| 1 | /* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger. |
| 2 | Copyright 1993 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "frame.h" |
| 22 | #include "inferior.h" |
| 23 | #include "symtab.h" |
| 24 | #include "value.h" |
| 25 | #include "gdbcmd.h" |
| 26 | #include "gdbcore.h" |
| 27 | #include "dis-asm.h" |
| 28 | |
| 29 | /* FIXME: Some of this code should perhaps be merged with mips-tdep.c. */ |
| 30 | |
| 31 | #define VM_MIN_ADDRESS (CORE_ADDR)0x120000000 |
| 32 | \f |
| 33 | |
| 34 | /* Forward declarations. */ |
| 35 | |
| 36 | static CORE_ADDR |
| 37 | read_next_frame_reg PARAMS ((FRAME, int)); |
| 38 | |
| 39 | static CORE_ADDR |
| 40 | heuristic_proc_start PARAMS ((CORE_ADDR)); |
| 41 | |
| 42 | static alpha_extra_func_info_t |
| 43 | heuristic_proc_desc PARAMS ((CORE_ADDR, CORE_ADDR, FRAME)); |
| 44 | |
| 45 | static alpha_extra_func_info_t |
| 46 | find_proc_desc PARAMS ((CORE_ADDR, FRAME)); |
| 47 | |
| 48 | static int |
| 49 | alpha_in_lenient_prologue PARAMS ((CORE_ADDR, CORE_ADDR)); |
| 50 | |
| 51 | static void |
| 52 | reinit_frame_cache_sfunc PARAMS ((char *, int, struct cmd_list_element *)); |
| 53 | |
| 54 | void |
| 55 | _initialize_alpha_tdep PARAMS ((void)); |
| 56 | |
| 57 | /* Heuristic_proc_start may hunt through the text section for a long |
| 58 | time across a 2400 baud serial line. Allows the user to limit this |
| 59 | search. */ |
| 60 | static unsigned int heuristic_fence_post = 0; |
| 61 | |
| 62 | /* Layout of a stack frame on the alpha: |
| 63 | |
| 64 | | | |
| 65 | pdr members: | 7th ... nth arg, | |
| 66 | | `pushed' by caller. | |
| 67 | | | |
| 68 | ----------------|-------------------------------|<-- old_sp == vfp |
| 69 | ^ ^ ^ ^ | | |
| 70 | | | | | | | |
| 71 | | |localoff | Copies of 1st .. 6th | |
| 72 | | | | | | argument if necessary. | |
| 73 | | | | v | | |
| 74 | | | | --- |-------------------------------|<-- FRAME_ARGS_ADDRESS, |
| 75 | | | | | | FRAME_LOCALS_ADDRESS |
| 76 | | | | | Locals and temporaries. | |
| 77 | | | | | | |
| 78 | | | | |-------------------------------| |
| 79 | | | | | | |
| 80 | |-fregoffset | Saved float registers. | |
| 81 | | | | | F9 | |
| 82 | | | | | . | |
| 83 | | | | | . | |
| 84 | | | | | F2 | |
| 85 | | | v | | |
| 86 | | | -------|-------------------------------| |
| 87 | | | | | |
| 88 | | | | Saved registers. | |
| 89 | | | | S6 | |
| 90 | |-regoffset | . | |
| 91 | | | | . | |
| 92 | | | | S0 | |
| 93 | | | | pdr.pcreg | |
| 94 | | v | | |
| 95 | | ----------|-------------------------------| |
| 96 | | | | |
| 97 | frameoffset | Argument build area, gets | |
| 98 | | | 7th ... nth arg for any | |
| 99 | | | called procedure. | |
| 100 | v | | |
| 101 | -------------|-------------------------------|<-- sp |
| 102 | | | |
| 103 | */ |
| 104 | |
| 105 | #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */ |
| 106 | #define PROC_HIGH_ADDR(proc) ((proc)->pdr.iline) /* upper address bound */ |
| 107 | #define PROC_DUMMY_FRAME(proc) ((proc)->pdr.iopt) /* frame for CALL_DUMMY */ |
| 108 | #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset) |
| 109 | #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg) |
| 110 | #define PROC_REG_MASK(proc) ((proc)->pdr.regmask) |
| 111 | #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask) |
| 112 | #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset) |
| 113 | #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset) |
| 114 | #define PROC_PC_REG(proc) ((proc)->pdr.pcreg) |
| 115 | #define PROC_LOCALOFF(proc) ((proc)->pdr.localoff) |
| 116 | #define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym) |
| 117 | #define _PROC_MAGIC_ 0x0F0F0F0F |
| 118 | #define PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym == _PROC_MAGIC_) |
| 119 | #define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym = _PROC_MAGIC_) |
| 120 | |
| 121 | struct linked_proc_info |
| 122 | { |
| 123 | struct alpha_extra_func_info info; |
| 124 | struct linked_proc_info *next; |
| 125 | } *linked_proc_desc_table = NULL; |
| 126 | |
| 127 | \f |
| 128 | #define READ_FRAME_REG(fi, regno) read_next_frame_reg((fi)->next, regno) |
| 129 | |
| 130 | static CORE_ADDR |
| 131 | read_next_frame_reg(fi, regno) |
| 132 | FRAME fi; |
| 133 | int regno; |
| 134 | { |
| 135 | /* If it is the frame for sigtramp we have a pointer to the sigcontext |
| 136 | on the stack. |
| 137 | If the stack layout for __sigtramp changes or if sigcontext offsets |
| 138 | change we might have to update this code. */ |
| 139 | #ifndef SIGFRAME_PC_OFF |
| 140 | #define SIGFRAME_PC_OFF (2 * 8) |
| 141 | #define SIGFRAME_REGSAVE_OFF (4 * 8) |
| 142 | #endif |
| 143 | for (; fi; fi = fi->next) |
| 144 | { |
| 145 | if (fi->signal_handler_caller) |
| 146 | { |
| 147 | int offset; |
