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Re: [Aarch64] Enable descriptors for nested functions in Ada
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Andreas Schwab <schwab at suse dot de>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 03 Apr 2017 11:23:30 +0200
- Subject: Re: [Aarch64] Enable descriptors for nested functions in Ada
- Authentication-results: sourceware.org; auth=none
- References: <6039323.u0bOnZZyyN@polaris> <mvmzifxkhl7.fsf@suse.de>
> In which way are the bits reserved?
I don't know, but that's what I was told by the ARM folks.
> This does not work for ILP32, because the descriptor address starts off
> at address 4 modulo 8, and adding 4 clears the bit.
I see, can you try the attached patchlet?
--
Eric Botcazou
Index: tree-nested.c
===================================================================
--- tree-nested.c (revision 246276)
+++ tree-nested.c (working copy)
@@ -496,6 +496,8 @@ static GTY(()) tree descriptor_type;
static tree
get_descriptor_type (struct nesting_info *info)
{
+ /* The base alignment is that of a function. */
+ const unsigned align = FUNCTION_ALIGNMENT (FUNCTION_BOUNDARY);
tree t;
if (descriptor_type)
@@ -505,6 +507,9 @@ get_descriptor_type (struct nesting_info
t = build_array_type (ptr_type_node, t);
t = build_decl (DECL_SOURCE_LOCATION (info->context),
FIELD_DECL, get_identifier ("__data"), t);
+ if (DECL_ALIGN (t) < align)
+ SET_DECL_ALIGN (t, align);
+ DECL_USER_ALIGN (t) = 1;
descriptor_type = make_node (RECORD_TYPE);
TYPE_NAME (descriptor_type) = get_identifier ("__builtin_descriptor");