opcode.h

opcode.h contains information about each operation. In Perl language research, "OP type" data is called an operation. Perl is converted to a syntax tree after parsing, but each of these nodes is "OP type".

Operations are categorized by operation code, and each has its own information. That information is described.

Name of operation

For example, the name of the operation is described.

EXTCONST char * const PL_op_name [] = {
  "null",
  "stub",
  "scalar",
  "pushmark",
  "wantarray",
  "const",
  "gvsv",
  ...
};

=====

Operation explanation

Next, a description of the operation is described.

EXTCONST char * const PL_op_desc [] = {
  "null operation",
  "stub",
  "scalar",
  "pushmark",
  "wantarray",
  "constant item",
  "a scalar variable",
  "glob value",
  ...
};

Address of the function that the operation executes

Each operation has a corresponding function, but the address to that function is described.

EXT Perl_ppaddr_t PL_ppaddr [] /* or perlvars.h */# endif
# endif/* PERL_GLOBAL_STRUCT */# if (defined(DOINIT) &&! Defined (PERL_GLOBAL_STRUCT)) || defined(PERL_GLOBAL_STRUCT_INIT)
# define PERL_PPADDR_INITED
= {
  Perl_pp_null,
  Perl_pp_stub,
  Perl_pp_scalar,/* implemented by Perl_pp_null */  Perl_pp_pushmark,
  Perl_pp_wantarray,
  Perl_pp_const,
  Perl_pp_gvsv,
  Perl_pp_gv,
  ...
}

The prefix "pp" means "push pop", and the function executed is the function that manipulates the argument stack.

Functions that optimize operations

Each operation is optimized with a function prefixed with "ck". The address of the function is described. "Ck" is an abbreviation for "check".

# if (defined(DOINIT) &&! Defined (PERL_GLOBAL_STRUCT)) || defined(PERL_GLOBAL_STRUCT_INIT)
# define PERL_CHECK_INITED
= {
  Perl_ck_null,/* null */  Perl_ck_null,/* stub */  Perl_ck_fun,/* scalar */  Perl_ck_null,/* pushmark */  Perl_ck_null,/* wantarray */  Perl_ck_svconst,/* const */  Perl_ck_null,/* gvsv */};

Function argument information

The argument information of the function to be executed is described.

EXTCONST U32 PL_opargs [] = {
  0x00000000,/* null */  0x00000000,/* stub */  0x00001b04,/* scalar */  0x00000004,/* pushmark */  0x00000004,/* wantarray */  0x00000604,/* const */  0x00000644,/* gvsv */  0x00000644,/* gv */  ...
};

This is written numerically and I don't know what it is. It is defined in "op.h". The above value is the value of the logical sum of the bit operations of the following values.

/* op.h */
/ * Lowest byte of PL_opargs */# define OA_MARK 1
# define OA_FOLDCONST 2
# define OA_RETSCALAR 4
# define OA_TARGET 8
# define OA_TARGLEX 16
# define OA_OTHERINT 32
# define OA_DANGEROUS 64
# define OA_DEFGV 128

/ * The next 4 bits (8..11) encode op class information */# define OCSHIFT 8

# define OA_CLASS_MASK (15 << OCSHIFT)

# define OA_BASEOP (0 << OCSHIFT)
# define OA_UNOP (1 << OCSHIFT)
# define OA_BINOP (2 << OCSHIFT)
# define OA_LOGOP (3 << OCSHIFT)
# define OA_LISTOP (4 << OCSHIFT)
# define OA_PMOP (5 << OCSHIFT)
# define OA_SVOP (6 << OCSHIFT)
# define OA_PADOP (7 << OCSHIFT)
# define OA_PVOP_OR_SVOP (8 << OCSHIFT)
# define OA_LOOP (9 << OCSHIFT)
# define OA_COP (10 << OCSHIFT)
# define OA_BASEOP_OR_UNOP (11 << OCSHIFT)
# define OA_FILESTATOP (12 << OCSHIFT)
# define OA_LOOPEXOP (13 << OCSHIFT)
# define OA_METHOP (14 << OCSHIFT)
# define OA_UNOP_AUX (15 << OCSHIFT)

/ * Each remaining nybble of PL_opargs (i.e. bits 12..15, 16..19 etc)
 * encode the type for each arg */# define OASHIFT 12

# define OA_SCALAR 1
# define OA_LIST 2
# define OA_AVREF 3
# define OA_HVREF 4
# define OA_CVREF 5
# define OA_FILEREF 6
# define OA_SCALARREF 7
# define OA_OPTIONAL 8

And the above doesn't explain this value, but it's in "regen/opcodes".

# Other options are:
# needs stack mark - m (OA_MARK)
# needs constant folding - f (OA_FOLDCONST)
# produces a scalar - s (OA_RETSCALAR)
# produces an integer - i (unused)
# needs a target - t (OA_TARGET)
# target can be in a pad - T (OA_TARGET | OA_TARGLEX)
# has a corresponding integer version - I (OA_OTHERINT)
# make temp copy in list assignment - d (OA_DANGEROUS)
# uses $_ if no argument given - u (OA_DEFGV)

Private flags for operations

And there is private flag information about the operation. A detailed description of these can be found in "regen/op_private".

# define OPpLVREF_SV 0x00
# define OPpARG1_MASK 0x01
# define OPpCOREARGS_DEREF1 0x01
# define OPpENTERSUB_INARGS 0x01
# define OPpSORT_NUMERIC 0x01
# define OPpTRANS_FROM_UTF 0x01
# define OPpCONST_NOVER 0x02
# define OPpCOREARGS_DEREF2 0x02
# define OPpEVAL_HAS_HH 0x02
# define OPpFT_ACCESS 0x02
# define OPpHINT_STRICT_REFS 0x02
# define OPpITER_REVERSED 0x02
...

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