| 1 | /* Target-dependent code for the MDEBUG MIPS architecture, for GDB, |
| 2 | the GNU Debugger. |
| 3 | |
| 4 | Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, |
| 5 | 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software |
| 6 | Foundation, Inc. |
| 7 | |
| 8 | This file is part of GDB. |
| 9 | |
| 10 | This program is free software; you can redistribute it and/or modify |
| 11 | it under the terms of the GNU General Public License as published by |
| 12 | the Free Software Foundation; either version 2 of the License, or |
| 13 | (at your option) any later version. |
| 14 | |
| 15 | This program is distributed in the hope that it will be useful, |
| 16 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | GNU General Public License for more details. |
| 19 | |
| 20 | You should have received a copy of the GNU General Public License |
| 21 | along with this program; if not, write to the Free Software |
| 22 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 23 | Boston, MA 02111-1307, USA. */ |
| 24 | |
| 25 | #include "defs.h" |
| 26 | #include "frame.h" |
| 27 | #include "mips-tdep.h" |
| 28 | #include "trad-frame.h" |
| 29 | #include "block.h" |
| 30 | #include "symtab.h" |
| 31 | #include "objfiles.h" |
| 32 | #include "elf/mips.h" |
| 33 | #include "elf-bfd.h" |
| 34 | #include "gdb_assert.h" |
| 35 | #include "frame-unwind.h" |
| 36 | #include "frame-base.h" |
| 37 | #include "mips-mdebug-tdep.h" |
| 38 | #include "mdebugread.h" |
| 39 | |
| 40 | #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */ |
| 41 | #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset) |
| 42 | #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg) |
| 43 | #define PROC_REG_MASK(proc) ((proc)->pdr.regmask) |
| 44 | #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask) |
| 45 | #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset) |
| 46 | #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset) |
| 47 | #define PROC_PC_REG(proc) ((proc)->pdr.pcreg) |
| 48 | /* FIXME drow/2002-06-10: If a pointer on the host is bigger than a long, |
| 49 | this will corrupt pdr.iline. Fortunately we don't use it. */ |
| 50 | #define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym) |
| 51 | #define _PROC_MAGIC_ 0x0F0F0F0F |
| 52 | |
| 53 | struct mips_objfile_private |
| 54 | { |
| 55 | bfd_size_type size; |
| 56 | char *contents; |
| 57 | }; |
| 58 | |
| 59 | /* Global used to communicate between non_heuristic_proc_desc and |
| 60 | compare_pdr_entries within qsort (). */ |
| 61 | static bfd *the_bfd; |
| 62 | |
| 63 | static int |
| 64 | compare_pdr_entries (const void *a, const void *b) |
| 65 | { |
| 66 | CORE_ADDR lhs = bfd_get_32 (the_bfd, (bfd_byte *) a); |
| 67 | CORE_ADDR rhs = bfd_get_32 (the_bfd, (bfd_byte *) b); |
| 68 | |
| 69 | if (lhs < rhs) |
| 70 | return -1; |
| 71 | else if (lhs == rhs) |
| 72 | return 0; |
| 73 | else |
| 74 | return 1; |
| 75 | } |
| 76 | |
| 77 | static const struct objfile_data *mips_pdr_data; |
| 78 | |
| 79 | static struct mdebug_extra_func_info * |
| 80 | non_heuristic_proc_desc (CORE_ADDR pc, CORE_ADDR *addrptr) |
| 81 | { |
| 82 | CORE_ADDR startaddr; |
