| 1 | /* Native support code for PPC AIX, for GDB the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc. |
| 4 | |
| 5 | Free Software Foundation, Inc. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 3 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "gdb_string.h" |
| 24 | #include "gdb_assert.h" |
| 25 | #include "osabi.h" |
| 26 | #include "regcache.h" |
| 27 | #include "regset.h" |
| 28 | #include "gdbtypes.h" |
| 29 | #include "gdbcore.h" |
| 30 | #include "target.h" |
| 31 | #include "value.h" |
| 32 | #include "infcall.h" |
| 33 | #include "objfiles.h" |
| 34 | #include "breakpoint.h" |
| 35 | #include "rs6000-tdep.h" |
| 36 | #include "ppc-tdep.h" |
| 37 | |
| 38 | /* Hook for determining the TOC address when calling functions in the |
| 39 | inferior under AIX. The initialization code in rs6000-nat.c sets |
| 40 | this hook to point to find_toc_address. */ |
| 41 | |
| 42 | CORE_ADDR (*rs6000_find_toc_address_hook) (CORE_ADDR) = NULL; |
| 43 | |
| 44 | /* If the kernel has to deliver a signal, it pushes a sigcontext |
| 45 | structure on the stack and then calls the signal handler, passing |
| 46 | the address of the sigcontext in an argument register. Usually |
| 47 | the signal handler doesn't save this register, so we have to |
| 48 | access the sigcontext structure via an offset from the signal handler |
| 49 | frame. |
| 50 | The following constants were determined by experimentation on AIX 3.2. */ |
| 51 | #define SIG_FRAME_PC_OFFSET 96 |
| 52 | #define SIG_FRAME_LR_OFFSET 108 |
| 53 | #define SIG_FRAME_FP_OFFSET 284 |
| 54 | |
| 55 | |
| 56 | /* Core file support. */ |
| 57 | |
| 58 | static struct ppc_reg_offsets rs6000_aix32_reg_offsets = |
| 59 | { |
| 60 | /* General-purpose registers. */ |
| 61 | 208, /* r0_offset */ |
| 62 | 4, /* gpr_size */ |
| 63 | 4, /* xr_size */ |
| 64 | 24, /* pc_offset */ |
| 65 | 28, /* ps_offset */ |
| 66 | 32, /* cr_offset */ |
| 67 | 36, /* lr_offset */ |
| 68 | 40, /* ctr_offset */ |
| 69 | 44, /* xer_offset */ |
| 70 | 48, /* mq_offset */ |
| 71 | |
| 72 | /* Floating-point registers. */ |
| 73 | 336, /* f0_offset */ |
| 74 | 56, /* fpscr_offset */ |
| 75 | 4, /* fpscr_size */ |
| 76 | |
| 77 | /* AltiVec registers. */ |
| 78 | -1, /* vr0_offset */ |
| 79 | -1, /* vscr_offset */ |
| 80 | -1 /* vrsave_offset */ |
| 81 | }; |
| 82 | |
| 83 | static struct ppc_reg_offsets rs6000_aix64_reg_offsets = |
| 84 | { |
| 85 | /* General-purpose registers. */ |
| 86 | 0, /* r0_offset */ |
| 87 | 8, /* gpr_size */ |
| 88 | 4, /* xr_size */ |
| 89 | 264, /* pc_offset */ |
| 90 | 256, /* ps_offset */ |
| 91 | 288, /* cr_offset */ |
| 92 | 272, /* lr_offset */ |
| 93 | 280, /* ctr_offset */ |
| 94 | 292, /* xer_offset */ |
| 95 | -1, /* mq_offset */ |
| 96 | |
| 97 | /* Floating-point registers. */ |
| 98 | 312, /* f0_offset */ |
| 99 | 296, /* fpscr_offset */ |
| 100 | 4, /* fpscr_size */ |
| 101 | |
| 102 | /* AltiVec registers. */ |
| 103 | -1, /* vr0_offset */ |
| 104 | -1, /* vscr_offset */ |
| 105 | -1 /* vrsave_offset */ |
| 106 | }; |
| 107 | |
| 108 | |
| 109 | /* Supply register REGNUM in the general-purpose register set REGSET |
| 110 | from the buffer specified by GREGS and LEN to register cache |
| 111 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 112 | |
| 113 | static void |
| 114 | rs6000_aix_supply_regset (const struct regset *regset, |
| 115 | struct regcache *regcache, int regnum, |
| 116 | const void *gregs, size_t len) |
| 117 | { |
