X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/a61dba1c5a5f32827eeda649c9421fc92d742a3d..e3060a0c4d2f418ac786775109d71e5843ccf42e:/src/eval.c diff --git a/src/eval.c b/src/eval.c index 6cb2b7a92b..77b1db9539 100644 --- a/src/eval.c +++ b/src/eval.c @@ -1,6 +1,7 @@ /* Evaluator for GNU Emacs Lisp interpreter. - Copyright (C) 1985-1987, 1993-1995, 1999-2013 Free Software - Foundation, Inc. + +Copyright (C) 1985-1987, 1993-1995, 1999-2014 Free Software Foundation, +Inc. This file is part of GNU Emacs. @@ -26,26 +27,9 @@ along with GNU Emacs. If not, see . */ #include "commands.h" #include "keyboard.h" #include "dispextern.h" -#include "frame.h" /* For XFRAME. */ - -#if HAVE_X_WINDOWS -#include "xterm.h" -#endif -#if !BYTE_MARK_STACK -static -#endif -struct catchtag *catchlist; +/* Chain of condition and catch handlers currently in effect. */ -/* Chain of condition handlers currently in effect. - The elements of this chain are contained in the stack frames - of Fcondition_case and internal_condition_case. - When an error is signaled (by calling Fsignal, below), - this chain is searched for an element that applies. */ - -#if !BYTE_MARK_STACK -static -#endif struct handler *handlerlist; #ifdef DEBUG_GCPRO @@ -92,7 +76,7 @@ union specbinding *specpdl_ptr; /* Depth in Lisp evaluations and function calls. */ -static EMACS_INT lisp_eval_depth; +EMACS_INT lisp_eval_depth; /* The value of num_nonmacro_input_events as of the last time we started to enter the debugger. If we decide to enter the debugger @@ -108,10 +92,8 @@ static EMACS_INT when_entered_debugger; /* FIXME: We should probably get rid of this! */ Lisp_Object Vsignaling_function; -/* If non-nil, Lisp code must not be run since some part of Emacs is - in an inconsistent state. Currently, x-create-frame uses this to - avoid triggering window-configuration-change-hook while the new - frame is half-initialized. */ +/* If non-nil, Lisp code must not be run since some part of Emacs is in + an inconsistent state. Currently unused. */ Lisp_Object inhibit_lisp_code; /* These would ordinarily be static, but they need to be visible to GDB. */ @@ -122,7 +104,7 @@ union specbinding *backtrace_next (union specbinding *) EXTERNALLY_VISIBLE; union specbinding *backtrace_top (void) EXTERNALLY_VISIBLE; static Lisp_Object funcall_lambda (Lisp_Object, ptrdiff_t, Lisp_Object *); -static Lisp_Object apply_lambda (Lisp_Object fun, Lisp_Object args); +static Lisp_Object apply_lambda (Lisp_Object, Lisp_Object, ptrdiff_t); static Lisp_Object specpdl_symbol (union specbinding *pdl) @@ -138,6 +120,13 @@ specpdl_old_value (union specbinding *pdl) return pdl->let.old_value; } +static void +set_specpdl_old_value (union specbinding *pdl, Lisp_Object val) +{ + eassert (pdl->kind >= SPECPDL_LET); + pdl->let.old_value = val; +} + static Lisp_Object specpdl_where (union specbinding *pdl) { @@ -183,17 +172,11 @@ backtrace_debug_on_exit (union specbinding *pdl) /* Functions to modify slots of backtrace records. */ static void -set_backtrace_args (union specbinding *pdl, Lisp_Object *args) +set_backtrace_args (union specbinding *pdl, Lisp_Object *args, ptrdiff_t nargs) { eassert (pdl->kind == SPECPDL_BACKTRACE); pdl->bt.args = args; -} - -static void -set_backtrace_nargs (union specbinding *pdl, ptrdiff_t n) -{ - eassert (pdl->kind == SPECPDL_BACKTRACE); - pdl->bt.nargs = n; + pdl->bt.nargs = nargs; } static void @@ -242,12 +225,22 @@ init_eval_once (void) Vrun_hooks = Qnil; } +static struct handler handlerlist_sentinel; + void init_eval (void) { specpdl_ptr = specpdl; - catchlist = 0; - handlerlist = 0; + { /* Put a dummy catcher at top-level so that handlerlist is never NULL. + This is important since handlerlist->nextfree holds the freelist + which would otherwise leak every time we unwind back to top-level. */ + struct handler *c; + handlerlist = handlerlist_sentinel.nextfree = &handlerlist_sentinel; + PUSH_HANDLER (c, Qunbound, CATCHER); + eassert (c == &handlerlist_sentinel); + handlerlist_sentinel.nextfree = NULL; + handlerlist_sentinel.next = NULL; + } Vquit_flag = Qnil; debug_on_next_call = 0; lisp_eval_depth = 0; @@ -267,6 +260,8 @@ restore_stack_limits (Lisp_Object data) max_lisp_eval_depth = XINT (XCDR (data)); } +static void grow_specpdl (void); + /* Call the Lisp debugger, giving it argument ARG. */ Lisp_Object @@ -275,22 +270,29 @@ call_debugger (Lisp_Object arg) bool debug_while_redisplaying; ptrdiff_t count = SPECPDL_INDEX (); Lisp_Object val; - EMACS_INT old_max = max_specpdl_size; - - /* Temporarily bump up the stack limits, - so the debugger won't run out of stack. */ - - max_specpdl_size += 1; - record_unwind_protect (restore_stack_limits, - Fcons (make_number (old_max), - make_number (max_lisp_eval_depth))); - max_specpdl_size = old_max; + EMACS_INT old_depth = max_lisp_eval_depth; + /* Do not allow max_specpdl_size less than actual depth (Bug#16603). */ + EMACS_INT old_max = max (max_specpdl_size, count); if (lisp_eval_depth + 40 > max_lisp_eval_depth) max_lisp_eval_depth = lisp_eval_depth + 40; - if (max_specpdl_size - 100 < SPECPDL_INDEX ()) - max_specpdl_size = SPECPDL_INDEX () + 100; + /* While debugging Bug#16603, previous value of 100 was found + too small to avoid specpdl overflow in the debugger itself. */ + if (max_specpdl_size - 200 < count) + max_specpdl_size = count + 200; + + if (old_max == count) + { + /* We can enter the debugger due to specpdl overflow (Bug#16603). */ + specpdl_ptr--; + grow_specpdl (); + } + + /* Restore limits after leaving the debugger. */ + record_unwind_protect (restore_stack_limits, + Fcons (make_number (old_max), + make_number (old_depth))); #ifdef HAVE_WINDOW_SYSTEM if (display_hourglass_p) @@ -326,10 +328,10 @@ call_debugger (Lisp_Object arg) } static void -do_debug_on_call (Lisp_Object