| 83 | struct mdebug_extra_func_info *proc_desc; |
| 84 | struct block *b = block_for_pc (pc); |
| 85 | struct symbol *sym; |
| 86 | struct obj_section *sec; |
| 87 | struct mips_objfile_private *priv; |
| 88 | |
| 89 | find_pc_partial_function (pc, NULL, &startaddr, NULL); |
| 90 | if (addrptr) |
| 91 | *addrptr = startaddr; |
| 92 | |
| 93 | priv = NULL; |
| 94 | |
| 95 | sec = find_pc_section (pc); |
| 96 | if (sec != NULL) |
| 97 | { |
| 98 | priv = (struct mips_objfile_private *) objfile_data (sec->objfile, mips_pdr_data); |
| 99 | |
| 100 | /* Search the ".pdr" section generated by GAS. This includes most of |
| 101 | the information normally found in ECOFF PDRs. */ |
| 102 | |
| 103 | the_bfd = sec->objfile->obfd; |
| 104 | if (priv == NULL |
| 105 | && (the_bfd->format == bfd_object |
| 106 | && bfd_get_flavour (the_bfd) == bfd_target_elf_flavour |
| 107 | && elf_elfheader (the_bfd)->e_ident[EI_CLASS] == ELFCLASS64)) |
| 108 | { |
| 109 | /* Right now GAS only outputs the address as a four-byte sequence. |
| 110 | This means that we should not bother with this method on 64-bit |
| 111 | targets (until that is fixed). */ |
| 112 | |
| 113 | priv = obstack_alloc (&sec->objfile->objfile_obstack, |
| 114 | sizeof (struct mips_objfile_private)); |
| 115 | priv->size = 0; |
| 116 | set_objfile_data (sec->objfile, mips_pdr_data, priv); |
| 117 | } |
| 118 | else if (priv == NULL) |
| 119 | { |
| 120 | asection *bfdsec; |
| 121 | |
| 122 | priv = obstack_alloc (&sec->objfile->objfile_obstack, |
| 123 | sizeof (struct mips_objfile_private)); |
| 124 | |
| 125 | bfdsec = bfd_get_section_by_name (sec->objfile->obfd, ".pdr"); |
| 126 | if (bfdsec != NULL) |
| 127 | { |
| 128 | priv->size = bfd_section_size (sec->objfile->obfd, bfdsec); |
| 129 | priv->contents = obstack_alloc (&sec->objfile->objfile_obstack, |
| 130 | priv->size); |
| 131 | bfd_get_section_contents (sec->objfile->obfd, bfdsec, |
| 132 | priv->contents, 0, priv->size); |
| 133 | |
| 134 | /* In general, the .pdr section is sorted. However, in the |
| 135 | presence of multiple code sections (and other corner cases) |
| 136 | it can become unsorted. Sort it so that we can use a faster |
| 137 | binary search. */ |
| 138 | qsort (priv->contents, priv->size / 32, 32, |
| 139 | compare_pdr_entries); |
| 140 | } |
| 141 | else |
| 142 | priv->size = 0; |
| 143 | |
| 144 | set_objfile_data (sec->objfile, mips_pdr_data, priv); |
| 145 | } |
| 146 | the_bfd = NULL; |
| 147 | |
| 148 | if (priv->size != 0) |
| 149 | { |
| 150 | int low, mid, high; |
| 151 | char *ptr; |
| 152 | CORE_ADDR pdr_pc; |
| 153 | |
| 154 | low = 0; |
| 155 | high = priv->size / 32; |
| 156 | |
| 157 | /* We've found a .pdr section describing this objfile. We want to |
| 158 | find the entry which describes this code address. The .pdr |
| 159 | information is not very descriptive; we have only a function |
| 160 | start address. We have to look for the closest entry, because |
| 161 | the local symbol at the beginning of this function may have |
| 162 | been stripped - so if we ask the symbol table for the start |
| 163 | address we may get a preceding global function. */ |
