From 9582a3cd55cfe9218f3fd8c80808d816c8774897 Mon Sep 17 00:00:00 2001 From: Olivier Hainque Date: Fri, 9 Dec 2005 18:16:11 +0100 Subject: [PATCH] decl.c (gnat_to_gnu_entity, [...]): Don't early expand pointer initialization values. 2005-12-05 Olivier Hainque * decl.c (gnat_to_gnu_entity, renaming object case): Don't early expand pointer initialization values. Make a SAVE_EXPR instead. Add comments about the use and expansion of SAVE_EXPRs in the various possible renaming handling cases. (components_to_record, compare_field_bitpos): Sort by DECL_UID, not by abusing DECL_FCONTEXT. From-SVN: r108286 --- gcc/ada/decl.c | 93 +++++++++++++++++++++++++++----------------------- 1 file changed, 50 insertions(+), 43 deletions(-) diff --git a/gcc/ada/decl.c b/gcc/ada/decl.c index bbbb471a3ae..b64463a53b6 100644 --- a/gcc/ada/decl.c +++ b/gcc/ada/decl.c @@ -765,14 +765,16 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition) the renamed entity or if we need to make a pointer. */ else { - bool stabilized; + bool stabilized = false; tree maybe_stable_expr = NULL_TREE; /* Case 2: If the renaming entity need not be materialized and the renamed expression is something we can stabilize, use - that for the renaming after forcing the evaluation of any - SAVE_EXPR. At the global level, we can only do this if we - know no SAVE_EXPRs will be made. */ + that for the renaming. At the global level, we can only do + this if we know no SAVE_EXPRs need be made, because the + expression we return might be used in arbitrary conditional + branches so we must force the SAVE_EXPRs evaluation + immediately and this requires a function context. */ if (!Materialize_Entity (gnat_entity) && (!global_bindings_p () || (staticp (gnu_expr) @@ -812,21 +814,35 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition) object, we just make a "bare" pointer, and the renamed entity is always accessed indirectly through it. */ { - bool has_side_effects = TREE_SIDE_EFFECTS (gnu_expr); + bool expr_has_side_effects = TREE_SIDE_EFFECTS (gnu_expr); + inner_const_flag = TREE_READONLY (gnu_expr); const_flag = true; gnu_type = build_reference_type (gnu_type); - /* If a previous attempt at unrestricted - stabilization failed, there is no point trying - again and we can reuse the result without - attaching it to the pointer. */ + /* If a previous attempt at unrestricted stabilization + failed, there is no point trying again and we can reuse + the result without attaching it to the pointer. */ if (maybe_stable_expr) ; /* Otherwise, try to stabilize now, restricting to lvalues only, and attach the expression to the pointer - if the stabilization succeeds. */ + if the stabilization succeeds. + + Note that this might introduce SAVE_EXPRs and we don't + check whether we're at the global level or not. This is + fine since we are building a pointer initializer and + neither the pointer nor the initializing expression can + be accessed before the pointer elaboration has taken + place in a correct program. + + SAVE_EXPRs will be evaluated at the right spots by either + create_var_decl->expand_decl_init for the non-global case + or build_unit_elab for the global case, and will be + attached to the elaboration procedure by the RTL expander + in the latter case. We have no need to force an early + evaluation here. */ else { maybe_stable_expr @@ -842,15 +858,13 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition) gnu_expr = build_unary_op (ADDR_EXPR, gnu_type, maybe_stable_expr); - if (!global_bindings_p ()) - { - /* If the original expression had side effects, put a - SAVE_EXPR around this whole thing. */ - if (has_side_effects) - gnu_expr = save_expr (gnu_expr); - - add_stmt (gnu_expr); - } + /* If the initial expression has side effects, we might + still have an unstabilized version at this point (for + instance if it involves a function call). Wrap the + result into a SAVE_EXPR now, in case it happens to be + referenced several times. */ + if (expr_has_side_effects && ! stabilized) + gnu_expr = save_expr (gnu_expr); gnu_size = NULL_TREE; used_by_ref = true; @@ -1001,16 +1015,16 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition) gnu_alloc_type = TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (gnu_alloc_type))); - if (TREE_CODE (gnu_expr) == CONSTRUCTOR - && VEC_length (constructor_elt, - CONSTRUCTOR_ELTS (gnu_expr)) == 1) - gnu_expr = 0; - else - gnu_expr - = build_component_ref - (gnu_expr, NULL_TREE, - TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (gnu_expr))), - false); + if (TREE_CODE (gnu_expr) == CONSTRUCTOR + && 1 == VEC_length (constructor_elt, + CONSTRUCTOR_ELTS (gnu_expr))) + gnu_expr = 0; + else + gnu_expr + = build_component_ref + (gnu_expr, NULL_TREE, + TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (gnu_expr))), + false); } if (TREE_CODE (TYPE_SIZE_UNIT (gnu_alloc_type)) == INTEGER_CST @@ -5676,27 +5690,22 @@ components_to_record (tree gnu_record_type, Node_Id component_list, /* If we have any items in our rep'ed field list, it is not the case that all the fields in the record have rep clauses, and P_REP_LIST is nonzero, - set it and ignore the items. Otherwise, sort the fields by bit position - and put them into their own record if we have any fields without - rep clauses. */ + set it and ignore the items. */ if (gnu_our_rep_list && p_gnu_rep_list && !all_rep) *p_gnu_rep_list = chainon (*p_gnu_rep_list, gnu_our_rep_list); else if (gnu_our_rep_list) { + /* Otherwise, sort the fields by bit position and put them into their + own record if we have any fields without rep clauses. */ tree gnu_rep_type = (gnu_field_list ? make_node (RECORD_TYPE) : gnu_record_type); int len = list_length (gnu_our_rep_list); tree *gnu_arr = (tree *) alloca (sizeof (tree) * len); int i; - /* Set/abuse DECL_FCONTEXT to increasing integers so we have a - stable sort. */ for (i = 0, gnu_field = gnu_our_rep_list; gnu_field; gnu_field = TREE_CHAIN (gnu_field), i++) - { - gnu_arr[i] = gnu_field; - DECL_FCONTEXT (gnu_field) = size_int (i); - } + gnu_arr[i] = gnu_field; qsort (gnu_arr, len, sizeof (tree), compare_field_bitpos); @@ -5708,7 +5717,6 @@ components_to_record (tree gnu_record_type, Node_Id component_list, TREE_CHAIN (gnu_arr[i]) = gnu_our_rep_list; gnu_our_rep_list = gnu_arr[i]; DECL_CONTEXT (gnu_arr[i]) = gnu_rep_type; - DECL_FCONTEXT (gnu_arr[i]) = NULL_TREE; } if (gnu_field_list) @@ -5734,7 +5742,8 @@ components_to_record (tree gnu_record_type, Node_Id component_list, } /* Called via qsort from the above. Returns -1, 1, depending on the - bit positions and ordinals of the two fields. */ + bit positions and ordinals of the two fields. Use DECL_UID to ensure + a stable sort. */ static int compare_field_bitpos (const PTR rt1, const PTR rt2) @@ -5743,9 +5752,7 @@ compare_field_bitpos (const PTR rt1, const PTR rt2) tree *t2 = (tree *) rt2; if (tree_int_cst_equal (bit_position (*t1), bit_position (*t2))) - return - (tree_int_cst_lt (DECL_FCONTEXT (*t1), DECL_FCONTEXT (*t2)) - ? -1 : 1); + return DECL_UID (*t1) < DECL_UID (*t2) ? -1 : 1; else if (tree_int_cst_lt (bit_position (*t1), bit_position (*t2))) return -1; else