| 1 | /* Copyright (c) 1982 Regents of the University of California */ |
| 2 | |
| 3 | static char sccsid[] = "@(#)runtime.c 1.3 %G%"; |
| 4 | |
| 5 | /* |
| 6 | * Runtime organization dependent routines, mostly dealing with |
| 7 | * activation records. |
| 8 | */ |
| 9 | |
| 10 | #include "defs.h" |
| 11 | #include "runtime.h" |
| 12 | #include "process.h" |
| 13 | #include "machine.h" |
| 14 | #include "events.h" |
| 15 | #include "mappings.h" |
| 16 | #include "symbols.h" |
| 17 | #include "tree.h" |
| 18 | #include "eval.h" |
| 19 | #include "operators.h" |
| 20 | #include "object.h" |
| 21 | |
| 22 | #ifndef public |
| 23 | typedef struct Frame *Frame; |
| 24 | |
| 25 | #include "machine.h" |
| 26 | #endif |
| 27 | |
| 28 | #define NSAVEREG 12 |
| 29 | |
| 30 | struct Frame { |
| 31 | Integer condition_handler; |
| 32 | Integer mask; |
| 33 | Address save_ap; /* argument pointer */ |
| 34 | Address save_fp; /* frame pointer */ |
| 35 | Address save_pc; /* program counter */ |
| 36 | Word save_reg[NSAVEREG]; /* not necessarily there */ |
| 37 | }; |
| 38 | |
| 39 | private Boolean walkingstack = false; |
| 40 | |
| 41 | /* |
| 42 | * Set a frame to the current activation record. |
| 43 | */ |
| 44 | |
| 45 | private getcurframe(frp) |
| 46 | register Frame frp; |
| 47 | { |
| 48 | register int i; |
| 49 | |
| 50 | checkref(frp); |
| 51 | frp->mask = reg(NREG); |
| 52 | frp->save_ap = reg(ARGP); |
| 53 | frp->save_fp = reg(FRP); |
| 54 | frp->save_pc = reg(PROGCTR); |
| 55 | for (i = 0; i < NSAVEREG; i++) { |
| 56 | frp->save_reg[i] = reg(i); |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | /* |
| 61 | * Return a pointer to the next activation record up the stack. |
| 62 | * Return nil if there is none. |
| 63 | * Writes over space pointed to by given argument. |
| 64 | */ |
| 65 | |
| 66 | #define bis(b, n) ((b & (1 << (n))) != 0) |
| 67 | |
| 68 | private Frame nextframe(frp) |
| 69 | Frame frp; |
| 70 | { |
| 71 | register Frame newfrp; |
| 72 | struct Frame frame; |
| 73 | register Integer i, j, mask; |
| 74 | |
| 75 | newfrp = frp; |
| 76 | dread(&frame, newfrp->save_fp, sizeof(struct Frame)); |
| 77 | if (frame.save_fp == nil) { |
| 78 | newfrp = nil; |
| 79 | } else { |
| 80 | mask = ((frame.mask >> 16) & 0x0fff); |
| 81 | j = 0; |
| 82 | for (i = 0; i < NSAVEREG; i++) { |
| 83 | if (bis(mask, i)) { |
| 84 | newfrp->save_reg[i] = frame.save_reg[j]; |
| 85 | ++j; |
| 86 | } |
| 87 | } |
| 88 | newfrp->condition_handler = frame.condition_handler; |
| 89 | newfrp->mask = mask; |
| 90 | newfrp->save_ap = frame.save_ap; |
| 91 | newfrp->save_fp = frame.save_fp; |
| 92 | newfrp->save_pc = frame.save_pc; |
| 93 | } |
| 94 | return newfrp; |
| 95 | } |
| 96 | |
| 97 | /* |
| 98 | * Return the frame associated with the given function. |
| 99 | * If the function is nil, return the most recently activated frame. |
| 100 | * |
| 101 | * Static allocation for the frame. |
| 102 | */ |
| 103 | |
| 104 | public Frame findframe(f) |
| 105 | Symbol f; |
| 106 | { |
| 107 | register Frame frp; |
| 108 | static struct Frame frame; |
| 109 | |
| 110 | frp = &frame; |
| 111 | getcurframe(frp); |
| 112 | if (f != nil) { |