| 164 | |
| 165 | /* First, find the last .pdr entry starting at or before PC. */ |
| 166 | do |
| 167 | { |
| 168 | mid = (low + high) / 2; |
| 169 | |
| 170 | ptr = priv->contents + mid * 32; |
| 171 | pdr_pc = bfd_get_signed_32 (sec->objfile->obfd, ptr); |
| 172 | pdr_pc += ANOFFSET (sec->objfile->section_offsets, |
| 173 | SECT_OFF_TEXT (sec->objfile)); |
| 174 | |
| 175 | if (pdr_pc > pc) |
| 176 | high = mid; |
| 177 | else |
| 178 | low = mid + 1; |
| 179 | } |
| 180 | while (low != high); |
| 181 | |
| 182 | /* Both low and high point one past the PDR of interest. If |
| 183 | both are zero, that means this PC is before any region |
| 184 | covered by a PDR, i.e. pdr_pc for the first PDR entry is |
| 185 | greater than PC. */ |
| 186 | if (low > 0) |
| 187 | { |
| 188 | ptr = priv->contents + (low - 1) * 32; |
| 189 | pdr_pc = bfd_get_signed_32 (sec->objfile->obfd, ptr); |
| 190 | pdr_pc += ANOFFSET (sec->objfile->section_offsets, |
| 191 | SECT_OFF_TEXT (sec->objfile)); |
| 192 | } |
| 193 | |
| 194 | /* We don't have a range, so we have no way to know for sure |
| 195 | whether we're in the correct PDR or a PDR for a preceding |
| 196 | function and the current function was a stripped local |
| 197 | symbol. But if the PDR's PC is at least as great as the |
| 198 | best guess from the symbol table, assume that it does cover |
| 199 | the right area; if a .pdr section is present at all then |
| 200 | nearly every function will have an entry. The biggest exception |
| 201 | will be the dynamic linker stubs; conveniently these are |
| 202 | placed before .text instead of after. */ |
| 203 | |
| 204 | if (pc >= pdr_pc && pdr_pc >= startaddr) |
| 205 | { |
| 206 | struct symbol *sym = find_pc_function (pc); |
| 207 | |
| 208 | if (addrptr) |
| 209 | *addrptr = pdr_pc; |
| 210 | |
| 211 | /* Fill in what we need of the proc_desc. */ |
| 212 | proc_desc = (struct mdebug_extra_func_info *) |
| 213 | obstack_alloc (&sec->objfile->objfile_obstack, |
| 214 | sizeof (struct mdebug_extra_func_info)); |
| 215 | PROC_LOW_ADDR (proc_desc) = pdr_pc; |
| 216 | |
| 217 | PROC_FRAME_OFFSET (proc_desc) |
| 218 | = bfd_get_32 (sec->objfile->obfd, ptr + 20); |
| 219 | PROC_FRAME_REG (proc_desc) = bfd_get_32 (sec->objfile->obfd, |
| 220 | ptr + 24); |
| 221 | PROC_REG_MASK (proc_desc) = bfd_get_32 (sec->objfile->obfd, |
| 222 | ptr + 4); |
| 223 | PROC_FREG_MASK (proc_desc) = bfd_get_32 (sec->objfile->obfd, |
| 224 | ptr + 12); |
| 225 | PROC_REG_OFFSET (proc_desc) = bfd_get_32 (sec->objfile->obfd, |
| 226 | ptr + 8); |
| 227 | PROC_FREG_OFFSET (proc_desc) |
| 228 | = bfd_get_32 (sec->objfile->obfd, ptr + 16); |
| 229 | PROC_PC_REG (proc_desc) = bfd_get_32 (sec->objfile->obfd, |
| 230 | ptr + 28); |
| 231 | proc_desc->pdr.isym = (long) sym; |
| 232 | |
| 233 | return proc_desc; |
| 234 | } |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | if (b == NULL) |
| 239 | return NULL; |
| 240 | |
| 241 | if (startaddr > BLOCK_START (b)) |
| 242 | { |
| 243 | /* This is the "pathological" case referred to in a comment in |
| 244 | print_frame_info. It might be better to move this check into |
