| 1 | /* Target-dependent code for GDB, the GNU debugger. |
| 2 | Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997 |
| 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, Boston, MA 02111-1307, USA. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "frame.h" |
| 23 | #include "inferior.h" |
| 24 | #include "symtab.h" |
| 25 | #include "target.h" |
| 26 | #include "gdbcore.h" |
| 27 | #include "symfile.h" |
| 28 | #include "objfiles.h" |
| 29 | #include "xcoffsolib.h" |
| 30 | |
| 31 | extern int errno; |
| 32 | |
| 33 | /* Breakpoint shadows for the single step instructions will be kept here. */ |
| 34 | |
| 35 | static struct sstep_breaks { |
| 36 | /* Address, or 0 if this is not in use. */ |
| 37 | CORE_ADDR address; |
| 38 | /* Shadow contents. */ |
| 39 | char data[4]; |
| 40 | } stepBreaks[2]; |
| 41 | |
| 42 | /* Hook for determining the TOC address when calling functions in the |
| 43 | inferior under AIX. The initialization code in rs6000-nat.c sets |
| 44 | this hook to point to find_toc_address. */ |
| 45 | |
| 46 | CORE_ADDR (*find_toc_address_hook) PARAMS ((CORE_ADDR)) = NULL; |
| 47 | |
| 48 | /* Static function prototypes */ |
| 49 | |
| 50 | static CORE_ADDR branch_dest PARAMS ((int opcode, int instr, CORE_ADDR pc, |
| 51 | CORE_ADDR safety)); |
| 52 | |
| 53 | static void frame_get_saved_regs PARAMS ((struct frame_info *fi, |
| 54 | struct rs6000_framedata *fdatap)); |
| 55 | |
| 56 | static void pop_dummy_frame PARAMS ((void)); |
| 57 | |
| 58 | static CORE_ADDR frame_initial_stack_address PARAMS ((struct frame_info *)); |
| 59 | |
| 60 | /* Fill in fi->saved_regs */ |
| 61 | |
| 62 | struct frame_extra_info |
| 63 | { |
| 64 | /* Functions calling alloca() change the value of the stack |
| 65 | pointer. We need to use initial stack pointer (which is saved in |
| 66 | r31 by gcc) in such cases. If a compiler emits traceback table, |
| 67 | then we should use the alloca register specified in traceback |
| 68 | table. FIXME. */ |
| 69 | CORE_ADDR initial_sp; /* initial stack pointer. */ \ |
| 70 | }; |
| 71 | |
| 72 | void |
| 73 | rs6000_init_extra_frame_info (fromleaf, fi) |
| 74 | int fromleaf; |
| 75 | struct frame_info *fi; |
| 76 | { |
| 77 | fi->extra_info = (struct frame_extra_info*) |
| 78 | frame_obstack_alloc (sizeof (struct frame_extra_info)); |
| 79 | fi->extra_info->initial_sp = 0; |
| 80 | if (fi->next != (CORE_ADDR) 0 |
| 81 | && fi->pc < TEXT_SEGMENT_BASE) |
| 82 | /* We're in get_prev_frame_info */ |
| 83 | /* and this is a special signal frame. */ |
| 84 | /* (fi->pc will be some low address in the kernel, */ |
| 85 | /* to which the signal handler returns). */ |
| 86 | fi->signal_handler_caller = 1; |
| 87 | } |
| 88 | |
| 89 | |
| 90 | void |
| 91 | rs6000_frame_init_saved_regs (fi) |
| 92 | struct frame_info *fi; |
| 93 | { |
| 94 | frame_get_saved_regs (fi, NULL); |
| 95 | } |
| 96 | |
| 97 | CORE_ADDR |
| 98 | rs6000_frame_args_address (fi) |
| 99 | struct frame_info *fi; |
| 100 | { |
| 101 | if (fi->extra_info->initial_sp != 0) |
| 102 | return fi->extra_info->initial_sp; |
| 103 | else |
| 104 | return frame_initial_stack_address (fi); |
| 105 | } |
| 106 | |
| 107 | |
| 108 | /* Calculate the destination of a branch/jump. Return -1 if not a branch. */ |
| 109 | |
| 110 | static CORE_ADDR |
| 111 | branch_dest (opcode, instr, pc, safety) |
| 112 | int opcode; |
| 113 | int instr; |
| 114 | CORE_ADDR pc; |
| 115 | CORE_ADDR safety; |
| 116 | { |
| 117 | CORE_ADDR dest; |
| 118 | int immediate; |
| 119 | int absolute; |
| 120 | int ext_op; |
| 121 | |
| 122 | absolute = (int) ((instr >> 1) & 1); |
| 123 | |
| 124 | switch (opcode) { |
| 125 | case 18 : |
| 126 | immediate = ((instr & ~3) << 6) >> 6; /* br unconditional */ |
| 127 | if (absolute) |
| 128 | dest = immediate; |
| 129 | else |
| 130 | dest = pc + immediate; |
| 131 | break; |
| 132 | |
| 133 | case 16 : |
| 134 | immediate = ((instr & ~3) << 16) >> 16; /* br conditional */ |
| 135 | if (absolute) |
| 136 | dest = immediate; |
| 137 | else |
| 138 | dest = pc + immediate; |
| 139 | break; |
| 140 | |
| 141 | case 19 : |
| 142 | ext_op = (instr>>1) & 0x3ff; |
| 143 | |
| 144 | if (ext_op == 16) /* br conditional register */ |
| 145 | { |
| 146 | dest = read_register (LR_REGNUM) & ~3; |
| 147 | |
| 148 | /* If we are about to return from a signal handler, dest is |
| 149 | something like 0x3c90. The current frame is a signal handler |
| 150 | caller frame, upon completion of the sigreturn system call |
| 151 | execution will return to the saved PC in the frame. */ |
| 152 | if (dest < TEXT_SEGMENT_BASE) |
| 153 | { |
| 154 | struct frame_info *fi; |
| 155 | |
| 156 | fi = get_current_frame (); |
| 157 | if (fi != NULL) |
| 158 | dest = read_memory_integer (fi->frame + SIG_FRAME_PC_OFFSET, |
| 159 | 4); |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | else if (ext_op == 528) /* br cond to count reg */ |
| 164 | { |
| 165 | dest = read_register (CTR_REGNUM) & ~3; |
| 166 | |
| 167 | /* If we are about to execute a system call, dest is something |
| 168 | like 0x22fc or 0x3b00. Upon completion the system call |
| 169 | will return to the address in the link register. */ |
| 170 | if (dest < TEXT_SEGMENT_BASE) |
| 171 | dest = read_register (LR_REGNUM) & ~3; |
| 172 | } |
| 173 | else return -1; |
| 174 | break; |
| 175 | |
| 176 | default: return -1; |
| 177 | } |
| 178 | return (dest < TEXT_SEGMENT_BASE) ? safety : dest; |
| 179 | } |
| 180 | |
| 181 | |
| 182 | /* Sequence of bytes for breakpoint instruction. */ |
| 183 | |
| 184 | #define BIG_BREAKPOINT { 0x7d, 0x82, 0x10, 0x08 } |
| 185 | #define LITTLE_BREAKPOINT { 0x08, 0x10, 0x82, 0x7d } |
| 186 | |
| 187 | unsigned char * |
| 188 | rs6000_breakpoint_from_pc (bp_addr, bp_size) |
| 189 | CORE_ADDR *bp_addr; |
| 190 | int *bp_size; |
| 191 | { |
| 192 | static unsigned char big_breakpoint[] = BIG_BREAKPOINT; |
| 193 | static unsigned char little_breakpoint[] = LITTLE_BREAKPOINT; |
| 194 | *bp_size = 4; |
| 195 | if (TARGET_BYTE_ORDER == BIG_ENDIAN) |
| 196 | return big_breakpoint; |
| 197 | else |
| 198 | return little_breakpoint; |
| 199 | } |
| 200 | |
| 201 | |
| 202 | /* AIX does not support PT_STEP. Simulate it. */ |
| 203 | |
| 204 | void |
| 205 | rs6000_software_single_step (signal, insert_breakpoints_p) |
| 206 | enum target_signal signal; |
| 207 | int insert_breakpoints_p; |