| 148 | CORE_ADDR sigcontext_addr = read_memory_integer(fi->frame, 8); |
| 149 | |
| 150 | if (regno == PC_REGNUM) |
| 151 | offset = SIGFRAME_PC_OFF; |
| 152 | else if (regno < 32) |
| 153 | offset = SIGFRAME_REGSAVE_OFF + regno * 8; |
| 154 | else |
| 155 | return 0; |
| 156 | return read_memory_integer(sigcontext_addr + offset, 8); |
| 157 | } |
| 158 | else if (regno == SP_REGNUM) |
| 159 | return fi->frame; |
| 160 | else if (fi->saved_regs->regs[regno]) |
| 161 | return read_memory_integer(fi->saved_regs->regs[regno], 8); |
| 162 | } |
| 163 | return read_register(regno); |
| 164 | } |
| 165 | |
| 166 | CORE_ADDR |
| 167 | alpha_frame_saved_pc(frame) |
| 168 | FRAME frame; |
| 169 | { |
| 170 | alpha_extra_func_info_t proc_desc = frame->proc_desc; |
| 171 | int pcreg = proc_desc ? PROC_PC_REG(proc_desc) : RA_REGNUM; |
| 172 | |
| 173 | if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc)) |
| 174 | return read_memory_integer(frame->frame - 8, 8); |
| 175 | |
| 176 | return read_next_frame_reg(frame, pcreg); |
| 177 | } |
| 178 | |
| 179 | CORE_ADDR |
| 180 | alpha_saved_pc_after_call (frame) |
| 181 | FRAME frame; |
| 182 | { |
| 183 | alpha_extra_func_info_t proc_desc = find_proc_desc (frame->pc, frame->next); |
| 184 | int pcreg = proc_desc ? PROC_PC_REG (proc_desc) : RA_REGNUM; |
| 185 | |
| 186 | return read_register (pcreg); |
| 187 | } |
| 188 | |
| 189 | |
| 190 | static struct alpha_extra_func_info temp_proc_desc; |
| 191 | static struct frame_saved_regs temp_saved_regs; |
| 192 | |
| 193 | /* This fencepost looks highly suspicious to me. Removing it also |
| 194 | seems suspicious as it could affect remote debugging across serial |
| 195 | lines. */ |
| 196 | |
| 197 | static CORE_ADDR |
| 198 | heuristic_proc_start(pc) |
| 199 | CORE_ADDR pc; |
| 200 | { |
| 201 | CORE_ADDR start_pc = pc; |
| 202 | CORE_ADDR fence = start_pc - heuristic_fence_post; |
| 203 | |
| 204 | if (start_pc == 0) return 0; |
| 205 | |
| 206 | if (heuristic_fence_post == UINT_MAX |
| 207 | || fence < VM_MIN_ADDRESS) |
| 208 | fence = VM_MIN_ADDRESS; |
| 209 | |
| 210 | /* search back for previous return */ |
| 211 | for (start_pc -= 4; ; start_pc -= 4) |
| 212 | if (start_pc < fence) |
| 213 | { |
| 214 | /* It's not clear to me why we reach this point when |
| 215 | stop_soon_quietly, but with this test, at least we |
| 216 | don't print out warnings for every child forked (eg, on |
| 217 | decstation). 22apr93 rich@cygnus.com. */ |
| 218 | if (!stop_soon_quietly) |
| 219 | { |
| 220 | static int blurb_printed = 0; |
| 221 | |
| 222 | if (fence == VM_MIN_ADDRESS) |
| 223 | warning("Hit beginning of text section without finding"); |
| 224 | else |
| 225 | warning("Hit heuristic-fence-post without finding"); |
| 226 | |
| 227 | warning("enclosing function for address 0x%lx", pc); |
| 228 | if (!blurb_printed) |
| 229 | { |
| 230 | printf_filtered ("\ |
| 231 | This warning occurs if you are debugging a function without any symbols\n\ |
| 232 | (for example, in a stripped executable). In that case, you may wish to\n\ |
| 233 | increase the size of the search with the `set heuristic-fence-post' command.\n\ |
| 234 | \n\ |
| 235 | Otherwise, you told GDB there was a function where there isn't one, or\n\ |
| 236 | (more likely) you have encountered a bug in GDB.\n"); |
| 237 | blurb_printed = 1; |
| 238 | } |
| 239 | } |
| 240 | |
| 241 | return 0; |
| 242 | } |
| 243 | else if (ABOUT_TO_RETURN(start_pc)) |
| 244 | break; |
| 245 | |
| 246 | start_pc += 4; /* skip return */ |
| 247 | return start_pc; |
| 248 | } |
| 249 | |
| 250 | static alpha_extra_func_info_t |
| 251 | heuristic_proc_desc(start_pc, limit_pc, next_frame) |
| 252 | CORE_ADDR start_pc, limit_pc; |
| 253 | FRAME next_frame; |
| 254 | { |
| 255 | CORE_ADDR sp = next_frame ? next_frame->frame : read_register (SP_REGNUM); |
| 256 | CORE_ADDR cur_pc; |
| 257 | int frame_size; |
| 258 | int has_frame_reg = 0; |
| 259 | unsigned long reg_mask = 0; |
| 260 | |
| 261 | if (start_pc == 0) |
| 262 | return NULL; |
| 263 | memset(&temp_proc_desc, '\0', sizeof(temp_proc_desc)); |
| 264 | memset(&temp_saved_regs, '\0', sizeof(struct frame_saved_regs)); |
| 265 | PROC_LOW_ADDR(&temp_proc_desc) = start_pc; |
| 266 | |
| 267 | if (start_pc + 200 < limit_pc) |
| 268 | limit_pc = start_pc + 200; |
| 269 | frame_size = 0; |
| 270 | for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4) |
| 271 | { |
| 272 | char buf[4]; |
| 273 | unsigned long word; |
| 274 | int status; |
| 275 | |
| 276 | status = read_memory_nobpt (cur_pc, buf, 4); |
| 277 | if (status) |
| 278 | memory_error (status, cur_pc); |
| 279 | word = extract_unsigned_integer (buf, 4); |
| 280 | |
| 281 | if ((word & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */ |
| 282 | frame_size += (-word) & 0xffff; |
