Re: PATCH: Add x32 support to sysdeps/x86_64/dl-tlsdesc.h

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Thu, Mar 22, 2012 at 9:58 AM, Roland McGrath <roland@hack.frob.com> wrote:
> I think the bit using the union warrants a comment explaining why it's there.
>
>> ? ? ? * sysdeps/x86_64/dl-tlsdesc.h (tlsdesc): Use anonymouse union
>
> typo: s/anonymouse/anonymous/
>
>> + ? ? ?ptrdiff_t (*entry)(struct tlsdesc *on_rax);
>
> Missing space before paren.
>
> With those nits fixed, I'm happy with the change.
> But I'd be happier yet if other people gave opinions
> about the union trick vs explicit #ifdef's padding fields.
>
>

Here is an updated patch.  Does anyone have any preference of
anonymous union vs. explicit #ifdef's padding fields?  My opinion
is we can go anonymous union for now.  We can always change
it to explicit #ifdef's padding fields if it is a real issue.  Any comments?

Thanks.

-- 
H.J.

2012-03-22  H.J. Lu  <hongjiu.lu@intel.com>

	* sysdeps/x86_64/dl-tlsdesc.h (tlsdesc): Use anonymous union
	to pad to uint64_t for each field.
	(dl_tls_index): Replace unsigned long with uint64_t.

diff --git a/sysdeps/x86_64/dl-tlsdesc.h b/sysdeps/x86_64/dl-tlsdesc.h
index 82a0109..f5635f7 100644
--- a/sysdeps/x86_64/dl-tlsdesc.h
+++ b/sysdeps/x86_64/dl-tlsdesc.h
@@ -29,14 +29,22 @@
 /* Type used to represent a TLS descriptor in the GOT.  */
 struct tlsdesc
 {
-  ptrdiff_t (*entry)(struct tlsdesc *on_rax);
-  void *arg;
+  union
+    {
+      ptrdiff_t (*entry) (struct tlsdesc *on_rax);
+      uint64_t entry_slot;
+    };
+  union
+    {
+      void *arg;
+      uint64_t arg_slot;
+    };
 };
 
 typedef struct dl_tls_index
 {
-  unsigned long int ti_module;
-  unsigned long int ti_offset;
+  uint64_t ti_module;
+  uint64_t ti_offset;
 } tls_index;
 
 /* Type used as the argument in a TLS descriptor for a symbol that