/* Compile an expression node to intermediate code */

/* XXX TO DO:

XXX add __doc__ attribute == co_doc to code object attributes?

XXX (it's currently the first item of the co_const tuple)

XXX Generate simple jump for break/return outside 'try...finally'

XXX Allow 'continue' inside finally clause of try-finally

XXX New opcode for loading the initial index for a for loop

XXX other JAR tricks?

*/

#include "Python.h"

#include "node.h"

#include "token.h"

#include "graminit.h"

#include "compile.h"

#include "symtable.h"

#include "opcode.h"

#include "structmember.h"

#include <ctype.h>

/* Three symbols from graminit.h are also defined in Python.h, with

Py_ prefixes to their names. Python.h can't include graminit.h

(which defines too many confusing symbols), but we can check here

that they haven't changed (which is very unlikely, but possible). */

#if Py_single_input != single_input

#error "single_input has changed -- update Py_single_input in Python.h"

#endif

#if Py_file_input != file_input

#error "file_input has changed -- update Py_file_input in Python.h"

#endif

#if Py_eval_input != eval_input

#error "eval_input has changed -- update Py_eval_input in Python.h"

#endif

int Py_OptimizeFlag = 0;

#define OP_DELETE 0

#define OP_ASSIGN 1

#define OP_APPLY 2

#define VAR_LOAD 0

#define VAR_STORE 1

#define VAR_DELETE 2

#define DEL_CLOSURE_ERROR \

"can not delete variable '%.400s' referenced in nested scope"

#define DUPLICATE_ARGUMENT \

"duplicate argument '%s' in function definition"

#define ILLEGAL_DYNAMIC_SCOPE \

"%.100s: exec or 'import *' makes names ambiguous in nested scope"

#define GLOBAL_AFTER_ASSIGN \

"name '%.400s' is assigned to before global declaration"

#define GLOBAL_AFTER_USE \

"name '%.400s' is used prior to global declaration"

#define LOCAL_GLOBAL \

"name '%.400s' is a function paramter and declared global"

#define LATE_FUTURE \

"from __future__ imports must occur at the beginning of the file"

#define ASSIGN_DEBUG \

"can not assign to __debug__"

#define MANGLE_LEN 256

#define OFF(x) offsetof(PyCodeObject, x)

static struct memberlist code_memberlist[] = {

{"co_argcount", T_INT, OFF(co_argcount), READONLY},

{"co_nlocals", T_INT, OFF(co_nlocals), READONLY},

{"co_stacksize",T_INT, OFF(co_stacksize), READONLY},

{"co_flags", T_INT, OFF(co_flags), READONLY},

{"co_code", T_OBJECT, OFF(co_code), READONLY},

{"co_consts", T_OBJECT, OFF(co_consts), READONLY},

{"co_names", T_OBJECT, OFF(co_names), READONLY},

{"co_varnames", T_OBJECT, OFF(co_varnames), READONLY},

{"co_freevars", T_OBJECT, OFF(co_freevars), READONLY},

{"co_cellvars", T_OBJECT, OFF(co_cellvars), READONLY},

{"co_filename", T_OBJECT, OFF(co_filename), READONLY},

{"co_name", T_OBJECT, OFF(co_name), READONLY},

{"co_firstlineno", T_INT, OFF(co_firstlineno), READONLY},

{"co_lnotab", T_OBJECT, OFF(co_lnotab), READONLY},

{NULL} /* Sentinel */

};

static PyObject *

code_getattr(PyCodeObject *co, char *name)

{

return PyMember_Get((char *)co, code_memberlist, name);

}

static void

code_dealloc(PyCodeObject *co)

{

Py_XDECREF(co->co_code);

Py_XDECREF(co->co_consts);

Py_XDECREF(co->co_names);

Py_XDECREF(co->co_varnames);

Py_XDECREF(co->co_freevars);

Py_XDECREF(co->co_cellvars);

Py_XDECREF(co->co_filename);

Py_XDECREF(co->co_name);

