This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Tidy up context type flags.
[perl5.git] / cop.h
diff --git a/cop.h b/cop.h
index ed57184..ccf910b 100644 (file)
--- a/cop.h
+++ b/cop.h
@@ -1,7 +1,7 @@
 /*    cop.h
  *
  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- *    2000, 2001, 2002, 2003, 2004, by Larry Wall and others
+ *    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 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.
@@ -100,7 +100,7 @@ typedef struct jmpenv JMPENV;
 #define JMPENV_PUSH(v) \
     STMT_START {                                                       \
        DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
-                        &cur_env, PL_top_env));                        \
+                        (void*)&cur_env, (void*)PL_top_env));                  \
        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);              \
@@ -113,7 +113,7 @@ typedef struct jmpenv JMPENV;
 #define JMPENV_POP \
     STMT_START {                                                       \
        DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p\n",    \
-                        PL_top_env, cur_env.je_prev));                 \
+                        (void*)PL_top_env, (void*)cur_env.je_prev));                   \
        PL_top_env = cur_env.je_prev;                                   \
     } STMT_END
 
@@ -132,9 +132,13 @@ typedef struct jmpenv JMPENV;
 #define CATCH_SET(v)           (PL_top_env->je_mustcatch = (v))
 
 
+#include "mydtrace.h"
 
 struct cop {
     BASEOP
+    /* 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 */
 #ifdef USE_ITHREADS
     char *     cop_stashpv;    /* package line was compiled in */
@@ -143,67 +147,89 @@ struct cop {
     HV *       cop_stash;      /* package line was compiled in */
     GV *       cop_filegv;     /* file the following line # is from */
 #endif
+    U32                cop_hints;      /* hints bits from pragmata */
     U32                cop_seq;        /* parse sequence number */
-    I32                cop_arybase;    /* array base this line was compiled with */
-    line_t      cop_line;       /* line # of this command */
-    SV *       cop_warnings;   /* lexical warnings bitmask */
-    SV *       cop_io;         /* lexical IO defaults */
+    /* Beware. mg.c and warnings.pl assume the type of this is STRLEN *:  */
+    STRLEN *   cop_warnings;   /* lexical warnings bitmask */
+    /* compile time state of %^H.  See the comment in op.c for how this is
+       used to recreate a hash to return from caller.  */
+    struct refcounted_he * cop_hints_hash;
 };
 
-#define Nullcop Null(COP*)
-
 #ifdef USE_ITHREADS
 #  define CopFILE(c)           ((c)->cop_file)
 #  define CopFILEGV(c)         (CopFILE(c) \
-                                ? gv_fetchfile(CopFILE(c)) : Nullgv)
+                                ? gv_fetchfile(CopFILE(c)) : NULL)
                                 
 #  ifdef NETWARE
 #    define CopFILE_set(c,pv)  ((c)->cop_file = savepv(pv))
+#    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savepv((pv),(l)))
 #  else
 #    define CopFILE_set(c,pv)  ((c)->cop_file = savesharedpv(pv))
+#    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savesharedpvn((pv),(l)))
 #  endif
 
 #  define CopFILESV(c)         (CopFILE(c) \
-                                ? GvSV(gv_fetchfile(CopFILE(c))) : Nullsv)
+                                ? GvSV(gv_fetchfile(CopFILE(c))) : NULL)
 #  define CopFILEAV(c)         (CopFILE(c) \
                                 ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
-#  define CopFILEAVx(c)                (assert(CopFILE(c)), \
+#  ifdef DEBUGGING
+#    define CopFILEAVx(c)      (assert(CopFILE(c)), \
                                   GvAV(gv_fetchfile(CopFILE(c))))
+#  else
+#    define CopFILEAVx(c)      (GvAV(gv_fetchfile(CopFILE(c))))
+#  endif
 #  define CopSTASHPV(c)                ((c)->cop_stashpv)
 
 #  ifdef NETWARE
-#    define CopSTASHPV_set(c,pv)       ((c)->cop_stashpv = ((pv) ? savepv(pv) : Nullch))
+#    define CopSTASHPV_set(c,pv)       ((c)->cop_stashpv = ((pv) ? savepv(pv) : NULL))
 #  else
 #    define CopSTASHPV_set(c,pv)       ((c)->cop_stashpv = savesharedpv(pv))
 #  endif
 
