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For Perl_magic_methcall() add G_UNDEF_FILL to fill the stack with &PL_sv_undef.
[perl5.git] / cop.h
diff --git a/cop.h b/cop.h
index 15de02f..f36d5ff 100644 (file)
--- a/cop.h
+++ b/cop.h
@@ -1,24 +1,25 @@
 /*    cop.h
  *
- *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- *    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, by Larry Wall and others
+ *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
+ *    2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 by Larry Wall and others
  *
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
  *
- * Control ops (cops) are one of the three ops OP_NEXTSTATE, OP_DBSTATE,
- * and OP_SETSTATE that (loosely speaking) are separate statements.
+ * Control ops (cops) are one of the two ops OP_NEXTSTATE and OP_DBSTATE,
+ * that (loosely speaking) are separate statements.
  * They hold information important for lexical state and error reporting.
  * At run time, PL_curcop is set to point to the most recently executed cop,
  * and thus can be used to determine our current state.
  */
 
 /* A jmpenv packages the state required to perform a proper non-local jump.
- * Note that there is a start_env initialized when perl starts, and top_env
- * points to this initially, so top_env should always be non-null.
+ * Note that there is a PL_start_env initialized when perl starts, and
+ * PL_top_env points to this initially, so PL_top_env should always be
+ * non-null.
  *
- * Existence of a non-null top_env->je_prev implies it is valid to call
- * longjmp() at that runlevel (we make sure start_env.je_prev is always
+ * Existence of a non-null PL_top_env->je_prev implies it is valid to call
+ * longjmp() at that runlevel (we make sure PL_start_env.je_prev is always
  * null to ensure this).
  *
  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
@@ -99,8 +100,11 @@ typedef struct jmpenv JMPENV;
 
 #define JMPENV_PUSH(v) \
     STMT_START {                                                       \
-       DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
-                        (void*)&cur_env, (void*)PL_top_env));                  \
+       DEBUG_l({                                                       \
+           int i = 0; JMPENV *p = PL_top_env;                          \
+           while (p) { i++; p = p->je_prev; }                          \
+           Perl_deb(aTHX_ "JUMPENV_PUSH level=%d at %s:%d\n",          \
+                        i,  __FILE__, __LINE__);})                     \
        cur_env.je_prev = PL_top_env;                                   \
        OP_REG_TO_MEM;                                                  \
        cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
@@ -112,13 +116,22 @@ typedef struct jmpenv JMPENV;
 
 #define JMPENV_POP \
     STMT_START {                                                       \
-       DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p\n",    \
-                        (void*)PL_top_env, (void*)cur_env.je_prev));                   \
+       DEBUG_l({                                                       \
+           int i = -1; JMPENV *p = PL_top_env;                         \
+           while (p) { i++; p = p->je_prev; }                          \
+           Perl_deb(aTHX_ "JUMPENV_POP level=%d at %s:%d\n",           \
+                        i, __FILE__, __LINE__);})                      \
+       assert(PL_top_env == &cur_env);                                 \
        PL_top_env = cur_env.je_prev;                                   \
     } STMT_END
 
 #define JMPENV_JUMP(v) \
     STMT_START {                                               \
+       DEBUG_l({                                               \
+           int i = -1; JMPENV *p = PL_top_env;                 \
+           while (p) { i++; p = p->je_prev; }                  \
+           Perl_deb(aTHX_ "JUMPENV_JUMP(%d) level=%d at %s:%d\n", \
+                        (int)v, i, __FILE__, __LINE__);})      \
        OP_REG_TO_MEM;                                          \
        if (PL_top_env->je_prev)                                \
            PerlProc_longjmp(PL_top_env->je_buf, (v));          \
@@ -129,7 +142,15 @@ typedef struct jmpenv JMPENV;
     } STMT_END
 
