1 /* Function return value location for Linux/SH ABI.
2 Copyright (C) 2010, 2014 Red Hat, Inc.
3 This file is part of elfutils.
4 Contributed by Matt Fleming <[email protected]>.
5
6 This file is free software; you can redistribute it and/or modify
7 it under the terms of either
8
9 * the GNU Lesser General Public License as published by the Free
10 Software Foundation; either version 3 of the License, or (at
11 your option) any later version
12
13 or
14
15 * the GNU General Public License as published by the Free
16 Software Foundation; either version 2 of the License, or (at
17 your option) any later version
18
19 or both in parallel, as here.
20
21 elfutils is distributed in the hope that it will be useful, but
22 WITHOUT ANY WARRANTY; without even the implied warranty of
23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 General Public License for more details.
25
26 You should have received copies of the GNU General Public License and
27 the GNU Lesser General Public License along with this program. If
28 not, see <http://www.gnu.org/licenses/>. */
29
30 #ifdef HAVE_CONFIG_H
31 # include <config.h>
32 #endif
33
34 #include <assert.h>
35 #include <dwarf.h>
36
37 #define BACKEND sh_
38 #include "libebl_CPU.h"
39
40
41 /* This is the SVR4 ELF ABI convention, but AIX and Linux do not use it. */
42 #define SVR4_STRUCT_RETURN 0
43
44
45 /* r0, or pair r0, r1. */
46 static const Dwarf_Op loc_intreg[] =
47 {
48 { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 },
49 { .atom = DW_OP_reg1 }, { .atom = DW_OP_piece, .number = 4 },
50 };
51 #define nloc_intreg 1
52 #define nloc_intregpair 4
53
54 /* fr0 or fr1. */
55 static const Dwarf_Op loc_fpreg[] =
56 {
57 { .atom = DW_OP_reg25 }, { .atom = DW_OP_piece, .number = 4 },
58 { .atom = DW_OP_reg26 }, { .atom = DW_OP_piece, .number = 4 },
59 };
60 #define nloc_fpreg 1
61 #define nloc_fpregpair 2
62
63 int
sh_return_value_location(Dwarf_Die * functypedie,const Dwarf_Op ** locp)64 sh_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
65 {
66 /* Start with the function's type, and get the DW_AT_type attribute,
67 which is the type of the return value. */
68 Dwarf_Die die_mem, *typedie = &die_mem;
69 int tag = dwarf_peeled_die_type (functypedie, typedie);
70 if (tag <= 0)
71 return tag;
72
73 Dwarf_Word size;
74 switch (tag)
75 {
76 case -1:
77 return -1;
78
79 case DW_TAG_subrange_type:
80 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
81 {
82 Dwarf_Attribute attr_mem, *attr;
83 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
84 typedie = dwarf_formref_die (attr, &die_mem);
85 tag = DWARF_TAG_OR_RETURN (typedie);
86 }
87 FALLTHROUGH;
88
89 case DW_TAG_base_type:
90 case DW_TAG_enumeration_type:
91 CASE_POINTER:
92 {
93 Dwarf_Attribute attr_mem;
94 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
95 &attr_mem), &size) != 0)
96 {
97 if (dwarf_is_pointer (tag))
98 size = 4;
99 else
100 return -1;
101 }
102 }
103
104 if (size <= 8)
105 {
106 if (tag == DW_TAG_base_type)
107 {
108 Dwarf_Attribute attr_mem;
109 Dwarf_Word encoding;
110 if (dwarf_formudata (dwarf_attr_integrate (typedie,
111 DW_AT_encoding,
112 &attr_mem),
113 &encoding) != 0)
114 return -1;
115 if (encoding == DW_ATE_float)
116 {
117 *locp = loc_fpreg;
118 return size <= 4 ? nloc_fpreg : nloc_fpregpair;
119 }
120 }
121 *locp = loc_intreg;
122 return size <= 4 ? nloc_intreg : nloc_intregpair;
123 }
124 }
125
126 /* XXX We don't have a good way to return specific errors from ebl calls.
127 This value means we do not understand the type, but it is well-formed
128 DWARF and might be valid. */
129 return -2;
130 }
131