comparison src/eval.c @ 617:af57a77cbc92

[xemacs-hg @ 2001-06-18 07:09:50 by ben] --------------------------------------------------------------- DOCUMENTATION FIXES: --------------------------------------------------------------- eval.c: Correct documentation. elhash.c: Doc correction. --------------------------------------------------------------- LISP OBJECT CLEANUP: --------------------------------------------------------------- bytecode.h, buffer.h, casetab.h, chartab.h, console-msw.h, console.h, database.c, device.h, eldap.h, elhash.h, events.h, extents.h, faces.h, file-coding.h, frame.h, glyphs.h, gui-x.h, gui.h, keymap.h, lisp-disunion.h, lisp-union.h, lisp.h, lrecord.h, lstream.h, mule-charset.h, objects.h, opaque.h, postgresql.h, process.h, rangetab.h, specifier.h, toolbar.h, tooltalk.h, ui-gtk.h: Add wrap_* to all objects (it was already there for a few of them) -- an expression to encapsulate a pointer into a Lisp object, rather than the inconvenient XSET*. "wrap" was chosen because "make" as in make_int(), make_char() is not appropriate. (It implies allocation. The issue does not exist for ints and chars because they are not allocated.) Full error checking has been added to these expressions. When used without error checking, non-union build, use of these expressions will incur no loss of efficiency. (In fact, XSET* is now defined in terms of wrap_* in a non-union build.) In a union build, you will also get no loss of efficiency provided that you have a decent optimizing compiler, and a compiler that either understands inlines or automatically inlines those particular functions. (And since people don't normally do their production builds on union, it doesn't matter.) Update the sample Lisp object definition in lrecord.h accordingly. dumper.c: Fix places in dumper that referenced wrap_object to reference its new name, wrap_pointer_1. buffer.c, bufslots.h, conslots.h, console.c, console.h, devslots.h, device.c, device.h, frame.c, frame.h, frameslots.h, window.c, window.h, winslots.h: -- Extract out the Lisp objects of `struct device' into devslots.h, just like for the other structures. -- Extract out the remaining (not copied into the window config) Lisp objects in `struct window' into winslots.h; use different macros (WINDOW_SLOT vs. WINDOW_SAVED_SLOT) to differentiate them. -- Eliminate the `dead' flag of `struct frame', since it duplicates information already available in `framemeths', and fix FRAME_LIVE_P accordingly. (Devices and consoles already work this way.) -- In *slots.h, switch to system where MARKED_SLOT is automatically undef'd at the end of the file. (Follows what winslots.h already does.) -- Update the comments at the beginning of *slots.h to be accurate. -- When making any of the above objects dead, zero it out entirely and reset all Lisp object slots to Qnil. (We were already doing this somewhat, but not consistently.) This (1) Eliminates the possibility of extra objects hanging around that ought to be GC'd, (2) Causes an immediate crash if anyone tries to access a structure in one of these objects, (3) Ensures consistent behavior wrt dead objects. dialog-msw.c: Use internal_object_printer, since this object should not escape. --------------------------------------------------------------- FIXING A CRASH THAT I HIT ONCE (AND A RELATED BAD BEHAVIOR): --------------------------------------------------------------- eval.c: Fix up some comments about the FSF implementation. Fix two nasty bugs: (1) condition_case_unwind frees the conses sitting in the catch->tag slot too quickly, resulting in a crash that I hit. (2) catches need to be unwound one at a time when calling unwind-protect code, rather than all at once at the end; otherwise, incorrect behavior can result. (A comment shows exactly how.) backtrace.h: Improve comment about FSF differences in the handler stack. --------------------------------------------------------------- FIXING A CRASH THAT I REPEATEDLY HIT WHEN USING THE MOUSE WHEEL UNDER MSWINDOWS: --------------------------------------------------------------- Basic idea: My crash is due either to a dead, non-marked, GC-collected frame inside of a window mirror, or a prematurely freed window mirror. We need to mark the Lisp objects inside of window mirrors. Tracking the lifespan of window mirrors and scrollbar instances is extremely hard, and there may well be lurking