1 /* Function return value location for Linux/TILE-Gx ABI.
2 Copyright (C) 2012 Tilera Corporation
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 #define BACKEND tilegx_
38 #include "libebl_CPU.h"
42 static const Dwarf_Op loc_intreg[] =
44 { .atom = DW_OP_reg0 }
48 /* The return value is a structure and is actually stored in stack space
49 passed in a hidden argument by the caller. But, the compiler
50 helpfully returns the address of that space in r0. */
51 static const Dwarf_Op loc_aggregate[] =
53 { .atom = DW_OP_breg0, .number = 0 }
55 #define nloc_aggregate 1
58 tilegx_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
60 /* Start with the function's type, and get the DW_AT_type attribute,
61 which is the type of the return value. */
63 Dwarf_Attribute attr_mem;
64 Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type,
67 /* The function has no return value, like a `void' function in C. */
71 Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
72 int tag = dwarf_tag (typedie);
74 /* Follow typedefs and qualifiers to get to the actual type. */
75 while (tag == DW_TAG_typedef
76 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type
77 || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type)
79 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
80 typedie = dwarf_formref_die (attr, &die_mem);
81 tag = dwarf_tag (typedie);
90 case DW_TAG_subrange_type:
91 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
93 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
94 typedie = dwarf_formref_die (attr, &die_mem);
95 tag = dwarf_tag (typedie);
99 case DW_TAG_base_type:
100 case DW_TAG_enumeration_type:
101 case DW_TAG_pointer_type:
102 case DW_TAG_ptr_to_member_type:
103 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
104 &attr_mem), &size) != 0)
106 if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
111 if (tag == DW_TAG_base_type)
114 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding,
120 /* Small enough structs are passed directly in registers R0 ... R7. */
128 /* Else fall through. */
129 case DW_TAG_structure_type:
130 case DW_TAG_class_type:
131 case DW_TAG_union_type:
133 *locp = loc_aggregate;
134 return nloc_aggregate;
136 case DW_TAG_array_type:
137 case DW_TAG_string_type:
138 if (dwarf_aggregate_size (typedie, &size) == 0 && size <= 8)
140 if (tag == DW_TAG_array_type)
142 /* Check if it's a character array. */
143 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
144 typedie = dwarf_formref_die (attr, &die_mem);
145 tag = dwarf_tag (typedie);
146 if (tag != DW_TAG_base_type)
148 if (dwarf_formudata (dwarf_attr_integrate (typedie,
161 /* XXX We don't have a good way to return specific errors from ebl calls.
162 This value means we do not understand the type, but it is well-formed
163 DWARF and might be valid. */