return GS_OK;
}
+/* A subroutine of gimplify_init_ctor_preeval. Called via walk_tree,
+ determine, cautiously, if a CONSTRUCTOR overlaps the lhs of an
+ assignment. Returns non-null if we detect a potential overlap. */
+
+struct gimplify_init_ctor_preeval_data
+{
+ /* The base decl of the lhs object. May be NULL, in which case we
+ have to assume the lhs is indirect. */
+ tree lhs_base_decl;
+
+ /* The alias set of the lhs object. */
+ int lhs_alias_set;
+};
+
+static tree
+gimplify_init_ctor_preeval_1 (tree *tp, int *walk_subtrees, void *xdata)
+{
+ struct gimplify_init_ctor_preeval_data *data
+ = (struct gimplify_init_ctor_preeval_data *) xdata;
+ tree t = *tp;
+
+ /* If we find the base object, obviously we have overlap. */
+ if (data->lhs_base_decl == t)
+ return t;
+
+ /* If the constructor component is indirect, determine if we have a
+ potential overlap with the lhs. The only bits of information we
+ have to go on at this point are addressability and alias sets. */
+ if (TREE_CODE (t) == INDIRECT_REF
+ && (!data->lhs_base_decl || TREE_ADDRESSABLE (data->lhs_base_decl))
+ && alias_sets_conflict_p (data->lhs_alias_set, get_alias_set (t)))
+ return t;
+
+ if (DECL_P (t) || TYPE_P (t))
+ *walk_subtrees = 0;
+ return NULL;
+}
+
+/* A subroutine of gimplify_init_constructor. Pre-evaluate *EXPR_P,
+ force values that overlap with the lhs (as described by *DATA)
+ into temporaries. */
+
+static void
+gimplify_init_ctor_preeval (tree *expr_p, tree *pre_p, tree *post_p,
+ struct gimplify_init_ctor_preeval_data *data)
+{
+ enum gimplify_status one;
+
+ /* If the value is invariant, then there's nothing to pre-evaluate.
+ But ensure it doesn't have any side-effects since a SAVE_EXPR is
+ invariant but has side effects and might contain a reference to
+ the object we're initializing. */
+ if (TREE_INVARIANT (*expr_p) && !TREE_SIDE_EFFECTS (*expr_p))
+ return;
+
+ /* If the type has non-trivial constructors, we can't pre-evaluate. */
+ if (TREE_ADDRESSABLE (TREE_TYPE (*expr_p)))
+ return;
+
+ /* Recurse for nested constructors. */
+ if (TREE_CODE (*expr_p) == CONSTRUCTOR)
+ {
+ tree list;
+ for (list = CONSTRUCTOR_ELTS (*expr_p); list ; list = TREE_CHAIN (list))
+ gimplify_init_ctor_preeval (&TREE_VALUE (list), pre_p, post_p, data);
+ return;
+ }
+
+ /* We can't preevaluate if the type contains a placeholder. */
+ if (type_contains_placeholder_p (TREE_TYPE (*expr_p)))
+ return;
+
+ /* Gimplify the constructor element to something appropriate for the rhs
+ of a MODIFY_EXPR. Given that we know the lhs is an aggregate, we know
+ the gimplifier will consider this a store to memory. Doing this
+ gimplification now means that we won't have to deal with complicated
+ language-specific trees, nor trees like SAVE_EXPR that can induce
+ exponential search behaviour. */
+ one = gimplify_expr (expr_p, pre_p, post_p, is_gimple_mem_rhs, fb_rvalue);
+ if (one == GS_ERROR)
+ {
+ *expr_p = NULL;
+ return;
+ }
+
+ /* If we gimplified to a bare decl, we can be sure that it doesn't overlap
+ with the lhs, since "a = { .x=a }" doesn't make sense. This will
+ always be true for all scalars, since is_gimple_mem_rhs insists on a
+ temporary variable for them. */
+ if (DECL_P (*expr_p))
