Branch data Line data Source code
1 : : /* Function return value location for ARM EABI.
2 : : Copyright (C) 2009-2010, 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 arm_
37 : : #include "libebl_CPU.h"
38 : :
39 : :
40 : : /* r0, or pair r0, r1, or aggregate up to r0-r3. */
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 : : { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 },
46 : : { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 },
47 : : };
48 : : #define nloc_intreg 1
49 : : #define nloc_intregs(n) (2 * (n))
50 : :
51 : : /* The return value is a structure and is actually stored in stack space
52 : : passed in a hidden argument by the caller. But, the compiler
53 : : helpfully returns the address of that space in r0. */
54 : : static const Dwarf_Op loc_aggregate[] =
55 : : {
56 : : { .atom = DW_OP_breg0, .number = 0 }
57 : : };
58 : : #define nloc_aggregate 1
59 : :
60 : :
61 : : int
62 : 0 : arm_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
63 : : {
64 : : /* Start with the function's type, and get the DW_AT_type attribute,
65 : : which is the type of the return value. */
66 : 0 : Dwarf_Die die_mem, *typedie = &die_mem;
67 : 0 : int tag = dwarf_peeled_die_type (functypedie, typedie);
68 [ # # ]: 0 : if (tag <= 0)
69 : : return tag;
70 : :
71 : 0 : Dwarf_Word size;
72 [ # # # # : 0 : switch (tag)
# ]
73 : : {
74 : : case -1:
75 : : return -1;
76 : :
77 : 0 : case DW_TAG_subrange_type:
78 [ # # ]: 0 : if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
79 : : {
80 : 0 : Dwarf_Attribute attr_mem, *attr;
81 : 0 : attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
82 : 0 : typedie = dwarf_formref_die (attr, &die_mem);
83 [ # # ]: 0 : tag = DWARF_TAG_OR_RETURN (typedie);
84 : : }
85 : 0 : FALLTHROUGH;
86 : :
87 : : case DW_TAG_base_type:
88 : : case DW_TAG_enumeration_type:
89 : : CASE_POINTER:
90 : : {
91 : 0 : Dwarf_Attribute attr_mem;
92 [ # # ]: 0 : if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
93 : : &attr_mem), &size) != 0)
94 : : {
95 [ # # ]: 0 : if (dwarf_is_pointer (tag))
96 : 0 : size = 4;
97 : : else
98 : : return -1;
99 : : }
100 [ # # ]: 0 : if (size <= 16)
101 : : {
102 : 0 : intreg:
103 : 0 : *locp = loc_intreg;
104 [ # # ]: 0 : return size <= 4 ? nloc_intreg : nloc_intregs ((size + 3) / 4);
105 : : }
106 : :
107 : 0 : aggregate:
108 : 0 : *locp = loc_aggregate;
109 : 0 : return nloc_aggregate;
110 : : }
111 : :
112 : 0 : case DW_TAG_structure_type:
113 : : case DW_TAG_class_type:
114 : : case DW_TAG_union_type:
115 : : case DW_TAG_array_type:
116 [ # # ]: 0 : if (dwarf_aggregate_size (typedie, &size) == 0
117 [ # # # # ]: 0 : && size > 0 && size <= 4)
118 : 0 : goto intreg;
119 : 0 : goto aggregate;
120 : : }
121 : :
122 : : /* XXX We don't have a good way to return specific errors from ebl calls.
123 : : This value means we do not understand the type, but it is well-formed
124 : : DWARF and might be valid. */
125 : 0 : return -2;
126 : : }
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