| 283 | else if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */ |
| 284 | && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */ |
| 285 | { |
| 286 | int reg = (word & 0x03e00000) >> 21; |
| 287 | reg_mask |= 1 << reg; |
| 288 | temp_saved_regs.regs[reg] = sp + (short)word; |
| 289 | } |
| 290 | else if (word == 0x47de040f) /* bis sp,sp fp */ |
| 291 | has_frame_reg = 1; |
| 292 | } |
| 293 | if (has_frame_reg) |
| 294 | PROC_FRAME_REG(&temp_proc_desc) = GCC_FP_REGNUM; |
| 295 | else |
| 296 | PROC_FRAME_REG(&temp_proc_desc) = SP_REGNUM; |
| 297 | PROC_FRAME_OFFSET(&temp_proc_desc) = frame_size; |
| 298 | PROC_REG_MASK(&temp_proc_desc) = reg_mask; |
| 299 | PROC_PC_REG(&temp_proc_desc) = RA_REGNUM; |
| 300 | return &temp_proc_desc; |
| 301 | } |
| 302 | |
| 303 | static alpha_extra_func_info_t |
| 304 | find_proc_desc(pc, next_frame) |
| 305 | CORE_ADDR pc; |
| 306 | FRAME next_frame; |
| 307 | { |
| 308 | alpha_extra_func_info_t proc_desc; |
| 309 | struct block *b; |
| 310 | struct symbol *sym; |
| 311 | CORE_ADDR startaddr; |
| 312 | |
| 313 | /* Try to get the proc_desc from the linked call dummy proc_descs |
| 314 | if the pc is in the call dummy. |
| 315 | This is hairy. In the case of nested dummy calls we have to find the |
| 316 | right proc_desc, but we might not yet know the frame for the dummy |
| 317 | as it will be contained in the proc_desc we are searching for. |
| 318 | So we have to find the proc_desc whose frame is closest to the current |
| 319 | stack pointer. */ |
| 320 | if (PC_IN_CALL_DUMMY (pc, 0, 0)) |
| 321 | { |
| 322 | struct linked_proc_info *link; |
| 323 | CORE_ADDR sp = next_frame ? next_frame->frame : read_register (SP_REGNUM); |
| 324 | alpha_extra_func_info_t found_proc_desc = NULL; |
| 325 | long min_distance = LONG_MAX; |
| 326 | |
| 327 | for (link = linked_proc_desc_table; link; link = link->next) |
| 328 | { |
| 329 | long distance = (CORE_ADDR) PROC_DUMMY_FRAME (&link->info) - sp; |
| 330 | if (distance > 0 && distance < min_distance) |
| 331 | { |
| 332 | min_distance = distance; |
| 333 | found_proc_desc = &link->info; |
| 334 | } |
| 335 | } |
| 336 | if (found_proc_desc != NULL) |
| 337 | return found_proc_desc; |
| 338 | } |
| 339 | |
| 340 | b = block_for_pc(pc); |
| 341 | find_pc_partial_function (pc, NULL, &startaddr, NULL); |
| 342 | if (b == NULL) |
| 343 | sym = NULL; |
| 344 | else |
| 345 | { |
| 346 | if (startaddr > BLOCK_START (b)) |
| 347 | /* This is the "pathological" case referred to in a comment in |
| 348 | print_frame_info. It might be better to move this check into |
| 349 | symbol reading. */ |
| 350 | sym = NULL; |
| 351 | else |
| 352 | sym = lookup_symbol (MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE, |
| 353 | 0, NULL); |
| 354 | } |
| 355 | |
| 356 | if (sym) |
| 357 | { |
| 358 | /* IF (this is the topmost frame OR a frame interrupted by a signal) |
| 359 | * AND (this proc does not have debugging information OR |
| 360 | * the PC is in the procedure prologue) |
| 361 | * THEN create a "heuristic" proc_desc (by analyzing |
| 362 | * the actual code) to replace the "official" proc_desc. |
| 363 | */ |
| 364 | proc_desc = (alpha_extra_func_info_t)SYMBOL_VALUE(sym); |
| 365 | if (next_frame == NULL || next_frame->signal_handler_caller) { |
| 366 | struct symtab_and_line val; |
| 367 | struct symbol *proc_symbol = |
| 368 | PROC_DESC_IS_DUMMY(proc_desc) ? 0 : PROC_SYMBOL(proc_desc); |
| 369 | |
| 370 | if (proc_symbol) { |
| 371 | val = find_pc_line (BLOCK_START |
| 372 | (SYMBOL_BLOCK_VALUE(proc_symbol)), |
| 373 | 0); |
| 374 | val.pc = val.end ? val.end : pc; |
| 375 | } |
| 376 | if (!proc_symbol || pc < val.pc) { |
| 377 | alpha_extra_func_info_t found_heuristic = |
| 378 | heuristic_proc_desc(PROC_LOW_ADDR(proc_desc), |
| 379 | pc, next_frame); |
| 380 | if (found_heuristic) |
| 381 | { |
| 382 | /* The call to heuristic_proc_desc determines |
| 383 | which registers have been saved so far and if the |
| 384 | frame is already set up. |
| 385 | The heuristic algorithm doesn't work well for other |
| 386 | information in the procedure descriptor, so copy |
| 387 | it from the found procedure descriptor. */ |
| 388 | PROC_LOCALOFF(found_heuristic) = PROC_LOCALOFF(proc_desc); |
| 389 | PROC_PC_REG(found_heuristic) = PROC_PC_REG(proc_desc); |
| 390 | proc_desc = found_heuristic; |
| 391 | } |
| 392 | } |
| 393 | } |
| 394 | } |
| 395 | else |
| 396 | { |
| 397 | if (startaddr == 0) |
| 398 | startaddr = heuristic_proc_start (pc); |
| 399 | |
| 400 | proc_desc = |
| 401 | heuristic_proc_desc (startaddr, pc, next_frame); |
| 402 | } |
| 403 | return proc_desc; |
| 404 | } |
| 405 | |
| 406 | alpha_extra_func_info_t cached_proc_desc; |
| 407 | |
| 408 | FRAME_ADDR |
| 409 | alpha_frame_chain(frame) |
