/* Execute compiled code */

/* XXX TO DO:

XXX speed up searching for keywords by using a dictionary

XXX document it!

*/

/* enable more aggressive intra-module optimizations, where available */

#define PY_LOCAL_AGGRESSIVE

#include "Python.h"

#include "code.h"

#include "frameobject.h"

#include "eval.h"

#include "opcode.h"

#include "structmember.h"

#include <ctype.h>

#ifndef WITH_TSC

#define READ_TIMESTAMP(var)

#else

typedef unsigned long long uint64;

#if defined(__ppc__) /* <- Don't know if this is the correct symbol; this

section should work for GCC on any PowerPC

platform, irrespective of OS.

POWER? Who knows :-) */

#define READ_TIMESTAMP(var) ppc_getcounter(&var)

static void

ppc_getcounter(uint64 *v)

{

register unsigned long tbu, tb, tbu2;

loop:

asm volatile ("mftbu %0" : "=r" (tbu) );

asm volatile ("mftb %0" : "=r" (tb) );

asm volatile ("mftbu %0" : "=r" (tbu2));

if (__builtin_expect(tbu != tbu2, 0)) goto loop;

/* The slightly peculiar way of writing the next lines is

compiled better by GCC than any other way I tried. */

((long*)(v))[0] = tbu;

((long*)(v))[1] = tb;

}

#else /* this is for linux/x86 (and probably any other GCC/x86 combo) */

#define READ_TIMESTAMP(val) \

__asm__ __volatile__("rdtsc" : "=A" (val))

#endif

void dump_tsc(int opcode, int ticked, uint64 inst0, uint64 inst1,

uint64 loop0, uint64 loop1, uint64 intr0, uint64 intr1)

{

uint64 intr, inst, loop;

PyThreadState *tstate = PyThreadState_Get();

if (!tstate->interp->tscdump)

return;

intr = intr1 - intr0;

inst = inst1 - inst0 - intr;

loop = loop1 - loop0 - intr;

fprintf(stderr, "opcode=%03d t=%d inst=%06lld loop=%06lld\n",

opcode, ticked, inst, loop);

}

#endif

/* Turn this on if your compiler chokes on the big switch: */

/* #define CASE_TOO_BIG 1 */

#ifdef Py_DEBUG

/* For debugging the interpreter: */

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

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

#endif

typedef PyObject *(*callproc)(PyObject *, PyObject *, PyObject *);

/* Forward declarations */

#ifdef WITH_TSC

static PyObject * call_function(PyObject ***, int, uint64*, uint64*);

#else

static PyObject * call_function(PyObject ***, int);

#endif

static PyObject * fast_function(PyObject *, PyObject ***, int, int, int);

static PyObject * do_call(PyObject *, PyObject ***, int, int);

static PyObject * ext_do_call(PyObject *, PyObject ***, int, int, int);

static PyObject * update_keyword_args(PyObject *, int, PyObject ***,

PyObject *);

static PyObject * update_star_args(int, int, PyObject *, PyObject ***);

static PyObject * load_args(PyObject ***, int);

#define CALL_FLAG_VAR 1

#define CALL_FLAG_KW 2

#ifdef LLTRACE

static int lltrace;

static int prtrace(PyObject *, char *);

#endif

static int call_trace(Py_tracefunc, PyObject *, PyFrameObject *,

int, PyObject *);

static int call_trace_protected(Py_tracefunc, PyObject *,

PyFrameObject *, int, PyObject *);

static void call_exc_trace(Py_tracefunc, PyObject *, PyFrameObject *);

static int maybe_call_line_trace(Py_tracefunc, PyObject *,

PyFrameObject *, int *, int *, int *);

static PyObject * cmp_outcome(int, PyObject *, PyObject *);

static PyObject * import_from(PyObject *, PyObject *);

static int import_all_from(PyObject *, PyObject *);

static void set_exc_info(PyThreadState *, PyObject *, PyObject *, PyObject *);

static void reset_exc_info(PyThreadState *);

static void format_exc_check_arg(PyObject *, const char *, PyObject *);

static PyObject * unicode_concatenate(PyObject *, PyObject *,

PyFrameObject *, unsigned char *);

#define NAME_ERROR_MSG \

"name '%.200s' is not defined"

#define GLOBAL_NAME_ERROR_MSG \

"global name '%.200s' is not defined"