 #define CATCH_GET              (PL_top_env->je_mustcatch)
-#define CATCH_SET(v)           (PL_top_env->je_mustcatch = (v))
+#define CATCH_SET(v) \
+    STMT_START {                                                       \
+       DEBUG_l(                                                        \
+           Perl_deb(aTHX_                                              \
+               "JUMPLEVEL set catch %d => %d (for %p) at %s:%d\n",     \
+                PL_top_env->je_mustcatch, v, (void*)PL_top_env,        \
+                __FILE__, __LINE__);)                                  \
+       PL_top_env->je_mustcatch = (v);                                 \
+    } STMT_END
 
 
 #include "mydtrace.h"
@@ -139,7 +160,7 @@ struct cop {
     /* On LP64 putting this here takes advantage of the fact that BASEOP isn't
        an exact multiple of 8 bytes to save structure padding.  */
     line_t      cop_line;       /* line # of this command */
-    char *     cop_label;      /* label for this construct */
+    /* label for this construct is now stored in cop_hints_hash */
 #ifdef USE_ITHREADS
     char *     cop_stashpv;    /* package line was compiled in */
     char *     cop_file;       /* file name the following line # is from */
@@ -191,18 +212,12 @@ struct cop {
                                 ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
 #  define CopSTASH_set(c,hv)   CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : NULL)
 #  define CopSTASH_eq(c,hv)    ((hv) && stashpv_hvname_match(c,hv))
-#  define CopLABEL(c)          ((c)->cop_label)
-#  define CopLABEL_set(c,pv)   (CopLABEL(c) = (pv))
 #  ifdef NETWARE
 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
-#    define CopLABEL_free(c) SAVECOPLABEL_FREE(c)
-#    define CopLABEL_alloc(pv) ((pv)?savepv(pv):NULL)
 #  else
 #    define CopSTASH_free(c)   PerlMemShared_free(CopSTASHPV(c))
 #    define CopFILE_free(c)    (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = NULL))
-#    define CopLABEL_free(c)   (PerlMemShared_free(CopLABEL(c)),(CopLABEL(c) = NULL))
-#    define CopLABEL_alloc(pv) ((pv)?savesharedpv(pv):NULL)
 #  endif
 #else
 #  define CopFILEGV(c)         ((c)->cop_filegv)
@@ -219,19 +234,17 @@ struct cop {
 #  define CopFILE(c)           (CopFILEGV(c) && GvSV(CopFILEGV(c)) \
                                    ? SvPVX(GvSV(CopFILEGV(c))) : NULL)
 #  define CopSTASH(c)          ((c)->cop_stash)
-#  define CopLABEL(c)          ((c)->cop_label)
 #  define CopSTASH_set(c,hv)   ((c)->cop_stash = (hv))
 #  define CopSTASHPV(c)                (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : NULL)
    /* cop_stash is not refcounted */
 #  define CopSTASHPV_set(c,pv) CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
 #  define CopSTASH_eq(c,hv)    (CopSTASH(c) == (hv))
-#  define CopLABEL_alloc(pv)   ((pv)?savepv(pv):NULL)
-#  define CopLABEL_set(c,pv)   (CopLABEL(c) = (pv))
 #  define CopSTASH_free(c)     
 #  define CopFILE_free(c)      (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
-#  define CopLABEL_free(c)     (Safefree(CopLABEL(c)),(CopLABEL(c) = NULL))
 
 #endif /* USE_ITHREADS */
+#define CopLABEL(c)  Perl_fetch_cop_label(aTHX_ (c)->cop_hints_hash, NULL, NULL)
+#define CopLABEL_alloc(pv)     ((pv)?savepv(pv):NULL)
 
 #define CopSTASH_ne(c,hv)      (!CopSTASH_eq(c,hv))
 #define CopLINE(c)             ((c)->cop_line)
@@ -240,11 +253,7 @@ struct cop {
 #define CopLINE_set(c,l)       (CopLINE(c) = (l))
 
 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
-#ifdef MACOS_TRADITIONAL
-#  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
-#else
-#  define OutCopFILE(c) CopFILE(c)
-#endif
+#define OutCopFILE(c) CopFILE(c)
 
