| 1 | /* Target-dependent mdebug code for the ALPHA architecture. |
| 2 | Copyright (C) 1993-2015 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 3 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, see <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include "defs.h" |
| 20 | #include "frame.h" |
| 21 | #include "frame-unwind.h" |
| 22 | #include "frame-base.h" |
| 23 | #include "symtab.h" |
| 24 | #include "gdbcore.h" |
| 25 | #include "block.h" |
| 26 | #include "trad-frame.h" |
| 27 | |
| 28 | #include "alpha-tdep.h" |
| 29 | #include "mdebugread.h" |
| 30 | |
| 31 | /* FIXME: Some of this code should perhaps be merged with mips. */ |
| 32 | |
| 33 | /* *INDENT-OFF* */ |
| 34 | /* Layout of a stack frame on the alpha: |
| 35 | |
| 36 | | | |
| 37 | pdr members: | 7th ... nth arg, | |
| 38 | | `pushed' by caller. | |
| 39 | | | |
| 40 | ----------------|-------------------------------|<-- old_sp == vfp |
| 41 | ^ ^ ^ ^ | | |
| 42 | | | | | | | |
| 43 | | |localoff | Copies of 1st .. 6th | |
| 44 | | | | | | argument if necessary. | |
| 45 | | | | v | | |
| 46 | | | | --- |-------------------------------|<-- LOCALS_ADDRESS |
| 47 | | | | | | |
| 48 | | | | | Locals and temporaries. | |
| 49 | | | | | | |
| 50 | | | | |-------------------------------| |
| 51 | | | | | | |
| 52 | |-fregoffset | Saved float registers. | |
| 53 | | | | | F9 | |
| 54 | | | | | . | |
| 55 | | | | | . | |
| 56 | | | | | F2 | |
| 57 | | | v | | |
| 58 | | | -------|-------------------------------| |
| 59 | | | | | |
| 60 | | | | Saved registers. | |
| 61 | | | | S6 | |
| 62 | |-regoffset | . | |
| 63 | | | | . | |
| 64 | | | | S0 | |
| 65 | | | | pdr.pcreg | |
| 66 | | v | | |
| 67 | | ----------|-------------------------------| |
| 68 | | | | |
| 69 | frameoffset | Argument build area, gets | |
| 70 | | | 7th ... nth arg for any | |
| 71 | | | called procedure. | |
| 72 | v | | |
| 73 | -------------|-------------------------------|<-- sp |
| 74 | | | |
| 75 | */ |
| 76 | /* *INDENT-ON* */ |
| 77 | |
| 78 | #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) |
| 79 | #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset) |
| 80 | #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg) |
| 81 | #define PROC_REG_MASK(proc) ((proc)->pdr.regmask) |
| 82 | #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask) |
| 83 | #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset) |
| 84 | #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset) |
| 85 | #define PROC_PC_REG(proc) ((proc)->pdr.pcreg) |
| 86 | #define PROC_LOCALOFF(proc) ((proc)->pdr.localoff) |
| 87 | \f |
| 88 | /* Locate the mdebug PDR for the given PC. Return null if one can't |
| 89 | be found; you'll have to fall back to other methods in that case. */ |
| 90 | |
| 91 | static struct mdebug_extra_func_info * |
| 92 | find_proc_desc (CORE_ADDR pc) |
| 93 | { |
| 94 | const struct block *b = block_for_pc (pc); |
| 95 | struct mdebug_extra_func_info *proc_desc = NULL; |
| 96 | struct symbol *sym = NULL; |
| 97 | const char *sh_name = NULL; |
| 98 | |
| 99 | if (b) |
| 100 | { |
| 101 | CORE_ADDR startaddr; |
| 102 | find_pc_partial_function (pc, &sh_name, &startaddr, NULL); |
| 103 | |
| 104 | if (startaddr > BLOCK_START (b)) |
| 105 | /* This is the "pathological" case referred to in a comment in |
| 106 | print_frame_info. It might be better to move this check into |
| 107 | symbol reading. */ |
| 108 | sym = NULL; |
| 109 | else |
| 110 | sym = lookup_symbol (MDEBUG_EFI_SYMBOL_NAME, b, LABEL_DOMAIN, |
| 111 | 0).symbol; |
| 112 | } |
| 113 | |
| 114 | if (sym) |
| 115 | { |
| 116 | proc_desc = (struct mdebug_extra_func_info *) SYMBOL_VALUE_BYTES (sym); |
| 117 | |