| 410 | FRAME frame; |
| 411 | { |
| 412 | alpha_extra_func_info_t proc_desc; |
| 413 | CORE_ADDR saved_pc = FRAME_SAVED_PC(frame); |
| 414 | |
| 415 | if (saved_pc == 0 || inside_entry_file (saved_pc)) |
| 416 | return 0; |
| 417 | |
| 418 | proc_desc = find_proc_desc(saved_pc, frame); |
| 419 | if (!proc_desc) |
| 420 | return 0; |
| 421 | |
| 422 | cached_proc_desc = proc_desc; |
| 423 | |
| 424 | /* Fetch the frame pointer for a dummy frame from the procedure |
| 425 | descriptor. */ |
| 426 | if (PROC_DESC_IS_DUMMY(proc_desc)) |
| 427 | return (FRAME_ADDR) PROC_DUMMY_FRAME(proc_desc); |
| 428 | |
| 429 | /* If no frame pointer and frame size is zero, we must be at end |
| 430 | of stack (or otherwise hosed). If we don't check frame size, |
| 431 | we loop forever if we see a zero size frame. */ |
| 432 | if (PROC_FRAME_REG (proc_desc) == SP_REGNUM |
| 433 | && PROC_FRAME_OFFSET (proc_desc) == 0 |
| 434 | /* The alpha __sigtramp routine is frameless and has a frame size |
| 435 | of zero. Luckily it is the only procedure which has PC_REGNUM |
| 436 | as PROC_PC_REG. */ |
| 437 | && PROC_PC_REG (proc_desc) != PC_REGNUM |
| 438 | /* The previous frame from a sigtramp frame might be frameless |
| 439 | and have frame size zero. */ |
| 440 | && !frame->signal_handler_caller) |
| 441 | return 0; |
| 442 | else |
| 443 | return read_next_frame_reg(frame, PROC_FRAME_REG(proc_desc)) |
| 444 | + PROC_FRAME_OFFSET(proc_desc); |
| 445 | } |
| 446 | |
| 447 | void |
| 448 | init_extra_frame_info(fci) |
| 449 | struct frame_info *fci; |
| 450 | { |
| 451 | extern struct obstack frame_cache_obstack; |
| 452 | /* Use proc_desc calculated in frame_chain */ |
| 453 | alpha_extra_func_info_t proc_desc = |
| 454 | fci->next ? cached_proc_desc : find_proc_desc(fci->pc, fci->next); |
| 455 | |
| 456 | fci->saved_regs = (struct frame_saved_regs*) |
| 457 | obstack_alloc (&frame_cache_obstack, sizeof(struct frame_saved_regs)); |
| 458 | memset (fci->saved_regs, 0, sizeof (struct frame_saved_regs)); |
| 459 | fci->proc_desc = |
| 460 | proc_desc == &temp_proc_desc ? 0 : proc_desc; |
| 461 | if (proc_desc) |
| 462 | { |
| 463 | int ireg; |
| 464 | CORE_ADDR reg_position; |
| 465 | unsigned long mask; |
| 466 | int returnreg; |
| 467 | |
| 468 | /* Get the locals offset from the procedure descriptor, it is valid |
| 469 | even if we are in the middle of the prologue. */ |
| 470 | fci->localoff = PROC_LOCALOFF(proc_desc); |
| 471 | |
| 472 | /* FIXME: This is a kludge for gcc-2.4.5. |
| 473 | gcc-2.4.5 builds frames for the alpha in a peculiar way. |
| 474 | It uses $fp as a frame register (which seems to be identical to $sp |
| 475 | in all procedures that do not use alloca). |
| 476 | It has the arguments and the locals above the frame register, if |
| 477 | there are few arguments then the locals are above the arguments, |
| 478 | otherwise the arguments are above the local. |
| 479 | Frame offsets for arguments and locals are relative to $fp and always |
| 480 | positive. |
| 481 | If we want to stay compatible with the native cc compiler we have |
| 482 | to set localoff to frameoffset so that FRAME_ARGS_ADDRESS and |
| 483 | FRAME_LOCALS_ADDRESS point to the right place in the frame. |
| 484 | Please note that the setting of localoff in the compiler won't work |
| 485 | as localoff is only 8 bits wide (which is enough for cc as it needs |
| 486 | at most number_of_arg_regs * 8 == 48). */ |
| 487 | if (PROC_FRAME_REG(proc_desc) == GCC_FP_REGNUM) |
| 488 | fci->localoff = PROC_FRAME_OFFSET(proc_desc); |
| 489 | |
| 490 | /* Fixup frame-pointer - only needed for top frame */ |
| 491 | /* Fetch the frame pointer for a dummy frame from the procedure |
| 492 | descriptor. */ |
| 493 | if (PROC_DESC_IS_DUMMY(proc_desc)) |
| 494 | fci->frame = (FRAME_ADDR) PROC_DUMMY_FRAME(proc_desc); |
| 495 | /* This may not be quite right, if proc has a real frame register. |
| 496 | Get the value of the frame relative sp, procedure might have been |
| 497 | interrupted by a signal at it's very start. */ |
| 498 | else if (fci->pc == PROC_LOW_ADDR(proc_desc)) |
| 499 | fci->frame = READ_FRAME_REG(fci, SP_REGNUM); |
| 500 | else |
| 501 | fci->frame = READ_FRAME_REG(fci, PROC_FRAME_REG(proc_desc)) |
| 502 | + PROC_FRAME_OFFSET(proc_desc); |
| 503 | |
| 504 | /* If this is the innermost frame, and we are still in the |
| 505 | prologue (loosely defined), then the registers may not have |
| 506 | been saved yet. */ |
| 507 | if (fci->next == NULL |
| 508 | && !PROC_DESC_IS_DUMMY(proc_desc) |
| 509 | && alpha_in_lenient_prologue (PROC_LOW_ADDR (proc_desc), fci->pc)) |
| 510 | { |
| 511 | /* Can't just say that the registers are not saved, because they |
| 512 | might get clobbered halfway through the prologue. |
| 513 | heuristic_proc_desc already has the right code to figure out |
