static tree extract_values (tree, tree);
static tree pos_to_constructor (Node_Id, tree, Entity_Id);
static tree maybe_implicit_deref (tree);
+static tree gnat_stabilize_reference (tree, bool);
+static tree gnat_stabilize_reference_1 (tree, bool);
static void set_expr_location_from_node (tree, Node_Id);
static int lvalue_required_p (Node_Id, tree, bool, bool);
if (Do_Range_Check (First (Expressions (gnat_node))))
{
- gnu_expr = gnat_protect_expr (gnu_expr);
+ gnu_expr = protect_multiple_eval (gnu_expr);
gnu_expr
= emit_check
(build_binary_op (EQ_EXPR, integer_type_node,
Present (gnat_when);
gnat_when = Next_Non_Pragma (gnat_when))
{
- bool choices_added_p = false;
Node_Id gnat_choice;
+ int choices_added = 0;
/* First compile all the different case choices for the current WHEN
alternative. */
gnu_low, gnu_high,
create_artificial_label (input_location)),
gnat_choice);
- choices_added_p = true;
+ choices_added++;
}
}
/* Push a binding level here in case variables are declared as we want
them to be local to this set of statements instead of to the block
containing the Case statement. */
- if (choices_added_p)
+ if (choices_added > 0)
{
add_stmt (build_stmt_group (Statements (gnat_when), true));
add_stmt (build1 (GOTO_EXPR, void_type_node,
??? This is more conservative than we need since we don't need to do
this for pass-by-ref with no conversion. */
if (Ekind (gnat_formal) != E_In_Parameter)
- gnu_name = gnat_stabilize_reference (gnu_name, true, NULL);
+ gnu_name = gnat_stabilize_reference (gnu_name, true);
/* If we are passing a non-addressable parameter by reference, pass the
address of a copy. In the Out or In Out case, set up to copy back
gnu_name_type)))
gnu_name = convert (gnu_name_type, gnu_name);
- /* Make a SAVE_EXPR to force the creation of a temporary. Special
- code in gnat_gimplify_expr ensures that the same temporary is
- used as the object and copied back after the call if needed. */
+ /* Make a SAVE_EXPR to both properly account for potential side
+ effects and handle the creation of a temporary. Special code
+ in gnat_gimplify_expr ensures that the same temporary is used
+ as the object and copied back after the call if needed. */
gnu_name = build1 (SAVE_EXPR, TREE_TYPE (gnu_name), gnu_name);
TREE_SIDE_EFFECTS (gnu_name) = 1;
gnu_expr, false, Is_Public (gnat_temp),
false, false, NULL, gnat_temp);
else
- gnu_expr = gnat_save_expr (gnu_expr);
+ gnu_expr = maybe_variable (gnu_expr);
save_gnu_tree (gnat_node, gnu_expr, true);
}
(TYPE_MAX_VALUE (gnu_base_index_type), gnu_result);
tree gnu_expr_l, gnu_expr_h, gnu_expr_type;
- gnu_min_expr = gnat_protect_expr (gnu_min_expr);
- gnu_max_expr = gnat_protect_expr (gnu_max_expr);
+ gnu_min_expr = protect_multiple_eval (gnu_min_expr);
+ gnu_max_expr = protect_multiple_eval (gnu_max_expr);
/* Derive a good type to convert everything to. */
gnu_expr_type = get_base_type (gnu_index_type);
? Designated_Type (Etype
(Prefix (gnat_node)))
: Etype (Prefix (gnat_node))))
- gnu_prefix = gnat_stabilize_reference (gnu_prefix, false, NULL);
+ gnu_prefix = gnat_stabilize_reference (gnu_prefix, false);
gnu_result
= build_component_ref (gnu_prefix, NULL_TREE, gnu_field,
else
{
tree t1, t2;
- gnu_obj = gnat_protect_expr (gnu_obj);
+ gnu_obj = protect_multiple_eval (gnu_obj);
t1 = build_binary_op (GE_EXPR, gnu_result_type, gnu_obj, gnu_low);
if (EXPR_P (t1))
set_expr_location_from_node (t1, gnat_node);
break;
case N_Null_Statement:
- /* When not optimizing, turn null statements from source into gotos to
- the next statement that the middle-end knows how to preserve. */
- if (!optimize && Comes_From_Source (gnat_node))
- {
- tree stmt, label = create_label_decl (NULL_TREE);
- start_stmt_group ();
- stmt = build1 (GOTO_EXPR, void_type_node, label);
- set_expr_location_from_node (stmt, gnat_node);