 /* If $[ is non-zero, it's stored in cop_hints under the key "$[", and
    HINT_ARYBASE is set to indicate this.
@@ -258,12 +267,17 @@ struct cop {
 #define CopARYBASE_set(c, b) STMT_START { \
        if (b || ((c)->cop_hints & HINT_ARYBASE)) {                     \
            (c)->cop_hints |= HINT_ARYBASE;                             \
-           if ((c) == &PL_compiling)                                   \
-               PL_hints |= HINT_LOCALIZE_HH | HINT_ARYBASE;            \
-           (c)->cop_hints_hash                                         \
-              = Perl_refcounted_he_new(aTHX_ (c)->cop_hints_hash,      \
+           if ((c) == &PL_compiling) {                                 \
+               SV *val = newSViv(b);                                   \
+               (void)hv_stores(GvHV(PL_hintgv), "$[", val);            \
+               mg_set(val);                                            \
+               PL_hints |= HINT_ARYBASE;                               \
+           } else {                                                    \
+               (c)->cop_hints_hash                                     \
+                  = Perl_refcounted_he_new(aTHX_ (c)->cop_hints_hash,  \
                                        newSVpvs_flags("$[", SVs_TEMP), \
                                        sv_2mortal(newSViv(b)));        \
+           }                                                           \
        }                                                               \
     } STMT_END
 
@@ -306,8 +320,8 @@ struct block_format {
 
 #define PUSHSUB_BASE(cx)                                               \
        ENTRY_PROBE(GvENAME(CvGV(cv)),                                  \
-               CopFILE((COP*)CvSTART(cv)),                             \
-               CopLINE((COP*)CvSTART(cv)));                            \
+               CopFILE((const COP *)CvSTART(cv)),                      \
+               CopLINE((const COP *)CvSTART(cv)));                     \
                                                                        \
        cx->blk_sub.cv = cv;                                            \
        cx->blk_sub.olddepth = CvDEPTH(cv);                             \
@@ -355,9 +369,9 @@ struct block_format {
 
 #define POPSUB(cx,sv)                                                  \
     STMT_START {                                                       \
-       RETURN_PROBE(GvENAME(CvGV((CV*)cx->blk_sub.cv)),                \
-               CopFILE((COP*)CvSTART((CV*)cx->blk_sub.cv)),            \
-               CopLINE((COP*)CvSTART((CV*)cx->blk_sub.cv)));           \
+       RETURN_PROBE(GvENAME(CvGV((const CV*)cx->blk_sub.cv)),          \
+               CopFILE((COP*)CvSTART((const CV*)cx->blk_sub.cv)),      \
+               CopLINE((COP*)CvSTART((const CV*)cx->blk_sub.cv)));     \
                                                                        \
        if (CxHASARGS(cx)) {                                            \
            POP_SAVEARRAY();                                            \
@@ -368,14 +382,14 @@ struct block_format {
                cx->blk_sub.argarray = newAV();                         \
                av_extend(cx->blk_sub.argarray, fill);                  \
                AvREIFY_only(cx->blk_sub.argarray);                     \
-               CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
+               CX_CURPAD_SV(cx->blk_sub, 0) = MUTABLE_SV(cx->blk_sub.argarray); \
            }                                                           \
            else {                                                      \
                CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
            }                                                           \
        }                                                               \
-       sv = (SV*)cx->blk_sub.cv;                                       \
-       if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
+       sv = MUTABLE_SV(cx->blk_sub.cv);                                \
+       if (sv && (CvDEPTH((const CV*)sv) = cx->blk_sub.olddepth))      \
            sv = NULL;                                          \
     } STMT_END
 
@@ -407,7 +421,7 @@ struct block_eval {
 #define CxOLD_IN_EVAL(cx)      (((cx)->blk_u16) & 0x7F)
 #define CxOLD_OP_TYPE(cx)      (((cx)->blk_u16) >> 7)
 
