| 1 | /* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger. |
| 2 | Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001 |
| 3 | Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 2 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program; if not, write to the Free Software |
| 19 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 20 | Boston, MA 02111-1307, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "frame.h" |
| 24 | #include "inferior.h" |
| 25 | #include "symtab.h" |
| 26 | #include "value.h" |
| 27 | #include "gdbcmd.h" |
| 28 | #include "gdbcore.h" |
| 29 | #include "dis-asm.h" |
| 30 | #include "symfile.h" |
| 31 | #include "objfiles.h" |
| 32 | #include "gdb_string.h" |
| 33 | #include "linespec.h" |
| 34 | #include "regcache.h" |
| 35 | #include "doublest.h" |
| 36 | |
| 37 | /* FIXME: Some of this code should perhaps be merged with mips-tdep.c. */ |
| 38 | |
| 39 | /* Prototypes for local functions. */ |
| 40 | |
| 41 | static alpha_extra_func_info_t push_sigtramp_desc (CORE_ADDR low_addr); |
| 42 | |
| 43 | static CORE_ADDR read_next_frame_reg (struct frame_info *, int); |
| 44 | |
| 45 | static CORE_ADDR heuristic_proc_start (CORE_ADDR); |
| 46 | |
| 47 | static alpha_extra_func_info_t heuristic_proc_desc (CORE_ADDR, |
| 48 | CORE_ADDR, |
| 49 | struct frame_info *); |
| 50 | |
| 51 | static alpha_extra_func_info_t find_proc_desc (CORE_ADDR, |
| 52 | struct frame_info *); |
| 53 | |
| 54 | #if 0 |
| 55 | static int alpha_in_lenient_prologue (CORE_ADDR, CORE_ADDR); |
| 56 | #endif |
| 57 | |
| 58 | static void reinit_frame_cache_sfunc (char *, int, struct cmd_list_element *); |
| 59 | |
| 60 | static CORE_ADDR after_prologue (CORE_ADDR pc, |
| 61 | alpha_extra_func_info_t proc_desc); |
| 62 | |
| 63 | static int alpha_in_prologue (CORE_ADDR pc, |
| 64 | alpha_extra_func_info_t proc_desc); |
| 65 | |
| 66 | static int alpha_about_to_return (CORE_ADDR pc); |
| 67 | |
| 68 | void _initialize_alpha_tdep (void); |
| 69 | |
| 70 | /* Heuristic_proc_start may hunt through the text section for a long |
| 71 | time across a 2400 baud serial line. Allows the user to limit this |
| 72 | search. */ |
| 73 | static unsigned int heuristic_fence_post = 0; |
| 74 | /* *INDENT-OFF* */ |
| 75 | /* Layout of a stack frame on the alpha: |
| 76 | |
| 77 | | | |
| 78 | pdr members: | 7th ... nth arg, | |
| 79 | | `pushed' by caller. | |
| 80 | | | |
| 81 | ----------------|-------------------------------|<-- old_sp == vfp |
| 82 | ^ ^ ^ ^ | | |
| 83 | | | | | | | |
| 84 | | |localoff | Copies of 1st .. 6th | |
| 85 | | | | | | argument if necessary. | |
| 86 | | | | v | | |
| 87 | | | | --- |-------------------------------|<-- FRAME_LOCALS_ADDRESS |
| 88 | | | | | | |
| 89 | | | | | Locals and temporaries. | |
| 90 | | | | | | |
| 91 | | | | |-------------------------------| |
| 92 | | | | | | |
| 93 | |-fregoffset | Saved float registers. | |
| 94 | | | | | F9 | |
| 95 | | | | | . | |
| 96 | | | | | . | |
| 97 | | | | | F2 | |
| 98 | | | v | | |
| 99 | | | -------|-------------------------------| |
| 100 | | | | | |
| 101 | | | | Saved registers. | |
| 102 | | | | S6 | |
| 103 | |-regoffset | . | |
| 104 | | | | . | |
| 105 | | | | S0 | |
| 106 | | | | pdr.pcreg | |
| 107 | | v | | |
| 108 | | ----------|-------------------------------| |
| 109 | | | | |
| 110 | frameoffset | Argument build area, gets | |
| 111 | | | 7th ... nth arg for any | |
| 112 | | | called procedure. | |
| 113 | v | | |
| 114 | -------------|-------------------------------|<-- sp |
| 115 | | | |
| 116 | */ |
| 117 | /* *INDENT-ON* */ |
| 118 | |
| 119 | |
| 120 | |
| 121 | #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */ |
| 122 | /* These next two fields are kind of being hijacked. I wonder if |
| 123 | iline is too small for the values it needs to hold, if GDB is |
| 124 | running on a 32-bit host. */ |
| 125 | #define PROC_HIGH_ADDR(proc) ((proc)->pdr.iline) /* upper address bound */ |
| 126 | #define PROC_DUMMY_FRAME(proc) ((proc)->pdr.cbLineOffset) /*CALL_DUMMY frame */ |
| 127 | #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset) |
| 128 | #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg) |
| 129 | #define PROC_REG_MASK(proc) ((proc)->pdr.regmask) |
| 130 | #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask) |
| 131 | #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset) |
| 132 | #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset) |
| 133 | #define PROC_PC_REG(proc) ((proc)->pdr.pcreg) |
| 134 | #define PROC_LOCALOFF(proc) ((proc)->pdr.localoff) |
| 135 | #define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym) |
| 136 | #define _PROC_MAGIC_ 0x0F0F0F0F |
| 137 | #define PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym == _PROC_MAGIC_) |
| 138 | #define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym = _PROC_MAGIC_) |
| 139 | |
| 140 | struct linked_proc_info |
| 141 | { |
| 142 | struct alpha_extra_func_info info; |
| 143 | struct linked_proc_info *next; |
| 144 | } |
| 145 | *linked_proc_desc_table = NULL; |
| 146 | \f |
| 147 | |
| 148 | /* Under GNU/Linux, signal handler invocations can be identified by the |
| 149 | designated code sequence that is used to return from a signal |
| 150 | handler. In particular, the return address of a signal handler |
| 151 | points to the following sequence (the first instruction is quadword |
| 152 | aligned): |
| 153 | |
| 154 | bis $30,$30,$16 |
| 155 | addq $31,0x67,$0 |
| 156 | call_pal callsys |
| 157 | |
| 158 | Each instruction has a unique encoding, so we simply attempt to |
| 159 | match the instruction the pc is pointing to with any of the above |
| 160 | instructions. If there is a hit, we know the offset to the start |
| 161 | of the designated sequence and can then check whether we really are |
| 162 | executing in a designated sequence. If not, -1 is returned, |
| 163 | otherwise the offset from the start of the desingated sequence is |
| 164 | returned. |
| 165 | |
| 166 | There is a slight chance of false hits: code could jump into the |
| 167 | middle of the designated sequence, in which case there is no |
| 168 | guarantee that we are in the middle of a sigreturn syscall. Don't |
| 169 | think this will be a problem in praxis, though. |
| 170 | */ |
| 171 | |
| 172 | #ifndef TM_LINUXALPHA_H |
| 173 | /* HACK: Provide a prototype when compiling this file for non |
| 174 | linuxalpha targets. */ |
| 175 | long alpha_linux_sigtramp_offset (CORE_ADDR pc); |
| 176 | #endif |
| 177 | long |
| 178 | alpha_linux_sigtramp_offset (CORE_ADDR pc) |
| 179 | { |
| 180 | unsigned int i[3], w; |
| 181 | long off; |
| 182 | |
| 183 | if (read_memory_nobpt (pc, (char *) &w, 4) != 0) |
| 184 | return -1; |
| 185 | |
| 186 | off = -1; |
| 187 | switch (w) |
| 188 | { |
| 189 | case 0x47de0410: |
