/***********************************************************

Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The

Netherlands.

All Rights Reserved

Permission to use, copy, modify, and distribute this software and its

documentation for any purpose and without fee is hereby granted,

provided that the above copyright notice appear in all copies and that

both that copyright notice and this permission notice appear in

supporting documentation, and that the names of Stichting Mathematisch

Centrum or CWI not be used in advertising or publicity pertaining to

distribution of the software without specific, written prior permission.

STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO

THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND

FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE

FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT

OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

/* Execute compiled code */

#include "allobjects.h"

#include "import.h"

#include "sysmodule.h"

#include "compile.h"

#include "frameobject.h"

#include "ceval.h"

#include "opcode.h"

#include "bltinmodule.h"

#include "traceback.h"

#ifndef NDEBUG

/* For debugging the interpreter: */

#define LLTRACE 1 /* Low-level trace feature */

#define CHECKEXC 1 /* Double-check exception checking */

#endif

/* Forward declarations */

#ifdef LLTRACE

static int prtrace PROTO((object *, char *));

#endif

static void call_exc_trace PROTO((object **, object**, frameobject *));

static int call_trace

PROTO((object **, object **, frameobject *, char *, object *));

static int testbool PROTO((object *));

static object *add PROTO((object *, object *));

static object *sub PROTO((object *, object *));

static object *mul PROTO((object *, object *));

static object *divide PROTO((object *, object *));

static object *rem PROTO((object *, object *));

static object *neg PROTO((object *));

static object *pos PROTO((object *));

static object *not PROTO((object *));

static object *invert PROTO((object *));

static object *lshift PROTO((object *, object *));

static object *rshift PROTO((object *, object *));

static object *and PROTO((object *, object *));

static object *xor PROTO((object *, object *));

static object *or PROTO((object *, object *));

static object *call_builtin PROTO((object *, object *));

static object *call_function PROTO((object *, object *));

static object *apply_subscript PROTO((object *, object *));

static object *loop_subscript PROTO((object *, object *));

static int slice_index PROTO((object *, int, int *));

static object *apply_slice PROTO((object *, object *, object *));

static int assign_subscript PROTO((object *, object *, object *));

static int assign_slice PROTO((object *, object *, object *, object *));

static int cmp_exception PROTO((object *, object *));

static int cmp_member PROTO((object *, object *));

static object *cmp_outcome PROTO((enum cmp_op, object *, object *));

static int import_from PROTO((object *, object *, object *));

static object *build_class PROTO((object *, object *));

/* Pointer to current frame, used to link new frames to */

static frameobject *current_frame;

/* Status code for main loop (reason for stack unwind) */

enum why_code {

WHY_NOT, /* No error */

WHY_EXCEPTION, /* Exception occurred */

WHY_RERAISE, /* Exception re-raised by 'finally' */

WHY_RETURN, /* 'return' statement */

WHY_BREAK /* 'break' statement */

};

/* Interpreter main loop */

object *

eval_code(co, globals, locals, arg)

codeobject *co;

object *globals;

object *locals;

object *arg;

{

register unsigned char *next_instr;

register int opcode; /* Current opcode */

register int oparg; /* Current opcode argument, if any */

register object **stack_pointer;

register enum why_code why; /* Reason for block stack unwind */

register int err; /* Error status -- nonzero if error */

register object *x; /* Result object -- NULL if error */

register object *v; /* Temporary objects popped off stack */

register object *w;

register object *u;

register object *t;

register frameobject *f; /* Current frame */

object *trace = NULL; /* Trace function or NULL */

object *retval; /* Return value iff why == WHY_RETURN */

char *name; /* Name used by some instructions */

FILE *fp; /* Used by print operations */

#ifdef LLTRACE

int lltrace = dictlookup(globals, "__lltrace__") != NULL;

#endif

/* Code access macros */

#define GETCONST(i) Getconst(f, i)

#define GETNAME(i) Getname(f, i)

#define GETNAMEV(i) Getnamev(f, i)

#define FIRST_INSTR() (GETUSTRINGVALUE(f->f_code->co_code))

#define INSTR_OFFSET() (next_instr - FIRST_INSTR())

#define NEXTOP() (*next_instr++)

#define NEXTARG() (next_instr += 2, (next_instr[-1]<<8) + next_instr[-2])

#define JUMPTO(x) (next_instr = FIRST_INSTR() + (x))

#define JUMPBY(x) (next_instr += (x))