#define UNBOUNDLOCAL_ERROR_MSG \

"local variable '%.200s' referenced before assignment"

#define UNBOUNDFREE_ERROR_MSG \

"free variable '%.200s' referenced before assignment" \

" in enclosing scope"

/* Dynamic execution profile */

#ifdef DYNAMIC_EXECUTION_PROFILE

#ifdef DXPAIRS

static long dxpairs[257][256];

#define dxp dxpairs[256]

#else

static long dxp[256];

#endif

#endif

/* Function call profile */

#ifdef CALL_PROFILE

#define PCALL_NUM 11

static int pcall[PCALL_NUM];

#define PCALL_ALL 0

#define PCALL_FUNCTION 1

#define PCALL_FAST_FUNCTION 2

#define PCALL_FASTER_FUNCTION 3

#define PCALL_METHOD 4

#define PCALL_BOUND_METHOD 5

#define PCALL_CFUNCTION 6

#define PCALL_TYPE 7

#define PCALL_GENERATOR 8

#define PCALL_OTHER 9

#define PCALL_POP 10

/* Notes about the statistics

PCALL_FAST stats

FAST_FUNCTION means no argument tuple needs to be created.

FASTER_FUNCTION means that the fast-path frame setup code is used.

If there is a method call where the call can be optimized by changing

the argument tuple and calling the function directly, it gets recorded

twice.

As a result, the relationship among the statistics appears to be

PCALL_ALL == PCALL_FUNCTION + PCALL_METHOD - PCALL_BOUND_METHOD +

PCALL_CFUNCTION + PCALL_TYPE + PCALL_GENERATOR + PCALL_OTHER

PCALL_FUNCTION > PCALL_FAST_FUNCTION > PCALL_FASTER_FUNCTION

PCALL_METHOD > PCALL_BOUND_METHOD

*/

#define PCALL(POS) pcall[POS]++

PyObject *

PyEval_GetCallStats(PyObject *self)

{

return Py_BuildValue("iiiiiiiiiii",

pcall[0], pcall[1], pcall[2], pcall[3],

pcall[4], pcall[5], pcall[6], pcall[7],

pcall[8], pcall[9], pcall[10]);

}

#else

#define PCALL(O)

PyObject *

PyEval_GetCallStats(PyObject *self)

{

Py_INCREF(Py_None);

return Py_None;

}

#endif

#ifdef WITH_THREAD

#ifdef HAVE_ERRNO_H

#include <errno.h>

#endif

#include "pythread.h"

static PyThread_type_lock interpreter_lock = 0; /* This is the GIL */

static long main_thread = 0;

int

PyEval_ThreadsInitialized(void)

{

return interpreter_lock != 0;

}

void

PyEval_InitThreads(void)

{

if (interpreter_lock)

return;

interpreter_lock = PyThread_allocate_lock();

PyThread_acquire_lock(interpreter_lock, 1);

main_thread = PyThread_get_thread_ident();

}

void

PyEval_AcquireLock(void)

{

PyThread_acquire_lock(interpreter_lock, 1);

}

void

PyEval_ReleaseLock(void)

{

PyThread_release_lock(interpreter_lock);

}

void

PyEval_AcquireThread(PyThreadState *tstate)

{

if (tstate == NULL)

Py_FatalError("PyEval_AcquireThread: NULL new thread state");

/* Check someone has called PyEval_InitThreads() to create the lock */

assert(interpreter_lock);

PyThread_acquire_lock(interpreter_lock, 1);

if (PyThreadState_Swap(tstate) != NULL)

Py_FatalError(

"PyEval_AcquireThread: non-NULL old thread state");

}

void

PyEval_ReleaseThread(PyThreadState *tstate)

{

if (tstate == NULL)

Py_FatalError("PyEval_ReleaseThread: NULL thread state");

if (PyThreadState_Swap(NULL) != tstate)

Py_FatalError("PyEval_ReleaseThread: wrong thread state");

PyThread_release_lock(interpreter_lock);

}

/* This function is called from PyOS_AfterFork to ensure that newly

created child processes don't hold locks referring to threads which

are not running in the child process. (This could also be done using

pthread_atfork mechanism, at least for the pthreads implementation.) */

void

PyEval_ReInitThreads(void)

{

if (!interpreter_lock)

return;

