| 1 | |
| 2 | /* Copyright (c) 1982 Regents of the University of California */ |
| 3 | |
| 4 | static char sccsid[] = "@(#)runtime.c 1.10 %G%"; |
| 5 | |
| 6 | /* |
| 7 | * Runtime organization dependent routines, mostly dealing with |
| 8 | * activation records. |
| 9 | */ |
| 10 | |
| 11 | #include "defs.h" |
| 12 | #include "runtime.h" |
| 13 | #include "process.h" |
| 14 | #include "machine.h" |
| 15 | #include "events.h" |
| 16 | #include "mappings.h" |
| 17 | #include "symbols.h" |
| 18 | #include "tree.h" |
| 19 | #include "eval.h" |
| 20 | #include "operators.h" |
| 21 | #include "object.h" |
| 22 | #include <sys/param.h> |
| 23 | |
| 24 | #ifndef public |
| 25 | typedef struct Frame *Frame; |
| 26 | |
| 27 | #include "machine.h" |
| 28 | #endif |
| 29 | |
| 30 | #define NSAVEREG 12 |
| 31 | |
| 32 | struct Frame { |
| 33 | Integer condition_handler; |
| 34 | Integer mask; |
| 35 | Address save_ap; /* argument pointer */ |
| 36 | Address save_fp; /* frame pointer */ |
| 37 | Address save_pc; /* program counter */ |
| 38 | Word save_reg[NSAVEREG]; /* not necessarily there */ |
| 39 | }; |
| 40 | |
| 41 | private Boolean walkingstack = false; |
| 42 | |
| 43 | /* |
| 44 | * Set a frame to the current activation record. |
| 45 | */ |
| 46 | |
| 47 | private getcurframe(frp) |
| 48 | register Frame frp; |
| 49 | { |
| 50 | register int i; |
| 51 | |
| 52 | checkref(frp); |
| 53 | frp->mask = reg(NREG); |
| 54 | frp->save_ap = reg(ARGP); |
| 55 | frp->save_fp = reg(FRP); |
| 56 | frp->save_pc = reg(PROGCTR) + 1; |
| 57 | for (i = 0; i < NSAVEREG; i++) { |
| 58 | frp->save_reg[i] = reg(i); |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | /* |
| 63 | * Return a pointer to the next activation record up the stack. |
| 64 | * Return nil if there is none. |
| 65 | * Writes over space pointed to by given argument. |
| 66 | */ |
| 67 | |
| 68 | #define bis(b, n) ((b & (1 << (n))) != 0) |
| 69 | |
| 70 | private Frame nextframe(frp) |
| 71 | Frame frp; |
| 72 | { |
| 73 | register Frame newfrp; |
| 74 | struct Frame frame; |
| 75 | register Integer i, j, mask; |
| 76 | Address prev_frame, callpc; |
| 77 | static Integer ntramp = 0; |
| 78 | |
| 79 | newfrp = frp; |
| 80 | prev_frame = frp->save_fp; |
| 81 | |
| 82 | /* |
| 83 | * The check for interrupt generated frames is taken from adb with only |
| 84 | * partial understanding. If you're in "sub" and on a sigxxx "sigsub" |
| 85 | * gets control, then the stack does NOT look like <main, sub, sigsub>. |
| 86 | * |
| 87 | * As best I can make out it looks like: |
| 88 | * |
| 89 | * <main, (machine check exception block + sub), sysframe, sigsub>. |
| 90 | * |
| 91 | * When the signal occurs an exception block and a frame for the routine |
| 92 | * in which it occured are pushed on the user stack. Then another frame |
| 93 | * is pushed corresponding to a call from the kernel to sigsub. |
| 94 | * |
| 95 | * The addr in sub at which the exception occured is not in sub.save_pc |
| 96 | * but in the machine check exception block. It is at the magic address |