-#define PUSHEVAL(cx,n,fgv)                                             \
+#define PUSHEVAL(cx,n)                                                 \
     STMT_START {                                                       \
        assert(!(PL_in_eval & ~0x7F));                                  \
        assert(!(PL_op->op_type & ~0x1FF));                             \
@@ -436,59 +450,47 @@ struct block_loop {
     /* (except for non_ithreads we need to modify next_op in pp_ctl.c, hence
        why next_op is conditionally defined below.)  */
 #ifdef USE_ITHREADS
-    void *     iterdata;
-    PAD                *oldcomppad;
+    PAD                *oldcomppad; /* Also used for the GV, if targoffset is 0 */
+    /* This is also accesible via cx->blk_loop.my_op->op_targ */
+    PADOFFSET  targoffset;
 #else
     OP *       next_op;
     SV **      itervar;
 #endif
-    SV *       itersave;
-    /* (from inspection of source code) for a .. range of strings this is the
-       current string.  */
-    SV *       iterlval;
-    /* (from inspection of source code) for a foreach loop this is the array
-       being iterated over. For a .. range of numbers it's the current value.
-       A check is often made on the SvTYPE of iterary to determine whether
-       we are iterating over an array or a range. (numbers or strings)  */
-    AV *       iterary;
-    IV         iterix;
-    /* (from inspection of source code) for a .. range of numbers this is the
-       maximum value.  */
-    IV         itermax;
+    union {
+       struct { /* valid if type is LOOP_FOR or LOOP_PLAIN (but {NULL,0})*/
+           AV * ary; /* use the stack if this is NULL */
+           IV ix;
+       } ary;
+       struct { /* valid if type is LOOP_LAZYIV */
+           IV cur;
+           IV end;
+       } lazyiv;
+       struct { /* valid if type if LOOP_LAZYSV */
+           SV * cur;
+           SV * end; /* maxiumum value (or minimum in reverse) */
+       } lazysv;
+    } state_u;
 };
-/* It might be possible to squeeze this structure further. As best I can tell
-   itermax and iterlval are never used at the same time, so it might be possible
-   to make them into a union. However, I'm not confident that there are enough
-   flag bits/NULLable pointers in this structure alone to encode which is
-   active. There is, however, U8 of space free in struct block, which could be
-   used. Right now it may not be worth squeezing this structure further, as it's
-   the largest part of struct block, and currently struct block is 64 bytes on
-   an ILP32 system, which will give good cache alignment.
-*/
 
 #ifdef USE_ITHREADS
 #  define CxITERVAR(c)                                                 \
-       ((c)->blk_loop.iterdata                                         \
-        ? (CxPADLOOP(cx)                                               \
-           ? &CX_CURPAD_SV( (c)->blk_loop,                             \
-                   INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
-           : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
+       ((c)->blk_loop.oldcomppad                                       \
+        ? (CxPADLOOP(c)                                                \
+           ? &CX_CURPAD_SV( (c)->blk_loop, (c)->blk_loop.targoffset )  \
+           : &GvSV((GV*)(c)->blk_loop.oldcomppad))                     \
         : (SV**)NULL)
-#  define CX_ITERDATA_SET(cx,idata)                                    \
-       CX_CURPAD_SAVE(cx->blk_loop);                                   \
-       if ((cx->blk_loop.iterdata = (idata)))                          \
-           cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
+#  define CX_ITERDATA_SET(cx,idata,o)                                  \
+       if ((cx->blk_loop.targoffset = (o)))                            \
+           CX_CURPAD_SAVE(cx->blk_loop);                               \
        else                                                            \
-           cx->blk_loop.itersave = NULL;
+           cx->blk_loop.oldcomppad = (idata);
 #else
 #  define CxITERVAR(c)         ((c)->blk_loop.itervar)
-#  define CX_ITERDATA_SET(cx,ivar)                                     \
-       if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
-           cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
-       else                                                            \
-           cx->blk_loop.itersave = NULL;
+#  define CX_ITERDATA_SET(cx,ivar,o)                                   \
+       cx->blk_loop.itervar = (SV**)(ivar);
 #endif
-#define CxLABEL(c)     (0 + (c)->blk_oldcop->cop_label)
+#define CxLABEL(c)     (0 + CopLABEL((c)->blk_oldcop))
 #define CxHASARGS(c)   (((c)->cx_type & CXp_HASARGS) == CXp_HASARGS)
 #define CxLVAL(c)      (0 + (c)->blk_u16)
 