| 118 | ppc_supply_gregset (regset, regcache, regnum, gregs, len); |
| 119 | ppc_supply_fpregset (regset, regcache, regnum, gregs, len); |
| 120 | } |
| 121 | |
| 122 | /* Collect register REGNUM in the general-purpose register set |
| 123 | REGSET. from register cache REGCACHE into the buffer specified by |
| 124 | GREGS and LEN. If REGNUM is -1, do this for all registers in |
| 125 | REGSET. */ |
| 126 | |
| 127 | static void |
| 128 | rs6000_aix_collect_regset (const struct regset *regset, |
| 129 | const struct regcache *regcache, int regnum, |
| 130 | void *gregs, size_t len) |
| 131 | { |
| 132 | ppc_collect_gregset (regset, regcache, regnum, gregs, len); |
| 133 | ppc_collect_fpregset (regset, regcache, regnum, gregs, len); |
| 134 | } |
| 135 | |
| 136 | /* AIX register set. */ |
| 137 | |
| 138 | static struct regset rs6000_aix32_regset = |
| 139 | { |
| 140 | &rs6000_aix32_reg_offsets, |
| 141 | rs6000_aix_supply_regset, |
| 142 | rs6000_aix_collect_regset, |
| 143 | }; |
| 144 | |
| 145 | static struct regset rs6000_aix64_regset = |
| 146 | { |
| 147 | &rs6000_aix64_reg_offsets, |
| 148 | rs6000_aix_supply_regset, |
| 149 | rs6000_aix_collect_regset, |
| 150 | }; |
| 151 | |
| 152 | /* Return the appropriate register set for the core section identified |
| 153 | by SECT_NAME and SECT_SIZE. */ |
| 154 | |
| 155 | static const struct regset * |
| 156 | rs6000_aix_regset_from_core_section (struct gdbarch *gdbarch, |
| 157 | const char *sect_name, size_t sect_size) |
| 158 | { |
| 159 | if (gdbarch_tdep (gdbarch)->wordsize == 4) |
| 160 | { |
| 161 | if (strcmp (sect_name, ".reg") == 0 && sect_size >= 592) |
| 162 | return &rs6000_aix32_regset; |
| 163 | } |
| 164 | else |
| 165 | { |
| 166 | if (strcmp (sect_name, ".reg") == 0 && sect_size >= 576) |
| 167 | return &rs6000_aix64_regset; |
| 168 | } |
| 169 | |
| 170 | return NULL; |
| 171 | } |
| 172 | |
| 173 | |
| 174 | /* Pass the arguments in either registers, or in the stack. In RS/6000, |
| 175 | the first eight words of the argument list (that might be less than |
| 176 | eight parameters if some parameters occupy more than one word) are |
| 177 | passed in r3..r10 registers. float and double parameters are |
| 178 | passed in fpr's, in addition to that. Rest of the parameters if any |
| 179 | are passed in user stack. There might be cases in which half of the |
| 180 | parameter is copied into registers, the other half is pushed into |
| 181 | stack. |
| 182 | |
| 183 | Stack must be aligned on 64-bit boundaries when synthesizing |
| 184 | function calls. |
| 185 | |
| 186 | If the function is returning a structure, then the return address is passed |
| 187 | in r3, then the first 7 words of the parameters can be passed in registers, |
| 188 | starting from r4. */ |
| 189 | |
| 190 | static CORE_ADDR |
| 191 | rs6000_push_dummy_call (struct gdbarch *gdbarch, struct value *function, |
| 192 | struct regcache *regcache, CORE_ADDR bp_addr, |
| 193 | int nargs, struct value **args, CORE_ADDR sp, |
| 194 | int struct_return, CORE_ADDR struct_addr) |
| 195 | { |
| 196 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 197 | int ii; |
| 198 | int len = 0; |
| 199 | int argno; /* current argument number */ |
| 200 | int argbytes; /* current argument byte */ |
| 201 | gdb_byte tmp_buffer[50]; |
| 202 | int f_argno = 0; /* current floating point argno */ |
| 203 | int wordsize = gdbarch_tdep (gdbarch)->wordsize; |
| 204 | CORE_ADDR func_addr = find_function_addr (function, NULL); |