| 97 | * fp + 84. |
| 98 | * |
| 99 | * The current approach ignores the sys_frame (what adb reports as sigtramp) |
| 100 | * and takes the pc for sub from the exception block. This allows the |
| 101 | * "where" command to report <main, sub, sigsub>, which seems reasonable. |
| 102 | */ |
| 103 | |
| 104 | nextf: |
| 105 | dread(&frame, prev_frame, sizeof(struct Frame)); |
| 106 | if (ntramp == 1) { |
| 107 | dread(&callpc, prev_frame + 84, sizeof(callpc)); |
| 108 | } else { |
| 109 | callpc = frame.save_pc; |
| 110 | } |
| 111 | if (frame.save_fp == nil) { |
| 112 | newfrp = nil; |
| 113 | } else if (callpc > 0x80000000 - 0x200 * UPAGES ) { |
| 114 | ntramp++; |
| 115 | prev_frame = frame.save_fp; |
| 116 | goto nextf; |
| 117 | } else { |
| 118 | frame.save_pc = callpc; |
| 119 | ntramp = 0; |
| 120 | mask = ((frame.mask >> 16) & 0x0fff); |
| 121 | j = 0; |
| 122 | for (i = 0; i < NSAVEREG; i++) { |
| 123 | if (bis(mask, i)) { |
| 124 | newfrp->save_reg[i] = frame.save_reg[j]; |
| 125 | ++j; |
| 126 | } |
| 127 | } |
| 128 | newfrp->condition_handler = frame.condition_handler; |
| 129 | newfrp->mask = mask; |
| 130 | newfrp->save_ap = frame.save_ap; |
| 131 | newfrp->save_fp = frame.save_fp; |
| 132 | newfrp->save_pc = frame.save_pc; |
| 133 | } |
| 134 | return newfrp; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * Return the frame associated with the given function. |
| 139 | * If the function is nil, return the most recently activated frame. |
| 140 | * |
| 141 | * Static allocation for the frame. |
| 142 | */ |
| 143 | |
| 144 | public Frame findframe(f) |
| 145 | Symbol f; |
| 146 | { |
| 147 | register Frame frp; |
| 148 | static struct Frame frame; |
| 149 | Symbol p; |
| 150 | |
| 151 | frp = &frame; |
| 152 | getcurframe(frp); |
| 153 | if (f == nil) |
| 154 | return (frp); |
| 155 | /* |
| 156 | * Starting at the current stack frame, |
| 157 | * walk backwards looking for a symbol |
| 158 | * match. Beware of local blocks which |
| 159 | * have a back pointer but no stack frame. |
| 160 | */ |
| 161 | p = whatblock(frp->save_pc); |
| 162 | while (p != f) { |
| 163 | if (p == program) { |
| 164 | frp = nil; |
| 165 | break; |
| 166 | } |
| 167 | if (isinline(p)) { |
| 168 | p = container(p); |
| 169 | continue; |
| 170 | } |
| 171 | frp = nextframe(frp); |
| 172 | if (frp == nil) |
| 173 | break; |
| 174 | p = whatblock(frp->save_pc); |
| 175 | } |
| 176 | return (frp); |
| 177 | } |
| 178 | |
| 179 | /* |
| 180 | * Find the return address of the current procedure/function. |
| 181 | */ |
| 182 | |
| 183 | public Address return_addr() |
| 184 | { |
| 185 | Frame frp; |
| 186 | Address addr; |
| 187 | struct Frame frame; |
| 188 | |
| 189 | frp = &frame; |
| 190 | getcurframe(frp); |
| 191 | frp = nextframe(frp); |
| 192 | if (frp == nil) { |
| 193 | addr = 0; |
| 194 | } else { |
| 195 | addr = frp->save_pc; |
| 196 | } |
| 197 | return addr; |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * Push the value associated with the current function. |