/* Stack manipulation macros */

#define STACK_LEVEL() (stack_pointer - f->f_valuestack)

#define EMPTY() (STACK_LEVEL() == 0)

#define TOP() (stack_pointer[-1])

#define BASIC_PUSH(v) (*stack_pointer++ = (v))

#define BASIC_POP() (*--stack_pointer)

#ifdef LLTRACE

#define PUSH(v) (BASIC_PUSH(v), lltrace && prtrace(TOP(), "push"))

#define POP() (lltrace && prtrace(TOP(), "pop"), BASIC_POP())

#else

#define PUSH(v) BASIC_PUSH(v)

#define POP() BASIC_POP()

#endif

f = newframeobject(

current_frame, /*back*/

co, /*code*/

globals, /*globals*/

locals, /*locals*/

50, /*nvalues*/

20); /*nblocks*/

if (f == NULL)

return NULL;

current_frame = f;

if (sys_trace != NULL) {

/* sys_trace, if defined, is a function that will

be called on *every* entry to a code block.

Its return value, if not None, is a function that

will be called at the start of each executed line

of code. (Actually, the function must return

itself in order to continue tracing.)

The trace functions are called with three arguments:

a pointer to the current frame, a string indicating

why the function is called, and an argument which

depends on the situation. The global trace function

(sys.trace) is also called whenever an exception

is detected. */

if (call_trace(&sys_trace, &trace, f, "call", arg)) {

/* Trace function raised an error */

current_frame = f->f_back;

DECREF(f);

return NULL;

}

}

if (sys_profile != NULL) {

/* Similar for sys_profile, except it needn't return

itself and isn't called for "line" events */

if (call_trace(&sys_profile, (object**)0, f, "call", arg)) {

current_frame = f->f_back;

DECREF(f);

return NULL;

}

}

next_instr = GETUSTRINGVALUE(f->f_code->co_code);

stack_pointer = f->f_valuestack;

if (arg != NULL) {

INCREF(arg);

PUSH(arg);

}

why = WHY_NOT;

err = 0;

x = None; /* Not a reference, just anything non-NULL */

for (;;) {

static int ticker;

/* Do periodic things */

if (--ticker < 0) {

ticker = 100;

if (intrcheck()) {

err_set(KeyboardInterrupt);

why = WHY_EXCEPTION;

goto on_error;

}

}

/* Extract opcode and argument */

opcode = NEXTOP();

if (HAS_ARG(opcode))

oparg = NEXTARG();

#ifdef LLTRACE

/* Instruction tracing */

if (lltrace) {

if (HAS_ARG(opcode)) {

printf("%d: %d, %d\n",

(int) (INSTR_OFFSET() - 3),

opcode, oparg);

}

else {

printf("%d: %d\n",

(int) (INSTR_OFFSET() - 1), opcode);

}

}

#endif

/* Main switch on opcode */

switch (opcode) {

/* BEWARE!

It is essential that any operation that fails sets either

x to NULL, err to nonzero, or why to anything but WHY_NOT,

and that no operation that succeeds does this! */

/* case STOP_CODE: this is an error! */

case POP_TOP:

v = POP();

DECREF(v);

break;

case ROT_TWO:

v = POP();

w = POP();

PUSH(v);

PUSH(w);

break;

case ROT_THREE:

v = POP();

w = POP();

x = POP();

PUSH(v);

PUSH(x);

PUSH(w);

break;

case DUP_TOP:

v = TOP();

INCREF(v);

PUSH(v);

break;

case UNARY_POSITIVE:

v = POP();

x = pos(v);

DECREF(v);

PUSH(x);

break;

case UNARY_NEGATIVE:

v = POP();

x = neg(v);

DECREF(v);

PUSH(x);

break;

case UNARY_NOT:

v = POP();

x = not(v);

DECREF(v);

PUSH(x);

break;

case UNARY_CONVERT:

v = POP();

x = reprobject(v);

DECREF(v);

PUSH(x);

break;

case UNARY_CALL:

v = POP();

f->f_lasti = INSTR_OFFSET() - 1; /* For tracing */

x = call_object(v, (object *)NULL);

DECREF(v);

PUSH(x);

break;

case UNARY_INVERT:

v = POP();

x = invert(v);

DECREF(v);