| 205 | |
| 206 | struct value *arg = 0; |
| 207 | struct type *type; |
| 208 | |
| 209 | ULONGEST saved_sp; |
| 210 | |
| 211 | /* The calling convention this function implements assumes the |
| 212 | processor has floating-point registers. We shouldn't be using it |
| 213 | on PPC variants that lack them. */ |
| 214 | gdb_assert (ppc_floating_point_unit_p (gdbarch)); |
| 215 | |
| 216 | /* The first eight words of ther arguments are passed in registers. |
| 217 | Copy them appropriately. */ |
| 218 | ii = 0; |
| 219 | |
| 220 | /* If the function is returning a `struct', then the first word |
| 221 | (which will be passed in r3) is used for struct return address. |
| 222 | In that case we should advance one word and start from r4 |
| 223 | register to copy parameters. */ |
| 224 | if (struct_return) |
| 225 | { |
| 226 | regcache_raw_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3, |
| 227 | struct_addr); |
| 228 | ii++; |
| 229 | } |
| 230 | |
| 231 | /* |
| 232 | effectively indirect call... gcc does... |
| 233 | |
| 234 | return_val example( float, int); |
| 235 | |
| 236 | eabi: |
| 237 | float in fp0, int in r3 |
| 238 | offset of stack on overflow 8/16 |
| 239 | for varargs, must go by type. |
| 240 | power open: |
| 241 | float in r3&r4, int in r5 |
| 242 | offset of stack on overflow different |
| 243 | both: |
| 244 | return in r3 or f0. If no float, must study how gcc emulates floats; |
| 245 | pay attention to arg promotion. |
| 246 | User may have to cast\args to handle promotion correctly |
| 247 | since gdb won't know if prototype supplied or not. |
| 248 | */ |
| 249 | |
| 250 | for (argno = 0, argbytes = 0; argno < nargs && ii < 8; ++ii) |
| 251 | { |
| 252 | int reg_size = register_size (gdbarch, ii + 3); |
| 253 | |
| 254 | arg = args[argno]; |
| 255 | type = check_typedef (value_type (arg)); |
| 256 | len = TYPE_LENGTH (type); |
| 257 | |
| 258 | if (TYPE_CODE (type) == TYPE_CODE_FLT) |
| 259 | { |
| 260 | |
| 261 | /* Floating point arguments are passed in fpr's, as well as gpr's. |
| 262 | There are 13 fpr's reserved for passing parameters. At this point |
| 263 | there is no way we would run out of them. */ |
| 264 | |
| 265 | gdb_assert (len <= 8); |
| 266 | |
| 267 | regcache_cooked_write (regcache, |
| 268 | tdep->ppc_fp0_regnum + 1 + f_argno, |
| 269 | value_contents (arg)); |
| 270 | ++f_argno; |
| 271 | } |
| 272 | |
| 273 | if (len > reg_size) |
| 274 | { |
| 275 | |
| 276 | /* Argument takes more than one register. */ |
| 277 | while (argbytes < len) |
| 278 | { |
| 279 | gdb_byte word[MAX_REGISTER_SIZE]; |
| 280 | memset (word, 0, reg_size); |
| 281 | memcpy (word, |
| 282 | ((char *) value_contents (arg)) + argbytes, |
| 283 | (len - argbytes) > reg_size |
| 284 | ? reg_size : len - argbytes); |
| 285 | regcache_cooked_write (regcache, |
| 286 | tdep->ppc_gp0_regnum + 3 + ii, |
| 287 | word); |
| 288 | ++ii, argbytes += reg_size; |
| 289 | |
| 290 | if (ii >= 8) |
| 291 | goto ran_out_of_registers_for_arguments; |
| 292 | } |
| 293 | argbytes = 0; |
| 294 | --ii; |
| 295 | } |
| 296 | else |
| 297 | { |
| 298 | /* Argument can fit in one register. No problem. */ |
| 299 | int adj = gdbarch_byte_order (gdbarch) |
| 300 | == BFD_ENDIAN_BIG ? reg_size - len : 0; |
| 301 | gdb_byte word[MAX_REGISTER_SIZE]; |
| 302 | |
| 303 | memset (word, 0, reg_size); |
| 304 | memcpy (word, value_contents (arg), len); |
| 305 | regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3 +ii, word); |
| 306 | } |