| 202 | */ |
| 203 | |
| 204 | public pushretval(len, isindirect) |
| 205 | Integer len; |
| 206 | Boolean isindirect; |
| 207 | { |
| 208 | Word r0; |
| 209 | |
| 210 | r0 = reg(0); |
| 211 | if (isindirect) { |
| 212 | rpush((Address) r0, len); |
| 213 | } else { |
| 214 | switch (len) { |
| 215 | case sizeof(char): |
| 216 | push(char, r0); |
| 217 | break; |
| 218 | |
| 219 | case sizeof(short): |
| 220 | push(short, r0); |
| 221 | break; |
| 222 | |
| 223 | default: |
| 224 | if (len == sizeof(Word)) { |
| 225 | push(Word, r0); |
| 226 | } else if (len == 2*sizeof(Word)) { |
| 227 | push(Word, r0); |
| 228 | push(Word, reg(1)); |
| 229 | } else { |
| 230 | panic("not indirect in pushretval?"); |
| 231 | } |
| 232 | break; |
| 233 | } |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | /* |
| 238 | * Return the base address for locals in the given frame. |
| 239 | */ |
| 240 | |
| 241 | public Address locals_base(frp) |
| 242 | register Frame frp; |
| 243 | { |
| 244 | return (frp == nil) ? reg(FRP) : frp->save_fp; |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * Return the base address for arguments in the given frame. |
| 249 | */ |
| 250 | |
| 251 | public Address args_base(frp) |
| 252 | register Frame frp; |
| 253 | { |
| 254 | return (frp == nil) ? reg(ARGP) : frp->save_ap; |
| 255 | } |
| 256 | |
| 257 | /* |
| 258 | * Return saved register n from the given frame. |
| 259 | */ |
| 260 | |
| 261 | public Word savereg(n, frp) |
| 262 | register Integer n; |
| 263 | register Frame frp; |
| 264 | { |
| 265 | register Word w; |
| 266 | |
| 267 | if (frp == nil) { |
| 268 | w = reg(n); |
| 269 | } else { |
| 270 | switch (n) { |
| 271 | case ARGP: |
| 272 | w = frp->save_ap; |
| 273 | break; |
| 274 | |
| 275 | case FRP: |
| 276 | w = frp->save_fp; |
| 277 | break; |
| 278 | |
| 279 | case STKP: |
| 280 | w = reg(STKP); |
| 281 | break; |
| 282 | |
| 283 | case PROGCTR: |
| 284 | w = frp->save_pc; |
| 285 | break; |
| 286 | |
| 287 | default: |
| 288 | assert(n >= 0 and n < NSAVEREG); |
| 289 | w = frp->save_reg[n]; |
| 290 | break; |
| 291 | } |
| 292 | } |
| 293 | return w; |
| 294 | } |
| 295 | |
| 296 | /* |
| 297 | * Return the nth argument to the current procedure. |
| 298 | */ |
| 299 | |
| 300 | public Word argn(n, frp) |
| 301 | Integer n; |
| 302 | Frame frp; |
| 303 | { |
| 304 | Word w; |
| 305 | |
| 306 | dread(&w, args_base(frp) + (n * sizeof(Word)), sizeof(w)); |
| 307 | return w; |
| 308 | } |
| 309 | |
| 310 | /* |
| 311 | * Calculate the entry address for a procedure or function parameter, |
| 312 | * given the address of the descriptor. |
| 313 | */ |
| 314 | |
| 315 | public Address fparamaddr(a) |
| 316 | Address a; |
| 317 | { |
| 318 | Address r; |
| 319 | |
| 320 | dread(&r, a, sizeof(r)); |
| 321 | return r; |
| 322 | } |
| 323 | |
| 324 | /* |
| 325 | * Print a list of currently active blocks starting with most recent. |
| 326 | */ |
| 327 | |
| 328 | public wherecmd() |
| 329 | { |
