Change 27742 by [EMAIL PROTECTED] on 2006/04/08 17:28:28
Integrate:
[ 27615]
If constant folding fails, don't fold constants, rather than reporting
the error at compile time. This allows illegal constant expressions in
dead code to be ignored.
[ 27616]
It helps to actually add the files you add to MANIFEST. (Thanks Dave
for spotting my mistake).
Affected files ...
... //depot/maint-5.8/perl/MANIFEST#280 integrate
... //depot/maint-5.8/perl/op.c#125 integrate
... //depot/maint-5.8/perl/pod/perldiag.pod#85 integrate
... //depot/maint-5.8/perl/pod/perltodo.pod#22 integrate
... //depot/maint-5.8/perl/t/comp/fold.t#1 branch
Differences ...
==== //depot/maint-5.8/perl/MANIFEST#280 (text) ====
Index: perl/MANIFEST
--- perl/MANIFEST#279~27604~ 2006-03-25 07:15:28.000000000 -0800
+++ perl/MANIFEST 2006-04-08 10:28:28.000000000 -0700
@@ -2540,6 +2540,7 @@
t/comp/cpp.aux main file for cpp.t
t/comp/cpp.t See if C preprocessor works
t/comp/decl.t See if declarations work
+t/comp/fold.t See if constant folding works
t/comp/hints.t See if %^H works
t/comp/multiline.t See if multiline strings work
t/comp/opsubs.t See if q() etc. are not parsed as
functions
==== //depot/maint-5.8/perl/op.c#125 (text) ====
Index: perl/op.c
--- perl/op.c#124~27310~ 2006-02-24 05:20:45.000000000 -0800
+++ perl/op.c 2006-04-08 10:28:28.000000000 -0700
@@ -2065,6 +2065,10 @@
register OP *curop;
I32 type = o->op_type;
SV *sv;
+ int ret = 0;
+ I32 oldscope;
+ OP *old_next;
+ dJMPENV;
if (PL_opargs[type] & OA_RETSCALAR)
scalar(o);
@@ -2118,22 +2122,78 @@
}
curop = LINKLIST(o);
+ old_next = o->op_next;
o->op_next = 0;
PL_op = curop;
- CALLRUNOPS(aTHX);
- sv = *(PL_stack_sp--);
- if (o->op_targ && sv == PAD_SV(o->op_targ)) /* grab pad temp? */
- pad_swipe(o->op_targ, FALSE);
- else if (SvTEMP(sv)) { /* grab mortal temp? */
- (void)SvREFCNT_inc(sv);
- SvTEMP_off(sv);
+
+ oldscope = PL_scopestack_ix;
+
+ /* we're trying to emulate pp_entertry() here */
+ {
+ register PERL_CONTEXT *cx;
+ const I32 gimme = GIMME_V;
+
+ ENTER;
+ SAVETMPS;
+
+ PUSHBLOCK(cx, (CXt_EVAL|CXp_TRYBLOCK), PL_stack_sp);
+ PUSHEVAL(cx, 0, 0);
+ PL_eval_root = PL_op; /* Only needed so that goto works
right. */
+
+ PL_in_eval = EVAL_INEVAL;
+ sv_setpvn(ERRSV,"",0);
+ }
+ JMPENV_PUSH(ret);
+
+ switch (ret) {
+ case 0:
+ CALLRUNOPS(aTHX);
+ sv = *(PL_stack_sp--);
+ if (o->op_targ && sv == PAD_SV(o->op_targ)) /* grab pad temp? */
+ pad_swipe(o->op_targ, FALSE);
+ else if (SvTEMP(sv)) { /* grab mortal temp? */
+ SvREFCNT_inc(sv);
+ SvTEMP_off(sv);
+ }
+ break;
+ case 3:
+ /* Something tried to die. Abandon constant folding. */
+ /* Pretend the error never happened. */
+ sv_setpvn(ERRSV,"",0);
+ o->op_next = old_next;
+ break;
+ default:
+ JMPENV_POP;
+ /* Don't expect 1 (setjmp failed) or 2 (something called my_exit) */
+ Perl_croak(aTHX_ "panic: fold_constants JMPENV_PUSH returned %d", ret);