bugs where such objects are freed too soon. The only safe way to fix these problems (and it fixes both problems at once) is to make both of these structures Lisp objects. lrecord.h, emacs.c, inline.c, scrollbar-gtk.c, scrollbar-msw.c, scrollbar-x.c, scrollbar.c, scrollbar.h, symsinit.h: Make scrollbar instances actual Lisp objects. Mark the window mirrors in them. inline.c needs to know about scrollbar.h now. Record the new type in lrecord.h. Fix up scrollbar-*.c appropriately. Create a hash table in scrollbar-msw.c so that the scrollbar instances stored in scrollbar HWND's are properly GC-protected. Create complex_vars_of_scrollbar_mswindows() to create the hash table at startup, and call it from emacs.c. Don't store the scrollbar instance as a property of the GTK scrollbar, as it's not used and if we did this, we'd have to separately GC-protect it in a hash table, like in MS Windows. lrecord.h, frame.h, frame.c, frameslots.h, redisplay.c, window.c, window.h: Move mark_window_mirror from redisplay.c to window.c. Make window mirrors actual Lisp objects. Tell lrecord.h about them. Change the window mirror member of struct frame from a pointer to a Lisp object, and add XWINDOW_MIRROR in appropriate places. Mark the scrollbar instances in the window mirror. redisplay.c, redisplay.h, alloc.c: Delete mark_redisplay. Don't call mark_redisplay. We now mark frame-specific structures in mark_frame. NOTE: I also deleted an extremely questionable call to update_frame_window_mirrors(). It was extremely questionable before, and now totally impossible, since it will create Lisp objects during redisplay. frame.c: Mark the scrollbar instances, which are now Lisp objects. Call mark_gutter() here, not in mark_redisplay(). gutter.c: Update comments about correct marking. --------------------------------------------------------------- ISSUES BROUGHT UP BY MARTIN: --------------------------------------------------------------- buffer.h: Put back these macros the way Steve T and I think they ought to be. I already explained in a previous changelog entry why I think these macros should be the way I'd defined them. Once again: We fix these macros so they don't care about the type of their lvalues. The non-C-string equivalents of these already function in the same way, and it's correct because it should be OK to pass in a CBufbyte *, a BufByte *, a Char_Binary *, an UChar_Binary *, etc. The whole reason for these different types is to work around errors caused by signed-vs-unsigned non-matching types. Any possible error that might be caught in a DFC macro would also be caught wherever the argument is used elsewhere. So creating multiple macro versions would add no useful error-checking and just further complicate an already complicated area. As for Martin's "ANSI aliasing" bug, XEmacs is not ANSI-aliasing clean and probably never will be. Unless the board agrees to change XEmacs in this way (and we really don't want to go down that road), this is not a bug. sound.h: Undo Martin's type change. signal.c: Fix problem identified by Martin with Linux and g++ due to non-standard declaration of setitimer(). systime.h: Update the docs for "qxe_" to point out why making the encapsulation explicit is always the right way to go. (setitimer() itself serves as an example.) For 21.4: update-elc-2.el: Correct misplaced parentheses, making lisp/mule not get recompiled.
author ben
date Mon, 18 Jun 2001 07:10:32 +0000
parents 13e3d7ae7155
children b39c14581166
comparison
equal deleted inserted replaced
616:4f1c7a4ac1e6 617:af57a77cbc92
1341 This is used for correct unwinding in Fthrow and Fsignal. */ 1341 This is used for correct unwinding in Fthrow and Fsignal. */
1342 1342
1343 static void 1343 static void
1344 unwind_to_catch (struct catchtag *c, Lisp_Object val) 1344 unwind_to_catch (struct catchtag *c, Lisp_Object val)
1345 { 1345 {
1346 #if 0 /* FSFmacs */
1347 /* #### */
1348 REGISTER int last_time; 1346 REGISTER int last_time;
1349 #endif
1350 1347
1351 /* Unwind the specbind, catch, and handler stacks back to CATCH 1348 /* Unwind the specbind, catch, and handler stacks back to CATCH
1352 Before each catch is discarded, unbind all special bindings 1349 Before each catch is discarded, unbind all special bindings
1353 and execute all unwind-protect clauses made above that catch. 1350 and execute all unwind-protect clauses made above that catch.