PUSH(x);

break;

case BINARY_MULTIPLY:

w = POP();

v = POP();

x = mul(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_DIVIDE:

w = POP();

v = POP();

x = divide(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_MODULO:

w = POP();

v = POP();

x = rem(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_ADD:

w = POP();

v = POP();

x = add(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_SUBTRACT:

w = POP();

v = POP();

x = sub(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_SUBSCR:

w = POP();

v = POP();

x = apply_subscript(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_CALL:

w = POP();

v = POP();

f->f_lasti = INSTR_OFFSET() - 1; /* For tracing */

x = call_object(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_LSHIFT:

w = POP();

v = POP();

x = lshift(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_RSHIFT:

w = POP();

v = POP();

x = rshift(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_AND:

w = POP();

v = POP();

x = and(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_XOR:

w = POP();

v = POP();

x = xor(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case BINARY_OR:

w = POP();

v = POP();

x = or(v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case SLICE+0:

case SLICE+1:

case SLICE+2:

case SLICE+3:

if ((opcode-SLICE) & 2)

w = POP();

else

w = NULL;

if ((opcode-SLICE) & 1)

v = POP();

else

v = NULL;

u = POP();

x = apply_slice(u, v, w);

DECREF(u);

XDECREF(v);

XDECREF(w);

PUSH(x);

break;

case STORE_SLICE+0:

case STORE_SLICE+1:

case STORE_SLICE+2:

case STORE_SLICE+3:

if ((opcode-STORE_SLICE) & 2)

w = POP();

else

w = NULL;

if ((opcode-STORE_SLICE) & 1)

v = POP();

else

v = NULL;

u = POP();

t = POP();

err = assign_slice(u, v, w, t); /* u[v:w] = t */

DECREF(t);

DECREF(u);

XDECREF(v);

XDECREF(w);

break;

case DELETE_SLICE+0:

case DELETE_SLICE+1:

case DELETE_SLICE+2:

case DELETE_SLICE+3:

if ((opcode-DELETE_SLICE) & 2)

w = POP();

else

w = NULL;

if ((opcode-DELETE_SLICE) & 1)

v = POP();

else

v = NULL;

u = POP();

err = assign_slice(u, v, w, (object *)NULL);

/* del u[v:w] */

DECREF(u);

XDECREF(v);

XDECREF(w);

break;

case STORE_SUBSCR:

w = POP();

v = POP();

u = POP();

/* v[w] = u */

err = assign_subscript(v, w, u);

DECREF(u);

DECREF(v);

DECREF(w);

break;

case DELETE_SUBSCR:

w = POP();

v = POP();

/* del v[w] */

err = assign_subscript(v, w, (object *)NULL);

DECREF(v);

DECREF(w);

break;

case PRINT_EXPR:

v = POP();

fp = sysgetfile("stdout", stdout);

/* Print value except if procedure result */

if (v != None) {

flushline();

softspace(sysget("stdout"), 1);

err = printobject(v, fp, 0);

flushline();

}

DECREF(v);

break;

case PRINT_ITEM:

v = POP();

fp = sysgetfile("stdout", stdout);

if (softspace(sysget("stdout"), 1))

fprintf(fp, " ");

if (is_stringobject(v)) {

char *s = getstringvalue(v);

int len = getstringsize(v);

fwrite(s, 1, len, fp);

if (ferror(fp)) {

err_errno(IOError);

err = -1;

}

else if (len > 0 && s[len-1] == '\n')

softspace(sysget("stdout"), 0);

}

else {

err = printobject(v, fp, 0);

}

DECREF(v);

break;

case PRINT_NEWLINE:

fp = sysgetfile("stdout", stdout);

fprintf(fp, "\n");

softspace(sysget("stdout"), 0);

break;

case BREAK_LOOP:

why = WHY_BREAK;

break;

case RAISE_EXCEPTION:

v = POP();

w = POP();

/* A tuple is equivalent to its first element here */

while (is_tupleobject(w)) {

u = w;

w = gettupleitem(u, 0);

DECREF(u);

}

if (!is_stringobject(w))

err_setstr(TypeError,

"exceptions must be strings");

else

err_setval(w, v);

DECREF(v);

DECREF(w);

why = WHY_EXCEPTION;

break;

case LOAD_LOCALS:

v = f->f_locals;

INCREF(v);

PUSH(v);

break;

case RETURN_VALUE:

retval = POP();

why = WHY_RETURN;

break;

case BUILD_FUNCTION:

v = POP();

x = newfuncobject(v, f->f_globals);

DECREF(v);

PUSH(x);

break;

case POP_BLOCK:

{

block *b = pop_block(f);

while (STACK_LEVEL() > b->b_level) {

v = POP();

