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   1  /*    pad.h
   2   *
   3   *    Copyright (C) 2002, 2003, 2005, 2006, 2007 by Larry Wall and others
   4   *
   5   *    You may distribute under the terms of either the GNU General Public
   6   *    License or the Artistic License, as specified in the README file.
   7   *
   8   * This file defines the types and macros associated with the API for
   9   * manipulating scratchpads, which are used by perl to store lexical
  10   * variables, op targets and constants.
  11   */
  12  
  13  
  14  
  15  
  16  /* a padlist is currently just an AV; but that might change,
  17   * so hide the type. Ditto a pad.  */
  18  
  19  typedef AV PADLIST;
  20  typedef AV PAD;
  21  
  22  
  23  /* offsets within a pad */
  24  
  25  #if PTRSIZE == 4
  26  typedef U32TYPE PADOFFSET;
  27  #else
  28  #   if PTRSIZE == 8
  29  typedef U64TYPE PADOFFSET;
  30  #   endif
  31  #endif
  32  #define NOT_IN_PAD ((PADOFFSET) -1)
  33  
  34  /* B.xs needs these for the benefit of B::Deparse */ 
  35  /* Low range end is exclusive (valid from the cop seq after this one) */
  36  /* High range end is inclusive (valid up to this cop seq) */
  37  
  38  #if defined (DEBUGGING) && defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
  39  #  define COP_SEQ_RANGE_LOW(sv)                        \
  40      (({ SV *const _svi = (SV *) (sv);                \
  41        assert(SvTYPE(_svi) == SVt_NV || SvTYPE(_svi) >= SVt_PVNV);    \
  42        assert(SvTYPE(_svi) != SVt_PVAV);                \
  43        assert(SvTYPE(_svi) != SVt_PVHV);                \
  44        assert(SvTYPE(_svi) != SVt_PVCV);                \
  45        assert(SvTYPE(_svi) != SVt_PVFM);                \
  46        assert(!isGV_with_GP(_svi));                    \
  47        ((XPVNV*) SvANY(_svi))->xnv_u.xpad_cop_seq.xlow;        \
  48       }))
  49  #  define COP_SEQ_RANGE_HIGH(sv)                    \
  50      (({ SV *const _svi = (SV *) (sv);                \
  51        assert(SvTYPE(_svi) == SVt_NV || SvTYPE(_svi) >= SVt_PVNV);    \
  52        assert(SvTYPE(_svi) != SVt_PVAV);                \
  53        assert(SvTYPE(_svi) != SVt_PVHV);                \
  54        assert(SvTYPE(_svi) != SVt_PVCV);                \
  55        assert(SvTYPE(_svi) != SVt_PVFM);                \
  56        assert(!isGV_with_GP(_svi));                    \
  57        ((XPVNV*) SvANY(_svi))->xnv_u.xpad_cop_seq.xhigh;        \
  58       }))
  59  #  define PARENT_PAD_INDEX(sv)                        \
  60      (({ SV *const _svi = (SV *) (sv);                \
  61        assert(SvTYPE(_svi) == SVt_NV || SvTYPE(_svi) >= SVt_PVNV);    \
  62        assert(SvTYPE(_svi) != SVt_PVAV);                \
  63        assert(SvTYPE(_svi) != SVt_PVHV);                \
  64        assert(SvTYPE(_svi) != SVt_PVCV);                \
  65        assert(SvTYPE(_svi) != SVt_PVFM);                \
  66        assert(!isGV_with_GP(_svi));                    \
  67        ((XPVNV*) SvANY(_svi))->xnv_u.xpad_cop_seq.xlow;        \