| 307 | ++argno; |
| 308 | } |
| 309 | |
| 310 | ran_out_of_registers_for_arguments: |
| 311 | |
| 312 | regcache_cooked_read_unsigned (regcache, |
| 313 | gdbarch_sp_regnum (gdbarch), |
| 314 | &saved_sp); |
| 315 | |
| 316 | /* Location for 8 parameters are always reserved. */ |
| 317 | sp -= wordsize * 8; |
| 318 | |
| 319 | /* Another six words for back chain, TOC register, link register, etc. */ |
| 320 | sp -= wordsize * 6; |
| 321 | |
| 322 | /* Stack pointer must be quadword aligned. */ |
| 323 | sp &= -16; |
| 324 | |
| 325 | /* If there are more arguments, allocate space for them in |
| 326 | the stack, then push them starting from the ninth one. */ |
| 327 | |
| 328 | if ((argno < nargs) || argbytes) |
| 329 | { |
| 330 | int space = 0, jj; |
| 331 | |
| 332 | if (argbytes) |
| 333 | { |
| 334 | space += ((len - argbytes + 3) & -4); |
| 335 | jj = argno + 1; |
| 336 | } |
| 337 | else |
| 338 | jj = argno; |
| 339 | |
| 340 | for (; jj < nargs; ++jj) |
| 341 | { |
| 342 | struct value *val = args[jj]; |
| 343 | space += ((TYPE_LENGTH (value_type (val))) + 3) & -4; |
| 344 | } |
| 345 | |
| 346 | /* Add location required for the rest of the parameters. */ |
| 347 | space = (space + 15) & -16; |
| 348 | sp -= space; |
| 349 | |
| 350 | /* This is another instance we need to be concerned about |
| 351 | securing our stack space. If we write anything underneath %sp |
| 352 | (r1), we might conflict with the kernel who thinks he is free |
| 353 | to use this area. So, update %sp first before doing anything |
| 354 | else. */ |
| 355 | |
| 356 | regcache_raw_write_signed (regcache, |
| 357 | gdbarch_sp_regnum (gdbarch), sp); |
| 358 | |
| 359 | /* If the last argument copied into the registers didn't fit there |
| 360 | completely, push the rest of it into stack. */ |
| 361 | |
| 362 | if (argbytes) |
| 363 | { |
| 364 | write_memory (sp + 24 + (ii * 4), |
| 365 | value_contents (arg) + argbytes, |
| 366 | len - argbytes); |
| 367 | ++argno; |
| 368 | ii += ((len - argbytes + 3) & -4) / 4; |
| 369 | } |
| 370 | |
| 371 | /* Push the rest of the arguments into stack. */ |
| 372 | for (; argno < nargs; ++argno) |
| 373 | { |
| 374 | |
| 375 | arg = args[argno]; |
| 376 | type = check_typedef (value_type (arg)); |
| 377 | len = TYPE_LENGTH (type); |
| 378 | |
| 379 | |
| 380 | /* Float types should be passed in fpr's, as well as in the |
| 381 | stack. */ |
| 382 | if (TYPE_CODE (type) == TYPE_CODE_FLT && f_argno < 13) |
| 383 | { |
| 384 | |
| 385 | gdb_assert (len <= 8); |
| 386 | |
| 387 | regcache_cooked_write (regcache, |
| 388 | tdep->ppc_fp0_regnum + 1 + f_argno, |
| 389 | value_contents (arg)); |
| 390 | ++f_argno; |
| 391 | } |
| 392 | |
| 393 | write_memory (sp + 24 + (ii * 4), value_contents (arg), len); |
| 394 | ii += ((len + 3) & -4) / 4; |
| 395 | } |
| 396 | } |
| 397 | |
| 398 | /* Set the stack pointer. According to the ABI, the SP is meant to |
| 399 | be set _before_ the corresponding stack space is used. On AIX, |
| 400 | this even applies when the target has been completely stopped! |
| 401 | Not doing this can lead to conflicts with the kernel which thinks |
| 402 | that it still has control over this not-yet-allocated stack |
| 403 | region. */ |
| 404 | regcache_raw_write_signed (regcache, gdbarch_sp_regnum (gdbarch), sp); |
| 405 | |
| 406 | /* Set back chain properly. */ |
| 407 | store_unsigned_integer (tmp_buffer, wordsize, saved_sp); |
| 408 | write_memory (sp, tmp_buffer, wordsize); |
| 409 | |