Py_XDECREF(co->co_lnotab);

PyObject_DEL(co);

}

static PyObject *

code_repr(PyCodeObject *co)

{

char buf[500];

int lineno = -1;

char *filename = "???";

char *name = "???";

if (co->co_firstlineno != 0)

lineno = co->co_firstlineno;

if (co->co_filename && PyString_Check(co->co_filename))

filename = PyString_AS_STRING(co->co_filename);

if (co->co_name && PyString_Check(co->co_name))

name = PyString_AS_STRING(co->co_name);

sprintf(buf, "<code object %.100s at %p, file \"%.300s\", line %d>",

name, co, filename, lineno);

return PyString_FromString(buf);

}

static int

code_compare(PyCodeObject *co, PyCodeObject *cp)

{

int cmp;

cmp = PyObject_Compare(co->co_name, cp->co_name);

if (cmp) return cmp;

cmp = co->co_argcount - cp->co_argcount;

if (cmp) return cmp;

cmp = co->co_nlocals - cp->co_nlocals;

if (cmp) return cmp;

cmp = co->co_flags - cp->co_flags;

if (cmp) return cmp;

cmp = PyObject_Compare(co->co_code, cp->co_code);

if (cmp) return cmp;

cmp = PyObject_Compare(co->co_consts, cp->co_consts);

if (cmp) return cmp;

cmp = PyObject_Compare(co->co_names, cp->co_names);

if (cmp) return cmp;

cmp = PyObject_Compare(co->co_varnames, cp->co_varnames);

if (cmp) return cmp;

cmp = PyObject_Compare(co->co_freevars, cp->co_freevars);

if (cmp) return cmp;

cmp = PyObject_Compare(co->co_cellvars, cp->co_cellvars);

return cmp;

}

static long

code_hash(PyCodeObject *co)

{

long h, h0, h1, h2, h3, h4, h5, h6;

h0 = PyObject_Hash(co->co_name);

if (h0 == -1) return -1;

h1 = PyObject_Hash(co->co_code);

if (h1 == -1) return -1;

h2 = PyObject_Hash(co->co_consts);

if (h2 == -1) return -1;

h3 = PyObject_Hash(co->co_names);

if (h3 == -1) return -1;

h4 = PyObject_Hash(co->co_varnames);

if (h4 == -1) return -1;

h5 = PyObject_Hash(co->co_freevars);

if (h5 == -1) return -1;

h6 = PyObject_Hash(co->co_cellvars);

if (h6 == -1) return -1;

h = h0 ^ h1 ^ h2 ^ h3 ^ h4 ^ h5 ^ h6 ^

co->co_argcount ^ co->co_nlocals ^ co->co_flags;

if (h == -1) h = -2;

return h;

}

/* XXX code objects need to participate in GC? */

PyTypeObject PyCode_Type = {

PyObject_HEAD_INIT(&PyType_Type)

0,

"code",

sizeof(PyCodeObject),

0,

(destructor)code_dealloc, /*tp_dealloc*/

0, /*tp_print*/

(getattrfunc)code_getattr, /*tp_getattr*/

0, /*tp_setattr*/

(cmpfunc)code_compare, /*tp_compare*/

(reprfunc)code_repr, /*tp_repr*/

0, /*tp_as_number*/

0, /*tp_as_sequence*/

0, /*tp_as_mapping*/

(hashfunc)code_hash, /*tp_hash*/

};

#define NAME_CHARS \

"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz"

/* all_name_chars(s): true iff all chars in s are valid NAME_CHARS */

static int

all_name_chars(unsigned char *s)

{

static char ok_name_char[256];

static unsigned char *name_chars = (unsigned char *)NAME_CHARS;

if (ok_name_char[*name_chars] == 0) {

unsigned char *p;

for (p = name_chars; *p; p++)

ok_name_char[*p] = 1;

}

while (*s) {

if (ok_name_char[*s++] == 0)

return 0;

}

return 1;

}

static int

intern_strings(PyObject *tuple)

