}
/* Process the final expression of a statement expression. EXPR can be
- NULL, if the final expression is empty. Build up a TARGET_EXPR so
- that the result value can be safely returned to the enclosing
- expression. */
+ NULL, if the final expression is empty. Return a STATEMENT_LIST
+ containing all the statements in the statement-expression, or
+ ERROR_MARK_NODE if there was an error. */
tree
finish_stmt_expr_expr (tree expr, tree stmt_expr)
{
- tree result = NULL_TREE;
-
if (error_operand_p (expr))
return error_mark_node;
+ /* If the last statement does not have "void" type, then the value
+ of the last statement is the value of the entire expression. */
if (expr)
{
- if (!processing_template_decl && !VOID_TYPE_P (TREE_TYPE (expr)))
+ tree type;
+ type = TREE_TYPE (expr);
+ if (!dependent_type_p (type) && !VOID_TYPE_P (type))
{
- tree type = TREE_TYPE (expr);
-
- if (TREE_CODE (type) == ARRAY_TYPE
- || TREE_CODE (type) == FUNCTION_TYPE)
- expr = decay_conversion (expr);
-
- expr = require_complete_type (expr);
-
+ expr = decay_conversion (expr);
+ if (error_operand_p (expr))
+ return error_mark_node;
type = TREE_TYPE (expr);
-
- /* Build a TARGET_EXPR for this aggregate. finish_stmt_expr
- will then pull it apart so the lifetime of the target is
- within the scope of the expression containing this statement
- expression. */
- if (TREE_CODE (expr) == TARGET_EXPR)
- ;
- else if (!IS_AGGR_TYPE (type) || TYPE_HAS_TRIVIAL_INIT_REF (type))
- expr = build_target_expr_with_type (expr, type);
+ }
+ /* The type of the statement-expression is the type of the last
+ expression. */
+ TREE_TYPE (stmt_expr) = type;
+ /* We must take particular care if TYPE is a class type. In
+ paticular if EXPR creates a temporary of class type, then it
+ must be destroyed at the semicolon terminating the last
+ statement -- but we must make a copy before that happens.
+
+ This problem is solved by using a TARGET_EXPR to initialize a
+ new temporary variable. The TARGET_EXPR itself is placed
+ outside the statement-expression. However, the last
+ statement in the statement-expression is transformed from
+ EXPR to (approximately) T = EXPR, where T is the new
+ temporary variable. Thus, the lifetime of the new temporary
+ extends to the full-expression surrounding the
+ statement-expression. */
+ if (!processing_template_decl && !VOID_TYPE_P (type))
+ {
+ tree target_expr;
+ if (CLASS_TYPE_P (type)
+ && !TYPE_HAS_TRIVIAL_INIT_REF (type))
+ {
+ target_expr = build_target_expr_with_type (expr, type);
+ expr = TARGET_EXPR_INITIAL (target_expr);
+ }
else
{
- /* Copy construct. */
- expr = build_special_member_call
- (NULL_TREE, complete_ctor_identifier,
- build_tree_list (NULL_TREE, expr),
- type, LOOKUP_NORMAL);
- expr = build_cplus_new (type, expr);
- gcc_assert (TREE_CODE (expr) == TARGET_EXPR);
+ /* Normally, build_target_expr will not create a
+ TARGET_EXPR for scalars. However, we need the
+ temporary here, in order to solve the scoping
+ problem described above. */
+ target_expr = force_target_expr (type, expr);
+ expr = TARGET_EXPR_INITIAL (target_expr);
+ expr = build2 (INIT_EXPR,
+ type,
+ TARGET_EXPR_SLOT (target_expr),
+ expr);
}
- }
-
- if (expr != error_mark_node)
- {
- result = build_stmt (EXPR_STMT, expr);
- EXPR_STMT_STMT_EXPR_RESULT (result) = 1;
- add_stmt (result);
+ TARGET_EXPR_INITIAL (target_expr) = NULL_TREE;
+ /* Save away the TARGET_EXPR in the TREE_TYPE field of the
+ STATEMENT_EXPR. We will retrieve it in
+ finish_stmt_expr. */
