the way debug_addr_info is set up
you'll see that it is sorted and so
      entry = section->start + debug_addr_info [i]->addr_base;
	end = section->start + debug_addr_info [i + 1]->addr_base;
must result in end >= entry.  (I'd looked into adding a test there for
PR29893.)

Also, I wonder about all of these warning messages we've been adding
for fuzzed object file errors.  In normal operation of the tools they
will never be hit so we're just creating work for translators.  Maybe
they should mostly all just be
  "%pA+%#" PRIx64 " invalid\n", section, (uint64_t) offset

That's likely all someone debugging binutils or a producer of DWARF
needs.

	PR 29893
	PR 29908
	* dwarf.c (display_debug_addr): Combine dwarf5 unit_length checks.
	Delete dead code.

diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index 03b36afcec0..e08d51b4a97 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -7731,19 +7731,14 @@ display_debug_addr (struct dwarf_section *section,
 	  SAFE_BYTE_GET_AND_INC (length, curr_header, 4, entry);
 	  if (length == 0xffffffff)
 	    SAFE_BYTE_GET_AND_INC (length, curr_header, 8, entry);
-	  if (length > (size_t) (section->start + section->size - curr_header))
+	  if (length > (size_t) (section->start + section->size - curr_header)
+	      || length < (size_t) (entry - curr_header))
 	    {
 	      warn (_("Corrupt %s section: unit_length field of %#" PRIx64
-		      " too large\n"), section->name, length);
+		      " is invalid\n"), section->name, length);
 	      return 0;
 	    }
 	  end = curr_header + length;
-	  if (end < entry)
-	    {
-	      warn (_("Corrupt %s section header: length field (%lx) is too small\n"),
-		    section->name, (long) length);
-	      return 0;
-	    }
 	  SAFE_BYTE_GET_AND_INC (version, curr_header, 2, entry);
 	  if (version != 5)
 	    warn (_("Corrupt %s section: expecting version number 5 in header but found %d instead\n"),
@@ -7754,18 +7749,7 @@ display_debug_addr (struct dwarf_section *section,
 	  address_size += segment_selector_size;
 	}
       else
-	{
-	  end = section->start + debug_addr_info [i + 1]->addr_base;
-
-	  if (end < entry)
-	    {
-	      warn (_("Corrupt %s section: address base of entry %u (%lx) is less than entry %u (%lx)\n"),
-		    section->name,
-		    i, (long) debug_addr_info [i]->addr_base,
-		    i + 1, (long) debug_addr_info [i + 1]->addr_base);
-	      return 0;
-	    }
-	}
+	end = section->start + debug_addr_info [i + 1]->addr_base;
 
       header = end;
       idx = 0;

-- 
Alan Modra
Australia Development Lab, IBM