- add_stmt (stmt);
- stmt = build1 (LABEL_EXPR, void_type_node, label);
- set_expr_location_from_node (stmt, gnat_node);
- add_stmt (stmt);
- gnu_result = end_stmt_group ();
- }
- else
- gnu_result = alloc_stmt_list ();
+ gnu_result = alloc_stmt_list ();
break;
case N_Assignment_Statement:
if (TREE_SIDE_EFFECTS (gnu_result)
&& (TREE_CODE (gnu_result_type) == UNCONSTRAINED_ARRAY_TYPE
|| CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_result_type))))
- gnu_result = gnat_stabilize_reference (gnu_result, false, NULL);
+ gnu_result = gnat_stabilize_reference (gnu_result, false);
/* Now convert the result to the result type, unless we are in one of the
following cases:
{
gcc_assert (code == NEGATE_EXPR || code == ABS_EXPR);
- operand = gnat_protect_expr (operand);
+ operand = protect_multiple_eval (operand);
return emit_check (build_binary_op (EQ_EXPR, integer_type_node,
operand, TYPE_MIN_VALUE (gnu_type)),
build_binary_op_trapv (enum tree_code code, tree gnu_type, tree left,
tree right, Node_Id gnat_node)
{
- tree lhs = gnat_protect_expr (left);
- tree rhs = gnat_protect_expr (right);
+ tree lhs = protect_multiple_eval (left);
+ tree rhs = protect_multiple_eval (right);
tree type_max = TYPE_MAX_VALUE (gnu_type);
tree type_min = TYPE_MIN_VALUE (gnu_type);
tree gnu_expr;
return gnu_expr;
/* Checked expressions must be evaluated only once. */
- gnu_expr = gnat_protect_expr (gnu_expr);
+ gnu_expr = protect_multiple_eval (gnu_expr);
/* There's no good type to use here, so we might as well use
integer_type_node. Note that the form of the check is
tree gnu_expr_check;
/* Checked expressions must be evaluated only once. */
- gnu_expr = gnat_protect_expr (gnu_expr);
+ gnu_expr = protect_multiple_eval (gnu_expr);
/* Must do this computation in the base type in case the expression's
type is an unsigned subtypes. */
&& !(FLOAT_TYPE_P (gnu_base_type) && INTEGRAL_TYPE_P (gnu_in_basetype)))
{
/* Ensure GNU_EXPR only gets evaluated once. */
- tree gnu_input = gnat_protect_expr (gnu_result);
+ tree gnu_input = protect_multiple_eval (gnu_result);
tree gnu_cond = integer_zero_node;
tree gnu_in_lb = TYPE_MIN_VALUE (gnu_in_basetype);
tree gnu_in_ub = TYPE_MAX_VALUE (gnu_in_basetype);
conversion of the input to the calc_type (if necessary). */
gnu_zero = convert (gnu_in_basetype, integer_zero_node);
- gnu_result = gnat_protect_expr (gnu_result);
+ gnu_result = protect_multiple_eval (gnu_result);
gnu_conv = convert (calc_type, gnu_result);
gnu_comp
= fold_build2 (GE_EXPR, integer_type_node, gnu_result, gnu_zero);
return exp;
}
\f
+/* Protect EXP from multiple evaluation. This may make a SAVE_EXPR. */
+
+tree
+protect_multiple_eval (tree exp)
+{
+ tree type = TREE_TYPE (exp);
+ enum tree_code code = TREE_CODE (exp);
+
+ /* If EXP has no side effects, we theoritically don't need to do anything.
+ However, we may be recursively passed more and more complex expressions
+ involving checks which will be reused multiple times and eventually be
+ unshared for gimplification; in order to avoid a complexity explosion
+ at that point, we protect any expressions more complex than a simple
+ arithmetic expression. */
+ if (!TREE_SIDE_EFFECTS (exp)
+ && (CONSTANT_CLASS_P (exp)
+ || !EXPRESSION_CLASS_P (skip_simple_arithmetic (exp))))
+ return exp;
+
+ /* If this is a conversion, protect what's inside the conversion.
+ Similarly, if we're indirectly referencing something, we only
+ need to protect the address since the data itself can't change
+ in these situations. */
+ if (code == NON_LVALUE_EXPR
+ || CONVERT_EXPR_CODE_P (code)
+ || code == VIEW_CONVERT_EXPR
+ || code == INDIRECT_REF
+ || code == UNCONSTRAINED_ARRAY_REF)
+ return build1 (code, type, protect_multiple_eval (TREE_OPERAND (exp, 0)));
+
+ /* If this is a COMPONENT_REF of a fat pointer, save the entire fat pointer.
