1 /* Function return value location for Linux/PPC64 ABI. 2 Copyright (C) 2005, 2006, 2007 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 5 Red Hat elfutils is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by the 7 Free Software Foundation; version 2 of the License. 8 9 Red Hat elfutils is distributed in the hope that it will be useful, but 10 WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 General Public License for more details. 13 14 You should have received a copy of the GNU General Public License along 15 with Red Hat elfutils; if not, write to the Free Software Foundation, 16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 17 18 Red Hat elfutils is an included package of the Open Invention Network. 19 An included package of the Open Invention Network is a package for which 20 Open Invention Network licensees cross-license their patents. No patent 21 license is granted, either expressly or impliedly, by designation as an 22 included package. Should you wish to participate in the Open Invention 23 Network licensing program, please visit www.openinventionnetwork.com 24 <http://www.openinventionnetwork.com>. */ 25 26 #ifdef HAVE_CONFIG_H 27 # include <config.h> 28 #endif 29 30 #include <assert.h> 31 #include <dwarf.h> 32 33 #define BACKEND ppc64_ 34 #include "libebl_CPU.h" 35 36 37 /* r3. */ 38 static const Dwarf_Op loc_intreg[] = 39 { 40 { .atom = DW_OP_reg3 } 41 }; 42 #define nloc_intreg 1 43 44 /* f1, or f1:f2, or f1:f4. */ 45 static const Dwarf_Op loc_fpreg[] = 46 { 47 { .atom = DW_OP_regx, .number = 33 }, { .atom = DW_OP_piece, .number = 8 }, 48 { .atom = DW_OP_regx, .number = 34 }, { .atom = DW_OP_piece, .number = 8 }, 49 { .atom = DW_OP_regx, .number = 35 }, { .atom = DW_OP_piece, .number = 8 }, 50 { .atom = DW_OP_regx, .number = 36 }, { .atom = DW_OP_piece, .number = 8 }, 51 }; 52 #define nloc_fpreg 1 53 #define nloc_fp2regs 4 54 #define nloc_fp4regs 8 55 56 /* The return value is a structure and is actually stored in stack space 57 passed in a hidden argument by the caller. But, the compiler 58 helpfully returns the address of that space in r3. */ 59 static const Dwarf_Op loc_aggregate[] = 60 { 61 { .atom = DW_OP_breg3, .number = 0 } 62 }; 63 #define nloc_aggregate 1 64 65 int 66 ppc64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) 67 { 68 /* Start with the function's type, and get the DW_AT_type attribute, 69 which is the type of the return value. */ 70 71 Dwarf_Attribute attr_mem; 72 Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type, 73 &attr_mem); 74 if (attr == NULL) 75 /* The function has no return value, like a `void' function in C. */ 76 return 0; 77 78 Dwarf_Die die_mem; 79 Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem); 80 int tag = dwarf_tag (typedie); 81 82 /* Follow typedefs and qualifiers to get to the actual type. */ 83 while (tag == DW_TAG_typedef 84 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type 85 || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type) 86 { 87 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 88 typedie = dwarf_formref_die (attr, &die_mem); 89 tag = dwarf_tag (typedie); 90 } 91 92 Dwarf_Word size; 93 switch (tag) 94 { 95 case -1: 96 return -1; 97 98 case DW_TAG_subrange_type: 99 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) 100 { 101 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 102 typedie = dwarf_formref_die (attr, &die_mem); 103 tag = dwarf_tag (typedie); 104 } 105 /* Fall through. */ 106 107 case DW_TAG_base_type: 108 case DW_TAG_enumeration_type: 109 case DW_TAG_pointer_type: 110 case DW_TAG_ptr_to_member_type: 111 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, 112 &attr_mem), &size) != 0) 113 { 114 if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) 115 size = 8; 116 else 117 return -1; 118 } 119 if (tag == DW_TAG_base_type) 120 { 121 Dwarf_Word encoding; 122 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, 123 &attr_mem), 124 &encoding) != 0) 125 return -1; 126 127 if (encoding == DW_ATE_float || encoding == DW_ATE_complex_float) 128 { 129 *locp = loc_fpreg; 130 if (size <= 8) 131 return nloc_fpreg; 132 if (size <= 16) 133 return nloc_fp2regs; 134 if (size <= 32) 135 return nloc_fp4regs; 136 } 137 } 138 if (size <= 8) 139 { 140 intreg: 141 *locp = loc_intreg; 142 return nloc_intreg; 143 } 144 145 /* Else fall through. */ 146 case DW_TAG_structure_type: 147 case DW_TAG_class_type: 148 case DW_TAG_union_type: 149 aggregate: 150 *locp = loc_aggregate; 151 return nloc_aggregate; 152 153 case DW_TAG_string_type: 154 case DW_TAG_array_type: 155 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, 156 &attr_mem), &size) == 0 157 && size <= 8) 158 { 159 if (tag == DW_TAG_array_type) 160 { 161 /* Check if it's a character array. */ 162 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 163 typedie = dwarf_formref_die (attr, &die_mem); 164 tag = dwarf_tag (typedie); 165 if (tag != DW_TAG_base_type) 166 goto aggregate; 167 if (dwarf_formudata (dwarf_attr_integrate (typedie, 168 DW_AT_byte_size, 169 &attr_mem), 170 &size) != 0) 171 return -1; 172 if (size != 1) 173 goto aggregate; 174 } 175 goto intreg; 176 } 177 goto aggregate; 178 } 179 180 /* XXX We don't have a good way to return specific errors from ebl calls. 181 This value means we do not understand the type, but it is well-formed 182 DWARF and might be valid. */ 183 return -2; 184 } 185
