From b52f569dcfc5c2e1b764c89d27ea8699a44228e6 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Wed, 2 Oct 2013 23:31:06 -0700 Subject: [PATCH] * eval.c (clobbered_eassert): New macro. (internal_catch, internal_condition_case) (internal_condition_case_1, internal_condition_case_2) (internal_condition_case_n): Use it instead of eassert when the argument contains locals clobbered by longjmp. Don't use clobbered locals outside of clobbered_eassert. (internal_lisp_condition_case): Use a volatile variable to work around a local variable's getting clobbered. --- src/ChangeLog | 11 +++++++++++ src/eval.c | 39 +++++++++++++++++++++++---------------- 2 files changed, 34 insertions(+), 16 deletions(-) diff --git a/src/ChangeLog b/src/ChangeLog index 4b1bfc75187..8a0d8863548 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,3 +1,14 @@ +2013-10-03 Paul Eggert + + * eval.c (clobbered_eassert): New macro. + (internal_catch, internal_condition_case) + (internal_condition_case_1, internal_condition_case_2) + (internal_condition_case_n): Use it instead of eassert + when the argument contains locals clobbered by longjmp. + Don't use clobbered locals outside of clobbered_eassert. + (internal_lisp_condition_case): Use a volatile variable + to work around a local variable's getting clobbered. + 2013-10-03 Stefan Monnier * lisp.h (struct handler): Merge struct handler and struct catchtag. diff --git a/src/eval.c b/src/eval.c index 5526b28b2e0..3b4dc9a88d1 100644 --- a/src/eval.c +++ b/src/eval.c @@ -1072,6 +1072,12 @@ 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. */ @@ -1089,14 +1095,14 @@ internal_catch (Lisp_Object tag, Lisp_Object (*func) (Lisp_Object), Lisp_Object if (! sys_setjmp (c->jmp)) { Lisp_Object val = (*func) (arg); - eassert (handlerlist == c); - handlerlist = c->next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } else { /* Throw works by a longjmp that comes right here. */ Lisp_Object val = handlerlist->val; - eassert (handlerlist == c); + clobbered_eassert (handlerlist == c); handlerlist = handlerlist->next; return val; } @@ -1252,6 +1258,7 @@ internal_lisp_condition_case (volatile Lisp_Object var, Lisp_Object bodyform, be added to handlerlist last. So we build in `clauses' a table that contains `handlers' but in reverse order. */ Lisp_Object *clauses = alloca (clausenb * sizeof (Lisp_Object *)); + Lisp_Object *volatile clauses_volatile = clauses; int i = clausenb; for (val = handlers; CONSP (val); val = XCDR (val)) clauses[--i] = XCAR (val); @@ -1266,7 +1273,7 @@ internal_lisp_condition_case (volatile Lisp_Object var, Lisp_Object bodyform, { ptrdiff_t count = SPECPDL_INDEX (); Lisp_Object val = handlerlist->val; - Lisp_Object *chosen_clause = clauses; + Lisp_Object *chosen_clause = clauses_volatile; for (c = handlerlist->next; c != oldhandlerlist; c = c->next) chosen_clause++; handlerlist = oldhandlerlist; @@ -1316,14 +1323,14 @@ internal_condition_case (Lisp_Object (*bfun) (void), Lisp_Object handlers, if (sys_setjmp (c->jmp)) { Lisp_Object val = handlerlist->val; - eassert (handlerlist == c); + clobbered_eassert (handlerlist == c); handlerlist = handlerlist->next; return (*hfun) (val); } val = (*bfun) (); - eassert (handlerlist == c); - handlerlist = c->next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } @@ -1340,14 +1347,14 @@ internal_condition_case_1 (Lisp_Object (*bfun) (Lisp_Object), Lisp_Object arg, if (sys_setjmp (c->jmp)) { Lisp_Object val = handlerlist->val; - eassert (handlerlist == c); + clobbered_eassert (handlerlist == c); handlerlist = handlerlist->next; return (*hfun) (val); } val = (*bfun) (arg); - eassert (handlerlist == c); - handlerlist = c->next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } @@ -1368,14 +1375,14 @@ internal_condition_case_2 (Lisp_Object (*bfun) (Lisp_Object, Lisp_Object), if (sys_setjmp (c->jmp)) { Lisp_Object val = handlerlist->val; - eassert (handlerlist == c); + clobbered_eassert (handlerlist == c); handlerlist = handlerlist->next; return (*hfun) (val); } val = (*bfun) (arg1, arg2); - eassert (handlerlist == c); - handlerlist = c->next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } @@ -1398,14 +1405,14 @@ internal_condition_case_n (Lisp_Object (*bfun) (ptrdiff_t, Lisp_Object *), if (sys_setjmp (c->jmp)) { Lisp_Object val = handlerlist->val; - eassert (handlerlist == c); + clobbered_eassert (handlerlist == c); handlerlist = handlerlist->next; return (*hfun) (val, nargs, args); } val = (*bfun) (nargs, args); - eassert (handlerlist == c); - handlerlist = c->next; + clobbered_eassert (handlerlist == c); + handlerlist = handlerlist->next; return val; } -- 2.39.2