DECREF(v);

}

}

break;

case END_FINALLY:

v = POP();

if (is_intobject(v)) {

why = (enum why_code) getintvalue(v);

if (why == WHY_RETURN)

retval = POP();

}

else if (is_stringobject(v)) {

w = POP();

err_setval(v, w);

DECREF(w);

w = POP();

tb_store(w);

DECREF(w);

why = WHY_RERAISE;

}

else if (v != None) {

err_setstr(SystemError,

"'finally' pops bad exception");

why = WHY_EXCEPTION;

}

DECREF(v);

break;

case BUILD_CLASS:

w = POP();

v = POP();

x = build_class(v, w);

PUSH(x);

DECREF(v);

DECREF(w);

break;

case STORE_NAME:

w = GETNAMEV(oparg);

v = POP();

err = dict2insert(f->f_locals, w, v);

DECREF(v);

break;

case DELETE_NAME:

w = GETNAMEV(oparg);

if ((err = dict2remove(f->f_locals, w)) != 0)

err_setstr(NameError, getstringvalue(w));

break;

case UNPACK_VARARG:

if (EMPTY()) {

err_setstr(TypeError,

"no argument list");

why = WHY_EXCEPTION;

break;

}

v = POP();

if (!is_tupleobject(v)) {

err_setstr(TypeError,

"bad argument list");

why = WHY_EXCEPTION;

}

else if (gettuplesize(v) < oparg) {

err_setstr(TypeError,

"not enough arguments");

why = WHY_EXCEPTION;

}

else if (oparg == 0) {

PUSH(v);

break;

}

else {

x = gettupleslice(v, oparg, gettuplesize(v));

if (x != NULL) {

PUSH(x);

for (; --oparg >= 0; ) {

w = gettupleitem(v, oparg);

INCREF(w);

PUSH(w);

}

}

}

DECREF(v);

break;

case UNPACK_ARG:

/* Implement various compatibility hacks:

(a) f(a,b,...) should accept f((1,2,...))

(b) f((a,b,...)) should accept f(1,2,...)

(c) f(self,(a,b,...)) should accept f(x,1,2,...)

*/

{

int n;

if (EMPTY()) {

err_setstr(TypeError,

"no argument list");

why = WHY_EXCEPTION;

break;

}

v = POP();

if (!is_tupleobject(v)) {

err_setstr(TypeError,

"bad argument list");

why = WHY_EXCEPTION;

break;

}

n = gettuplesize(v);

if (n == 1 && oparg != 1) {

/* Rule (a) */

w = gettupleitem(v, 0);

if (is_tupleobject(w)) {

INCREF(w);

DECREF(v);

v = w;

n = gettuplesize(v);

}

}

else if (n != 1 && oparg == 1) {

/* Rule (b) */

PUSH(v);

break;

/* Don't fall through */

}

else if (n > 2 && oparg == 2) {

/* Rule (c) */

int i;

w = newtupleobject(n-1);

u = newtupleobject(2);

if (u == NULL || w == NULL) {

XDECREF(w);

XDECREF(u);

DECREF(v);

why = WHY_EXCEPTION;

break;

}

t = gettupleitem(v, 0);

INCREF(t);

settupleitem(u, 0, t);

for (i = 1; i < n; i++) {

t = gettupleitem(v, i);

INCREF(t);

settupleitem(w, i-1, t);

}

settupleitem(u, 1, w);

DECREF(v);

v = u;

n = 2;

}

if (n != oparg) {

err_setstr(TypeError,

"arg count mismatch");

why = WHY_EXCEPTION;

DECREF(v);

break;

}

PUSH(v);

}

/* Fall through */

case UNPACK_TUPLE:

v = POP();

if (!is_tupleobject(v)) {

err_setstr(TypeError, "unpack non-tuple");

why = WHY_EXCEPTION;

}

else if (gettuplesize(v) != oparg) {

err_setstr(ValueError,

"unpack tuple of wrong size");

why = WHY_EXCEPTION;

}

else {

for (; --oparg >= 0; ) {

w = gettupleitem(v, oparg);

INCREF(w);

PUSH(w);

}

}

DECREF(v);

break;

case UNPACK_LIST:

v = POP();

if (!is_listobject(v)) {

err_setstr(TypeError, "unpack non-list");

why = WHY_EXCEPTION;

}

else if (getlistsize(v) != oparg) {

err_setstr(ValueError,

"unpack list of wrong size");

why = WHY_EXCEPTION;