{

int i;

for (i = PyTuple_GET_SIZE(tuple); --i >= 0; ) {

PyObject *v = PyTuple_GET_ITEM(tuple, i);

if (v == NULL || !PyString_Check(v)) {

Py_FatalError("non-string found in code slot");

PyErr_BadInternalCall();

return -1;

}

PyString_InternInPlace(&PyTuple_GET_ITEM(tuple, i));

}

return 0;

}

PyCodeObject *

PyCode_New(int argcount, int nlocals, int stacksize, int flags,

PyObject *code, PyObject *consts, PyObject *names,

PyObject *varnames, PyObject *freevars, PyObject *cellvars,

PyObject *filename, PyObject *name, int firstlineno,

PyObject *lnotab)

{

PyCodeObject *co;

int i;

PyBufferProcs *pb;

/* Check argument types */

if (argcount < 0 || nlocals < 0 ||

code == NULL ||

consts == NULL || !PyTuple_Check(consts) ||

names == NULL || !PyTuple_Check(names) ||

varnames == NULL || !PyTuple_Check(varnames) ||

freevars == NULL || !PyTuple_Check(freevars) ||

cellvars == NULL || !PyTuple_Check(cellvars) ||

name == NULL || !PyString_Check(name) ||

filename == NULL || !PyString_Check(filename) ||

lnotab == NULL || !PyString_Check(lnotab)) {

PyErr_BadInternalCall();

return NULL;

}

pb = code->ob_type->tp_as_buffer;

if (pb == NULL ||

pb->bf_getreadbuffer == NULL ||

pb->bf_getsegcount == NULL ||

(*pb->bf_getsegcount)(code, NULL) != 1)

{

PyErr_BadInternalCall();

return NULL;

}

intern_strings(names);

intern_strings(varnames);

if (freevars == NULL)

freevars = PyTuple_New(0);

intern_strings(freevars);

if (cellvars == NULL)

cellvars = PyTuple_New(0);

intern_strings(cellvars);

/* Intern selected string constants */

for (i = PyTuple_Size(consts); --i >= 0; ) {

PyObject *v = PyTuple_GetItem(consts, i);

if (!PyString_Check(v))

continue;

if (!all_name_chars((unsigned char *)PyString_AS_STRING(v)))

continue;

PyString_InternInPlace(&PyTuple_GET_ITEM(consts, i));

}

co = PyObject_NEW(PyCodeObject, &PyCode_Type);

if (co != NULL) {

co->co_argcount = argcount;

co->co_nlocals = nlocals;

co->co_stacksize = stacksize;

co->co_flags = flags;

Py_INCREF(code);

co->co_code = code;

Py_INCREF(consts);

co->co_consts = consts;

Py_INCREF(names);

co->co_names = names;

Py_INCREF(varnames);

co->co_varnames = varnames;

Py_INCREF(freevars);

co->co_freevars = freevars;

Py_INCREF(cellvars);

co->co_cellvars = cellvars;

Py_INCREF(filename);

co->co_filename = filename;

Py_INCREF(name);

co->co_name = name;

co->co_firstlineno = firstlineno;

Py_INCREF(lnotab);

co->co_lnotab = lnotab;

}

return co;

}

/* Data structure used internally */

/* The compiler uses two passes to generate bytecodes. The first pass

builds the symbol table. The second pass generates the bytecode.

The first pass uses a single symtable struct. The second pass uses

a compiling struct for each code block. The compiling structs

share a reference to the symtable.

The two passes communicate via symtable_load_symbols() and via

is_local() and is_global(). The former initializes several slots

in the compiling struct: c_varnames, c_locals, c_nlocals,

c_argcount, c_globals, and c_flags.

*/

/* All about c_lnotab.

c_lnotab is an array of unsigned bytes disguised as a Python string. In -O

mode, SET_LINENO opcodes aren't generated, and bytecode offsets are mapped

to source code line #s (when needed for tracebacks) via c_lnotab instead.