  68       }))
  69  #  define PARENT_FAKELEX_FLAGS(sv)                    \
  70      (({ SV *const _svi = (SV *) (sv);                \
  71        assert(SvTYPE(_svi) == SVt_NV || SvTYPE(_svi) >= SVt_PVNV);    \
  72        assert(SvTYPE(_svi) != SVt_PVAV);                \
  73        assert(SvTYPE(_svi) != SVt_PVHV);                \
  74        assert(SvTYPE(_svi) != SVt_PVCV);                \
  75        assert(SvTYPE(_svi) != SVt_PVFM);                \
  76        assert(!isGV_with_GP(_svi));                    \
  77        ((XPVNV*) SvANY(_svi))->xnv_u.xpad_cop_seq.xhigh;        \
  78       }))
  79  #else
  80  #  define COP_SEQ_RANGE_LOW(sv)        \
  81      (0 + (((XPVNV*) SvANY(sv))->xnv_u.xpad_cop_seq.xlow))
  82  #  define COP_SEQ_RANGE_HIGH(sv)    \
  83      (0 + (((XPVNV*) SvANY(sv))->xnv_u.xpad_cop_seq.xhigh))
  84  
  85  
  86  #  define PARENT_PAD_INDEX(sv)        \
  87      (0 + (((XPVNV*) SvANY(sv))->xnv_u.xpad_cop_seq.xlow))
  88  #  define PARENT_FAKELEX_FLAGS(sv)    \
  89      (0 + (((XPVNV*) SvANY(sv))->xnv_u.xpad_cop_seq.xhigh))
  90  #endif
  91  
  92  /* Flags set in the SvIVX field of FAKE namesvs */
  93      
  94  #define PAD_FAKELEX_ANON   1 /* the lex is declared in an ANON, or ... */
  95  #define PAD_FAKELEX_MULTI  2 /* the lex can be instantiated multiple times */
  96  
  97  /* flags for the pad_new() function */
  98  
  99  #define padnew_CLONE    1    /* this pad is for a cloned CV */
 100  #define padnew_SAVE    2    /* save old globals */
 101  #define padnew_SAVESUB    4    /* also save extra stuff for start of sub */
 102  
 103  /* values for the pad_tidy() function */
 104  
 105  typedef enum {
 106      padtidy_SUB,        /* tidy up a pad for a sub, */
 107      padtidy_SUBCLONE,    /* a cloned sub, */
 108      padtidy_FORMAT        /* or a format */
 109  } padtidy_type;
 110  
 111  /* ASSERT_CURPAD_LEGAL and ASSERT_CURPAD_ACTIVE respectively determine
 112   * whether PL_comppad and PL_curpad are consistent and whether they have
 113   * active values */
 114  
 115  #ifndef PERL_MAD
 116  #  define pad_peg(label)
 117  #endif
 118  
 119  #ifdef DEBUGGING
 120  #  define ASSERT_CURPAD_LEGAL(label) \
 121      pad_peg(label); \
 122      if (PL_comppad ? (AvARRAY(PL_comppad) != PL_curpad) : (PL_curpad != 0))  \
 123      Perl_croak(aTHX_ "panic: illegal pad in %s: 0x%"UVxf"[0x%"UVxf"]",\
 124          label, PTR2UV(PL_comppad), PTR2UV(PL_curpad));
 125  
 126  
 127  #  define ASSERT_CURPAD_ACTIVE(label) \
 128      pad_peg(label); \
 129      if (!PL_comppad || (AvARRAY(PL_comppad) != PL_curpad))          \
 130      Perl_croak(aTHX_ "panic: invalid pad in %s: 0x%"UVxf"[0x%"UVxf"]",\
 131          label, PTR2UV(PL_comppad), PTR2UV(PL_curpad));
 132  #else
 133  #  define ASSERT_CURPAD_LEGAL(label)
 134  #  define ASSERT_CURPAD_ACTIVE(label)
 135  #endif
 136  
 137  
 138  
 139  /* Note: the following three macros are actually defined in scope.h, but
 140   * they are documented here for completeness, since they directly or
 141   * indirectly affect pads.