| 410 | /* Point the inferior function call's return address at the dummy's |
| 411 | breakpoint. */ |
| 412 | regcache_raw_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr); |
| 413 | |
| 414 | /* Set the TOC register, get the value from the objfile reader |
| 415 | which, in turn, gets it from the VMAP table. */ |
| 416 | if (rs6000_find_toc_address_hook != NULL) |
| 417 | { |
| 418 | CORE_ADDR tocvalue = (*rs6000_find_toc_address_hook) (func_addr); |
| 419 | regcache_raw_write_signed (regcache, tdep->ppc_toc_regnum, tocvalue); |
| 420 | } |
| 421 | |
| 422 | target_store_registers (regcache, -1); |
| 423 | return sp; |
| 424 | } |
| 425 | |
| 426 | static enum return_value_convention |
| 427 | rs6000_return_value (struct gdbarch *gdbarch, struct type *func_type, |
| 428 | struct type *valtype, struct regcache *regcache, |
| 429 | gdb_byte *readbuf, const gdb_byte *writebuf) |
| 430 | { |
| 431 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 432 | gdb_byte buf[8]; |
| 433 | |
| 434 | /* The calling convention this function implements assumes the |
| 435 | processor has floating-point registers. We shouldn't be using it |
| 436 | on PowerPC variants that lack them. */ |
| 437 | gdb_assert (ppc_floating_point_unit_p (gdbarch)); |
| 438 | |
| 439 | /* AltiVec extension: Functions that declare a vector data type as a |
| 440 | return value place that return value in VR2. */ |
| 441 | if (TYPE_CODE (valtype) == TYPE_CODE_ARRAY && TYPE_VECTOR (valtype) |
| 442 | && TYPE_LENGTH (valtype) == 16) |
| 443 | { |
| 444 | if (readbuf) |
| 445 | regcache_cooked_read (regcache, tdep->ppc_vr0_regnum + 2, readbuf); |
| 446 | if (writebuf) |
| 447 | regcache_cooked_write (regcache, tdep->ppc_vr0_regnum + 2, writebuf); |
| 448 | |
| 449 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 450 | } |
| 451 | |
| 452 | /* If the called subprogram returns an aggregate, there exists an |
| 453 | implicit first argument, whose value is the address of a caller- |
| 454 | allocated buffer into which the callee is assumed to store its |
| 455 | return value. All explicit parameters are appropriately |
| 456 | relabeled. */ |
| 457 | if (TYPE_CODE (valtype) == TYPE_CODE_STRUCT |
| 458 | || TYPE_CODE (valtype) == TYPE_CODE_UNION |
| 459 | || TYPE_CODE (valtype) == TYPE_CODE_ARRAY) |
| 460 | return RETURN_VALUE_STRUCT_CONVENTION; |
| 461 | |
| 462 | /* Scalar floating-point values are returned in FPR1 for float or |
| 463 | double, and in FPR1:FPR2 for quadword precision. Fortran |
| 464 | complex*8 and complex*16 are returned in FPR1:FPR2, and |
| 465 | complex*32 is returned in FPR1:FPR4. */ |
| 466 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT |
| 467 | && (TYPE_LENGTH (valtype) == 4 || TYPE_LENGTH (valtype) == 8)) |
| 468 | { |
| 469 | struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum); |
| 470 | gdb_byte regval[8]; |
| 471 | |
| 472 | /* FIXME: kettenis/2007-01-01: Add support for quadword |
| 473 | precision and complex. */ |
| 474 | |
| 475 | if (readbuf) |
| 476 | { |
| 477 | regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1, regval); |
| 478 | convert_typed_floating (regval, regtype, readbuf, valtype); |
| 479 | } |
| 480 | if (writebuf) |
| 481 | { |
| 482 | convert_typed_floating (writebuf, valtype, regval, regtype); |
| 483 | regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1, regval); |
| 484 | } |
| 485 | |
| 486 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 487 | } |
| 488 | |