| 190 | off = 0; |
| 191 | break; /* bis $30,$30,$16 */ |
| 192 | case 0x43ecf400: |
| 193 | off = 4; |
| 194 | break; /* addq $31,0x67,$0 */ |
| 195 | case 0x00000083: |
| 196 | off = 8; |
| 197 | break; /* call_pal callsys */ |
| 198 | default: |
| 199 | return -1; |
| 200 | } |
| 201 | pc -= off; |
| 202 | if (pc & 0x7) |
| 203 | { |
| 204 | /* designated sequence is not quadword aligned */ |
| 205 | return -1; |
| 206 | } |
| 207 | |
| 208 | if (read_memory_nobpt (pc, (char *) i, sizeof (i)) != 0) |
| 209 | return -1; |
| 210 | |
| 211 | if (i[0] == 0x47de0410 && i[1] == 0x43ecf400 && i[2] == 0x00000083) |
| 212 | return off; |
| 213 | |
| 214 | return -1; |
| 215 | } |
| 216 | \f |
| 217 | |
| 218 | /* Under OSF/1, the __sigtramp routine is frameless and has a frame |
| 219 | size of zero, but we are able to backtrace through it. */ |
| 220 | CORE_ADDR |
| 221 | alpha_osf_skip_sigtramp_frame (struct frame_info *frame, CORE_ADDR pc) |
| 222 | { |
| 223 | char *name; |
| 224 | find_pc_partial_function (pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL); |
| 225 | if (IN_SIGTRAMP (pc, name)) |
| 226 | return frame->frame; |
| 227 | else |
| 228 | return 0; |
| 229 | } |
| 230 | \f |
| 231 | |
| 232 | /* Dynamically create a signal-handler caller procedure descriptor for |
| 233 | the signal-handler return code starting at address LOW_ADDR. The |
| 234 | descriptor is added to the linked_proc_desc_table. */ |
| 235 | |
| 236 | static alpha_extra_func_info_t |
| 237 | push_sigtramp_desc (CORE_ADDR low_addr) |
| 238 | { |
| 239 | struct linked_proc_info *link; |
| 240 | alpha_extra_func_info_t proc_desc; |
| 241 | |
| 242 | link = (struct linked_proc_info *) |
| 243 | xmalloc (sizeof (struct linked_proc_info)); |
| 244 | link->next = linked_proc_desc_table; |
| 245 | linked_proc_desc_table = link; |
| 246 | |
| 247 | proc_desc = &link->info; |
| 248 | |
| 249 | proc_desc->numargs = 0; |
| 250 | PROC_LOW_ADDR (proc_desc) = low_addr; |
| 251 | PROC_HIGH_ADDR (proc_desc) = low_addr + 3 * 4; |
| 252 | PROC_DUMMY_FRAME (proc_desc) = 0; |
| 253 | PROC_FRAME_OFFSET (proc_desc) = 0x298; /* sizeof(struct sigcontext_struct) */ |
| 254 | PROC_FRAME_REG (proc_desc) = SP_REGNUM; |
| 255 | PROC_REG_MASK (proc_desc) = 0xffff; |
| 256 | PROC_FREG_MASK (proc_desc) = 0xffff; |
| 257 | PROC_PC_REG (proc_desc) = 26; |
| 258 | PROC_LOCALOFF (proc_desc) = 0; |
| 259 | SET_PROC_DESC_IS_DYN_SIGTRAMP (proc_desc); |
| 260 | return (proc_desc); |
| 261 | } |
| 262 | \f |
| 263 | |
| 264 | /* Guaranteed to set frame->saved_regs to some values (it never leaves it |
| 265 | NULL). */ |
| 266 | |
| 267 | void |
| 268 | alpha_find_saved_regs (struct frame_info *frame) |
| 269 | { |
| 270 | int ireg; |
| 271 | CORE_ADDR reg_position; |
| 272 | unsigned long mask; |
| 273 | alpha_extra_func_info_t proc_desc; |
| 274 | int returnreg; |
| 275 | |
| 276 | frame_saved_regs_zalloc (frame); |
| 277 | |
| 278 | /* If it is the frame for __sigtramp, the saved registers are located |
| 279 | in a sigcontext structure somewhere on the stack. __sigtramp |
| 280 | passes a pointer to the sigcontext structure on the stack. |
| 281 | If the stack layout for __sigtramp changes, or if sigcontext offsets |
| 282 | change, we might have to update this code. */ |
| 283 | #ifndef SIGFRAME_PC_OFF |
| 284 | #define SIGFRAME_PC_OFF (2 * 8) |
| 285 | #define SIGFRAME_REGSAVE_OFF (4 * 8) |
| 286 | #define SIGFRAME_FPREGSAVE_OFF (SIGFRAME_REGSAVE_OFF + 32 * 8 + 8) |
| 287 | #endif |
| 288 | if (frame->signal_handler_caller) |
| 289 | { |
| 290 | CORE_ADDR sigcontext_addr; |
| 291 | |
| 292 | sigcontext_addr = SIGCONTEXT_ADDR (frame); |
| 293 | for (ireg = 0; ireg < 32; ireg++) |
| 294 | { |
| 295 | reg_position = sigcontext_addr + SIGFRAME_REGSAVE_OFF + ireg * 8; |
| 296 | frame->saved_regs[ireg] = reg_position; |
| 297 | } |
| 298 | for (ireg = 0; ireg < 32; ireg++) |
| 299 | { |
| 300 | reg_position = sigcontext_addr + SIGFRAME_FPREGSAVE_OFF + ireg * 8; |
| 301 | frame->saved_regs[FP0_REGNUM + ireg] = reg_position; |
| 302 | } |
| 303 | frame->saved_regs[PC_REGNUM] = sigcontext_addr + SIGFRAME_PC_OFF; |
| 304 | return; |
| 305 | } |
| 306 | |
| 307 | proc_desc = frame->proc_desc; |
| 308 | if (proc_desc == NULL) |
| 309 | /* I'm not sure how/whether this can happen. Normally when we can't |
| 310 | find a proc_desc, we "synthesize" one using heuristic_proc_desc |
| 311 | and set the saved_regs right away. */ |
| 312 | return; |
| 313 | |
| 314 | /* Fill in the offsets for the registers which gen_mask says |
| 315 | were saved. */ |
| 316 | |
| 317 | reg_position = frame->frame + PROC_REG_OFFSET (proc_desc); |
| 318 | mask = PROC_REG_MASK (proc_desc); |
| 319 | |
| 320 | returnreg = PROC_PC_REG (proc_desc); |
| 321 | |
| 322 | /* Note that RA is always saved first, regardless of its actual |
| 323 | register number. */ |
| 324 | if (mask & (1 << returnreg)) |
| 325 | { |
| 326 | frame->saved_regs[returnreg] = reg_position; |
| 327 | reg_position += 8; |
| 328 | mask &= ~(1 << returnreg); /* Clear bit for RA so we |
| 329 | don't save again later. */ |
| 330 | } |
| 331 | |
| 332 | for (ireg = 0; ireg <= 31; ++ireg) |
| 333 | if (mask & (1 << ireg)) |
| 334 | { |
| 335 | frame->saved_regs[ireg] = reg_position; |
| 336 | reg_position += 8; |
| 337 | } |
| 338 | |
| 339 | /* Fill in the offsets for the registers which float_mask says |
| 340 | were saved. */ |
| 341 | |
| 342 | reg_position = frame->frame + PROC_FREG_OFFSET (proc_desc); |
| 343 | mask = PROC_FREG_MASK (proc_desc); |
| 344 | |
| 345 | for (ireg = 0; ireg <= 31; ++ireg) |
| 346 | if (mask & (1 << ireg)) |
| 347 | { |
| 348 | frame->saved_regs[FP0_REGNUM + ireg] = reg_position; |
| 349 | reg_position += 8; |
| 350 | } |
| 351 | |
| 352 | frame->saved_regs[PC_REGNUM] = frame->saved_regs[returnreg]; |
| 353 | } |
| 354 | |
| 355 | static CORE_ADDR |
| 356 | read_next_frame_reg (struct frame_info *fi, int regno) |
| 357 | { |
| 358 | for (; fi; fi = fi->next) |
| 359 | { |
| 360 | /* We have to get the saved sp from the sigcontext |
| 361 | if it is a signal handler frame. */ |
| 362 | if (regno == SP_REGNUM && !fi->signal_handler_caller) |
| 363 | return fi->frame; |
| 364 | else |
| 365 | { |
| 366 | if (fi->saved_regs == NULL) |
| 367 | alpha_find_saved_regs (fi); |
| 368 | if (fi->saved_regs[regno]) |
| 369 | return read_memory_integer (fi->saved_regs[regno], 8); |
| 370 | } |
| 371 | } |
| 372 | return read_register (regno); |
| 373 | } |
| 374 | |
| 375 | CORE_ADDR |
| 376 | alpha_frame_saved_pc (struct frame_info *frame) |
| 377 | { |
| 378 | alpha_extra_func_info_t proc_desc = frame->proc_desc; |
| 379 | /* We have to get the saved pc from the sigcontext |
| 380 | if it is a signal handler frame. */ |
| 381 | int pcreg = frame->signal_handler_caller ? PC_REGNUM : frame->pc_reg; |
| 382 | |
