This is a regression present on the mainline. The compiler crashes during the
function unnesting pass because of an out-of-context temporary, but the root
cause of the problem is incorrect sharing of a tree node. The problem has
probably been latent since gimplification was devised: while the DECL_SIZE and
DECL_SIZE_UNIT trees of VAR_DECLs are visited by walk_tree (via BIND_EXPR),
this isn't the case for RESULT_DECL. As a result, if it has variable size
(this now happens much more often in Ada), its subtrees aren't unshared and
this is problematic.
The proposed fix is to unshared them manually in unshare_body. To implement
this, the awkward interface to gimplify_body/unshare_body, where you pass both
a pointer to the body and the decl itself and later need to test whether they
are related, is simplified as the 2 calls of gimplify_body are idiomatic.
Tested on i586-suse-linux, OK for the mainline?
2012-01-10 Eric Botcazou <ebotca...@adacore.com>
* gimple.h (gimplify_body): Remove first argument.
* gimplify.c (copy_if_shared): Add DATA argument. Do not create the
pointer set here, instead just pass DATA to walk_tree.
(unshare_body): Remove BODY_P argument and adjust. Create the pointer
set here and invoke copy_if_shared on the size trees of DECL_RESULT.
(unvisit_body): Likewise, but with unmark_visited.
(gimplify_body): Remove BODY_P argument and adjust.
(gimplify_function_tree): Adjust call to gimplify_body.
* omp-low.c (finalize_task_copyfn): Likewise.
2012-01-10 Eric Botcazou <ebotca...@adacore.com>
* gnat.dg/array19.ad[sb]: New test.
--
Eric Botcazou
Index: gimple.h
===================================================================
--- gimple.h (revision 182780)
+++ gimple.h (working copy)
@@ -1099,7 +1099,7 @@ extern enum gimplify_status gimplify_exp
extern void gimplify_type_sizes (tree, gimple_seq *);
extern void gimplify_one_sizepos (tree *, gimple_seq *);
extern bool gimplify_stmt (tree *, gimple_seq *);
-extern gimple gimplify_body (tree *, tree, bool);
+extern gimple gimplify_body (tree, bool);
extern void push_gimplify_context (struct gimplify_ctx *);
extern void pop_gimplify_context (gimple);
extern void gimplify_and_add (tree, gimple_seq *);
Index: gimplify.c
===================================================================
--- gimplify.c (revision 182780)
+++ gimplify.c (working copy)
@@ -951,31 +951,33 @@ copy_if_shared_r (tree *tp, int *walk_su
/* Unshare most of the shared trees rooted at *TP. */
static inline void
-copy_if_shared (tree *tp)
+copy_if_shared (tree *tp, void *data)
{
- /* If the language requires deep unsharing, we need a pointer set to make
- sure we don't repeatedly unshare subtrees of unshareable nodes. */
- struct pointer_set_t *visited
- = lang_hooks.deep_unsharing ? pointer_set_create () : NULL;
- walk_tree (tp, copy_if_shared_r, visited, NULL);
- if (visited)
- pointer_set_destroy (visited);
+ walk_tree (tp, copy_if_shared_r, data, NULL);
}
-/* Unshare all the trees in BODY_P, a pointer into the body of FNDECL, and the
- bodies of any nested functions if we are unsharing the entire body of
- FNDECL. */
+/* Unshare all the trees in the body of FNDECL, as well as in the bodies of
+ any nested functions. */
static void
-unshare_body (tree *body_p, tree fndecl)
+unshare_body (tree fndecl)
{
struct cgraph_node *cgn = cgraph_get_node (fndecl);
+ /* If the language requires deep unsharing, we need a pointer set to make
+ sure we don't repeatedly unshare subtrees of unshareable nodes. */
+ struct pointer_set_t *visited
+ = lang_hooks.deep_unsharing ? pointer_set_create () : NULL;
- copy_if_shared (body_p);
+ copy_if_shared (&DECL_SAVED_TREE (fndecl), visited);
+ copy_if_shared (&DECL_SIZE (DECL_RESULT (fndecl)), visited);
+ copy_if_shared (&DECL_SIZE_UNIT (DECL_RESULT (fndecl)), visited);
+
+ if (visited)
+ pointer_set_destroy (visited);
- if (cgn && body_p == &DECL_SAVED_TREE (fndecl))
+ if (cgn)
for (cgn = cgn->nested; cgn; cgn = cgn->next_nested)
- unshare_body (&DECL_SAVED_TREE (cgn->decl), cgn->decl);
+ unshare_body (cgn->decl);
}
/* Callback for walk_tree to unmark the visited trees rooted at *TP.