| 489 | /* Values of the types int, long, short, pointer, and char (length |
| 490 | is less than or equal to four bytes), as well as bit values of |
| 491 | lengths less than or equal to 32 bits, must be returned right |
| 492 | justified in GPR3 with signed values sign extended and unsigned |
| 493 | values zero extended, as necessary. */ |
| 494 | if (TYPE_LENGTH (valtype) <= tdep->wordsize) |
| 495 | { |
| 496 | if (readbuf) |
| 497 | { |
| 498 | ULONGEST regval; |
| 499 | |
| 500 | /* For reading we don't have to worry about sign extension. */ |
| 501 | regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3, |
| 502 | ®val); |
| 503 | store_unsigned_integer (readbuf, TYPE_LENGTH (valtype), regval); |
| 504 | } |
| 505 | if (writebuf) |
| 506 | { |
| 507 | /* For writing, use unpack_long since that should handle any |
| 508 | required sign extension. */ |
| 509 | regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3, |
| 510 | unpack_long (valtype, writebuf)); |
| 511 | } |
| 512 | |
| 513 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 514 | } |
| 515 | |
| 516 | /* Eight-byte non-floating-point scalar values must be returned in |
| 517 | GPR3:GPR4. */ |
| 518 | |
| 519 | if (TYPE_LENGTH (valtype) == 8) |
| 520 | { |
| 521 | gdb_assert (TYPE_CODE (valtype) != TYPE_CODE_FLT); |
| 522 | gdb_assert (tdep->wordsize == 4); |
| 523 | |
| 524 | if (readbuf) |
| 525 | { |
| 526 | gdb_byte regval[8]; |
| 527 | |
| 528 | regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3, regval); |
| 529 | regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 4, |
| 530 | regval + 4); |
| 531 | memcpy (readbuf, regval, 8); |
| 532 | } |
| 533 | if (writebuf) |
| 534 | { |
| 535 | regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3, writebuf); |
| 536 | regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 4, |
| 537 | writebuf + 4); |
| 538 | } |
| 539 | |
| 540 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 541 | } |
| 542 | |
| 543 | return RETURN_VALUE_STRUCT_CONVENTION; |
| 544 | } |
| 545 | |
| 546 | /* Support for CONVERT_FROM_FUNC_PTR_ADDR (ARCH, ADDR, TARG). |
| 547 | |
| 548 | Usually a function pointer's representation is simply the address |
| 549 | of the function. On the RS/6000 however, a function pointer is |
| 550 | represented by a pointer to an OPD entry. This OPD entry contains |
| 551 | three words, the first word is the address of the function, the |
| 552 | second word is the TOC pointer (r2), and the third word is the |
| 553 | static chain value. Throughout GDB it is currently assumed that a |
| 554 | function pointer contains the address of the function, which is not |
| 555 | easy to fix. In addition, the conversion of a function address to |
| 556 | a function pointer would require allocation of an OPD entry in the |
| 557 | inferior's memory space, with all its drawbacks. To be able to |
| 558 | call C++ virtual methods in the inferior (which are called via |
| 559 | function pointers), find_function_addr uses this function to get the |
| 560 | function address from a function pointer. */ |
| 561 | |
| 562 | /* Return real function address if ADDR (a function pointer) is in the data |
| 563 | space and is therefore a special function pointer. */ |
| 564 | |
| 565 | static CORE_ADDR |
| 566 | rs6000_convert_from_func_ptr_addr (struct gdbarch *gdbarch, |
| 567 | CORE_ADDR addr, |
| 568 | struct target_ops *targ) |
| 569 | { |
| 570 | struct obj_section *s; |
| 571 | |
| 572 | s = find_pc_section (addr); |