 142  
 143  =for apidoc m|void|SAVEPADSV    |PADOFFSET po
 144  Save a pad slot (used to restore after an iteration)
 145  
 146  XXX DAPM it would make more sense to make the arg a PADOFFSET
 147  =for apidoc m|void|SAVECLEARSV    |SV **svp
 148  Clear the pointed to pad value on scope exit. (i.e. the runtime action of 'my')
 149  
 150  =for apidoc m|void|SAVECOMPPAD
 151  save PL_comppad and PL_curpad
 152  
 153  
 154  
 155  
 156  
 157  =for apidoc m|SV *|PAD_SETSV    |PADOFFSET po|SV* sv
 158  Set the slot at offset C<po> in the current pad to C<sv>
 159  
 160  =for apidoc m|void|PAD_SV    |PADOFFSET po
 161  Get the value at offset C<po> in the current pad
 162  
 163  =for apidoc m|SV *|PAD_SVl    |PADOFFSET po
 164  Lightweight and lvalue version of C<PAD_SV>.
 165  Get or set the value at offset C<po> in the current pad.
 166  Unlike C<PAD_SV>, does not print diagnostics with -DX.
 167  For internal use only.
 168  
 169  =for apidoc m|SV *|PAD_BASE_SV    |PADLIST padlist|PADOFFSET po
 170  Get the value from slot C<po> in the base (DEPTH=1) pad of a padlist
 171  
 172  =for apidoc m|void|PAD_SET_CUR    |PADLIST padlist|I32 n
 173  Set the current pad to be pad C<n> in the padlist, saving
 174  the previous current pad. NB currently this macro expands to a string too
 175  long for some compilers, so it's best to replace it with
 176  
 177      SAVECOMPPAD();
 178      PAD_SET_CUR_NOSAVE(padlist,n);
 179  
 180  
 181  =for apidoc m|void|PAD_SET_CUR_NOSAVE    |PADLIST padlist|I32 n
 182  like PAD_SET_CUR, but without the save
 183  
 184  =for apidoc m|void|PAD_SAVE_SETNULLPAD
 185  Save the current pad then set it to null.
 186  
 187  =for apidoc m|void|PAD_SAVE_LOCAL|PAD *opad|PAD *npad
 188  Save the current pad to the local variable opad, then make the
 189  current pad equal to npad
 190  
 191  =for apidoc m|void|PAD_RESTORE_LOCAL|PAD *opad
 192  Restore the old pad saved into the local variable opad by PAD_SAVE_LOCAL()
 193  
 194  =cut
 195  */
 196  
 197  #ifdef DEBUGGING
 198  #  define PAD_SV(po)       pad_sv(po)
 199  #  define PAD_SETSV(po,sv) pad_setsv(po,sv)
 200  #else
 201  #  define PAD_SV(po)       (PL_curpad[po])
 202  #  define PAD_SETSV(po,sv) PL_curpad[po] = (sv)
 203  #endif
 204  
 205  #define PAD_SVl(po)       (PL_curpad[po])
 206  
 207  #define PAD_BASE_SV(padlist, po) \
 208      (AvARRAY(padlist)[1])     \
 209          ? AvARRAY((AV*)(AvARRAY(padlist)[1]))[po] : NULL;
 210      
 211  
 212  #define PAD_SET_CUR_NOSAVE(padlist,nth) \
 213      PL_comppad = (PAD*) (AvARRAY(padlist)[nth]);        \
 214      PL_curpad = AvARRAY(PL_comppad);            \
 215      DEBUG_Xv(PerlIO_printf(Perl_debug_log,            \
 216            "Pad 0x%"UVxf"[0x%"UVxf"] set_cur    depth=%d\n",    \
 217            PTR2UV(PL_comppad), PTR2UV(PL_curpad), (int)(nth)));
 218  
 219  
 220  #define PAD_SET_CUR(padlist,nth) \
 221      SAVECOMPPAD();                        \
 222      PAD_SET_CUR_NOSAVE(padlist,nth);
 223  
 224  
 225  #define PAD_SAVE_SETNULLPAD()    SAVECOMPPAD(); \
 226      PL_comppad = NULL; PL_curpad = NULL;    \
 227      DEBUG_Xv(PerlIO_printf(Perl_debug_log, "Pad set_null\n"));
 228  
 229  #define PAD_SAVE_LOCAL(opad,npad) \
 230      opad = PL_comppad;                    \
 231      PL_comppad = (npad);                    \
 232      PL_curpad =  PL_comppad ? AvARRAY(PL_comppad) : NULL;    \
 233      DEBUG_Xv(PerlIO_printf(Perl_debug_log,            \
 234            "Pad 0x%"UVxf"[0x%"UVxf"] save_local\n",        \
 235            PTR2UV(PL_comppad), PTR2UV(PL_curpad)));
 236  
 237  #define PAD_RESTORE_LOCAL(opad) \
 238      PL_comppad = opad;                    \
 239      PL_curpad =  PL_comppad ? AvARRAY(PL_comppad) : NULL;    \
 240      DEBUG_Xv(PerlIO_printf(Perl_debug_log,            \
 241            "Pad 0x%"UVxf"[0x%"UVxf"] restore_local\n",    \
 242            PTR2UV(PL_comppad), PTR2UV(PL_curpad)));
 243  
 244  
 245  /*
 246  =for apidoc m|void|CX_CURPAD_SAVE|struct context
 247  Save the current pad in the given context block structure.
 248  
 249  =for apidoc m|SV *|CX_CURPAD_SV|struct context|PADOFFSET po
 250  Access the SV at offset po in the saved current pad in the given
 251  context block structure (can be used as an lvalue).
 252  
 253  =cut
 254  */
 255  
 256  #define CX_CURPAD_SAVE(block)  (block).oldcomppad = PL_comppad
 257  #define CX_CURPAD_SV(block,po) (AvARRAY((AV*)((block).oldcomppad))[po])
 258  
 259  
 260  /*
 261  =for apidoc m|U32|PAD_COMPNAME_FLAGS|PADOFFSET po
 262  Return the flags for the current compiling pad name
 263  at offset C<po>. Assumes a valid slot entry.
 264  
 265  =for apidoc m|char *|PAD_COMPNAME_PV|PADOFFSET po
 266  Return the name of the current compiling pad name
 267  at offset C<po>. Assumes a valid slot entry.