| 383 | if (proc_desc && PROC_DESC_IS_DUMMY (proc_desc)) |
| 384 | return read_memory_integer (frame->frame - 8, 8); |
| 385 | |
| 386 | return read_next_frame_reg (frame, pcreg); |
| 387 | } |
| 388 | |
| 389 | CORE_ADDR |
| 390 | alpha_saved_pc_after_call (struct frame_info *frame) |
| 391 | { |
| 392 | CORE_ADDR pc = frame->pc; |
| 393 | CORE_ADDR tmp; |
| 394 | alpha_extra_func_info_t proc_desc; |
| 395 | int pcreg; |
| 396 | |
| 397 | /* Skip over shared library trampoline if necessary. */ |
| 398 | tmp = SKIP_TRAMPOLINE_CODE (pc); |
| 399 | if (tmp != 0) |
| 400 | pc = tmp; |
| 401 | |
| 402 | proc_desc = find_proc_desc (pc, frame->next); |
| 403 | pcreg = proc_desc ? PROC_PC_REG (proc_desc) : RA_REGNUM; |
| 404 | |
| 405 | if (frame->signal_handler_caller) |
| 406 | return alpha_frame_saved_pc (frame); |
| 407 | else |
| 408 | return read_register (pcreg); |
| 409 | } |
| 410 | |
| 411 | |
| 412 | static struct alpha_extra_func_info temp_proc_desc; |
| 413 | static struct frame_saved_regs temp_saved_regs; |
| 414 | |
| 415 | /* Nonzero if instruction at PC is a return instruction. "ret |
| 416 | $zero,($ra),1" on alpha. */ |
| 417 | |
| 418 | static int |
| 419 | alpha_about_to_return (CORE_ADDR pc) |
| 420 | { |
| 421 | return read_memory_integer (pc, 4) == 0x6bfa8001; |
| 422 | } |
| 423 | |
| 424 | |
| 425 | |
| 426 | /* This fencepost looks highly suspicious to me. Removing it also |
| 427 | seems suspicious as it could affect remote debugging across serial |
| 428 | lines. */ |
| 429 | |
| 430 | static CORE_ADDR |
| 431 | heuristic_proc_start (CORE_ADDR pc) |
| 432 | { |
| 433 | CORE_ADDR start_pc = pc; |
| 434 | CORE_ADDR fence = start_pc - heuristic_fence_post; |
| 435 | |
| 436 | if (start_pc == 0) |
| 437 | return 0; |
| 438 | |
| 439 | if (heuristic_fence_post == UINT_MAX |
| 440 | || fence < VM_MIN_ADDRESS) |
| 441 | fence = VM_MIN_ADDRESS; |
| 442 | |
| 443 | /* search back for previous return */ |
| 444 | for (start_pc -= 4;; start_pc -= 4) |
| 445 | if (start_pc < fence) |
| 446 | { |
| 447 | /* It's not clear to me why we reach this point when |
| 448 | stop_soon_quietly, but with this test, at least we |
| 449 | don't print out warnings for every child forked (eg, on |
| 450 | decstation). 22apr93 rich@cygnus.com. */ |
| 451 | if (!stop_soon_quietly) |
| 452 | { |
| 453 | static int blurb_printed = 0; |
| 454 | |
| 455 | if (fence == VM_MIN_ADDRESS) |
| 456 | warning ("Hit beginning of text section without finding"); |
| 457 | else |
| 458 | warning ("Hit heuristic-fence-post without finding"); |
| 459 | |
| 460 | warning ("enclosing function for address 0x%s", paddr_nz (pc)); |
| 461 | if (!blurb_printed) |
| 462 | { |
| 463 | printf_filtered ("\ |
| 464 | This warning occurs if you are debugging a function without any symbols\n\ |
| 465 | (for example, in a stripped executable). In that case, you may wish to\n\ |
| 466 | increase the size of the search with the `set heuristic-fence-post' command.\n\ |
| 467 | \n\ |
| 468 | Otherwise, you told GDB there was a function where there isn't one, or\n\ |
| 469 | (more likely) you have encountered a bug in GDB.\n"); |
| 470 | blurb_printed = 1; |
| 471 | } |
| 472 | } |
| 473 | |
| 474 | return 0; |
| 475 | } |
| 476 | else if (alpha_about_to_return (start_pc)) |
| 477 | break; |
| 478 | |
| 479 | start_pc += 4; /* skip return */ |
| 480 | return start_pc; |
| 481 | } |
| 482 | |
| 483 | static alpha_extra_func_info_t |
| 484 | heuristic_proc_desc (CORE_ADDR start_pc, CORE_ADDR limit_pc, |
| 485 | struct frame_info *next_frame) |
| 486 | { |
| 487 | CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM); |
| 488 | CORE_ADDR cur_pc; |
| 489 | int frame_size; |
| 490 | int has_frame_reg = 0; |
| 491 | unsigned long reg_mask = 0; |
| 492 | int pcreg = -1; |
| 493 | |
| 494 | if (start_pc == 0) |
| 495 | return NULL; |
| 496 | memset (&temp_proc_desc, '\0', sizeof (temp_proc_desc)); |
| 497 | memset (&temp_saved_regs, '\0', sizeof (struct frame_saved_regs)); |
| 498 | PROC_LOW_ADDR (&temp_proc_desc) = start_pc; |
| 499 | |
| 500 | if (start_pc + 200 < limit_pc) |
| 501 | limit_pc = start_pc + 200; |
| 502 | frame_size = 0; |
| 503 | for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4) |
| 504 | { |
| 505 | char buf[4]; |
| 506 | unsigned long word; |
| 507 | int status; |
| 508 | |
| 509 | status = read_memory_nobpt (cur_pc, buf, 4); |
| 510 | if (status) |
| 511 | memory_error (status, cur_pc); |
| 512 | word = extract_unsigned_integer (buf, 4); |
| 513 | |
| 514 | if ((word & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */ |
| 515 | { |
| 516 | if (word & 0x8000) |
| 517 | frame_size += (-word) & 0xffff; |
| 518 | else |
| 519 | /* Exit loop if a positive stack adjustment is found, which |
| 520 | usually means that the stack cleanup code in the function |
| 521 | epilogue is reached. */ |
| 522 | break; |
| 523 | } |
| 524 | else if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */ |
| 525 | && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */ |
| 526 | { |
| 527 | int reg = (word & 0x03e00000) >> 21; |
| 528 | reg_mask |= 1 << reg; |
| 529 | temp_saved_regs.regs[reg] = sp + (short) word; |
| 530 | |
| 531 | /* Starting with OSF/1-3.2C, the system libraries are shipped |
| 532 | without local symbols, but they still contain procedure |
| 533 | descriptors without a symbol reference. GDB is currently |
| 534 | unable to find these procedure descriptors and uses |
| 535 | heuristic_proc_desc instead. |
| 536 | As some low level compiler support routines (__div*, __add*) |
| 537 | use a non-standard return address register, we have to |
| 538 | add some heuristics to determine the return address register, |
| 539 | or stepping over these routines will fail. |
| 540 | Usually the return address register is the first register |
| 541 | saved on the stack, but assembler optimization might |
| 542 | rearrange the register saves. |
| 543 | So we recognize only a few registers (t7, t9, ra) within |
| 544 | the procedure prologue as valid return address registers. |
| 545 | If we encounter a return instruction, we extract the |
| 546 | the return address register from it. |
| 547 | |
| 548 | FIXME: Rewriting GDB to access the procedure descriptors, |
| 549 | e.g. via the minimal symbol table, might obviate this hack. */ |
| 550 | if (pcreg == -1 |
| 551 | && cur_pc < (start_pc + 80) |
| 552 | && (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM)) |
| 553 | pcreg = reg; |
| 554 | } |
| 555 | else if ((word & 0xffe0ffff) == 0x6be08001) /* ret zero,reg,1 */ |
| 556 | pcreg = (word >> 16) & 0x1f; |
| 557 | else if (word == 0x47de040f) /* bis sp,sp fp */ |
| 558 | has_frame_reg = 1; |
| 559 | } |
| 560 | if (pcreg == -1) |
| 561 | { |
| 562 | /* If we haven't found a valid return address register yet, |