/*XXX Can't use PyThread_free_lock here because it does too

much error-checking. Doing this cleanly would require

adding a new function to each thread_*.h. Instead, just

create a new lock and waste a little bit of memory */

interpreter_lock = PyThread_allocate_lock();

PyThread_acquire_lock(interpreter_lock, 1);

main_thread = PyThread_get_thread_ident();

}

#endif

/* Functions save_thread and restore_thread are always defined so

dynamically loaded modules needn't be compiled separately for use

with and without threads: */

PyThreadState *

PyEval_SaveThread(void)

{

PyThreadState *tstate = PyThreadState_Swap(NULL);

if (tstate == NULL)

Py_FatalError("PyEval_SaveThread: NULL tstate");

#ifdef WITH_THREAD

if (interpreter_lock)

PyThread_release_lock(interpreter_lock);

#endif

return tstate;

}

void

PyEval_RestoreThread(PyThreadState *tstate)

{

if (tstate == NULL)

Py_FatalError("PyEval_RestoreThread: NULL tstate");

#ifdef WITH_THREAD

if (interpreter_lock) {

int err = errno;

PyThread_acquire_lock(interpreter_lock, 1);

errno = err;

}

#endif

PyThreadState_Swap(tstate);

}

/* Mechanism whereby asynchronously executing callbacks (e.g. UNIX

signal handlers or Mac I/O completion routines) can schedule calls

to a function to be called synchronously.

The synchronous function is called with one void* argument.

It should return 0 for success or -1 for failure -- failure should

be accompanied by an exception.

If registry succeeds, the registry function returns 0; if it fails

(e.g. due to too many pending calls) it returns -1 (without setting

an exception condition).

Note that because registry may occur from within signal handlers,

or other asynchronous events, calling malloc() is unsafe!

#ifdef WITH_THREAD

Any thread can schedule pending calls, but only the main thread

will execute them.

#endif

XXX WARNING! ASYNCHRONOUSLY EXECUTING CODE!

There are two possible race conditions:

(1) nested asynchronous registry calls;

(2) registry calls made while pending calls are being processed.

While (1) is very unlikely, (2) is a real possibility.

The current code is safe against (2), but not against (1).

The safety against (2) is derived from the fact that only one

thread (the main thread) ever takes things out of the queue.

XXX Darn! With the advent of thread state, we should have an array

of pending calls per thread in the thread state! Later...

*/

#define NPENDINGCALLS 32

static struct {

int (*func)(void *);

void *arg;

} pendingcalls[NPENDINGCALLS];

static volatile int pendingfirst = 0;

static volatile int pendinglast = 0;

static volatile int things_to_do = 0;

int

Py_AddPendingCall(int (*func)(void *), void *arg)

{

static volatile int busy = 0;

int i, j;

/* XXX Begin critical section */

/* XXX If you want this to be safe against nested

XXX asynchronous calls, you'll have to work harder! */

if (busy)

return -1;

busy = 1;

i = pendinglast;

j = (i + 1) % NPENDINGCALLS;

if (j == pendingfirst) {

busy = 0;

return -1; /* Queue full */

}

pendingcalls[i].func = func;

pendingcalls[i].arg = arg;

pendinglast = j;

_Py_Ticker = 0;

things_to_do = 1; /* Signal main loop */

busy = 0;

/* XXX End critical section */

return 0;

}

int

Py_MakePendingCalls(void)

{

static int busy = 0;

#ifdef WITH_THREAD

if (main_thread && PyThread_get_thread_ident() != main_thread)

return 0;

#endif

if (busy)

return 0;

busy = 1;

things_to_do = 0;

for (;;) {

int i;

int (*func)(void *);

void *arg;

i = pendingfirst;

if (i == pendinglast)

break; /* Queue empty */

func = pendingcalls[i].func;

arg = pendingcalls[i].arg;

pendingfirst = (i + 1) % NPENDINGCALLS;

if (func(arg) < 0) {

busy = 0;

things_to_do = 1; /* We're not done yet */

return -1;

}

}

busy = 0;

return 0;

}

/* The interpreter's recursion limit */

#ifndef Py_DEFAULT_RECURSION_LIMIT

#define Py_DEFAULT_RECURSION_LIMIT 1000

#endif

static int recursion_limit = Py_DEFAULT_RECURSION_LIMIT;

int _Py_CheckRecursionLimit = Py_DEFAULT_RECURSION_LIMIT;

int

Py_GetRecursionLimit(void)

{

return recursion_limit;

}

void

Py_SetRecursionLimit(int new_limit)

{

recursion_limit = new_limit;

_Py_CheckRecursionLimit = recursion_limit;

}

/* the macro Py_EnterRecursiveCall() only calls _Py_CheckRecursiveCall()

if the recursion_depth reaches _Py_CheckRecursionLimit.

