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* eval.c (clobbered_eassert): New macro.

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(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.
This commit is contained in:
Paul Eggert 2013-10-02 23:31:06 -07:00
parent adf2aa6140
commit b52f569dcf
2 changed files with 34 additions and 16 deletions
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11
src/ChangeLog
View file

@ -1,3 +1,14 @@
2013-10-03 Paul Eggert <eggert@cs.ucla.edu>
* 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 <monnier@iro.umontreal.ca>
* lisp.h (struct handler): Merge struct handler and struct catchtag.

39
src/eval.c
View file

@ -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;
}