| 563 | keep searching in the procedure prologue. */ |
| 564 | while (cur_pc < (limit_pc + 80) && cur_pc < (start_pc + 80)) |
| 565 | { |
| 566 | char buf[4]; |
| 567 | unsigned long word; |
| 568 | |
| 569 | if (read_memory_nobpt (cur_pc, buf, 4)) |
| 570 | break; |
| 571 | cur_pc += 4; |
| 572 | word = extract_unsigned_integer (buf, 4); |
| 573 | |
| 574 | if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */ |
| 575 | && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */ |
| 576 | { |
| 577 | int reg = (word & 0x03e00000) >> 21; |
| 578 | if (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM) |
| 579 | { |
| 580 | pcreg = reg; |
| 581 | break; |
| 582 | } |
| 583 | } |
| 584 | else if ((word & 0xffe0ffff) == 0x6be08001) /* ret zero,reg,1 */ |
| 585 | { |
| 586 | pcreg = (word >> 16) & 0x1f; |
| 587 | break; |
| 588 | } |
| 589 | } |
| 590 | } |
| 591 | |
| 592 | if (has_frame_reg) |
| 593 | PROC_FRAME_REG (&temp_proc_desc) = GCC_FP_REGNUM; |
| 594 | else |
| 595 | PROC_FRAME_REG (&temp_proc_desc) = SP_REGNUM; |
| 596 | PROC_FRAME_OFFSET (&temp_proc_desc) = frame_size; |
| 597 | PROC_REG_MASK (&temp_proc_desc) = reg_mask; |
| 598 | PROC_PC_REG (&temp_proc_desc) = (pcreg == -1) ? RA_REGNUM : pcreg; |
| 599 | PROC_LOCALOFF (&temp_proc_desc) = 0; /* XXX - bogus */ |
| 600 | return &temp_proc_desc; |
| 601 | } |
| 602 | |
| 603 | /* This returns the PC of the first inst after the prologue. If we can't |
| 604 | find the prologue, then return 0. */ |
| 605 | |
| 606 | static CORE_ADDR |
| 607 | after_prologue (CORE_ADDR pc, alpha_extra_func_info_t proc_desc) |
| 608 | { |
| 609 | struct symtab_and_line sal; |
| 610 | CORE_ADDR func_addr, func_end; |
| 611 | |
| 612 | if (!proc_desc) |
| 613 | proc_desc = find_proc_desc (pc, NULL); |
| 614 | |
| 615 | if (proc_desc) |
| 616 | { |
| 617 | if (PROC_DESC_IS_DYN_SIGTRAMP (proc_desc)) |
| 618 | return PROC_LOW_ADDR (proc_desc); /* "prologue" is in kernel */ |
| 619 | |
| 620 | /* If function is frameless, then we need to do it the hard way. I |
| 621 | strongly suspect that frameless always means prologueless... */ |
| 622 | if (PROC_FRAME_REG (proc_desc) == SP_REGNUM |
| 623 | && PROC_FRAME_OFFSET (proc_desc) == 0) |
| 624 | return 0; |
| 625 | } |
| 626 | |
| 627 | if (!find_pc_partial_function (pc, NULL, &func_addr, &func_end)) |
| 628 | return 0; /* Unknown */ |
| 629 | |
| 630 | sal = find_pc_line (func_addr, 0); |
| 631 | |
| 632 | if (sal.end < func_end) |
| 633 | return sal.end; |
| 634 | |
| 635 | /* The line after the prologue is after the end of the function. In this |
| 636 | case, tell the caller to find the prologue the hard way. */ |
| 637 | |
| 638 | return 0; |
| 639 | } |
| 640 | |
| 641 | /* Return non-zero if we *might* be in a function prologue. Return zero if we |
| 642 | are definitively *not* in a function prologue. */ |
| 643 | |
| 644 | static int |
| 645 | alpha_in_prologue (CORE_ADDR pc, alpha_extra_func_info_t proc_desc) |
| 646 | { |
| 647 | CORE_ADDR after_prologue_pc; |
| 648 | |
| 649 | after_prologue_pc = after_prologue (pc, proc_desc); |
| 650 | |
| 651 | if (after_prologue_pc == 0 |
| 652 | || pc < after_prologue_pc) |
| 653 | return 1; |
| 654 | else |
| 655 | return 0; |
| 656 | } |
| 657 | |
| 658 | static alpha_extra_func_info_t |
| 659 | find_proc_desc (CORE_ADDR pc, struct frame_info *next_frame) |
| 660 | { |
| 661 | alpha_extra_func_info_t proc_desc; |
| 662 | struct block *b; |
| 663 | struct symbol *sym; |
| 664 | CORE_ADDR startaddr; |
| 665 | |
| 666 | /* Try to get the proc_desc from the linked call dummy proc_descs |
| 667 | if the pc is in the call dummy. |
| 668 | This is hairy. In the case of nested dummy calls we have to find the |
| 669 | right proc_desc, but we might not yet know the frame for the dummy |
| 670 | as it will be contained in the proc_desc we are searching for. |
| 671 | So we have to find the proc_desc whose frame is closest to the current |
| 672 | stack pointer. */ |
| 673 | |
| 674 | if (PC_IN_CALL_DUMMY (pc, 0, 0)) |
| 675 | { |
| 676 | struct linked_proc_info *link; |
| 677 | CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM); |
| 678 | alpha_extra_func_info_t found_proc_desc = NULL; |
| 679 | long min_distance = LONG_MAX; |
| 680 | |
| 681 | for (link = linked_proc_desc_table; link; link = link->next) |
| 682 | { |
| 683 | long distance = (CORE_ADDR) PROC_DUMMY_FRAME (&link->info) - sp; |
| 684 | if (distance > 0 && distance < min_distance) |
| 685 | { |
| 686 | min_distance = distance; |
| 687 | found_proc_desc = &link->info; |
| 688 | } |
| 689 | } |
| 690 | if (found_proc_desc != NULL) |
| 691 | return found_proc_desc; |
| 692 | } |
| 693 | |
| 694 | b = block_for_pc (pc); |
| 695 | |
| 696 | find_pc_partial_function (pc, NULL, &startaddr, NULL); |
| 697 | if (b == NULL) |
| 698 | sym = NULL; |
| 699 | else |
| 700 | { |
| 701 | if (startaddr > BLOCK_START (b)) |
| 702 | /* This is the "pathological" case referred to in a comment in |
| 703 | print_frame_info. It might be better to move this check into |
| 704 | symbol reading. */ |
| 705 | sym = NULL; |
| 706 | else |
| 707 | sym = lookup_symbol (MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE, |
| 708 | 0, NULL); |
| 709 | } |
| 710 | |
| 711 | /* If we never found a PDR for this function in symbol reading, then |
| 712 | examine prologues to find the information. */ |
| 713 | if (sym && ((mips_extra_func_info_t) SYMBOL_VALUE (sym))->pdr.framereg == -1) |
| 714 | sym = NULL; |
| 715 | |
| 716 | if (sym) |
| 717 | { |
| 718 | /* IF this is the topmost frame AND |
| 719 | * (this proc does not have debugging information OR |
| 720 | * the PC is in the procedure prologue) |
| 721 | * THEN create a "heuristic" proc_desc (by analyzing |
| 722 | * the actual code) to replace the "official" proc_desc. |
| 723 | */ |
| 724 | proc_desc = (alpha_extra_func_info_t) SYMBOL_VALUE (sym); |
| 725 | if (next_frame == NULL) |
| 726 | { |
| 727 | if (PROC_DESC_IS_DUMMY (proc_desc) || alpha_in_prologue (pc, proc_desc)) |
| 728 | { |
| 729 | alpha_extra_func_info_t found_heuristic = |
| 730 | heuristic_proc_desc (PROC_LOW_ADDR (proc_desc), |
| 731 | pc, next_frame); |
| 732 | if (found_heuristic) |
| 733 | { |
| 734 | PROC_LOCALOFF (found_heuristic) = |
| 735 | PROC_LOCALOFF (proc_desc); |
| 736 | PROC_PC_REG (found_heuristic) = PROC_PC_REG (proc_desc); |
| 737 | proc_desc = found_heuristic; |
| 738 | } |
| 739 | } |
| 740 | } |
| 741 | } |
| 742 | else |
| 743 | { |
| 744 | long offset; |
| 745 | |
| 746 | /* Is linked_proc_desc_table really necessary? It only seems to be used |
| 747 | by procedure call dummys. However, the procedures being called ought |
| 748 | to have their own proc_descs, and even if they don't, |
| 749 | heuristic_proc_desc knows how to create them! */ |
| 750 | |
| 751 | register struct linked_proc_info *link; |