| 514 | exactly what has been saved, so use it. As far as I know we |
| 515 | could be doing this (as we do on the 68k, for example) |
| 516 | regardless of whether we are in the prologue; I'm leaving in |
| 517 | the check for being in the prologue only out of conservatism |
| 518 | (I'm not sure whether heuristic_proc_desc handles all cases, |
| 519 | for example). |
| 520 | |
| 521 | This stuff is ugly (and getting uglier by the minute). Probably |
| 522 | the best way to clean it up is to ignore the proc_desc's from |
| 523 | the symbols altogher, and get all the information we need by |
| 524 | examining the prologue (provided we can make the prologue |
| 525 | examining code good enough to get all the cases...). */ |
| 526 | proc_desc = |
| 527 | heuristic_proc_desc (PROC_LOW_ADDR (proc_desc), |
| 528 | fci->pc, |
| 529 | fci->next); |
| 530 | } |
| 531 | |
| 532 | if (proc_desc == &temp_proc_desc) |
| 533 | *fci->saved_regs = temp_saved_regs; |
| 534 | else |
| 535 | { |
| 536 | /* Find which general-purpose registers were saved. |
| 537 | The return address register is the first saved register, |
| 538 | the other registers follow in ascending order. */ |
| 539 | reg_position = fci->frame + PROC_REG_OFFSET(proc_desc); |
| 540 | mask = PROC_REG_MASK(proc_desc) & 0xffffffffL; |
| 541 | returnreg = PROC_PC_REG(proc_desc); |
| 542 | if (mask & (1 << returnreg)) |
| 543 | { |
| 544 | fci->saved_regs->regs[returnreg] = reg_position; |
| 545 | reg_position += 8; |
| 546 | } |
| 547 | for (ireg = 0; mask; ireg++, mask >>= 1) |
| 548 | if (mask & 1) |
| 549 | { |
| 550 | if (ireg == returnreg) |
| 551 | continue; |
| 552 | fci->saved_regs->regs[ireg] = reg_position; |
| 553 | reg_position += 8; |
| 554 | } |
| 555 | /* find which floating-point registers were saved */ |
| 556 | reg_position = fci->frame + PROC_FREG_OFFSET(proc_desc); |
| 557 | mask = PROC_FREG_MASK(proc_desc) & 0xffffffffL; |
| 558 | for (ireg = 0; mask; ireg++, mask >>= 1) |
| 559 | if (mask & 1) |
| 560 | { |
| 561 | fci->saved_regs->regs[FP0_REGNUM+ireg] = reg_position; |
| 562 | reg_position += 8; |
| 563 | } |
| 564 | } |
| 565 | |
| 566 | fci->saved_regs->regs[PC_REGNUM] = fci->saved_regs->regs[PROC_PC_REG(proc_desc)]; |
| 567 | } |
| 568 | } |
| 569 | |
| 570 | /* ALPHA stack frames are almost impenetrable. When execution stops, |
| 571 | we basically have to look at symbol information for the function |
| 572 | that we stopped in, which tells us *which* register (if any) is |
| 573 | the base of the frame pointer, and what offset from that register |
| 574 | the frame itself is at. |
| 575 | |
| 576 | This presents a problem when trying to examine a stack in memory |
| 577 | (that isn't executing at the moment), using the "frame" command. We |
| 578 | don't have a PC, nor do we have any registers except SP. |
| 579 | |
| 580 | This routine takes two arguments, SP and PC, and tries to make the |
| 581 | cached frames look as if these two arguments defined a frame on the |
| 582 | cache. This allows the rest of info frame to extract the important |
| 583 | arguments without difficulty. */ |
| 584 | |
| 585 | FRAME |
| 586 | setup_arbitrary_frame (argc, argv) |
| 587 | int argc; |
| 588 | FRAME_ADDR *argv; |
| 589 | { |
| 590 | if (argc != 2) |
| 591 | error ("ALPHA frame specifications require two arguments: sp and pc"); |
| 592 | |
| 593 | return create_new_frame (argv[0], argv[1]); |
| 594 | } |
| 595 | |
| 596 | /* The alpha passes the first six arguments in the registers, the rest on |
| 597 | the stack. The register arguments are eventually transferred to the |
| 598 | argument transfer area immediately below the stack by the called function |
| 599 | anyway. So we `push' at least six arguments on the stack, `reload' the |
| 600 | argument registers and then adjust the stack pointer to point past the |
| 601 | sixth argument. This algorithm simplifies the passing of a large struct |
| 602 | which extends from the registers to the stack. |
| 603 | If the called function is returning a structure, the address of the |
| 604 | structure to be returned is passed as a hidden first argument. */ |
| 605 | |
| 606 | #define NUM_ARG_REGS 6 |
| 607 | |
| 608 | CORE_ADDR |
| 609 | alpha_push_arguments (nargs, args, sp, struct_return, struct_addr) |
| 610 | int nargs; |
| 611 | value *args; |
| 612 | CORE_ADDR sp; |
| 613 | int struct_return; |
| 614 | CORE_ADDR struct_addr; |
| 615 | { |
| 616 | register i; |
| 617 | int accumulate_size = struct_return ? 8 : 0; |
| 618 | int arg_regs_size = NUM_ARG_REGS * 8; |
| 619 | struct alpha_arg { char *contents; int len; int offset; }; |
| 620 | struct alpha_arg *alpha_args = |
| 621 | (struct alpha_arg*)alloca (nargs * sizeof (struct alpha_arg)); |
