Line data Source code
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 DW_TAG_pointer_type:
100 : case DW_TAG_ptr_to_member_type:
101 0 : {
102 0 : Dwarf_Word size;
103 0 : Dwarf_Attribute attr_mem;
104 0 : if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
105 : &attr_mem), &size) != 0)
106 : {
107 0 : if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
108 0 : size = 4;
109 : else
110 0 : return -1;
111 : }
112 0 : if (tag == DW_TAG_base_type)
113 : {
114 0 : Dwarf_Word encoding;
115 0 : if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding,
116 : &attr_mem),
117 : &encoding) != 0)
118 0 : return -1;
119 0 : if (encoding == DW_ATE_float)
120 : {
121 0 : if (size > 12)
122 : return -2;
123 0 : *locp = loc_fpreg;
124 0 : return nloc_fpreg;
125 : }
126 : }
127 0 : if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
128 : {
129 0 : *locp = loc_ptrreg;
130 0 : return nloc_ptrreg;
131 : }
132 0 : *locp = loc_intreg;
133 0 : if (size <= 4)
134 : return nloc_intreg;
135 0 : if (size <= 8)
136 : return nloc_intregpair;
137 : }
138 0 : FALLTHROUGH;
139 : case DW_TAG_structure_type:
140 : case DW_TAG_class_type:
141 : case DW_TAG_union_type:
142 : case DW_TAG_array_type:
143 0 : *locp = loc_aggregate;
144 0 : return nloc_aggregate;
145 : }
146 :
147 : /* XXX We don't have a good way to return specific errors from ebl calls.
148 : This value means we do not understand the type, but it is well-formed
149 : DWARF and might be valid. */
150 0 : return -2;
151 : }
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