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1 : : /* Function return value location for Linux/m68k ABI.
2 : : This file is part of elfutils.
3 : :
4 : : This file is free software; you can redistribute it and/or modify
5 : : it under the terms of either
6 : :
7 : : * the GNU Lesser General Public License as published by the Free
8 : : Software Foundation; either version 3 of the License, or (at
9 : : your option) any later version
10 : :
11 : : or
12 : :
13 : : * the GNU General Public License as published by the Free
14 : : Software Foundation; either version 2 of the License, or (at
15 : : your option) any later version
16 : :
17 : : or both in parallel, as here.
18 : :
19 : : elfutils is distributed in the hope that it will be useful, but
20 : : WITHOUT ANY WARRANTY; without even the implied warranty of
21 : : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 : : General Public License for more details.
23 : :
24 : : You should have received copies of the GNU General Public License and
25 : : the GNU Lesser General Public License along with this program. If
26 : : not, see <http://www.gnu.org/licenses/>. */
27 : :
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 m68k_
37 : : #include "libebl_CPU.h"
38 : :
39 : :
40 : : /* %d0, or pair %d0, %d1. */
41 : : static const Dwarf_Op loc_intreg[] =
42 : : {
43 : : { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 },
44 : : { .atom = DW_OP_reg1 }, { .atom = DW_OP_piece, .number = 4 },
45 : : };
46 : : #define nloc_intreg 1
47 : : #define nloc_intregpair 4
48 : :
49 : : /* %a0. */
50 : : static const Dwarf_Op loc_ptrreg[] =
51 : : {
52 : : { .atom = DW_OP_reg8 }
53 : : };
54 : : #define nloc_ptrreg 1
55 : :
56 : : /* %fp0. */
57 : : static const Dwarf_Op loc_fpreg[] =
58 : : {
59 : : { .atom = DW_OP_reg16 }
60 : : };
61 : : #define nloc_fpreg 1
62 : :
63 : : /* The return value is a structure and is actually stored in stack space
64 : : passed in a hidden argument by the caller. But, the compiler
65 : : helpfully returns the address of that space in %a0. */
66 : : static const Dwarf_Op loc_aggregate[] =
67 : : {
68 : : { .atom = DW_OP_reg8 }
69 : : };
70 : : #define nloc_aggregate 1
71 : :
72 : : int
73 : 0 : m68k_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
74 : : {
75 : : /* Start with the function's type, and get the DW_AT_type attribute,
76 : : which is the type of the return value. */
77 : 0 : Dwarf_Die die_mem, *typedie = &die_mem;
78 : 0 : int tag = dwarf_peeled_die_type (functypedie, typedie);
79 [ # # ]: 0 : if (tag <= 0)
80 : : return tag;
81 : :
82 [ # # # # : 0 : switch (tag)
# ]
83 : : {
84 : : case -1:
85 : : return -1;
86 : :
87 : 0 : case DW_TAG_subrange_type:
88 [ # # ]: 0 : if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
89 : : {
90 : 0 : Dwarf_Attribute attr_mem, *attr;
91 : 0 : attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
92 : 0 : typedie = dwarf_formref_die (attr, &die_mem);
93 [ # # ]: 0 : tag = DWARF_TAG_OR_RETURN (typedie);
94 : : }
95 : 0 : FALLTHROUGH;
96 : :
97 : : case DW_TAG_base_type:
98 : : case DW_TAG_enumeration_type:
99 : : CASE_POINTER:
100 : : {
101 : 0 : Dwarf_Word size;
102 : 0 : Dwarf_Attribute attr_mem;
103 [ # # ]: 0 : if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
104 : : &attr_mem), &size) != 0)
105 : : {
106 [ # # ]: 0 : if (dwarf_is_pointer (tag))
107 : 0 : size = 4;
108 : : else
109 : 0 : return -1;
110 : : }
111 [ # # ]: 0 : if (tag == DW_TAG_base_type)
112 : : {
113 : 0 : Dwarf_Word encoding;
114 [ # # ]: 0 : if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding,
115 : : &attr_mem),
116 : : &encoding) != 0)
117 : 0 : return -1;
118 [ # # ]: 0 : if (encoding == DW_ATE_float)
119 : : {
120 [ # # ]: 0 : if (size > 12)
121 : : return -2;
122 : 0 : *locp = loc_fpreg;
123 : 0 : return nloc_fpreg;
124 : : }
125 : : }
126 [ # # ]: 0 : if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
127 : : {
128 : 0 : *locp = loc_ptrreg;
129 : 0 : return nloc_ptrreg;
130 : : }
131 : 0 : *locp = loc_intreg;
132 [ # # ]: 0 : if (size <= 4)
133 : : return nloc_intreg;
134 [ # # ]: 0 : if (size <= 8)
135 : : return nloc_intregpair;
136 : : }
137 : 0 : FALLTHROUGH;
138 : : case DW_TAG_structure_type:
139 : : case DW_TAG_class_type:
140 : : case DW_TAG_union_type:
141 : : case DW_TAG_array_type:
142 : 0 : *locp = loc_aggregate;
143 : 0 : return nloc_aggregate;
144 : : }
145 : :
146 : : /* XXX We don't have a good way to return specific errors from ebl calls.
147 : : This value means we do not understand the type, but it is well-formed
148 : : DWARF and might be valid. */
149 : 0 : return -2;
150 : : }
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