/* If either operand has side-effects, they have to be evaluated only once
in spite of the multiple references to the operand in the comparison. */
if (a1_side_effects_p)
- a1 = protect_multiple_eval (a1);
+ a1 = gnat_protect_expr (a1);
if (a2_side_effects_p)
- a2 = protect_multiple_eval (a2);
+ a2 = gnat_protect_expr (a2);
/* Process each dimension separately and compare the lengths. If any
dimension has a size known to be zero, set SIZE_ZERO_P to 1 to
/* For subtraction, add the modulus back if we are negative. */
else if (op_code == MINUS_EXPR)
{
- result = protect_multiple_eval (result);
+ result = gnat_protect_expr (result);
result = fold_build3 (COND_EXPR, op_type,
fold_build2 (LT_EXPR, integer_type_node, result,
convert (op_type, integer_zero_node)),
/* For the other operations, subtract the modulus if we are >= it. */
else
{
- result = protect_multiple_eval (result);
+ result = gnat_protect_expr (result);
result = fold_build3 (COND_EXPR, op_type,
fold_build2 (GE_EXPR, integer_type_node,
result, modulus),
{
/* Latch malloc's return value and get a pointer to the aligning field
first. */
- tree storage_ptr = protect_multiple_eval (malloc_ptr);
+ tree storage_ptr = gnat_protect_expr (malloc_ptr);
tree aligning_record_addr
= convert (build_pointer_type (aligning_type), storage_ptr);
storage = build_call_alloc_dealloc (NULL_TREE, size, storage_type,
gnat_proc, gnat_pool, gnat_node);
- storage = convert (storage_ptr_type, protect_multiple_eval (storage));
+ storage = convert (storage_ptr_type, gnat_protect_expr (storage));
if (TYPE_IS_PADDING_P (type))
{
and return the address with a COMPOUND_EXPR. */
if (init)
{
- result = protect_multiple_eval (result);
+ result = gnat_protect_expr (result);
result
= build2 (COMPOUND_EXPR, TREE_TYPE (result),
build_binary_op
return true;
}
}
+\f
+/* Save EXP for later use or reuse. This is equivalent to save_expr in tree.c
+ but we know how to handle our own nodes. */
+
+tree
+gnat_save_expr (tree exp)
+{
+ tree type = TREE_TYPE (exp);
+ enum tree_code code = TREE_CODE (exp);
+
+ if (TREE_CONSTANT (exp) || code == SAVE_EXPR || code == NULL_EXPR)
+ return exp;
+
+ if (code == UNCONSTRAINED_ARRAY_REF)
+ {
+ tree t = build1 (code, type, gnat_save_expr (TREE_OPERAND (exp, 0)));
+ TREE_READONLY (t) = TYPE_READONLY (type);
+ return t;
+ }
+
+ /* 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, gnat_save_expr (TREE_OPERAND (exp, 0)),
+ TREE_OPERAND (exp, 1), TREE_OPERAND (exp, 2));
+
+ return save_expr (exp);
+}
+
+/* Protect EXP for immediate reuse. This is a variant of gnat_save_expr that
+ is optimized under the assumption that EXP's value doesn't change before
+ its subsequent reuse(s) except through its potential reevaluation. */
+
+tree
+gnat_protect_expr (tree exp)
+{
+ tree type = TREE_TYPE (exp);
+ enum tree_code code = TREE_CODE (exp);
+
+ if (TREE_CONSTANT (exp) || code == SAVE_EXPR || code == NULL_EXPR)
+ return 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)
+ && !EXPRESSION_CLASS_P (skip_simple_arithmetic (exp)))
+ return exp;
+
+ /* If this is a conversion, protect what's inside the conversion. */
+ if (code == NON_LVALUE_EXPR
+ || CONVERT_EXPR_CODE_P (code)
+ || code == VIEW_CONVERT_EXPR)
+ return build1 (code, type, gnat_protect_expr (TREE_OPERAND (exp, 0)));
+
+ /* 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 == INDIRECT_REF || code == UNCONSTRAINED_ARRAY_REF)
+ {
+ tree t = build1 (code, type, gnat_protect_expr (TREE_OPERAND (exp, 0)));
+ TREE_READONLY (t) = TYPE_READONLY (type);
+ return t;
+ }
+
+ /* 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, gnat_protect_expr (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)));
+}
+
+/* This is equivalent to stabilize_reference_1 in tree.c but we take an extra
+ argument to force evaluation of 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 gnat_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;
+}
+
+/* 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
+gnat_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. */
+ if (success)
+ *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,
+ gnat_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,
+ gnat_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,
+ gnat_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,
+ gnat_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
+ {
+ if (success)
+ *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:
+ if (success)
+ *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;
+}
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