x86: allow @size to also (sensibly) apply to sections

So far this (counter-intuitively) produced the size as recorded in the
(section) symbol. Obtain the section's size instead for section symbols.
(I wonder whether STT_SECTION symbols couldn't properly hold the
section's size in their st_size field, which in turn would likely mean
the internal symbol would also have its size properly updated.)

Note that this is not the same as the .sizeof.() pseudo-operator: @size
yields the local file's contribution to a section, while .sizeof.() gets
resolved by the linker to produce the final full section's size.

As to the 3rd each of the expected output lines in the changed testcase:
I can't find justification for zzz to come after yyy despite them being
defined in the opposite order in source. Therefore I think it's better
to permit both possible outcomes.

1 files changed, 5 insertions, 1 deletions

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index bd2da65..9c544ee 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -14241,7 +14241,11 @@ tc_gen_reloc (asection *section ATTRIBUTE_UNUSED, fixS *fixp)
 	{
 	  /* Resolve size relocation against local symbol to size of
 	     the symbol plus addend.  */
-	  valueT value = S_GET_SIZE (fixp->fx_addsy) + fixp->fx_offset;
+	  valueT value = S_GET_SIZE (fixp->fx_addsy);
+
+	  if (symbol_get_bfdsym (fixp->fx_addsy)->flags & BSF_SECTION_SYM)
+	    value = bfd_section_size (S_GET_SEGMENT (fixp->fx_addsy));
+	  value += fixp->fx_offset;
 	  if (fixp->fx_r_type == BFD_RELOC_SIZE32
 	      && object_64bit
 	      && !fits_in_unsigned_long (value))