If USE_STACKCHECK, the macro decrements _Py_CheckRecursionLimit

to guarantee that _Py_CheckRecursiveCall() is regularly called.

Without USE_STACKCHECK, there is no need for this. */

int

_Py_CheckRecursiveCall(char *where)

{

PyThreadState *tstate = PyThreadState_GET();

#ifdef USE_STACKCHECK

if (PyOS_CheckStack()) {

--tstate->recursion_depth;

PyErr_SetString(PyExc_MemoryError, "Stack overflow");

return -1;

}

#endif

if (tstate->recursion_critical)

/* Somebody asked that we don't check for recursion. */

return 0;

if (tstate->overflowed) {

if (tstate->recursion_depth > recursion_limit + 50) {

/* Overflowing while handling an overflow. Give up. */

Py_FatalError("Cannot recover from stack overflow.");

}

return 0;

}

if (tstate->recursion_depth > recursion_limit) {

--tstate->recursion_depth;

tstate->overflowed = 1;

PyErr_Format(PyExc_RuntimeError,

"maximum recursion depth exceeded%s",

where);

return -1;

}

_Py_CheckRecursionLimit = recursion_limit;

return 0;

}

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

enum why_code {

WHY_NOT = 0x0001, /* No error */

WHY_EXCEPTION = 0x0002, /* Exception occurred */

WHY_RERAISE = 0x0004, /* Exception re-raised by 'finally' */

WHY_RETURN = 0x0008, /* 'return' statement */

WHY_BREAK = 0x0010, /* 'break' statement */

WHY_CONTINUE = 0x0020, /* 'continue' statement */

WHY_YIELD = 0x0040 /* 'yield' operator */

};

static enum why_code do_raise(PyObject *, PyObject *);

static int unpack_iterable(PyObject *, int, int, PyObject **);

/* for manipulating the thread switch and periodic "stuff" - used to be

per thread, now just a pair o' globals */

int _Py_CheckInterval = 100;

volatile int _Py_Ticker = 100;

PyObject *

PyEval_EvalCode(PyCodeObject *co, PyObject *globals, PyObject *locals)

{

return PyEval_EvalCodeEx(co,

globals, locals,

(PyObject **)NULL, 0,

(PyObject **)NULL, 0,

(PyObject **)NULL, 0,

NULL, NULL);

}

/* Interpreter main loop */

PyObject *

PyEval_EvalFrame(PyFrameObject *f) {

/* This is for backward compatibility with extension modules that

used this API; core interpreter code should call

PyEval_EvalFrameEx() */

return PyEval_EvalFrameEx(f, 0);

}

PyObject *

PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)

{

#ifdef DXPAIRS

int lastopcode = 0;

#endif

register PyObject **stack_pointer; /* Next free slot in value stack */

register unsigned char *next_instr;

register int opcode; /* Current opcode */

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

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

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

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

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

register PyObject *w;

register PyObject *u;

register PyObject *t;

register PyObject **fastlocals, **freevars;

PyObject *retval = NULL; /* Return value */

PyThreadState *tstate = PyThreadState_GET();

PyCodeObject *co;

/* when tracing we set things up so that

not (instr_lb <= current_bytecode_offset < instr_ub)

is true when the line being executed has changed. The

initial values are such as to make this false the first

time it is tested. */

int instr_ub = -1, instr_lb = 0, instr_prev = -1;

unsigned char *first_instr;

PyObject *names;

PyObject *consts;

#if defined(Py_DEBUG) || defined(LLTRACE)

/* Make it easier to find out where we are with a debugger */

char *filename;

#endif

/* Tuple access macros */

#ifndef Py_DEBUG

#define GETITEM(v, i) PyTuple_GET_ITEM((PyTupleObject *)(v), (i))

