| 1 | /* Target-dependent mdebug code for the ALPHA architecture. |
| 2 | Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, |
| 3 | 2003, 2007 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., 51 Franklin Street, Fifth Floor, |
| 20 | Boston, MA 02110-1301, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "frame.h" |
| 24 | #include "frame-unwind.h" |
| 25 | #include "frame-base.h" |
| 26 | #include "symtab.h" |
| 27 | #include "gdbcore.h" |
| 28 | #include "block.h" |
| 29 | #include "gdb_assert.h" |
| 30 | |
| 31 | #include "alpha-tdep.h" |
| 32 | #include "mdebugread.h" |
| 33 | |
| 34 | /* FIXME: Some of this code should perhaps be merged with mips. */ |
| 35 | |
| 36 | /* *INDENT-OFF* */ |
| 37 | /* Layout of a stack frame on the alpha: |
| 38 | |
| 39 | | | |
| 40 | pdr members: | 7th ... nth arg, | |
| 41 | | `pushed' by caller. | |
| 42 | | | |
| 43 | ----------------|-------------------------------|<-- old_sp == vfp |
| 44 | ^ ^ ^ ^ | | |
| 45 | | | | | | | |
| 46 | | |localoff | Copies of 1st .. 6th | |
| 47 | | | | | | argument if necessary. | |
| 48 | | | | v | | |
| 49 | | | | --- |-------------------------------|<-- LOCALS_ADDRESS |
| 50 | | | | | | |
| 51 | | | | | Locals and temporaries. | |
| 52 | | | | | | |
| 53 | | | | |-------------------------------| |
| 54 | | | | | | |
| 55 | |-fregoffset | Saved float registers. | |
| 56 | | | | | F9 | |
| 57 | | | | | . | |
| 58 | | | | | . | |
| 59 | | | | | F2 | |
| 60 | | | v | | |
| 61 | | | -------|-------------------------------| |
| 62 | | | | | |
| 63 | | | | Saved registers. | |
| 64 | | | | S6 | |
| 65 | |-regoffset | . | |
| 66 | | | | . | |
| 67 | | | | S0 | |
| 68 | | | | pdr.pcreg | |
| 69 | | v | | |
| 70 | | ----------|-------------------------------| |
| 71 | | | | |
| 72 | frameoffset | Argument build area, gets | |
| 73 | | | 7th ... nth arg for any | |
| 74 | | | called procedure. | |
| 75 | v | | |
| 76 | -------------|-------------------------------|<-- sp |
| 77 | | | |
| 78 | */ |
| 79 | /* *INDENT-ON* */ |
| 80 | |
| 81 | #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) |
| 82 | #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset) |
| 83 | #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg) |
| 84 | #define PROC_REG_MASK(proc) ((proc)->pdr.regmask) |
| 85 | #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask) |
| 86 | #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset) |
| 87 | #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset) |
| 88 | #define PROC_PC_REG(proc) ((proc)->pdr.pcreg) |
| 89 | #define PROC_LOCALOFF(proc) ((proc)->pdr.localoff) |
| 90 | \f |
| 91 | /* Locate the mdebug PDR for the given PC. Return null if one can't |
| 92 | be found; you'll have to fall back to other methods in that case. */ |
| 93 | |
| 94 | static struct mdebug_extra_func_info * |
| 95 | find_proc_desc (CORE_ADDR pc) |
| 96 | { |
| 97 | struct block *b = block_for_pc (pc); |
| 98 | struct mdebug_extra_func_info *proc_desc = NULL; |
| 99 | struct symbol *sym = NULL; |
| 100 | |
| 101 | if (b) |
| 102 | { |
| 103 | CORE_ADDR startaddr; |
| 104 | find_pc_partial_function (pc, NULL, &startaddr, NULL); |
| 105 | |
| 106 | if (startaddr > BLOCK_START (b)) |
| 107 | /* This is the "pathological" case referred to in a comment in |
| 108 | print_frame_info. It might be better to move this check into |
| 109 | symbol reading. */ |
| 110 | sym = NULL; |
| 111 | else |
