bpo-39984: Add PyInterpreterState.ceval (GH-19047)

subinterpreters: Move _PyRuntimeState.ceval.tracing_possible to
PyInterpreterState.ceval.tracing_possible: each interpreter now has
its own variable.

Changes:

* Add _ceval_state structure.
* Add PyInterpreterState.ceval field.
* _PyEval_EvalFrameDefault(): add ceval2 variable (struct _ceval_state*).
* Rename _PyEval_Initialize() to _PyEval_InitRuntimeState().
* Add _PyEval_InitState().
* Don't export internal _Py_FinishPendingCalls() and
  _PyEval_FiniThreads() functions anymore.

Include/internal/pycore_ceval.h

@@ -15,9 +15,10 @@ struct _frame;
 
 #include "pycore_pystate.h"   /* PyInterpreterState.eval_frame */
 
-PyAPI_FUNC(void) _Py_FinishPendingCalls(PyThreadState *tstate);
+extern void _Py_FinishPendingCalls(PyThreadState *tstate);
-PyAPI_FUNC(void) _PyEval_Initialize(struct _ceval_runtime_state *);
+extern void _PyEval_InitRuntimeState(struct _ceval_runtime_state *);
-PyAPI_FUNC(void) _PyEval_FiniThreads(
+extern void _PyEval_InitState(struct _ceval_state *);
+extern void _PyEval_FiniThreads(
     struct _ceval_runtime_state *ceval);
 PyAPI_FUNC(void) _PyEval_SignalReceived(
     struct _ceval_runtime_state *ceval);

Include/internal/pycore_pystate.h

@@ -35,12 +35,6 @@ struct _pending_calls {
 
 struct _ceval_runtime_state {
     int recursion_limit;
-    /* Records whether tracing is on for any thread.  Counts the number
-       of threads for which tstate->c_tracefunc is non-NULL, so if the
-       value is 0, we know we don't have to check this thread's
-       c_tracefunc.  This speeds up the if statement in
-       PyEval_EvalFrameEx() after fast_next_opcode. */
-    int tracing_possible;
     /* This single variable consolidates all requests to break out of
        the fast path in the eval loop. */
     _Py_atomic_int eval_breaker;
@@ -52,6 +46,15 @@ struct _ceval_runtime_state {
     struct _gil_runtime_state gil;
 };
 
+struct _ceval_state {
+    /* Records whether tracing is on for any thread.  Counts the number
+       of threads for which tstate->c_tracefunc is non-NULL, so if the
+       value is 0, we know we don't have to check this thread's
+       c_tracefunc.  This speeds up the if statement in
+       _PyEval_EvalFrameDefault() after fast_next_opcode. */
+    int tracing_possible;
+};
+
 /* interpreter state */
 
 #define _PY_NSMALLPOSINTS           257
@@ -75,6 +78,7 @@ struct _is {
 
     int finalizing;
 
+    struct _ceval_state ceval;
     struct _gc_runtime_state gc;
 
     PyObject *modules;

Misc/NEWS.d/next/Core and Builtins/2020-03-17-01-55-33.bpo-39984.y5Chgb.rst

@@ -0,0 +1,3 @@
+subinterpreters: Move ``_PyRuntimeState.ceval.tracing_possible`` to
+``PyInterpreterState.ceval.tracing_possible``: each interpreter now has its own
+variable.

Python/ceval.c

@@ -638,11 +638,17 @@ Py_MakePendingCalls(void)
 int _Py_CheckRecursionLimit = Py_DEFAULT_RECURSION_LIMIT;
 
 void
-_PyEval_Initialize(struct _ceval_runtime_state *state)
+_PyEval_InitRuntimeState(struct _ceval_runtime_state *ceval)
 {
-    state->recursion_limit = Py_DEFAULT_RECURSION_LIMIT;
+    ceval->recursion_limit = Py_DEFAULT_RECURSION_LIMIT;
     _Py_CheckRecursionLimit = Py_DEFAULT_RECURSION_LIMIT;
-    _gil_initialize(&state->gil);
+    _gil_initialize(&ceval->gil);
+}
+
+void
+_PyEval_InitState(struct _ceval_state *ceval)
+{
+    /* PyInterpreterState_New() initializes ceval to zero */
 }
 
 int
@@ -657,7 +663,7 @@ Py_SetRecursionLimit(int new_limit)
 {
     struct _ceval_runtime_state *ceval = &_PyRuntime.ceval;
     ceval->recursion_limit = new_limit;
-    _Py_CheckRecursionLimit = ceval->recursion_limit;
+    _Py_CheckRecursionLimit = new_limit;
 }
 