@@ -504,33 +506,25 @@ struct block_loop {
        cx->blk_loop.resetsp = s - PL_stack_base;                       \
        cx->blk_loop.my_op = cLOOP;                                     \
        PUSHLOOP_OP_NEXT;                                               \
-       cx->blk_loop.iterlval = NULL;                                   \
-       cx->blk_loop.iterary = NULL;                                    \
-       CX_ITERDATA_SET(cx,NULL);
+       cx->blk_loop.state_u.ary.ary = NULL;                            \
+       cx->blk_loop.state_u.ary.ix = 0;                                \
+       CX_ITERDATA_SET(cx, NULL, 0);
 
-#define PUSHLOOP_FOR(cx, dat, s)                                       \
+#define PUSHLOOP_FOR(cx, dat, s, offset)                               \
        cx->blk_loop.resetsp = s - PL_stack_base;                       \
        cx->blk_loop.my_op = cLOOP;                                     \
        PUSHLOOP_OP_NEXT;                                               \
-       cx->blk_loop.iterlval = NULL;                                   \
-       cx->blk_loop.iterary = NULL;                                    \
-       cx->blk_loop.iterix = -1;                                       \
-       CX_ITERDATA_SET(cx,dat);
+       cx->blk_loop.state_u.ary.ary = NULL;                            \
+       cx->blk_loop.state_u.ary.ix = 0;                                \
+       CX_ITERDATA_SET(cx, dat, offset);
 
 #define POPLOOP(cx)                                                    \
-       SvREFCNT_dec(cx->blk_loop.iterlval);                            \
-       if (CxITERVAR(cx)) {                                            \
-            if (SvPADMY(cx->blk_loop.itersave)) {                      \
-               SV ** const s_v_p = CxITERVAR(cx);                      \
-               sv_2mortal(*s_v_p);                                     \
-               *s_v_p = cx->blk_loop.itersave;                         \
-           }                                                           \
-           else {                                                      \
-               SvREFCNT_dec(cx->blk_loop.itersave);                    \
-           }                                                           \
+       if (CxTYPE(cx) == CXt_LOOP_LAZYSV) {                            \
+           SvREFCNT_dec(cx->blk_loop.state_u.lazysv.cur);              \
+           SvREFCNT_dec(cx->blk_loop.state_u.lazysv.end);              \
        }                                                               \
-       if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
-           SvREFCNT_dec(cx->blk_loop.iterary);
+       if (CxTYPE(cx) == CXt_LOOP_FOR)                                 \
+           SvREFCNT_dec(cx->blk_loop.state_u.ary.ary);
 
 /* given/when context */
 struct block_givwhen {
@@ -574,6 +568,16 @@ struct block {
 #define blk_loop       cx_u.cx_blk.blk_u.blku_loop
 #define blk_givwhen    cx_u.cx_blk.blk_u.blku_givwhen
 
+#define DEBUG_CX(action)                                               \
+    DEBUG_l(WITH_THX(                                                  \
+       Perl_deb(aTHX_ "CX %ld %s %s (scope %ld,%ld) at %s:%d\n",       \
+                   (long)cxstack_ix,                                   \
+                   action,                                             \
+                   PL_block_type[CxTYPE(&cxstack[cxstack_ix])],        \
+                   (long)PL_scopestack_ix,                             \
+                   (long)(cxstack[cxstack_ix].blk_oldscopesp),         \
+                   __FILE__, __LINE__)));
+
 /* Enter a block. */
 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],           \
        cx->cx_type             = t,                                    \
@@ -583,28 +587,27 @@ struct block {
        cx->blk_oldscopesp      = PL_scopestack_ix,                     \
        cx->blk_oldpm           = PL_curpm,                             \
        cx->blk_gimme           = (U8)gimme;                            \
-       DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
-                   (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
+       DEBUG_CX("PUSH");
 
