Commit | Line | Data |
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52646e6f ML |
1 | /* Copyright (c) 1982 Regents of the University of California */ |
2 | ||
91df78fa | 3 | static char sccsid[] = "@(#)runtime.c 1.3 %G%"; |
52646e6f ML |
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); | |
91df78fa | 311 | line = srcline(frp->save_pc - 1); |
52646e6f ML |
312 | if (line != 0) { |
313 | printf(", line %d", line); | |
91df78fa | 314 | printf(" in \"%s\"\n", srcfilename(frp->save_pc - 1)); |
52646e6f ML |
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 | } |