bestack: Fetch the start block only once.
[libfirm] / ir / be / beinsn.c
1 /*
2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
3  *
4  * This file is part of libFirm.
5  *
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.
10  *
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.
14  *
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
17  * PURPOSE.
18  */
19
20 /**
21  * @file
22  * @brief       A data structure to treat nodes and node-proj collections uniformly.
23  * @author      Sebastian Hack
24  */
25 #include "config.h"
26
27 #include "irgraph_t.h"
28 #include "irmode_t.h"
29 #include "irnode_t.h"
30 #include "iredges.h"
31
32 #include "bechordal_t.h"
33 #include "besched.h"
34 #include "beinsn_t.h"
35 #include "beabi.h"
36 #include "raw_bitset.h"
37
38 be_insn_t *be_scan_insn(be_chordal_env_t *const env, ir_node *const irn)
39 {
40         struct obstack *const obst = &env->obst;
41         be_operand_t o;
42
43         be_insn_t *insn = OALLOCZ(obst, be_insn_t);
44
45         bool has_constraints = false;
46
47         const arch_register_class_t *cls = env->cls;
48         insn->irn = irn;
49         be_foreach_definition(irn, cls, p, req,
50                 /* found a def: create a new operand */
51                 if (arch_register_req_is(req, limited)) {
52                         o.regs          = req->limited;
53                         has_constraints = true;
54                 } else {
55                         o.regs           = env->allocatable_regs->data;
56                         has_constraints |= req->width > 1;
57                 }
58                 o.carrier = p;
59                 o.partner = NULL;
60                 obstack_grow(obst, &o, sizeof(o));
61                 insn->n_ops++;
62         );
63
64         insn->use_start = insn->n_ops;
65
66         /* now collect the uses for this node */
67         be_foreach_use(irn, cls, in_req, op, op_req,
68                 /* found a register use, create an operand */
69                 if (arch_register_req_is(in_req, limited)) {
70                         o.regs          = in_req->limited;
71                         has_constraints = true;
72                 } else {
73                         o.regs = env->allocatable_regs->data;
74                 }
75                 o.carrier = op;
76                 o.partner = NULL;
77                 obstack_grow(obst, &o, sizeof(o));
78                 insn->n_ops++;
79         );
80
81         if (!has_constraints)
82                 return NULL;
83
84         insn->ops = (be_operand_t*)obstack_finish(obst);
85         return insn;
86 }