| 208 | { |
| 209 | #define INSNLEN(OPCODE) 4 |
| 210 | |
| 211 | static char le_breakp[] = LITTLE_BREAKPOINT; |
| 212 | static char be_breakp[] = BIG_BREAKPOINT; |
| 213 | char *breakp = TARGET_BYTE_ORDER == BIG_ENDIAN ? be_breakp : le_breakp; |
| 214 | int ii, insn; |
| 215 | CORE_ADDR loc; |
| 216 | CORE_ADDR breaks[2]; |
| 217 | int opcode; |
| 218 | |
| 219 | if (insert_breakpoints_p) { |
| 220 | |
| 221 | loc = read_pc (); |
| 222 | |
| 223 | insn = read_memory_integer (loc, 4); |
| 224 | |
| 225 | breaks[0] = loc + INSNLEN(insn); |
| 226 | opcode = insn >> 26; |
| 227 | breaks[1] = branch_dest (opcode, insn, loc, breaks[0]); |
| 228 | |
| 229 | /* Don't put two breakpoints on the same address. */ |
| 230 | if (breaks[1] == breaks[0]) |
| 231 | breaks[1] = -1; |
| 232 | |
| 233 | stepBreaks[1].address = 0; |
| 234 | |
| 235 | for (ii=0; ii < 2; ++ii) { |
| 236 | |
| 237 | /* ignore invalid breakpoint. */ |
| 238 | if ( breaks[ii] == -1) |
| 239 | continue; |
| 240 | |
| 241 | read_memory (breaks[ii], stepBreaks[ii].data, 4); |
| 242 | |
| 243 | write_memory (breaks[ii], breakp, 4); |
| 244 | stepBreaks[ii].address = breaks[ii]; |
| 245 | } |
| 246 | |
| 247 | } else { |
| 248 | |
| 249 | /* remove step breakpoints. */ |
| 250 | for (ii=0; ii < 2; ++ii) |
| 251 | if (stepBreaks[ii].address != 0) |
| 252 | write_memory |
| 253 | (stepBreaks[ii].address, stepBreaks[ii].data, 4); |
| 254 | |
| 255 | } |
| 256 | errno = 0; /* FIXME, don't ignore errors! */ |
| 257 | /* What errors? {read,write}_memory call error(). */ |
| 258 | } |
| 259 | |
| 260 | |
| 261 | /* return pc value after skipping a function prologue and also return |
| 262 | information about a function frame. |
| 263 | |
| 264 | in struct rs6000_framedata fdata: |
| 265 | - frameless is TRUE, if function does not have a frame. |
| 266 | - nosavedpc is TRUE, if function does not save %pc value in its frame. |
| 267 | - offset is the initial size of this stack frame --- the amount by |
| 268 | which we decrement the sp to allocate the frame. |
| 269 | - saved_gpr is the number of the first saved gpr. |
| 270 | - saved_fpr is the number of the first saved fpr. |
| 271 | - alloca_reg is the number of the register used for alloca() handling. |
| 272 | Otherwise -1. |
| 273 | - gpr_offset is the offset of the first saved gpr from the previous frame. |
| 274 | - fpr_offset is the offset of the first saved fpr from the previous frame. |
| 275 | - lr_offset is the offset of the saved lr |
| 276 | - cr_offset is the offset of the saved cr |
| 277 | */ |
| 278 | |
| 279 | #define SIGNED_SHORT(x) \ |
| 280 | ((sizeof (short) == 2) \ |
| 281 | ? ((int)(short)(x)) \ |
| 282 | : ((int)((((x) & 0xffff) ^ 0x8000) - 0x8000))) |
| 283 | |
| 284 | #define GET_SRC_REG(x) (((x) >> 21) & 0x1f) |
| 285 | |
| 286 | CORE_ADDR |
| 287 | skip_prologue (pc, fdata) |
| 288 | CORE_ADDR pc; |
| 289 | struct rs6000_framedata *fdata; |
| 290 | { |
| 291 | CORE_ADDR orig_pc = pc; |
| 292 | char buf[4]; |
| 293 | unsigned long op; |
| 294 | long offset = 0; |
| 295 | int lr_reg = 0; |
| 296 | int cr_reg = 0; |
| 297 | int reg; |
| 298 | int framep = 0; |
| 299 | int minimal_toc_loaded = 0; |
| 300 | static struct rs6000_framedata zero_frame; |
| 301 | |
| 302 | *fdata = zero_frame; |
| 303 | fdata->saved_gpr = -1; |
| 304 | fdata->saved_fpr = -1; |
| 305 | fdata->alloca_reg = -1; |
| 306 | fdata->frameless = 1; |
| 307 | fdata->nosavedpc = 1; |
| 308 | |
| 309 | if (target_read_memory (pc, buf, 4)) |
| 310 | return pc; /* Can't access it -- assume no prologue. */ |
| 311 | |
| 312 | /* Assume that subsequent fetches can fail with low probability. */ |
| 313 | pc -= 4; |
| 314 | for (;;) |
| 315 | { |
| 316 | pc += 4; |
| 317 | op = read_memory_integer (pc, 4); |
| 318 | |
| 319 | if ((op & 0xfc1fffff) == 0x7c0802a6) { /* mflr Rx */ |
| 320 | lr_reg = (op & 0x03e00000) | 0x90010000; |
| 321 | continue; |
| 322 | |
| 323 | } else if ((op & 0xfc1fffff) == 0x7c000026) { /* mfcr Rx */ |
| 324 | cr_reg = (op & 0x03e00000) | 0x90010000; |
| 325 | continue; |
| 326 | |
| 327 | } else if ((op & 0xfc1f0000) == 0xd8010000) { /* stfd Rx,NUM(r1) */ |
| 328 | reg = GET_SRC_REG (op); |
| 329 | if (fdata->saved_fpr == -1 || fdata->saved_fpr > reg) { |
| 330 | fdata->saved_fpr = reg; |
| 331 | fdata->fpr_offset = SIGNED_SHORT (op) + offset; |
| 332 | } |
| 333 | continue; |
| 334 | |
| 335 | } else if (((op & 0xfc1f0000) == 0xbc010000) || /* stm Rx, NUM(r1) */ |
| 336 | ((op & 0xfc1f0000) == 0x90010000 && /* st rx,NUM(r1), |
| 337 | rx >= r13 */ |
| 338 | (op & 0x03e00000) >= 0x01a00000)) { |
| 339 | |
| 340 | reg = GET_SRC_REG (op); |
| 341 | if (fdata->saved_gpr == -1 || fdata->saved_gpr > reg) { |
| 342 | fdata->saved_gpr = reg; |
| 343 | fdata->gpr_offset = SIGNED_SHORT (op) + offset; |
| 344 | } |
| 345 | continue; |
| 346 | |
| 347 | } else if ((op & 0xffff0000) == 0x3c000000) { /* addis 0,0,NUM, used |
| 348 | for >= 32k frames */ |
| 349 | fdata->offset = (op & 0x0000ffff) << 16; |
| 350 | fdata->frameless = 0; |
| 351 | continue; |
| 352 | |
| 353 | } else if ((op & 0xffff0000) == 0x60000000) { /* ori 0,0,NUM, 2nd ha |
| 354 | lf of >= 32k frames */ |
| 355 | fdata->offset |= (op & 0x0000ffff); |
| 356 | fdata->frameless = 0; |
| 357 | continue; |
| 358 | |
| 359 | } else if ((op & 0xffff0000) == lr_reg) { /* st Rx,NUM(r1) |
| 360 | where Rx == lr */ |
| 361 | fdata->lr_offset = SIGNED_SHORT (op) + offset; |
| 362 | fdata->nosavedpc = 0; |
| 363 | lr_reg = 0; |
| 364 | continue; |
| 365 | |
| 366 | } else if ((op & 0xffff0000) == cr_reg) { /* st Rx,NUM(r1) |
| 367 | where Rx == cr */ |
| 368 | fdata->cr_offset = SIGNED_SHORT (op) + offset; |
| 369 | cr_reg = 0; |
| 370 | continue; |
| 371 | |
| 372 | } else if (op == 0x48000005) { /* bl .+4 used in |
| 373 | -mrelocatable */ |
| 374 | continue; |
| 375 | |
| 376 | } else if (op == 0x48000004) { /* b .+4 (xlc) */ |
| 377 | break; |
| 378 | |
| 379 | } else if (((op & 0xffff0000) == 0x801e0000 || /* lwz 0,NUM(r30), used |
| 380 | in V.4 -mrelocatable */ |
| 381 | op == 0x7fc0f214) && /* add r30,r0,r30, used |
| 382 | in V.4 -mrelocatable */ |
| 383 | lr_reg == 0x901e0000) { |
| 384 | continue; |
| 385 | |
| 386 | } else if ((op & 0xffff0000) == 0x3fc00000 || /* addis 30,0,foo@ha, used |
| 387 | in V.4 -mminimal-toc */ |
| 388 | (op & 0xffff0000) == 0x3bde0000) { /* addi 30,30,foo@l */ |