code) +do_debug_on_call (Lisp_Object code, ptrdiff_t count) { debug_on_next_call = 0; - set_backtrace_debug_on_exit (specpdl_ptr - 1, true); + set_backtrace_debug_on_exit (specpdl + count, true); call_debugger (list1 (code)); } @@ -411,9 +413,9 @@ Each clause looks like (CONDITION BODY...). CONDITION is evaluated and, if the value is non-nil, this clause succeeds: then the expressions in BODY are evaluated and the last one's value is the value of the cond-form. +If a clause has one element, as in (CONDITION), then the cond-form +returns CONDITION's value, if that is non-nil. If no clause succeeds, cond returns nil. -If a clause has one element, as in (CONDITION), -CONDITION's value if non-nil is returned from the cond-form. usage: (cond CLAUSES...) */) (Lisp_Object args) { @@ -651,6 +653,51 @@ The return value is BASE-VARIABLE. */) return base_variable; } +static union specbinding * +default_toplevel_binding (Lisp_Object symbol) +{ + union specbinding *binding = NULL; + union specbinding *pdl = specpdl_ptr; + while (pdl > specpdl) + { + switch ((--pdl)->kind) + { + case SPECPDL_LET_DEFAULT: + case SPECPDL_LET: + if (EQ (specpdl_symbol (pdl), symbol)) + binding = pdl; + break; + } + } + return binding; +} + +DEFUN ("default-toplevel-value", Fdefault_toplevel_value, Sdefault_toplevel_value, 1, 1, 0, + doc: /* Return SYMBOL's toplevel default value. +"Toplevel" means outside of any let binding. */) + (Lisp_Object symbol) +{ + union specbinding *binding = default_toplevel_binding (symbol); + Lisp_Object value + = binding ? specpdl_old_value (binding) : Fdefault_value (symbol); + if (!EQ (value, Qunbound)) + return value; + xsignal1 (Qvoid_variable, symbol); +} + +DEFUN ("set-default-toplevel-value", Fset_default_toplevel_value, + Sset_default_toplevel_value, 2, 2, 0, + doc: /* Set SYMBOL's toplevel default value to VALUE. +"Toplevel" means outside of any let binding. */) + (Lisp_Object symbol, Lisp_Object value) +{ + union specbinding *binding = default_toplevel_binding (symbol); + if (binding) + set_specpdl_old_value (binding, value); + else + Fset_default (symbol, value); + return Qnil; +} DEFUN ("defvar", Fdefvar, Sdefvar, 1, UNEVALLED, 0, doc: /* Define SYMBOL as a variable, and return SYMBOL. @@ -699,18 +746,10 @@ usage: (defvar SYMBOL &optional INITVALUE DOCSTRING) */) else { /* Check if there is really a global binding rather than just a let binding that shadows the global unboundness of the var. */ - union specbinding *pdl = specpdl_ptr; - while (pdl > specpdl) + union specbinding *binding = default_toplevel_binding (sym); + if (binding && EQ (specpdl_old_value (binding), Qunbound)) { - if ((--pdl)->kind >= SPECPDL_LET - && EQ (specpdl_symbol (pdl), sym) - && EQ (specpdl_old_value (pdl), Qunbound)) - { - message_with_string - ("Warning: defvar ignored because %s is let-bound", - SYMBOL_NAME (sym), 1); - break; - } + set_specpdl_old_value (binding, eval_sub (XCAR (tail))); } } tail = XCDR (tail); @@ -1041,6 +1080,12 @@ usage: (catch TAG BODY...) */) return internal_catch (tag, Fprogn, XCDR (args)); } +/* Assert that E is true, as a comment only. Use this instead of + eassert (E) when E contains variables that might be clobbered by a + longjmp. */ + +#define clobbered_eassert(E) ((void) 0) + /* Set up a catch, then call C function FUNC on argument ARG. FUNC should return a Lisp_Object. This is how catches are done from within C code. */ @@ -1049,28 +1094,26 @@ Lisp_Object internal_catch (Lisp_Object tag, Lisp_Object (*func) (Lisp_Object), Lisp_Object arg) { /* This structure is made part of the chain `catchlist'. */ - struct catchtag c; + struct handler *c; /* Fill in the components of c, and put it on the list. */ - c.next = catchlist; - c.tag = tag; - c.val = Qnil; - c.handlerlist = handlerlist; - c.lisp_eval_depth = lisp_eval_depth; - c.pdlcount = SPECPDL_INDEX (); - c.poll_suppress_count = poll_suppress_count; - c.interrupt_input_blocked = interrupt_input_blocked; - c.gcpro = gcprolist; - c.byte_stack = byte_stack_list; - catchlist = &c; + PUSH_HANDLER (c, tag, CATCHER); /* Call FUNC. */ - if (! sys_setjmp (c.jmp)) - c.val = (*func) (arg); - - /* Throw works by a longjmp that comes right here. */ - catchlist = c.next; - return c.val; + if (! sys_setjmp (c->jmp)) + { + Lisp_Object val = (*func) (arg); + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; + return val; + } + else + { /* Throw works by a longjmp that comes right here. */ + Lisp_Object val = handlerlist->val; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; + return val; + } } /* Unwind the specbind, catch, and handler stacks back to CATCH, and @@ -1090,10 +1133,12 @@ internal_catch (Lisp_Object tag, Lisp_Object (*func) (Lisp_Object), Lisp_Object This is used for correct unwinding in Fthrow and Fsignal. */ static _Noreturn void -unwind_to_catch (struct catchtag *catch, Lisp_Object value) +unwind_to_catch (struct handler *catch, Lisp_Object value) { bool last_time; + eassert (catch->next); + /* Save the value in the tag. */ catch->val = value; @@ -1104,16 +1149,17 @@ unwind_to_catch (struct catchtag *catch, Lisp_Object value) do { - last_time = catchlist == catch; - /* Unwind the specpdl stack, and then restore the proper set of handlers. */ - unbind_to (catchlist->pdlcount, Qnil); - handlerlist = catchlist->handlerlist; - catchlist = catchlist->next; + unbind_to (handlerlist->pdlcount, Qnil); + last_time = handlerlist == catch; + if (! last_time) + handlerlist = handlerlist->next; } while (! last_time); + eassert (handlerlist == catch); + byte_stack_list = catch->byte_stack; gcprolist = catch->gcpro; #ifdef DEBUG_GCPRO @@ -1129,12 +1175,12 @@ DEFUN ("throw", Fthrow, Sthrow, 2, 2, 0, Both TAG and VALUE are evalled. */) (register Lisp_Object tag, Lisp_Object value) { - register struct catchtag *c; + struct handler *c; if (!NILP (tag)) - for (c = catchlist; c; c = c->next) + for (c = handlerlist; c; c = c->next) { - if (EQ (c->tag, tag)) + if (c->type == CATCHER && EQ (c->tag_or_ch, tag)) unwind_to_catch (c, value); } xsignal2 (Qno_catch, tag, value); @@ -1200,15 +1246,16 @@ internal_lisp_condition_case (volatile Lisp_Object var, Lisp_Object bodyform, Lisp_Object handlers) { Lisp_Object val; - struct catchtag c; - struct handler h; + struct handler *c; + struct handler *oldhandlerlist = handlerlist; + int clausenb = 0; CHECK_SYMBOL (var); for (val = handlers; CONSP (val); val = XCDR (val)) { - Lisp_Object tem; - tem = XCAR (val); + Lisp_Object tem = XCAR (val); + clausenb++; if (! (NILP (tem) || (CONSP (tem) && (SYMBOLP (XCAR (tem)) @@ -1217,39 +1264,54 @@ internal_lisp_condition_case (volatile Lisp_Object var, Lisp_Object bodyform, SDATA (Fprin1_to_string (tem, Qt))); } - c.tag = Qnil; - c.val = Qnil; - c.handlerlist = handlerlist; - c.lisp_eval_depth = lisp_eval_depth; - c.pdlcount = SPECPDL_INDEX (); - c.poll_suppress_count = poll_suppress_count; - c.interrupt_input_blocked = interrupt_input_blocked; - c.gcpro = gcprolist; - c.byte_stack = byte_stack_list; - if (sys_setjmp (c.jmp)) - { - if (!NILP (h.var)) - specbind (h.var, c.val); - val = Fprogn (Fcdr (h.chosen_clause)); - - /* Note that this just undoes the binding of h.var; whoever - longjumped to us unwound the stack to c.pdlcount before - throwing. */ - unbind_to (c.pdlcount, Qnil); - return val; - } - c.next = catchlist; - catchlist = &c; - - h.var = var; - h.handler = handlers; - h.next = handlerlist; - h.tag = &c; - handlerlist = &h; + { /* The first clause is the one that should be checked first, so it should + be added to handlerlist last. So we build in `clauses' a table that + contains `handlers' but in reverse order. SAFE_ALLOCA won't work + here due to the setjmp, so impose a MAX_ALLOCA limit. */ + if (MAX_ALLOCA / word_size < clausenb) + memory_full (SIZE_MAX); + Lisp_Object *clauses = alloca (clausenb * sizeof *clauses); + Lisp_Object *volatile clauses_volatile = clauses; + int i = clausenb; + for (val = handlers; CONSP (val); val = XCDR (val)) + clauses[--i] = XCAR (val); + for (i = 0; i < clausenb; i++) + { + Lisp_Object clause = clauses[i]; + Lisp_Object condition = XCAR (clause); + if (!CONSP (condition)) + condition = Fcons (condition, Qnil); + PUSH_HANDLER (c, condition, CONDITION_CASE); + if (sys_setjmp (c->jmp)) + { + ptrdiff_t count = SPECPDL_INDEX (); + Lisp_Object val = handlerlist->val; + Lisp_Object *chosen_clause = clauses_volatile; + for (c = handlerlist->next; c != oldhandlerlist; c = c->next) + chosen_clause++; + handlerlist = oldhandlerlist; + if (!NILP (var)) + { + if (!NILP (Vinternal_interpreter_environment)) + specbind (Qinternal_interpreter_environment, + Fcons (Fcons (var, val), + Vinternal_interpreter_environment)); + else + specbind (var, val); + } + val = Fprogn (XCDR (*chosen_clause)); + /* Note that this just undoes the binding of var; whoever + longjumped to us unwound the stack to c.pdlcount before + throwing. */ + if (!NILP (var)) + unbind_to (count, Qnil); + return val; + } + } + } val = eval_sub (bodyform); - catchlist = c.next; - handlerlist = h.next; + handlerlist = oldhandlerlist; return val; } @@ -1268,33 +1330,20 @@ internal_condition_case (Lisp_Object (*bfun) (void), Lisp_Object handlers, Lisp_Object (*hfun) (Lisp_Object)) { Lisp_Object val; - struct catchtag c; - struct handler h; - - c.tag = Qnil; - c.val = Qnil; - c.handlerlist = handlerlist; - c.lisp_eval_depth = lisp_eval_depth; - c.pdlcount = SPECPDL_INDEX (); - c.poll_suppress_count = poll_suppress_count; - c.interrupt_input_blocked = interrupt_input_blocked; - c.gcpro = gcprolist; - c.byte_stack = byte_stack_list; - if (sys_setjmp (c.jmp)) - { - return (*hfun) (c.val); - } - c.next = catchlist; - catchlist = &c; - h.handler = handlers; - h.var = Qnil; - h.next = handlerlist; - h.tag = &c; - handlerlist = &h; + struct handler *c; + + PUSH_HANDLER (c, handlers, CONDITION_CASE); + if (sys_setjmp (c->jmp)) + { + Lisp_Object val = handlerlist->val; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; + return (*hfun) (val); + } val = (*bfun) (); - catchlist = c.next; - handlerlist = h.next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } @@ -1305,33 +1354,20 @@ internal_condition_case_1 (Lisp_Object (*bfun) (Lisp_Object), Lisp_Object arg, Lisp_Object handlers, Lisp_Object (*hfun) (Lisp_Object)) { Lisp_Object val; - struct catchtag c; - struct handler h; - - c.tag = Qnil; - c.val = Qnil; - c.handlerlist = handlerlist; - c.lisp_eval_depth = lisp_eval_depth; - c.pdlcount = SPECPDL_INDEX (); - c.poll_suppress_count = poll_suppress_count; - c.interrupt_input_blocked = interrupt_input_blocked; - c.gcpro = gcprolist; - c.byte_stack = byte_stack_list; - if (sys_setjmp (c.jmp)) - { - return (*hfun) (c.val); - } - c.next = catchlist; - catchlist = &c; - h.handler = handlers; - h.var = Qnil; - h.next = handlerlist; - h.tag = &c; - handlerlist = &h; + struct handler *c; + + PUSH_HANDLER (c, handlers, CONDITION_CASE); + if (sys_setjmp (c->jmp)) + { + Lisp_Object val = handlerlist->val; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; + return (*hfun) (val); + } val = (*bfun) (arg); - catchlist = c.next; - handlerlist = h.next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } @@ -1346,33 +1382,20 @@ internal_condition_case_2 (Lisp_Object (*bfun) (Lisp_Object, Lisp_Object), Lisp_Object (*hfun) (Lisp_Object)) { Lisp_Object val; - struct catchtag c; - struct handler h; - - c.tag = Qnil; - c.val = Qnil; - c.handlerlist = handlerlist; - c.lisp_eval_depth = lisp_eval_depth; - c.pdlcount = SPECPDL_INDEX (); - c.poll_suppress_count = poll_suppress_count; - c.interrupt_input_blocked = interrupt_input_blocked; - c.gcpro = gcprolist; - c.byte_stack = byte_stack_list; - if (sys_setjmp (c.jmp)) - { - return (*hfun) (c.val); - } - c.next = catchlist; - catchlist = &c; - h.handler = handlers; - h.var = Qnil; - h.next = handlerlist; - h.tag = &c; - handlerlist = &h; + struct handler *c; + + PUSH_HANDLER (c, handlers, CONDITION_CASE); + if (sys_setjmp (c->jmp)) + { + Lisp_Object val = handlerlist->val; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; + return (*hfun) (val); + } val = (*bfun) (arg1, arg2); - catchlist = c.next; - handlerlist = h.next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } @@ -1389,33 +1412,20 @@ internal_condition_case_n (Lisp_Object (*bfun) (ptrdiff_t, Lisp_Object *), Lisp_Object *args)) { Lisp_Object val; - struct catchtag c; - struct handler h; - - c.tag = Qnil; - c.val = Qnil; - c.handlerlist = handlerlist; - c.lisp_eval_depth = lisp_eval_depth; - c.pdlcount = SPECPDL_INDEX (); - c.poll_suppress_count = poll_suppress_count; - c.interrupt_input_blocked = interrupt_input_blocked; - c.gcpro = gcprolist; - c.byte_stack = byte_stack_list; - if (sys_setjmp (c.jmp)) - { - return (*hfun) (c.val, nargs, args); - } - c.next = catchlist; - catchlist = &c; - h.handler = handlers; - h.var = Qnil; - h.next = handlerlist; - h.tag = &c; - handlerlist = &h; + struct handler *c; + + PUSH_HANDLER (c, handlers, CONDITION_CASE); + if (sys_setjmp (c->jmp)) + { + Lisp_Object val = handlerlist->val; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; + return (*hfun) (val, nargs, args); + } val = (*bfun) (nargs, args); - catchlist = c.next; - handlerlist = h.next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } @@ -1507,7 +1517,9 @@ See also the function `condition-case'. */) for (h = handlerlist; h; h = h->next) { - clause = find_handler_clause (h->handler, conditions); + if (h->type != CONDITION_CASE) + continue; + clause = find_handler_clause (h->tag_or_ch, conditions); if (!NILP (clause)) break; } @@ -1520,11 +1532,11 @@ See also the function `condition-case'. */) || NILP (clause) /* A `debug' symbol in the handler list disables the normal suppression of the debugger. */ - || (CONSP (clause) && CONSP (XCAR (clause)) - && !NILP (Fmemq (Qdebug, XCAR (clause)))) + || (CONSP (clause) && CONSP (clause) + && !NILP (Fmemq (Qdebug, clause))) /* Special handler that means "print a message and run debugger if requested". */ - || EQ (h->handler, Qerror))) + || EQ (h->tag_or_ch, Qerror))) { bool debugger_called = maybe_call_debugger (conditions, error_symbol, data); @@ -1539,12 +1551,14 @@ See also the function `condition-case'. */) Lisp_Object unwind_data = (NILP (error_symbol) ? data : Fcons (error_symbol, data)); - h->chosen_clause = clause; - unwind_to_catch (h->tag, unwind_data); + unwind_to_catch (h, unwind_data); } else { - if (catchlist != 0) + if (handlerlist != &handlerlist_sentinel) + /* FIXME: This will come right back here if there's no `top-level' + catcher. A better solution would be to abort here, and instead + add a catch-all condition handler so we never come here. */ Fthrow (Qtop_level, Qt); } @@ -1730,29 +1744,8 @@ find_handler_clause (Lisp_Object handlers, Lisp_Object conditions) for (h = handlers; CONSP (h); h = XCDR (h)) { Lisp_Object handler = XCAR (h); - Lisp_Object condit, tem; - - if (!CONSP (handler)) - continue; - condit = XCAR (handler); - /* Handle a single condition name in handler HANDLER. */ - if (SYMBOLP (condit)) - { - tem = Fmemq (Fcar (handler), conditions); - if (!NILP (tem)) - return handler; - } - /* Handle a list of condition names in handler HANDLER. */ - else if (CONSP (condit)) - { - Lisp_Object tail; - for (tail = condit; CONSP (tail); tail = XCDR (tail)) - { - tem = Fmemq (XCAR (tail), conditions); - if (!NILP (tem)) - return handler; - } - } + if (!NILP (Fmemq (handler, conditions))) + return handlers; } return Qnil; @@ -1989,7 +1982,9 @@ it is defines a macro. */) DEFUN ("eval", Feval, Seval, 1, 2, 0, doc: /* Evaluate FORM and return its value. -If LEXICAL is t, evaluate using lexical scoping. */) +If LEXICAL is t, evaluate using lexical scoping. +LEXICAL can also be an actual lexical environment, in the form of an +alist mapping symbols to their value. */) (Lisp_Object form, Lisp_Object lexical) { ptrdiff_t count = SPECPDL_INDEX (); @@ -2034,9 +2029,11 @@ grow_specpdl (void) } } -void +ptrdiff_t record_in_backtrace (Lisp_Object function, Lisp_Object *args, ptrdiff_t nargs) { + ptrdiff_t count = SPECPDL_INDEX (); + eassert (nargs >= UNEVALLED); specpdl_ptr->bt.kind = SPECPDL_BACKTRACE; specpdl_ptr->bt.debug_on_exit = false; @@ -2044,6 +2041,8 @@ record_in_backtrace (Lisp_Object function, Lisp_Object *args, ptrdiff_t nargs) specpdl_ptr->bt.args = args; specpdl_ptr->bt.nargs = nargs; grow_specpdl (); + + return count; } /* Eval a sub-expression of the current expression (i.e. in the same @@ -2054,6 +2053,7 @@ eval_sub (Lisp_Object form) Lisp_Object fun, val, original_fun, original_args; Lisp_Object funcar; struct gcpro gcpro1, gcpro2, gcpro3; + ptrdiff_t count; if (SYMBOLP (form)) { @@ -2091,10 +2091,10 @@ eval_sub (Lisp_Object form) original_args = XCDR (form); /* This also protects them from gc. */ - record_in_backtrace (original_fun, &original_args, UNEVALLED); + count = record_in_backtrace (original_fun, &original_args, UNEVALLED); if (debug_on_next_call) - do_debug_on_call (Qt); + do_debug_on_call (Qt, count); /* At this point, only original_fun and original_args have values that will be used below. */ @@ -2102,8 +2102,9 @@ eval_sub (Lisp_Object form) /* Optimize for no indirection. */ fun = original_fun; - if (SYMBOLP (fun) && !NILP (fun) - && (fun = XSYMBOL (fun)->function, SYMBOLP (fun))) + if (!SYMBOLP (fun)) + fun = Ffunction (Fcons (fun, Qnil)); + else if (!NILP (fun) && (fun = XSYMBOL (fun)->function, SYMBOLP (fun))) fun = indirect_function (fun); if (SUBRP (fun)) @@ -2145,8 +2146,7 @@ eval_sub (Lisp_Object form) gcpro3.nvars = argnum; } - set_backtrace_args (specpdl_ptr - 1, vals); - set_backtrace_nargs (specpdl_ptr - 1, XINT (numargs)); + set_backtrace_args (specpdl + count, vals, XINT (numargs)); val = (XSUBR (fun)->function.aMANY) (XINT (numargs), vals); UNGCPRO; @@ -2167,8 +2167,7 @@ eval_sub (Lisp_Object form) UNGCPRO; - set_backtrace_args (specpdl_ptr - 1, argvals); - set_backtrace_nargs (specpdl_ptr - 1, XINT (numargs)); + set_backtrace_args (specpdl + count, argvals, XINT (numargs)); switch (i) { @@ -2221,7 +2220,7 @@ eval_sub (Lisp_Object form) } } else if (COMPILEDP (fun)) - val = apply_lambda (fun, original_args); + val = apply_lambda (fun, original_args, count); else { if (NILP (fun)) @@ -2238,7 +2237,7 @@ eval_sub (Lisp_Object form) } if (EQ (funcar, Qmacro)) { - ptrdiff_t count = SPECPDL_INDEX (); + ptrdiff_t count1 = SPECPDL_INDEX (); Lisp_Object exp; /* Bind lexical-binding during expansion of the macro, so the macro can know reliably if the code it outputs will be @@ -2246,19 +2245,19 @@ eval_sub (Lisp_Object form) specbind (Qlexical_binding, NILP (Vinternal_interpreter_environment) ? Qnil : Qt); exp = apply1 (Fcdr (fun), original_args); - unbind_to (count, Qnil); + unbind_to (count1, Qnil); val = eval_sub (exp); } else if (EQ (funcar, Qlambda) || EQ (funcar, Qclosure)) - val = apply_lambda (fun, original_args); + val = apply_lambda (fun, original_args, count); else xsignal1 (Qinvalid_function, original_fun); } check_cons_list (); lisp_eval_depth--; - if (backtrace_debug_on_exit (specpdl_ptr - 1)) + if (backtrace_debug_on_exit (specpdl + count)) val = call_debugger (list2 (Qexit, val)); specpdl_ptr--; @@ -2272,12 +2271,10 @@ Thus, (apply '+ 1 2 '(3 4)) returns 10. usage: (apply FUNCTION &rest ARGUMENTS) */) (ptrdiff_t nargs, Lisp_Object *args) { - ptrdiff_t i; - EMACS_INT numargs; + ptrdiff_t i, numargs, funcall_nargs; register Lisp_Object spread_arg; register Lisp_Object *funcall_args; Lisp_Object fun, retval; - struct gcpro gcpro1; USE_SAFE_ALLOCA; fun = args [0]; @@ -2318,10 +2315,9 @@ usage: (apply FUNCTION &rest ARGUMENTS) */) /* Avoid making funcall cons up a yet another new vector of arguments by explicitly supplying nil's for optional values. */ SAFE_ALLOCA_LISP (funcall_args, 1 + XSUBR (fun)->max_args); - for (i = numargs; i < XSUBR (fun)->max_args;) + for (i = numargs; i < XSUBR (fun)->max_args; /* nothing */) funcall_args[++i] = Qnil; - GCPRO1 (*funcall_args); - gcpro1.nvars = 1 + XSUBR (fun)->max_args; + funcall_nargs = 1 + XSUBR (fun)->max_args; } } funcall: @@ -2330,8 +2326,7 @@ usage: (apply FUNCTION &rest ARGUMENTS) */) if (!funcall_args) { SAFE_ALLOCA_LISP (funcall_args, 1 + numargs); - GCPRO1 (*funcall_args); - gcpro1.nvars = 1 + numargs; + funcall_nargs = 1 + numargs; } memcpy (funcall_args, args, nargs * word_size); @@ -2344,11 +2339,10 @@ usage: (apply FUNCTION &rest ARGUMENTS) */) spread_arg = XCDR (spread_arg); } - /* By convention, the caller needs to gcpro Ffuncall's args. */ - retval = Ffuncall (gcpro1.nvars, funcall_args); - UNGCPRO; - SAFE_FREE (); + /* Ffuncall gcpro's all of its args. */ + retval = Ffuncall (funcall_nargs, funcall_args); + SAFE_FREE (); return retval; } @@ -2499,7 +2493,7 @@ run_hook_with_args (ptrdiff_t nargs, Lisp_Object *args, if (EQ (val, Qunbound) || NILP (val)) return ret; - else if (!CONSP (val) || EQ (XCAR (val), Qlambda)) + else if (!CONSP (val) || FUNCTIONP (val)) { args[0] = val; return funcall (nargs, args); @@ -2556,41 +2550,22 @@ run_hook_with_args (ptrdiff_t nargs, Lisp_Object *args, void run_hook_with_args_2 (Lisp_Object hook, Lisp_Object arg1, Lisp_Object arg2) { - Lisp_Object temp[3]; - temp[0] = hook; - temp[1] = arg1; - temp[2] = arg2; - - Frun_hook_with_args (3, temp); + Frun_hook_with_args (3, ((Lisp_Object []) { hook, arg1, arg2 })); } - + /* Apply fn to arg. */ Lisp_Object apply1 (Lisp_Object fn, Lisp_Object arg) { - struct gcpro gcpro1; - - GCPRO1 (fn); - if (NILP (arg)) - RETURN_UNGCPRO (Ffuncall (1, &fn)); - gcpro1.nvars = 2; - { - Lisp_Object args[2]; - args[0] = fn; - args[1] = arg; - gcpro1.var = args; - RETURN_UNGCPRO (Fapply (2, args)); - } + return (NILP (arg) ? Ffuncall (1, &fn) + : Fapply (2, ((Lisp_Object []) { fn, arg }))); } /* Call function fn on no arguments. */ Lisp_Object call0 (Lisp_Object fn) { - struct gcpro gcpro1; - - GCPRO1 (fn); - RETURN_UNGCPRO (Ffuncall (1, &fn)); + return Ffuncall (1, &fn); } /* Call function fn with 1 argument arg1. */ @@ -2598,14 +2573,7 @@ call0 (Lisp_Object fn) Lisp_Object call1 (Lisp_Object fn, Lisp_Object arg1) { - struct gcpro gcpro1; - Lisp_Object args[2]; - - args[0] = fn; - args[1] = arg1; - GCPRO1 (args[0]); - gcpro1.nvars = 2; - RETURN_UNGCPRO (Ffuncall (2, args)); + return Ffuncall (2, ((Lisp_Object []) { fn, arg1 })); } /* Call function fn with 2 arguments arg1, arg2. */ @@ -2613,14 +2581,7 @@ call1 (Lisp_Object fn, Lisp_Object arg1) Lisp_Object call2 (Lisp_Object fn, Lisp_Object arg1, Lisp_Object arg2) { - struct gcpro gcpro1; - Lisp_Object args[3]; - args[0] = fn; - args[1] = arg1; - args[2] = arg2; - GCPRO1 (args[0]); - gcpro1.nvars = 3; - RETURN_UNGCPRO (Ffuncall (3, args)); + return Ffuncall (3, ((Lisp_Object []) { fn, arg1, arg2 })); } /* Call function fn with 3 arguments arg1, arg2, arg3. */ @@ -2628,15 +2589,7 @@ call2 (Lisp_Object fn, Lisp_Object arg1, Lisp_Object arg2) Lisp_Object call3 (Lisp_Object fn, Lisp_Object arg1, Lisp_Object arg2, Lisp_Object arg3) { - struct gcpro gcpro1; - Lisp_Object args[4]; - args[0] = fn; - args[1] = arg1; - args[2] = arg2; - args[3] = arg3; - GCPRO1 (args[0]); - gcpro1.nvars = 4; - RETURN_UNGCPRO (Ffuncall (4, args)); + return Ffuncall (4, ((Lisp_Object []) { fn, arg1, arg2, arg3 })); } /* Call function fn with 4 arguments arg1, arg2, arg3, arg4. */ @@ -2645,16 +2598,7 @@ Lisp_Object call4 (Lisp_Object fn, Lisp_Object arg1, Lisp_Object arg2, Lisp_Object arg3, Lisp_Object arg4) { - struct gcpro gcpro1; - Lisp_Object args[5]; - args[0] = fn; - args[1] = arg1; - args[2] = arg2; - args[3] = arg3; - args[4] = arg4; - GCPRO1 (args[0]); - gcpro1.nvars = 5; - RETURN_UNGCPRO (Ffuncall (5, args)); + return Ffuncall (5, ((Lisp_Object []) { fn, arg1, arg2, arg3, arg4 })); } /* Call function fn with 5 arguments arg1, arg2, arg3, arg4, arg5. */ @@ -2663,17 +2607,7 @@ Lisp_Object call5 (Lisp_Object fn, Lisp_Object arg1, Lisp_Object arg2, Lisp_Object arg3, Lisp_Object arg4, Lisp_Object arg5) { - struct gcpro gcpro1; - Lisp_Object args[6]; - args[0] = fn; - args[1] = arg1; - args[2] = arg2; - args[3] = arg3; - args[4] = arg4; - args[5] = arg5; - GCPRO1 (args[0]); - gcpro1.nvars = 6; - RETURN_UNGCPRO (Ffuncall (6, args)); + return Ffuncall (6, ((Lisp_Object []) { fn, arg1, arg2, arg3, arg4, arg5 })); } /* Call function fn with 6 arguments arg1, arg2, arg3, arg4, arg5, arg6. */ @@ -2682,18 +2616,8 @@ Lisp_Object call6 (Lisp_Object fn, Lisp_Object arg1, Lisp_Object arg2, Lisp_Object arg3, Lisp_Object arg4, Lisp_Object arg5, Lisp_Object arg6) { - struct gcpro gcpro1; - Lisp_Object args[7]; - args[0] = fn; - args[1] = arg1; - args[2] = arg2; - args[3] = arg3; - args[4] = arg4; - args[5] = arg5; - args[6] = arg6; - GCPRO1 (args[0]); - gcpro1.nvars = 7; - RETURN_UNGCPRO (Ffuncall (7, args)); + return Ffuncall (7, ((Lisp_Object []) + { fn, arg1, arg2, arg3, arg4, arg5, arg6 })); } /* Call function fn with 7 arguments arg1, arg2, arg3, arg4, arg5, arg6, arg7. */ @@ -2702,19 +2626,8 @@ Lisp_Object call7 (Lisp_Object fn, Lisp_Object arg1, Lisp_Object arg2, Lisp_Object arg3, Lisp_Object arg4, Lisp_Object arg5, Lisp_Object arg6, Lisp_Object arg7) { - struct gcpro gcpro1; - Lisp_Object args[8]; - args[0] = fn; - args[1] = arg1; - args[2] = arg2; - args[3] = arg3; - args[4] = arg4; - args[5] = arg5; - args[6] = arg6; - args[7] = arg7; - GCPRO1 (args[0]); - gcpro1.nvars = 8; - RETURN_UNGCPRO (Ffuncall (8, args)); + return Ffuncall (8, ((Lisp_Object []) + { fn, arg1, arg2, arg3, arg4, arg5, arg6, arg7 })); } /* The caller should GCPRO all the elements of ARGS. */ @@ -2741,7 +2654,7 @@ usage: (funcall FUNCTION &rest ARGUMENTS) */) Lisp_Object lisp_numargs; Lisp_Object val; register Lisp_Object *internal_args; - ptrdiff_t i; + ptrdiff_t i, count; QUIT; @@ -2754,13 +2667,13 @@ usage: (funcall FUNCTION &rest ARGUMENTS) */) } /* This also GCPROs them. */ - record_in_backtrace (args[0], &args[1], nargs - 1); + count = record_in_backtrace (args[0], &args[1], nargs - 1); /* Call GC after setting up the backtrace, so the latter GCPROs the args. */ maybe_gc (); if (debug_on_next_call) - do_debug_on_call (Qlambda); + do_debug_on_call (Qlambda, count); check_cons_list (); @@ -2790,10 +2703,11 @@ usage: (funcall FUNCTION &rest ARGUMENTS) */) val = (XSUBR (fun)->function.aMANY) (numargs, args + 1); else { + Lisp_Object internal_argbuf[8]; if (XSUBR (fun)->max_args > numargs) { - internal_args = alloca (XSUBR (fun)->max_args - * sizeof *internal_args); + eassert (XSUBR (fun)->max_args <= ARRAYELTS (internal_argbuf)); + internal_args = internal_argbuf; memcpy (internal_args, args + 1, numargs * word_size); for (i = numargs; i < XSUBR (fun)->max_args; i++) internal_args[i] = Qnil; @@ -2879,14 +2793,14 @@ usage: (funcall FUNCTION &rest ARGUMENTS) */) } check_cons_list (); lisp_eval_depth--; - if (backtrace_debug_on_exit (specpdl_ptr - 1)) + if (backtrace_debug_on_exit (specpdl + count)) val = call_debugger (list2 (Qexit, val)); specpdl_ptr--; return val; } static Lisp_Object -apply_lambda (Lisp_Object fun, Lisp_Object args) +apply_lambda (Lisp_Object fun, Lisp_Object args, ptrdiff_t count) { Lisp_Object args_left; ptrdiff_t i; @@ -2913,15 +2827,14 @@ apply_lambda (Lisp_Object fun, Lisp_Object args) UNGCPRO; - set_backtrace_args (specpdl_ptr - 1, arg_vector); - set_backtrace_nargs (specpdl_ptr - 1, i); + set_backtrace_args (specpdl + count, arg_vector, i); tem = funcall_lambda (fun, numargs, arg_vector); /* Do the debug-on-exit now, while arg_vector still exists. */ - if (backtrace_debug_on_exit (specpdl_ptr - 1)) + if (backtrace_debug_on_exit (specpdl + count)) { /* Don't do it again when we return to eval. */ - set_backtrace_debug_on_exit (specpdl_ptr - 1, false); + set_backtrace_debug_on_exit (specpdl + count, false); tem = call_debugger (list2 (Qexit, tem)); } SAFE_FREE (); @@ -3107,20 +3020,17 @@ let_shadows_global_binding_p (Lisp_Object symbol) return 0; } -/* `specpdl_ptr->symbol' is a field which describes which variable is +/* `specpdl_ptr' describes which variable is let-bound, so it can be properly undone when we unbind_to. - It can have the following two shapes: - - SYMBOL : if it's a plain symbol, it means that we have let-bound - a symbol that is not buffer-local (at least at the time - the let binding started). Note also that it should not be + It can be either a plain SPECPDL_LET or a SPECPDL_LET_LOCAL/DEFAULT. + - SYMBOL is the variable being bound. Note that it should not be aliased (i.e. when let-binding V1 that's aliased to V2, we want to record V2 here). - - (SYMBOL WHERE . BUFFER) : this means that it is a let-binding for - variable SYMBOL which can be buffer-local. WHERE tells us - which buffer is affected (or nil if the let-binding affects the - global value of the variable) and BUFFER tells us which buffer was - current (i.e. if WHERE is non-nil, then BUFFER==WHERE, otherwise - BUFFER did not yet have a buffer-local value). */ + - WHERE tells us in which buffer the binding took place. + This is used for SPECPDL_LET_LOCAL bindings (i.e. bindings to a + buffer-local