| 112 | sym = lookup_symbol (MDEBUG_EFI_SYMBOL_NAME, b, LABEL_DOMAIN, 0, NULL); |
| 113 | } |
| 114 | |
| 115 | if (sym) |
| 116 | { |
| 117 | proc_desc = (struct mdebug_extra_func_info *) SYMBOL_VALUE (sym); |
| 118 | |
| 119 | /* If we never found a PDR for this function in symbol reading, |
| 120 | then examine prologues to find the information. */ |
| 121 | if (proc_desc->pdr.framereg == -1) |
| 122 | proc_desc = NULL; |
| 123 | } |
| 124 | |
| 125 | return proc_desc; |
| 126 | } |
| 127 | |
| 128 | /* This returns the PC of the first inst after the prologue. If we can't |
| 129 | find the prologue, then return 0. */ |
| 130 | |
| 131 | static CORE_ADDR |
| 132 | alpha_mdebug_after_prologue (CORE_ADDR pc, struct mdebug_extra_func_info *proc_desc) |
| 133 | { |
| 134 | if (proc_desc) |
| 135 | { |
| 136 | /* If function is frameless, then we need to do it the hard way. I |
| 137 | strongly suspect that frameless always means prologueless... */ |
| 138 | if (PROC_FRAME_REG (proc_desc) == ALPHA_SP_REGNUM |
| 139 | && PROC_FRAME_OFFSET (proc_desc) == 0) |
| 140 | return 0; |
| 141 | } |
| 142 | |
| 143 | return alpha_after_prologue (pc); |
| 144 | } |
| 145 | |
| 146 | /* Return non-zero if we *might* be in a function prologue. Return zero |
| 147 | if we are definitively *not* in a function prologue. */ |
| 148 | |
| 149 | static int |
| 150 | alpha_mdebug_in_prologue (CORE_ADDR pc, struct mdebug_extra_func_info *proc_desc) |
| 151 | { |
| 152 | CORE_ADDR after_prologue_pc = alpha_mdebug_after_prologue (pc, proc_desc); |
| 153 | return (after_prologue_pc == 0 || pc < after_prologue_pc); |
| 154 | } |
| 155 | |
| 156 | \f |
| 157 | /* Frame unwinder that reads mdebug PDRs. */ |
| 158 | |
| 159 | struct alpha_mdebug_unwind_cache |
| 160 | { |
| 161 | struct mdebug_extra_func_info *proc_desc; |
| 162 | CORE_ADDR vfp; |
| 163 | CORE_ADDR *saved_regs; |
| 164 | }; |
| 165 | |
| 166 | /* Extract all of the information about the frame from PROC_DESC |
| 167 | and store the resulting register save locations in the structure. */ |
| 168 | |
| 169 | static struct alpha_mdebug_unwind_cache * |
| 170 | alpha_mdebug_frame_unwind_cache (struct frame_info *next_frame, |
| 171 | void **this_prologue_cache) |
| 172 | { |
| 173 | struct alpha_mdebug_unwind_cache *info; |
| 174 | struct mdebug_extra_func_info *proc_desc; |
| 175 | ULONGEST vfp; |
| 176 | CORE_ADDR pc, reg_position; |
| 177 | unsigned long mask; |
| 178 | int ireg, returnreg; |
| 179 | |
| 180 | if (*this_prologue_cache) |
| 181 | return *this_prologue_cache; |
| 182 | |
| 183 | info = FRAME_OBSTACK_ZALLOC (struct alpha_mdebug_unwind_cache); |
| 184 | *this_prologue_cache = info; |
| 185 | pc = frame_pc_unwind (next_frame); |
| 186 | |
| 187 | /* ??? We don't seem to be able to cache the lookup of the PDR |
| 188 | from alpha_mdebug_frame_p. It'd be nice if we could change |
| 189 | the arguments to that function. Oh well. */ |
| 190 | proc_desc = find_proc_desc (pc); |
| 191 | info->proc_desc = proc_desc; |
| 192 | gdb_assert (proc_desc != NULL); |
| 193 | |
| 194 | info->saved_regs = frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS); |
| 195 | |
| 196 | /* The VFP of the frame is at FRAME_REG+FRAME_OFFSET. */ |
| 197 | frame_unwind_unsigned_register (next_frame, PROC_FRAME_REG (proc_desc), &vfp); |
| 198 | vfp += PROC_FRAME_OFFSET (info->proc_desc); |
| 199 | info->vfp = vfp; |
| 200 | |
| 201 | /* Fill in the offsets for the registers which gen_mask says were saved. */ |