| 245 | symbol reading. */ |
| 246 | return NULL; |
| 247 | } |
| 248 | |
| 249 | sym = lookup_symbol (MDEBUG_EFI_SYMBOL_NAME, b, LABEL_DOMAIN, 0, NULL); |
| 250 | |
| 251 | /* If we never found a PDR for this function in symbol reading, then |
| 252 | examine prologues to find the information. */ |
| 253 | if (sym) |
| 254 | { |
| 255 | proc_desc = (struct mdebug_extra_func_info *) SYMBOL_VALUE (sym); |
| 256 | if (PROC_FRAME_REG (proc_desc) == -1) |
| 257 | return NULL; |
| 258 | else |
| 259 | return proc_desc; |
| 260 | } |
| 261 | else |
| 262 | return NULL; |
| 263 | } |
| 264 | |
| 265 | struct mips_frame_cache |
| 266 | { |
| 267 | CORE_ADDR base; |
| 268 | struct trad_frame_saved_reg *saved_regs; |
| 269 | }; |
| 270 | |
| 271 | static struct mips_frame_cache * |
| 272 | mips_mdebug_frame_cache (struct frame_info *next_frame, void **this_cache) |
| 273 | { |
| 274 | CORE_ADDR startaddr = 0; |
| 275 | struct mdebug_extra_func_info *proc_desc; |
| 276 | struct mips_frame_cache *cache; |
| 277 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
| 278 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 279 | /* r0 bit means kernel trap */ |
| 280 | int kernel_trap; |
| 281 | /* What registers have been saved? Bitmasks. */ |
| 282 | unsigned long gen_mask, float_mask; |
| 283 | |
| 284 | if ((*this_cache) != NULL) |
| 285 | return (*this_cache); |
| 286 | cache = FRAME_OBSTACK_ZALLOC (struct mips_frame_cache); |
| 287 | (*this_cache) = cache; |
| 288 | cache->saved_regs = trad_frame_alloc_saved_regs (next_frame); |
| 289 | |
| 290 | /* Get the mdebug proc descriptor. */ |
| 291 | proc_desc = non_heuristic_proc_desc (frame_pc_unwind (next_frame), |
| 292 | &startaddr); |
| 293 | /* Must be true. This is only called when the sniffer detected a |
| 294 | proc descriptor. */ |
| 295 | gdb_assert (proc_desc != NULL); |
| 296 | |
| 297 | /* Extract the frame's base. */ |
| 298 | cache->base = (frame_unwind_register_signed (next_frame, NUM_REGS + PROC_FRAME_REG (proc_desc)) |
| 299 | + PROC_FRAME_OFFSET (proc_desc)); |
| 300 | |
| 301 | kernel_trap = PROC_REG_MASK (proc_desc) & 1; |
| 302 | gen_mask = kernel_trap ? 0xFFFFFFFF : PROC_REG_MASK (proc_desc); |
| 303 | float_mask = kernel_trap ? 0xFFFFFFFF : PROC_FREG_MASK (proc_desc); |
| 304 | |
| 305 | /* Must be true. The in_prologue case is left for the heuristic |
| 306 | unwinder. This is always used on kernel traps. */ |
| 307 | gdb_assert (!in_prologue (frame_pc_unwind (next_frame), PROC_LOW_ADDR (proc_desc)) |
| 308 | || kernel_trap); |
| 309 | |
| 310 | /* Fill in the offsets for the registers which gen_mask says were |
| 311 | saved. */ |
| 312 | { |
| 313 | CORE_ADDR reg_position = (cache->base + PROC_REG_OFFSET (proc_desc)); |
| 314 | int ireg; |
| 315 | |
| 316 | for (ireg = MIPS_NUMREGS - 1; gen_mask; --ireg, gen_mask <<= 1) |
| 317 | if (gen_mask & 0x80000000) |
| 318 | { |
| 319 | cache->saved_regs[NUM_REGS + ireg].addr = reg_position; |
| 320 | reg_position -= mips_abi_regsize (gdbarch); |
| 321 | } |
| 322 | } |
| 323 | |
| 324 | /* Fill in the offsets for the registers which float_mask says were |
| 325 | saved. */ |
| 326 | { |
