1 /* Function return value location for Linux/PPC ABI.
2 Copyright (C) 2005, 2006, 2007, 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 /* This is the SVR4 ELF ABI convention, but AIX and Linux do not use it. */
41 #define SVR4_STRUCT_RETURN 0
44 /* r3, or pair r3, r4, or quad r3-r6. */
45 static const Dwarf_Op loc_intreg[] =
47 { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 },
48 { .atom = DW_OP_reg4 }, { .atom = DW_OP_piece, .number = 4 },
49 { .atom = DW_OP_reg5 }, { .atom = DW_OP_piece, .number = 4 },
50 { .atom = DW_OP_reg6 }, { .atom = DW_OP_piece, .number = 4 },
53 #define nloc_intregpair 4
54 #define nloc_intregquad 8
57 static const Dwarf_Op loc_fpreg[] =
59 { .atom = DW_OP_regx, .number = 33 }
64 static const Dwarf_Op loc_vmxreg[] =
66 { .atom = DW_OP_regx, .number = 1124 + 2 }
70 /* The return value is a structure and is actually stored in stack space
71 passed in a hidden argument by the caller. But, the compiler
72 helpfully returns the address of that space in r3. */
73 static const Dwarf_Op loc_aggregate[] =
75 { .atom = DW_OP_breg3, .number = 0 }
77 #define nloc_aggregate 1
80 /* XXX We should check the SHT_GNU_ATTRIBUTES bits here (or in ppc_init). */
82 ppc_altivec_abi (void)
88 ppc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
90 /* Start with the function's type, and get the DW_AT_type attribute,
91 which is the type of the return value. */
93 Dwarf_Attribute attr_mem;
94 Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type,
97 /* The function has no return value, like a `void' function in C. */
101 Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
102 int tag = dwarf_tag (typedie);
104 /* Follow typedefs and qualifiers to get to the actual type. */
105 while (tag == DW_TAG_typedef
106 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type
107 || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type)
109 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
110 typedie = dwarf_formref_die (attr, &die_mem);
111 tag = dwarf_tag (typedie);
120 case DW_TAG_subrange_type:
121 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
123 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
124 typedie = dwarf_formref_die (attr, &die_mem);
125 tag = dwarf_tag (typedie);
129 case DW_TAG_base_type:
130 case DW_TAG_enumeration_type:
131 case DW_TAG_pointer_type:
132 case DW_TAG_ptr_to_member_type:
133 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
134 &attr_mem), &size) != 0)
136 if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
143 if (tag == DW_TAG_base_type)
146 if (dwarf_formudata (dwarf_attr_integrate (typedie,
151 if (encoding == DW_ATE_float)
159 return size <= 4 ? nloc_intreg : nloc_intregpair;
163 *locp = loc_aggregate;
164 return nloc_aggregate;
166 case DW_TAG_array_type:
169 if (dwarf_formflag (dwarf_attr_integrate (typedie, DW_AT_GNU_vector,
170 &attr_mem), &is_vector) == 0
172 && dwarf_aggregate_size (typedie, &size) == 0)
176 if (ppc_altivec_abi ())
182 return nloc_intregquad;
187 case DW_TAG_structure_type:
188 case DW_TAG_class_type:
189 case DW_TAG_union_type:
190 if (SVR4_STRUCT_RETURN
191 && dwarf_aggregate_size (typedie, &size) == 0
192 && size > 0 && size <= 8)
197 /* XXX We don't have a good way to return specific errors from ebl calls.
198 This value means we do not understand the type, but it is well-formed
199 DWARF and might be valid. */