Hi,
This patch makes local static variables to behave like global static variables
from IPA point of view (so they are present in the variable pool and emitted
via IPA channels instead being "on the side" of function bodies). I would like
opinion of more dwarf aware person whether my debug changes are fine here. It
seems to byte compare for produced assembly in the trivial testcases (function
having local static and function having local static being inlined several
times) and pass gdb testsuite but I don't claim I 100% know what I am doing
(the basic idea is to delay the debug info for final pass where we know what
variables will be output and what optimized out completely). The patch
is short but it took me surprisingly long to converge into this rather
obvious version (also due to some related bugs in varpool fixed now)
Bootstrapped/regtested i686-pc-gnu-linux, K?
Honza
2005-06-07 Jan Hubicka <jh (AT) suse (DOT) cz>
* cgraphunit.c (cgraph_create_edges): Do not walk BLCK; finalize
local statics when doing unit-at-a-time.
(): debug info.
* dwarf2out.c (decls_for_scope): Skip local statics.
(dwarf2out_decl): Handle local statics.
* passes.c (rest_of_decl_compilation): Do not differentiate
local and global statics in unit-at-a-time.
Index: cgraphunit.c
RCS file: /cvs/gcc/gcc/gcc/cgraphunit.c,v
retrieving revision 1.116
diff -c -3 -p -r1.116 cgraphunit.c
cgraphunit.c4 Jun 2005 20:23:13 -00001.116
cgraphunit.c7 Jun 2005 17:41:15 -0000
cgraph_create_edges (struct cgraph_node
543,568
walk_tree (bsi_stmt_ptr (bsi), record_reference, node, visited_nodes);
}
! /* Walk over any private statics that may take addresses of functions. */
! if (TREE_CDE (DECL_INITIAL (body)) == BLCK)
! {
! for (step = BLCK_VARS (DECL_INITIAL (body));
! step;
! step = TREE_CHAIN (step))
! if (DECL_INITIAL (step))
! walk_tree (&DECL_INITIAL (step), record_reference, node, visited_nodes);
}
-
- /* Also look here for private statics. */
- if (DECL_STRUCT_FUNCTIN (body))
- for (step = DECL_STRUCT_FUNCTIN (body)->unexpanded_var_list;
- step;
- step = TREE_CHAIN (step))
- {
- tree decl = TREE_VALUE (step);
- if (DECL_INITIAL (decl) && TREE_STATIC (decl))
- walk_tree (&DECL_INITIAL (decl), record_reference, node, visited_nodes);
- }
pointer_set_destroy (visited_nodes);
visited_nodes = NULL;
543,566
walk_tree (bsi_stmt_ptr (bsi), record_reference, node, visited_nodes);
}
! /* Look for initializers of constant variables and private statics. */
! for (step = DECL_STRUCT_FUNCTIN (body)->unexpanded_var_list;
! step;
! step = TREE_CHAIN (step))
! {
! tree decl = TREE_VALUE (step);
! if (TREE_CDE (decl) == VAR_DECL
! && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
! && flag_unit_at_a_time)
! /* FIXME: tree-inline.c duplicates static declarations during copying
! BIND_EXPR_VARS list (so they can be chained by TREE_CHAIN) while
! other occurences are still shared (as static variables
! are shared), so we need to look for the origin here. Kill it
! once this is cleaned up. */
! cgraph_varpool_finalize_decl (DECLRIGIN (decl));
! else if (TREE_CDE (decl) == VAR_DECL && DECL_INITIAL (decl))
! walk_tree (&DECL_INITIAL (decl), record_reference, node, visited_nodes);
}
pointer_set_destroy (visited_nodes);
visited_nodes = NULL;
(v
743,748
741,754
if (!TREE_ASM_WRITTEN (decl) && !node->alias && !DECL_EXTERNAL (decl))
{
assemble_variable (decl, 0, 1, 0);
+ /* Local static vairables are neever seen by check_global_declarations
+ so we need to output debug info by hand. */
+ if (decl_function_context (decl) && errorcount == 0 && sorrycount == 0)
+ {
+ timevar_push (TV_SYMUT);
+ (*debug_hooks->global_decl) (decl);
+ timevar_pop (TV_SYMUT);
+ }
changed = true;
}
node->next_needed = NULL;
Index: dwarf2out.c
RCS file: /cvs/gcc/gcc/gcc/dwarf2out.c,v
retrieving revision 1.598
diff -c -3 -p -r1.598 dwarf2out.c
dwarf2out.c7 Jun 2005 10:17:32 -00001.598
dwarf2out.c7 Jun 2005 17:41:16 -0000
decls_for_scope (tree stmt, dw_die_ref c
12524,12529
12524,12534
if (die != NULL && die->die_parent == NULL)
add_child_die (context_die, die);
+ /* Do not produce debug information for static variables since
+ these might be optimized out. We are called for these later
+ in */
+ if (TREE_CDE (decl) == VAR_DECL && TREE_STATIC (decl))
+ ;
else
gen_decl_die (decl, context_die);
}
dwarf2out_decl (tree decl)
13071,13076
13076,13085
if (DECL_EXTERNAL (decl) && !TREE_USED (decl))
return;
+ /* For local statics lookup proper context die. */
+ if (TREE_STATIC (decl) && decl_function_context (decl))
+ context_die = lookup_decl_die (DECL_CNTEXT (decl));
+
/* If we are in terse mode, don't generate any DIEs to represent any
variable declarations or definitions. */
if (debug_info_level <= DINFLEVEL_TERSE)
Index: passes.c
RCS file: /cvs/gcc/gcc/gcc/passes.c,v
retrieving revision 2.91
diff -c -3 -p -r2.91 passes.c
passes.c25 May 2005 12:33:32 -00002.91
passes.c7 Jun 2005 17:41:16 -0000
rest_of_decl_compilation (tree decl,
227,233
&& !DECL_EXTERNAL (decl))
{
if (flag_unit_at_a_time && !cgraph_global_info_ready
! && TREE_CDE (decl) != FUNCTIN_DECL && top_level)
cgraph_varpool_finalize_decl (decl);
else
assemble_variable (decl, top_level, at_end, 0);
227,233
&& !DECL_EXTERNAL (decl))
{
if (flag_unit_at_a_time && !cgraph_global_info_ready
! && TREE_CDE (decl) != FUNCTIN_DECL)
cgraph_varpool_finalize_decl (decl);
else
assemble_variable (decl, top_level, at_end, 0);