| 752 | for (link = linked_proc_desc_table; link; link = link->next) |
| 753 | if (PROC_LOW_ADDR (&link->info) <= pc |
| 754 | && PROC_HIGH_ADDR (&link->info) > pc) |
| 755 | return &link->info; |
| 756 | |
| 757 | /* If PC is inside a dynamically generated sigtramp handler, |
| 758 | create and push a procedure descriptor for that code: */ |
| 759 | offset = DYNAMIC_SIGTRAMP_OFFSET (pc); |
| 760 | if (offset >= 0) |
| 761 | return push_sigtramp_desc (pc - offset); |
| 762 | |
| 763 | /* If heuristic_fence_post is non-zero, determine the procedure |
| 764 | start address by examining the instructions. |
| 765 | This allows us to find the start address of static functions which |
| 766 | have no symbolic information, as startaddr would have been set to |
| 767 | the preceding global function start address by the |
| 768 | find_pc_partial_function call above. */ |
| 769 | if (startaddr == 0 || heuristic_fence_post != 0) |
| 770 | startaddr = heuristic_proc_start (pc); |
| 771 | |
| 772 | proc_desc = |
| 773 | heuristic_proc_desc (startaddr, pc, next_frame); |
| 774 | } |
| 775 | return proc_desc; |
| 776 | } |
| 777 | |
| 778 | alpha_extra_func_info_t cached_proc_desc; |
| 779 | |
| 780 | CORE_ADDR |
| 781 | alpha_frame_chain (struct frame_info *frame) |
| 782 | { |
| 783 | alpha_extra_func_info_t proc_desc; |
| 784 | CORE_ADDR saved_pc = FRAME_SAVED_PC (frame); |
| 785 | |
| 786 | if (saved_pc == 0 || inside_entry_file (saved_pc)) |
| 787 | return 0; |
| 788 | |
| 789 | proc_desc = find_proc_desc (saved_pc, frame); |
| 790 | if (!proc_desc) |
| 791 | return 0; |
| 792 | |
| 793 | cached_proc_desc = proc_desc; |
| 794 | |
| 795 | /* Fetch the frame pointer for a dummy frame from the procedure |
| 796 | descriptor. */ |
| 797 | if (PROC_DESC_IS_DUMMY (proc_desc)) |
| 798 | return (CORE_ADDR) PROC_DUMMY_FRAME (proc_desc); |
| 799 | |
| 800 | /* If no frame pointer and frame size is zero, we must be at end |
| 801 | of stack (or otherwise hosed). If we don't check frame size, |
| 802 | we loop forever if we see a zero size frame. */ |
| 803 | if (PROC_FRAME_REG (proc_desc) == SP_REGNUM |
| 804 | && PROC_FRAME_OFFSET (proc_desc) == 0 |
| 805 | /* The previous frame from a sigtramp frame might be frameless |
| 806 | and have frame size zero. */ |
| 807 | && !frame->signal_handler_caller) |
| 808 | return FRAME_PAST_SIGTRAMP_FRAME (frame, saved_pc); |
| 809 | else |
| 810 | return read_next_frame_reg (frame, PROC_FRAME_REG (proc_desc)) |
| 811 | + PROC_FRAME_OFFSET (proc_desc); |
| 812 | } |
| 813 | |
| 814 | void |
| 815 | init_extra_frame_info (struct frame_info *frame) |
| 816 | { |
| 817 | /* Use proc_desc calculated in frame_chain */ |
| 818 | alpha_extra_func_info_t proc_desc = |
| 819 | frame->next ? cached_proc_desc : find_proc_desc (frame->pc, frame->next); |
| 820 | |
| 821 | frame->saved_regs = NULL; |
| 822 | frame->localoff = 0; |
| 823 | frame->pc_reg = RA_REGNUM; |
| 824 | frame->proc_desc = proc_desc == &temp_proc_desc ? 0 : proc_desc; |
| 825 | if (proc_desc) |
| 826 | { |
| 827 | /* Get the locals offset and the saved pc register from the |
| 828 | procedure descriptor, they are valid even if we are in the |
| 829 | middle of the prologue. */ |
| 830 | frame->localoff = PROC_LOCALOFF (proc_desc); |
| 831 | frame->pc_reg = PROC_PC_REG (proc_desc); |
| 832 | |
| 833 | /* Fixup frame-pointer - only needed for top frame */ |
| 834 | |
| 835 | /* Fetch the frame pointer for a dummy frame from the procedure |
| 836 | descriptor. */ |
| 837 | if (PROC_DESC_IS_DUMMY (proc_desc)) |
| 838 | frame->frame = (CORE_ADDR) PROC_DUMMY_FRAME (proc_desc); |
| 839 | |
| 840 | /* This may not be quite right, if proc has a real frame register. |
| 841 | Get the value of the frame relative sp, procedure might have been |
| 842 | interrupted by a signal at it's very start. */ |
| 843 | else if (frame->pc == PROC_LOW_ADDR (proc_desc) |
| 844 | && !PROC_DESC_IS_DYN_SIGTRAMP (proc_desc)) |
| 845 | frame->frame = read_next_frame_reg (frame->next, SP_REGNUM); |
| 846 | else |
| 847 | frame->frame = read_next_frame_reg (frame->next, PROC_FRAME_REG (proc_desc)) |
| 848 | + PROC_FRAME_OFFSET (proc_desc); |
| 849 | |
| 850 | if (proc_desc == &temp_proc_desc) |
| 851 | { |
| 852 | char *name; |
| 853 | |
| 854 | /* Do not set the saved registers for a sigtramp frame, |
| 855 | alpha_find_saved_registers will do that for us. |
| 856 | We can't use frame->signal_handler_caller, it is not yet set. */ |
| 857 | find_pc_partial_function (frame->pc, &name, |
| 858 | (CORE_ADDR *) NULL, (CORE_ADDR *) NULL); |
| 859 | if (!IN_SIGTRAMP (frame->pc, name)) |
| 860 | { |
| 861 | frame->saved_regs = (CORE_ADDR *) |
| 862 | frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS); |
| 863 | memcpy (frame->saved_regs, temp_saved_regs.regs, SIZEOF_FRAME_SAVED_REGS); |
| 864 | frame->saved_regs[PC_REGNUM] |
| 865 | = frame->saved_regs[RA_REGNUM]; |
| 866 | } |
| 867 | } |
| 868 | } |
| 869 | } |
| 870 | |
| 871 | /* ALPHA stack frames are almost impenetrable. When execution stops, |
| 872 | we basically have to look at symbol information for the function |
| 873 | that we stopped in, which tells us *which* register (if any) is |
| 874 | the base of the frame pointer, and what offset from that register |
| 875 | the frame itself is at. |
| 876 | |
| 877 | This presents a problem when trying to examine a stack in memory |
| 878 | (that isn't executing at the moment), using the "frame" command. We |
| 879 | don't have a PC, nor do we have any registers except SP. |
| 880 | |
| 881 | This routine takes two arguments, SP and PC, and tries to make the |
| 882 | cached frames look as if these two arguments defined a frame on the |
| 883 | cache. This allows the rest of info frame to extract the important |
| 884 | arguments without difficulty. */ |
| 885 | |
| 886 | struct frame_info * |
| 887 | setup_arbitrary_frame (int argc, CORE_ADDR *argv) |
| 888 | { |
| 889 | if (argc != 2) |
| 890 | error ("ALPHA frame specifications require two arguments: sp and pc"); |
| 891 | |
| 892 | return create_new_frame (argv[0], argv[1]); |
| 893 | } |
| 894 | |
| 895 | /* The alpha passes the first six arguments in the registers, the rest on |
| 896 | the stack. The register arguments are eventually transferred to the |
| 897 | argument transfer area immediately below the stack by the called function |
| 898 | anyway. So we `push' at least six arguments on the stack, `reload' the |
| 899 | argument registers and then adjust the stack pointer to point past the |
| 900 | sixth argument. This algorithm simplifies the passing of a large struct |
| 901 | which extends from the registers to the stack. |
| 902 | If the called function is returning a structure, the address of the |
| 903 | structure to be returned is passed as a hidden first argument. */ |