| 389 | continue; |
| 390 | |
| 391 | } else if ((op & 0xfc000000) == 0x48000000) { /* bl foo, |
| 392 | to save fprs??? */ |
| 393 | |
| 394 | fdata->frameless = 0; |
| 395 | /* Don't skip over the subroutine call if it is not within the first |
| 396 | three instructions of the prologue. */ |
| 397 | if ((pc - orig_pc) > 8) |
| 398 | break; |
| 399 | |
| 400 | op = read_memory_integer (pc+4, 4); |
| 401 | |
| 402 | /* At this point, make sure this is not a trampoline function |
| 403 | (a function that simply calls another functions, and nothing else). |
| 404 | If the next is not a nop, this branch was part of the function |
| 405 | prologue. */ |
| 406 | |
| 407 | if (op == 0x4def7b82 || op == 0) /* crorc 15, 15, 15 */ |
| 408 | break; /* don't skip over |
| 409 | this branch */ |
| 410 | continue; |
| 411 | |
| 412 | /* update stack pointer */ |
| 413 | } else if ((op & 0xffff0000) == 0x94210000) { /* stu r1,NUM(r1) */ |
| 414 | fdata->frameless = 0; |
| 415 | fdata->offset = SIGNED_SHORT (op); |
| 416 | offset = fdata->offset; |
| 417 | continue; |
| 418 | |
| 419 | } else if (op == 0x7c21016e) { /* stwux 1,1,0 */ |
| 420 | fdata->frameless = 0; |
| 421 | offset = fdata->offset; |
| 422 | continue; |
| 423 | |
| 424 | /* Load up minimal toc pointer */ |
| 425 | } else if ((op >> 22) == 0x20f |
| 426 | && ! minimal_toc_loaded) { /* l r31,... or l r30,... */ |
| 427 | minimal_toc_loaded = 1; |
| 428 | continue; |
| 429 | |
| 430 | /* store parameters in stack */ |
| 431 | } else if ((op & 0xfc1f0000) == 0x90010000 || /* st rx,NUM(r1) */ |
| 432 | (op & 0xfc1f0000) == 0xd8010000 || /* stfd Rx,NUM(r1) */ |
| 433 | (op & 0xfc1f0000) == 0xfc010000) { /* frsp, fp?,NUM(r1) */ |
| 434 | continue; |
| 435 | |
| 436 | /* store parameters in stack via frame pointer */ |
| 437 | } else if (framep && |
| 438 | ((op & 0xfc1f0000) == 0x901f0000 || /* st rx,NUM(r1) */ |
| 439 | (op & 0xfc1f0000) == 0xd81f0000 || /* stfd Rx,NUM(r1) */ |
| 440 | (op & 0xfc1f0000) == 0xfc1f0000)) { /* frsp, fp?,NUM(r1) */ |
| 441 | continue; |
| 442 | |
| 443 | /* Set up frame pointer */ |
| 444 | } else if (op == 0x603f0000 /* oril r31, r1, 0x0 */ |
| 445 | || op == 0x7c3f0b78) { /* mr r31, r1 */ |
| 446 | fdata->frameless = 0; |
| 447 | framep = 1; |
| 448 | fdata->alloca_reg = 31; |
| 449 | continue; |
| 450 | |
| 451 | /* Another way to set up the frame pointer. */ |
| 452 | } else if ((op & 0xfc1fffff) == 0x38010000) { /* addi rX, r1, 0x0 */ |
| 453 | fdata->frameless = 0; |
| 454 | framep = 1; |
| 455 | fdata->alloca_reg = (op & ~0x38010000) >> 21; |
| 456 | continue; |
| 457 | |
| 458 | } else { |
| 459 | break; |
| 460 | } |
| 461 | } |
| 462 | |
| 463 | #if 0 |
| 464 | /* I have problems with skipping over __main() that I need to address |
| 465 | * sometime. Previously, I used to use misc_function_vector which |
| 466 | * didn't work as well as I wanted to be. -MGO */ |
| 467 | |
| 468 | /* If the first thing after skipping a prolog is a branch to a function, |
| 469 | this might be a call to an initializer in main(), introduced by gcc2. |
| 470 | We'd like to skip over it as well. Fortunately, xlc does some extra |
| 471 | work before calling a function right after a prologue, thus we can |
| 472 | single out such gcc2 behaviour. */ |
| 473 | |
| 474 | |
| 475 | if ((op & 0xfc000001) == 0x48000001) { /* bl foo, an initializer function? */ |
| 476 | op = read_memory_integer (pc+4, 4); |
| 477 | |
| 478 | if (op == 0x4def7b82) { /* cror 0xf, 0xf, 0xf (nop) */ |
| 479 | |
| 480 | /* check and see if we are in main. If so, skip over this initializer |
| 481 | function as well. */ |
| 482 | |
| 483 | tmp = find_pc_misc_function (pc); |
| 484 | if (tmp >= 0 && STREQ (misc_function_vector [tmp].name, "main")) |
| 485 | return pc + 8; |
| 486 | } |
| 487 | } |
| 488 | #endif /* 0 */ |
| 489 | |
| 490 | fdata->offset = - fdata->offset; |
| 491 | return pc; |
| 492 | } |
| 493 | |
| 494 | |
| 495 | /************************************************************************* |
| 496 | Support for creating pushind a dummy frame into the stack, and popping |
| 497 | frames, etc. |
| 498 | *************************************************************************/ |
| 499 | |
| 500 | /* The total size of dummy frame is 436, which is; |
| 501 | |
| 502 | 32 gpr's - 128 bytes |
| 503 | 32 fpr's - 256 " |
| 504 | 7 the rest - 28 " |
| 505 | and 24 extra bytes for the callee's link area. The last 24 bytes |
| 506 | for the link area might not be necessary, since it will be taken |
| 507 | care of by push_arguments(). */ |
| 508 | |
| 509 | #define DUMMY_FRAME_SIZE 436 |
| 510 | |
| 511 | #define DUMMY_FRAME_ADDR_SIZE 10 |
| 512 | |
| 513 | /* Make sure you initialize these in somewhere, in case gdb gives up what it |
| 514 | was debugging and starts debugging something else. FIXMEibm */ |
| 515 | |
| 516 | static int dummy_frame_count = 0; |
| 517 | static int dummy_frame_size = 0; |
| 518 | static CORE_ADDR *dummy_frame_addr = 0; |
| 519 | |
| 520 | extern int stop_stack_dummy; |
| 521 | |
| 522 | /* push a dummy frame into stack, save all register. Currently we are saving |
| 523 | only gpr's and fpr's, which is not good enough! FIXMEmgo */ |
| 524 | |
| 525 | void |
| 526 | push_dummy_frame () |
| 527 | { |
| 528 | /* stack pointer. */ |
| 529 | CORE_ADDR sp; |
| 530 | /* Same thing, target byte order. */ |
| 531 | char sp_targ[4]; |
| 532 | |
| 533 | /* link register. */ |
| 534 | CORE_ADDR pc; |
| 535 | /* Same thing, target byte order. */ |
| 536 | char pc_targ[4]; |
| 537 | |
| 538 | /* Needed to figure out where to save the dummy link area. |
| 539 | FIXME: There should be an easier way to do this, no? tiemann 9/9/95. */ |
| 540 | struct rs6000_framedata fdata; |
| 541 | |
| 542 | int ii; |
| 543 | |
| 544 | target_fetch_registers (-1); |
| 545 | |
| 546 | if (dummy_frame_count >= dummy_frame_size) { |
| 547 | dummy_frame_size += DUMMY_FRAME_ADDR_SIZE; |
| 548 | if (dummy_frame_addr) |
| 549 | dummy_frame_addr = (CORE_ADDR*) xrealloc |
| 550 | (dummy_frame_addr, sizeof(CORE_ADDR) * (dummy_frame_size)); |
| 551 | else |
| 552 | dummy_frame_addr = (CORE_ADDR*) |
| 553 | xmalloc (sizeof(CORE_ADDR) * (dummy_frame_size)); |
| 554 | } |
| 555 | |
| 556 | sp = read_register(SP_REGNUM); |
| 557 | pc = read_register(PC_REGNUM); |
| 558 | store_address (pc_targ, 4, pc); |