| 330 | walkstack(false); |
| 331 | } |
| 332 | |
| 333 | /* |
| 334 | * Dump the world to the given file. |
| 335 | * Like "where", but variables are dumped also. |
| 336 | */ |
| 337 | |
| 338 | public dump() |
| 339 | { |
| 340 | walkstack(true); |
| 341 | } |
| 342 | |
| 343 | /* |
| 344 | * Walk the stack of active procedures printing information |
| 345 | * about each active procedure. |
| 346 | */ |
| 347 | |
| 348 | private walkstack(dumpvariables) |
| 349 | Boolean dumpvariables; |
| 350 | { |
| 351 | register Frame frp; |
| 352 | register Symbol f; |
| 353 | register Boolean save; |
| 354 | register Lineno line; |
| 355 | struct Frame frame; |
| 356 | |
| 357 | if (notstarted(process)) { |
| 358 | error("program is not active"); |
| 359 | } else { |
| 360 | save = walkingstack; |
| 361 | walkingstack = true; |
| 362 | frp = &frame; |
| 363 | getcurframe(frp); |
| 364 | f = whatblock(frp->save_pc); |
| 365 | do { |
| 366 | printf("%s", symname(f)); |
| 367 | if (not isinline(f)) { |
| 368 | printparams(f, frp); |
| 369 | } |
| 370 | line = srcline(frp->save_pc - 1); |
| 371 | if (line != 0) { |
| 372 | printf(", line %d", line); |
| 373 | printf(" in \"%s\"\n", srcfilename(frp->save_pc - 1)); |
| 374 | } else { |
| 375 | printf(" at 0x%x\n", frp->save_pc); |
| 376 | } |
| 377 | if (dumpvariables) { |
| 378 | dumpvars(f, frp); |
| 379 | putchar('\n'); |
| 380 | } |
| 381 | if (isinline(f)) { |
| 382 | f = container(f); |
| 383 | } else { |
| 384 | frp = nextframe(frp); |
| 385 | if (frp != nil) { |
| 386 | f = whatblock(frp->save_pc); |
| 387 | } |
| 388 | } |
| 389 | } while (frp != nil and f != program); |
| 390 | if (dumpvariables) { |
| 391 | printf("in \"%s\":\n", symname(program)); |
| 392 | dumpvars(program, nil); |
| 393 | putchar('\n'); |
| 394 | } |
| 395 | walkingstack = save; |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | /* |
| 400 | * Find the entry point of a procedure or function. |
| 401 | */ |
| 402 | |
| 403 | public findbeginning(f) |
| 404 | Symbol f; |
| 405 | { |
| 406 | f->symvalue.funcv.beginaddr += 2; |
| 407 | } |
| 408 | |
| 409 | /* |
| 410 | * Return the address corresponding to the first line in a function. |
| 411 | */ |
| 412 | |
| 413 | public Address firstline(f) |
| 414 | Symbol f; |
| 415 | { |
| 416 | Address addr; |
| 417 | |
| 418 | addr = codeloc(f); |
| 419 | while (linelookup(addr) == 0 and addr < objsize) { |
| 420 | ++addr; |
| 421 | } |
| 422 | if (addr == objsize) { |
| 423 | addr = -1; |
| 424 | } |
| 425 | return addr; |
| 426 | } |
| 427 | |
| 428 | /* |
| 429 | * Catcher drops strike three ... |
| 430 | */ |
| 431 | |
| 432 | public runtofirst() |
| 433 | { |
| 434 | Address addr; |
| 435 | |
| 436 | addr = pc; |
| 437 | while (linelookup(addr) == 0 and addr < objsize) { |
| 438 | ++addr; |
| 439 | } |
| 440 | if (addr < objsize) { |
| 441 | stepto(addr); |
| 442 | } |
| 443 | } |
| 444 | |
| 445 | /* |
| 446 | * Return the address corresponding to the end of the program. |
| 447 | * |
| 448 | * We look for the entry to "exit". |
