1 /* Function return value location for SPARC.
2 Copyright (C) 2006-2010, 2014 Red Hat, Inc.
3 This file is part of elfutils.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
7
8 * the GNU Lesser General Public License as published by the Free
9 Software Foundation; either version 3 of the License, or (at
10 your option) any later version
11
12 or
13
14 * the GNU General Public License as published by the Free
15 Software Foundation; either version 2 of the License, or (at
16 your option) any later version
17
18 or both in parallel, as here.
19
20 elfutils is distributed in the hope that it will be useful, but
21 WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 General Public License for more details.
24
25 You should have received copies of the GNU General Public License and
26 the GNU Lesser General Public License along with this program. If
27 not, see <http://www.gnu.org/licenses/>. */
28
29 #ifdef HAVE_CONFIG_H
30 # include <config.h>
31 #endif
32
33 #include <assert.h>
34 #include <dwarf.h>
35
36 #define BACKEND sparc_
37 #include "libebl_CPU.h"
38
39
40 /* %o0, or pair %o0, %o1. */
41 static const Dwarf_Op loc_intreg[] =
42 {
43 { .atom = DW_OP_reg8 }, { .atom = DW_OP_piece, .number = 4 },
44 { .atom = DW_OP_reg9 }, { .atom = DW_OP_piece, .number = 4 },
45 };
46 #define nloc_intreg 1
47 #define nloc_intregpair 4
48
49 /* %f0 or pair %f0, %f1, or quad %f0..%f3. */
50 static const Dwarf_Op loc_fpreg[] =
51 {
52 { .atom = DW_OP_regx, .number = 32 }, { .atom = DW_OP_piece, .number = 4 },
53 { .atom = DW_OP_regx, .number = 33 }, { .atom = DW_OP_piece, .number = 4 },
54 { .atom = DW_OP_regx, .number = 34 }, { .atom = DW_OP_piece, .number = 4 },
55 { .atom = DW_OP_regx, .number = 35 }, { .atom = DW_OP_piece, .number = 4 },
56 };
57 #define nloc_fpreg 1
58 #define nloc_fpregpair 4
59 #define nloc_fpregquad 8
60
61 /* The return value is a structure and is actually stored in stack space
62 passed in a hidden argument by the caller. But, the compiler
63 helpfully returns the address of that space in %o0. */
64 static const Dwarf_Op loc_aggregate[] =
65 {
66 { .atom = DW_OP_breg8, .number = 0 }
67 };
68 #define nloc_aggregate 1
69
70 int
sparc_return_value_location(Dwarf_Die * functypedie,const Dwarf_Op ** locp)71 sparc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
72 {
73 /* Start with the function's type, and get the DW_AT_type attribute,
74 which is the type of the return value. */
75 Dwarf_Die die_mem, *typedie = &die_mem;
76 int tag = dwarf_peeled_die_type (functypedie, typedie);
77 if (tag <= 0)
78 return tag;
79
80 Dwarf_Word size;
81 switch (tag)
82 {
83 case -1:
84 return -1;
85
86 case DW_TAG_subrange_type:
87 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
88 {
89 Dwarf_Attribute attr_mem, *attr;
90 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
91 typedie = dwarf_formref_die (attr, &die_mem);
92 tag = DWARF_TAG_OR_RETURN (typedie);
93 }
94 FALLTHROUGH;
95
96 case DW_TAG_base_type:
97 case DW_TAG_enumeration_type:
98 CASE_POINTER:
99 {
100 Dwarf_Attribute attr_mem;
101 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
102 &attr_mem), &size) != 0)
103 {
104 uint8_t asize;
105 Dwarf_Die cudie;
106 if (dwarf_is_pointer (tag)
107 && dwarf_diecu (typedie, &cudie, &asize, NULL) != NULL)
108 size = asize;
109 else
110 return -1;
111 }
112 }
113
114 if (tag == DW_TAG_base_type)
115 {
116 Dwarf_Attribute attr_mem;
117 Dwarf_Word encoding;
118 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding,
119 &attr_mem),
120 &encoding) != 0)
121 return -1;
122 if (encoding == DW_ATE_float)
123 {
124 *locp = loc_fpreg;
125 if (size <= 4)
126 return nloc_fpreg;
127 if (size <= 8)
128 return nloc_fpregpair;
129 if (size <= 16)
130 return nloc_fpregquad;
131 }
132 }
133 if (size <= 8)
134 {
135 intreg:
136 *locp = loc_intreg;
137 return size <= 4 ? nloc_intreg : nloc_intregpair;
138 }
139
140 aggregate:
141 *locp = loc_aggregate;
142 return nloc_aggregate;
143
144 case DW_TAG_structure_type:
145 case DW_TAG_class_type:
146 case DW_TAG_union_type:
147 case DW_TAG_array_type:
148 if (dwarf_aggregate_size (typedie, &size) == 0
149 && size > 0 && size <= 8)
150 goto intreg;
151 goto aggregate;
152 }
153
154 /* XXX We don't have a good way to return specific errors from ebl calls.
155 This value means we do not understand the type, but it is well-formed
156 DWARF and might be valid. */
157 return -2;
158 }
159