| 573 | |
| 574 | /* Normally, functions live inside a section that is executable. |
| 575 | So, if ADDR points to a non-executable section, then treat it |
| 576 | as a function descriptor and return the target address iff |
| 577 | the target address itself points to a section that is executable. */ |
| 578 | if (s && (s->the_bfd_section->flags & SEC_CODE) == 0) |
| 579 | { |
| 580 | CORE_ADDR pc = |
| 581 | read_memory_unsigned_integer (addr, gdbarch_tdep (gdbarch)->wordsize); |
| 582 | struct obj_section *pc_section = find_pc_section (pc); |
| 583 | |
| 584 | if (pc_section && (pc_section->the_bfd_section->flags & SEC_CODE)) |
| 585 | return pc; |
| 586 | } |
| 587 | |
| 588 | return addr; |
| 589 | } |
| 590 | |
| 591 | |
| 592 | /* Calculate the destination of a branch/jump. Return -1 if not a branch. */ |
| 593 | |
| 594 | static CORE_ADDR |
| 595 | branch_dest (struct frame_info *frame, int opcode, int instr, |
| 596 | CORE_ADDR pc, CORE_ADDR safety) |
| 597 | { |
| 598 | struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (frame)); |
| 599 | CORE_ADDR dest; |
| 600 | int immediate; |
| 601 | int absolute; |
| 602 | int ext_op; |
| 603 | |
| 604 | absolute = (int) ((instr >> 1) & 1); |
| 605 | |
| 606 | switch (opcode) |
| 607 | { |
| 608 | case 18: |
| 609 | immediate = ((instr & ~3) << 6) >> 6; /* br unconditional */ |
| 610 | if (absolute) |
| 611 | dest = immediate; |
| 612 | else |
| 613 | dest = pc + immediate; |
| 614 | break; |
| 615 | |
| 616 | case 16: |
| 617 | immediate = ((instr & ~3) << 16) >> 16; /* br conditional */ |
| 618 | if (absolute) |
| 619 | dest = immediate; |
| 620 | else |
| 621 | dest = pc + immediate; |
| 622 | break; |
| 623 | |
| 624 | case 19: |
| 625 | ext_op = (instr >> 1) & 0x3ff; |
| 626 | |
| 627 | if (ext_op == 16) /* br conditional register */ |
| 628 | { |
| 629 | dest = get_frame_register_unsigned (frame, tdep->ppc_lr_regnum) & ~3; |
| 630 | |
| 631 | /* If we are about to return from a signal handler, dest is |
| 632 | something like 0x3c90. The current frame is a signal handler |
| 633 | caller frame, upon completion of the sigreturn system call |
| 634 | execution will return to the saved PC in the frame. */ |
| 635 | if (dest < AIX_TEXT_SEGMENT_BASE) |
| 636 | dest = read_memory_unsigned_integer |
| 637 | (get_frame_base (frame) + SIG_FRAME_PC_OFFSET, |
| 638 | tdep->wordsize); |
| 639 | } |
| 640 | |
| 641 | else if (ext_op == 528) /* br cond to count reg */ |
| 642 | { |
| 643 | dest = get_frame_register_unsigned (frame, tdep->ppc_ctr_regnum) & ~3; |
| 644 | |
| 645 | /* If we are about to execute a system call, dest is something |
| 646 | like 0x22fc or 0x3b00. Upon completion the system call |
| 647 | will return to the address in the link register. */ |
| 648 | if (dest < AIX_TEXT_SEGMENT_BASE) |
| 649 | dest = get_frame_register_unsigned (frame, tdep->ppc_lr_regnum) & ~3; |
| 650 | } |
| 651 | else |
| 652 | return -1; |
| 653 | break; |
| 654 | |
| 655 | default: |
| 656 | return -1; |
| 657 | } |
| 658 | return (dest < AIX_TEXT_SEGMENT_BASE) ? safety : dest; |
| 659 | } |
| 660 | |
| 661 | /* AIX does not support PT_STEP. Simulate it. */ |
| 662 | |
| 663 | static int |
| 664 | rs6000_software_single_step (struct frame_info *frame) |
| 665 | { |
| 666 | int ii, insn; |
| 667 | CORE_ADDR loc; |
| 668 | CORE_ADDR breaks[2]; |
| 669 | int opcode; |
| 670 | |
| 671 | loc = get_frame_pc (frame); |
| 672 | |
| 673 | insn = read_memory_integer (loc, 4); |