 /* The function _Py_EnterRecursiveCall() only calls _Py_CheckRecursiveCall()
@@ -753,6 +759,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
     PyObject *retval = NULL;            /* Return value */
     _PyRuntimeState * const runtime = &_PyRuntime;
     struct _ceval_runtime_state * const ceval = &runtime->ceval;
+    struct _ceval_state * const ceval2 = &tstate->interp->ceval;
     _Py_atomic_int * const eval_breaker = &ceval->eval_breaker;
     PyCodeObject *co;
 
@@ -841,7 +848,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
 #ifdef LLTRACE
 #define FAST_DISPATCH() \
     { \
-        if (!lltrace && !_Py_TracingPossible(ceval) && !PyDTrace_LINE_ENABLED()) { \
+        if (!lltrace && !_Py_TracingPossible(ceval2) && !PyDTrace_LINE_ENABLED()) { \
             f->f_lasti = INSTR_OFFSET(); \
             NEXTOPARG(); \
             goto *opcode_targets[opcode]; \
@@ -851,7 +858,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
 #else
 #define FAST_DISPATCH() \
     { \
-        if (!_Py_TracingPossible(ceval) && !PyDTrace_LINE_ENABLED()) { \
+        if (!_Py_TracingPossible(ceval2) && !PyDTrace_LINE_ENABLED()) { \
             f->f_lasti = INSTR_OFFSET(); \
             NEXTOPARG(); \
             goto *opcode_targets[opcode]; \
@@ -1268,7 +1275,7 @@ main_loop:
 
         /* line-by-line tracing support */
 
-        if (_Py_TracingPossible(ceval) &&
+        if (_Py_TracingPossible(ceval2) &&
             tstate->c_tracefunc != NULL && !tstate->tracing) {
             int err;
             /* see maybe_call_line_trace
@@ -3647,7 +3654,7 @@ exception_unwind:
                 PUSH(val);
                 PUSH(exc);
                 JUMPTO(handler);
-                if (_Py_TracingPossible(ceval)) {
+                if (_Py_TracingPossible(ceval2)) {
                     int needs_new_execution_window = (f->f_lasti < instr_lb || f->f_lasti >= instr_ub);
                     int needs_line_update = (f->f_lasti == instr_lb || f->f_lasti < instr_prev);
                     /* Make sure that we trace line after exception if we are in a new execution
@@ -4639,7 +4646,7 @@ _PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
         return -1;
     }
 
-    struct _ceval_runtime_state *ceval = &tstate->interp->runtime->ceval;
+    struct _ceval_state *ceval = &tstate->interp->ceval;
     PyObject *traceobj = tstate->c_traceobj;
     ceval->tracing_possible += (func != NULL) - (tstate->c_tracefunc != NULL);
 

Python/pystate.c

@@ -58,7 +58,7 @@ _PyRuntimeState_Init_impl(_PyRuntimeState *runtime)
     runtime->open_code_userdata = open_code_userdata;
     runtime->audit_hook_head = audit_hook_head;
 
-    _PyEval_Initialize(&runtime->ceval);
+    _PyEval_InitRuntimeState(&runtime->ceval);
 
     PyPreConfig_InitPythonConfig(&runtime->preconfig);
 
@@ -213,6 +213,7 @@ PyInterpreterState_New(void)
     _PyRuntimeState *runtime = &_PyRuntime;
     interp->runtime = runtime;
 
+    _PyEval_InitState(&interp->ceval);
     _PyGC_InitState(&interp->gc);
     PyConfig_InitPythonConfig(&interp->config);