The array is conceptually a list of

(bytecode offset increment, line number increment)

pairs. The details are important and delicate, best illustrated by example:

byte code offset source code line number

0 1

6 2

50 7

350 307

361 308

The first trick is that these numbers aren't stored, only the increments

from one row to the next (this doesn't really work, but it's a start):

0, 1, 6, 1, 44, 5, 300, 300, 11, 1

The second trick is that an unsigned byte can't hold negative values, or

values larger than 255, so (a) there's a deep assumption that byte code

offsets and their corresponding line #s both increase monotonically, and (b)

if at least one column jumps by more than 255 from one row to the next, more

than one pair is written to the table. In case #b, there's no way to know

from looking at the table later how many were written. That's the delicate

part. A user of c_lnotab desiring to find the source line number

corresponding to a bytecode address A should do something like this

lineno = addr = 0

for addr_incr, line_incr in c_lnotab:

addr += addr_incr

if addr > A:

return lineno

lineno += line_incr

In order for this to work, when the addr field increments by more than 255,

the line # increment in each pair generated must be 0 until the remaining addr

increment is < 256. So, in the example above, com_set_lineno should not (as

was actually done until 2.2) expand 300, 300 to 255, 255, 45, 45, but to

255, 0, 45, 255, 0, 45.

*/

struct compiling {

PyObject *c_code; /* string */

PyObject *c_consts; /* list of objects */

PyObject *c_const_dict; /* inverse of c_consts */

PyObject *c_names; /* list of strings (names) */

PyObject *c_name_dict; /* inverse of c_names */

PyObject *c_globals; /* dictionary (value=None) */

PyObject *c_locals; /* dictionary (value=localID) */

PyObject *c_varnames; /* list (inverse of c_locals) */

PyObject *c_freevars; /* dictionary (value=None) */

PyObject *c_cellvars; /* list */

int c_nlocals; /* index of next local */

int c_argcount; /* number of top-level arguments */

int c_flags; /* same as co_flags */

int c_nexti; /* index into c_code */

int c_errors; /* counts errors occurred */

int c_infunction; /* set when compiling a function */

int c_interactive; /* generating code for interactive command */

int c_loops; /* counts nested loops */

int c_begin; /* begin of current loop, for 'continue' */

int c_block[CO_MAXBLOCKS]; /* stack of block types */

int c_nblocks; /* current block stack level */

char *c_filename; /* filename of current node */

char *c_name; /* name of object (e.g. function) */

int c_lineno; /* Current line number */

int c_stacklevel; /* Current stack level */

int c_maxstacklevel; /* Maximum stack level */

int c_firstlineno;

PyObject *c_lnotab; /* Table mapping address to line number */

int c_last_addr, c_last_line, c_lnotab_next;

char *c_private; /* for private name mangling */

int c_tmpname; /* temporary local name counter */

int c_nested; /* Is block nested funcdef or lamdef? */

int c_closure; /* Is nested w/freevars? */

struct symtable *c_symtable; /* pointer to module symbol table */

PyFutureFeatures *c_future; /* pointer to module's __future__ */

};

static int

is_free(int v)

{

if ((v & (USE | DEF_FREE))

&& !(v & (DEF_LOCAL | DEF_PARAM | DEF_GLOBAL)))

return 1;

if (v & DEF_FREE_CLASS)

return 1;

return 0;

}

static void

com_error(struct compiling *c, PyObject *exc, char *msg)

{

PyObject *t = NULL, *v = NULL, *w = NULL, *line = NULL;

if (c == NULL) {

/* Error occurred via symtable call to

is_constant_false */

PyErr_SetString(exc, msg);

return;

}

c->c_errors++;

if (c->c_lineno < 1 || c->c_interactive) {

/* Unknown line number or interactive input */

PyErr_SetString(exc, msg);

return;

}

v = PyString_FromString(msg);

if (v == NULL)

return; /* MemoryError, too bad */

line = PyErr_ProgramText(c->c_filename, c->c_lineno);

if (line == NULL) {

Py_INCREF(Py_None);

line = Py_None;