| 327 | CORE_ADDR reg_position = (cache->base |
| 328 | + PROC_FREG_OFFSET (proc_desc)); |
| 329 | int ireg; |
| 330 | /* Fill in the offsets for the float registers which float_mask |
| 331 | says were saved. */ |
| 332 | for (ireg = MIPS_NUMREGS - 1; float_mask; --ireg, float_mask <<= 1) |
| 333 | if (float_mask & 0x80000000) |
| 334 | { |
| 335 | if (mips_abi_regsize (gdbarch) == 4 |
| 336 | && TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
| 337 | { |
| 338 | /* On a big endian 32 bit ABI, floating point registers |
| 339 | are paired to form doubles such that the most |
| 340 | significant part is in $f[N+1] and the least |
| 341 | significant in $f[N] vis: $f[N+1] ||| $f[N]. The |
| 342 | registers are also spilled as a pair and stored as a |
| 343 | double. |
| 344 | |
| 345 | When little-endian the least significant part is |
| 346 | stored first leading to the memory order $f[N] and |
| 347 | then $f[N+1]. |
| 348 | |
| 349 | Unfortunately, when big-endian the most significant |
| 350 | part of the double is stored first, and the least |
| 351 | significant is stored second. This leads to the |
| 352 | registers being ordered in memory as firt $f[N+1] and |
| 353 | then $f[N]. |
| 354 | |
| 355 | For the big-endian case make certain that the |
| 356 | addresses point at the correct (swapped) locations |
| 357 | $f[N] and $f[N+1] pair (keep in mind that |
| 358 | reg_position is decremented each time through the |
| 359 | loop). */ |
| 360 | if ((ireg & 1)) |
| 361 | cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg] |
| 362 | .addr = reg_position - mips_abi_regsize (gdbarch); |
| 363 | else |
| 364 | cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg] |
| 365 | .addr = reg_position + mips_abi_regsize (gdbarch); |
| 366 | } |
| 367 | else |
| 368 | cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->fp0 + ireg] |
| 369 | .addr = reg_position; |
| 370 | reg_position -= mips_abi_regsize (gdbarch); |
| 371 | } |
| 372 | |
| 373 | cache->saved_regs[NUM_REGS + mips_regnum (current_gdbarch)->pc] |
| 374 | = cache->saved_regs[NUM_REGS + MIPS_RA_REGNUM]; |
| 375 | } |
| 376 | |
| 377 | /* SP_REGNUM, contains the value and not the address. */ |
| 378 | trad_frame_set_value (cache->saved_regs, NUM_REGS + MIPS_SP_REGNUM, cache->base); |
| 379 | |
| 380 | return (*this_cache); |
| 381 | } |
| 382 | |
| 383 | static void |
| 384 | mips_mdebug_frame_this_id (struct frame_info *next_frame, void **this_cache, |
| 385 | struct frame_id *this_id) |
| 386 | { |
| 387 | struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame, |
| 388 | this_cache); |
| 389 | (*this_id) = frame_id_build (info->base, frame_func_unwind (next_frame)); |
| 390 | } |
| 391 | |
| 392 | static void |
| 393 | mips_mdebug_frame_prev_register (struct frame_info *next_frame, |
| 394 | void **this_cache, |
| 395 | int regnum, int *optimizedp, |
| 396 | enum lval_type *lvalp, CORE_ADDR *addrp, |
| 397 | int *realnump, void *valuep) |
| 398 | { |
| 399 | struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame, |
| 400 | this_cache); |
| 401 | trad_frame_get_prev_register (next_frame, info->saved_regs, regnum, |
