add CvEVAL_COMPILED() flag and fix closure bug.

cv.h

@@ -140,6 +140,7 @@ See L<perlguts/Autoloading with XSUBs>.
                                    CVf_METHOD; now CVf_NOWARN_AMBIGUOUS */
 #define CVf_XS_RCSTACK  0x200000 /* the XS function understands a
                                     reference-counted stack */
+#define CVf_EVAL_COMPILED 0x400000 /* an eval CV is fully compiled */
 
 /* This symbol for optimised communication between toke.c and op.c: */
 #define CVf_BUILTIN_ATTRS	(CVf_NOWARN_AMBIGUOUS|CVf_LVALUE|CVf_ANONCONST)
@@ -266,6 +267,10 @@ Helper macro to turn off the C<CvREFCOUNTED_ANYSV> flag.
 #define CvXS_RCSTACK_on(cv)     (CvFLAGS(cv) |= CVf_XS_RCSTACK)
 #define CvXS_RCSTACK_off(cv)    (CvFLAGS(cv) &= ~CVf_XS_RCSTACK)
 
+#define CvEVAL_COMPILED(cv)     (CvFLAGS(cv) & CVf_EVAL_COMPILED)
+#define CvEVAL_COMPILED_on(cv)  (CvFLAGS(cv) |= CVf_EVAL_COMPILED)
+#define CvEVAL_COMPILED_off(cv) (CvFLAGS(cv) &= ~CVf_EVAL_COMPILED)
+
 /* Back-compat */
 #ifndef PERL_CORE
 #  define CVf_METHOD            CVf_NOWARN_AMBIGUOUS

dump.c

@@ -1782,7 +1782,8 @@ const struct flag_to_name cv_flags_names[] = {
     {CVf_SIGNATURE,        "SIGNATURE,"},
     {CVf_REFCOUNTED_ANYSV, "REFCOUNTED_ANYSV,"},
     {CVf_IsMETHOD,         "IsMETHOD,"},
-    {CVf_XS_RCSTACK,       "XS_RCSTACK,"}
+    {CVf_XS_RCSTACK,       "XS_RCSTACK,"},
+    {CVf_EVAL_COMPILED,    "EVAL_COMPILED,"},
 };
 
 const struct flag_to_name hv_flags_names[] = {

op.c

@@ -4702,6 +4702,7 @@ Perl_newPROG(pTHX_ OP *o)
         SAVEFREEOP(o);
         ENTER;
         S_process_optree(aTHX_ NULL, PL_eval_root, start);
+        CvEVAL_COMPILED_on(PL_compcv); /* this eval is now fully compiled */
         LEAVE;
         PL_savestack_ix = i;
     }

pad.c

@@ -1079,8 +1079,9 @@ index into the parent pad.
 */
 
 /* the CV has finished being compiled. This is not a sufficient test for
- * all CVs (eg XSUBs), but suffices for the CVs found in a lexical chain */
-#define CvCOMPILED(cv)	CvROOT(cv)
+ * all CVs (eg XSUBs), but suffices for the CVs found in a lexical chain.
+ * Note that a fully-compiled eval doesn't get CvROOT() set. */
+#define CvCOMPILED(cv)	(CvROOT(cv) || CvEVAL_COMPILED(cv))
 
 /* the CV does late binding of its lexicals */
 #define CvLATE(cv) (CvANON(cv) || CvCLONE(cv) || SvTYPE(cv) == SVt_PVFM)

t/op/eval.t

@@ -6,7 +6,7 @@ BEGIN {
     set_up_inc('../lib');
 }
 
-plan(tests => 169);
+plan(tests => 170);
 
 eval 'pass();';
 
@@ -768,3 +768,20 @@ pass("eval in freed package does not crash");
         );
     }
 }
+
+# The first inner eval finds the $v and adds a fake entry to the
+# outer eval's pad. The second inner eval finds the fake $c entry,
+# but was incorrectly concluding that the outer eval was in fact a
+# non-live anon prototype and issuing the warning
+# 'Variable "$v" is not available'/
+
+{
+    use warnings;
+    my $w = 0;
+    local $SIG{__WARN__} = sub { $w++ };
+    sub {
+        my $v;
+        eval q( eval '$v'; eval '$v';);
+    }->();
+    is($w, 0, "nested eval and closure");
+}