 #  define CopSTASH(c)          (CopSTASHPV(c) \
                                 ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
-#  define CopSTASH_set(c,hv)   CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : Nullch)
+#  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) = Nullch))
+#    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)
 #  define CopFILEGV_set(c,gv)  ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
 #  define CopFILE_set(c,pv)    CopFILEGV_set((c), gv_fetchfile(pv))
-#  define CopFILESV(c)         (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : Nullsv)
+#  define CopFILE_setn(c,pv,l) CopFILEGV_set((c), gv_fetchfile_flags((pv),(l),0))
+#  define CopFILESV(c)         (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : NULL)
 #  define CopFILEAV(c)         (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
-#  define CopFILEAVx(c)                (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
-#  define CopFILE(c)           (CopFILESV(c) ? SvPVX(CopFILESV(c)) : Nullch)
+#  ifdef DEBUGGING
+#    define CopFILEAVx(c)      (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
+#  else
+#    define CopFILEAVx(c)      (GvAV(CopFILEGV(c)))
+# endif
+#  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)) : Nullch)
+#  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) = Nullgv))
+#  define CopFILE_free(c)      (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
+#  define CopLABEL_free(c)     (Safefree(CopLABEL(c)),(CopLABEL(c) = NULL))
 
 #endif /* USE_ITHREADS */
 
@@ -220,22 +246,58 @@ struct cop {
 #  define OutCopFILE(c) CopFILE(c)
 #endif
 
+/* If $[ is non-zero, it's stored in cop_hints under the key "$[", and
+   HINT_ARYBASE is set to indicate this.
+   Setting it is ineficient due to the need to create 2 mortal SVs, but as
+   using $[ is highly discouraged, no sane Perl code will be using it.  */
+#define CopARYBASE_get(c)      \
+       ((CopHINTS_get(c) & HINT_ARYBASE)                               \
+        ? SvIV(Perl_refcounted_he_fetch(aTHX_ (c)->cop_hints_hash, 0,  \
+                                        "$[", 2, 0, 0))                \
+        : 0)
+#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,      \
+                                       newSVpvs_flags("$[", SVs_TEMP), \
+                                       sv_2mortal(newSViv(b)));        \
+       }                                                               \
+    } STMT_END
+
+/* FIXME NATIVE_HINTS if this is changed from op_private (see perl.h)  */
+#define CopHINTS_get(c)                ((c)->cop_hints + 0)
+#define CopHINTS_set(c, h)     STMT_START {                            \
+                                   (c)->cop_hints = (h);               \
+                               } STMT_END
+
 /*
  * Here we have some enormously heavy (or at least ponderous) wizardry.
  */
 
 /* subroutine context */
 struct block_sub {
+    OP *       retop;  /* op to execute on exit from sub */
+    /* Above here is the same for sub, format and eval.  */
     CV *       cv;
-    GV *       gv;
-    GV *       dfoutgv;
+    /* Above here is the same for sub and format.  */
     AV *       savearray;
     AV *       argarray;
-    long       olddepth;
-    U8         hasargs;
-    U8         lval;           /* XXX merge lval and hasargs? */
+    I32                olddepth;
     PAD                *oldcomppad;
+};
+
+
+/* format context */
+struct block_format {
     OP *       retop;  /* op to execute on exit from sub */
+    /* Above here is the same for sub, format and eval.  */
+    CV *       cv;
+    /* Above here is the same for sub and format.  */
+    GV *       gv;
+    GV *       dfoutgv;
 };
 
 /* base for the next two macros. Don't use directly.
@@ -243,35 +305,38 @@ struct block_sub {
  * decremented by LEAVESUB, the other by LEAVE. */
 
 #define PUSHSUB_BASE(cx)                                               \
+       ENTRY_PROBE(GvENAME(CvGV(cv)),                                  \
+               CopFILE((COP*)CvSTART(cv)),                             \
+               CopLINE((COP*)CvSTART(cv)));                            \
+                                                                       \
        cx->blk_sub.cv = cv;                                            \
        cx->blk_sub.olddepth = CvDEPTH(cv);                             \
-       cx->blk_sub.hasargs = hasargs;                                  \
-       cx->blk_sub.retop = Nullop;                                             \
+       cx->cx_type |= (hasargs) ? CXp_HASARGS : 0;                     \
+       cx->blk_sub.retop = NULL;                                       \
        if (!CvDEPTH(cv)) {                                             \
-           (void)SvREFCNT_inc(cv);                                     \
-           (void)SvREFCNT_inc(cv);                                     \
+           SvREFCNT_inc_simple_void_NN(cv);                            \
+           SvREFCNT_inc_simple_void_NN(cv);                            \
            SAVEFREESV(cv);                                             \
        }
 