#else

#define GETITEM(v, i) PyTuple_GetItem((v), (i))

#endif

#ifdef WITH_TSC

/* Use Pentium timestamp counter to mark certain events:

inst0 -- beginning of switch statement for opcode dispatch

inst1 -- end of switch statement (may be skipped)

loop0 -- the top of the mainloop

loop1 -- place where control returns again to top of mainloop

(may be skipped)

intr1 -- beginning of long interruption

intr2 -- end of long interruption

Many opcodes call out to helper C functions. In some cases, the

time in those functions should be counted towards the time for the

opcode, but not in all cases. For example, a CALL_FUNCTION opcode

calls another Python function; there's no point in charge all the

bytecode executed by the called function to the caller.

It's hard to make a useful judgement statically. In the presence

of operator overloading, it's impossible to tell if a call will

execute new Python code or not.

It's a case-by-case judgement. I'll use intr1 for the following

cases:

IMPORT_STAR

IMPORT_FROM

CALL_FUNCTION (and friends)

*/

uint64 inst0, inst1, loop0, loop1, intr0 = 0, intr1 = 0;

int ticked = 0;

READ_TIMESTAMP(inst0);

READ_TIMESTAMP(inst1);

READ_TIMESTAMP(loop0);

READ_TIMESTAMP(loop1);

/* shut up the compiler */

opcode = 0;

#endif

/* Code access macros */

#define INSTR_OFFSET() ((int)(next_instr - first_instr))

#define NEXTOP() (*next_instr++)

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

#define PEEKARG() ((next_instr[2]<<8) + next_instr[1])

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

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

/* OpCode prediction macros

Some opcodes tend to come in pairs thus making it possible to

predict the second code when the first is run. For example,

COMPARE_OP is often followed by JUMP_IF_FALSE or JUMP_IF_TRUE. And,

those opcodes are often followed by a POP_TOP.

Verifying the prediction costs a single high-speed test of register

variable against a constant. If the pairing was good, then the

processor has a high likelihood of making its own successful branch

prediction which results in a nearly zero overhead transition to the

next opcode.

A successful prediction saves a trip through the eval-loop including

its two unpredictable branches, the HASARG test and the switch-case.

If collecting opcode statistics, turn off prediction so that

statistics are accurately maintained (the predictions bypass

the opcode frequency counter updates).

*/

#ifdef DYNAMIC_EXECUTION_PROFILE

#define PREDICT(op) if (0) goto PRED_##op

#else

#define PREDICT(op) if (*next_instr == op) goto PRED_##op

#endif

#define PREDICTED(op) PRED_##op: next_instr++

#define PREDICTED_WITH_ARG(op) PRED_##op: oparg = PEEKARG(); next_instr += 3

/* Stack manipulation macros */

/* The stack can grow at most MAXINT deep, as co_nlocals and

co_stacksize are ints. */

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

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

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

#define SECOND() (stack_pointer[-2])

#define THIRD() (stack_pointer[-3])

#define FOURTH() (stack_pointer[-4])

#define SET_TOP(v) (stack_pointer[-1] = (v))

#define SET_SECOND(v) (stack_pointer[-2] = (v))

#define SET_THIRD(v) (stack_pointer[-3] = (v))

#define SET_FOURTH(v) (stack_pointer[-4] = (v))

#define BASIC_STACKADJ(n) (stack_pointer += n)

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

#define BASIC_POP() (*--stack_pointer)

#ifdef LLTRACE

#define PUSH(v) { (void)(BASIC_PUSH(v), \

lltrace && prtrace(TOP(), "push")); \

assert(STACK_LEVEL() <= co->co_stacksize); }

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

BASIC_POP())

#define STACKADJ(n) { (void)(BASIC_STACKADJ(n), \

lltrace && prtrace(TOP(), "stackadj")); \

assert(STACK_LEVEL() <= co->co_stacksize); }

#define EXT_POP(STACK_POINTER) (lltrace && prtrace((STACK_POINTER)[-1], \

"ext_pop"), *--(STACK_POINTER))

#else

#define PUSH(v) BASIC_PUSH(v)

#define POP() BASIC_POP()

#define STACKADJ(n) BASIC_STACKADJ(n)

#define EXT_POP(STACK_POINTER) (*--(STACK_POINTER))

#endif

/* Local variable macros */

#define GETLOCAL(i) (fastlocals[i])

/* The SETLOCAL() macro must not DECREF the local variable in-place and

then store the new value; it must copy the old value to a temporary

value, then store the new value, and then DECREF the temporary value.

