2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Lowering of Calls with compound parameters and return types.
23 * @author Michael Beck
26 #ifndef FIRM_LOWER_LOWER_CALLS_H
27 #define FIRM_LOWER_LOWER_CALLS_H
30 * A type telling where to add hidden parameters.
32 typedef enum add_hidden_params {
33 ADD_HIDDEN_ALWAYS_IN_FRONT = 0, /**< always add hidden parameters in front (default). */
34 ADD_HIDDEN_ALWAYS_LAST = 1, /**< always add hidden parameters last, did not work for variadic functions. */
35 ADD_HIDDEN_SMART = 2 /**< add hidden parameters last for non-variadic and first for variadic functions. */
39 * Additional flags for the lowering.
42 LF_NONE = 0, /**< no additional flags */
43 LF_COMPOUND_PARAM = 1, /**< lower calls with compound parameters */
44 LF_COMPOUND_RETURN = 2, /**< lower calls with compound returns */
45 LF_RETURN_HIDDEN = 4, /**< return the hidden address instead of void */
46 LF_SMALL_CMP_IN_REGS = 8 /**< return small compound values in registers */
49 /** Maximum number of registers that can be used to return compound values. */
50 #define MAX_REGISTER_RET_VAL 2
53 * A struct containing all control parameters for
54 * lower_compound_ret_calls().
57 int def_ptr_alignment; /**< Default alignment for data pointer. */
58 unsigned flags; /**< A bitmask of enum lowering_flags. */
59 add_hidden hidden_params; /**< Where to add hidden parameters. */
62 * A function returning a pointer type for a given type.
63 * If this pointer is NULL, a new pointer type is always created.
65 ir_type *(*find_pointer_type)(ir_type *e_type, ir_mode *mode, int alignment);
68 * If the LF_SMALL_CMP_IN_REGS flag is set, this function will be called
69 * to decide, whether a compound value should be returned in registers.
70 * This function must return the number of used registers and fill in the modes
71 * of the registers to use. Up to MAX_REGISTER_RET_VAL registers can be used.
73 int (*ret_compound_in_regs)(ir_type *compound_tp, ir_mode **modes);
77 * Lower calls with compound parameter and return types.
78 * This function does the following transformations:
80 * If LF_COMPOUND_PARAM is set:
82 * - Copy compound parameters to a new location on the callers
83 * stack and transmit the address of this new location
85 * If LF_COMPOUND_RETURN is set:
87 * - Adds a new (hidden) pointer parameter for
88 * any return compound type. The return type is replaced by void
89 * or if LOWERING_FLAGS_RETURN_HIDDEN is set by the address.
91 * - Use of the hidden parameters in the function code.
93 * - Change all calls to functions with compound return
94 * by providing space for the hidden parameter on the callers
97 * - Replace a possible block copy after the function call.
101 * - Changes the types of methods and calls to the lowered ones
103 * - lower all method types of existing entities
105 * In pseudo-code, the following transformation is done:
108 struct x ret = func(a, b);
117 * If the function returns only one possible result, the copy-on-return
118 * optimization is done, ie.
127 * is transformed into
130 void func(struct x *ret, a) {
135 * @param params A structure containing the control parameter for this
138 * During the transformation, pointer types must be created or reused.
139 * The caller can provide params->find_pointer_type for this task to
140 * reduce the number of created pointer types.
141 * If params->find_pointer_type is NULL, new pointer types
142 * are always created automatically.
144 void lower_calls_with_compounds(const lower_params_t *params);
146 #endif /* FIRM_LOWER_LOWER_CALLS_H */