| 904 | |
| 905 | CORE_ADDR |
| 906 | alpha_push_arguments (int nargs, struct value **args, CORE_ADDR sp, |
| 907 | int struct_return, CORE_ADDR struct_addr) |
| 908 | { |
| 909 | int i; |
| 910 | int accumulate_size = struct_return ? 8 : 0; |
| 911 | int arg_regs_size = ALPHA_NUM_ARG_REGS * 8; |
| 912 | struct alpha_arg |
| 913 | { |
| 914 | char *contents; |
| 915 | int len; |
| 916 | int offset; |
| 917 | }; |
| 918 | struct alpha_arg *alpha_args = |
| 919 | (struct alpha_arg *) alloca (nargs * sizeof (struct alpha_arg)); |
| 920 | register struct alpha_arg *m_arg; |
| 921 | char raw_buffer[sizeof (CORE_ADDR)]; |
| 922 | int required_arg_regs; |
| 923 | |
| 924 | for (i = 0, m_arg = alpha_args; i < nargs; i++, m_arg++) |
| 925 | { |
| 926 | struct value *arg = args[i]; |
| 927 | struct type *arg_type = check_typedef (VALUE_TYPE (arg)); |
| 928 | /* Cast argument to long if necessary as the compiler does it too. */ |
| 929 | switch (TYPE_CODE (arg_type)) |
| 930 | { |
| 931 | case TYPE_CODE_INT: |
| 932 | case TYPE_CODE_BOOL: |
| 933 | case TYPE_CODE_CHAR: |
| 934 | case TYPE_CODE_RANGE: |
| 935 | case TYPE_CODE_ENUM: |
| 936 | if (TYPE_LENGTH (arg_type) < TYPE_LENGTH (builtin_type_long)) |
| 937 | { |
| 938 | arg_type = builtin_type_long; |
| 939 | arg = value_cast (arg_type, arg); |
| 940 | } |
| 941 | break; |
| 942 | default: |
| 943 | break; |
| 944 | } |
| 945 | m_arg->len = TYPE_LENGTH (arg_type); |
| 946 | m_arg->offset = accumulate_size; |
| 947 | accumulate_size = (accumulate_size + m_arg->len + 7) & ~7; |
| 948 | m_arg->contents = VALUE_CONTENTS (arg); |
| 949 | } |
| 950 | |
| 951 | /* Determine required argument register loads, loading an argument register |
| 952 | is expensive as it uses three ptrace calls. */ |
| 953 | required_arg_regs = accumulate_size / 8; |
| 954 | if (required_arg_regs > ALPHA_NUM_ARG_REGS) |
| 955 | required_arg_regs = ALPHA_NUM_ARG_REGS; |
| 956 | |
| 957 | /* Make room for the arguments on the stack. */ |
| 958 | if (accumulate_size < arg_regs_size) |
| 959 | accumulate_size = arg_regs_size; |
| 960 | sp -= accumulate_size; |
| 961 | |
| 962 | /* Keep sp aligned to a multiple of 16 as the compiler does it too. */ |
| 963 | sp &= ~15; |
| 964 | |
| 965 | /* `Push' arguments on the stack. */ |
| 966 | for (i = nargs; m_arg--, --i >= 0;) |
| 967 | write_memory (sp + m_arg->offset, m_arg->contents, m_arg->len); |
| 968 | if (struct_return) |
| 969 | { |
| 970 | store_address (raw_buffer, sizeof (CORE_ADDR), struct_addr); |
| 971 | write_memory (sp, raw_buffer, sizeof (CORE_ADDR)); |
| 972 | } |
| 973 | |
| 974 | /* Load the argument registers. */ |
| 975 | for (i = 0; i < required_arg_regs; i++) |
| 976 | { |
| 977 | LONGEST val; |
| 978 | |
| 979 | val = read_memory_integer (sp + i * 8, 8); |
| 980 | write_register (A0_REGNUM + i, val); |
| 981 | write_register (FPA0_REGNUM + i, val); |
| 982 | } |
| 983 | |
| 984 | return sp + arg_regs_size; |
| 985 | } |
| 986 | |
| 987 | void |
| 988 | alpha_push_dummy_frame (void) |
| 989 | { |
| 990 | int ireg; |
| 991 | struct linked_proc_info *link; |
| 992 | alpha_extra_func_info_t proc_desc; |
| 993 | CORE_ADDR sp = read_register (SP_REGNUM); |
| 994 | CORE_ADDR save_address; |
| 995 | char raw_buffer[MAX_REGISTER_RAW_SIZE]; |
| 996 | unsigned long mask; |
| 997 | |
| 998 | link = (struct linked_proc_info *) xmalloc (sizeof (struct linked_proc_info)); |
| 999 | link->next = linked_proc_desc_table; |
| 1000 | linked_proc_desc_table = link; |
| 1001 | |
| 1002 | proc_desc = &link->info; |
| 1003 | |
| 1004 | /* |
| 1005 | * The registers we must save are all those not preserved across |
| 1006 | * procedure calls. |
| 1007 | * In addition, we must save the PC and RA. |
| 1008 | * |
| 1009 | * Dummy frame layout: |
| 1010 | * (high memory) |
| 1011 | * Saved PC |
| 1012 | * Saved F30 |
| 1013 | * ... |
| 1014 | * Saved F0 |
| 1015 | * Saved R29 |
| 1016 | * ... |
| 1017 | * Saved R0 |
| 1018 | * Saved R26 (RA) |
| 1019 | * Parameter build area |
| 1020 | * (low memory) |
| 1021 | */ |
| 1022 | |
| 1023 | /* MASK(i,j) == (1<<i) + (1<<(i+1)) + ... + (1<<j)). Assume i<=j<31. */ |
| 1024 | #define MASK(i,j) ((((LONGEST)1 << ((j)+1)) - 1) ^ (((LONGEST)1 << (i)) - 1)) |
| 1025 | #define GEN_REG_SAVE_MASK (MASK(0,8) | MASK(16,29)) |
| 1026 | #define GEN_REG_SAVE_COUNT 24 |
| 1027 | #define FLOAT_REG_SAVE_MASK (MASK(0,1) | MASK(10,30)) |
| 1028 | #define FLOAT_REG_SAVE_COUNT 23 |
| 1029 | /* The special register is the PC as we have no bit for it in the save masks. |
| 1030 | alpha_frame_saved_pc knows where the pc is saved in a dummy frame. */ |
| 1031 | #define SPECIAL_REG_SAVE_COUNT 1 |
| 1032 | |
| 1033 | PROC_REG_MASK (proc_desc) = GEN_REG_SAVE_MASK; |
| 1034 | PROC_FREG_MASK (proc_desc) = FLOAT_REG_SAVE_MASK; |
| 1035 | /* PROC_REG_OFFSET is the offset from the dummy frame to the saved RA, |
| 1036 | but keep SP aligned to a multiple of 16. */ |
| 1037 | PROC_REG_OFFSET (proc_desc) = |
| 1038 | -((8 * (SPECIAL_REG_SAVE_COUNT |
| 1039 | + GEN_REG_SAVE_COUNT |
| 1040 | + FLOAT_REG_SAVE_COUNT) |
| 1041 | + 15) & ~15); |
| 1042 | PROC_FREG_OFFSET (proc_desc) = |
| 1043 | PROC_REG_OFFSET (proc_desc) + 8 * GEN_REG_SAVE_COUNT; |
| 1044 | |
| 1045 | /* Save general registers. |
| 1046 | The return address register is the first saved register, all other |
| 1047 | registers follow in ascending order. |
| 1048 | The PC is saved immediately below the SP. */ |
| 1049 | save_address = sp + PROC_REG_OFFSET (proc_desc); |
| 1050 | store_address (raw_buffer, 8, read_register (RA_REGNUM)); |
| 1051 | write_memory (save_address, raw_buffer, 8); |
| 1052 | save_address += 8; |
| 1053 | mask = PROC_REG_MASK (proc_desc) & 0xffffffffL; |
| 1054 | for (ireg = 0; mask; ireg++, mask >>= 1) |
| 1055 | if (mask & 1) |
| 1056 | { |
| 1057 | if (ireg == RA_REGNUM) |
| 1058 | continue; |
| 1059 | store_address (raw_buffer, 8, read_register (ireg)); |
| 1060 | write_memory (save_address, raw_buffer, 8); |
| 1061 | save_address += 8; |
| 1062 | } |
| 1063 | |
| 1064 | store_address (raw_buffer, 8, read_register (PC_REGNUM)); |
| 1065 | write_memory (sp - 8, raw_buffer, 8); |
| 1066 | |
| 1067 | /* Save floating point registers. */ |
| 1068 | save_address = sp + PROC_FREG_OFFSET (proc_desc); |
| 1069 | mask = PROC_FREG_MASK (proc_desc) & 0xffffffffL; |
| 1070 | for (ireg = 0; mask; ireg++, mask >>= 1) |
| 1071 | if (mask & 1) |
| 1072 | { |
| 1073 | store_address (raw_buffer, 8, read_register (ireg + FP0_REGNUM)); |
| 1074 | write_memory (save_address, raw_buffer, 8); |
| 1075 | save_address += 8; |
| 1076 | } |
| 1077 | |
| 1078 | /* Set and save the frame address for the dummy. |
| 1079 | This is tricky. The only registers that are suitable for a frame save |
| 1080 | are those that are preserved across procedure calls (s0-s6). But if |