| 559 | |
| 560 | skip_prologue (get_pc_function_start (pc), &fdata); |
| 561 | |
| 562 | dummy_frame_addr [dummy_frame_count++] = sp; |
| 563 | |
| 564 | /* Be careful! If the stack pointer is not decremented first, then kernel |
| 565 | thinks he is free to use the space underneath it. And kernel actually |
| 566 | uses that area for IPC purposes when executing ptrace(2) calls. So |
| 567 | before writing register values into the new frame, decrement and update |
| 568 | %sp first in order to secure your frame. */ |
| 569 | |
| 570 | /* FIXME: We don't check if the stack really has this much space. |
| 571 | This is a problem on the ppc simulator (which only grants one page |
| 572 | (4096 bytes) by default. */ |
| 573 | |
| 574 | write_register (SP_REGNUM, sp-DUMMY_FRAME_SIZE); |
| 575 | |
| 576 | /* gdb relies on the state of current_frame. We'd better update it, |
| 577 | otherwise things like do_registers_info() wouldn't work properly! */ |
| 578 | |
| 579 | flush_cached_frames (); |
| 580 | |
| 581 | /* save program counter in link register's space. */ |
| 582 | write_memory (sp + (fdata.lr_offset ? fdata.lr_offset : DEFAULT_LR_SAVE), |
| 583 | pc_targ, 4); |
| 584 | |
| 585 | /* save all floating point and general purpose registers here. */ |
| 586 | |
| 587 | /* fpr's, f0..f31 */ |
| 588 | for (ii = 0; ii < 32; ++ii) |
| 589 | write_memory (sp-8-(ii*8), ®isters[REGISTER_BYTE (31-ii+FP0_REGNUM)], 8); |
| 590 | |
| 591 | /* gpr's r0..r31 */ |
| 592 | for (ii=1; ii <=32; ++ii) |
| 593 | write_memory (sp-256-(ii*4), ®isters[REGISTER_BYTE (32-ii)], 4); |
| 594 | |
| 595 | /* so far, 32*2 + 32 words = 384 bytes have been written. |
| 596 | 7 extra registers in our register set: pc, ps, cnd, lr, cnt, xer, mq */ |
| 597 | |
| 598 | for (ii=1; ii <= (LAST_SP_REGNUM-FIRST_SP_REGNUM+1); ++ii) { |
| 599 | write_memory (sp-384-(ii*4), |
| 600 | ®isters[REGISTER_BYTE (FPLAST_REGNUM + ii)], 4); |
| 601 | } |
| 602 | |
| 603 | /* Save sp or so called back chain right here. */ |
| 604 | store_address (sp_targ, 4, sp); |
| 605 | write_memory (sp-DUMMY_FRAME_SIZE, sp_targ, 4); |
| 606 | sp -= DUMMY_FRAME_SIZE; |
| 607 | |
| 608 | /* And finally, this is the back chain. */ |
| 609 | write_memory (sp+8, pc_targ, 4); |
| 610 | } |
| 611 | |
| 612 | |
| 613 | /* Pop a dummy frame. |
| 614 | |
| 615 | In rs6000 when we push a dummy frame, we save all of the registers. This |
| 616 | is usually done before user calls a function explicitly. |
| 617 | |
| 618 | After a dummy frame is pushed, some instructions are copied into stack, |
| 619 | and stack pointer is decremented even more. Since we don't have a frame |
| 620 | pointer to get back to the parent frame of the dummy, we start having |
| 621 | trouble poping it. Therefore, we keep a dummy frame stack, keeping |
| 622 | addresses of dummy frames as such. When poping happens and when we |
| 623 | detect that was a dummy frame, we pop it back to its parent by using |
| 624 | dummy frame stack (`dummy_frame_addr' array). |
| 625 | |
| 626 | FIXME: This whole concept is broken. You should be able to detect |
| 627 | a dummy stack frame *on the user's stack itself*. When you do, |
| 628 | then you know the format of that stack frame -- including its |
| 629 | saved SP register! There should *not* be a separate stack in the |
| 630 | GDB process that keeps track of these dummy frames! -- gnu@cygnus.com Aug92 |
| 631 | */ |
| 632 | |
| 633 | static void |
| 634 | pop_dummy_frame () |
| 635 | { |
| 636 | CORE_ADDR sp, pc; |
| 637 | int ii; |
| 638 | sp = dummy_frame_addr [--dummy_frame_count]; |
| 639 | |
| 640 | /* restore all fpr's. */ |
| 641 | for (ii = 1; ii <= 32; ++ii) |
| 642 | read_memory (sp-(ii*8), ®isters[REGISTER_BYTE (32-ii+FP0_REGNUM)], 8); |
| 643 | |
| 644 | /* restore all gpr's */ |
| 645 | for (ii=1; ii <= 32; ++ii) { |
| 646 | read_memory (sp-256-(ii*4), ®isters[REGISTER_BYTE (32-ii)], 4); |
| 647 | } |
| 648 | |
| 649 | /* restore the rest of the registers. */ |
| 650 | for (ii=1; ii <=(LAST_SP_REGNUM-FIRST_SP_REGNUM+1); ++ii) |
| 651 | read_memory (sp-384-(ii*4), |
| 652 | ®isters[REGISTER_BYTE (FPLAST_REGNUM + ii)], 4); |
| 653 | |
| 654 | read_memory (sp-(DUMMY_FRAME_SIZE-8), |
| 655 | ®isters [REGISTER_BYTE(PC_REGNUM)], 4); |
| 656 | |
| 657 | /* when a dummy frame was being pushed, we had to decrement %sp first, in |
| 658 | order to secure astack space. Thus, saved %sp (or %r1) value, is not the |
| 659 | one we should restore. Change it with the one we need. */ |
| 660 | |
| 661 | memcpy (®isters [REGISTER_BYTE(FP_REGNUM)], (char *) &sp, sizeof (int)); |
| 662 | |
| 663 | /* Now we can restore all registers. */ |
| 664 | |
| 665 | target_store_registers (-1); |
| 666 | pc = read_pc (); |
| 667 | flush_cached_frames (); |
| 668 | } |
| 669 | |
| 670 | |
| 671 | /* pop the innermost frame, go back to the caller. */ |
| 672 | |
| 673 | void |
| 674 | pop_frame () |
| 675 | { |
| 676 | CORE_ADDR pc, lr, sp, prev_sp; /* %pc, %lr, %sp */ |
| 677 | struct rs6000_framedata fdata; |
| 678 | struct frame_info *frame = get_current_frame (); |
| 679 | int addr, ii; |
| 680 | |
| 681 | pc = read_pc (); |
| 682 | sp = FRAME_FP (frame); |
| 683 | |
| 684 | if (stop_stack_dummy) |
| 685 | { |
| 686 | #ifdef USE_GENERIC_DUMMY_FRAMES |
| 687 | generic_pop_dummy_frame (); |
| 688 | flush_cached_frames (); |
| 689 | return; |
| 690 | #else |
| 691 | if (dummy_frame_count) |
| 692 | pop_dummy_frame (); |
| 693 | return; |
| 694 | #endif |
| 695 | } |
| 696 | |
| 697 | /* Make sure that all registers are valid. */ |
| 698 | read_register_bytes (0, NULL, REGISTER_BYTES); |
| 699 | |
| 700 | /* figure out previous %pc value. If the function is frameless, it is |
| 701 | still in the link register, otherwise walk the frames and retrieve the |
| 702 | saved %pc value in the previous frame. */ |
| 703 | |
| 704 | addr = get_pc_function_start (frame->pc); |
| 705 | (void) skip_prologue (addr, &fdata); |
| 706 | |
| 707 | if (fdata.frameless) |
| 708 | prev_sp = sp; |
| 709 | else |
| 710 | prev_sp = read_memory_integer (sp, 4); |
| 711 | if (fdata.lr_offset == 0) |
| 712 | lr = read_register (LR_REGNUM); |
| 713 | else |
| 714 | lr = read_memory_integer (prev_sp + fdata.lr_offset, 4); |
| 715 | |
| 716 | /* reset %pc value. */ |
| 717 | write_register (PC_REGNUM, lr); |
| 718 | |