 /* Exit a block (RETURN and LAST). */
-#define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                   \
+#define POPBLOCK(cx,pm)                                                        \
+       DEBUG_CX("POP");                                                \
+       cx = &cxstack[cxstack_ix--],                                    \
        newsp            = PL_stack_base + cx->blk_oldsp,               \
        PL_curcop        = cx->blk_oldcop,                              \
        PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
        PL_scopestack_ix = cx->blk_oldscopesp,                          \
        pm               = cx->blk_oldpm,                               \
-       gimme            = cx->blk_gimme;                               \
-       DEBUG_SCOPE("POPBLOCK");                                        \
-       DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
-                   (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
+       gimme            = cx->blk_gimme;
 
 /* Continue a block elsewhere (NEXT and REDO). */
-#define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                       \
+#define TOPBLOCK(cx)                                                   \
+       DEBUG_CX("TOP");                                                \
+       cx  = &cxstack[cxstack_ix],                                     \
        PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
        PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
        PL_scopestack_ix = cx->blk_oldscopesp,                          \
-       PL_curpm         = cx->blk_oldpm;                               \
-       DEBUG_SCOPE("TOPBLOCK");
+       PL_curpm         = cx->blk_oldpm;
 
 /* substitution context */
 struct subst {
@@ -638,7 +641,8 @@ struct subst {
 #define sb_rxres       cx_u.cx_subst.sbu_rxres
 #define sb_rx          cx_u.cx_subst.sbu_rx
 
-#define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                        \
+#ifdef PERL_CORE
+#  define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],              \
        cx->sb_iters            = iters,                                \
        cx->sb_maxiters         = maxiters,                             \
        cx->sb_rflags           = r_flags,                              \
@@ -656,11 +660,12 @@ struct subst {
        rxres_save(&cx->sb_rxres, rx);                                  \
        (void)ReREFCNT_inc(rx)
 
-#define CxONCE(cx)             ((cx)->cx_type & CXp_ONCE)
-
-#define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                      \
+#  define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                    \
        rxres_free(&cx->sb_rxres);                                      \
        ReREFCNT_dec(cx->sb_rx)
+#endif
+
+#define CxONCE(cx)             ((cx)->cx_type & CXp_ONCE)
 
 struct context {
     union {
@@ -670,19 +675,27 @@ struct context {
 };
 #define cx_type cx_u.cx_subst.sbu_type
 
+/* If you re-order these, there is also an array of uppercase names in perl.h
+   and a static array of context names in pp_ctl.c  */
 #define CXTYPEMASK     0xf
 #define CXt_NULL       0
-#define CXt_SUB                1
-#define CXt_EVAL       2
-#define CXt_WHEN       3
-#define CXt_SUBST      4
-#define CXt_BLOCK      5
-#define CXt_FORMAT     6
-#define CXt_GIVEN      7
-#define CXt_LOOP_PLAIN 8
-#define CXt_LOOP_FOR   9
-#define CXt_LOOP_RES1  10
-#define CXt_LOOP_RES2  11
+#define CXt_WHEN       1
+#define CXt_BLOCK      2
+/* When micro-optimising :-) keep GIVEN next to the LOOPs, as these 5 share a
+   jump table in pp_ctl.c
+   The first 4 don't have a 'case' in at least one switch statement in pp_ctl.c
+*/
+#define CXt_GIVEN      3
+/* This is first so that CXt_LOOP_FOR|CXt_LOOP_LAZYIV is CXt_LOOP_LAZYIV */
+#define CXt_LOOP_FOR   4
+#define CXt_LOOP_PLAIN 5
+#define CXt_LOOP_LAZYSV        6
+#define CXt_LOOP_LAZYIV        7
+#define CXt_SUB                8
+#define CXt_FORMAT      9
+#define CXt_EVAL       10
+#define CXt_SUBST      11
+/* SUBST doesn't feature in all switch statements.  */
 