This is because it is possible that during the DECREF the frame is

accessed by other code (e.g. a __del__ method or gc.collect()) and the

variable would be pointing to already-freed memory. */

#define SETLOCAL(i, value) do { PyObject *tmp = GETLOCAL(i); \

GETLOCAL(i) = value; \

Py_XDECREF(tmp); } while (0)

/* Start of code */

if (f == NULL)

return NULL;

/* push frame */

if (Py_EnterRecursiveCall(""))

return NULL;

tstate->frame = f;

if (tstate->use_tracing) {

if (tstate->c_tracefunc != NULL) {

/* tstate->c_tracefunc, 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 is also called

whenever an exception is detected. */

if (call_trace_protected(tstate->c_tracefunc,

tstate->c_traceobj,

f, PyTrace_CALL, Py_None)) {

/* Trace function raised an error */

goto exit_eval_frame;

}

}

if (tstate->c_profilefunc != NULL) {

/* Similar for c_profilefunc, except it needn't

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

if (call_trace_protected(tstate->c_profilefunc,

tstate->c_profileobj,

f, PyTrace_CALL, Py_None)) {

/* Profile function raised an error */

goto exit_eval_frame;

}

}

}

co = f->f_code;

names = co->co_names;

consts = co->co_consts;

fastlocals = f->f_localsplus;

freevars = f->f_localsplus + co->co_nlocals;

first_instr = (unsigned char*) PyString_AS_STRING(co->co_code);

/* An explanation is in order for the next line.

f->f_lasti now refers to the index of the last instruction

executed. You might think this was obvious from the name, but

this wasn't always true before 2.3! PyFrame_New now sets

f->f_lasti to -1 (i.e. the index *before* the first instruction)

and YIELD_VALUE doesn't fiddle with f_lasti any more. So this

does work. Promise.

When the PREDICT() macros are enabled, some opcode pairs follow in

direct succession without updating f->f_lasti. A successful

prediction effectively links the two codes together as if they

were a single new opcode; accordingly,f->f_lasti will point to

the first code in the pair (for instance, GET_ITER followed by

FOR_ITER is effectively a single opcode and f->f_lasti will point

at to the beginning of the combined pair.)

*/

next_instr = first_instr + f->f_lasti + 1;

stack_pointer = f->f_stacktop;

assert(stack_pointer != NULL);

f->f_stacktop = NULL; /* remains NULL unless yield suspends frame */

#ifdef LLTRACE

lltrace = PyDict_GetItemString(f->f_globals, "__lltrace__") != NULL;

#endif

#if defined(Py_DEBUG) || defined(LLTRACE)

filename = PyUnicode_AsString(co->co_filename);

#endif

why = WHY_NOT;

err = 0;

x = Py_None; /* Not a reference, just anything non-NULL */

w = NULL;

if (throwflag) { /* support for generator.throw() */

why = WHY_EXCEPTION;

goto on_error;

}

for (;;) {

#ifdef WITH_TSC

if (inst1 == 0) {

/* Almost surely, the opcode executed a break

or a continue, preventing inst1 from being set

on the way out of the loop.

*/

READ_TIMESTAMP(inst1);

loop1 = inst1;

}

dump_tsc(opcode, ticked, inst0, inst1, loop0, loop1,

intr0, intr1);

ticked = 0;

inst1 = 0;

intr0 = 0;

intr1 = 0;

READ_TIMESTAMP(loop0);

#endif

assert(stack_pointer >= f->f_valuestack); /* else underflow */

assert(STACK_LEVEL() <= co->co_stacksize); /* else overflow */

/* Do periodic things. Doing this every time through

the loop would add too much overhead, so we do it

only every Nth instruction. We also do it if

``things_to_do'' is set, i.e. when an asynchronous

event needs attention (e.g. a signal handler or

async I/O handler); see Py_AddPendingCall() and

Py_MakePendingCalls() above. */

if (--_Py_Ticker < 0) {

if (*next_instr == SETUP_FINALLY) {

/* Make the last opcode before

a try: finally: block uninterruptable. */

goto fast_next_opcode;

}

_Py_Ticker = _Py_CheckInterval;

tstate->tick_counter++;

#ifdef WITH_TSC

ticked = 1;

#endif

if (things_to_do) {

if (Py_MakePendingCalls() < 0) {

why = WHY_EXCEPTION;

goto on_error;

}

if (things_to_do)

/* MakePendingCalls() didn't succeed.