+ This may be more efficient, but will also allow us to more easily find
+ the match for the PLACEHOLDER_EXPR. */
+ if (code == COMPONENT_REF
+ && TYPE_IS_FAT_POINTER_P (TREE_TYPE (TREE_OPERAND (exp, 0))))
+ return build3 (code, type, protect_multiple_eval (TREE_OPERAND (exp, 0)),
+ TREE_OPERAND (exp, 1), TREE_OPERAND (exp, 2));
+
+ /* If this is a fat pointer or something that can be placed in a register,
+ just make a SAVE_EXPR. Likewise for a CALL_EXPR as large objects are
+ returned via invisible reference in most ABIs so the temporary will
+ directly be filled by the callee. */
+ if (TYPE_IS_FAT_POINTER_P (type)
+ || TYPE_MODE (type) != BLKmode
+ || code == CALL_EXPR)
+ return save_expr (exp);
+
+ /* Otherwise reference, protect the address and dereference. */
+ return
+ build_unary_op (INDIRECT_REF, type,
+ save_expr (build_unary_op (ADDR_EXPR,
+ build_reference_type (type),
+ exp)));
+}
+\f
+/* This is equivalent to stabilize_reference in tree.c, but we know how to
+ handle our own nodes and we take extra arguments. FORCE says whether to
+ force evaluation of everything. We set SUCCESS to true unless we walk
+ through something we don't know how to stabilize. */
+
+tree
+maybe_stabilize_reference (tree ref, bool force, bool *success)
+{
+ tree type = TREE_TYPE (ref);
+ enum tree_code code = TREE_CODE (ref);
+ tree result;
+
+ /* Assume we'll success unless proven otherwise. */
+ *success = true;
+
+ switch (code)
+ {
+ case CONST_DECL:
+ case VAR_DECL:
+ case PARM_DECL:
+ case RESULT_DECL:
+ /* No action is needed in this case. */
+ return ref;
+
+ case ADDR_EXPR:
+ CASE_CONVERT:
+ case FLOAT_EXPR:
+ case FIX_TRUNC_EXPR:
+ case VIEW_CONVERT_EXPR:
+ result
+ = build1 (code, type,
+ maybe_stabilize_reference (TREE_OPERAND (ref, 0), force,
+ success));
+ break;
+
+ case INDIRECT_REF:
+ case UNCONSTRAINED_ARRAY_REF:
+ result = build1 (code, type,
+ gnat_stabilize_reference_1 (TREE_OPERAND (ref, 0),
+ force));
+ break;
+
+ case COMPONENT_REF:
+ result = build3 (COMPONENT_REF, type,
+ maybe_stabilize_reference (TREE_OPERAND (ref, 0), force,
+ success),
+ TREE_OPERAND (ref, 1), NULL_TREE);
+ break;
+
+ case BIT_FIELD_REF:
+ result = build3 (BIT_FIELD_REF, type,
+ maybe_stabilize_reference (TREE_OPERAND (ref, 0), force,
+ success),
+ gnat_stabilize_reference_1 (TREE_OPERAND (ref, 1),
+ force),
+ gnat_stabilize_reference_1 (TREE_OPERAND (ref, 2),
+ force));
+ break;
+
+ case ARRAY_REF:
+ case ARRAY_RANGE_REF:
+ result = build4 (code, type,
+ maybe_stabilize_reference (TREE_OPERAND (ref, 0), force,
+ success),
+ gnat_stabilize_reference_1 (TREE_OPERAND (ref, 1),
+ force),
+ NULL_TREE, NULL_TREE);
+ break;
+
+ case CALL_EXPR:
+ case COMPOUND_EXPR:
+ result = gnat_stabilize_reference_1 (ref, force);
+ break;
+
+ case CONSTRUCTOR:
+ /* Constructors with 1 element are used extensively to formally
+ convert objects to special wrapping types. */
+ if (TREE_CODE (type) == RECORD_TYPE
+ && VEC_length (constructor_elt, CONSTRUCTOR_ELTS (ref)) == 1)
+ {
+ tree index
+ = VEC_index (constructor_elt, CONSTRUCTOR_ELTS (ref), 0)->index;
+ tree value
+ = VEC_index (constructor_elt, CONSTRUCTOR_ELTS (ref), 0)->value;
+ result
+ = build_constructor_single (type, index,
+ gnat_stabilize_reference_1 (value,
+ force));
+ }
+ else
+ {
+ *success = false;
+ return ref;
+ }
+ break;
+
+ case ERROR_MARK:
+ ref = error_mark_node;
+
+ /* ... fall through to failure ... */
+
+ /* If arg isn't a kind of lvalue we recognize, make no change.