@@ -1008,15 +1010,17 @@ unmark_visited (tree *tp)
/* Likewise, but mark all trees as not visited. */
static void
-unvisit_body (tree *body_p, tree fndecl)
+unvisit_body (tree fndecl)
{
struct cgraph_node *cgn = cgraph_get_node (fndecl);
- unmark_visited (body_p);
+ unmark_visited (&DECL_SAVED_TREE (fndecl));
+ unmark_visited (&DECL_SIZE (DECL_RESULT (fndecl)));
+ unmark_visited (&DECL_SIZE_UNIT (DECL_RESULT (fndecl)));
- if (cgn && body_p == &DECL_SAVED_TREE (fndecl))
+ if (cgn)
for (cgn = cgn->nested; cgn; cgn = cgn->next_nested)
- unvisit_body (&DECL_SAVED_TREE (cgn->decl), cgn->decl);
+ unvisit_body (cgn->decl);
}
/* Unconditionally make an unshared copy of EXPR. This is used when using
@@ -7932,13 +7936,12 @@ gimplify_one_sizepos (tree *expr_p, gimp
}
}
-/* Gimplify the body of statements pointed to by BODY_P and return a
- GIMPLE_BIND containing the sequence of GIMPLE statements
- corresponding to BODY_P. FNDECL is the function decl containing
- *BODY_P. */
+/* Gimplify the body of statements of FNDECL and return a GIMPLE_BIND node
+ containing the sequence of corresponding GIMPLE statements. If DO_PARMS
+ is true, also gimplify the parameters. */
gimple
-gimplify_body (tree *body_p, tree fndecl, bool do_parms)
+gimplify_body (tree fndecl, bool do_parms)
{
location_t saved_location = input_location;
gimple_seq parm_stmts, seq;
@@ -7959,8 +7962,8 @@ gimplify_body (tree *body_p, tree fndecl
It would seem we don't have to do this for nested functions because
they are supposed to be output and then the outer function gimplified
first, but the g++ front end doesn't always do it that way. */
- unshare_body (body_p, fndecl);
- unvisit_body (body_p, fndecl);
+ unshare_body (fndecl);
+ unvisit_body (fndecl);
cgn = cgraph_get_node (fndecl);
if (cgn && cgn->origin)
@@ -7971,11 +7974,11 @@ gimplify_body (tree *body_p, tree fndecl
/* Resolve callee-copies. This has to be done before processing
the body so that DECL_VALUE_EXPR gets processed correctly. */
- parm_stmts = (do_parms) ? gimplify_parameters () : NULL;
+ parm_stmts = do_parms ? gimplify_parameters () : NULL;
/* Gimplify the function's body. */
seq = NULL;
- gimplify_stmt (body_p, &seq);
+ gimplify_stmt (&DECL_SAVED_TREE (fndecl), &seq);
outer_bind = gimple_seq_first_stmt (seq);
if (!outer_bind)
{
@@ -7991,7 +7994,7 @@ gimplify_body (tree *body_p, tree fndecl
else
outer_bind = gimple_build_bind (NULL_TREE, seq, NULL);
- *body_p = NULL_TREE;
+ DECL_SAVED_TREE (fndecl) = NULL_TREE;
/* If we had callee-copies statements, insert them at the beginning
of the function and clear DECL_VALUE_EXPR_P on the parameters. */
@@ -8109,7 +8112,7 @@ gimplify_function_tree (tree fndecl)
&& !needs_to_live_in_memory (ret))
DECL_GIMPLE_REG_P (ret) = 1;
- bind = gimplify_body (&DECL_SAVED_TREE (fndecl), fndecl, true);
+ bind = gimplify_body (fndecl, true);
/* The tree body of the function is no longer needed, replace it
with the new GIMPLE body. */
Index: omp-low.c
===================================================================
--- omp-low.c (revision 182780)
+++ omp-low.c (working copy)
@@ -1248,7 +1248,7 @@ finalize_task_copyfn (gimple task_stmt)
old_fn = current_function_decl;
push_cfun (child_cfun);
current_function_decl = child_fn;
- bind = gimplify_body (&DECL_SAVED_TREE (child_fn), child_fn, false);
+ bind = gimplify_body (child_fn, false);
seq = gimple_seq_alloc ();
gimple_seq_add_stmt (&seq, bind);
new_seq = maybe_catch_exception (seq);
-- { dg-do compile }
package body Array19 is
function N return Integer is
begin
return 1;
end;
type Array_Type is array (1 .. N) of Float;
type Enum is (One, Two);
type Rec (D : Enum := Enum'First) is record
case D is
when One => null;
when Two => A : Array_Type;
end case;
end record;
procedure Proc is
R : Rec;
function F return Array_Type is
begin
return (others => 0.0);
end F;
begin
R.A := F;
end;
end Array19;
package Array19 is
procedure Proc;
end Array19;