| 113 | while (frp != nil and whatblock(frp->save_pc) != f) { |
| 114 | frp = nextframe(frp); |
| 115 | } |
| 116 | } |
| 117 | return frp; |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * Find the return address of the current procedure/function. |
| 122 | */ |
| 123 | |
| 124 | public Address return_addr() |
| 125 | { |
| 126 | Frame frp; |
| 127 | Address addr; |
| 128 | struct Frame frame; |
| 129 | |
| 130 | frp = &frame; |
| 131 | getcurframe(frp); |
| 132 | frp = nextframe(frp); |
| 133 | if (frp == nil) { |
| 134 | addr = 0; |
| 135 | } else { |
| 136 | addr = frp->save_pc; |
| 137 | } |
| 138 | return addr; |
| 139 | } |
| 140 | |
| 141 | /* |
| 142 | * Push the value associated with the current function. |
| 143 | */ |
| 144 | |
| 145 | public pushretval(len, isindirect) |
| 146 | Integer len; |
| 147 | Boolean isindirect; |
| 148 | { |
| 149 | Word r0; |
| 150 | |
| 151 | r0 = reg(0); |
| 152 | if (isindirect) { |
| 153 | rpush((Address) r0, len); |
| 154 | } else { |
| 155 | switch (len) { |
| 156 | case sizeof(char): |
| 157 | push(char, r0); |
| 158 | break; |
| 159 | |
| 160 | case sizeof(short): |
| 161 | push(short, r0); |
| 162 | break; |
| 163 | |
| 164 | default: |
| 165 | if (len == sizeof(Word)) { |
| 166 | push(Word, r0); |
| 167 | } else if (len == 2*sizeof(Word)) { |
| 168 | push(Word, r0); |
| 169 | push(Word, reg(1)); |
| 170 | } else { |
| 171 | panic("not indirect in pushretval?"); |
| 172 | } |
| 173 | break; |
| 174 | } |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * Return the base address for locals in the given frame. |
| 180 | */ |
| 181 | |
| 182 | public Address locals_base(frp) |
| 183 | register Frame frp; |
| 184 | { |
| 185 | return (frp == nil) ? reg(FRP) : frp->save_fp; |
| 186 | } |
| 187 | |
| 188 | /* |
| 189 | * Return the base address for arguments in the given frame. |
| 190 | */ |
| 191 | |
| 192 | public Address args_base(frp) |
| 193 | register Frame frp; |
| 194 | { |
| 195 | return (frp == nil) ? reg(ARGP) : frp->save_ap; |
| 196 | } |
| 197 | |
| 198 | /* |
| 199 | * Return saved register n from the given frame. |
| 200 | */ |
| 201 | |
| 202 | public Word savereg(n, frp) |
| 203 | register Integer n; |
| 204 | register Frame frp; |
| 205 | { |
| 206 | register Word w; |
| 207 | |
| 208 | if (frp == nil) { |
| 209 | w = reg(n); |
| 210 | } else { |
| 211 | switch (n) { |
| 212 | case ARGP: |
| 213 | w = frp->save_ap; |
| 214 | break; |
| 215 | |
| 216 | case FRP: |
| 217 | w = frp->save_fp; |
| 218 | break; |
| 219 | |
| 220 | case STKP: |
| 221 | w = reg(STKP); |
| 222 | break; |
| 223 | |
| 224 | case PROGCTR: |
| 225 | w = frp->save_pc; |
| 226 | break; |
| 227 | |
| 228 | default: |
| 229 | assert(n >= 0 and n < NSAVEREG); |
| 230 | w = frp->save_reg[n]; |
| 231 | break; |
| 232 | } |
| 233 | } |
| 234 | return w; |
| 235 | } |
| 236 | |
| 237 | /* |
| 238 | * Return the nth argument to the current procedure. |
| 239 | */ |
| 240 | |
| 241 | public Word argn(n, frp) |
| 242 | Integer n; |
| 243 | Frame frp; |
| 244 | { |
| 245 | Word w; |
| 246 | |
| 247 | dread(&w, args_base(frp) + (n * sizeof(Word)), sizeof(w)); |
| 248 | return w; |
| 249 | } |