1354 At the end, restore some static info saved in CATCH, 1351 At the end, restore some static info saved in CATCH,
1363 #if 0 /* FSFmacs */ 1360 #if 0 /* FSFmacs */
1364 /* Restore the polling-suppression count. */ 1361 /* Restore the polling-suppression count. */
1365 set_poll_suppress_count (catch->poll_suppress_count); 1362 set_poll_suppress_count (catch->poll_suppress_count);
1366 #endif 1363 #endif
1367 1364
1368 #if 0 /* FSFmacs */ 1365 #if 1
1369 /* #### FSFmacs has the following loop. Is it more correct? */
1370 do 1366 do
1371 { 1367 {
1372 last_time = catchlist == c; 1368 last_time = catchlist == c;
1373 1369
1374 /* Unwind the specpdl stack, and then restore the proper set of 1370 /* Unwind the specpdl stack, and then restore the proper set of
1375 handlers. */ 1371 handlers. */
1376 unbind_to (catchlist->pdlcount, Qnil); 1372 unbind_to (catchlist->pdlcount, Qnil);
1377 handlerlist = catchlist->handlerlist;
1378 catchlist = catchlist->next; 1373 catchlist = catchlist->next;
1379 #ifdef ERROR_CHECK_TYPECHECK 1374 #ifdef ERROR_CHECK_TYPECHECK
1380 check_error_state_sanity (); 1375 check_error_state_sanity ();
1381 #endif 1376 #endif
1382 } 1377 }
1383 while (! last_time); 1378 while (! last_time);
1384 #else /* Actual XEmacs code */ 1379 #else
1380 /* Former XEmacs code. This is definitely not as correct because
1381 there may be a number of catches we're unwinding, and a number
1382 of unwind-protects in the process. By not undoing the catches till
1383 the end, there may be invalid catches still current. (This would
1384 be a particular problem with code like this:
1385
1386 (catch 'foo
1387 (call-some-code-which-does...
1388 (catch 'bar
1389 (unwind-protect
1390 (call-some-code-which-does...
1391 (catch 'bar
1392 (call-some-code-which-does...
1393 (throw 'foo nil))))
1394 (throw 'bar nil)))))
1395
1396 This would try to throw to the inner (catch 'bar)!
1397
1398 --ben
1399 */
1385 /* Unwind the specpdl stack */ 1400 /* Unwind the specpdl stack */
1386 unbind_to (c->pdlcount, Qnil); 1401 unbind_to (c->pdlcount, Qnil);
1387 catchlist = c->next; 1402 catchlist = c->next;
1388 #ifdef ERROR_CHECK_TYPECHECK 1403 #ifdef ERROR_CHECK_TYPECHECK
1389 check_error_state_sanity (); 1404 check_error_state_sanity ();
1390 #endif 1405 #endif
1391 #endif 1406 #endif /* Former code */
1392 1407
1393 gcprolist = c->gcpro; 1408 gcprolist = c->gcpro;
1394 backtrace_list = c->backlist; 1409 backtrace_list = c->backlist;
1395 lisp_eval_depth = c->lisp_eval_depth; 1410 lisp_eval_depth = c->lisp_eval_depth;
1396 1411
1502 /************************************************************************/ 1517 /************************************************************************/
1503 1518
1504 static Lisp_Object 1519 static Lisp_Object
1505 condition_bind_unwind (Lisp_Object loser) 1520 condition_bind_unwind (Lisp_Object loser)
1506 { 1521 {
1522 /* There is no problem freeing stuff here like there is in
1523 condition_case_unwind(), because there are no outside pointers
1524 (like the tag below in the catchlist) pointing to the objects. */
1507 Lisp_Cons *victim; 1525 Lisp_Cons *victim;
1508 /* ((handler-fun . handler-args) ... other handlers) */ 1526 /* ((handler-fun . handler-args) ... other handlers) */
1509 Lisp_Object tem = XCAR (loser); 1527 Lisp_Object tem = XCAR (loser);
1510 1528
1511 while (CONSP (tem)) 1529 while (CONSP (tem))
1524 } 1542 }
1525 1543
1526 static Lisp_Object 1544 static Lisp_Object
1527 condition_case_unwind (Lisp_Object loser) 1545 condition_case_unwind (Lisp_Object loser)
1528 { 1546 {
1529 Lisp_Cons *victim;
1530
1531 /* ((<unbound> . clauses) ... other handlers */ 1547 /* ((<unbound> . clauses) ... other handlers */
1532 victim = XCONS (XCAR (loser)); 1548 /* NO! Doing this now leaves the tag deleted in a still-active
1533 free_cons (victim); 1549 catch. With the recent changes to unwind_to_catch(), the
1534 1550 evil situation might not happen any more; it certainly could
1535 victim = XCONS (loser); 1551 happen before because it did. But it's very precarious to rely
1552 on something like this. #### Instead we should rewrite, adopting
1553 the FSF's mechanism with a struct handler instead of
1554 Vcondition_handlers; then we have NO Lisp-object structures used
1555 to hold all of the values, and there's no possibility either of
1556 crashes from freeing objects too quickly, or objects not getting
1557 freed and hanging around till the next GC.