}

t = Py_BuildValue("(ziOO)", c->c_filename, c->c_lineno,

Py_None, line);

if (t == NULL)

goto exit;

w = Py_BuildValue("(OO)", v, t);

if (w == NULL)

goto exit;

PyErr_SetObject(exc, w);

exit:

Py_XDECREF(t);

Py_XDECREF(v);

Py_XDECREF(w);

Py_XDECREF(line);

}

/* Interface to the block stack */

static void

block_push(struct compiling *c, int type)

{

if (c->c_nblocks >= CO_MAXBLOCKS) {

com_error(c, PyExc_SystemError,

"too many statically nested blocks");

}

else {

c->c_block[c->c_nblocks++] = type;

}

}

static void

block_pop(struct compiling *c, int type)

{

if (c->c_nblocks > 0)

c->c_nblocks--;

if (c->c_block[c->c_nblocks] != type && c->c_errors == 0) {

com_error(c, PyExc_SystemError, "bad block pop");

}

}

/* Prototype forward declarations */

static int com_init(struct compiling *, char *);

static void com_free(struct compiling *);

static void com_push(struct compiling *, int);

static void com_pop(struct compiling *, int);

static void com_done(struct compiling *);

static void com_node(struct compiling *, node *);

static void com_factor(struct compiling *, node *);

static void com_addbyte(struct compiling *, int);

static void com_addint(struct compiling *, int);

static void com_addoparg(struct compiling *, int, int);

static void com_addfwref(struct compiling *, int, int *);

static void com_backpatch(struct compiling *, int);

static int com_add(struct compiling *, PyObject *, PyObject *, PyObject *);

static int com_addconst(struct compiling *, PyObject *);

static int com_addname(struct compiling *, PyObject *);

static void com_addopname(struct compiling *, int, node *);

static void com_list(struct compiling *, node *, int);

static void com_list_iter(struct compiling *, node *, node *, char *);

static int com_argdefs(struct compiling *, node *);

static void com_assign(struct compiling *, node *, int, node *);

static void com_assign_name(struct compiling *, node *, int);

static PyCodeObject *icompile(node *, struct compiling *);

static PyCodeObject *jcompile(node *, char *, struct compiling *,

PyCompilerFlags *);

static PyObject *parsestrplus(struct compiling*, node *);

static PyObject *parsestr(struct compiling *, char *);

static node *get_rawdocstring(node *);

static int get_ref_type(struct compiling *, char *);

/* symtable operations */

static int symtable_build(struct compiling *, node *);

static int symtable_load_symbols(struct compiling *);

static struct symtable *symtable_init(void);

static void symtable_enter_scope(struct symtable *, char *, int, int);

static int symtable_exit_scope(struct symtable *);

static int symtable_add_def(struct symtable *, char *, int);

static int symtable_add_def_o(struct symtable *, PyObject *, PyObject *, int);

static void symtable_node(struct symtable *, node *);

static void symtable_funcdef(struct symtable *, node *);

static void symtable_default_args(struct symtable *, node *);

static void symtable_params(struct symtable *, node *);

static void symtable_params_fplist(struct symtable *, node *n);

static void symtable_global(struct symtable *, node *);

static void symtable_import(struct symtable *, node *);

static void symtable_assign(struct symtable *, node *, int);

static void symtable_list_comprehension(struct symtable *, node *);

static int symtable_update_free_vars(struct symtable *);

static int symtable_undo_free(struct symtable *, PyObject *, PyObject *);

static int symtable_check_global(struct symtable *, PyObject *, PyObject *);

/* helper */

static void

do_pad(int pad)

{

int i;

for (i = 0; i < pad; ++i)

fprintf(stderr, " ");

}

static void

dump(node *n, int pad, int depth)

{

int i;

if (depth == 0)

return;

do_pad(pad);

fprintf(stderr, "%d: %s\n", TYPE(n), STR(n));

if (depth > 0)

depth--;

for (i = 0; i < NCH(n); ++i)

dump(CHILD(n, i), pad + 1, depth);