 
 #define PUSHSUB(cx)                                                    \
        PUSHSUB_BASE(cx)                                                \
-       cx->blk_sub.lval = PL_op->op_private &                          \
+       cx->blk_u16 = PL_op->op_private &                               \
                              (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
 
 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
 #define PUSHSUB_DB(cx)                                                 \
        PUSHSUB_BASE(cx)                                                \
-       cx->blk_sub.lval = 0;
+       cx->blk_u16 = 0;
 
 
-#define PUSHFORMAT(cx)                                                 \
-       cx->blk_sub.cv = cv;                                            \
-       cx->blk_sub.gv = gv;                                            \
-       cx->blk_sub.retop = Nullop;                                     \
-       cx->blk_sub.hasargs = 0;                                        \
-       cx->blk_sub.dfoutgv = PL_defoutgv;                              \
-       (void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
+#define PUSHFORMAT(cx, retop)                                          \
+       cx->blk_format.cv = cv;                                         \
+       cx->blk_format.gv = gv;                                         \
+       cx->blk_format.retop = (retop);                                 \
+       cx->blk_format.dfoutgv = PL_defoutgv;                           \
+       SvREFCNT_inc_void(cx->blk_format.dfoutgv)
 
 #define POP_SAVEARRAY()                                                \
     STMT_START {                                                       \
@@ -284,17 +349,21 @@ struct block_sub {
 #define CLEAR_ARGARRAY(ary) \
     STMT_START {                                                       \
        AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
-       SvPV_set(ary, (char*)AvALLOC(ary));                             \
+       AvARRAY(ary) = AvALLOC(ary);                                    \
        AvFILLp(ary) = -1;                                              \
     } STMT_END
 
 #define POPSUB(cx,sv)                                                  \
     STMT_START {                                                       \
-       if (cx->blk_sub.hasargs) {                                      \
+       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)));           \
+                                                                       \
+       if (CxHASARGS(cx)) {                                            \
            POP_SAVEARRAY();                                            \
            /* abandon @_ if it got reified */                          \
            if (AvREAL(cx->blk_sub.argarray)) {                         \
-               SSize_t fill = AvFILLp(cx->blk_sub.argarray);           \
+               const SSize_t fill = AvFILLp(cx->blk_sub.argarray);     \
                SvREFCNT_dec(cx->blk_sub.argarray);                     \
                cx->blk_sub.argarray = newAV();                         \
                av_extend(cx->blk_sub.argarray, fill);                  \
@@ -307,7 +376,7 @@ struct block_sub {
        }                                                               \
        sv = (SV*)cx->blk_sub.cv;                                       \
        if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
-           sv = Nullsv;                                                \
+           sv = NULL;                                          \
     } STMT_END
 
 #define LEAVESUB(sv)                                                   \
@@ -317,37 +386,44 @@ struct block_sub {
     } STMT_END
 
 #define POPFORMAT(cx)                                                  \
-       setdefout(cx->blk_sub.dfoutgv);                                 \
-       SvREFCNT_dec(cx->blk_sub.dfoutgv);
+       setdefout(cx->blk_format.dfoutgv);                              \
+       SvREFCNT_dec(cx->blk_format.dfoutgv);
 
 /* eval context */
 struct block_eval {
-    I32                old_in_eval;
-    I32                old_op_type;
+    OP *       retop;  /* op to execute on exit from eval */
+    /* Above here is the same for sub, format and eval.  */
     SV *       old_namesv;
     OP *       old_eval_root;
     SV *       cur_text;
     CV *       cv;
-    OP *       retop;  /* op to execute on exit from eval */
     JMPENV *   cur_top_env; /* value of PL_top_env when eval CX created */
 };
 