| 719 | /* reset register values if any was saved earlier. */ |
| 720 | |
| 721 | if (fdata.saved_gpr != -1) |
| 722 | { |
| 723 | addr = prev_sp + fdata.gpr_offset; |
| 724 | for (ii = fdata.saved_gpr; ii <= 31; ++ii) { |
| 725 | read_memory (addr, ®isters [REGISTER_BYTE (ii)], 4); |
| 726 | addr += 4; |
| 727 | } |
| 728 | } |
| 729 | |
| 730 | if (fdata.saved_fpr != -1) |
| 731 | { |
| 732 | addr = prev_sp + fdata.fpr_offset; |
| 733 | for (ii = fdata.saved_fpr; ii <= 31; ++ii) { |
| 734 | read_memory (addr, ®isters [REGISTER_BYTE (ii+FP0_REGNUM)], 8); |
| 735 | addr += 8; |
| 736 | } |
| 737 | } |
| 738 | |
| 739 | write_register (SP_REGNUM, prev_sp); |
| 740 | target_store_registers (-1); |
| 741 | flush_cached_frames (); |
| 742 | } |
| 743 | |
| 744 | /* fixup the call sequence of a dummy function, with the real function address. |
| 745 | its argumets will be passed by gdb. */ |
| 746 | |
| 747 | void |
| 748 | rs6000_fix_call_dummy (dummyname, pc, fun, nargs, args, type, gcc_p) |
| 749 | char *dummyname; |
| 750 | CORE_ADDR pc; |
| 751 | CORE_ADDR fun; |
| 752 | int nargs; |
| 753 | value_ptr *args; |
| 754 | struct type *type; |
| 755 | int gcc_p; |
| 756 | { |
| 757 | #define TOC_ADDR_OFFSET 20 |
| 758 | #define TARGET_ADDR_OFFSET 28 |
| 759 | |
| 760 | int ii; |
| 761 | CORE_ADDR target_addr; |
| 762 | |
| 763 | if (find_toc_address_hook != NULL) |
| 764 | { |
| 765 | CORE_ADDR tocvalue; |
| 766 | |
| 767 | tocvalue = (*find_toc_address_hook) (fun); |
| 768 | ii = *(int*)((char*)dummyname + TOC_ADDR_OFFSET); |
| 769 | ii = (ii & 0xffff0000) | (tocvalue >> 16); |
| 770 | *(int*)((char*)dummyname + TOC_ADDR_OFFSET) = ii; |
| 771 | |
| 772 | ii = *(int*)((char*)dummyname + TOC_ADDR_OFFSET+4); |
| 773 | ii = (ii & 0xffff0000) | (tocvalue & 0x0000ffff); |
| 774 | *(int*)((char*)dummyname + TOC_ADDR_OFFSET+4) = ii; |
| 775 | } |
| 776 | |
| 777 | target_addr = fun; |
| 778 | ii = *(int*)((char*)dummyname + TARGET_ADDR_OFFSET); |
| 779 | ii = (ii & 0xffff0000) | (target_addr >> 16); |
| 780 | *(int*)((char*)dummyname + TARGET_ADDR_OFFSET) = ii; |
| 781 | |
| 782 | ii = *(int*)((char*)dummyname + TARGET_ADDR_OFFSET+4); |
| 783 | ii = (ii & 0xffff0000) | (target_addr & 0x0000ffff); |
| 784 | *(int*)((char*)dummyname + TARGET_ADDR_OFFSET+4) = ii; |
| 785 | } |
| 786 | |
| 787 | /* Pass the arguments in either registers, or in the stack. In RS6000, |
| 788 | the first eight words of the argument list (that might be less than |
| 789 | eight parameters if some parameters occupy more than one word) are |
| 790 | passed in r3..r11 registers. float and double parameters are |
| 791 | passed in fpr's, in addition to that. Rest of the parameters if any |
| 792 | are passed in user stack. There might be cases in which half of the |
| 793 | parameter is copied into registers, the other half is pushed into |
| 794 | stack. |
| 795 | |
| 796 | If the function is returning a structure, then the return address is passed |
| 797 | in r3, then the first 7 words of the parameters can be passed in registers, |
| 798 | starting from r4. */ |
| 799 | |
| 800 | CORE_ADDR |
| 801 | push_arguments (nargs, args, sp, struct_return, struct_addr) |
| 802 | int nargs; |
| 803 | value_ptr *args; |
| 804 | CORE_ADDR sp; |
| 805 | int struct_return; |
| 806 | CORE_ADDR struct_addr; |
| 807 | { |
| 808 | int ii; |
| 809 | int len = 0; |
| 810 | int argno; /* current argument number */ |
| 811 | int argbytes; /* current argument byte */ |
| 812 | char tmp_buffer [50]; |
| 813 | int f_argno = 0; /* current floating point argno */ |
| 814 | |
| 815 | value_ptr arg = 0; |
| 816 | struct type *type; |
| 817 | |
| 818 | CORE_ADDR saved_sp; |
| 819 | |
| 820 | #ifndef USE_GENERIC_DUMMY_FRAMES |
| 821 | if ( dummy_frame_count <= 0) |
| 822 | printf_unfiltered ("FATAL ERROR -push_arguments()! frame not found!!\n"); |
| 823 | #endif /* GENERIC_DUMMY_FRAMES */ |
| 824 | |
| 825 | /* The first eight words of ther arguments are passed in registers. Copy |
| 826 | them appropriately. |
| 827 | |
| 828 | If the function is returning a `struct', then the first word (which |
| 829 | will be passed in r3) is used for struct return address. In that |
| 830 | case we should advance one word and start from r4 register to copy |
| 831 | parameters. */ |
| 832 | |
| 833 | ii = struct_return ? 1 : 0; |
| 834 | |
| 835 | /* |
| 836 | effectively indirect call... gcc does... |
| 837 | |
| 838 | return_val example( float, int); |
| 839 | |
| 840 | eabi: |
| 841 | float in fp0, int in r3 |
| 842 | offset of stack on overflow 8/16 |
| 843 | for varargs, must go by type. |
| 844 | power open: |
| 845 | float in r3&r4, int in r5 |
| 846 | offset of stack on overflow different |
| 847 | both: |
| 848 | return in r3 or f0. If no float, must study how gcc emulates floats; |
| 849 | pay attention to arg promotion. |
| 850 | User may have to cast\args to handle promotion correctly |
| 851 | since gdb won't know if prototype supplied or not. |
| 852 | */ |
| 853 | |
| 854 | for (argno=0, argbytes=0; argno < nargs && ii<8; ++ii) { |
| 855 | |
| 856 | arg = args[argno]; |
| 857 | type = check_typedef (VALUE_TYPE (arg)); |
| 858 | len = TYPE_LENGTH (type); |
| 859 | |
| 860 | if (TYPE_CODE (type) == TYPE_CODE_FLT) { |
| 861 | |
| 862 | /* floating point arguments are passed in fpr's, as well as gpr's. |
| 863 | There are 13 fpr's reserved for passing parameters. At this point |
| 864 | there is no way we would run out of them. */ |
| 865 | |
| 866 | if (len > 8) |
| 867 | printf_unfiltered ( |
| 868 | "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno); |
| 869 | |
| 870 | memcpy (®isters[REGISTER_BYTE(FP0_REGNUM + 1 + f_argno)], |
| 871 | VALUE_CONTENTS (arg), |
| 872 | len); |
| 873 | ++f_argno; |
| 874 | } |
| 875 | |
| 876 | if (len > 4) { |
| 877 | |
| 878 | /* Argument takes more than one register. */ |
| 879 | while (argbytes < len) { |
| 880 | memset (®isters[REGISTER_BYTE(ii+3)], 0, sizeof(int)); |
| 881 | memcpy (®isters[REGISTER_BYTE(ii+3)], |
| 882 | ((char*)VALUE_CONTENTS (arg))+argbytes, |
| 883 | (len - argbytes) > 4 ? 4 : len - argbytes); |
| 884 | ++ii, argbytes += 4; |
| 885 | |
| 886 | if (ii >= 8) |
| 887 | goto ran_out_of_registers_for_arguments; |
| 888 | } |
| 889 | argbytes = 0; |
| 890 | --ii; |
| 891 | } |
| 892 | else { /* Argument can fit in one register. No problem. */ |
