initial implementation of lvalue subroutines (slightly fixed

[p5sagit/p5-mst-13.2.git] / pp_hot.c

diff --git a/pp_hot.c b/pp_hot.c
index 78f07a1..bb034e5 100644 (file)
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -1921,13 +1921,16 @@ PP(pp_leavesub)
                    *MARK = SvREFCNT_inc(TOPs);
                    FREETMPS;
                    sv_2mortal(*MARK);
-               } else {
+               }
+               else {
                    FREETMPS;
                    *MARK = sv_mortalcopy(TOPs);
                }
-           } else
+           }
+           else
                *MARK = SvTEMP(TOPs) ? TOPs : sv_mortalcopy(TOPs);
-       } else {
+       }
+       else {
            MEXTEND(MARK, 0);
            *MARK = &PL_sv_undef;
        }
@@ -1950,6 +1953,138 @@ PP(pp_leavesub)
     return pop_return();
 }
 
+/* This duplicates the above code because the above code must not
+ * get any slower by more conditions */
+PP(pp_leavesublv)
+{
+    djSP;
+    SV **mark;
+    SV **newsp;
+    PMOP *newpm;
+    I32 gimme;
+    register PERL_CONTEXT *cx;
+    struct block_sub cxsub;
+
+    POPBLOCK(cx,newpm);
+    POPSUB1(cx);       /* Delay POPSUB2 until stack values are safe */
+ 
+    TAINT_NOT;
+
+    if (cx->blk_sub.lval & OPpENTERSUB_INARGS) {
+       /* We are an argument to a function or grep().
+        * This kind of lvalueness was legal before lvalue
+        * subroutines too, so be backward compatible:
+        * cannot report errors.  */
+
+       /* Scalar context *is* possible, on the LHS of -> only,
+        * as in f()->meth().  But this is not an lvalue. */
+       if (gimme == G_SCALAR)
+           goto temporise;
+       if (gimme == G_ARRAY) {
+           if (!CvLVALUE(cxsub.cv))
+               goto temporise_array;
+           EXTEND_MORTAL(SP - newsp);
+           for (mark = newsp + 1; mark <= SP; mark++) {
+               if (SvTEMP(*mark))
+                   /* empty */ ;
+               else if (SvFLAGS(*mark) & (SVs_PADTMP | SVf_READONLY))
+                   *mark = sv_mortalcopy(*mark);
+               else {
+                   /* Can be a localized value subject to deletion. */
+                   PL_tmps_stack[++PL_tmps_ix] = *mark;
+                   SvREFCNT_inc(*mark);
+               }
+           }
+       }
+    }
+    else if (cx->blk_sub.lval) {     /* Leave it as it is if we can. */
+       /* Here we go for robustness, not for speed, so we change all
+        * the refcounts so the caller gets a live guy. Cannot set
+        * TEMP, so sv_2mortal is out of question. */
+       if (!CvLVALUE(cxsub.cv))
+           Perl_croak(aTHX_ "Can't modify non-lvalue subroutine call");
+       if (gimme == G_SCALAR) {
+           MARK = newsp + 1;
+           EXTEND_MORTAL(1);
+           if (MARK == SP) {
+               if (SvFLAGS(TOPs) & (SVs_TEMP | SVs_PADTMP | SVf_READONLY))
+                   Perl_croak(aTHX_ "Can't return a %s from lvalue subroutine",
+                       SvREADONLY(TOPs) ? "readonly value" : "temporary");
+               else {                  /* Can be a localized value
+                                        * subject to deletion. */
+                   PL_tmps_stack[++PL_tmps_ix] = *mark;
+                   SvREFCNT_inc(*mark);
+               }
+           }
+           else                        /* Should not happen? */
+               Perl_croak(aTHX_ "%s returned from lvalue subroutine in scalar context",
+                   (MARK > SP ? "Empty array" : "Array"));
+           SP = MARK;
+       }
+       else if (gimme == G_ARRAY) {
+           EXTEND_MORTAL(SP - newsp);
+           for (mark = newsp + 1; mark <= SP; mark++) {
+               if (SvFLAGS(*mark) & (SVs_TEMP | SVs_PADTMP | SVf_READONLY))
+               /* Might be flattened array after $#array =  */
+               Perl_croak(aTHX_ "Can't return %s from lvalue subroutine",
+                       (*mark != &PL_sv_undef)
+                       ? (SvREADONLY(TOPs)
+                           ? "a readonly value" : "a temporary")
+                       : "an uninitialized value");
+               else {
+                   mortalize:
+                   /* Can be a localized value subject to deletion. */
+                   PL_tmps_stack[++PL_tmps_ix] = *mark;
+                   SvREFCNT_inc(*mark);
+               }
+           }
+       }
+    }
+    else {
+       if (gimme == G_SCALAR) {
+         temporise:
+           MARK = newsp + 1;
+           if (MARK <= SP) {
+               if (cxsub.cv && CvDEPTH(cxsub.cv) > 1) {
+                   if (SvTEMP(TOPs)) {
+                       *MARK = SvREFCNT_inc(TOPs);
+                       FREETMPS;
+                       sv_2mortal(*MARK);
+                   }
+                   else {
+                       FREETMPS;
+                       *MARK = sv_mortalcopy(TOPs);
+                   }
+               }
+               else
+                   *MARK = SvTEMP(TOPs) ? TOPs : sv_mortalcopy(TOPs);
+           }
+           else {
+               MEXTEND(MARK, 0);
+               *MARK = &PL_sv_undef;
+           }
+           SP = MARK;
+       }
+       else if (gimme == G_ARRAY) {
+         temporise_array:
+           for (MARK = newsp + 1; MARK <= SP; MARK++) {
+               if (!SvTEMP(*MARK)) {
+                   *MARK = sv_mortalcopy(*MARK);
+                   TAINT_NOT;  /* Each item is independent */
+               }
+           }
+       }
+    }
+    PUTBACK;
+    
+    POPSUB2();         /* Stack values are safe: release CV and @_ ... */
+    PL_curpm = newpm;  /* ... and pop $1 et al */
+
+    LEAVE;
+    return pop_return();
+}
+
+
 STATIC CV *
 S_get_db_sub(pTHX_ SV **svp, CV *cv)
 {
@@ -2193,7 +2328,8 @@ try_autoload:
                            "entersub: %p grabbing %p:%s in stash %s\n",
                            thr, cv, SvPEEK((SV*)cv), CvSTASH(cv) ?
                                HvNAME(CvSTASH(cv)) : "(none)"));
-           } else {
+           }
+           else {
                /* Make a new clone. */
                CV *clonecv;
                SvREFCNT_inc(cv); /* don't let it vanish from under us */