Tue, Jun 07, 2005 at 10:11:59PM +0200, Jan Hubicka wrote:
! /* FIXME: tree-inline.c duplicates static declarations during copying
! BIND_EXPR_VARS list (so they can be chained by TREE_CHAIN) while
! other occurences are still shared (as static variables
! are shared), so we need to look for the origin here. Kill it
! once this is cleaned up. */
! cgraph_varpool_finalize_decl (DECLRIGIN (decl));

I think I'd rather you fix this first, rather than put this hack in.

The rest of it seems ok.

r~

The dwarf2 changes seem fine.
Jason

Tue, Jun 07, 2005 at 10:11:59PM +0200, Jan Hubicka wrote:
! /* FIXME: tree-inline.c duplicates static declarations during copying
! BIND_EXPR_VARS list (so they can be chained by TREE_CHAIN) while
! other occurences are still shared (as static variables
! are shared), so we need to look for the origin here. Kill it
! once this is cleaned up. */
! cgraph_varpool_finalize_decl (DECLRIGIN (decl));

I think I'd rather you fix this first, rather than put this hack in.

I don't see how to do that easilly - the BIND_EXPRs are linked via
TREE_CHAIN pointers and we need the local static in two BIND_EXPRs at
once, but we have only one link pointer.
sollution I saw was to make C++ frontend lower function before
clonning (so we don't clone at generic level at all). I got half way
throught my way across C++ frontend, I might try to finish it if this
plan sounds sane, but I would preffer doing so incrementally.

Honza

The rest of it seems ok.

r~

Tue, Jun 07, 2005 at 10:11:59PM +0200, Jan Hubicka wrote:
! /* FIXME: tree-inline.c duplicates static declarations during copying
! BIND_EXPR_VARS list (so they can be chained by TREE_CHAIN) while
! other occurences are still shared (as static variables
! are shared), so we need to look for the origin here. Kill it
! once this is cleaned up. */
! cgraph_varpool_finalize_decl (DECLRIGIN (decl));

I think I'd rather you fix this first, rather than put this hack in.

I don't see how to do that easilly - the BIND_EXPRs are linked via
TREE_CHAIN pointers and we need the local static in two BIND_EXPRs at
once, but we have only one link pointer.
sollution I saw was to make C++ frontend lower function before
clonning (so we don't clone at generic level at all). I got half way
throught my way across C++ frontend, I might try to finish it if this
plan sounds sane, but I would preffer doing so incrementally.
K and the point where I stopped is that C++ frontend currently produce
some code in DECL_SAVED_TREE while constructing the clone (apparently
initializing the parameters that differ from original) and then it
appends the duplicated body.
Now we have the initializers in generic and the body in gimple that
means that either C++ frontend would have to produce gimple directly
when constructing the initializers or gimplify the partical function
body before pasting in the inlined body. Since I would like to keep
frontend's generic and backend's gimple separated so generic or gimple
memory representation might change at some time, this looks like nasty
obstackle.
What sounds like resonable way to solve this? (assuming that this is
resonable plan at first place ;), but killing the generic code from
tree-inline is pretty desirable cleanup)

Honza

The rest of it seems ok.

r~

Wed, Jun 08, 2005 at 11:02:51AM +0200, Jan Hubicka wrote:
I don't see how to do that easilly - the BIND_EXPRs are linked via
TREE_CHAIN pointers and we need the local static in two BIND_EXPRs at
once, but we have only one link pointer.