| 202 | |
| 203 | reg_position = vfp + PROC_REG_OFFSET (proc_desc); |
| 204 | mask = PROC_REG_MASK (proc_desc); |
| 205 | returnreg = PROC_PC_REG (proc_desc); |
| 206 | |
| 207 | /* Note that RA is always saved first, regardless of its actual |
| 208 | register number. */ |
| 209 | if (mask & (1 << returnreg)) |
| 210 | { |
| 211 | /* Clear bit for RA so we don't save it again later. */ |
| 212 | mask &= ~(1 << returnreg); |
| 213 | |
| 214 | info->saved_regs[returnreg] = reg_position; |
| 215 | reg_position += 8; |
| 216 | } |
| 217 | |
| 218 | for (ireg = 0; ireg <= 31; ++ireg) |
| 219 | if (mask & (1 << ireg)) |
| 220 | { |
| 221 | info->saved_regs[ireg] = reg_position; |
| 222 | reg_position += 8; |
| 223 | } |
| 224 | |
| 225 | reg_position = vfp + PROC_FREG_OFFSET (proc_desc); |
| 226 | mask = PROC_FREG_MASK (proc_desc); |
| 227 | |
| 228 | for (ireg = 0; ireg <= 31; ++ireg) |
| 229 | if (mask & (1 << ireg)) |
| 230 | { |
| 231 | info->saved_regs[ALPHA_FP0_REGNUM + ireg] = reg_position; |
| 232 | reg_position += 8; |
| 233 | } |
| 234 | |
| 235 | return info; |
| 236 | } |
| 237 | |
| 238 | /* Given a GDB frame, determine the address of the calling function's |
| 239 | frame. This will be used to create a new GDB frame struct. */ |
| 240 | |
| 241 | static void |
| 242 | alpha_mdebug_frame_this_id (struct frame_info *next_frame, |
| 243 | void **this_prologue_cache, |
| 244 | struct frame_id *this_id) |
| 245 | { |
| 246 | struct alpha_mdebug_unwind_cache *info |
| 247 | = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache); |
| 248 | |
| 249 | *this_id = frame_id_build (info->vfp, |
| 250 | frame_func_unwind (next_frame, NORMAL_FRAME)); |
| 251 | } |
| 252 | |
| 253 | /* Retrieve the value of REGNUM in FRAME. Don't give up! */ |
| 254 | |
| 255 | static void |
| 256 | alpha_mdebug_frame_prev_register (struct frame_info *next_frame, |
| 257 | void **this_prologue_cache, |
| 258 | int regnum, int *optimizedp, |
| 259 | enum lval_type *lvalp, CORE_ADDR *addrp, |
| 260 | int *realnump, gdb_byte *bufferp) |
| 261 | { |
| 262 | struct alpha_mdebug_unwind_cache *info |
| 263 | = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache); |
| 264 | |
| 265 | /* The PC of the previous frame is stored in the link register of |
| 266 | the current frame. Frob regnum so that we pull the value from |
| 267 | the correct place. */ |
| 268 | if (regnum == ALPHA_PC_REGNUM) |
| 269 | regnum = PROC_PC_REG (info->proc_desc); |
| 270 | |
| 271 | /* For all registers known to be saved in the current frame, |
| 272 | do the obvious and pull the value out. */ |
| 273 | if (info->saved_regs[regnum]) |
| 274 | { |
| 275 | *optimizedp = 0; |
| 276 | *lvalp = lval_memory; |
| 277 | *addrp = info->saved_regs[regnum]; |
| 278 | *realnump = -1; |
| 279 | if (bufferp != NULL) |
| 280 | get_frame_memory (next_frame, *addrp, bufferp, ALPHA_REGISTER_SIZE); |
| 281 | return; |
| 282 | } |
| 283 | |
| 284 | /* The stack pointer of the previous frame is computed by popping |
| 285 | the current stack frame. */ |
| 286 | if (regnum == ALPHA_SP_REGNUM) |
| 287 | { |
| 288 | *optimizedp = 0; |
| 289 | *lvalp = not_lval; |
| 290 | *addrp = 0; |
| 291 | *realnump = -1; |
| 292 | if (bufferp != NULL) |
| 293 | store_unsigned_integer (bufferp, ALPHA_REGISTER_SIZE, info->vfp); |
| 294 | return; |
| 295 | } |
| 296 | |
| 297 | /* Otherwise assume the next frame has the same register value. */ |