 268  
 269  =for apidoc m|HV *|PAD_COMPNAME_TYPE|PADOFFSET po
 270  Return the type (stash) of the current compiling pad name at offset
 271  C<po>. Must be a valid name. Returns null if not typed.
 272  
 273  =for apidoc m|HV *|PAD_COMPNAME_OURSTASH|PADOFFSET po
 274  Return the stash associated with an C<our> variable.
 275  Assumes the slot entry is a valid C<our> lexical.
 276  
 277  =for apidoc m|STRLEN|PAD_COMPNAME_GEN|PADOFFSET po
 278  The generation number of the name at offset C<po> in the current
 279  compiling pad (lvalue). Note that C<SvUVX> is hijacked for this purpose.
 280  
 281  =for apidoc m|STRLEN|PAD_COMPNAME_GEN_set|PADOFFSET po|int gen
 282  Sets the generation number of the name at offset C<po> in the current
 283  ling pad (lvalue) to C<gen>.  Note that C<SvUV_set> is hijacked for this purpose.
 284  
 285  =cut
 286  
 287  */
 288  
 289  #define PAD_COMPNAME_SV(po) (*av_fetch(PL_comppad_name, (po), FALSE))
 290  #define PAD_COMPNAME_FLAGS(po) SvFLAGS(PAD_COMPNAME_SV(po))
 291  #define PAD_COMPNAME_FLAGS_isOUR(po) \
 292    ((PAD_COMPNAME_FLAGS(po) & (SVpad_NAME|SVpad_OUR)) == (SVpad_NAME|SVpad_OUR))
 293  #define PAD_COMPNAME_PV(po) SvPV_nolen(PAD_COMPNAME_SV(po))
 294  
 295  #define PAD_COMPNAME_TYPE(po) pad_compname_type(po)
 296  
 297  #define PAD_COMPNAME_OURSTASH(po) \
 298      (SvOURSTASH(PAD_COMPNAME_SV(po)))
 299  
 300  #define PAD_COMPNAME_GEN(po) ((STRLEN)SvUVX(AvARRAY(PL_comppad_name)[po]))
 301  
 302  #define PAD_COMPNAME_GEN_set(po, gen) SvUV_set(AvARRAY(PL_comppad_name)[po], (UV)(gen))
 303  
 304  
 305  /*
 306  =for apidoc m|void|PAD_DUP|PADLIST dstpad|PADLIST srcpad|CLONE_PARAMS* param
 307  Clone a padlist.
 308  
 309  =for apidoc m|void|PAD_CLONE_VARS|PerlInterpreter *proto_perl \
 310  |CLONE_PARAMS* param
 311  Clone the state variables associated with running and compiling pads.
 312  
 313  =cut
 314  */
 315  
 316  
 317  #define PAD_DUP(dstpad, srcpad, param)                \
 318      if ((srcpad) && !AvREAL(srcpad)) {                \
 319      /* XXX padlists are real, but pretend to be not */     \
 320      AvREAL_on(srcpad);                    \
 321      (dstpad) = av_dup_inc((srcpad), param);            \
 322      AvREAL_off(srcpad);                    \
 323      AvREAL_off(dstpad);                    \
 324      }                                \
 325      else                            \
 326      (dstpad) = av_dup_inc((srcpad), param);            
 327  
 328  /* NB - we set PL_comppad to null unless it points at a value that
 329   * has already been dup'ed, ie it points to part of an active padlist.
 330   * Otherwise PL_comppad ends up being a leaked scalar in code like
 331   * the following:
 332   *     threads->create(sub { threads->create(sub {...} ) } );
 333   * where the second thread dups the outer sub's comppad but not the
 334   * sub's CV or padlist. */
 335  
 336  #define PAD_CLONE_VARS(proto_perl, param)                \
 337      PL_comppad = (AV *) ptr_table_fetch(PL_ptr_table, proto_perl->Icomppad); \
 338      PL_curpad = PL_comppad ?  AvARRAY(PL_comppad) : NULL;        \
 339      PL_comppad_name        = av_dup(proto_perl->Icomppad_name, param); \
 340      PL_comppad_name_fill    = proto_perl->Icomppad_name_fill;    \
 341      PL_comppad_name_floor    = proto_perl->Icomppad_name_floor;    \
 342      PL_min_intro_pending    = proto_perl->Imin_intro_pending;    \
 343      PL_max_intro_pending    = proto_perl->Imax_intro_pending;    \
 344      PL_padix            = proto_perl->Ipadix;            \
 345      PL_padix_floor        = proto_perl->Ipadix_floor;        \
 346      PL_pad_reset_pending    = proto_perl->Ipad_reset_pending;    \
 347      PL_cop_seqmax        = proto_perl->Icop_seqmax;