| 449 | */ |
| 450 | |
| 451 | public Address lastaddr() |
| 452 | { |
| 453 | register Symbol s; |
| 454 | |
| 455 | s = lookup(identname("exit", true)); |
| 456 | if (s == nil) { |
| 457 | panic("can't find exit"); |
| 458 | } |
| 459 | return codeloc(s); |
| 460 | } |
| 461 | |
| 462 | /* |
| 463 | * Decide if the given function is currently active. |
| 464 | * |
| 465 | * We avoid calls to "findframe" during a stack trace for efficiency. |
| 466 | * Presumably information evaluated while walking the stack is active. |
| 467 | */ |
| 468 | |
| 469 | public Boolean isactive(f) |
| 470 | Symbol f; |
| 471 | { |
| 472 | register Boolean b; |
| 473 | |
| 474 | if (isfinished(process)) { |
| 475 | b = false; |
| 476 | } else { |
| 477 | if (walkingstack or f == program or |
| 478 | (ismodule(f) and isactive(container(f)))) { |
| 479 | b = true; |
| 480 | } else { |
| 481 | b = (Boolean) (findframe(f) != nil); |
| 482 | } |
| 483 | } |
| 484 | return b; |
| 485 | } |
| 486 | |
| 487 | /* |
| 488 | * Evaluate a call to a procedure. |
| 489 | */ |
| 490 | |
| 491 | public callproc(procnode, arglist) |
| 492 | Node procnode; |
| 493 | Node arglist; |
| 494 | { |
| 495 | Symbol proc; |
| 496 | Integer argc; |
| 497 | |
| 498 | if (procnode->op != O_SYM) { |
| 499 | beginerrmsg(); |
| 500 | fprintf(stderr, "can't call \""); |
| 501 | prtree(stderr, procnode); |
| 502 | fprintf(stderr, "\""); |
| 503 | enderrmsg(); |
| 504 | } |
| 505 | assert(procnode->op == O_SYM); |
| 506 | proc = procnode->value.sym; |
| 507 | if (not isblock(proc)) { |
| 508 | error("\"%s\" is not a procedure or function", symname(proc)); |
| 509 | } |
| 510 | pushenv(); |
| 511 | pc = codeloc(proc); |
| 512 | argc = pushargs(proc, arglist); |
| 513 | beginproc(proc, argc); |
| 514 | isstopped = true; |
| 515 | event_once(build(O_EQ, build(O_SYM, pcsym), build(O_SYM, retaddrsym)), |
| 516 | buildcmdlist(build(O_PROCRTN, proc))); |
| 517 | cont(); |
| 518 | /* NOTREACHED */ |
| 519 | } |
| 520 | |
| 521 | /* |
| 522 | * Push the arguments on the process' stack. We do this by first |
| 523 | * evaluating them on the "eval" stack, then copying into the process' |
| 524 | * space. |
| 525 | */ |
| 526 | |
| 527 | private Integer pushargs(proc, arglist) |
| 528 | Symbol proc; |
| 529 | Node arglist; |
| 530 | { |
| 531 | Stack *savesp; |
| 532 | int argc, args_size; |
| 533 | |
| 534 | savesp = sp; |
| 535 | argc = evalargs(proc, arglist); |
| 536 | args_size = sp - savesp; |
| 537 | setreg(STKP, reg(STKP) - args_size); |
| 538 | dwrite(savesp, reg(STKP), args_size); |
| 539 | sp = savesp; |
| 540 | return argc; |
| 541 | } |
| 542 | |
| 543 | /* |
| 544 | * Evaluate arguments left-to-right. |
| 545 | */ |
| 546 | |
| 547 | private Integer evalargs(proc, arglist) |
| 548 | Symbol proc; |
| 549 | Node arglist; |
| 550 | { |
| 551 | Node p, exp; |
| 552 | Symbol arg; |
| 553 | Stack *savesp; |
| 554 | Address addr; |
| 555 | Integer count; |
| 556 | |
| 557 | savesp = sp; |
| 558 | count = 0; |
