Ben Cheng | cc6695e | 2012-03-07 23:04:02 -0800 | [diff] [blame] | 1 | /* Function return value location for IA64 ABI. |
| 2 | Copyright (C) 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 ia64_ |
| 34 | #include "libebl_CPU.h" |
| 35 | |
| 36 | |
| 37 | /* r8, or pair r8, r9, or aggregate up to r8-r11. */ |
| 38 | static const Dwarf_Op loc_intreg[] = |
| 39 | { |
| 40 | { .atom = DW_OP_reg8 }, { .atom = DW_OP_piece, .number = 8 }, |
| 41 | { .atom = DW_OP_reg9 }, { .atom = DW_OP_piece, .number = 8 }, |
| 42 | { .atom = DW_OP_reg10 }, { .atom = DW_OP_piece, .number = 8 }, |
| 43 | { .atom = DW_OP_reg11 }, { .atom = DW_OP_piece, .number = 8 }, |
| 44 | }; |
| 45 | #define nloc_intreg 1 |
| 46 | #define nloc_intregs(n) (2 * (n)) |
| 47 | |
| 48 | /* f8, or aggregate up to f8-f15. */ |
| 49 | #define DEFINE_FPREG(size) \ |
| 50 | static const Dwarf_Op loc_fpreg_##size[] = \ |
| 51 | { \ |
| 52 | { .atom = DW_OP_regx, .number = 128 + 8 }, \ |
| 53 | { .atom = DW_OP_piece, .number = size }, \ |
| 54 | { .atom = DW_OP_regx, .number = 128 + 9 }, \ |
| 55 | { .atom = DW_OP_piece, .number = size }, \ |
| 56 | { .atom = DW_OP_regx, .number = 128 + 10 }, \ |
| 57 | { .atom = DW_OP_piece, .number = size }, \ |
| 58 | { .atom = DW_OP_regx, .number = 128 + 11 }, \ |
| 59 | { .atom = DW_OP_piece, .number = size }, \ |
| 60 | { .atom = DW_OP_regx, .number = 128 + 12 }, \ |
| 61 | { .atom = DW_OP_piece, .number = size }, \ |
| 62 | { .atom = DW_OP_regx, .number = 128 + 13 }, \ |
| 63 | { .atom = DW_OP_piece, .number = size }, \ |
| 64 | { .atom = DW_OP_regx, .number = 128 + 14 }, \ |
| 65 | { .atom = DW_OP_piece, .number = size }, \ |
| 66 | { .atom = DW_OP_regx, .number = 128 + 15 }, \ |
| 67 | { .atom = DW_OP_piece, .number = size }, \ |
| 68 | } |
| 69 | #define nloc_fpreg 1 |
| 70 | #define nloc_fpregs(n) (2 * (n)) |
| 71 | |
| 72 | DEFINE_FPREG (4); |
| 73 | DEFINE_FPREG (8); |
| 74 | DEFINE_FPREG (10); |
| 75 | |
| 76 | #undef DEFINE_FPREG |
| 77 | |
| 78 | |
| 79 | /* The return value is a structure and is actually stored in stack space |
| 80 | passed in a hidden argument by the caller. But, the compiler |
| 81 | helpfully returns the address of that space in r8. */ |
| 82 | static const Dwarf_Op loc_aggregate[] = |
| 83 | { |
| 84 | { .atom = DW_OP_breg8, .number = 0 } |
| 85 | }; |
| 86 | #define nloc_aggregate 1 |
| 87 | |
| 88 | |
| 89 | /* If this type is an HFA small enough to be returned in FP registers, |
| 90 | return the number of registers to use. Otherwise 9, or -1 for errors. */ |
| 91 | static int |
| 92 | hfa_type (Dwarf_Die *typedie, const Dwarf_Op **locp, int fpregs_used) |
| 93 | { |
| 94 | /* Descend the type structure, counting elements and finding their types. |
| 95 | If we find a datum that's not an FP type (and not quad FP), punt. |
| 96 | If we find a datum that's not the same FP type as the first datum, punt. |
| 97 | If we count more than eight total homogeneous FP data, punt. */ |
| 98 | |
| 99 | inline int hfa (const Dwarf_Op *loc, int nregs) |
| 100 | { |
| 101 | if (fpregs_used == 0) |
| 102 | *locp = loc; |
| 103 | else if (*locp != loc) |
| 104 | return 9; |
| 105 | return fpregs_used + nregs; |
| 106 | } |
| 107 | |
| 108 | int tag = dwarf_tag (typedie); |
| 109 | switch (tag) |
| 110 | { |
| 111 | Dwarf_Attribute attr_mem; |
| 112 | |
| 113 | case -1: |
| 114 | return -1; |
| 115 | |
| 116 | case DW_TAG_base_type:; |
| 117 | int size = dwarf_bytesize (typedie); |
| 118 | if (size < 0) |
| 119 | return -1; |
| 120 | |
| 121 | Dwarf_Word encoding; |
| 122 | if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, |
| 123 | &attr_mem), &encoding) != 0) |
| 124 | return -1; |
| 125 | |
| 126 | switch (encoding) |
| 127 | { |
| 128 | case DW_ATE_float: |