| 622 | register struct alpha_arg *m_arg; |
| 623 | char raw_buffer[sizeof (CORE_ADDR)]; |
| 624 | int required_arg_regs; |
| 625 | |
| 626 | for (i = 0, m_arg = alpha_args; i < nargs; i++, m_arg++) |
| 627 | { |
| 628 | value arg = value_arg_coerce (args[i]); |
| 629 | /* Cast argument to long if necessary as the compiler does it too. */ |
| 630 | if (TYPE_LENGTH (VALUE_TYPE (arg)) < TYPE_LENGTH (builtin_type_long)) |
| 631 | arg = value_cast (builtin_type_long, arg); |
| 632 | m_arg->len = TYPE_LENGTH (VALUE_TYPE (arg)); |
| 633 | m_arg->offset = accumulate_size; |
| 634 | accumulate_size = (accumulate_size + m_arg->len + 7) & ~7; |
| 635 | m_arg->contents = VALUE_CONTENTS(arg); |
| 636 | } |
| 637 | |
| 638 | /* Determine required argument register loads, loading an argument register |
| 639 | is expensive as it uses three ptrace calls. */ |
| 640 | required_arg_regs = accumulate_size / 8; |
| 641 | if (required_arg_regs > NUM_ARG_REGS) |
| 642 | required_arg_regs = NUM_ARG_REGS; |
| 643 | |
| 644 | /* Make room for the arguments on the stack. */ |
| 645 | if (accumulate_size < arg_regs_size) |
| 646 | accumulate_size = arg_regs_size; |
| 647 | sp -= accumulate_size; |
| 648 | |
| 649 | /* Keep sp aligned to a multiple of 16 as the compiler does it too. */ |
| 650 | sp &= ~15; |
| 651 | |
| 652 | /* `Push' arguments on the stack. */ |
| 653 | for (i = nargs; m_arg--, --i >= 0; ) |
| 654 | write_memory(sp + m_arg->offset, m_arg->contents, m_arg->len); |
| 655 | if (struct_return) |
| 656 | { |
| 657 | store_address (raw_buffer, sizeof (CORE_ADDR), struct_addr); |
| 658 | write_memory (sp, raw_buffer, sizeof (CORE_ADDR)); |
| 659 | } |
| 660 | |
| 661 | /* Load the argument registers. */ |
| 662 | for (i = 0; i < required_arg_regs; i++) |
| 663 | { |
| 664 | LONGEST val; |
| 665 | |
| 666 | val = read_memory_integer (sp + i * 8, 8); |
| 667 | write_register (A0_REGNUM + i, val); |
| 668 | write_register (FPA0_REGNUM + i, val); |
| 669 | } |
| 670 | |
| 671 | return sp + arg_regs_size; |
| 672 | } |
| 673 | |
| 674 | void |
| 675 | alpha_push_dummy_frame() |
| 676 | { |
| 677 | int ireg; |
| 678 | struct linked_proc_info *link = (struct linked_proc_info*) |
| 679 | xmalloc(sizeof (struct linked_proc_info)); |
| 680 | alpha_extra_func_info_t proc_desc = &link->info; |
| 681 | CORE_ADDR sp = read_register (SP_REGNUM); |
| 682 | CORE_ADDR save_address; |
| 683 | char raw_buffer[MAX_REGISTER_RAW_SIZE]; |
| 684 | unsigned long mask; |
| 685 | |
| 686 | link->next = linked_proc_desc_table; |
| 687 | linked_proc_desc_table = link; |
| 688 | |
| 689 | /* |
| 690 | * The registers we must save are all those not preserved across |
| 691 | * procedure calls. |
| 692 | * In addition, we must save the PC and RA. |
| 693 | * |
| 694 | * Dummy frame layout: |
| 695 | * (high memory) |
| 696 | * Saved PC |
| 697 | * Saved F30 |
| 698 | * ... |
| 699 | * Saved F0 |
| 700 | * Saved R29 |
| 701 | * ... |
| 702 | * Saved R0 |
| 703 | * Saved R26 (RA) |
| 704 | * Parameter build area |
| 705 | * (low memory) |
| 706 | */ |
| 707 | |
| 708 | /* MASK(i,j) == (1<<i) + (1<<(i+1)) + ... + (1<<j)). Assume i<=j<31. */ |
| 709 | #define MASK(i,j) (((1L << ((j)+1)) - 1) ^ ((1L << (i)) - 1)) |
| 710 | #define GEN_REG_SAVE_MASK (MASK(0,8) | MASK(16,29)) |
| 711 | #define GEN_REG_SAVE_COUNT 24 |
| 712 | #define FLOAT_REG_SAVE_MASK (MASK(0,1) | MASK(10,30)) |
| 713 | #define FLOAT_REG_SAVE_COUNT 23 |
| 714 | /* The special register is the PC as we have no bit for it in the save masks. |
| 715 | alpha_frame_saved_pc knows where the pc is saved in a dummy frame. */ |
| 716 | #define SPECIAL_REG_SAVE_COUNT 1 |
| 717 | |
| 718 | PROC_REG_MASK(proc_desc) = GEN_REG_SAVE_MASK; |
| 719 | PROC_FREG_MASK(proc_desc) = FLOAT_REG_SAVE_MASK; |
| 720 | /* PROC_REG_OFFSET is the offset from the dummy frame to the saved RA, |
| 721 | but keep SP aligned to a multiple of 16. */ |
| 722 | PROC_REG_OFFSET(proc_desc) = |
| 723 | - ((8 * (SPECIAL_REG_SAVE_COUNT |
| 724 | + GEN_REG_SAVE_COUNT |
| 725 | + FLOAT_REG_SAVE_COUNT) |
| 726 | + 15) & ~15); |
| 727 | PROC_FREG_OFFSET(proc_desc) = |
| 728 | PROC_REG_OFFSET(proc_desc) + 8 * GEN_REG_SAVE_COUNT; |
| 729 | |
| 730 | /* Save general registers. |
| 731 | The return address register is the first saved register, all other |
| 732 | registers follow in ascending order. |
| 733 | The PC is saved immediately below the SP. */ |
| 734 | save_address = sp + PROC_REG_OFFSET(proc_desc); |
| 735 | store_address (raw_buffer, 8, read_register (RA_REGNUM)); |
| 736 | write_memory (save_address, raw_buffer, 8); |
| 737 | save_address += 8; |
| 738 | mask = PROC_REG_MASK(proc_desc) & 0xffffffffL; |
| 739 | for (ireg = 0; mask; ireg++, mask >>= 1) |
| 740 | if (mask & 1) |
| 741 | { |
| 742 | if (ireg == RA_REGNUM) |
| 743 | continue; |