+/* If we ever need more than 512 op types, change the shift from 7.
+   blku_gimme is actually also only 2 bits, so could be merged with something.
+*/
+
+#define CxOLD_IN_EVAL(cx)      (((cx)->blk_u16) & 0x7F)
+#define CxOLD_OP_TYPE(cx)      (((cx)->blk_u16) >> 7)
+
 #define PUSHEVAL(cx,n,fgv)                                             \
     STMT_START {                                                       \
-       cx->blk_eval.old_in_eval = PL_in_eval;                          \
-       cx->blk_eval.old_op_type = PL_op->op_type;                      \
-       cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);          \
+       assert(!(PL_in_eval & ~0x7F));                                  \
+       assert(!(PL_op->op_type & ~0x1FF));                             \
+       cx->blk_u16 = (PL_in_eval & 0x7F) | ((U16)PL_op->op_type << 7); \
+       cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : NULL);            \
        cx->blk_eval.old_eval_root = PL_eval_root;                      \
-       cx->blk_eval.cur_text = PL_linestr;                             \
-       cx->blk_eval.cv = Nullcv; /* set by doeval(), as applicable */  \
-       cx->blk_eval.retop = Nullop;                                    \
+       cx->blk_eval.cur_text = PL_parser ? PL_parser->linestr : NULL;  \
+       cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */    \
+       cx->blk_eval.retop = NULL;                                      \
        cx->blk_eval.cur_top_env = PL_top_env;                          \
     } STMT_END
 
 #define POPEVAL(cx)                                                    \
     STMT_START {                                                       \
-       PL_in_eval = cx->blk_eval.old_in_eval;                          \
-       optype = cx->blk_eval.old_op_type;                              \
+       PL_in_eval = CxOLD_IN_EVAL(cx);                                 \
+       optype = CxOLD_OP_TYPE(cx);                                     \
        PL_eval_root = cx->blk_eval.old_eval_root;                      \
        if (cx->blk_eval.old_namesv)                                    \
            sv_2mortal(cx->blk_eval.old_namesv);                        \
@@ -355,23 +431,40 @@ struct block_eval {
 
 /* loop context */
 struct block_loop {
-    char *     label;
     I32                resetsp;
-    OP *       redo_op;
-    OP *       next_op;
-    OP *       last_op;
+    LOOP *     my_op;  /* My op, that contains redo, next and last ops.  */
+    /* (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;
 #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;
 };
+/* 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)                                                 \
@@ -386,23 +479,32 @@ struct block_loop {
        if ((cx->blk_loop.iterdata = (idata)))                          \
            cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
        else                                                            \
-           cx->blk_loop.itersave = Nullsv;
+           cx->blk_loop.itersave = NULL;
 #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 = Nullsv;
+           cx->blk_loop.itersave = NULL;
+#endif
+#define CxLABEL(c)     (0 + (c)->blk_oldcop->cop_label)
+#define CxHASARGS(c)   (((c)->cx_type & CXp_HASARGS) == CXp_HASARGS)
+#define CxLVAL(c)      (0 + (c)->blk_u16)
+
+#ifdef USE_ITHREADS
+#  define PUSHLOOP_OP_NEXT             /* No need to do anything.  */
+#  define CX_LOOP_NEXTOP_GET(cx)       ((cx)->blk_loop.my_op->op_nextop + 0)
+#else
+#  define PUSHLOOP_OP_NEXT             cx->blk_loop.next_op = cLOOP->op_nextop
+#  define CX_LOOP_NEXTOP_GET(cx)       ((cx)->blk_loop.next_op + 0)
 #endif
 
 #define PUSHLOOP(cx, dat, s)                                           \
-       cx->blk_loop.label = PL_curcop->cop_label;                      \
        cx->blk_loop.resetsp = s - PL_stack_base;                       \
-       cx->blk_loop.redo_op = cLOOP->op_redoop;                        \
-       cx->blk_loop.next_op = cLOOP->op_nextop;                        \
-       cx->blk_loop.last_op = cLOOP->op_lastop;                        \
-       cx->blk_loop.iterlval = Nullsv;                                 \
+       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);
@@ -411,7 +513,7 @@ struct block_loop {
        SvREFCNT_dec(cx->blk_loop.iterlval);                            \
        if (CxITERVAR(cx)) {                                            \
             if (SvPADMY(cx->blk_loop.itersave)) {                      \
-               SV **s_v_p = CxITERVAR(cx);                             \
+               SV ** const s_v_p = CxITERVAR(cx);                      \
                sv_2mortal(*s_v_p);                                     \
                *s_v_p = cx->blk_loop.itersave;                         \
            }                                                           \
@@ -434,15 +536,18 @@ struct block_givwhen {
 