+ TREE_TYPE (stmt_expr) = target_expr;
}
}
- finish_stmt ();
+ /* Having modified EXPR to reflect the extra initialization, we now
+ treat it just like an ordinary statement. */
+ expr = finish_expr_stmt (expr);
- /* Remember the last expression so that finish_stmt_expr
- can pull it apart. */
- TREE_TYPE (stmt_expr) = result;
+ /* Mark the last statement so that we can recognize it as such at
+ template-instantiation time. */
+ if (expr && processing_template_decl)
+ EXPR_STMT_STMT_EXPR_RESULT (expr) = 1;
- return result;
+ return stmt_expr;
}
/* Finish a statement-expression. EXPR should be the value returned
tree
finish_stmt_expr (tree stmt_expr, bool has_no_scope)
{
- tree result, result_stmt, type;
- tree *result_stmt_p = NULL;
+ tree type;
+ tree result;
- result_stmt = TREE_TYPE (stmt_expr);
- TREE_TYPE (stmt_expr) = void_type_node;
- result = pop_stmt_list (stmt_expr);
+ if (error_operand_p (stmt_expr))
+ return error_mark_node;
- if (!result_stmt || VOID_TYPE_P (result_stmt))
- type = void_type_node;
- else
- {
- /* We need to search the statement expression for the result_stmt,
- since we'll need to replace it entirely. */
- tree t;
- result_stmt_p = &result;
- while (1)
- {
- t = *result_stmt_p;
- if (t == result_stmt)
- break;
+ gcc_assert (TREE_CODE (stmt_expr) == STATEMENT_LIST);
- switch (TREE_CODE (t))
- {
- case STATEMENT_LIST:
- {
- tree_stmt_iterator i = tsi_last (t);
- result_stmt_p = tsi_stmt_ptr (i);
- break;
- }
- case BIND_EXPR:
- result_stmt_p = &BIND_EXPR_BODY (t);
- break;
- case TRY_FINALLY_EXPR:
- case TRY_CATCH_EXPR:
- case CLEANUP_STMT:
- result_stmt_p = &TREE_OPERAND (t, 0);
- break;
- default:
- gcc_unreachable ();
- }
- }
- type = TREE_TYPE (EXPR_STMT_EXPR (result_stmt));
- }
+ type = TREE_TYPE (stmt_expr);
+ result = pop_stmt_list (stmt_expr);
if (processing_template_decl)
{
TREE_SIDE_EFFECTS (result) = 1;
STMT_EXPR_NO_SCOPE (result) = has_no_scope;
}
- else if (!VOID_TYPE_P (type))
+ else if (!TYPE_P (type))
{
- /* Pull out the TARGET_EXPR that is the final expression. Put
- the target's init_expr as the final expression and then put
- the statement expression itself as the target's init
- expr. Finally, return the target expression. */
- tree init, target_expr = EXPR_STMT_EXPR (result_stmt);
- gcc_assert (TREE_CODE (target_expr) == TARGET_EXPR);
-
- /* The initializer will be void if the initialization is done by
- AGGR_INIT_EXPR; propagate that out to the statement-expression as
- a whole. */
- init = TREE_OPERAND (target_expr, 1);
- type = TREE_TYPE (init);
-
- init = maybe_cleanup_point_expr (init);
- *result_stmt_p = init;
-
- if (VOID_TYPE_P (type))
- /* No frobbing needed. */;
- else if (TREE_CODE (result) == BIND_EXPR)
- {
- /* The BIND_EXPR created in finish_compound_stmt is void; if we're
- returning a value directly, give it the appropriate type. */
- if (VOID_TYPE_P (TREE_TYPE (result)))
- TREE_TYPE (result) = type;
- else
- gcc_assert (same_type_p (TREE_TYPE (result), type));
- }
- else if (TREE_CODE (result) == STATEMENT_LIST)
- /* We need to wrap a STATEMENT_LIST in a BIND_EXPR so it can have a
- type other than void. FIXME why can't we just return a value
- from STATEMENT_LIST? */
- result = build3 (BIND_EXPR, type, NULL, result, NULL);
-
- TREE_OPERAND (target_expr, 1) = result;
- result = target_expr;
+ gcc_assert (TREE_CODE (type) == TARGET_EXPR);
+ TARGET_EXPR_INITIAL (type) = result;
+ TREE_TYPE (result) = void_type_node;
+ result = type;
}
return result;
OSDN Git Service