| 118 | /* Correct incorrect setjmp procedure descriptor from the library |
| 119 | to make backtrace through setjmp work. */ |
| 120 | if (proc_desc->pdr.pcreg == 0 |
| 121 | && strcmp (sh_name, "setjmp") == 0) |
| 122 | { |
| 123 | proc_desc->pdr.pcreg = ALPHA_RA_REGNUM; |
| 124 | proc_desc->pdr.regmask = 0x80000000; |
| 125 | proc_desc->pdr.regoffset = -4; |
| 126 | } |
| 127 | |
| 128 | /* If we never found a PDR for this function in symbol reading, |
| 129 | then examine prologues to find the information. */ |
| 130 | if (proc_desc->pdr.framereg == -1) |
| 131 | proc_desc = NULL; |
| 132 | } |
| 133 | |
| 134 | return proc_desc; |
| 135 | } |
| 136 | |
| 137 | /* Return a non-zero result if the function is frameless; zero otherwise. */ |
| 138 | |
| 139 | static int |
| 140 | alpha_mdebug_frameless (struct mdebug_extra_func_info *proc_desc) |
| 141 | { |
| 142 | return (PROC_FRAME_REG (proc_desc) == ALPHA_SP_REGNUM |
| 143 | && PROC_FRAME_OFFSET (proc_desc) == 0); |
| 144 | } |
| 145 | |
| 146 | /* This returns the PC of the first inst after the prologue. If we can't |
| 147 | find the prologue, then return 0. */ |
| 148 | |
| 149 | static CORE_ADDR |
| 150 | alpha_mdebug_after_prologue (CORE_ADDR pc, |
| 151 | struct mdebug_extra_func_info *proc_desc) |
| 152 | { |
| 153 | if (proc_desc) |
| 154 | { |
| 155 | /* If function is frameless, then we need to do it the hard way. I |
| 156 | strongly suspect that frameless always means prologueless... */ |
| 157 | if (alpha_mdebug_frameless (proc_desc)) |
| 158 | return 0; |
| 159 | } |
| 160 | |
| 161 | return alpha_after_prologue (pc); |
| 162 | } |
| 163 | |
| 164 | /* Return non-zero if we *might* be in a function prologue. Return zero |
| 165 | if we are definitively *not* in a function prologue. */ |
| 166 | |
| 167 | static int |
| 168 | alpha_mdebug_in_prologue (CORE_ADDR pc, |
| 169 | struct mdebug_extra_func_info *proc_desc) |
| 170 | { |
| 171 | CORE_ADDR after_prologue_pc = alpha_mdebug_after_prologue (pc, proc_desc); |
| 172 | return (after_prologue_pc == 0 || pc < after_prologue_pc); |
| 173 | } |
| 174 | |
| 175 | \f |
| 176 | /* Frame unwinder that reads mdebug PDRs. */ |
| 177 | |
| 178 | struct alpha_mdebug_unwind_cache |
| 179 | { |
| 180 | struct mdebug_extra_func_info *proc_desc; |
| 181 | CORE_ADDR vfp; |
| 182 | struct trad_frame_saved_reg *saved_regs; |
| 183 | }; |
| 184 | |
| 185 | /* Extract all of the information about the frame from PROC_DESC |
| 186 | and store the resulting register save locations in the structure. */ |
| 187 | |
| 188 | static struct alpha_mdebug_unwind_cache * |
| 189 | alpha_mdebug_frame_unwind_cache (struct frame_info *this_frame, |
| 190 | void **this_prologue_cache) |
| 191 | { |
| 192 | struct alpha_mdebug_unwind_cache *info; |
| 193 | struct mdebug_extra_func_info *proc_desc; |
| 194 | ULONGEST vfp; |
| 195 | CORE_ADDR pc, reg_position; |
| 196 | unsigned long mask; |
| 197 | int ireg, returnreg; |
| 198 | |
| 199 | if (*this_prologue_cache) |
| 200 | return *this_prologue_cache; |
| 201 | |
| 202 | info = FRAME_OBSTACK_ZALLOC (struct alpha_mdebug_unwind_cache); |
| 203 | *this_prologue_cache = info; |
| 204 | pc = get_frame_address_in_block (this_frame); |
| 205 | |
| 206 | /* ??? We don't seem to be able to cache the lookup of the PDR |
| 207 | from alpha_mdebug_frame_p. It'd be nice if we could change |
| 208 | the arguments to that function. Oh well. */ |
| 209 | proc_desc = find_proc_desc (pc); |
| 210 | info->proc_desc = proc_desc; |
| 211 | gdb_assert (proc_desc != NULL); |
| 212 | |
| 213 | info->saved_regs = trad_frame_alloc_saved_regs (this_frame); |
| 214 | |
| 215 | /* The VFP of the frame is at FRAME_REG+FRAME_OFFSET. */ |