 /* context common to subroutines, evals and loops */
 struct block {
+    U8         blku_type;      /* what kind of context this is */
+    U8         blku_gimme;     /* is this block running in list context? */
+    U16                blku_u16;       /* used by block_sub and block_eval (so far) */
     I32                blku_oldsp;     /* stack pointer to copy stuff down to */
     COP *      blku_oldcop;    /* old curcop pointer */
     I32                blku_oldmarksp; /* mark stack index */
     I32                blku_oldscopesp;        /* scope stack index */
     PMOP *     blku_oldpm;     /* values of pattern match vars */
-    U8         blku_gimme;     /* is this block running in list context? */
 
     union {
        struct block_sub        blku_sub;
+       struct block_format     blku_format;
        struct block_eval       blku_eval;
        struct block_loop       blku_loop;
        struct block_givwhen    blku_givwhen;
@@ -454,7 +559,9 @@ struct block {
 #define blk_oldscopesp cx_u.cx_blk.blku_oldscopesp
 #define blk_oldpm      cx_u.cx_blk.blku_oldpm
 #define blk_gimme      cx_u.cx_blk.blku_gimme
+#define blk_u16                cx_u.cx_blk.blku_u16
 #define blk_sub                cx_u.cx_blk.blk_u.blku_sub
+#define blk_format     cx_u.cx_blk.blk_u.blku_format
 #define blk_eval       cx_u.cx_blk.blk_u.blku_eval
 #define blk_loop       cx_u.cx_blk.blk_u.blku_loop
 #define blk_givwhen    cx_u.cx_blk.blk_u.blku_givwhen
@@ -493,12 +600,13 @@ struct block {
 
 /* substitution context */
 struct subst {
+    U8         sbu_type;       /* what kind of context this is */
+    U8         sbu_once;       /* Actually both booleans, but U8/U16 */
+    U16                sbu_rxtainted;  /* matches struct block */
     I32                sbu_iters;
     I32                sbu_maxiters;
     I32                sbu_rflags;
     I32                sbu_oldsave;
-    bool       sbu_once;
-    bool       sbu_rxtainted;
     char *     sbu_orig;
     SV *       sbu_dstr;
     SV *       sbu_targ;
@@ -536,23 +644,25 @@ struct subst {
        cx->sb_s                = s,                                    \
        cx->sb_m                = m,                                    \
        cx->sb_strend           = strend,                               \
-       cx->sb_rxres            = Null(void*),                          \
+       cx->sb_rxres            = NULL,                                 \
        cx->sb_rx               = rx,                                   \
        cx->cx_type             = CXt_SUBST;                            \
-       rxres_save(&cx->sb_rxres, rx)
+       rxres_save(&cx->sb_rxres, rx);                                  \
+       (void)ReREFCNT_inc(rx)
 
 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                      \
-       rxres_free(&cx->sb_rxres)
+       rxres_free(&cx->sb_rxres);                                      \
+       ReREFCNT_dec(cx->sb_rx)
 
 struct context {
-    U32                cx_type;        /* what kind of context this is */
     union {
        struct block    cx_blk;
        struct subst    cx_subst;
     } cx_u;
 };
+#define cx_type cx_u.cx_subst.sbu_type
 
-#define CXTYPEMASK     0xff
+#define CXTYPEMASK     0xf
 #define CXt_NULL       0
 #define CXt_SUB                1
 #define CXt_EVAL       2
@@ -563,21 +673,26 @@ struct context {
 #define CXt_GIVEN      7
 #define CXt_WHEN       8
 
-/* private flags for CXt_SUB and CXt_NULL */
-#define CXp_MULTICALL  0x00000400      /* part of a multicall (so don't
-                                          tear down context on exit). */ 
+/* private flags for CXt_SUB and CXt_NULL
+   However, this is checked in many places which do not check the type, so
+   this bit needs to be kept clear for most everything else. For reasons I
+   haven't investigated, it can coexist with CXp_FOR_DEF */
+#define CXp_MULTICALL  0x10    /* part of a multicall (so don't
+                                  tear down context on exit). */ 
+
+/* private flags for CXt_SUB and CXt_FORMAT */
+#define CXp_HASARGS    0x20
 
 /* private flags for CXt_EVAL */
-#define CXp_REAL       0x00000100      /* truly eval'', not a lookalike */
-#define CXp_TRYBLOCK   0x00000200      /* eval{}, not eval'' or similar */
+#define CXp_REAL       0x20    /* truly eval'', not a lookalike */
+#define CXp_TRYBLOCK   0x40    /* eval{}, not eval'' or similar */
 