variable) as well as for SPECPDL_LET_DEFAULT bindings, + i.e. bindings to the default value of a variable which can be + buffer-local. */ void specbind (Lisp_Object symbol, Lisp_Object value) @@ -3257,6 +3167,16 @@ clear_unwind_protect (ptrdiff_t count) It need not be at the top of the stack. Discard the entry's previous value without invoking it. */ +void +set_unwind_protect (ptrdiff_t count, void (*func) (Lisp_Object), + Lisp_Object arg) +{ + union specbinding *p = specpdl + count; + p->unwind.kind = SPECPDL_UNWIND; + p->unwind.func = func; + p->unwind.arg = arg; +} + void set_unwind_protect_ptr (ptrdiff_t count, void (*func) (void *), void *arg) { @@ -3301,41 +3221,38 @@ unbind_to (ptrdiff_t count, Lisp_Object value) case SPECPDL_UNWIND_VOID: specpdl_ptr->unwind_void.func (); break; - case SPECPDL_LET: - /* If variable has a trivial value (no forwarding), we can - just set it. No need to check for constant symbols here, - since that was already done by specbind. */ - if (XSYMBOL (specpdl_symbol (specpdl_ptr))->redirect - == SYMBOL_PLAINVAL) - SET_SYMBOL_VAL (XSYMBOL (specpdl_symbol (specpdl_ptr)), - specpdl_old_value (specpdl_ptr)); - else - /* NOTE: we only ever come here if make_local_foo was used for - the first time on this var within this let. */ - Fset_default (specpdl_symbol (specpdl_ptr), - specpdl_old_value (specpdl_ptr)); - break; case SPECPDL_BACKTRACE: break; - case SPECPDL_LET_LOCAL: + case SPECPDL_LET: + { /* If variable has a trivial value (no forwarding), we can + just set it. No need to check for constant symbols here, + since that was already done by specbind. */ + struct Lisp_Symbol *sym = XSYMBOL (specpdl_symbol (specpdl_ptr)); + if (sym->redirect == SYMBOL_PLAINVAL) + { + SET_SYMBOL_VAL (sym, specpdl_old_value (specpdl_ptr)); + break; + } + else + { /* FALLTHROUGH!! + NOTE: we only ever come here if make_local_foo was used for + the first time on this var within this let. */ + } + } case SPECPDL_LET_DEFAULT: - { /* If the symbol is a list, it is really (SYMBOL WHERE - . CURRENT-BUFFER) where WHERE is either nil, a buffer, or a - frame. If WHERE is a buffer or frame, this indicates we - bound a variable that had a buffer-local or frame-local - binding. WHERE nil means that the variable had the default - value when it was bound. CURRENT-BUFFER is the buffer that - was current when the variable was bound. */ + Fset_default (specpdl_symbol (specpdl_ptr), + specpdl_old_value (specpdl_ptr)); + break; + case SPECPDL_LET_LOCAL: + { Lisp_Object symbol = specpdl_symbol (specpdl_ptr); Lisp_Object where = specpdl_where (specpdl_ptr); Lisp_Object old_value = specpdl_old_value (specpdl_ptr); eassert (BUFFERP (where)); - if (specpdl_ptr->kind == SPECPDL_LET_DEFAULT) - Fset_default (symbol, old_value); /* If this was a local binding, reset the value in the appropriate buffer, but only if that buffer's binding still exists. */ - else if (!NILP (Flocal_variable_p (symbol, where))) + if (!NILP (Flocal_variable_p (symbol, where))) set_internal (symbol, old_value, where, 1); } break; @@ -3422,7 +3339,30 @@ Output stream used is value of `standard-output'. */) return Qnil; } -DEFUN ("backtrace-frame", Fbacktrace_frame, Sbacktrace_frame, 1, 1, NULL, +static union specbinding * +get_backtrace_frame (Lisp_Object nframes, Lisp_Object base) +{ + union specbinding *pdl = backtrace_top (); + register EMACS_INT i; + + CHECK_NATNUM (nframes); + + if (!NILP (base)) + { /* Skip up to `base'. */ + base = Findirect_function (base, Qt); + while (backtrace_p (pdl) + && !EQ (base, Findirect_function (backtrace_function (pdl), Qt))) + pdl = backtrace_next (pdl); + } + + /* Find the frame requested. */ + for (i = XFASTINT (nframes); i > 0 && backtrace_p (pdl); i--) + pdl = backtrace_next (pdl); + + return pdl; +} + +DEFUN ("backtrace-frame", Fbacktrace_frame, Sbacktrace_frame, 1, 2, NULL, doc: /* Return the function and arguments NFRAMES up from current execution point. If that frame has not evaluated the arguments yet (or is a special form), the value is (nil FUNCTION ARG-FORMS...). @@ -3431,17 +3371,12 @@ the value is (t FUNCTION ARG-VALUES...). A &rest arg is represented as the tail of the list ARG-VALUES. FUNCTION is whatever was supplied as car of evaluated list, or a lambda expression for macro calls. -If NFRAMES is more than the number of frames, the value is nil. */) - (Lisp_Object nframes) +If NFRAMES is more than the number of frames, the value is nil. +If BASE is non-nil, it should be a function and NFRAMES counts from its +nearest activation frame. */) + (Lisp_Object nframes, Lisp_Object base) { - union specbinding *pdl = backtrace_top (); - register EMACS_INT i; - - CHECK_NATNUM (nframes); - - /* Find the frame requested. */ - for (i = 0; backtrace_p (pdl) && i < XFASTINT (nframes); i++) - pdl = backtrace_next (pdl); + union specbinding *pdl = get_backtrace_frame (nframes, base); if (!backtrace_p (pdl)) return Qnil; @@ -3456,6 +3391,175 @@ If NFRAMES is more than the number of frames, the value is nil. */) } } +/* For backtrace-eval, we want to temporarily unwind the last few elements of + the specpdl stack, and then rewind them. We store the pre-unwind values + directly in the pre-existing specpdl elements (i.e. we swap the current + value and the old value stored in the specpdl), kind of like the inplace + pointer-reversal trick. As it turns out, the rewind does the same as the + unwind, except it starts from the other end of the specpdl stack, so we use + the same function for both unwind and rewind. */ +static void +backtrace_eval_unrewind (int distance) +{ + union specbinding *tmp = specpdl_ptr; + int step = -1; + if (distance < 0) + { /* It's a rewind rather than unwind. */ + tmp += distance - 1; + step = 1; + distance = -distance; + } + + for (; distance > 