1 /* Function return value location for Linux/PPC64 ABI. 2 Copyright (C) 2005-2010 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 /* vr2. */ 57 static const Dwarf_Op loc_vmxreg[] = 58 { 59 { .atom = DW_OP_regx, .number = 1124 + 2 } 60 }; 61 #define nloc_vmxreg 1 62 63 /* The return value is a structure and is actually stored in stack space 64 passed in a hidden argument by the caller. But, the compiler 65 helpfully returns the address of that space in r3. */ 66 static const Dwarf_Op loc_aggregate[] = 67 { 68 { .atom = DW_OP_breg3, .number = 0 } 69 }; 70 #define nloc_aggregate 1 71 72 int 73 ppc64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) 74 { 75 /* Start with the function's type, and get the DW_AT_type attribute, 76 which is the type of the return value. */ 77 78 Dwarf_Attribute attr_mem; 79 Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type, 80 &attr_mem); 81 if (attr == NULL) 82 /* The function has no return value, like a `void' function in C. */ 83 return 0; 84 85 Dwarf_Die die_mem; 86 Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem); 87 int tag = dwarf_tag (typedie); 88 89 /* Follow typedefs and qualifiers to get to the actual type. */ 90 while (tag == DW_TAG_typedef 91 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type 92 || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type) 93 { 94 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 95 typedie = dwarf_formref_die (attr, &die_mem); 96 tag = dwarf_tag (typedie); 97 } 98 99 Dwarf_Word size; 100 switch (tag) 101 { 102 case -1: 103 return -1; 104 105 case DW_TAG_subrange_type: 106 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) 107 { 108 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 109 typedie = dwarf_formref_die (attr, &die_mem); 110 tag = dwarf_tag (typedie); 111 } 112 /* Fall through. */ 113 114 case DW_TAG_base_type: 115 case DW_TAG_enumeration_type: 116 case DW_TAG_pointer_type: 117 case DW_TAG_ptr_to_member_type: 118 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, 119 &attr_mem), &size) != 0) 120 { 121 if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) 122 size = 8; 123 else 124 return -1; 125 } 126 if (tag == DW_TAG_base_type) 127 { 128 Dwarf_Word encoding; 129 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, 130 &attr_mem), 131 &encoding) != 0) 132 return -1; 133 134 if (encoding == DW_ATE_float || encoding == DW_ATE_complex_float) 135 { 136 *locp = loc_fpreg; 137 if (size <= 8) 138 return nloc_fpreg; 139 if (size <= 16) 140 return nloc_fp2regs; 141 if (size <= 32) 142 return nloc_fp4regs; 143 } 144 } 145 if (size <= 8) 146 { 147 intreg: 148 *locp = loc_intreg; 149 return nloc_intreg; 150 } 151 152 /* Else fall through. */ 153 case DW_TAG_structure_type: 154 case DW_TAG_class_type: 155 case DW_TAG_union_type: 156 aggregate: 157 *locp = loc_aggregate; 158 return nloc_aggregate; 159 160 case DW_TAG_array_type: 161 { 162 bool is_vector; 163 if (dwarf_formflag (dwarf_attr_integrate (typedie, DW_AT_GNU_vector, 164 &attr_mem), &is_vector) == 0 165 && is_vector) 166 { 167 *locp = loc_vmxreg; 168 return nloc_vmxreg; 169 } 170 } 171 /* Fall through. */ 172 173 case DW_TAG_string_type: 174 if (dwarf_aggregate_size (typedie, &size) == 0 && size <= 8) 175 { 176 if (tag == DW_TAG_array_type) 177 { 178 /* Check if it's a character array. */ 179 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 180 typedie = dwarf_formref_die (attr, &die_mem); 181 tag = dwarf_tag (typedie); 182 if (tag != DW_TAG_base_type) 183 goto aggregate; 184 if (dwarf_formudata (dwarf_attr_integrate (typedie, 185 DW_AT_byte_size, 186 &attr_mem), 187 &size) != 0) 188 return -1; 189 if (size != 1) 190 goto aggregate; 191 } 192 goto intreg; 193 } 194 goto aggregate; 195 } 196 197 /* 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. */ 200 return -2; 201 } 202