| 674 | |
| 675 | if (ppc_deal_with_atomic_sequence (frame)) |
| 676 | return 1; |
| 677 | |
| 678 | breaks[0] = loc + PPC_INSN_SIZE; |
| 679 | opcode = insn >> 26; |
| 680 | breaks[1] = branch_dest (frame, opcode, insn, loc, breaks[0]); |
| 681 | |
| 682 | /* Don't put two breakpoints on the same address. */ |
| 683 | if (breaks[1] == breaks[0]) |
| 684 | breaks[1] = -1; |
| 685 | |
| 686 | for (ii = 0; ii < 2; ++ii) |
| 687 | { |
| 688 | /* ignore invalid breakpoint. */ |
| 689 | if (breaks[ii] == -1) |
| 690 | continue; |
| 691 | insert_single_step_breakpoint (breaks[ii]); |
| 692 | } |
| 693 | |
| 694 | errno = 0; /* FIXME, don't ignore errors! */ |
| 695 | /* What errors? {read,write}_memory call error(). */ |
| 696 | return 1; |
| 697 | } |
| 698 | |
| 699 | static enum gdb_osabi |
| 700 | rs6000_aix_osabi_sniffer (bfd *abfd) |
| 701 | { |
| 702 | |
| 703 | if (bfd_get_flavour (abfd) == bfd_target_xcoff_flavour); |
| 704 | return GDB_OSABI_AIX; |
| 705 | |
| 706 | return GDB_OSABI_UNKNOWN; |
| 707 | } |
| 708 | |
| 709 | static void |
| 710 | rs6000_aix_init_osabi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 711 | { |
| 712 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 713 | |
| 714 | /* RS6000/AIX does not support PT_STEP. Has to be simulated. */ |
| 715 | set_gdbarch_software_single_step (gdbarch, rs6000_software_single_step); |
| 716 | |
| 717 | /* Displaced stepping is currently not supported in combination with |
| 718 | software single-stepping. */ |
| 719 | set_gdbarch_displaced_step_copy_insn (gdbarch, NULL); |
| 720 | set_gdbarch_displaced_step_fixup (gdbarch, NULL); |
| 721 | set_gdbarch_displaced_step_free_closure (gdbarch, NULL); |
| 722 | set_gdbarch_displaced_step_location (gdbarch, NULL); |
| 723 | |
| 724 | set_gdbarch_push_dummy_call (gdbarch, rs6000_push_dummy_call); |
| 725 | set_gdbarch_return_value (gdbarch, rs6000_return_value); |
| 726 | set_gdbarch_long_double_bit (gdbarch, 8 * TARGET_CHAR_BIT); |
| 727 | |
| 728 | /* Handle RS/6000 function pointers (which are really function |
| 729 | descriptors). */ |
| 730 | set_gdbarch_convert_from_func_ptr_addr |
| 731 | (gdbarch, rs6000_convert_from_func_ptr_addr); |
| 732 | |
| 733 | /* Core file support. */ |
| 734 | set_gdbarch_regset_from_core_section |
| 735 | (gdbarch, rs6000_aix_regset_from_core_section); |
| 736 | |
| 737 | if (tdep->wordsize == 8) |
| 738 | tdep->lr_frame_offset = 16; |
| 739 | else |
| 740 | tdep->lr_frame_offset = 8; |
| 741 | |
| 742 | if (tdep->wordsize == 4) |
| 743 | /* PowerOpen / AIX 32 bit. The saved area or red zone consists of |
| 744 | 19 4 byte GPRS + 18 8 byte FPRs giving a total of 220 bytes. |
| 745 | Problem is, 220 isn't frame (16 byte) aligned. Round it up to |
| 746 | 224. */ |
| 747 | set_gdbarch_frame_red_zone_size (gdbarch, 224); |
| 748 | else |
| 749 | set_gdbarch_frame_red_zone_size (gdbarch, 0); |
| 750 | } |
| 751 | |
| 752 | void |
| 753 | _initialize_rs6000_aix_tdep (void) |
| 754 | { |
| 755 | gdbarch_register_osabi_sniffer (bfd_arch_rs6000, |
| 756 | bfd_target_xcoff_flavour, |
| 757 | rs6000_aix_osabi_sniffer); |
| 758 | gdbarch_register_osabi_sniffer (bfd_arch_powerpc, |
| 759 | bfd_target_xcoff_flavour, |
| 760 | rs6000_aix_osabi_sniffer); |
| 761 | |
| 762 | gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_AIX, |
| 763 | rs6000_aix_init_osabi); |
| 764 | gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_AIX, |
| 765 | rs6000_aix_init_osabi); |
| 766 | } |
| 767 | |