I don't think it needs to be linked into the bind_expr at all.

We don't use the BIND_EXPRs for debugging, only the BLCKs. You may
need to insert the variable into the inliner's unexpanded_var_list,
to make sure that its DECL_RTL gets created at the right time, but
that should be about it.

r~

Wed, Jun 08, 2005 at 11:02:51AM +0200, Jan Hubicka wrote:
I don't see how to do that easilly - the BIND_EXPRs are linked via
TREE_CHAIN pointers and we need the local static in two BIND_EXPRs at
once, but we have only one link pointer.

I don't think it needs to be linked into the bind_expr at all.

I tried simply skipping them, problem I run into was the fact that
gimplifier then didn't put it into unexpanded_var_list and thus it never
got finalized when the master copy of function got optimized out

We don't use the BIND_EXPRs for debugging, only the BLCKs. You may
need to insert the variable into the inliner's unexpanded_var_list,

K, so you suggest instead of remapping it, simply go ahead and drop it
into the unexpanded_var_list (so we will have generic functions with
this list partly initialized before we gimplify)?

Honza
to make sure that its DECL_RTL gets created at the right time, but
that should be about it.

r~

Wed, Jun 08, 2005 at 09:39:17PM +0200, Jan Hubicka wrote:
K, so you suggest instead of remapping it, simply go ahead and drop it
into the unexpanded_var_list (so we will have generic functions with
this list partly initialized before we gimplify)?
Yes.
r~

Wed, Jun 08, 2005 at 09:39:17PM +0200, Jan Hubicka wrote:
K, so you suggest instead of remapping it, simply go ahead and drop it
into the unexpanded_var_list (so we will have generic functions with
this list partly initialized before we gimplify)?

Yes.
K, done thus

Bootstrapped/regtested i686-pc-gnu-linux, K?

Honza

2005-06-07 Jan Hubicka <jh (AT) suse (DOT) cz>
* cgraphunit.c (cgraph_create_edges): Do not walk BLCK; finalize
local statics when doing unit-at-a-time.
(): debug info.
* dwarf2out.c (decls_for_scope): Skip local statics.
(dwarf2out_decl): Handle local statics.
* passes.c (rest_of_decl_compilation): Do not differentiate
local and global statics in unit-at-a-time.
* tree-inline.c (remap_decls): Put local static into
unexpanded_vars_list rather than introducing duplicated VAR_DECL
node.
Index: cgraphunit.c

RCS file: /cvs/gcc/gcc/gcc/cgraphunit.c,v
retrieving revision 1.116
diff -c -3 -p -r1.116 cgraphunit.c
cgraphunit.c4 Jun 2005 20:23:13 -00001.116
cgraphunit.c9 Jun 2005 09:57:18 -0000
cgraph_create_edges (struct cgraph_node
543,568
walk_tree (bsi_stmt_ptr (bsi), record_reference, node, visited_nodes);
}

! /* Walk over any private statics that may take addresses of functions. */
! if (TREE_CDE (DECL_INITIAL (body)) == BLCK)
! {
! for (step = BLCK_VARS (DECL_INITIAL (body));
! step;
! step = TREE_CHAIN (step))
! if (DECL_INITIAL (step))
! walk_tree (&DECL_INITIAL (step), record_reference, node, visited_nodes);
}
-
- /* Also look here for private statics. */
- if (DECL_STRUCT_FUNCTIN (body))
- for (step = DECL_STRUCT_FUNCTIN (body)->unexpanded_var_list;
- step;
- step = TREE_CHAIN (step))
- {
- tree decl = TREE_VALUE (step);
- if (DECL_INITIAL (decl) && TREE_STATIC (decl))
- walk_tree (&DECL_INITIAL (decl), record_reference, node, visited_nodes);
- }

pointer_set_destroy (visited_nodes);
visited_nodes = NULL;
543,561
walk_tree (bsi_stmt_ptr (bsi), record_reference, node, visited_nodes);
}