| 250 | |
| 251 | /* |
| 252 | * Calculate the entry address for a procedure or function parameter, |
| 253 | * given the address of the descriptor. |
| 254 | */ |
| 255 | |
| 256 | public Address fparamaddr(a) |
| 257 | Address a; |
| 258 | { |
| 259 | Address r; |
| 260 | |
| 261 | dread(&r, a, sizeof(r)); |
| 262 | return r; |
| 263 | } |
| 264 | |
| 265 | /* |
| 266 | * Print a list of currently active blocks starting with most recent. |
| 267 | */ |
| 268 | |
| 269 | public wherecmd() |
| 270 | { |
| 271 | walkstack(false); |
| 272 | } |
| 273 | |
| 274 | /* |
| 275 | * Dump the world to the given file. |
| 276 | * Like "where", but variables are dumped also. |
| 277 | */ |
| 278 | |
| 279 | public dump() |
| 280 | { |
| 281 | walkstack(true); |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * Walk the stack of active procedures printing information |
| 286 | * about each active procedure. |
| 287 | */ |
| 288 | |
| 289 | #define lastfunc(f) (f == program) |
| 290 | |
| 291 | private walkstack(dumpvariables) |
| 292 | Boolean dumpvariables; |
| 293 | { |
| 294 | register Frame frp; |
| 295 | register Symbol f; |
| 296 | register Boolean save; |
| 297 | register Lineno line; |
| 298 | struct Frame frame; |
| 299 | |
| 300 | if (notstarted(process)) { |
| 301 | error("program is not active"); |
| 302 | } else { |
| 303 | save = walkingstack; |
| 304 | walkingstack = true; |
| 305 | frp = &frame; |
| 306 | getcurframe(frp); |
| 307 | f = whatblock(frp->save_pc); |
| 308 | do { |
| 309 | printf("%s", symname(f)); |
| 310 | printparams(f, frp); |
| 311 | line = srcline(frp->save_pc - 1); |
| 312 | if (line != 0) { |
| 313 | printf(", line %d", line); |
| 314 | printf(" in \"%s\"\n", srcfilename(frp->save_pc - 1)); |
| 315 | } else { |
| 316 | printf(" at 0x%x\n", frp->save_pc); |
| 317 | } |
| 318 | if (dumpvariables) { |
| 319 | dumpvars(f, frp); |
| 320 | putchar('\n'); |
| 321 | } |
| 322 | frp = nextframe(frp); |
| 323 | if (frp != nil) { |
| 324 | f = whatblock(frp->save_pc); |
| 325 | } |
| 326 | } while (frp != nil and not lastfunc(f)); |
| 327 | if (dumpvariables) { |
| 328 | printf("in \"%s\":\n", symname(program)); |
| 329 | dumpvars(program, nil); |
| 330 | putchar('\n'); |
| 331 | } |
| 332 | walkingstack = save; |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | /* |
| 337 | * Find the entry point of a procedure or function. |
| 338 | */ |
| 339 | |
| 340 | public findbeginning(f) |
| 341 | Symbol f; |
| 342 | { |
| 343 | f->symvalue.funcv.beginaddr += 2; |
| 344 | } |
| 345 | |
| 346 | /* |
| 347 | * Return the address corresponding to the first line in a function. |
| 348 | */ |
| 349 | |
| 350 | public Address firstline(f) |
| 351 | Symbol f; |
| 352 | { |
| 353 | Address addr; |
| 354 | |
| 355 | addr = codeloc(f); |
| 356 | while (linelookup(addr) == 0 and addr < objsize) { |
| 357 | ++addr; |
| 358 | } |
| 359 | if (addr == objsize) { |
| 360 | addr = -1; |
| 361 | } |
| 362 | return addr; |
| 363 | } |
| 364 | |
| 365 | /* |
| 366 | * Catcher drops strike three ... |
| 367 | */ |
| 368 | |
| 369 | public runtofirst() |
| 370 | { |
| 371 | Address addr; |
| 372 | |
| 373 | addr = pc; |