}

#define DUMP(N) dump(N, 0, -1)

static int

com_init(struct compiling *c, char *filename)

{

memset((void *)c, '\0', sizeof(struct compiling));

if ((c->c_code = PyString_FromStringAndSize((char *)NULL,

1000)) == NULL)

goto fail;

if ((c->c_consts = PyList_New(0)) == NULL)

goto fail;

if ((c->c_const_dict = PyDict_New()) == NULL)

goto fail;

if ((c->c_names = PyList_New(0)) == NULL)

goto fail;

if ((c->c_name_dict = PyDict_New()) == NULL)

goto fail;

if ((c->c_locals = PyDict_New()) == NULL)

goto fail;

if ((c->c_lnotab = PyString_FromStringAndSize((char *)NULL,

1000)) == NULL)

goto fail;

c->c_globals = NULL;

c->c_varnames = NULL;

c->c_freevars = NULL;

c->c_cellvars = NULL;

c->c_nlocals = 0;

c->c_argcount = 0;

c->c_flags = 0;

c->c_nexti = 0;

c->c_errors = 0;

c->c_infunction = 0;

c->c_interactive = 0;

c->c_loops = 0;

c->c_begin = 0;

c->c_nblocks = 0;

c->c_filename = filename;

c->c_name = "?";

c->c_lineno = 0;

c->c_stacklevel = 0;

c->c_maxstacklevel = 0;

c->c_firstlineno = 0;

c->c_last_addr = 0;

c->c_last_line = 0;

c->c_lnotab_next = 0;

c->c_tmpname = 0;

c->c_nested = 0;

c->c_closure = 0;

c->c_symtable = NULL;

return 1;

fail:

com_free(c);

return 0;

}

static void

com_free(struct compiling *c)

{

Py_XDECREF(c->c_code);

Py_XDECREF(c->c_consts);

Py_XDECREF(c->c_const_dict);

Py_XDECREF(c->c_names);

Py_XDECREF(c->c_name_dict);

Py_XDECREF(c->c_globals);

Py_XDECREF(c->c_locals);

Py_XDECREF(c->c_varnames);

Py_XDECREF(c->c_freevars);

Py_XDECREF(c->c_cellvars);

Py_XDECREF(c->c_lnotab);

if (c->c_future)

PyMem_Free((void *)c->c_future);

}

static void

com_push(struct compiling *c, int n)

{

c->c_stacklevel += n;

if (c->c_stacklevel > c->c_maxstacklevel)

c->c_maxstacklevel = c->c_stacklevel;

}

static void

com_pop(struct compiling *c, int n)

{

if (c->c_stacklevel < n) {

/* fprintf(stderr,

"%s:%d: underflow! nexti=%d, level=%d, n=%d\n",

c->c_filename, c->c_lineno,

c->c_nexti, c->c_stacklevel, n); */

c->c_stacklevel = 0;

}

else

c->c_stacklevel -= n;

}

static void

com_done(struct compiling *c)

{

if (c->c_code != NULL)

_PyString_Resize(&c->c_code, c->c_nexti);

if (c->c_lnotab != NULL)

_PyString_Resize(&c->c_lnotab, c->c_lnotab_next);

}

static void

com_addbyte(struct compiling *c, int byte)

{

int len;

/*fprintf(stderr, "%3d: %3d\n", c->c_nexti, byte);*/

assert(byte >= 0 && byte <= 255);

if (byte < 0 || byte > 255) {

com_error(c, PyExc_SystemError,

"com_addbyte: byte out of range");

}

if (c->c_code == NULL)

return;

len = PyString_Size(c->c_code);

if (c->c_nexti >= len) {

if (_PyString_Resize(&c->c_code, len+1000) != 0) {

c->c_errors++;

return;

}

}

PyString_AsString(c->c_code)[c->c_nexti++] = byte;

