1 /* Function return value location for ARM EABI.
2 Copyright (C) 2009-2010 Red Hat, Inc.
3 This file is part of elfutils.
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
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
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
18 or both in parallel, as here.
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.
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/>. */
37 #include "libebl_CPU.h"
40 /* r0, or pair r0, r1, or aggregate up to r0-r3. */
41 static const Dwarf_Op loc_intreg[] =
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 },
49 #define nloc_intregs(n) (2 * (n))
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[] =
56 { .atom = DW_OP_breg0, .number = 0 }
58 #define nloc_aggregate 1
62 arm_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
64 /* Start with the function's type, and get the DW_AT_type attribute,
65 which is the type of the return value. */
67 Dwarf_Attribute attr_mem;
68 Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type,
71 /* The function has no return value, like a `void' function in C. */
75 Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
76 int tag = dwarf_tag (typedie);
78 /* Follow typedefs and qualifiers to get to the actual type. */
79 while (tag == DW_TAG_typedef
80 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type
81 || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type)
83 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
84 typedie = dwarf_formref_die (attr, &die_mem);
85 tag = dwarf_tag (typedie);
94 case DW_TAG_subrange_type:
95 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
97 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
98 typedie = dwarf_formref_die (attr, &die_mem);
99 tag = dwarf_tag (typedie);
103 case DW_TAG_base_type:
104 case DW_TAG_enumeration_type:
105 case DW_TAG_pointer_type:
106 case DW_TAG_ptr_to_member_type:
107 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
108 &attr_mem), &size) != 0)
110 if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
119 return size <= 4 ? nloc_intreg : nloc_intregs ((size + 3) / 4);
123 *locp = loc_aggregate;
124 return nloc_aggregate;
126 case DW_TAG_structure_type:
127 case DW_TAG_class_type:
128 case DW_TAG_union_type:
129 case DW_TAG_array_type:
130 if (dwarf_aggregate_size (typedie, &size) == 0
131 && size > 0 && size <= 4)
136 /* XXX We don't have a good way to return specific errors from ebl calls.
137 This value means we do not understand the type, but it is well-formed
138 DWARF and might be valid. */