| 1081 | a read system call is interrupted and then a dummy call is made |
| 1082 | (see testsuite/gdb.t17/interrupt.exp) the dummy call hangs till the read |
| 1083 | is satisfied. Then it returns with the s0-s6 registers set to the values |
| 1084 | on entry to the read system call and our dummy frame pointer would be |
| 1085 | destroyed. So we save the dummy frame in the proc_desc and handle the |
| 1086 | retrieval of the frame pointer of a dummy specifically. The frame register |
| 1087 | is set to the virtual frame (pseudo) register, it's value will always |
| 1088 | be read as zero and will help us to catch any errors in the dummy frame |
| 1089 | retrieval code. */ |
| 1090 | PROC_DUMMY_FRAME (proc_desc) = sp; |
| 1091 | PROC_FRAME_REG (proc_desc) = FP_REGNUM; |
| 1092 | PROC_FRAME_OFFSET (proc_desc) = 0; |
| 1093 | sp += PROC_REG_OFFSET (proc_desc); |
| 1094 | write_register (SP_REGNUM, sp); |
| 1095 | |
| 1096 | PROC_LOW_ADDR (proc_desc) = CALL_DUMMY_ADDRESS (); |
| 1097 | PROC_HIGH_ADDR (proc_desc) = PROC_LOW_ADDR (proc_desc) + 4; |
| 1098 | |
| 1099 | SET_PROC_DESC_IS_DUMMY (proc_desc); |
| 1100 | PROC_PC_REG (proc_desc) = RA_REGNUM; |
| 1101 | } |
| 1102 | |
| 1103 | void |
| 1104 | alpha_pop_frame (void) |
| 1105 | { |
| 1106 | register int regnum; |
| 1107 | struct frame_info *frame = get_current_frame (); |
| 1108 | CORE_ADDR new_sp = frame->frame; |
| 1109 | |
| 1110 | alpha_extra_func_info_t proc_desc = frame->proc_desc; |
| 1111 | |
| 1112 | /* we need proc_desc to know how to restore the registers; |
| 1113 | if it is NULL, construct (a temporary) one */ |
| 1114 | if (proc_desc == NULL) |
| 1115 | proc_desc = find_proc_desc (frame->pc, frame->next); |
| 1116 | |
| 1117 | /* Question: should we copy this proc_desc and save it in |
| 1118 | frame->proc_desc? If we do, who will free it? |
| 1119 | For now, we don't save a copy... */ |
| 1120 | |
| 1121 | write_register (PC_REGNUM, FRAME_SAVED_PC (frame)); |
| 1122 | if (frame->saved_regs == NULL) |
| 1123 | alpha_find_saved_regs (frame); |
| 1124 | if (proc_desc) |
| 1125 | { |
| 1126 | for (regnum = 32; --regnum >= 0;) |
| 1127 | if (PROC_REG_MASK (proc_desc) & (1 << regnum)) |
| 1128 | write_register (regnum, |
| 1129 | read_memory_integer (frame->saved_regs[regnum], |
| 1130 | 8)); |
| 1131 | for (regnum = 32; --regnum >= 0;) |
| 1132 | if (PROC_FREG_MASK (proc_desc) & (1 << regnum)) |
| 1133 | write_register (regnum + FP0_REGNUM, |
| 1134 | read_memory_integer (frame->saved_regs[regnum + FP0_REGNUM], 8)); |
| 1135 | } |
| 1136 | write_register (SP_REGNUM, new_sp); |
| 1137 | flush_cached_frames (); |
| 1138 | |
| 1139 | if (proc_desc && (PROC_DESC_IS_DUMMY (proc_desc) |
| 1140 | || PROC_DESC_IS_DYN_SIGTRAMP (proc_desc))) |
| 1141 | { |
| 1142 | struct linked_proc_info *pi_ptr, *prev_ptr; |
| 1143 | |
| 1144 | for (pi_ptr = linked_proc_desc_table, prev_ptr = NULL; |
| 1145 | pi_ptr != NULL; |
| 1146 | prev_ptr = pi_ptr, pi_ptr = pi_ptr->next) |
| 1147 | { |
| 1148 | if (&pi_ptr->info == proc_desc) |
| 1149 | break; |
| 1150 | } |
| 1151 | |
| 1152 | if (pi_ptr == NULL) |
| 1153 | error ("Can't locate dummy extra frame info\n"); |
| 1154 | |
| 1155 | if (prev_ptr != NULL) |
| 1156 | prev_ptr->next = pi_ptr->next; |
| 1157 | else |
| 1158 | linked_proc_desc_table = pi_ptr->next; |
| 1159 | |
| 1160 | xfree (pi_ptr); |
| 1161 | } |
| 1162 | } |
| 1163 | \f |
| 1164 | /* To skip prologues, I use this predicate. Returns either PC itself |
| 1165 | if the code at PC does not look like a function prologue; otherwise |
| 1166 | returns an address that (if we're lucky) follows the prologue. If |
| 1167 | LENIENT, then we must skip everything which is involved in setting |
| 1168 | up the frame (it's OK to skip more, just so long as we don't skip |
| 1169 | anything which might clobber the registers which are being saved. |
| 1170 | Currently we must not skip more on the alpha, but we might need the |
| 1171 | lenient stuff some day. */ |
| 1172 | |
| 1173 | CORE_ADDR |
| 1174 | alpha_skip_prologue (CORE_ADDR pc, int lenient) |
| 1175 | { |
| 1176 | unsigned long inst; |
| 1177 | int offset; |
| 1178 | CORE_ADDR post_prologue_pc; |
| 1179 | char buf[4]; |
| 1180 | |
| 1181 | #ifdef GDB_TARGET_HAS_SHARED_LIBS |
| 1182 | /* Silently return the unaltered pc upon memory errors. |
| 1183 | This could happen on OSF/1 if decode_line_1 tries to skip the |
| 1184 | prologue for quickstarted shared library functions when the |
| 1185 | shared library is not yet mapped in. |
| 1186 | Reading target memory is slow over serial lines, so we perform |
| 1187 | this check only if the target has shared libraries. */ |
| 1188 | if (target_read_memory (pc, buf, 4)) |
| 1189 | return pc; |
| 1190 | #endif |
| 1191 | |
| 1192 | /* See if we can determine the end of the prologue via the symbol table. |
| 1193 | If so, then return either PC, or the PC after the prologue, whichever |
| 1194 | is greater. */ |
| 1195 | |
| 1196 | post_prologue_pc = after_prologue (pc, NULL); |
| 1197 | |
| 1198 | if (post_prologue_pc != 0) |
| 1199 | return max (pc, post_prologue_pc); |
| 1200 | |
| 1201 | /* Can't determine prologue from the symbol table, need to examine |
| 1202 | instructions. */ |
| 1203 | |
| 1204 | /* Skip the typical prologue instructions. These are the stack adjustment |
| 1205 | instruction and the instructions that save registers on the stack |
| 1206 | or in the gcc frame. */ |
| 1207 | for (offset = 0; offset < 100; offset += 4) |
| 1208 | { |
| 1209 | int status; |
| 1210 | |
| 1211 | status = read_memory_nobpt (pc + offset, buf, 4); |
| 1212 | if (status) |
| 1213 | memory_error (status, pc + offset); |
| 1214 | inst = extract_unsigned_integer (buf, 4); |
| 1215 | |
| 1216 | /* The alpha has no delay slots. But let's keep the lenient stuff, |
| 1217 | we might need it for something else in the future. */ |
| 1218 | if (lenient && 0) |
| 1219 | continue; |
| 1220 | |
| 1221 | if ((inst & 0xffff0000) == 0x27bb0000) /* ldah $gp,n($t12) */ |
| 1222 | continue; |
| 1223 | if ((inst & 0xffff0000) == 0x23bd0000) /* lda $gp,n($gp) */ |
| 1224 | continue; |
| 1225 | if ((inst & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */ |
| 1226 | continue; |
| 1227 | if ((inst & 0xffe01fff) == 0x43c0153e) /* subq $sp,n,$sp */ |
| 1228 | continue; |
| 1229 | |
| 1230 | if ((inst & 0xfc1f0000) == 0xb41e0000 |
| 1231 | && (inst & 0xffff0000) != 0xb7fe0000) |
| 1232 | continue; /* stq reg,n($sp) */ |
| 1233 | /* reg != $zero */ |
| 1234 | if ((inst & 0xfc1f0000) == 0x9c1e0000 |
| 1235 | && (inst & 0xffff0000) != 0x9ffe0000) |
| 1236 | continue; /* stt reg,n($sp) */ |
| 1237 | /* reg != $zero */ |
| 1238 | if (inst == 0x47de040f) /* bis sp,sp,fp */ |
| 1239 | continue; |
| 1240 | |
| 1241 | break; |
| 1242 | } |
| 1243 | return pc + offset; |
| 1244 | } |
| 1245 | |
| 1246 | #if 0 |