| 559 | arg = proc->chain; |
| 560 | for (p = arglist; p != nil; p = p->value.arg[1]) { |
| 561 | if (p->op != O_COMMA) { |
| 562 | panic("evalargs: arglist missing comma"); |
| 563 | } |
| 564 | if (arg == nil) { |
| 565 | sp = savesp; |
| 566 | error("too many parameters to %s", symname(proc)); |
| 567 | } |
| 568 | exp = p->value.arg[0]; |
| 569 | if (not compatible(arg->type, exp->nodetype)) { |
| 570 | sp = savesp; |
| 571 | error("expression for parameter %s is of wrong type", symname(arg)); |
| 572 | } |
| 573 | if (arg->class == REF) { |
| 574 | if (exp->op != O_RVAL) { |
| 575 | sp = savesp; |
| 576 | error("variable expected for parameter \"%s\"", symname(arg)); |
| 577 | } |
| 578 | addr = lval(exp->value.arg[0]); |
| 579 | push(Address, addr); |
| 580 | } else { |
| 581 | eval(exp); |
| 582 | } |
| 583 | arg = arg->chain; |
| 584 | ++count; |
| 585 | } |
| 586 | if (arg != nil) { |
| 587 | sp = savesp; |
| 588 | error("not enough parameters to %s", symname(proc)); |
| 589 | } |
| 590 | return count; |
| 591 | } |
| 592 | |
| 593 | public procreturn(f) |
| 594 | Symbol f; |
| 595 | { |
| 596 | flushoutput(); |
| 597 | putchar('\n'); |
| 598 | printname(stdout, f); |
| 599 | printf(" returns successfully\n", symname(f)); |
| 600 | popenv(); |
| 601 | erecover(); |
| 602 | } |
| 603 | |
| 604 | /* |
| 605 | * Push the current environment. |
| 606 | */ |
| 607 | |
| 608 | private pushenv() |
| 609 | { |
| 610 | push(Address, pc); |
| 611 | push(Lineno, curline); |
| 612 | push(String, cursource); |
| 613 | push(Boolean, isstopped); |
| 614 | push(Symbol, curfunc); |
| 615 | push(Word, reg(PROGCTR)); |
| 616 | push(Word, reg(STKP)); |
| 617 | } |
| 618 | |
| 619 | /* |
| 620 | * Pop back to the real world. |
| 621 | */ |
| 622 | |
| 623 | public popenv() |
| 624 | { |
| 625 | register String filename; |
| 626 | |
| 627 | setreg(STKP, pop(Word)); |
| 628 | setreg(PROGCTR, pop(Word)); |
| 629 | curfunc = pop(Symbol); |
| 630 | isstopped = pop(Boolean); |
| 631 | filename = pop(String); |
| 632 | curline = pop(Lineno); |
| 633 | pc = pop(Address); |
| 634 | setsource(filename); |
| 635 | } |
| 636 | |
| 637 | /* |
| 638 | * Flush the debuggee's standard output. |
| 639 | * |
| 640 | * This is VERY dependent on the use of stdio. |
| 641 | */ |
| 642 | |
| 643 | public flushoutput() |
| 644 | { |
| 645 | register Symbol p, iob; |
| 646 | register Stack *savesp; |
| 647 | |
| 648 | p = lookup(identname("fflush", true)); |
| 649 | while (p != nil and not isblock(p)) { |
| 650 | p = p->next_sym; |
| 651 | } |
| 652 | if (p != nil) { |
| 653 | iob = lookup(identname("_iob", true)); |
| 654 | if (iob != nil) { |
| 655 | pushenv(); |
| 656 | pc = codeloc(p); |
| 657 | savesp = sp; |
| 658 | push(long, address(iob, nil) + sizeof(struct _iobuf)); |
| 659 | setreg(STKP, reg(STKP) - sizeof(long)); |
| 660 | dwrite(savesp, reg(STKP), sizeof(long)); |
| 661 | sp = savesp; |
| 662 | beginproc(p, 1); |
| 663 | stepto(return_addr()); |
| 664 | popenv(); |
| 665 | } |
| 666 | } |
| 667 | } |