+ }
+
+ JMPENV_POP;
+ if (PL_scopestack_ix > oldscope) {
+ SV **newsp;
+ PMOP *newpm;
+ I32 gimme;
+ register PERL_CONTEXT *cx;
+ I32 optype;
+
+ POPBLOCK(cx,newpm);
+ POPEVAL(cx);
+ PL_curpm = newpm;
+ LEAVE;
+ PERL_UNUSED_VAR(newsp);
+ PERL_UNUSED_VAR(gimme);
+ PERL_UNUSED_VAR(optype);
}
+
+ if (ret)
+ goto nope;
+
op_free(o);
if (type == OP_RV2GV)
return newGVOP(OP_GV, 0, (GV*)sv);
return newSVOP(OP_CONST, 0, sv);
- nope:
+ nope:
return o;
}
==== //depot/maint-5.8/perl/pod/perldiag.pod#85 (text) ====
Index: perl/pod/perldiag.pod
--- perl/pod/perldiag.pod#84~27315~ 2006-02-24 06:55:44.000000000 -0800
+++ perl/pod/perldiag.pod 2006-04-08 10:28:28.000000000 -0700
@@ -2754,6 +2754,11 @@
(P) The internal do_trans routines were called with invalid operational
data.
+=item panic: fold_constants JMPENV_PUSH returned %d
+
+(P) While attemtping folding constants an exception other than an C<eval>
+failure was caught.
+
=item panic: frexp
(P) The library function frexp() failed, making printf("%f") impossible.
==== //depot/maint-5.8/perl/pod/perltodo.pod#22 (text) ====
Index: perl/pod/perltodo.pod
--- perl/pod/perltodo.pod#21~27317~ 2006-02-24 08:36:54.000000000 -0800
+++ perl/pod/perltodo.pod 2006-04-08 10:28:28.000000000 -0700
@@ -541,13 +541,6 @@
debugger on a running Perl program, although I'm not sure how it would be
done." ssh and screen do this with named pipes in /tmp. Maybe we can too.
-=head2 Constant folding
-
-The peephole optimiser should trap errors during constant folding, and give
-up on the folding, rather than bailing out at compile time. It is quite
-possible that the unfoldable constant is in unreachable code, eg something
-akin to C<$a = 0/0 if 0;>
-
=head2 LVALUE functions for lists
The old perltodo notes that lvalue functions don't work for list or hash
==== //depot/maint-5.8/perl/t/comp/fold.t#1 (text) ====
Index: perl/t/comp/fold.t
--- /dev/null 2005-11-29 02:13:17.616583056 -0800
+++ perl/t/comp/fold.t 2006-04-08 10:28:28.000000000 -0700
@@ -0,0 +1,38 @@
+#!./perl
+
+BEGIN {
+ chdir 't';
+ @INC = '../lib';
+ require './test.pl';
+}
+use strict;
+use warnings;
+
+plan (8);
+
+# Historically constant folding was performed by evaluating the ops, and if
+# they threw an exception compilation failed. This was seen as buggy, because
+# even illegal constants in unreachable code would cause failure. So now
+# illegal expressions are reported at runtime, if the expression is reached,
+# making constant folding consistent with many other languages, and purely an
+# optimisation rather than a behaviour change.
+
+my $a;
+$a = eval '$b = 0/0 if 0; 3';
+is ($a, 3);
+is ($@, "");
+
+my $b = 0;
+$a = eval 'if ($b) {return sqrt -3} 3';
+is ($a, 3);
+is ($@, "");
+
+$a = eval q{
+ $b = eval q{if ($b) {return log 0} 4};
+ is ($b, 4);
+ is ($@, "");
+ 5;
+};
+is ($a, 5);
+is ($@, "");
+
End of Patch.