| 129 | switch (size) |
| 130 | { |
| 131 | case 4: /* float */ |
| 132 | return hfa (loc_fpreg_4, 1); |
| 133 | case 8: /* double */ |
| 134 | return hfa (loc_fpreg_8, 1); |
| 135 | case 10: /* x86-style long double, not really used */ |
| 136 | return hfa (loc_fpreg_10, 1); |
| 137 | } |
| 138 | break; |
| 139 | |
| 140 | case DW_ATE_complex_float: |
| 141 | switch (size) |
| 142 | { |
| 143 | case 4 * 2: /* complex float */ |
| 144 | return hfa (loc_fpreg_4, 2); |
| 145 | case 8 * 2: /* complex double */ |
| 146 | return hfa (loc_fpreg_8, 2); |
| 147 | case 10 * 2: /* complex long double (x86-style) */ |
| 148 | return hfa (loc_fpreg_10, 2); |
| 149 | } |
| 150 | break; |
| 151 | } |
| 152 | break; |
| 153 | |
| 154 | case DW_TAG_structure_type: |
| 155 | case DW_TAG_class_type: |
| 156 | case DW_TAG_union_type:; |
| 157 | Dwarf_Die child_mem; |
| 158 | switch (dwarf_child (typedie, &child_mem)) |
| 159 | { |
| 160 | default: |
| 161 | return -1; |
| 162 | |
| 163 | case 1: /* No children: empty struct. */ |
| 164 | break; |
| 165 | |
| 166 | case 0:; /* Look at each element. */ |
| 167 | int max_used = fpregs_used; |
| 168 | do |
| 169 | switch (dwarf_tag (&child_mem)) |
| 170 | { |
| 171 | case -1: |
| 172 | return -1; |
| 173 | |
| 174 | case DW_TAG_member:; |
| 175 | Dwarf_Die child_type_mem; |
| 176 | Dwarf_Die *child_typedie |
| 177 | = dwarf_formref_die (dwarf_attr_integrate (&child_mem, |
| 178 | DW_AT_type, |
| 179 | &attr_mem), |
| 180 | &child_type_mem); |
| 181 | if (tag == DW_TAG_union_type) |
| 182 | { |
| 183 | int used = hfa_type (child_typedie, locp, fpregs_used); |
| 184 | if (used < 0 || used > 8) |
| 185 | return used; |
| 186 | if (used > max_used) |
| 187 | max_used = used; |
| 188 | } |
| 189 | else |
| 190 | { |
| 191 | fpregs_used = hfa_type (child_typedie, locp, fpregs_used); |
| 192 | if (fpregs_used < 0 || fpregs_used > 8) |
| 193 | return fpregs_used; |
| 194 | } |
| 195 | } |
| 196 | while (dwarf_siblingof (&child_mem, &child_mem) == 0); |
| 197 | if (tag == DW_TAG_union_type) |
| 198 | fpregs_used = max_used; |
| 199 | break; |
| 200 | } |
| 201 | break; |
| 202 | |
| 203 | case DW_TAG_array_type:; |
| 204 | size = dwarf_bytesize (typedie); |
| 205 | if (size < 0) |
| 206 | return 9; |
| 207 | if (size == 0) |
| 208 | break; |
| 209 | |
| 210 | Dwarf_Die base_type_mem; |
| 211 | Dwarf_Die *base_typedie |
| 212 | = dwarf_formref_die (dwarf_attr_integrate (typedie, DW_AT_type, |
| 213 | &attr_mem), |
| 214 | &base_type_mem); |
| 215 | |
| 216 | int used = hfa_type (base_typedie, locp, 0); |
| 217 | if (used < 0 || used > 8) |
| 218 | return used; |
| 219 | if (size % (*locp)[1].number != 0) |
| 220 | return 0; |
| 221 | size /= (*locp)[1].number; |
| 222 | fpregs_used += used * size; |
| 223 | break; |
| 224 | |
| 225 | default: |
| 226 | return 9; |
| 227 | } |
| 228 | |
| 229 | return fpregs_used; |
| 230 | } |
| 231 | |
| 232 | int |
| 233 | ia64_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| 234 | { |
| 235 | /* Start with the function's type, and get the DW_AT_type attribute, |
| 236 | which is the type of the return value. */ |
| 237 | |
| 238 | Dwarf_Attribute attr_mem; |
| 239 | Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type, |
| 240 | &attr_mem); |
| 241 | if (attr == NULL) |
| 242 | /* The function has no return value, like a `void' function in C. */ |
| 243 | return 0; |
| 244 | |
| 245 | Dwarf_Die die_mem; |
| 246 | Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem); |
| 247 | int tag = dwarf_tag (typedie); |
| 248 | |
| 249 | /* Follow typedefs and qualifiers to get to the actual type. */ |
| 250 | while (tag == DW_TAG_typedef |
| 251 | || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type |