| 893 | memset (®isters[REGISTER_BYTE(ii+3)], 0, sizeof(int)); |
| 894 | memcpy (®isters[REGISTER_BYTE(ii+3)], VALUE_CONTENTS (arg), len); |
| 895 | } |
| 896 | ++argno; |
| 897 | } |
| 898 | |
| 899 | ran_out_of_registers_for_arguments: |
| 900 | |
| 901 | #ifdef USE_GENERIC_DUMMY_FRAMES |
| 902 | saved_sp = read_sp (); |
| 903 | #else |
| 904 | /* location for 8 parameters are always reserved. */ |
| 905 | sp -= 4 * 8; |
| 906 | |
| 907 | /* another six words for back chain, TOC register, link register, etc. */ |
| 908 | sp -= 24; |
| 909 | #endif /* GENERIC_DUMMY_FRAMES */ |
| 910 | /* if there are more arguments, allocate space for them in |
| 911 | the stack, then push them starting from the ninth one. */ |
| 912 | |
| 913 | if ((argno < nargs) || argbytes) { |
| 914 | int space = 0, jj; |
| 915 | |
| 916 | if (argbytes) { |
| 917 | space += ((len - argbytes + 3) & -4); |
| 918 | jj = argno + 1; |
| 919 | } |
| 920 | else |
| 921 | jj = argno; |
| 922 | |
| 923 | for (; jj < nargs; ++jj) { |
| 924 | value_ptr val = args[jj]; |
| 925 | space += ((TYPE_LENGTH (VALUE_TYPE (val))) + 3) & -4; |
| 926 | } |
| 927 | |
| 928 | /* add location required for the rest of the parameters */ |
| 929 | space = (space + 7) & -8; |
| 930 | sp -= space; |
| 931 | |
| 932 | /* This is another instance we need to be concerned about securing our |
| 933 | stack space. If we write anything underneath %sp (r1), we might conflict |
| 934 | with the kernel who thinks he is free to use this area. So, update %sp |
| 935 | first before doing anything else. */ |
| 936 | |
| 937 | write_register (SP_REGNUM, sp); |
| 938 | |
| 939 | /* if the last argument copied into the registers didn't fit there |
| 940 | completely, push the rest of it into stack. */ |
| 941 | |
| 942 | if (argbytes) { |
| 943 | write_memory (sp+24+(ii*4), |
| 944 | ((char*)VALUE_CONTENTS (arg))+argbytes, |
| 945 | len - argbytes); |
| 946 | ++argno; |
| 947 | ii += ((len - argbytes + 3) & -4) / 4; |
| 948 | } |
| 949 | |
| 950 | /* push the rest of the arguments into stack. */ |
| 951 | for (; argno < nargs; ++argno) { |
| 952 | |
| 953 | arg = args[argno]; |
| 954 | type = check_typedef (VALUE_TYPE (arg)); |
| 955 | len = TYPE_LENGTH (type); |
| 956 | |
| 957 | |
| 958 | /* float types should be passed in fpr's, as well as in the stack. */ |
| 959 | if (TYPE_CODE (type) == TYPE_CODE_FLT && f_argno < 13) { |
| 960 | |
| 961 | if (len > 8) |
| 962 | printf_unfiltered ( |
| 963 | "Fatal Error: a floating point parameter #%d with a size > 8 is found!\n", argno); |
| 964 | |
| 965 | memcpy (®isters[REGISTER_BYTE(FP0_REGNUM + 1 + f_argno)], |
| 966 | VALUE_CONTENTS (arg), |
| 967 | len); |
| 968 | ++f_argno; |
| 969 | } |
| 970 | |
| 971 | write_memory (sp+24+(ii*4), (char *) VALUE_CONTENTS (arg), len); |
| 972 | ii += ((len + 3) & -4) / 4; |
| 973 | } |
| 974 | } |
| 975 | else |
| 976 | /* Secure stack areas first, before doing anything else. */ |
| 977 | write_register (SP_REGNUM, sp); |
| 978 | |
| 979 | #ifndef USE_GENERIC_DUMMY_FRAMES |
| 980 | /* we want to copy 24 bytes of target's frame to dummy's frame, |
| 981 | then set back chain to point to new frame. */ |
| 982 | |
| 983 | saved_sp = dummy_frame_addr [dummy_frame_count - 1]; |
| 984 | read_memory (saved_sp, tmp_buffer, 24); |
| 985 | write_memory (sp, tmp_buffer, 24); |
| 986 | #endif /* GENERIC_DUMMY_FRAMES */ |
| 987 | |
| 988 | /* set back chain properly */ |
| 989 | store_address (tmp_buffer, 4, saved_sp); |
| 990 | write_memory (sp, tmp_buffer, 4); |
| 991 | |
| 992 | target_store_registers (-1); |
| 993 | return sp; |
| 994 | } |
| 995 | #ifdef ELF_OBJECT_FORMAT |
| 996 | |
| 997 | /* Function: ppc_push_return_address (pc, sp) |
| 998 | Set up the return address for the inferior function call. */ |
| 999 | |
| 1000 | CORE_ADDR |
| 1001 | ppc_push_return_address (pc, sp) |
| 1002 | CORE_ADDR pc; |
| 1003 | CORE_ADDR sp; |
| 1004 | { |
| 1005 | write_register (LR_REGNUM, CALL_DUMMY_ADDRESS ()); |
| 1006 | return sp; |
| 1007 | } |
| 1008 | |
| 1009 | #endif |
| 1010 | |
| 1011 | /* a given return value in `regbuf' with a type `valtype', extract and copy its |
| 1012 | value into `valbuf' */ |
| 1013 | |
| 1014 | void |
| 1015 | extract_return_value (valtype, regbuf, valbuf) |
| 1016 | struct type *valtype; |
| 1017 | char regbuf[REGISTER_BYTES]; |
| 1018 | char *valbuf; |
| 1019 | { |
| 1020 | int offset = 0; |
| 1021 | |
| 1022 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) { |
| 1023 | |
| 1024 | double dd; float ff; |
| 1025 | /* floats and doubles are returned in fpr1. fpr's have a size of 8 bytes. |
| 1026 | We need to truncate the return value into float size (4 byte) if |
| 1027 | necessary. */ |
| 1028 | |
| 1029 | if (TYPE_LENGTH (valtype) > 4) /* this is a double */ |
| 1030 | memcpy (valbuf, |
| 1031 | ®buf[REGISTER_BYTE (FP0_REGNUM + 1)], |
| 1032 | TYPE_LENGTH (valtype)); |
| 1033 | else { /* float */ |
| 1034 | memcpy (&dd, ®buf[REGISTER_BYTE (FP0_REGNUM + 1)], 8); |
| 1035 | ff = (float)dd; |
| 1036 | memcpy (valbuf, &ff, sizeof(float)); |
| 1037 | } |
| 1038 | } |
| 1039 | else { |
| 1040 | /* return value is copied starting from r3. */ |
| 1041 | if (TARGET_BYTE_ORDER == BIG_ENDIAN |
| 1042 | && TYPE_LENGTH (valtype) < REGISTER_RAW_SIZE (3)) |
| 1043 | offset = REGISTER_RAW_SIZE (3) - TYPE_LENGTH (valtype); |
| 1044 | |
| 1045 | memcpy (valbuf, |
| 1046 | regbuf + REGISTER_BYTE (3) + offset, |
| 1047 | TYPE_LENGTH (valtype)); |
| 1048 | } |
| 1049 | } |
| 1050 | |
| 1051 | |
| 1052 | /* keep structure return address in this variable. |
| 1053 | FIXME: This is a horrid kludge which should not be allowed to continue |
| 1054 | living. This only allows a single nested call to a structure-returning |
| 1055 | function. Come on, guys! -- gnu@cygnus.com, Aug 92 */ |
| 1056 | |
| 1057 | CORE_ADDR rs6000_struct_return_address; |
| 1058 | |
| 1059 | |
| 1060 | /* Indirect function calls use a piece of trampoline code to do context |
| 1061 | switching, i.e. to set the new TOC table. Skip such code if we are on |
| 1062 | its first instruction (as when we have single-stepped to here). |
| 1063 | Also skip shared library trampoline code (which is different from |
| 1064 | indirect function call trampolines). |
| 1065 | Result is desired PC to step until, or NULL if we are not in |
| 1066 | trampoline code. */ |
| 1067 | |
| 1068 | CORE_ADDR |