1558
1559 In practice, the extra consing here should not matter because
1560 it only happens when we throw past the condition-case, which almost
1561 always is the result of an error. Most of the time, there will be
1562 no error, and we will free the objects below in the main function.
1563
1564 --ben
1565
1566 DO NOT DO: free_cons (XCAR (loser));
1567 */
1568
1536 if (EQ (loser, Vcondition_handlers)) /* may have been rebound to some tail */ 1569 if (EQ (loser, Vcondition_handlers)) /* may have been rebound to some tail */
1537 Vcondition_handlers = victim->cdr; 1570 Vcondition_handlers = XCDR (loser);
1538 1571
1539 free_cons (victim); 1572 /* DO NOT DO: free_cons (loser); */
1540 return Qnil; 1573 return Qnil;
1541 } 1574 }
1542 1575
1543 /* Split out from condition_case_3 so that primitive C callers 1576 /* Split out from condition_case_3 so that primitive C callers
1544 don't have to cons up a lisp handler form to be evaluated. */ 1577 don't have to cons up a lisp handler form to be evaluated. */
1597 Lisp_Object (*hfun) (Lisp_Object val, Lisp_Object harg), 1630 Lisp_Object (*hfun) (Lisp_Object val, Lisp_Object harg),
1598 Lisp_Object harg) 1631 Lisp_Object harg)
1599 { 1632 {
1600 int speccount = specpdl_depth(); 1633 int speccount = specpdl_depth();
1601 struct catchtag c; 1634 struct catchtag c;
1602 struct gcpro gcpro1; 1635 struct gcpro gcpro1, gcpro2, gcpro3;
1603 1636
1604 #if 0 /* FSFmacs */ 1637 #if 0 /* FSFmacs */
1605 c.tag = Qnil; 1638 c.tag = Qnil;
1606 #else 1639 #else
1607 /* Do consing now so out-of-memory error happens up front */ 1640 /* Do consing now so out-of-memory error happens up front */
1608 /* (unbound . stuff) is a special condition-case kludge marker 1641 /* (unbound . stuff) is a special condition-case kludge marker
1609 which is known specially by Fsignal. 1642 which is known specially by Fsignal.
1610 This is an abomination, but to fix it would require either 1643 [[ This is an abomination, but to fix it would require either
1611 making condition_case cons (a union of the conditions of the clauses) 1644 making condition_case cons (a union of the conditions of the clauses)
1612 or changing the byte-compiler output (no thanks). */ 1645 or changing the byte-compiler output (no thanks).]]