! /* Look for initializers of constant variables and private statics. */
! for (step = DECL_STRUCT_FUNCTIN (body)->unexpanded_var_list;
! step;
! step = TREE_CHAIN (step))
! {
! tree decl = TREE_VALUE (step);
! if (TREE_CDE (decl) == VAR_DECL
! && (TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
! && flag_unit_at_a_time)
! cgraph_varpool_finalize_decl (decl);
! else if (TREE_CDE (decl) == VAR_DECL && DECL_INITIAL (decl))
! walk_tree (&DECL_INITIAL (decl), record_reference, node, visited_nodes);
}

pointer_set_destroy (visited_nodes);
visited_nodes = NULL;
(v
743,748
736,749
if (!TREE_ASM_WRITTEN (decl) && !node->alias && !DECL_EXTERNAL (decl))
{
assemble_variable (decl, 0, 1, 0);
+ /* Local static vairables are neever seen by check_global_declarations
+ so we need to output debug info by hand. */
+ if (decl_function_context (decl) && errorcount == 0 && sorrycount == 0)
+ {
+ timevar_push (TV_SYMUT);
+ (*debug_hooks->global_decl) (decl);
+ timevar_pop (TV_SYMUT);
+ }
changed = true;
}
node->next_needed = NULL;
Index: dwarf2out.c

RCS file: /cvs/gcc/gcc/gcc/dwarf2out.c,v
retrieving revision 1.600
diff -c -3 -p -r1.600 dwarf2out.c
dwarf2out.c8 Jun 2005 07:48:16 -00001.600
dwarf2out.c9 Jun 2005 09:57:19 -0000
decls_for_scope (tree stmt, dw_die_ref c
12523,12528
12523,12533

if (die != NULL && die->die_parent == NULL)
add_child_die (context_die, die);
+ /* Do not produce debug information for static variables since
+ these might be optimized out. We are called for these later
+ in */
+ if (TREE_CDE (decl) == VAR_DECL && TREE_STATIC (decl))
+ ;
else
gen_decl_die (decl, context_die);
}
dwarf2out_decl (tree decl)
13070,13075
13075,13084
if (DECL_EXTERNAL (decl) && !TREE_USED (decl))
return;

+ /* For local statics lookup proper context die. */
+ if (TREE_STATIC (decl) && decl_function_context (decl))
+ context_die = lookup_decl_die (DECL_CNTEXT (decl));
+
/* If we are in terse mode, don't generate any DIEs to represent any
variable declarations or definitions. */
if (debug_info_level <= DINFLEVEL_TERSE)
Index: passes.c

RCS file: /cvs/gcc/gcc/gcc/passes.c,v
retrieving revision 2.91
diff -c -3 -p -r2.91 passes.c
passes.c25 May 2005 12:33:32 -00002.91
passes.c9 Jun 2005 09:57:19 -0000
rest_of_decl_compilation (tree decl,
227,233
&& !DECL_EXTERNAL (decl))
{
if (flag_unit_at_a_time && !cgraph_global_info_ready
! && TREE_CDE (decl) != FUNCTIN_DECL && top_level)
cgraph_varpool_finalize_decl (decl);
else
assemble_variable (decl, top_level, at_end, 0);
227,233
&& !DECL_EXTERNAL (decl))
{
if (flag_unit_at_a_time && !cgraph_global_info_ready
! && TREE_CDE (decl) != FUNCTIN_DECL)
cgraph_varpool_finalize_decl (decl);
else
assemble_variable (decl, top_level, at_end, 0);
Index: tree-inline.c

RCS file: /cvs/gcc/gcc/gcc/tree-inline.c,v
retrieving revision 1.192
diff -c -3 -p -r1.192 tree-inline.c
tree-inline.c6 Jun 2005 19:31:26 -00001.192
tree-inline.c9 Jun 2005 09:57:19 -0000
remap_decls (tree decls, inline_data *id
385,390
385,401
{
tree new_var;

+ /* We can not chain the local static declarations into the list
+ as we can't duplicate them or break one decl rule. Go ahead and link
+ them into unexpanded_var_list. */
+ if (! (old_var, id->callee)
+ && !DECL_EXTERNAL (old_var))
+ {
+ cfun->unexpanded_var_list = tree_cons (NULL_TREE, old_var,
+ cfun->unexpanded_var_list);
+ continue;
+ }
+
/* Remap the variable. */
new_var = remap_decl (old_var, id);

Thu, Jun 09, 2005 at 04:12:01PM +0200, Jan Hubicka wrote:
* cgraphunit.c (cgraph_create_edges): Do not walk BLCK; finalize
local statics when doing unit-at-a-time.
(): debug info.
* dwarf2out.c (decls_for_scope): Skip local statics.
(dwarf2out_decl): Handle local statics.
* passes.c (rest_of_decl_compilation): Do not differentiate
local and global statics in unit-at-a-time.
* tree-inline.c (remap_decls): Put local static into
unexpanded_vars_list rather than introducing duplicated VAR_DECL
node.

r~