1 /* Function return value location for Linux/SH ABI. 2 Copyright (C) 2010, 2014 Red Hat, Inc. 3 This file is part of elfutils. 4 Contributed by Matt Fleming <matt (at) console-pimps.org>. 5 6 This file is free software; you can redistribute it and/or modify 7 it under the terms of either 8 9 * the GNU Lesser General Public License as published by the Free 10 Software Foundation; either version 3 of the License, or (at 11 your option) any later version 12 13 or 14 15 * the GNU General Public License as published by the Free 16 Software Foundation; either version 2 of the License, or (at 17 your option) any later version 18 19 or both in parallel, as here. 20 21 elfutils is distributed in the hope that it will be useful, but 22 WITHOUT ANY WARRANTY; without even the implied warranty of 23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 24 General Public License for more details. 25 26 You should have received copies of the GNU General Public License and 27 the GNU Lesser General Public License along with this program. If 28 not, see <http://www.gnu.org/licenses/>. */ 29 30 #ifdef HAVE_CONFIG_H 31 # include <config.h> 32 #endif 33 34 #include <assert.h> 35 #include <dwarf.h> 36 37 #define BACKEND sh_ 38 #include "libebl_CPU.h" 39 40 41 /* This is the SVR4 ELF ABI convention, but AIX and Linux do not use it. */ 42 #define SVR4_STRUCT_RETURN 0 43 44 45 /* r0, or pair r0, r1. */ 46 static const Dwarf_Op loc_intreg[] = 47 { 48 { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 }, 49 { .atom = DW_OP_reg1 }, { .atom = DW_OP_piece, .number = 4 }, 50 }; 51 #define nloc_intreg 1 52 #define nloc_intregpair 4 53 54 /* fr0 or fr1. */ 55 static const Dwarf_Op loc_fpreg[] = 56 { 57 { .atom = DW_OP_reg25 }, { .atom = DW_OP_piece, .number = 4 }, 58 { .atom = DW_OP_reg26 }, { .atom = DW_OP_piece, .number = 4 }, 59 }; 60 #define nloc_fpreg 1 61 #define nloc_fpregpair 2 62 63 int 64 sh_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) 65 { 66 /* Start with the function's type, and get the DW_AT_type attribute, 67 which is the type of the return value. */ 68 Dwarf_Die die_mem, *typedie = &die_mem; 69 int tag = dwarf_peeled_die_type (functypedie, typedie); 70 if (tag <= 0) 71 return tag; 72 73 Dwarf_Word size; 74 switch (tag) 75 { 76 case -1: 77 return -1; 78 79 case DW_TAG_subrange_type: 80 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) 81 { 82 Dwarf_Attribute attr_mem, *attr; 83 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 84 typedie = dwarf_formref_die (attr, &die_mem); 85 tag = DWARF_TAG_OR_RETURN (typedie); 86 } 87 /* Fall through. */ 88 89 case DW_TAG_base_type: 90 case DW_TAG_enumeration_type: 91 case DW_TAG_pointer_type: 92 case DW_TAG_ptr_to_member_type: 93 { 94 Dwarf_Attribute attr_mem; 95 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, 96 &attr_mem), &size) != 0) 97 { 98 if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) 99 size = 4; 100 else 101 return -1; 102 } 103 } 104 105 if (size <= 8) 106 { 107 if (tag == DW_TAG_base_type) 108 { 109 Dwarf_Attribute attr_mem; 110 Dwarf_Word encoding; 111 if (dwarf_formudata (dwarf_attr_integrate (typedie, 112 DW_AT_encoding, 113 &attr_mem), 114 &encoding) != 0) 115 return -1; 116 if (encoding == DW_ATE_float) 117 { 118 *locp = loc_fpreg; 119 return size <= 4 ? nloc_fpreg : nloc_fpregpair; 120 } 121 } 122 *locp = loc_intreg; 123 return size <= 4 ? nloc_intreg : nloc_intregpair; 124 } 125 } 126 127 /* XXX We don't have a good way to return specific errors from ebl calls. 128 This value means we do not understand the type, but it is well-formed 129 DWARF and might be valid. */ 130 return -2; 131 } 132