| 298 | *optimizedp = 0; |
| 299 | *lvalp = lval_register; |
| 300 | *addrp = 0; |
| 301 | *realnump = regnum; |
| 302 | if (bufferp) |
| 303 | frame_unwind_register (next_frame, *realnump, bufferp); |
| 304 | } |
| 305 | |
| 306 | static const struct frame_unwind alpha_mdebug_frame_unwind = { |
| 307 | NORMAL_FRAME, |
| 308 | alpha_mdebug_frame_this_id, |
| 309 | alpha_mdebug_frame_prev_register |
| 310 | }; |
| 311 | |
| 312 | const struct frame_unwind * |
| 313 | alpha_mdebug_frame_sniffer (struct frame_info *next_frame) |
| 314 | { |
| 315 | CORE_ADDR pc = frame_unwind_address_in_block (next_frame, NORMAL_FRAME); |
| 316 | struct mdebug_extra_func_info *proc_desc; |
| 317 | |
| 318 | /* If this PC does not map to a PDR, then clearly this isn't an |
| 319 | mdebug frame. */ |
| 320 | proc_desc = find_proc_desc (pc); |
| 321 | if (proc_desc == NULL) |
| 322 | return NULL; |
| 323 | |
| 324 | /* If we're in the prologue, the PDR for this frame is not yet valid. |
| 325 | Say no here and we'll fall back on the heuristic unwinder. */ |
| 326 | if (alpha_mdebug_in_prologue (pc, proc_desc)) |
| 327 | return NULL; |
| 328 | |
| 329 | return &alpha_mdebug_frame_unwind; |
| 330 | } |
| 331 | |
| 332 | static CORE_ADDR |
| 333 | alpha_mdebug_frame_base_address (struct frame_info *next_frame, |
| 334 | void **this_prologue_cache) |
| 335 | { |
| 336 | struct alpha_mdebug_unwind_cache *info |
| 337 | = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache); |
| 338 | |
| 339 | return info->vfp; |
| 340 | } |
| 341 | |
| 342 | static CORE_ADDR |
| 343 | alpha_mdebug_frame_locals_address (struct frame_info *next_frame, |
| 344 | void **this_prologue_cache) |
| 345 | { |
| 346 | struct alpha_mdebug_unwind_cache *info |
| 347 | = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache); |
| 348 | |
| 349 | return info->vfp - PROC_LOCALOFF (info->proc_desc); |
| 350 | } |
| 351 | |
| 352 | static CORE_ADDR |
| 353 | alpha_mdebug_frame_args_address (struct frame_info *next_frame, |
| 354 | void **this_prologue_cache) |
| 355 | { |
| 356 | struct alpha_mdebug_unwind_cache *info |
| 357 | = alpha_mdebug_frame_unwind_cache (next_frame, this_prologue_cache); |
| 358 | |
| 359 | return info->vfp - ALPHA_NUM_ARG_REGS * 8; |
| 360 | } |
| 361 | |
| 362 | static const struct frame_base alpha_mdebug_frame_base = { |
| 363 | &alpha_mdebug_frame_unwind, |
| 364 | alpha_mdebug_frame_base_address, |
| 365 | alpha_mdebug_frame_locals_address, |
| 366 | alpha_mdebug_frame_args_address |
| 367 | }; |
| 368 | |
| 369 | static const struct frame_base * |
| 370 | alpha_mdebug_frame_base_sniffer (struct frame_info *next_frame) |
| 371 | { |
| 372 | CORE_ADDR pc = frame_unwind_address_in_block (next_frame, NORMAL_FRAME); |
| 373 | struct mdebug_extra_func_info *proc_desc; |
| 374 | |
| 375 | /* If this PC does not map to a PDR, then clearly this isn't an |
| 376 | mdebug frame. */ |
| 377 | proc_desc = find_proc_desc (pc); |
| 378 | if (proc_desc == NULL) |
| 379 | return NULL; |
| 380 | |
| 381 | return &alpha_mdebug_frame_base; |
| 382 | } |
| 383 | |
| 384 | \f |
| 385 | void |
| 386 | alpha_mdebug_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 387 | { |
| 388 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 389 | |
| 390 | frame_unwind_append_sniffer (gdbarch, alpha_mdebug_frame_sniffer); |
| 391 | frame_base_append_sniffer (gdbarch, alpha_mdebug_frame_base_sniffer); |
| 392 | } |