| 1069 | skip_trampoline_code (pc) |
| 1070 | CORE_ADDR pc; |
| 1071 | { |
| 1072 | register unsigned int ii, op; |
| 1073 | CORE_ADDR solib_target_pc; |
| 1074 | |
| 1075 | static unsigned trampoline_code[] = { |
| 1076 | 0x800b0000, /* l r0,0x0(r11) */ |
| 1077 | 0x90410014, /* st r2,0x14(r1) */ |
| 1078 | 0x7c0903a6, /* mtctr r0 */ |
| 1079 | 0x804b0004, /* l r2,0x4(r11) */ |
| 1080 | 0x816b0008, /* l r11,0x8(r11) */ |
| 1081 | 0x4e800420, /* bctr */ |
| 1082 | 0x4e800020, /* br */ |
| 1083 | 0 |
| 1084 | }; |
| 1085 | |
| 1086 | /* If pc is in a shared library trampoline, return its target. */ |
| 1087 | solib_target_pc = find_solib_trampoline_target (pc); |
| 1088 | if (solib_target_pc) |
| 1089 | return solib_target_pc; |
| 1090 | |
| 1091 | for (ii=0; trampoline_code[ii]; ++ii) { |
| 1092 | op = read_memory_integer (pc + (ii*4), 4); |
| 1093 | if (op != trampoline_code [ii]) |
| 1094 | return 0; |
| 1095 | } |
| 1096 | ii = read_register (11); /* r11 holds destination addr */ |
| 1097 | pc = read_memory_integer (ii, 4); /* (r11) value */ |
| 1098 | return pc; |
| 1099 | } |
| 1100 | |
| 1101 | /* Determines whether the function FI has a frame on the stack or not. */ |
| 1102 | |
| 1103 | int |
| 1104 | frameless_function_invocation (fi) |
| 1105 | struct frame_info *fi; |
| 1106 | { |
| 1107 | CORE_ADDR func_start; |
| 1108 | struct rs6000_framedata fdata; |
| 1109 | |
| 1110 | /* Don't even think about framelessness except on the innermost frame |
| 1111 | or if the function was interrupted by a signal. */ |
| 1112 | if (fi->next != NULL && !fi->next->signal_handler_caller) |
| 1113 | return 0; |
| 1114 | |
| 1115 | func_start = get_pc_function_start (fi->pc); |
| 1116 | |
| 1117 | /* If we failed to find the start of the function, it is a mistake |
| 1118 | to inspect the instructions. */ |
| 1119 | |
| 1120 | if (!func_start) |
| 1121 | { |
| 1122 | /* A frame with a zero PC is usually created by dereferencing a NULL |
| 1123 | function pointer, normally causing an immediate core dump of the |
| 1124 | inferior. Mark function as frameless, as the inferior has no chance |
| 1125 | of setting up a stack frame. */ |
| 1126 | if (fi->pc == 0) |
| 1127 | return 1; |
| 1128 | else |
| 1129 | return 0; |
| 1130 | } |
| 1131 | |
| 1132 | (void) skip_prologue (func_start, &fdata); |
| 1133 | return fdata.frameless; |
| 1134 | } |
| 1135 | |
| 1136 | /* Return the PC saved in a frame */ |
| 1137 | |
| 1138 | unsigned long |
| 1139 | frame_saved_pc (fi) |
| 1140 | struct frame_info *fi; |
| 1141 | { |
| 1142 | CORE_ADDR func_start; |
| 1143 | struct rs6000_framedata fdata; |
| 1144 | |
| 1145 | if (fi->signal_handler_caller) |
| 1146 | return read_memory_integer (fi->frame + SIG_FRAME_PC_OFFSET, 4); |
| 1147 | |
| 1148 | #ifdef USE_GENERIC_DUMMY_FRAMES |
| 1149 | if (PC_IN_CALL_DUMMY (fi->pc, fi->frame, fi->frame)) |
| 1150 | return generic_read_register_dummy(fi->pc, fi->frame, PC_REGNUM); |
| 1151 | #endif /* GENERIC_DUMMY_FRAMES */ |
| 1152 | |
| 1153 | func_start = get_pc_function_start (fi->pc); |
| 1154 | |
| 1155 | /* If we failed to find the start of the function, it is a mistake |
| 1156 | to inspect the instructions. */ |
| 1157 | if (!func_start) |
| 1158 | return 0; |
| 1159 | |
| 1160 | (void) skip_prologue (func_start, &fdata); |
| 1161 | |
| 1162 | if (fdata.lr_offset == 0 && fi->next != NULL) |
| 1163 | { |
| 1164 | if (fi->next->signal_handler_caller) |
| 1165 | return read_memory_integer (fi->next->frame + SIG_FRAME_LR_OFFSET, 4); |
| 1166 | else |
| 1167 | return read_memory_integer (rs6000_frame_chain (fi) + DEFAULT_LR_SAVE, |
| 1168 | 4); |
| 1169 | } |
| 1170 | |
| 1171 | if (fdata.lr_offset == 0) |
| 1172 | return read_register (LR_REGNUM); |
| 1173 | |
| 1174 | return read_memory_integer (rs6000_frame_chain (fi) + fdata.lr_offset, 4); |
| 1175 | } |
| 1176 | |
| 1177 | /* If saved registers of frame FI are not known yet, read and cache them. |
| 1178 | &FDATAP contains rs6000_framedata; TDATAP can be NULL, |
| 1179 | in which case the framedata are read. */ |
| 1180 | |
| 1181 | static void |
| 1182 | frame_get_saved_regs (fi, fdatap) |
| 1183 | struct frame_info *fi; |
| 1184 | struct rs6000_framedata *fdatap; |
| 1185 | { |
| 1186 | int ii; |
| 1187 | CORE_ADDR frame_addr; |
| 1188 | struct rs6000_framedata work_fdata; |
| 1189 | |
| 1190 | if (fi->saved_regs) |
| 1191 | return; |
| 1192 | |
| 1193 | if (fdatap == NULL) |
| 1194 | { |
| 1195 | fdatap = &work_fdata; |
| 1196 | (void) skip_prologue (get_pc_function_start (fi->pc), fdatap); |
| 1197 | } |
| 1198 | |
| 1199 | frame_saved_regs_zalloc (fi); |
| 1200 | |
| 1201 | /* If there were any saved registers, figure out parent's stack |
| 1202 | pointer. */ |
| 1203 | /* The following is true only if the frame doesn't have a call to |
| 1204 | alloca(), FIXME. */ |
| 1205 | |
| 1206 | if (fdatap->saved_fpr == 0 && fdatap->saved_gpr == 0 |
| 1207 | && fdatap->lr_offset == 0 && fdatap->cr_offset == 0) |
| 1208 | frame_addr = 0; |
| 1209 | else if (fi->prev && fi->prev->frame) |
| 1210 | frame_addr = fi->prev->frame; |
| 1211 | else |
| 1212 | frame_addr = read_memory_integer (fi->frame, 4); |
| 1213 | |
| 1214 | /* if != -1, fdatap->saved_fpr is the smallest number of saved_fpr. |
| 1215 | All fpr's from saved_fpr to fp31 are saved. */ |
| 1216 | |
| 1217 | if (fdatap->saved_fpr >= 0) |
| 1218 | { |
| 1219 | int i; |
| 1220 | int fpr_offset = frame_addr + fdatap->fpr_offset; |
| 1221 | for (i = fdatap->saved_fpr; i < 32; i++) |
| 1222 | { |
| 1223 | fi->saved_regs [FP0_REGNUM + i] = fpr_offset; |
| 1224 | fpr_offset += 8; |
| 1225 | } |
| 1226 | } |
| 1227 | |
| 1228 | /* if != -1, fdatap->saved_gpr is the smallest number of saved_gpr. |
| 1229 | All gpr's from saved_gpr to gpr31 are saved. */ |
| 1230 | |
| 1231 | if (fdatap->saved_gpr >= 0) |
| 1232 | { |
| 1233 | int i; |
| 1234 | int gpr_offset = frame_addr + fdatap->gpr_offset; |
| 1235 | for (i = fdatap->saved_gpr; i < 32; i++) |
| 1236 | { |
| 1237 | fi->saved_regs [i] = gpr_offset; |
| 1238 | gpr_offset += 4; |
| 1239 | } |
| 1240 | } |
| 1241 | |
| 1242 | /* If != 0, fdatap->cr_offset is the offset from the frame that holds |
| 1243 | the CR. */ |
| 1244 | if (fdatap->cr_offset != 0) |
| 1245 | fi->saved_regs [CR_REGNUM] = frame_addr + fdatap->cr_offset; |
| 1246 | |
| 1247 | /* If != 0, fdatap->lr_offset is the offset from the frame that holds |