| 374 | while (linelookup(addr) == 0 and addr < objsize) { |
| 375 | ++addr; |
| 376 | } |
| 377 | if (addr < objsize) { |
| 378 | stepto(addr); |
| 379 | } |
| 380 | } |
| 381 | |
| 382 | /* |
| 383 | * Return the address corresponding to the end of the program. |
| 384 | * |
| 385 | * We look for the entry to "exit". |
| 386 | */ |
| 387 | |
| 388 | public Address lastaddr() |
| 389 | { |
| 390 | register Symbol s; |
| 391 | |
| 392 | s = lookup(identname("exit", true)); |
| 393 | if (s == nil) { |
| 394 | panic("can't find exit"); |
| 395 | } |
| 396 | return codeloc(s); |
| 397 | } |
| 398 | |
| 399 | /* |
| 400 | * Decide if the given function is currently active. |
| 401 | * |
| 402 | * We avoid calls to "findframe" during a stack trace for efficiency. |
| 403 | * Presumably information evaluated while walking the stack is active. |
| 404 | */ |
| 405 | |
| 406 | public Boolean isactive(f) |
| 407 | Symbol f; |
| 408 | { |
| 409 | register Boolean b; |
| 410 | |
| 411 | if (isfinished(process)) { |
| 412 | b = false; |
| 413 | } else { |
| 414 | if (walkingstack or f == program or |
| 415 | (ismodule(f) and isactive(container(f)))) { |
| 416 | b = true; |
| 417 | } else { |
| 418 | b = (Boolean) (findframe(f) != nil); |
| 419 | } |
| 420 | } |
| 421 | return b; |
| 422 | } |
| 423 | |
| 424 | /* |
| 425 | * Evaluate a call to a procedure. |
| 426 | */ |
| 427 | |
| 428 | public callproc(procnode, arglist) |
| 429 | Node procnode; |
| 430 | Node arglist; |
| 431 | { |
| 432 | Symbol proc; |
| 433 | Integer argc; |
| 434 | |
| 435 | if (procnode->op != O_SYM) { |
| 436 | beginerrmsg(); |
| 437 | fprintf(stderr, "can't call \""); |
| 438 | prtree(stderr, procnode); |
| 439 | fprintf(stderr, "\""); |
| 440 | enderrmsg(); |
| 441 | } |
| 442 | assert(procnode->op == O_SYM); |
| 443 | proc = procnode->value.sym; |
| 444 | if (not isblock(proc)) { |
| 445 | error("\"%s\" is not a procedure or function", symname(proc)); |
| 446 | } |
| 447 | pushenv(); |
| 448 | pc = codeloc(proc); |
| 449 | argc = pushargs(proc, arglist); |
| 450 | beginproc(proc, argc); |
| 451 | isstopped = true; |
| 452 | event_once(build(O_EQ, build(O_SYM, pcsym), build(O_SYM, retaddrsym)), |
| 453 | buildcmdlist(build(O_PROCRTN, proc))); |
| 454 | cont(); |
| 455 | /* NOTREACHED */ |
| 456 | } |
| 457 | |
| 458 | /* |
| 459 | * Push the arguments on the process' stack. We do this by first |
| 460 | * evaluating them on the "eval" stack, then copying into the process' |
| 461 | * space. |
| 462 | */ |
| 463 | |
| 464 | private Integer pushargs(proc, arglist) |
| 465 | Symbol proc; |
| 466 | Node arglist; |
| 467 | { |
| 468 | Stack *savesp; |
| 469 | int argc, args_size; |
| 470 | |
| 471 | savesp = sp; |
| 472 | argc = evalargs(proc, arglist); |
| 473 | args_size = sp - savesp; |
| 474 | setreg(STKP, reg(STKP) - args_size); |
| 475 | dwrite(savesp, reg(STKP), args_size); |
| 476 | sp = savesp; |
| 477 | return argc; |
| 478 | } |
| 479 | |
| 480 | /* |
| 481 | * Evaluate arguments left-to-right. |
| 482 | */ |
| 483 | |
| 484 | private Integer evalargs(proc, arglist) |
| 485 | Symbol proc; |
| 486 | Node arglist; |
| 487 | { |
| 488 | Node p, exp; |
