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 DW_TAG_pointer_type:
99 case DW_TAG_ptr_to_member_type:
100 {
101 Dwarf_Attribute attr_mem;
102 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
103 &attr_mem), &size) != 0)
104 {
105 uint8_t asize;
106 Dwarf_Die cudie;
107 if ((tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
108 && dwarf_diecu (typedie, &cudie, &asize, NULL) != NULL)
109 size = asize;
110 else
111 return -1;
112 }
113 }
114
115 if (tag == DW_TAG_base_type)
116 {
117 Dwarf_Attribute attr_mem;
118 Dwarf_Word encoding;
119 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding,
120 &attr_mem),
121 &encoding) != 0)
122 return -1;
123 if (encoding == DW_ATE_float)
124 {
125 *locp = loc_fpreg;
126 if (size <= 4)
127 return nloc_fpreg;
128 if (size <= 8)
129 return nloc_fpregpair;
130 if (size <= 16)
131 return nloc_fpregquad;
132 }
133 }
134 if (size <= 8)
135 {
136 intreg:
137 *locp = loc_intreg;
138 return size <= 4 ? nloc_intreg : nloc_intregpair;
139 }
140
141 aggregate:
142 *locp = loc_aggregate;
143 return nloc_aggregate;
144
145 case DW_TAG_structure_type:
146 case DW_TAG_class_type:
147 case DW_TAG_union_type:
148 case DW_TAG_array_type:
149 if (dwarf_aggregate_size (typedie, &size) == 0
150 && size > 0 && size <= 8)
151 goto intreg;
152 goto aggregate;
153 }
154
155 /* XXX We don't have a good way to return specific errors from ebl calls.
156 This value means we do not understand the type, but it is well-formed
157 DWARF and might be valid. */
158 return -2;
159 }
160