}

else {

for (; --oparg >= 0; ) {

w = getlistitem(v, oparg);

INCREF(w);

PUSH(w);

}

}

DECREF(v);

break;

case STORE_ATTR:

name = GETNAME(oparg);

v = POP();

u = POP();

err = setattr(v, name, u); /* v.name = u */

DECREF(v);

DECREF(u);

break;

case DELETE_ATTR:

name = GETNAME(oparg);

v = POP();

err = setattr(v, name, (object *)NULL);

/* del v.name */

DECREF(v);

break;

case STORE_GLOBAL:

w = GETNAMEV(oparg);

v = POP();

err = dict2insert(f->f_globals, w, v);

DECREF(v);

break;

case DELETE_GLOBAL:

w = GETNAMEV(oparg);

if ((err = dict2remove(f->f_globals, w)) != 0)

err_setstr(NameError, getstringvalue(w));

break;

case LOAD_CONST:

x = GETCONST(oparg);

INCREF(x);

PUSH(x);

break;

case LOAD_NAME:

w = GETNAMEV(oparg);

x = dict2lookup(f->f_locals, w);

if (x == NULL) {

err_clear();

x = dict2lookup(f->f_globals, w);

if (x == NULL) {

err_clear();

x = getbuiltin(w);

if (x == NULL) {

err_setstr(NameError,

getstringvalue(w));

break;

}

}

}

INCREF(x);

PUSH(x);

break;

case LOAD_GLOBAL:

w = GETNAMEV(oparg);

x = dict2lookup(f->f_globals, w);

if (x == NULL) {

err_clear();

x = getbuiltin(w);

if (x == NULL) {

err_setstr(NameError,

getstringvalue(w));

break;

}

}

INCREF(x);

PUSH(x);

break;

case LOAD_LOCAL:

w = GETNAMEV(oparg);

x = dict2lookup(f->f_locals, w);

if (x == NULL) {

err_setstr(NameError, getstringvalue(w));

break;

}

INCREF(x);

PUSH(x);

break;

case BUILD_TUPLE:

x = newtupleobject(oparg);

if (x != NULL) {

for (; --oparg >= 0;) {

w = POP();

err = settupleitem(x, oparg, w);

if (err != 0)

break;

}

PUSH(x);

}

break;

case BUILD_LIST:

x = newlistobject(oparg);

if (x != NULL) {

for (; --oparg >= 0;) {

w = POP();

err = setlistitem(x, oparg, w);

if (err != 0)

break;

}

PUSH(x);

}

break;

case BUILD_MAP:

x = newdictobject();

PUSH(x);

break;

case LOAD_ATTR:

name = GETNAME(oparg);

v = POP();

x = getattr(v, name);

DECREF(v);

PUSH(x);

break;

case COMPARE_OP:

w = POP();

v = POP();

x = cmp_outcome((enum cmp_op)oparg, v, w);

DECREF(v);

DECREF(w);

PUSH(x);

break;

case IMPORT_NAME:

name = GETNAME(oparg);

x = import_module(name);

XINCREF(x);

PUSH(x);

break;

case IMPORT_FROM:

w = GETNAMEV(oparg);

v = TOP();

err = import_from(f->f_locals, v, w);

break;

case JUMP_FORWARD:

JUMPBY(oparg);

break;

case JUMP_IF_FALSE:

if (!testbool(TOP()))

JUMPBY(oparg);

break;

case JUMP_IF_TRUE:

if (testbool(TOP()))

JUMPBY(oparg);

break;

case JUMP_ABSOLUTE:

JUMPTO(oparg);

break;

case FOR_LOOP:

/* for v in s: ...

On entry: stack contains s, i.

On exit: stack contains s, i+1, s[i];

but if loop exhausted:

s, i are popped, and we jump */

w = POP(); /* Loop index */

v = POP(); /* Sequence object */

u = loop_subscript(v, w);

if (u != NULL) {

PUSH(v);

x = newintobject(getintvalue(w)+1);

PUSH(x);

DECREF(w);

PUSH(u);

}

else {

DECREF(v);

DECREF(w);

/* A NULL can mean "s exhausted"

but also an error: */

if (err_occurred())

why = WHY_EXCEPTION;

else

JUMPBY(oparg);

}

break;

case SETUP_LOOP:

case SETUP_EXCEPT:

case SETUP_FINALLY:

setup_block(f, opcode, INSTR_OFFSET() + oparg,

STACK_LEVEL());