 /* private flags for CXt_LOOP */
-#define CXp_FOREACH    0x00000200      /* a foreach loop */
-#define CXp_FOR_DEF    0x00000400      /* foreach using $_ */
+#define CXp_FOR_DEF    0x10    /* foreach using $_ */
+#define CXp_FOREACH    0x20    /* a foreach loop */
 #ifdef USE_ITHREADS
-#  define CXp_PADVAR   0x00000100      /* itervar lives on pad, iterdata
-                                          has pad offset; if not set,
-                                          iterdata holds GV* */
+#  define CXp_PADVAR   0x40    /* itervar lives on pad, iterdata has pad
+                                  offset; if not set, iterdata holds GV* */
 #  define CxPADLOOP(c) (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
                         == (CXt_LOOP|CXp_PADVAR))
 #endif
@@ -585,13 +700,13 @@ struct context {
 #define CxTYPE(c)      ((c)->cx_type & CXTYPEMASK)
 #define CxMULTICALL(c) (((c)->cx_type & CXp_MULTICALL)                 \
                         == CXp_MULTICALL)
-#define CxREALEVAL(c)  (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
+#define CxREALEVAL(c)  (((c)->cx_type & (CXTYPEMASK|CXp_REAL))         \
                         == (CXt_EVAL|CXp_REAL))
-#define CxTRYBLOCK(c)  (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
+#define CxTRYBLOCK(c)  (((c)->cx_type & (CXTYPEMASK|CXp_TRYBLOCK))     \
                         == (CXt_EVAL|CXp_TRYBLOCK))
-#define CxFOREACH(c)   (((c)->cx_type & (CXt_LOOP|CXp_FOREACH))        \
+#define CxFOREACH(c)   (((c)->cx_type & (CXTYPEMASK|CXp_FOREACH))      \
                          == (CXt_LOOP|CXp_FOREACH))
-#define CxFOREACHDEF(c)        (((c)->cx_type & (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))\
+#define CxFOREACHDEF(c)        (((c)->cx_type & (CXTYPEMASK|CXp_FOREACH|CXp_FOR_DEF))\
                         == (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))
 
 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
@@ -629,17 +744,22 @@ L<perlcall>.
 =cut
 */
 
-#define G_SCALAR       0
-#define G_ARRAY                1
-#define G_VOID         128     /* skip this bit when adding flags below */
+#define G_SCALAR       2
+#define G_ARRAY                3
+#define G_VOID         1
+#define G_WANT         3
 
 /* extra flags for Perl_call_* routines */
-#define G_DISCARD      2       /* Call FREETMPS. */
-#define G_EVAL         4       /* Assume eval {} around subroutine call. */
-#define G_NOARGS       8       /* Don't construct a @_ array. */
-#define G_KEEPERR      16      /* Append errors to $@, don't overwrite it */
-#define G_NODEBUG      32      /* Disable debugging at toplevel.  */
-#define G_METHOD       64       /* Calling method. */
+#define G_DISCARD      4       /* Call FREETMPS.
+                                  Don't change this without consulting the
+                                  hash actions codes defined in hv.h */
+#define G_EVAL         8       /* Assume eval {} around subroutine call. */
+#define G_NOARGS       16      /* Don't construct a @_ array. */
+#define G_KEEPERR      32      /* Append errors to $@, don't overwrite it */
+#define G_NODEBUG      64      /* Disable debugging at toplevel.  */
+#define G_METHOD      128       /* Calling method. */
+#define G_FAKINGEVAL  256      /* Faking an eval context for call_sv or
+                                  fold_constants. */
 
 /* flag bits for PL_in_eval */
 #define EVAL_NULL      0       /* not in an eval */
@@ -667,11 +787,11 @@ L<perlcall>.
 struct stackinfo {
     AV *               si_stack;       /* stack for current runlevel */
     PERL_CONTEXT *     si_cxstack;     /* context stack for runlevel */
+    struct stackinfo * si_prev;
+    struct stackinfo * si_next;
     I32                        si_cxix;        /* current context index */
     I32                        si_cxmax;       /* maximum allocated index */
     I32                        si_type;        /* type of runlevel */
-    struct stackinfo * si_prev;
-    struct stackinfo * si_next;
     I32                        si_markoff;     /* offset where markstack begins for us.
                                         * currently used only with DEBUGGING,
                                         * but not #ifdef-ed for bincompat */
@@ -797,3 +917,13 @@ See L<perlcall/Lightweight Callbacks>.
        CATCH_SET(multicall_oldcatch);                                  \
        LEAVE;                                                          \
     } STMT_END
+
+/*
+ * Local variables:
+ * c-indentation-style: bsd
+ * c-basic-offset: 4
+ * indent-tabs-mode: t
+ * End:
+ *
+ * ex: set ts=8 sts=4 sw=4 noet:
+ */