| 216 | vfp = get_frame_register_unsigned (this_frame, PROC_FRAME_REG (proc_desc)); |
| 217 | vfp += PROC_FRAME_OFFSET (info->proc_desc); |
| 218 | info->vfp = vfp; |
| 219 | |
| 220 | /* Fill in the offsets for the registers which gen_mask says were saved. */ |
| 221 | |
| 222 | reg_position = vfp + PROC_REG_OFFSET (proc_desc); |
| 223 | mask = PROC_REG_MASK (proc_desc); |
| 224 | returnreg = PROC_PC_REG (proc_desc); |
| 225 | |
| 226 | /* Note that RA is always saved first, regardless of its actual |
| 227 | register number. */ |
| 228 | if (mask & (1 << returnreg)) |
| 229 | { |
| 230 | /* Clear bit for RA so we don't save it again later. */ |
| 231 | mask &= ~(1 << returnreg); |
| 232 | |
| 233 | info->saved_regs[returnreg].addr = reg_position; |
| 234 | reg_position += 8; |
| 235 | } |
| 236 | |
| 237 | for (ireg = 0; ireg <= 31; ++ireg) |
| 238 | if (mask & (1 << ireg)) |
| 239 | { |
| 240 | info->saved_regs[ireg].addr = reg_position; |
| 241 | reg_position += 8; |
| 242 | } |
| 243 | |
| 244 | reg_position = vfp + PROC_FREG_OFFSET (proc_desc); |
| 245 | mask = PROC_FREG_MASK (proc_desc); |
| 246 | |
| 247 | for (ireg = 0; ireg <= 31; ++ireg) |
| 248 | if (mask & (1 << ireg)) |
| 249 | { |
| 250 | info->saved_regs[ALPHA_FP0_REGNUM + ireg].addr = reg_position; |
| 251 | reg_position += 8; |
| 252 | } |
| 253 | |
| 254 | /* The stack pointer of the previous frame is computed by popping |
| 255 | the current stack frame. */ |
| 256 | if (!trad_frame_addr_p (info->saved_regs, ALPHA_SP_REGNUM)) |
| 257 | trad_frame_set_value (info->saved_regs, ALPHA_SP_REGNUM, vfp); |
| 258 | |
| 259 | return info; |
| 260 | } |
| 261 | |
| 262 | /* Given a GDB frame, determine the address of the calling function's |
| 263 | frame. This will be used to create a new GDB frame struct. */ |
| 264 | |
| 265 | static void |
| 266 | alpha_mdebug_frame_this_id (struct frame_info *this_frame, |
| 267 | void **this_prologue_cache, |
| 268 | struct frame_id *this_id) |
| 269 | { |
| 270 | struct alpha_mdebug_unwind_cache *info |
| 271 | = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache); |
| 272 | |
| 273 | *this_id = frame_id_build (info->vfp, get_frame_func (this_frame)); |
| 274 | } |
| 275 | |
| 276 | /* Retrieve the value of REGNUM in FRAME. Don't give up! */ |
| 277 | |
| 278 | static struct value * |
| 279 | alpha_mdebug_frame_prev_register (struct frame_info *this_frame, |
| 280 | void **this_prologue_cache, int regnum) |
| 281 | { |
| 282 | struct alpha_mdebug_unwind_cache *info |
| 283 | = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache); |
| 284 | |
| 285 | /* The PC of the previous frame is stored in the link register of |
| 286 | the current frame. Frob regnum so that we pull the value from |
| 287 | the correct place. */ |
| 288 | if (regnum == ALPHA_PC_REGNUM) |
| 289 | regnum = PROC_PC_REG (info->proc_desc); |
| 290 | |
| 291 | return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum); |
| 292 | } |
| 293 | |
| 294 | /* Return a non-zero result if the size of the stack frame exceeds the |
| 295 | maximum debuggable frame size (512 Kbytes); zero otherwise. */ |
| 296 | |
| 297 | static int |
| 298 | alpha_mdebug_max_frame_size_exceeded (struct mdebug_extra_func_info *proc_desc) |
| 299 | { |
| 300 | /* If frame offset is null, we can be in two cases: either the |
| 301 | function is frameless (the stack frame is null) or its |
| 302 | frame exceeds the maximum debuggable frame size (512 Kbytes). */ |
| 303 | |
| 304 | return (PROC_FRAME_OFFSET (proc_desc) == 0 |
| 305 | && !alpha_mdebug_frameless (proc_desc)); |
| 306 | } |
| 307 | |
| 308 | static int |
| 309 | alpha_mdebug_frame_sniffer (const struct frame_unwind *self, |