+ Caller should recognize the error for an invalid lvalue. */
+ default:
+ *success = false;
+ return ref;
+ }
+
+ /* TREE_THIS_VOLATILE and TREE_SIDE_EFFECTS set on the initial expression
+ may not be sustained across some paths, such as the way via build1 for
+ INDIRECT_REF. We reset those flags here in the general case, which is
+ consistent with the GCC version of this routine.
+
+ Special care should be taken regarding TREE_SIDE_EFFECTS, because some
+ paths introduce side-effects where there was none initially (e.g. if a
+ SAVE_EXPR is built) and we also want to keep track of that. */
+ TREE_READONLY (result) = TREE_READONLY (ref);
+ TREE_SIDE_EFFECTS (result) |= TREE_SIDE_EFFECTS (ref);
+ TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (ref);
+
+ return result;
+}
+
+/* Wrapper around maybe_stabilize_reference, for common uses without lvalue
+ restrictions and without the need to examine the success indication. */
+
+static tree
+gnat_stabilize_reference (tree ref, bool force)
+{
+ bool dummy;
+ return maybe_stabilize_reference (ref, force, &dummy);
+}
+
+/* Similar to stabilize_reference_1 in tree.c, but supports an extra
+ arg to force a SAVE_EXPR for everything. */
+
+static tree
+gnat_stabilize_reference_1 (tree e, bool force)
+{
+ enum tree_code code = TREE_CODE (e);
+ tree type = TREE_TYPE (e);
+ tree result;
+
+ /* We cannot ignore const expressions because it might be a reference
+ to a const array but whose index contains side-effects. But we can
+ ignore things that are actual constant or that already have been
+ handled by this function. */
+ if (TREE_CONSTANT (e) || code == SAVE_EXPR)
+ return e;
+
+ switch (TREE_CODE_CLASS (code))
+ {
+ case tcc_exceptional:
+ case tcc_declaration:
+ case tcc_comparison:
+ case tcc_expression:
+ case tcc_reference:
+ case tcc_vl_exp:
+ /* If this is a COMPONENT_REF of a fat pointer, save the entire
+ fat pointer. This may be more efficient, but will also allow
+ us to more easily find the match for the PLACEHOLDER_EXPR. */
+ if (code == COMPONENT_REF
+ && TYPE_IS_FAT_POINTER_P (TREE_TYPE (TREE_OPERAND (e, 0))))
+ result
+ = build3 (code, type,
+ gnat_stabilize_reference_1 (TREE_OPERAND (e, 0), force),
+ TREE_OPERAND (e, 1), TREE_OPERAND (e, 2));
+ /* If the expression has side-effects, then encase it in a SAVE_EXPR
+ so that it will only be evaluated once. */
+ /* The tcc_reference and tcc_comparison classes could be handled as
+ below, but it is generally faster to only evaluate them once. */
+ else if (TREE_SIDE_EFFECTS (e) || force)
+ return save_expr (e);
+ else
+ return e;
+ break;
+
+ case tcc_binary:
+ /* Recursively stabilize each operand. */
+ result
+ = build2 (code, type,
+ gnat_stabilize_reference_1 (TREE_OPERAND (e, 0), force),
+ gnat_stabilize_reference_1 (TREE_OPERAND (e, 1), force));
+ break;
+
+ case tcc_unary:
+ /* Recursively stabilize each operand. */
+ result
+ = build1 (code, type,
+ gnat_stabilize_reference_1 (TREE_OPERAND (e, 0), force));
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+
+ /* See similar handling in maybe_stabilize_reference. */
+ TREE_READONLY (result) = TREE_READONLY (e);
+ TREE_SIDE_EFFECTS (result) |= TREE_SIDE_EFFECTS (e);
+ TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (e);
+
+ return result;
+}
+\f
/* Convert SLOC into LOCUS. Return true if SLOC corresponds to a source code
location and false if it doesn't. In the former case, set the Gigi global
variable REF_FILENAME to the simple debug file name as given by sinput. */
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