}

static void

com_addint(struct compiling *c, int x)

{

com_addbyte(c, x & 0xff);

com_addbyte(c, x >> 8); /* XXX x should be positive */

}

static void

com_add_lnotab(struct compiling *c, int addr, int line)

{

int size;

char *p;

if (c->c_lnotab == NULL)

return;

size = PyString_Size(c->c_lnotab);

if (c->c_lnotab_next+2 > size) {

if (_PyString_Resize(&c->c_lnotab, size + 1000) < 0) {

c->c_errors++;

return;

}

}

p = PyString_AsString(c->c_lnotab) + c->c_lnotab_next;

*p++ = addr;

*p++ = line;

c->c_lnotab_next += 2;

}

static void

com_set_lineno(struct compiling *c, int lineno)

{

c->c_lineno = lineno;

if (c->c_firstlineno == 0) {

c->c_firstlineno = c->c_last_line = lineno;

}

else {

int incr_addr = c->c_nexti - c->c_last_addr;

int incr_line = lineno - c->c_last_line;

while (incr_addr > 255) {

com_add_lnotab(c, 255, 0);

incr_addr -= 255;

}

while (incr_line > 255) {

com_add_lnotab(c, incr_addr, 255);

incr_line -=255;

incr_addr = 0;

}

if (incr_addr > 0 || incr_line > 0)

com_add_lnotab(c, incr_addr, incr_line);

c->c_last_addr = c->c_nexti;

c->c_last_line = lineno;

}

}

static void

com_addoparg(struct compiling *c, int op, int arg)

{

int extended_arg = arg >> 16;

if (op == SET_LINENO) {

com_set_lineno(c, arg);

if (Py_OptimizeFlag)

return;

}

if (extended_arg){

com_addbyte(c, EXTENDED_ARG);

com_addint(c, extended_arg);

arg &= 0xffff;

}

com_addbyte(c, op);

com_addint(c, arg);

}

static void

com_addfwref(struct compiling *c, int op, int *p_anchor)

{

/* Compile a forward reference for backpatching */

int here;

int anchor;

com_addbyte(c, op);

here = c->c_nexti;

anchor = *p_anchor;

*p_anchor = here;

com_addint(c, anchor == 0 ? 0 : here - anchor);

}

static void

com_backpatch(struct compiling *c, int anchor)

{

unsigned char *code = (unsigned char *) PyString_AsString(c->c_code);

int target = c->c_nexti;

int dist;

int prev;

for (;;) {

/* Make the JUMP instruction at anchor point to target */

prev = code[anchor] + (code[anchor+1] << 8);

dist = target - (anchor+2);

code[anchor] = dist & 0xff;

dist >>= 8;

code[anchor+1] = dist;

dist >>= 8;

if (dist) {

com_error(c, PyExc_SystemError,

"com_backpatch: offset too large");

break;

}

if (!prev)

break;

anchor -= prev;

}

}

/* Handle literals and names uniformly */

static int

com_add(struct compiling *c, PyObject *list, PyObject *dict, PyObject *v)

{

PyObject *w, *t, *np=NULL;

long n;

t = Py_BuildValue("(OO)", v, v->ob_type);

if (t == NULL)

goto fail;

w = PyDict_GetItem(dict, t);

if (w != NULL) {

n = PyInt_AsLong(w);

} else {

n = PyList_Size(list);

np = PyInt_FromLong(n);

if (np == NULL)

goto fail;

if (PyList_Append(list, v) != 0)

goto fail;

if (PyDict_SetItem(dict, t, np) != 0)

goto fail;

Py_DECREF(np);

}

Py_DECREF(t);

return n;

fail:

Py_XDECREF(np);

Py_XDECREF(t);

c->c_errors++;

return 0;

}

static int

com_addconst(struct compiling *c, PyObject *v)

{

return com_add(c, c->c_consts, c->c_const_dict, v);

}

static int

com_addname(struct compiling *c, PyObject *v)

{

return com_add(c, c->c_names, c->c_name_dict, v);

}

static int

mangle(char *p, char *name, char *buffer, size_t maxlen)

{

/* Name mangling: __private becomes _classname__private.

