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bpo-31370: Remove support for threads-less builds (#3385)

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* Remove Setup.config
* Always define WITH_THREAD for compatibility.
This commit is contained in:
Antoine Pitrou 2017-09-07 18:56:24 +02:00 • committed by Victor Stinner
parent 1f06a680de
commit a6a4dc816d
135 changed files with 2472 additions and 4377 deletions
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124
Python/ceval.c
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@ -87,11 +87,7 @@ static long dxp[256];
#endif
#endif
#ifdef WITH_THREAD
#define GIL_REQUEST _Py_atomic_load_relaxed(&gil_drop_request)
#else
#define GIL_REQUEST 0
#endif
/* This can set eval_breaker to 0 even though gil_drop_request became
1. We believe this is all right because the eval loop will release
@ -103,8 +99,6 @@ static long dxp[256];
_Py_atomic_load_relaxed(&pendingcalls_to_do) | \
pending_async_exc)
#ifdef WITH_THREAD
#define SET_GIL_DROP_REQUEST() \
do { \
_Py_atomic_store_relaxed(&gil_drop_request, 1); \
@ -117,8 +111,6 @@ static long dxp[256];
COMPUTE_EVAL_BREAKER(); \
} while (0)
#endif
/* Pending calls are only modified under pending_lock */
#define SIGNAL_PENDING_CALLS() \
do { \
@ -151,8 +143,6 @@ static _Py_atomic_int pendingcalls_to_do = {0};
Guarded by the GIL. */
static int pending_async_exc = 0;
#ifdef WITH_THREAD
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
@ -256,8 +246,6 @@ PyEval_ReInitThreads(void)
_PyThreadState_DeleteExcept(current_tstate);
}
#endif /* WITH_THREAD */
/* This function is used to signal that async exceptions are waiting to be
raised, therefore it is also useful in non-threaded builds. */
@ -277,10 +265,8 @@ PyEval_SaveThread(void)
PyThreadState *tstate = PyThreadState_Swap(NULL);
if (tstate == NULL)
Py_FatalError("PyEval_SaveThread: NULL tstate");
#ifdef WITH_THREAD
if (gil_created())
drop_gil(tstate);
#endif
return tstate;
}
@ -289,7 +275,6 @@ PyEval_RestoreThread(PyThreadState *tstate)
{
if (tstate == NULL)
Py_FatalError("PyEval_RestoreThread: NULL tstate");
#ifdef WITH_THREAD
if (gil_created()) {
int err = errno;
take_gil(tstate);
@ -301,7 +286,6 @@ PyEval_RestoreThread(PyThreadState *tstate)
}
errno = err;
}
#endif
PyThreadState_Swap(tstate);
}
@ -320,14 +304,12 @@ PyEval_RestoreThread(PyThreadState *tstate)
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.
There is no facility to schedule calls to a particular thread, but
that should be easy to change, should that ever be required. In
that case, the static variables here should go into the python
threadstate.
#endif
*/
void
@ -339,9 +321,7 @@ _PyEval_SignalReceived(void)
SIGNAL_PENDING_CALLS();
}
#ifdef WITH_THREAD
/* The WITH_THREAD implementation is thread-safe. It allows
/* This implementation is thread-safe. It allows
scheduling to be made from any thread, and even from an executing
callback.
*/
@ -464,106 +444,6 @@ error:
return -1;
}
#else /* if ! defined WITH_THREAD */
/*
WARNING! ASYNCHRONOUSLY EXECUTING CODE!
This code is used for signal handling in python that isn't built
with WITH_THREAD.
Don't use this implementation when Py_AddPendingCalls() can happen
on a different thread!
There are two possible race conditions:
(1) nested asynchronous calls to Py_AddPendingCall()
(2) AddPendingCall() calls made while pending calls are being processed.
(1) is very unlikely because typically signal delivery
is blocked during signal handling. So it should be impossible.
(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 is present, interrupted by signals, and that the critical
section is protected with the "busy" variable. On Windows, which
delivers SIGINT on a system thread, this does not hold and therefore
Windows really shouldn't use this version.
The two threads could theoretically wiggle around the "busy" variable.
*/
#define NPENDINGCALLS 32
static struct {
int (*func)(void *);
void *arg;
} pendingcalls[NPENDINGCALLS];
static volatile int pendingfirst = 0;
static volatile int pendinglast = 0;
int
Py_AddPendingCall(int (*func)(void *), void *arg)
{
static volatile int busy = 0;
int i, j;
/* XXX Begin critical section */
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;
SIGNAL_PENDING_CALLS();
busy = 0;
/* XXX End critical section */
return 0;
}
int
Py_MakePendingCalls(void)
{
static int busy = 0;
if (busy)
return 0;
busy = 1;
/* unsignal before starting to call callbacks, so that any callback
added in-between re-signals */
UNSIGNAL_PENDING_CALLS();
/* Python signal handler doesn't really queue a callback: it only signals
that a signal was received, see _PyEval_SignalReceived(). */
if (PyErr_CheckSignals() < 0) {
goto error;
}
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) {
goto error;
}
}
busy = 0;
return 0;
error:
busy = 0;
SIGNAL_PENDING_CALLS(); /* We're not done yet */
return -1;
}
#endif /* WITH_THREAD */
/* The interpreter's recursion limit */
@ -1101,7 +981,6 @@ _PyEval_EvalFrameDefault(PyFrameObject *f, int throwflag)
if (Py_MakePendingCalls() < 0)
goto error;
}
#ifdef WITH_THREAD
if (_Py_atomic_load_relaxed(&gil_drop_request)) {
/* Give another thread a chance */
if (PyThreadState_Swap(NULL) != tstate)
@ -1121,7 +1000,6 @@ _PyEval_EvalFrameDefault(PyFrameObject *f, int throwflag)
if (PyThreadState_Swap(tstate) != NULL)
Py_FatalError("ceval: orphan tstate");
}
#endif
/* Check for asynchronous exceptions. */
if (tstate->async_exc != NULL) {
PyObject *exc = tstate->async_exc;