1646
1647 The above comment is clearly wrong. FSF does not do it this way
1648 and did not change the byte-compiler output. Instead they use a
1649 `struct handler' to hold the various values (in place of our
1650 Vcondition_handlers) and chain them together, with pointers from
1651 the `struct catchtag' to the `struct handler'. We should perhaps
1652 consider moving to something similar, but not before I merge my
1653 stderr-proc workspace, which contains changes to these
1654 functions. --ben */
1613 c.tag = noseeum_cons (noseeum_cons (Qunbound, handlers), 1655 c.tag = noseeum_cons (noseeum_cons (Qunbound, handlers),
1614 Vcondition_handlers); 1656 Vcondition_handlers);
1615 #endif 1657 #endif
1616 c.val = Qnil; 1658 c.val = Qnil;
1617 c.backlist = backtrace_list; 1659 c.backlist = backtrace_list;
1645 handlerlist = &h; 1687 handlerlist = &h;
1646 #else 1688 #else
1647 Vcondition_handlers = c.tag; 1689 Vcondition_handlers = c.tag;
1648 #endif 1690 #endif
1649 GCPRO1 (harg); /* Somebody has to gc-protect */ 1691 GCPRO1 (harg); /* Somebody has to gc-protect */
1650
1651 c.val = ((*bfun) (barg)); 1692 c.val = ((*bfun) (barg));
1652
1653 /* The following is *not* true: (ben)
1654
1655 ungcpro, restoring catchlist and condition_handlers are actually
1656 redundant since unbind_to now restores them. But it looks funny not to
1657 have this code here, and it doesn't cost anything, so I'm leaving it.*/
1658 UNGCPRO; 1693 UNGCPRO;
1694
1695 /* Once we change `catchlist' below, the stuff in c will not be GCPRO'd. */
1696 GCPRO3 (harg, c.val, c.tag);
1697
1659 catchlist = c.next; 1698 catchlist = c.next;
1660 #ifdef ERROR_CHECK_TYPECHECK 1699 #ifdef ERROR_CHECK_TYPECHECK
1661 check_error_state_sanity (); 1700 check_error_state_sanity ();
1662 #endif 1701 #endif
1702 /* Note: The unbind also resets Vcondition_handlers. Maybe we should
1703 delete this here. */
1663 Vcondition_handlers = XCDR (c.tag); 1704 Vcondition_handlers = XCDR (c.tag);
1664 1705 unbind_to (speccount, Qnil);
1665 return unbind_to (speccount, c.val); 1706
1707 UNGCPRO;
1708 /* free the conses *after* the unbind, because the unbind will run
1709 condition_case_unwind above. */
1710 free_cons (XCONS (XCAR (c.tag)));
1711 free_cons (XCONS (c.tag));
1712 return c.val;
1666 } 1713 }
1667 1714
1668 static Lisp_Object 1715 static Lisp_Object
1669 run_condition_case_handlers (Lisp_Object val, Lisp_Object var) 1716 run_condition_case_handlers (Lisp_Object val, Lisp_Object var)
1670 { 1717 {
3601 return make_int (argcount); 3648 return make_int (argcount);
3602 } 3649 }
3603 } 3650 }
3604 3651
3605 DEFUN ("function-min-args", Ffunction_min_args, 1, 1, 0, /* 3652 DEFUN ("function-min-args", Ffunction_min_args, 1, 1, 0, /*
3606 Return the number of arguments a function may be called with. 3653 Return the minimum number of arguments a function may be called with.
3607 The function may be any form that can be passed to `funcall', 3654 The function may be any form that can be passed to `funcall',
3608 any special form, or any macro. 3655 any special form, or any macro.
3609 */ 3656 */
3610 (function)) 3657 (function))
3611 { 3658 {
3612 return function_argcount (function, 1); 3659 return function_argcount (function, 1);
3613 } 3660 }
3614 3661
3615 DEFUN ("function-max-args", Ffunction_max_args, 1, 1, 0, /* 3662 DEFUN ("function-max-args", Ffunction_max_args, 1, 1, 0, /*
3616 Return the number of arguments a function may be called with. 3663 Return the maximum number of arguments a function may be called with.
3617 The function may be any form that can be passed to `funcall', 3664 The function may be any form that can be passed to `funcall',
3618 any special form, or any macro. 3665 any special form, or any macro.
3619 If the function takes an arbitrary number of arguments or is 3666 If the function takes an arbitrary number of arguments or is
3620 a built-in special form, nil is returned. 3667 a built-in special form, nil is returned.
3621 */ 3668 */