+ return;
+
+ /* If this is of variable size, we have no choice but to assume it doesn't
+ overlap since we can't make a temporary for it. */
+ if (!TREE_CONSTANT (TYPE_SIZE (TREE_TYPE (*expr_p))))
+ return;
+
+ /* Otherwise, we must search for overlap ... */
+ if (!walk_tree (expr_p, gimplify_init_ctor_preeval_1, data, NULL))
+ return;
+
+ /* ... and if found, force the value into a temporary. */
+ *expr_p = get_formal_tmp_var (*expr_p, pre_p);
+}
+
+/* A subroutine of gimplify_init_constructor. Generate individual
+ MODIFY_EXPRs for a CONSTRUCTOR. OBJECT is the LHS against which the
+ assignments should happen. LIST is the CONSTRUCTOR_ELTS of the
+ CONSTRUCTOR. CLEARED is true if the entire LHS object has been
+ zeroed first. */
+
+static void
+gimplify_init_ctor_eval (tree object, tree list, tree *pre_p, bool cleared)
+{
+ tree array_elt_type = NULL;
+
+ if (TREE_CODE (TREE_TYPE (object)) == ARRAY_TYPE)
+ array_elt_type = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (object)));
+
+ for (; list; list = TREE_CHAIN (list))
+ {
+ tree purpose, value, cref, init;
+
+ purpose = TREE_PURPOSE (list);
+ value = TREE_VALUE (list);
+
+ /* NULL values are created above for gimplification errors. */
+ if (value == NULL)
+ continue;
+
+ if (cleared && initializer_zerop (value))
+ continue;
+
+ if (array_elt_type)
+ {
+ /* ??? Here's to hoping the front end fills in all of the indicies,
+ so we don't have to figure out what's missing ourselves. */
+ if (!purpose)
+ abort ();
+ /* ??? Need to handle this. */
+ if (TREE_CODE (purpose) == RANGE_EXPR)
+ abort ();
+
+ cref = build (ARRAY_REF, array_elt_type, unshare_expr (object),
+ purpose, NULL_TREE, NULL_TREE);
+ }
+ else
+ cref = build (COMPONENT_REF, TREE_TYPE (purpose),
+ unshare_expr (object), purpose, NULL_TREE);
+
+ if (TREE_CODE (value) == CONSTRUCTOR)
+ gimplify_init_ctor_eval (cref, CONSTRUCTOR_ELTS (value),
+ pre_p, cleared);
+ else
+ {
+ init = build (MODIFY_EXPR, TREE_TYPE (cref), cref, value);
+ gimplify_and_add (init, pre_p);
+ }
+ }
+}
+
/* A subroutine of gimplify_modify_expr. Break out elements of a
CONSTRUCTOR used as an initializer into separate MODIFY_EXPRs.
gimplify_init_constructor (tree *expr_p, tree *pre_p,
tree *post_p, bool want_value)
{
- tree object = TREE_OPERAND (*expr_p, 0);
+ tree object;
tree ctor = TREE_OPERAND (*expr_p, 1);
tree type = TREE_TYPE (ctor);
enum gimplify_status ret;
if (TREE_CODE (ctor) != CONSTRUCTOR)
return GS_UNHANDLED;
+ ret = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p, post_p,
+ is_gimple_lvalue, fb_lvalue);
+ if (ret == GS_ERROR)
+ return ret;
+ object = TREE_OPERAND (*expr_p, 0);
+
elt_list = CONSTRUCTOR_ELTS (ctor);
ret = GS_ALL_DONE;
case QUAL_UNION_TYPE:
case ARRAY_TYPE:
{
- HOST_WIDE_INT i, num_elements, num_nonzero_elements;
+ struct gimplify_init_ctor_preeval_data preeval_data;
+ HOST_WIDE_INT num_elements, num_nonzero_elements;
HOST_WIDE_INT num_nonconstant_elements;
bool cleared;
individual elements. The exception is that a CONSTRUCTOR node
with no elements indicates zero-initialization of the whole. */
if (elt_list == NULL)
- {
- if (want_value)
- {
- *expr_p = object;
- return GS_OK;
- }
- else
- return GS_UNHANDLED;
- }