| 1248 | the LR. */ |
| 1249 | if (fdatap->lr_offset != 0) |
| 1250 | fi->saved_regs [LR_REGNUM] = frame_addr + fdatap->lr_offset; |
| 1251 | } |
| 1252 | |
| 1253 | /* Return the address of a frame. This is the inital %sp value when the frame |
| 1254 | was first allocated. For functions calling alloca(), it might be saved in |
| 1255 | an alloca register. */ |
| 1256 | |
| 1257 | static CORE_ADDR |
| 1258 | frame_initial_stack_address (fi) |
| 1259 | struct frame_info *fi; |
| 1260 | { |
| 1261 | CORE_ADDR tmpaddr; |
| 1262 | struct rs6000_framedata fdata; |
| 1263 | struct frame_info *callee_fi; |
| 1264 | |
| 1265 | /* if the initial stack pointer (frame address) of this frame is known, |
| 1266 | just return it. */ |
| 1267 | |
| 1268 | if (fi->extra_info->initial_sp) |
| 1269 | return fi->extra_info->initial_sp; |
| 1270 | |
| 1271 | /* find out if this function is using an alloca register.. */ |
| 1272 | |
| 1273 | (void) skip_prologue (get_pc_function_start (fi->pc), &fdata); |
| 1274 | |
| 1275 | /* if saved registers of this frame are not known yet, read and cache them. */ |
| 1276 | |
| 1277 | if (!fi->saved_regs) |
| 1278 | frame_get_saved_regs (fi, &fdata); |
| 1279 | |
| 1280 | /* If no alloca register used, then fi->frame is the value of the %sp for |
| 1281 | this frame, and it is good enough. */ |
| 1282 | |
| 1283 | if (fdata.alloca_reg < 0) |
| 1284 | { |
| 1285 | fi->extra_info->initial_sp = fi->frame; |
| 1286 | return fi->extra_info->initial_sp; |
| 1287 | } |
| 1288 | |
| 1289 | /* This function has an alloca register. If this is the top-most frame |
| 1290 | (with the lowest address), the value in alloca register is good. */ |
| 1291 | |
| 1292 | if (!fi->next) |
| 1293 | return fi->extra_info->initial_sp = read_register (fdata.alloca_reg); |
| 1294 | |
| 1295 | /* Otherwise, this is a caller frame. Callee has usually already saved |
| 1296 | registers, but there are exceptions (such as when the callee |
| 1297 | has no parameters). Find the address in which caller's alloca |
| 1298 | register is saved. */ |
| 1299 | |
| 1300 | for (callee_fi = fi->next; callee_fi; callee_fi = callee_fi->next) { |
| 1301 | |
| 1302 | if (!callee_fi->saved_regs) |
| 1303 | frame_get_saved_regs (callee_fi, NULL); |
| 1304 | |
| 1305 | /* this is the address in which alloca register is saved. */ |
| 1306 | |
| 1307 | tmpaddr = callee_fi->saved_regs [fdata.alloca_reg]; |
| 1308 | if (tmpaddr) { |
| 1309 | fi->extra_info->initial_sp = read_memory_integer (tmpaddr, 4); |
| 1310 | return fi->extra_info->initial_sp; |
| 1311 | } |
| 1312 | |
| 1313 | /* Go look into deeper levels of the frame chain to see if any one of |
| 1314 | the callees has saved alloca register. */ |
| 1315 | } |
| 1316 | |
| 1317 | /* If alloca register was not saved, by the callee (or any of its callees) |
| 1318 | then the value in the register is still good. */ |
| 1319 | |
| 1320 | fi->extra_info->initial_sp = read_register (fdata.alloca_reg); |
| 1321 | return fi->extra_info->initial_sp; |
| 1322 | } |
| 1323 | |
| 1324 | CORE_ADDR |
| 1325 | rs6000_frame_chain (thisframe) |
| 1326 | struct frame_info *thisframe; |
| 1327 | { |
| 1328 | CORE_ADDR fp; |
| 1329 | |
| 1330 | #ifdef USE_GENERIC_DUMMY_FRAMES |
| 1331 | if (PC_IN_CALL_DUMMY (thisframe->pc, thisframe->frame, thisframe->frame)) |
| 1332 | return thisframe->frame; /* dummy frame same as caller's frame */ |
| 1333 | #endif /* GENERIC_DUMMY_FRAMES */ |
| 1334 | |
| 1335 | if (inside_entry_file (thisframe->pc) || |
| 1336 | thisframe->pc == entry_point_address ()) |
| 1337 | return 0; |
| 1338 | |
| 1339 | if (thisframe->signal_handler_caller) |
| 1340 | fp = read_memory_integer (thisframe->frame + SIG_FRAME_FP_OFFSET, 4); |
| 1341 | else if (thisframe->next != NULL |
| 1342 | && thisframe->next->signal_handler_caller |
| 1343 | && frameless_function_invocation (thisframe)) |
| 1344 | /* A frameless function interrupted by a signal did not change the |
| 1345 | frame pointer. */ |
| 1346 | fp = FRAME_FP (thisframe); |
| 1347 | else |
| 1348 | fp = read_memory_integer ((thisframe)->frame, 4); |
| 1349 | |
| 1350 | #ifdef USE_GENERIC_DUMMY_FRAMES |
| 1351 | { |
| 1352 | CORE_ADDR fpp, lr; |
| 1353 | |
| 1354 | lr = read_register (LR_REGNUM); |
| 1355 | if (lr == entry_point_address ()) |
| 1356 | if (fp != 0 && (fpp = read_memory_integer (fp, 4)) != 0) |
| 1357 | if (PC_IN_CALL_DUMMY (lr, fpp, fpp)) |
| 1358 | return fpp; |
| 1359 | } |
| 1360 | #endif /* GENERIC_DUMMY_FRAMES */ |
| 1361 | return fp; |
| 1362 | } |
| 1363 | \f |
| 1364 | /* Return nonzero if ADDR (a function pointer) is in the data space and |
| 1365 | is therefore a special function pointer. */ |
| 1366 | |
| 1367 | int |
| 1368 | is_magic_function_pointer (addr) |
| 1369 | CORE_ADDR addr; |
| 1370 | { |
| 1371 | struct obj_section *s; |
| 1372 | |
| 1373 | s = find_pc_section (addr); |
| 1374 | if (s && s->the_bfd_section->flags & SEC_CODE) |
| 1375 | return 0; |
| 1376 | else |
| 1377 | return 1; |
| 1378 | } |
| 1379 | |
| 1380 | #ifdef GDB_TARGET_POWERPC |
| 1381 | int |
| 1382 | gdb_print_insn_powerpc (memaddr, info) |
| 1383 | bfd_vma memaddr; |
| 1384 | disassemble_info *info; |
| 1385 | { |
| 1386 | if (TARGET_BYTE_ORDER == BIG_ENDIAN) |
| 1387 | return print_insn_big_powerpc (memaddr, info); |
| 1388 | else |
| 1389 | return print_insn_little_powerpc (memaddr, info); |
| 1390 | } |
| 1391 | #endif |
| 1392 | |
| 1393 | /* Function: get_saved_register |
| 1394 | Just call the generic_get_saved_register function. */ |
| 1395 | |
| 1396 | #ifdef USE_GENERIC_DUMMY_FRAMES |
| 1397 | void |
| 1398 | get_saved_register (raw_buffer, optimized, addrp, frame, regnum, lval) |
| 1399 | char *raw_buffer; |
| 1400 | int *optimized; |
| 1401 | CORE_ADDR *addrp; |
| 1402 | struct frame_info *frame; |
| 1403 | int regnum; |
| 1404 | enum lval_type *lval; |
| 1405 | { |
| 1406 | generic_get_saved_register (raw_buffer, optimized, addrp, |
| 1407 | frame, regnum, lval); |
| 1408 | } |
| 1409 | #endif |
| 1410 | |
| 1411 | |
| 1412 | void |
| 1413 | _initialize_rs6000_tdep () |
| 1414 | { |
| 1415 | /* FIXME, this should not be decided via ifdef. */ |
| 1416 | #ifdef GDB_TARGET_POWERPC |
| 1417 | tm_print_insn = gdb_print_insn_powerpc; |
| 1418 | #else |
| 1419 | tm_print_insn = print_insn_rs6000; |
| 1420 | #endif |
| 1421 | } |