| 252 | || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type) |
| 253 | { |
| 254 | attr = dwarf_attr (typedie, DW_AT_type, &attr_mem); |
| 255 | typedie = dwarf_formref_die (attr, &die_mem); |
| 256 | tag = dwarf_tag (typedie); |
| 257 | } |
| 258 | |
| 259 | Dwarf_Word size; |
| 260 | switch (tag) |
| 261 | { |
| 262 | case -1: |
| 263 | return -1; |
| 264 | |
| 265 | case DW_TAG_subrange_type: |
| 266 | if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) |
| 267 | { |
| 268 | attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); |
| 269 | typedie = dwarf_formref_die (attr, &die_mem); |
| 270 | tag = dwarf_tag (typedie); |
| 271 | } |
| 272 | /* Fall through. */ |
| 273 | |
| 274 | case DW_TAG_base_type: |
| 275 | case DW_TAG_enumeration_type: |
| 276 | case DW_TAG_pointer_type: |
| 277 | case DW_TAG_ptr_to_member_type: |
| 278 | if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, |
| 279 | &attr_mem), &size) != 0) |
| 280 | { |
| 281 | if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) |
| 282 | size = 8; |
| 283 | else |
| 284 | return -1; |
| 285 | } |
| 286 | if (tag == DW_TAG_base_type) |
| 287 | { |
| 288 | Dwarf_Word encoding; |
| 289 | if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, |
| 290 | &attr_mem), |
| 291 | &encoding) != 0) |
| 292 | return -1; |
| 293 | |
| 294 | switch (encoding) |
| 295 | { |
| 296 | case DW_ATE_float: |
| 297 | switch (size) |
| 298 | { |
| 299 | case 4: /* float */ |
| 300 | *locp = loc_fpreg_4; |
| 301 | return nloc_fpreg; |
| 302 | case 8: /* double */ |
| 303 | *locp = loc_fpreg_8; |
| 304 | return nloc_fpreg; |
| 305 | case 10: /* x86-style long double, not really used */ |
| 306 | *locp = loc_fpreg_10; |
| 307 | return nloc_fpreg; |
| 308 | case 16: /* long double, IEEE quad format */ |
| 309 | *locp = loc_intreg; |
| 310 | return nloc_intregs (2); |
| 311 | } |
| 312 | return -2; |
| 313 | |
| 314 | case DW_ATE_complex_float: |
| 315 | switch (size) |
| 316 | { |
| 317 | case 4 * 2: /* complex float */ |
| 318 | *locp = loc_fpreg_4; |
| 319 | return nloc_fpregs (2); |
| 320 | case 8 * 2: /* complex double */ |
| 321 | *locp = loc_fpreg_8; |
| 322 | return nloc_fpregs (2); |
| 323 | case 10 * 2: /* complex long double (x86-style) */ |
| 324 | *locp = loc_fpreg_10; |
| 325 | return nloc_fpregs (2); |
| 326 | case 16 * 2: /* complex long double (IEEE quad) */ |
| 327 | *locp = loc_intreg; |
| 328 | return nloc_intregs (4); |
| 329 | } |
| 330 | return -2; |
| 331 | } |
| 332 | } |
| 333 | |
| 334 | intreg: |
| 335 | *locp = loc_intreg; |
| 336 | if (size <= 8) |
| 337 | return nloc_intreg; |
| 338 | if (size <= 32) |
| 339 | return nloc_intregs ((size + 7) / 8); |
| 340 | |
| 341 | large: |
| 342 | *locp = loc_aggregate; |
| 343 | return nloc_aggregate; |
| 344 | |
| 345 | case DW_TAG_structure_type: |
| 346 | case DW_TAG_class_type: |
| 347 | case DW_TAG_union_type: |
| 348 | case DW_TAG_array_type: |
| 349 | if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, |
| 350 | &attr_mem), &size) != 0) |
| 351 | return -1; |
| 352 | |
| 353 | /* If this qualifies as an homogeneous floating-point aggregate |
| 354 | (HFA), then it should be returned in FP regs. */ |
| 355 | int nfpreg = hfa_type (typedie, locp, 0); |
| 356 | if (nfpreg < 0) |
| 357 | return nfpreg; |
| 358 | else if (nfpreg > 0 && nfpreg <= 8) |
| 359 | return nfpreg == 1 ? nloc_fpreg : nloc_fpregs (nfpreg); |
| 360 | |
| 361 | if (size > 32) |
| 362 | goto large; |
| 363 | |
| 364 | goto intreg; |
| 365 | } |
| 366 | |
| 367 | /* XXX We don't have a good way to return specific errors from ebl calls. |
| 368 | This value means we do not understand the type, but it is well-formed |
| 369 | DWARF and might be valid. */ |
| 370 | return -2; |
| 371 | } |