+ break;
categorize_ctor_elements (ctor, &num_nonzero_elements,
&num_nonconstant_elements);
- num_elements = count_type_elements (TREE_TYPE (ctor));
/* If a const aggregate variable is being initialized, then it
should never be a lose to promote the variable to be static. */
if (size > 0 && !can_move_by_pieces (size, align))
{
tree new = create_tmp_var_raw (type, "C");
+
gimple_add_tmp_var (new);
TREE_STATIC (new) = 1;
TREE_READONLY (new) = 1;
walk_tree (&DECL_INITIAL (new), force_labels_r, NULL, NULL);
TREE_OPERAND (*expr_p, 1) = new;
- break;
+
+ /* This is no longer an assignment of a CONSTRUCTOR, but
+ we still may have processing to do on the LHS. So
+ pretend we didn't do anything here to let that happen. */
+ return GS_UNHANDLED;
}
}
parts in, then generate code for the non-constant parts. */
/* TODO. There's code in cp/typeck.c to do this. */
+ num_elements = count_type_elements (TREE_TYPE (ctor));
+
/* If there are "lots" of zeros, then block clear the object first. */
cleared = false;
if (num_elements - num_nonzero_elements > CLEAR_RATIO
tree nelts = array_type_nelts (type);
if (!host_integerp (nelts, 1)
|| tree_low_cst (nelts, 1) + 1 != len)
- cleared = 1;;
+ cleared = true;
}
else if (len != fields_length (type))
- cleared = 1;
+ cleared = true;
}
if (cleared)
{
/* Zap the CONSTRUCTOR element list, which simplifies this case.
Note that we still have to gimplify, in order to handle the
- case of variable sized types. Make an unshared copy of
- OBJECT before that so we can match a PLACEHOLDER_EXPR to it
- later, if needed. */
+ case of variable sized types. Avoid shared tree structures. */
CONSTRUCTOR_ELTS (ctor) = NULL_TREE;
- object = unshare_expr (TREE_OPERAND (*expr_p, 0));
+ object = unshare_expr (object);
gimplify_stmt (expr_p);
append_to_statement_list (*expr_p, pre_p);
}
- for (i = 0; elt_list; i++, elt_list = TREE_CHAIN (elt_list))
- {
- tree purpose, value, cref, init;
-
- purpose = TREE_PURPOSE (elt_list);
- value = TREE_VALUE (elt_list);
-
- if (cleared && initializer_zerop (value))
- continue;
+ preeval_data.lhs_base_decl = get_base_address (object);
+ if (!DECL_P (preeval_data.lhs_base_decl))
+ preeval_data.lhs_base_decl = NULL;
+ preeval_data.lhs_alias_set = get_alias_set (object);
- if (TREE_CODE (type) == ARRAY_TYPE)
- {
- tree t = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (object)));
-
- /* ??? Here's to hoping the front end fills in all of the
- indicies, so we don't have to figure out what's missing
- ourselves. */
- if (!purpose)
- abort ();
- /* ??? Need to handle this. */
- if (TREE_CODE (purpose) == RANGE_EXPR)
- abort ();
-
- cref = build (ARRAY_REF, t, unshare_expr (object), purpose,
- NULL_TREE, NULL_TREE);
- }
- else
- cref = build (COMPONENT_REF, TREE_TYPE (purpose),
- unshare_expr (object), purpose, NULL_TREE);
-
- init = build (MODIFY_EXPR, TREE_TYPE (purpose), cref, value);
-
- /* Each member initialization is a full-expression. */
- gimplify_and_add (init, pre_p);
- }
+ gimplify_init_ctor_preeval (&TREE_OPERAND (*expr_p, 1),
+ pre_p, post_p, &preeval_data);
+ gimplify_init_ctor_eval (object, elt_list, pre_p, cleared);
*expr_p = NULL_TREE;
}
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