| 402 | optimizedp, lvalp, addrp, realnump, valuep); |
| 403 | } |
| 404 | |
| 405 | static const struct frame_unwind mips_mdebug_frame_unwind = |
| 406 | { |
| 407 | NORMAL_FRAME, |
| 408 | mips_mdebug_frame_this_id, |
| 409 | mips_mdebug_frame_prev_register |
| 410 | }; |
| 411 | |
| 412 | static const struct frame_unwind * |
| 413 | mips_mdebug_frame_sniffer (struct frame_info *next_frame) |
| 414 | { |
| 415 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
| 416 | CORE_ADDR startaddr = 0; |
| 417 | struct mdebug_extra_func_info *proc_desc; |
| 418 | int kernel_trap; |
| 419 | |
| 420 | /* Don't use this on MIPS16. */ |
| 421 | if (mips_pc_is_mips16 (pc)) |
| 422 | return NULL; |
| 423 | |
| 424 | /* Only use the mdebug frame unwinder on mdebug frames where all the |
| 425 | registers have been saved. Leave hard cases such as no mdebug or |
| 426 | in prologue for the heuristic unwinders. */ |
| 427 | |
| 428 | proc_desc = non_heuristic_proc_desc (pc, &startaddr); |
| 429 | if (proc_desc == NULL) |
| 430 | return NULL; |
| 431 | |
| 432 | /* Not sure exactly what kernel_trap means, but if it means the |
| 433 | kernel saves the registers without a prologue doing it, we better |
| 434 | not examine the prologue to see whether registers have been saved |
| 435 | yet. */ |
| 436 | kernel_trap = PROC_REG_MASK (proc_desc) & 1; |
| 437 | if (kernel_trap) |
| 438 | return &mips_mdebug_frame_unwind; |
| 439 | |
| 440 | /* In any frame other than the innermost or a frame interrupted by a |
| 441 | signal, we assume that all registers have been saved. This |
| 442 | assumes that all register saves in a function happen before the |
| 443 | first function call. */ |
| 444 | if (!in_prologue (pc, PROC_LOW_ADDR (proc_desc))) |
| 445 | return &mips_mdebug_frame_unwind; |
| 446 | |
| 447 | return NULL; |
| 448 | } |
| 449 | |
| 450 | static CORE_ADDR |
| 451 | mips_mdebug_frame_base_address (struct frame_info *next_frame, |
| 452 | void **this_cache) |
| 453 | { |
| 454 | struct mips_frame_cache *info = mips_mdebug_frame_cache (next_frame, |
| 455 | this_cache); |
| 456 | return info->base; |
| 457 | } |
| 458 | |
| 459 | static const struct frame_base mips_mdebug_frame_base = { |
| 460 | &mips_mdebug_frame_unwind, |
| 461 | mips_mdebug_frame_base_address, |
| 462 | mips_mdebug_frame_base_address, |
| 463 | mips_mdebug_frame_base_address |
| 464 | }; |
| 465 | |
| 466 | static const struct frame_base * |
| 467 | mips_mdebug_frame_base_sniffer (struct frame_info *next_frame) |
| 468 | { |
| 469 | if (mips_mdebug_frame_sniffer (next_frame) != NULL) |
| 470 | return &mips_mdebug_frame_base; |
| 471 | else |
| 472 | return NULL; |
| 473 | } |
| 474 | |
| 475 | void |
| 476 | mips_mdebug_append_sniffers (struct gdbarch *gdbarch) |
| 477 | { |
| 478 | frame_unwind_append_sniffer (gdbarch, mips_mdebug_frame_sniffer); |
| 479 | frame_base_append_sniffer (gdbarch, mips_mdebug_frame_base_sniffer); |
| 480 | } |
| 481 | |
| 482 | |
| 483 | extern void _initialize_mips_mdebug_tdep (void); |
| 484 | void |
| 485 | _initialize_mips_mdebug_tdep (void) |
| 486 | { |
| 487 | mips_pdr_data = register_objfile_data (); |
| 488 | } |