 /* private flags for CXt_SUB and CXt_NULL
    However, this is checked in many places which do not check the type, so
@@ -701,15 +714,14 @@ struct context {
 /* private flags for CXt_LOOP */
 #define CXp_FOR_DEF    0x10    /* foreach using $_ */
 #ifdef USE_ITHREADS
-#  define CXp_PADVAR   0x20    /* itervar lives on pad, iterdata has pad
-                                  offset; if not set, iterdata holds GV* */
-#  define CxPADLOOP(c) (CxTYPE_is_LOOP(c) && ((c)->cx_type & (CXp_PADVAR)))
+#  define CxPADLOOP(c) ((c)->blk_loop.targoffset)
 #endif
+
 /* private flags for CXt_SUBST */
 #define CXp_ONCE       0x10    /* What was sbu_once in struct subst */
 
 #define CxTYPE(c)      ((c)->cx_type & CXTYPEMASK)
-#define CxTYPE_is_LOOP(c)      (((c)->cx_type & 0xC) == 0x8)
+#define CxTYPE_is_LOOP(c)      (((c)->cx_type & 0xC) == 0x4)
 #define CxMULTICALL(c) (((c)->cx_type & CXp_MULTICALL)                 \
                         == CXp_MULTICALL)
 #define CxREALEVAL(c)  (((c)->cx_type & (CXTYPEMASK|CXp_REAL))         \
@@ -771,6 +783,9 @@ L<perlcall>.
 #define G_METHOD      128       /* Calling method. */
 #define G_FAKINGEVAL  256      /* Faking an eval context for call_sv or
                                   fold_constants. */
+#define G_UNDEF_FILL  512      /* Fill the stack with &PL_sv_undef
+                                  A special case for UNSHIFT in
+                                  Perl_magic_methcall().  */
 
 /* flag bits for PL_in_eval */
 #define EVAL_NULL      0       /* not in an eval */
@@ -824,6 +839,11 @@ typedef struct stackinfo PERL_SI;
 #define PUSHSTACKi(type) \
     STMT_START {                                                       \
        PERL_SI *next = PL_curstackinfo->si_next;                       \
+       DEBUG_l({                                                       \
+           int i = 0; PERL_SI *p = PL_curstackinfo;                    \
+           while (p) { i++; p = p->si_prev; }                          \
+           Perl_deb(aTHX_ "push STACKINFO %d at %s:%d\n",              \
+                        i, __FILE__, __LINE__);})                      \
        if (!next) {                                                    \
            next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
            next->si_prev = PL_curstackinfo;                            \
@@ -845,6 +865,11 @@ typedef struct stackinfo PERL_SI;
     STMT_START {                                                       \
        dSP;                                                            \
        PERL_SI * const prev = PL_curstackinfo->si_prev;                \
+       DEBUG_l({                                                       \
+           int i = -1; PERL_SI *p = PL_curstackinfo;                   \
+           while (p) { i++; p = p->si_prev; }                          \
+           Perl_deb(aTHX_ "pop  STACKINFO %d at %s:%d\n",              \
+                        i, __FILE__, __LINE__);})                      \
        if (!prev) {                                                    \
            PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
            my_exit(1);                                                 \
@@ -902,6 +927,7 @@ See L<perlcall/Lightweight Callbacks>.
        multicall_oldcatch = CATCH_GET;                                 \
        SAVETMPS; SAVEVPTR(PL_op);                                      \
        CATCH_SET(TRUE);                                                \
+       PUSHSTACKi(PERLSI_SORT);                                        \
        PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
        PUSHSUB(cx);                                                    \
        if (++CvDEPTH(cv) >= 2) {                                       \
@@ -925,8 +951,10 @@ See L<perlcall/Lightweight Callbacks>.
        LEAVESUB(multicall_cv);                                         \
        CvDEPTH(multicall_cv)--;                                        \
        POPBLOCK(cx,PL_curpm);                                          \
+       POPSTACK;                                                       \
        CATCH_SET(multicall_oldcatch);                                  \
        LEAVE;                                                          \
+       SPAGAIN;                                                        \
     } STMT_END
 
 /*