| 310 | struct frame_info *this_frame, |
| 311 | void **this_cache) |
| 312 | { |
| 313 | CORE_ADDR pc = get_frame_address_in_block (this_frame); |
| 314 | struct mdebug_extra_func_info *proc_desc; |
| 315 | |
| 316 | /* If this PC does not map to a PDR, then clearly this isn't an |
| 317 | mdebug frame. */ |
| 318 | proc_desc = find_proc_desc (pc); |
| 319 | if (proc_desc == NULL) |
| 320 | return 0; |
| 321 | |
| 322 | /* If we're in the prologue, the PDR for this frame is not yet valid. |
| 323 | Say no here and we'll fall back on the heuristic unwinder. */ |
| 324 | if (alpha_mdebug_in_prologue (pc, proc_desc)) |
| 325 | return 0; |
| 326 | |
| 327 | /* If the maximum debuggable frame size has been exceeded, the |
| 328 | proc desc is bogus. Fall back on the heuristic unwinder. */ |
| 329 | if (alpha_mdebug_max_frame_size_exceeded (proc_desc)) |
| 330 | return 0; |
| 331 | |
| 332 | return 1; |
| 333 | } |
| 334 | |
| 335 | static const struct frame_unwind alpha_mdebug_frame_unwind = { |
| 336 | NORMAL_FRAME, |
| 337 | default_frame_unwind_stop_reason, |
| 338 | alpha_mdebug_frame_this_id, |
| 339 | alpha_mdebug_frame_prev_register, |
| 340 | NULL, |
| 341 | alpha_mdebug_frame_sniffer |
| 342 | }; |
| 343 | |
| 344 | static CORE_ADDR |
| 345 | alpha_mdebug_frame_base_address (struct frame_info *this_frame, |
| 346 | void **this_prologue_cache) |
| 347 | { |
| 348 | struct alpha_mdebug_unwind_cache *info |
| 349 | = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache); |
| 350 | |
| 351 | return info->vfp; |
| 352 | } |
| 353 | |
| 354 | static CORE_ADDR |
| 355 | alpha_mdebug_frame_locals_address (struct frame_info *this_frame, |
| 356 | void **this_prologue_cache) |
| 357 | { |
| 358 | struct alpha_mdebug_unwind_cache *info |
| 359 | = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache); |
| 360 | |
| 361 | return info->vfp - PROC_LOCALOFF (info->proc_desc); |
| 362 | } |
| 363 | |
| 364 | static CORE_ADDR |
| 365 | alpha_mdebug_frame_args_address (struct frame_info *this_frame, |
| 366 | void **this_prologue_cache) |
| 367 | { |
| 368 | struct alpha_mdebug_unwind_cache *info |
| 369 | = alpha_mdebug_frame_unwind_cache (this_frame, this_prologue_cache); |
| 370 | |
| 371 | return info->vfp - ALPHA_NUM_ARG_REGS * 8; |
| 372 | } |
| 373 | |
| 374 | static const struct frame_base alpha_mdebug_frame_base = { |
| 375 | &alpha_mdebug_frame_unwind, |
| 376 | alpha_mdebug_frame_base_address, |
| 377 | alpha_mdebug_frame_locals_address, |
| 378 | alpha_mdebug_frame_args_address |
| 379 | }; |
| 380 | |
| 381 | static const struct frame_base * |
| 382 | alpha_mdebug_frame_base_sniffer (struct frame_info *this_frame) |
| 383 | { |
| 384 | CORE_ADDR pc = get_frame_address_in_block (this_frame); |
| 385 | struct mdebug_extra_func_info *proc_desc; |
| 386 | |
| 387 | /* If this PC does not map to a PDR, then clearly this isn't an |
| 388 | mdebug frame. */ |
| 389 | proc_desc = find_proc_desc (pc); |
| 390 | if (proc_desc == NULL) |
| 391 | return NULL; |
| 392 | |
| 393 | /* If the maximum debuggable frame size has been exceeded, the |
| 394 | proc desc is bogus. Fall back on the heuristic unwinder. */ |
| 395 | if (alpha_mdebug_max_frame_size_exceeded (proc_desc)) |
| 396 | return 0; |
| 397 | |
| 398 | return &alpha_mdebug_frame_base; |
| 399 | } |
| 400 | |
| 401 | \f |
| 402 | void |
| 403 | alpha_mdebug_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 404 | { |
| 405 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 406 | |
| 407 | frame_unwind_append_unwinder (gdbarch, &alpha_mdebug_frame_unwind); |
| 408 | frame_base_append_sniffer (gdbarch, alpha_mdebug_frame_base_sniffer); |
| 409 | } |