This is independent from how the name is used. */

size_t nlen, plen;

if (p == NULL || name == NULL || name[0] != '_' || name[1] != '_')

return 0;

nlen = strlen(name);

if (nlen+2 >= maxlen)

return 0; /* Don't mangle __extremely_long_names */

if (name[nlen-1] == '_' && name[nlen-2] == '_')

return 0; /* Don't mangle __whatever__ */

/* Strip leading underscores from class name */

while (*p == '_')

p++;

if (*p == '\0')

return 0; /* Don't mangle if class is just underscores */

plen = strlen(p);

if (plen + nlen >= maxlen)

plen = maxlen-nlen-2; /* Truncate class name if too long */

/* buffer = "_" + p[:plen] + name # i.e. 1+plen+nlen bytes */

buffer[0] = '_';

strncpy(buffer+1, p, plen);

strcpy(buffer+1+plen, name);

return 1;

}

static void

com_addop_name(struct compiling *c, int op, char *name)

{

PyObject *v;

int i;

char buffer[MANGLE_LEN];

if (mangle(c->c_private, name, buffer, sizeof(buffer)))

name = buffer;

if (name == NULL || (v = PyString_InternFromString(name)) == NULL) {

c->c_errors++;

i = 255;

}

else {

i = com_addname(c, v);

Py_DECREF(v);

}

com_addoparg(c, op, i);

}

#define NAME_LOCAL 0

#define NAME_GLOBAL 1

#define NAME_DEFAULT 2

#define NAME_CLOSURE 3

static int

com_lookup_arg(PyObject *dict, PyObject *name)

{

PyObject *v = PyDict_GetItem(dict, name);

if (v == NULL)

return -1;

else

return PyInt_AS_LONG(v);

}

static void

com_addop_varname(struct compiling *c, int kind, char *name)

{

PyObject *v;

int i, reftype;

int scope = NAME_DEFAULT;

int op = STOP_CODE;

char buffer[MANGLE_LEN];

if (mangle(c->c_private, name, buffer, sizeof(buffer)))

name = buffer;

if (name == NULL || (v = PyString_InternFromString(name)) == NULL) {

c->c_errors++;

i = 255;

goto done;

}

reftype = get_ref_type(c, name);

switch (reftype) {

case LOCAL:

if (c->c_symtable->st_cur->ste_type == TYPE_FUNCTION)

scope = NAME_LOCAL;

break;

case GLOBAL_EXPLICIT:

scope = NAME_GLOBAL;

break;

case GLOBAL_IMPLICIT:

if (c->c_flags & CO_OPTIMIZED)

scope = NAME_GLOBAL;

break;

case FREE:

case CELL:

scope = NAME_CLOSURE;

break;

}

i = com_addname(c, v);

if (scope == NAME_LOCAL)

i = com_lookup_arg(c->c_locals, v);

else if (reftype == FREE)

i = com_lookup_arg(c->c_freevars, v);

else if (reftype == CELL)

i = com_lookup_arg(c->c_cellvars, v);

if (i == -1) {

c->c_errors++; /* XXX no exception set */

i = 255;

goto done;

}

Py_DECREF(v);

switch (kind) {

case VAR_LOAD:

switch (scope) {

case NAME_LOCAL:

op = LOAD_FAST;

break;

case NAME_GLOBAL:

op = LOAD_GLOBAL;

break;

case NAME_DEFAULT:

op = LOAD_NAME;

break;

case NAME_CLOSURE:

op = LOAD_DEREF;

break;

}

break;

case VAR_STORE:

switch (scope) {

case NAME_LOCAL:

op = STORE_FAST;

break;

case NAME_GLOBAL:

op = STORE_GLOBAL;

break;

case NAME_DEFAULT:

op = STORE_NAME;

break;

case NAME_CLOSURE:

op = STORE_DEREF;