Line data Source code
1 : /* Function return value location for Alpha ELF ABI.
2 : Copyright (C) 2005, 2007, 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 alpha_
37 : #include "libebl_CPU.h"
38 :
39 :
40 : /* $0. */
41 : static const Dwarf_Op loc_intreg[] =
42 : {
43 : { .atom = DW_OP_reg0 }
44 : };
45 : #define nloc_intreg 1
46 :
47 : /* $f0, or pair $f0, $f1. */
48 : static const Dwarf_Op loc_fpreg[] =
49 : {
50 : { .atom = DW_OP_regx, .number = 32 }, { .atom = DW_OP_piece, .number = 4 },
51 : { .atom = DW_OP_regx, .number = 33 }, { .atom = DW_OP_piece, .number = 4 },
52 : };
53 : #define nloc_fpreg 1
54 : #define nloc_fpregpair 4
55 :
56 : /* The return value is a structure and is actually stored in stack space
57 : passed in a hidden argument by the caller. But, the compiler
58 : helpfully returns the address of that space in $0. */
59 : static const Dwarf_Op loc_aggregate[] =
60 : {
61 : { .atom = DW_OP_breg0, .number = 0 }
62 : };
63 : #define nloc_aggregate 1
64 :
65 : int
66 0 : alpha_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
67 : {
68 : /* Start with the function's type, and get the DW_AT_type attribute,
69 : which is the type of the return value. */
70 0 : Dwarf_Die die_mem, *typedie = &die_mem;
71 0 : int tag = dwarf_peeled_die_type (functypedie, typedie);
72 0 : if (tag <= 0)
73 : return tag;
74 :
75 0 : switch (tag)
76 : {
77 : case -1:
78 : return -1;
79 :
80 0 : case DW_TAG_subrange_type:
81 0 : if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
82 : {
83 0 : Dwarf_Attribute attr_mem, *attr;
84 0 : attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
85 0 : typedie = dwarf_formref_die (attr, &die_mem);
86 0 : tag = DWARF_TAG_OR_RETURN (typedie);
87 : }
88 0 : FALLTHROUGH;
89 :
90 : case DW_TAG_base_type:
91 : case DW_TAG_enumeration_type:
92 : case DW_TAG_pointer_type:
93 : case DW_TAG_ptr_to_member_type:
94 0 : {
95 0 : Dwarf_Attribute attr_mem;
96 0 : Dwarf_Word size;
97 0 : if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
98 : &attr_mem), &size) != 0)
99 : {
100 0 : if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
101 0 : size = 8;
102 : else
103 0 : return -1;
104 : }
105 0 : if (tag == DW_TAG_base_type)
106 : {
107 0 : Dwarf_Word encoding;
108 0 : if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding,
109 : &attr_mem),
110 : &encoding) != 0)
111 0 : return -1;
112 :
113 0 : *locp = loc_fpreg;
114 0 : if (encoding == DW_ATE_float)
115 : {
116 0 : if (size <= 8)
117 : return nloc_fpreg;
118 0 : goto aggregate;
119 : }
120 0 : if (encoding == DW_ATE_complex_float)
121 : {
122 0 : if (size <= 8 * 2)
123 : return nloc_fpregpair;
124 : goto aggregate;
125 : }
126 : }
127 0 : if (size <= 8)
128 : {
129 0 : *locp = loc_intreg;
130 0 : return nloc_intreg;
131 : }
132 : }
133 :
134 0 : FALLTHROUGH;
135 :
136 : case DW_TAG_structure_type:
137 : case DW_TAG_class_type:
138 : case DW_TAG_union_type:
139 : case DW_TAG_string_type:
140 : case DW_TAG_array_type:
141 0 : aggregate:
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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