Patchwork [Ada] Do not generate special PARM_DECL in LTO mode

login
register
mail settings
Submitter Eric Botcazou
Date Oct. 22, 2012, 8:04 a.m.
Message ID <5495945.UYn8P9iJAj@polaris>
Download mbox | patch
Permalink /patch/193104/
State New
Headers show

Comments

Eric Botcazou - Oct. 22, 2012, 8:04 a.m.
We generate a special PARM_DECL for Out parameters passed by copy at -O0, but 
it doesn't play nice with LTO so this patch removes it when LTO is enabled.

Tested on x86_64-suse-linux, applied on the mainline and 4.7 branch.


2012-10-22  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Out_Parameter>: Do not
	generate the special PARM_DECL for an Out parameter in LTO mode.
Richard Guenther - Oct. 22, 2012, 8:39 a.m.
On Mon, Oct 22, 2012 at 10:04 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> We generate a special PARM_DECL for Out parameters passed by copy at -O0, but
> it doesn't play nice with LTO so this patch removes it when LTO is enabled.
>
> Tested on x86_64-suse-linux, applied on the mainline and 4.7 branch.

Shouldn't it be simply the abstract origin for the VAR_DECL?  Or be
not 'lowered'
here but be a 'proper' PARM_DECL with DECL_VALUE_EXPR?  That said,
how is debug info emitted in the optimize case?

No objection to the patch as-is, but guarding sth with flag_generate_lto always
makes me suspicious ;)

Richard.

> 2012-10-22  Eric Botcazou  <ebotcazou@adacore.com>
>
>         * gcc-interface/decl.c (gnat_to_gnu_entity) <E_Out_Parameter>: Do not
>         generate the special PARM_DECL for an Out parameter in LTO mode.
>
>
> --
> Eric Botcazou
Eric Botcazou - Oct. 22, 2012, 10 a.m.
> Shouldn't it be simply the abstract origin for the VAR_DECL?  Or be
> not 'lowered'
> here but be a 'proper' PARM_DECL with DECL_VALUE_EXPR?  That said,
> how is debug info emitted in the optimize case?

This is a PARM_DECL with DECL_VALUE_EXPR set to the VAR_DECL emitted in the 
outermost function scope.  It doesn't survive with optimization enabled so we 
don't bother generating it in this case.

Patch

Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c	(revision 192648)
+++ gcc-interface/decl.c	(working copy)
@@ -1503,7 +1503,11 @@  gnat_to_gnu_entity (Entity_Id gnat_entit
 	   the VAR_DECL.  Suppress debug info for the latter but make sure it
 	   will live on the stack so that it can be accessed from within the
 	   debugger through the PARM_DECL.  */
-	if (kind == E_Out_Parameter && definition && !optimize && debug_info_p)
+	if (kind == E_Out_Parameter
+	    && definition
+	    && debug_info_p
+	    && !optimize
+	    && !flag_generate_lto)
 	  {
 	    tree param = create_param_decl (gnu_entity_name, gnu_type, false);
 	    gnat_pushdecl (param, gnat_entity);