| 489 | Symbol arg; |
| 490 | Stack *savesp; |
| 491 | Address addr; |
| 492 | Integer count; |
| 493 | |
| 494 | savesp = sp; |
| 495 | count = 0; |
| 496 | arg = proc->chain; |
| 497 | for (p = arglist; p != nil; p = p->value.arg[1]) { |
| 498 | if (p->op != O_COMMA) { |
| 499 | panic("evalargs: arglist missing comma"); |
| 500 | } |
| 501 | if (arg == nil) { |
| 502 | sp = savesp; |
| 503 | error("too many parameters to %s", symname(proc)); |
| 504 | } |
| 505 | exp = p->value.arg[0]; |
| 506 | if (not compatible(arg->type, exp->nodetype)) { |
| 507 | sp = savesp; |
| 508 | error("expression for parameter %s is of wrong type", symname(arg)); |
| 509 | } |
| 510 | if (arg->class == REF) { |
| 511 | if (exp->op != O_RVAL) { |
| 512 | sp = savesp; |
| 513 | error("variable expected for parameter \"%s\"", symname(arg)); |
| 514 | } |
| 515 | addr = lval(exp->value.arg[0]); |
| 516 | push(Address, addr); |
| 517 | } else { |
| 518 | eval(exp); |
| 519 | } |
| 520 | arg = arg->chain; |
| 521 | ++count; |
| 522 | } |
| 523 | if (arg != nil) { |
| 524 | sp = savesp; |
| 525 | error("not enough parameters to %s", symname(proc)); |
| 526 | } |
| 527 | return count; |
| 528 | } |
| 529 | |
| 530 | public procreturn(f) |
| 531 | Symbol f; |
| 532 | { |
| 533 | flushoutput(); |
| 534 | putchar('\n'); |
| 535 | printname(stdout, f); |
| 536 | printf(" returns successfully\n", symname(f)); |
| 537 | popenv(); |
| 538 | erecover(); |
| 539 | } |
| 540 | |
| 541 | /* |
| 542 | * Push the current environment. |
| 543 | */ |
| 544 | |
| 545 | private pushenv() |
| 546 | { |
| 547 | push(Address, pc); |
| 548 | push(Lineno, curline); |
| 549 | push(String, cursource); |
| 550 | push(Boolean, isstopped); |
| 551 | push(Symbol, curfunc); |
| 552 | push(Word, reg(PROGCTR)); |
| 553 | push(Word, reg(STKP)); |
| 554 | } |
| 555 | |
| 556 | /* |
| 557 | * Pop back to the real world. |
| 558 | */ |
| 559 | |
| 560 | public popenv() |
| 561 | { |
| 562 | register String filename; |
| 563 | |
| 564 | setreg(STKP, pop(Word)); |
| 565 | setreg(PROGCTR, pop(Word)); |
| 566 | curfunc = pop(Symbol); |
| 567 | isstopped = pop(Boolean); |
| 568 | filename = pop(String); |
| 569 | curline = pop(Lineno); |
| 570 | pc = pop(Address); |
| 571 | setsource(filename); |
| 572 | } |
| 573 | |
| 574 | /* |
| 575 | * Flush the debuggee's standard output. |
| 576 | * |
| 577 | * This is VERY dependent on the use of stdio. |
| 578 | */ |
| 579 | |
| 580 | public flushoutput() |
| 581 | { |
| 582 | register Symbol p, iob; |
| 583 | register Stack *savesp; |
| 584 | |
| 585 | p = lookup(identname("fflush", true)); |
| 586 | while (p != nil and not isblock(p)) { |
| 587 | p = p->next_sym; |
| 588 | } |
| 589 | if (p != nil) { |
| 590 | iob = lookup(identname("_iob", true)); |
| 591 | if (iob != nil) { |
| 592 | pushenv(); |
| 593 | pc = codeloc(p); |
| 594 | savesp = sp; |
| 595 | push(long, address(iob, nil) + sizeof(struct _iobuf)); |
| 596 | setreg(STKP, reg(STKP) - sizeof(long)); |
| 597 | dwrite(savesp, reg(STKP), sizeof(long)); |
| 598 | sp = savesp; |
| 599 | beginproc(p, 1); |
| 600 | stepto(return_addr()); |
| 601 | popenv(); |
| 602 | } |
| 603 | } |
| 604 | } |