| 744 | store_address (raw_buffer, 8, read_register (ireg)); |
| 745 | write_memory (save_address, raw_buffer, 8); |
| 746 | save_address += 8; |
| 747 | } |
| 748 | |
| 749 | store_address (raw_buffer, 8, read_register (PC_REGNUM)); |
| 750 | write_memory (sp - 8, raw_buffer, 8); |
| 751 | |
| 752 | /* Save floating point registers. */ |
| 753 | save_address = sp + PROC_FREG_OFFSET(proc_desc); |
| 754 | mask = PROC_FREG_MASK(proc_desc) & 0xffffffffL; |
| 755 | for (ireg = 0; mask; ireg++, mask >>= 1) |
| 756 | if (mask & 1) |
| 757 | { |
| 758 | store_address (raw_buffer, 8, read_register (ireg + FP0_REGNUM)); |
| 759 | write_memory (save_address, raw_buffer, 8); |
| 760 | save_address += 8; |
| 761 | } |
| 762 | |
| 763 | /* Set and save the frame address for the dummy. |
| 764 | This is tricky. The only registers that are suitable for a frame save |
| 765 | are those that are preserved across procedure calls (s0-s6). But if |
| 766 | a read system call is interrupted and then a dummy call is made |
| 767 | (see testsuite/gdb.t17/interrupt.exp) the dummy call hangs till the read |
| 768 | is satisfied. Then it returns with the s0-s6 registers set to the values |
| 769 | on entry to the read system call and our dummy frame pointer would be |
| 770 | destroyed. So we save the dummy frame in the proc_desc and handle the |
| 771 | retrieval of the frame pointer of a dummy specifically. The frame register |
| 772 | is set to the virtual frame (pseudo) register, it's value will always |
| 773 | be read as zero and will help us to catch any errors in the dummy frame |
| 774 | retrieval code. */ |
| 775 | PROC_DUMMY_FRAME(proc_desc) = sp; |
| 776 | PROC_FRAME_REG(proc_desc) = FP_REGNUM; |
| 777 | PROC_FRAME_OFFSET(proc_desc) = 0; |
| 778 | sp += PROC_REG_OFFSET(proc_desc); |
| 779 | write_register (SP_REGNUM, sp); |
| 780 | |
| 781 | PROC_LOW_ADDR(proc_desc) = entry_point_address (); |
| 782 | PROC_HIGH_ADDR(proc_desc) = PROC_LOW_ADDR(proc_desc) + 4; |
| 783 | |
| 784 | SET_PROC_DESC_IS_DUMMY(proc_desc); |
| 785 | PROC_PC_REG(proc_desc) = RA_REGNUM; |
| 786 | } |
| 787 | |
| 788 | void |
| 789 | alpha_pop_frame() |
| 790 | { |
| 791 | register int regnum; |
| 792 | FRAME frame = get_current_frame (); |
| 793 | CORE_ADDR new_sp = frame->frame; |
| 794 | |
| 795 | alpha_extra_func_info_t proc_desc = frame->proc_desc; |
| 796 | |
| 797 | write_register (PC_REGNUM, FRAME_SAVED_PC(frame)); |
| 798 | if (proc_desc) |
| 799 | { |
| 800 | for (regnum = 32; --regnum >= 0; ) |
| 801 | if (PROC_REG_MASK(proc_desc) & (1 << regnum)) |
| 802 | write_register (regnum, |
| 803 | read_memory_integer (frame->saved_regs->regs[regnum], |
| 804 | 8)); |
| 805 | for (regnum = 32; --regnum >= 0; ) |
| 806 | if (PROC_FREG_MASK(proc_desc) & (1 << regnum)) |
| 807 | write_register (regnum + FP0_REGNUM, |
| 808 | read_memory_integer (frame->saved_regs->regs[regnum + FP0_REGNUM], 8)); |
| 809 | } |
| 810 | write_register (SP_REGNUM, new_sp); |
| 811 | flush_cached_frames (); |
| 812 | /* We let init_extra_frame_info figure out the frame pointer */ |
| 813 | set_current_frame (create_new_frame (0, read_pc ())); |
| 814 | |
| 815 | if (proc_desc && PROC_DESC_IS_DUMMY(proc_desc)) |
| 816 | { |
| 817 | struct linked_proc_info *pi_ptr, *prev_ptr; |
| 818 | |
| 819 | for (pi_ptr = linked_proc_desc_table, prev_ptr = NULL; |
| 820 | pi_ptr != NULL; |
| 821 | prev_ptr = pi_ptr, pi_ptr = pi_ptr->next) |
| 822 | { |
| 823 | if (&pi_ptr->info == proc_desc) |
| 824 | break; |
| 825 | } |
| 826 | |
| 827 | if (pi_ptr == NULL) |
| 828 | error ("Can't locate dummy extra frame info\n"); |
| 829 | |
| 830 | if (prev_ptr != NULL) |
| 831 | prev_ptr->next = pi_ptr->next; |
| 832 | else |
| 833 | linked_proc_desc_table = pi_ptr->next; |
| 834 | |
| 835 | free (pi_ptr); |
| 836 | } |
| 837 | } |
| 838 | \f |
| 839 | /* To skip prologues, I use this predicate. Returns either PC itself |
| 840 | if the code at PC does not look like a function prologue; otherwise |
| 841 | returns an address that (if we're lucky) follows the prologue. If |
| 842 | LENIENT, then we must skip everything which is involved in setting |
| 843 | up the frame (it's OK to skip more, just so long as we don't skip |
| 844 | anything which might clobber the registers which are being saved. |
| 845 | Currently we must not skip more on the alpha, but we might the lenient |
| 846 | stuff some day. */ |
| 847 | |
| 848 | CORE_ADDR |
| 849 | alpha_skip_prologue (pc, lenient) |
| 850 | CORE_ADDR pc; |
| 851 | int lenient; |
| 852 | { |
| 853 | unsigned long inst; |
| 854 | int offset; |
| 855 | |
| 856 | /* Skip the typical prologue instructions. These are the stack adjustment |
| 857 | instruction and the instructions that save registers on the stack |
| 858 | or in the gcc frame. */ |
