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Re: [trunk<-vta] Re: [vta, trunk?] declare frame decls for nested functions in the binding blocks
- From: Ian Lance Taylor <iant at google dot com>
- To: Alexandre Oliva <aoliva at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 01 Jun 2009 09:14:29 -0700
- Subject: Re: [trunk<-vta] Re: [vta, trunk?] declare frame decls for nested functions in the binding blocks
- References: <firstname.lastname@example.org> <email@example.com>
Alexandre Oliva <firstname.lastname@example.org> writes:
> On Jan 3, 2008, Alexandre Oliva <email@example.com> wrote:
>> Declarations with DECL_VALUE_EXPR in nested functions may refer to
>> frame declarations that end up optimized away, but debug information
>> for them should still reference the optimized-away frame decl
>> variable. We even have code to keep variables reference in
>> DECL_VALUE_EXPR around, but if we never add such variables to the
>> binding blocks, this doesn't quite work so well.
>> The problem only became apparent when debug stmts that claimed to set
>> these no-longer-existent variables caused Bad Things (TM) to happen.
>> This patch arranges for the frame decl variable to be added to the
>> binding block as well, such that it is kept around as needed.
> Ok for trunk?
> for gcc/ChangeLog
>>From Alexandre Oliva <firstname.lastname@example.org>
> * tree-nested.c (finalize_nesting_tree_1): Declare the
> frame_decl in the binding tree.
Is there any way to write a test case for this?
> Index: gcc/tree-nested.c
> --- gcc/tree-nested.c.orig 2009-05-28 05:33:39.000000000 -0300
> +++ gcc/tree-nested.c 2009-05-29 04:15:56.000000000 -0300
> @@ -1,5 +1,5 @@
> /* Nested function decomposition for GIMPLE.
> - Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
> + Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
> This file is part of GCC.
> @@ -2179,10 +2179,26 @@ finalize_nesting_tree_1 (struct nesting_
> /* In some cases the frame type will trigger the -Wpadded warning.
> This is not helpful; suppress it. */
> int save_warn_padded = warn_padded;
> + tree *adjust;
> warn_padded = 0;
> layout_type (root->frame_type);
> warn_padded = save_warn_padded;
> layout_decl (root->frame_decl, 0);
> + /* Remove root->frame_decl from root->new_local_var_chain, such
> + that we can declare it also in the lexical blocks, which
> + helps ensure virtual regs that end up appearing in its RTL
> + expression get substituted in instantiate_virtual_regs(). */
> + for (adjust = &root->new_local_var_chain;
> + *adjust != root->frame_decl;
> + adjust = &TREE_CHAIN (*adjust))
> + gcc_assert (TREE_CHAIN (*adjust));
> + *adjust = TREE_CHAIN (*adjust);
> + TREE_CHAIN (root->frame_decl) = NULL_TREE;
> + declare_vars (root->frame_decl,
> + gimple_seq_first_stmt (gimple_body (context)), true);
> /* If any parameters were referenced non-locally, then we need to