Line data Source code
1 : /* Function return value location for S/390 ABI.
2 : Copyright (C) 2006, 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 s390_
37 : #include "libebl_CPU.h"
38 :
39 :
40 : /* %r2, or pair %r2, %r3. */
41 : static const Dwarf_Op loc_intreg[] =
42 : {
43 : { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 },
44 : { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 },
45 : };
46 : #define nloc_intreg 1
47 : #define nloc_intregpair 4
48 :
49 : /* %f0. */
50 : static const Dwarf_Op loc_fpreg[] =
51 : {
52 : { .atom = DW_OP_reg16 },
53 : };
54 : #define nloc_fpreg 1
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 %r2. */
59 : static const Dwarf_Op loc_aggregate[] =
60 : {
61 : { .atom = DW_OP_breg2, .number = 0 }
62 : };
63 : #define nloc_aggregate 1
64 :
65 :
66 : int
67 0 : s390_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
68 : {
69 : /* Start with the function's type, and get the DW_AT_type attribute,
70 : which is the type of the return value. */
71 0 : Dwarf_Die die_mem, *typedie = &die_mem;
72 0 : int tag = dwarf_peeled_die_type (functypedie, typedie);
73 0 : if (tag <= 0)
74 : return tag;
75 :
76 0 : Dwarf_Word size;
77 0 : switch (tag)
78 : {
79 : case -1:
80 : return -1;
81 :
82 0 : case DW_TAG_subrange_type:
83 0 : if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
84 : {
85 0 : Dwarf_Attribute attr_mem, *attr;
86 0 : attr = dwarf_attr (typedie, DW_AT_type, &attr_mem);
87 0 : typedie = dwarf_formref_die (attr, &die_mem);
88 0 : tag = DWARF_TAG_OR_RETURN (typedie);
89 : }
90 0 : FALLTHROUGH;
91 :
92 : case DW_TAG_base_type:
93 : case DW_TAG_enumeration_type:
94 : case DW_TAG_pointer_type:
95 : case DW_TAG_ptr_to_member_type:
96 0 : {
97 0 : Dwarf_Die cudie;
98 0 : uint8_t asize;
99 0 : if (dwarf_diecu (typedie, &cudie, &asize, NULL) == NULL)
100 0 : return -1;
101 :
102 0 : Dwarf_Attribute attr_mem;
103 0 : if (dwarf_formudata (dwarf_attr (typedie, DW_AT_byte_size,
104 : &attr_mem), &size) != 0)
105 : {
106 0 : if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
107 0 : size = asize;
108 : else
109 : 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 && size <= 8)
119 : {
120 0 : *locp = loc_fpreg;
121 0 : return nloc_fpreg;
122 : }
123 : }
124 0 : if (size <= 8)
125 : {
126 0 : *locp = loc_intreg;
127 0 : return size <= asize ? nloc_intreg : nloc_intregpair;
128 : }
129 : }
130 0 : FALLTHROUGH;
131 :
132 : case DW_TAG_structure_type:
133 : case DW_TAG_class_type:
134 : case DW_TAG_union_type:
135 : case DW_TAG_array_type:
136 0 : *locp = loc_aggregate;
137 0 : return nloc_aggregate;
138 : }
139 :
140 : /* XXX We don't have a good way to return specific errors from ebl calls.
141 : This value means we do not understand the type, but it is well-formed
142 : DWARF and might be valid. */
143 0 : return -2;
144 : }
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