0; distance--) + { + tmp += step; + /* */ + switch (tmp->kind) + { + /* FIXME: Ideally we'd like to "temporarily unwind" (some of) those + unwind_protect, but the problem is that we don't know how to + rewind them afterwards. */ + case SPECPDL_UNWIND: + case SPECPDL_UNWIND_PTR: + case SPECPDL_UNWIND_INT: + case SPECPDL_UNWIND_VOID: + case SPECPDL_BACKTRACE: + break; + case SPECPDL_LET: + { /* If variable has a trivial value (no forwarding), we can + just set it. No need to check for constant symbols here, + since that was already done by specbind. */ + struct Lisp_Symbol *sym = XSYMBOL (specpdl_symbol (tmp)); + if (sym->redirect == SYMBOL_PLAINVAL) + { + Lisp_Object old_value = specpdl_old_value (tmp); + set_specpdl_old_value (tmp, SYMBOL_VAL (sym)); + SET_SYMBOL_VAL (sym, old_value); + break; + } + else + { /* FALLTHROUGH!! + NOTE: we only ever come here if make_local_foo was used for + the first time on this var within this let. */ + } + } + case SPECPDL_LET_DEFAULT: + { + Lisp_Object sym = specpdl_symbol (tmp); + Lisp_Object old_value = specpdl_old_value (tmp); + set_specpdl_old_value (tmp, Fdefault_value (sym)); + Fset_default (sym, old_value); + } + break; + case SPECPDL_LET_LOCAL: + { + Lisp_Object symbol = specpdl_symbol (tmp); + Lisp_Object where = specpdl_where (tmp); + Lisp_Object old_value = specpdl_old_value (tmp); + eassert (BUFFERP (where)); + + /* If this was a local binding, reset the value in the appropriate + buffer, but only if that buffer's binding still exists. */ + if (!NILP (Flocal_variable_p (symbol, where))) + { + set_specpdl_old_value + (tmp, Fbuffer_local_value (symbol, where)); + set_internal (symbol, old_value, where, 1); + } + } + break; + } + } +} + +DEFUN ("backtrace-eval", Fbacktrace_eval, Sbacktrace_eval, 2, 3, NULL, + doc: /* Evaluate EXP in the context of some activation frame. +NFRAMES and BASE specify the activation frame to use, as in `backtrace-frame'. */) + (Lisp_Object exp, Lisp_Object nframes, Lisp_Object base) +{ + union specbinding *pdl = get_backtrace_frame (nframes, base); + ptrdiff_t count = SPECPDL_INDEX (); + ptrdiff_t distance = specpdl_ptr - pdl; + eassert (distance >= 0); + + if (!backtrace_p (pdl)) + error ("Activation frame not found!"); + + backtrace_eval_unrewind (distance); + record_unwind_protect_int (backtrace_eval_unrewind, -distance); + + /* Use eval_sub rather than Feval since the main motivation behind + backtrace-eval is to be able to get/set the value of lexical variables + from the debugger. */ + return unbind_to (count, eval_sub (exp)); +} + +DEFUN ("backtrace--locals", Fbacktrace__locals, Sbacktrace__locals, 1, 2, NULL, + doc: /* Return names and values of local variables of a stack frame. +NFRAMES and BASE specify the activation frame to use, as in `backtrace-frame'. */) + (Lisp_Object nframes, Lisp_Object base) +{ + union specbinding *frame = get_backtrace_frame (nframes, base); + union specbinding *prevframe + = get_backtrace_frame (make_number (XFASTINT (nframes) - 1), base); + ptrdiff_t distance = specpdl_ptr - frame; + Lisp_Object result = Qnil; + eassert (distance >= 0); + + if (!backtrace_p (prevframe)) + error ("Activation frame not found!"); + if (!backtrace_p (frame)) + error ("Activation frame not found!"); + + /* The specpdl entries normally contain the symbol being bound along with its + `old_value', so it can be restored. The new value to which it is bound is + available in one of two places: either in the current value of the + variable (if it hasn't been rebound yet) or in the `old_value' slot of the + next specpdl entry for it. + `backtrace_eval_unrewind' happens to swap the role of `old_value' + and "new value", so we abuse it here, to fetch the new value. + It's ugly (we'd rather not modify global data) and a bit inefficient, + but it does the job for now. */ + backtrace_eval_unrewind (distance); + + /* Grab values. */ + { + union specbinding *tmp = prevframe; + for (; tmp > frame; tmp--) + { + switch (tmp->kind) + { + case SPECPDL_LET: + case SPECPDL_LET_DEFAULT: + case SPECPDL_LET_LOCAL: + { + Lisp_Object sym = specpdl_symbol (tmp); + Lisp_Object val = specpdl_old_value (tmp); + if (EQ (sym, Qinternal_interpreter_environment)) + { + Lisp_Object env = val; + for (; CONSP (env); env = XCDR (env)) + { + Lisp_Object binding = XCAR (env); + if (CONSP (binding)) + result = Fcons (Fcons (XCAR (binding), + XCDR (binding)), + result); + } + } + else + result = Fcons (Fcons (sym, val), result); + } + } + } + } + + /* Restore values from specpdl to original place. */ + backtrace_eval_unrewind (-distance); + + return result; +} + void mark_specpdl (void) @@ -3526,7 +3630,9 @@ If Lisp code tries to increase the total number past this amount, an error is signaled. You can safely use a value considerably larger than the default value, if that proves inconveniently small. However, if you increase it too far, -Emacs could run out of memory trying to make the stack bigger. */); +Emacs could run out of memory trying to make the stack bigger. +Note that this limit may be silently increased by the debugger +if `debug-on-error' or `debug-on-quit' is set. */); DEFVAR_INT ("max-lisp-eval-depth", max_lisp_eval_depth, doc: /* Limit on depth in `eval', `apply' and `funcall' before error. @@ -3673,6 +3779,8 @@ alist of active lexical bindings. */); defsubr (&Ssetq); defsubr (&Squote); defsubr (&Sfunction); + defsubr (&Sdefault_toplevel_value); + defsubr (&Sset_default_toplevel_value); defsubr (&Sdefvar); defsubr (&Sdefvaralias); defsubr (&Sdefconst); @@ -3701,6 +3809,8 @@ alist of active lexical bindings. */); defsubr (&Sbacktrace_debug); defsubr (&Sbacktrace); defsubr (&Sbacktrace_frame); + defsubr (&Sbacktrace_eval); + defsubr (&Sbacktrace__locals); defsubr (&Sspecial_variable_p); defsubr (&Sfunctionp); }