| 859 | for (offset = 0; offset < 100; offset += 4) |
| 860 | { |
| 861 | char buf[4]; |
| 862 | int status; |
| 863 | |
| 864 | status = read_memory_nobpt (pc + offset, buf, 4); |
| 865 | if (status) |
| 866 | memory_error (status, pc + offset); |
| 867 | inst = extract_unsigned_integer (buf, 4); |
| 868 | |
| 869 | /* The alpha has no delay slots. But let's keep the lenient stuff, |
| 870 | we might need it for something else in the future. */ |
| 871 | if (lenient && 0) |
| 872 | continue; |
| 873 | |
| 874 | if ((inst & 0xffff0000) == 0x27bb0000) /* ldah $gp,n($t12) */ |
| 875 | continue; |
| 876 | if ((inst & 0xffff0000) == 0x23bd0000) /* lda $gp,n($gp) */ |
| 877 | continue; |
| 878 | if ((inst & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */ |
| 879 | continue; |
| 880 | else if ((inst & 0xfc1f0000) == 0xb41e0000 |
| 881 | && (inst & 0xffff0000) != 0xb7fe0000) |
| 882 | continue; /* stq reg,n($sp) */ |
| 883 | /* reg != $zero */ |
| 884 | else if ((inst & 0xfc1f0000) == 0x9c1e0000 |
| 885 | && (inst & 0xffff0000) != 0x9ffe0000) |
| 886 | continue; /* stt reg,n($sp) */ |
| 887 | /* reg != $zero */ |
| 888 | else if (inst == 0x47de040f) /* bis sp,sp,fp */ |
| 889 | continue; |
| 890 | else |
| 891 | break; |
| 892 | } |
| 893 | return pc + offset; |
| 894 | } |
| 895 | |
| 896 | /* Is address PC in the prologue (loosely defined) for function at |
| 897 | STARTADDR? */ |
| 898 | |
| 899 | static int |
| 900 | alpha_in_lenient_prologue (startaddr, pc) |
| 901 | CORE_ADDR startaddr; |
| 902 | CORE_ADDR pc; |
| 903 | { |
| 904 | CORE_ADDR end_prologue = alpha_skip_prologue (startaddr, 1); |
| 905 | return pc >= startaddr && pc < end_prologue; |
| 906 | } |
| 907 | |
| 908 | /* Given a return value in `regbuf' with a type `valtype', |
| 909 | extract and copy its value into `valbuf'. */ |
| 910 | void |
| 911 | alpha_extract_return_value (valtype, regbuf, valbuf) |
| 912 | struct type *valtype; |
| 913 | char regbuf[REGISTER_BYTES]; |
| 914 | char *valbuf; |
| 915 | { |
| 916 | int regnum; |
| 917 | |
| 918 | regnum = TYPE_CODE (valtype) == TYPE_CODE_FLT ? FP0_REGNUM : V0_REGNUM; |
| 919 | |
| 920 | memcpy (valbuf, regbuf + REGISTER_BYTE (regnum), TYPE_LENGTH (valtype)); |
| 921 | } |
| 922 | |
| 923 | /* Given a return value in `regbuf' with a type `valtype', |
| 924 | write it's value into the appropriate register. */ |
| 925 | void |
| 926 | alpha_store_return_value (valtype, valbuf) |
| 927 | struct type *valtype; |
| 928 | char *valbuf; |
| 929 | { |
| 930 | int regnum; |
| 931 | char raw_buffer[MAX_REGISTER_RAW_SIZE]; |
| 932 | |
| 933 | regnum = TYPE_CODE (valtype) == TYPE_CODE_FLT ? FP0_REGNUM : V0_REGNUM; |
| 934 | memcpy(raw_buffer, valbuf, TYPE_LENGTH (valtype)); |
| 935 | |
| 936 | write_register_bytes(REGISTER_BYTE (regnum), raw_buffer, TYPE_LENGTH (valtype)); |
| 937 | } |
| 938 | |
| 939 | /* Print the instruction at address MEMADDR in debugged memory, |
| 940 | on STREAM. Returns length of the instruction, in bytes. */ |
| 941 | |
| 942 | int |
| 943 | print_insn (memaddr, stream) |
| 944 | CORE_ADDR memaddr; |
| 945 | FILE *stream; |
| 946 | { |
| 947 | disassemble_info info; |
| 948 | |
| 949 | GDB_INIT_DISASSEMBLE_INFO(info, stream); |
| 950 | |
| 951 | return print_insn_alpha (memaddr, &info); |
| 952 | } |
| 953 | |
| 954 | /* Just like reinit_frame_cache, but with the right arguments to be |
| 955 | callable as an sfunc. */ |
| 956 | static void |
| 957 | reinit_frame_cache_sfunc (args, from_tty, c) |
| 958 | char *args; |
| 959 | int from_tty; |
| 960 | struct cmd_list_element *c; |
| 961 | { |
| 962 | reinit_frame_cache (); |
| 963 | } |
| 964 | |
| 965 | void |
| 966 | _initialize_alpha_tdep () |
| 967 | { |
| 968 | struct cmd_list_element *c; |
| 969 | |
| 970 | /* Let the user set the fence post for heuristic_proc_start. */ |
| 971 | |
| 972 | /* We really would like to have both "0" and "unlimited" work, but |
| 973 | command.c doesn't deal with that. So make it a var_zinteger |
| 974 | because the user can always use "999999" or some such for unlimited. */ |
| 975 | c = add_set_cmd ("heuristic-fence-post", class_support, var_zinteger, |
| 976 | (char *) &heuristic_fence_post, |
| 977 | "\ |
| 978 | Set the distance searched for the start of a function.\n\ |
| 979 | If you are debugging a stripped executable, GDB needs to search through the\n\ |
| 980 | program for the start of a function. This command sets the distance of the\n\ |
| 981 | search. The only need to set it is when debugging a stripped executable.", |
| 982 | &setlist); |
| 983 | /* We need to throw away the frame cache when we set this, since it |
| 984 | might change our ability to get backtraces. */ |
| 985 | c->function.sfunc = reinit_frame_cache_sfunc; |
| 986 | add_show_from_set (c, &showlist); |
| 987 | } |