Force early re-execution of this

"periodic" code, possibly after

a thread switch */

_Py_Ticker = 0;

}

#ifdef WITH_THREAD

if (interpreter_lock) {

/* Give another thread a chance */

if (PyThreadState_Swap(NULL) != tstate)

Py_FatalError("ceval: tstate mix-up");

PyThread_release_lock(interpreter_lock);

/* Other threads may run now */

PyThread_acquire_lock(interpreter_lock, 1);

if (PyThreadState_Swap(tstate) != NULL)

Py_FatalError("ceval: orphan tstate");

/* Check for thread interrupts */

if (tstate->async_exc != NULL) {

x = tstate->async_exc;

tstate->async_exc = NULL;

PyErr_SetNone(x);

Py_DECREF(x);

why = WHY_EXCEPTION;

goto on_error;

}

}

#endif

}

fast_next_opcode:

f->f_lasti = INSTR_OFFSET();

/* line-by-line tracing support */

if (tstate->c_tracefunc != NULL && !tstate->tracing) {

/* see maybe_call_line_trace

for expository comments */

f->f_stacktop = stack_pointer;

err = maybe_call_line_trace(tstate->c_tracefunc,

tstate->c_traceobj,

f, &instr_lb, &instr_ub,

&instr_prev);

/* Reload possibly changed frame fields */

JUMPTO(f->f_lasti);

if (f->f_stacktop != NULL) {

stack_pointer = f->f_stacktop;

f->f_stacktop = NULL;

}

if (err) {

/* trace function raised an exception */

goto on_error;

}

}

/* Extract opcode and argument */

opcode = NEXTOP();

oparg = 0; /* allows oparg to be stored in a register because

it doesn't have to be remembered across a full loop */

if (HAS_ARG(opcode))

oparg = NEXTARG();

dispatch_opcode:

#ifdef DYNAMIC_EXECUTION_PROFILE

#ifdef DXPAIRS

dxpairs[lastopcode][opcode]++;

lastopcode = opcode;

#endif

dxp[opcode]++;

#endif

#ifdef LLTRACE

/* Instruction tracing */

if (lltrace) {

if (HAS_ARG(opcode)) {

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

f->f_lasti, opcode, oparg);

}

else {

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

f->f_lasti, opcode);

}

}

#endif

/* Main switch on opcode */

READ_TIMESTAMP(inst0);

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 NOP:

goto fast_next_opcode;

case LOAD_FAST:

x = GETLOCAL(oparg);

if (x != NULL) {

Py_INCREF(x);

PUSH(x);

goto fast_next_opcode;

}

format_exc_check_arg(PyExc_UnboundLocalError,

UNBOUNDLOCAL_ERROR_MSG,

PyTuple_GetItem(co->co_varnames, oparg));

break;

case LOAD_CONST:

x = GETITEM(consts, oparg);

Py_INCREF(x);

PUSH(x);

goto fast_next_opcode;

PREDICTED_WITH_ARG(STORE_FAST);

case STORE_FAST:

v = POP();

SETLOCAL(oparg, v);

goto fast_next_opcode;

PREDICTED(POP_TOP);

case POP_TOP:

v = POP();

Py_DECREF(v);

goto fast_next_opcode;

case ROT_TWO:

v = TOP();

w = SECOND();

SET_TOP(w);

SET_SECOND(v);

goto fast_next_opcode;

case ROT_THREE:

v = TOP();

w = SECOND();

x = THIRD();

SET_TOP(w);

SET_SECOND(x);

SET_THIRD(v);

goto fast_next_opcode;

case ROT_FOUR:

u = TOP();

v = SECOND();

w = THIRD();

x = FOURTH();

SET_TOP(v);

SET_SECOND(w);

SET_THIRD(x);

SET_FOURTH(u);

goto fast_next_opcode;

case DUP_TOP:

v = TOP();

Py_INCREF(v);

PUSH(v);

goto fast_next_opcode;

case DUP_TOPX:

if (oparg == 2) {