| 1247 | /* Is address PC in the prologue (loosely defined) for function at |
| 1248 | STARTADDR? */ |
| 1249 | |
| 1250 | static int |
| 1251 | alpha_in_lenient_prologue (CORE_ADDR startaddr, CORE_ADDR pc) |
| 1252 | { |
| 1253 | CORE_ADDR end_prologue = alpha_skip_prologue (startaddr, 1); |
| 1254 | return pc >= startaddr && pc < end_prologue; |
| 1255 | } |
| 1256 | #endif |
| 1257 | |
| 1258 | /* The alpha needs a conversion between register and memory format if |
| 1259 | the register is a floating point register and |
| 1260 | memory format is float, as the register format must be double |
| 1261 | or |
| 1262 | memory format is an integer with 4 bytes or less, as the representation |
| 1263 | of integers in floating point registers is different. */ |
| 1264 | void |
| 1265 | alpha_register_convert_to_virtual (int regnum, struct type *valtype, |
| 1266 | char *raw_buffer, char *virtual_buffer) |
| 1267 | { |
| 1268 | if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum)) |
| 1269 | { |
| 1270 | memcpy (virtual_buffer, raw_buffer, REGISTER_VIRTUAL_SIZE (regnum)); |
| 1271 | return; |
| 1272 | } |
| 1273 | |
| 1274 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) |
| 1275 | { |
| 1276 | double d = extract_floating (raw_buffer, REGISTER_RAW_SIZE (regnum)); |
| 1277 | store_floating (virtual_buffer, TYPE_LENGTH (valtype), d); |
| 1278 | } |
| 1279 | else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4) |
| 1280 | { |
| 1281 | ULONGEST l; |
| 1282 | l = extract_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum)); |
| 1283 | l = ((l >> 32) & 0xc0000000) | ((l >> 29) & 0x3fffffff); |
| 1284 | store_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype), l); |
| 1285 | } |
| 1286 | else |
| 1287 | error ("Cannot retrieve value from floating point register"); |
| 1288 | } |
| 1289 | |
| 1290 | void |
| 1291 | alpha_register_convert_to_raw (struct type *valtype, int regnum, |
| 1292 | char *virtual_buffer, char *raw_buffer) |
| 1293 | { |
| 1294 | if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum)) |
| 1295 | { |
| 1296 | memcpy (raw_buffer, virtual_buffer, REGISTER_RAW_SIZE (regnum)); |
| 1297 | return; |
| 1298 | } |
| 1299 | |
| 1300 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) |
| 1301 | { |
| 1302 | double d = extract_floating (virtual_buffer, TYPE_LENGTH (valtype)); |
| 1303 | store_floating (raw_buffer, REGISTER_RAW_SIZE (regnum), d); |
| 1304 | } |
| 1305 | else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4) |
| 1306 | { |
| 1307 | ULONGEST l; |
| 1308 | if (TYPE_UNSIGNED (valtype)) |
| 1309 | l = extract_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype)); |
| 1310 | else |
| 1311 | l = extract_signed_integer (virtual_buffer, TYPE_LENGTH (valtype)); |
| 1312 | l = ((l & 0xc0000000) << 32) | ((l & 0x3fffffff) << 29); |
| 1313 | store_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum), l); |
| 1314 | } |
| 1315 | else |
| 1316 | error ("Cannot store value in floating point register"); |
| 1317 | } |
| 1318 | |
| 1319 | /* Given a return value in `regbuf' with a type `valtype', |
| 1320 | extract and copy its value into `valbuf'. */ |
| 1321 | |
| 1322 | void |
| 1323 | alpha_extract_return_value (struct type *valtype, |
| 1324 | char regbuf[REGISTER_BYTES], char *valbuf) |
| 1325 | { |
| 1326 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) |
| 1327 | alpha_register_convert_to_virtual (FP0_REGNUM, valtype, |
| 1328 | regbuf + REGISTER_BYTE (FP0_REGNUM), |
| 1329 | valbuf); |
| 1330 | else |
| 1331 | memcpy (valbuf, regbuf + REGISTER_BYTE (V0_REGNUM), TYPE_LENGTH (valtype)); |
| 1332 | } |
| 1333 | |
| 1334 | /* Given a return value in `regbuf' with a type `valtype', |
| 1335 | write its value into the appropriate register. */ |
| 1336 | |
| 1337 | void |
| 1338 | alpha_store_return_value (struct type *valtype, char *valbuf) |
| 1339 | { |
| 1340 | char raw_buffer[MAX_REGISTER_RAW_SIZE]; |
| 1341 | int regnum = V0_REGNUM; |
| 1342 | int length = TYPE_LENGTH (valtype); |
| 1343 | |
| 1344 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) |
| 1345 | { |
| 1346 | regnum = FP0_REGNUM; |
| 1347 | length = REGISTER_RAW_SIZE (regnum); |
| 1348 | alpha_register_convert_to_raw (valtype, regnum, valbuf, raw_buffer); |
| 1349 | } |
| 1350 | else |
| 1351 | memcpy (raw_buffer, valbuf, length); |
| 1352 | |
| 1353 | write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, length); |
| 1354 | } |
| 1355 | |
| 1356 | /* Just like reinit_frame_cache, but with the right arguments to be |
| 1357 | callable as an sfunc. */ |
| 1358 | |
| 1359 | static void |
| 1360 | reinit_frame_cache_sfunc (char *args, int from_tty, struct cmd_list_element *c) |
| 1361 | { |
| 1362 | reinit_frame_cache (); |
| 1363 | } |
| 1364 | |
| 1365 | /* This is the definition of CALL_DUMMY_ADDRESS. It's a heuristic that is used |
| 1366 | to find a convenient place in the text segment to stick a breakpoint to |
| 1367 | detect the completion of a target function call (ala call_function_by_hand). |
| 1368 | */ |
| 1369 | |
| 1370 | CORE_ADDR |
| 1371 | alpha_call_dummy_address (void) |
| 1372 | { |
| 1373 | CORE_ADDR entry; |
| 1374 | struct minimal_symbol *sym; |
| 1375 | |
| 1376 | entry = entry_point_address (); |
| 1377 | |
| 1378 | if (entry != 0) |
| 1379 | return entry; |
| 1380 | |
| 1381 | sym = lookup_minimal_symbol ("_Prelude", NULL, symfile_objfile); |
| 1382 | |
| 1383 | if (!sym || MSYMBOL_TYPE (sym) != mst_text) |
| 1384 | return 0; |
| 1385 | else |
| 1386 | return SYMBOL_VALUE_ADDRESS (sym) + 4; |
| 1387 | } |
| 1388 | |
| 1389 | void |
| 1390 | _initialize_alpha_tdep (void) |
| 1391 | { |
| 1392 | struct cmd_list_element *c; |
| 1393 | |
| 1394 | tm_print_insn = print_insn_alpha; |
| 1395 | |
| 1396 | /* Let the user set the fence post for heuristic_proc_start. */ |
| 1397 | |
| 1398 | /* We really would like to have both "0" and "unlimited" work, but |
| 1399 | command.c doesn't deal with that. So make it a var_zinteger |
| 1400 | because the user can always use "999999" or some such for unlimited. */ |
| 1401 | c = add_set_cmd ("heuristic-fence-post", class_support, var_zinteger, |
| 1402 | (char *) &heuristic_fence_post, |
| 1403 | "\ |
| 1404 | Set the distance searched for the start of a function.\n\ |
| 1405 | If you are debugging a stripped executable, GDB needs to search through the\n\ |
| 1406 | program for the start of a function. This command sets the distance of the\n\ |
| 1407 | search. The only need to set it is when debugging a stripped executable.", |
| 1408 | &setlist); |
| 1409 | /* We need to throw away the frame cache when we set this, since it |
| 1410 | might change our ability to get backtraces. */ |
| 1411 | c->function.sfunc = reinit_frame_cache_sfunc; |
| 1412 | add_show_from_set (c, &showlist); |
| 1413 | } |