bpo-39156: Break up COMPARE_OP into four logically distinct opcodes. (GH-17754)

Break up COMPARE_OP into four logically distinct opcodes:
* COMPARE_OP for rich comparisons
* IS_OP for 'is' and 'is not' tests
* CONTAINS_OP for 'in' and 'is not' tests
* JUMP_IF_NOT_EXC_MATCH for checking exceptions in 'try-except' statements.

1 files changed, 78 insertions, 59 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index e8931c8882..096645aeeb 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -67,7 +67,6 @@ static void maybe_dtrace_line(PyFrameObject *, int *, int *, int *);
 static void dtrace_function_entry(PyFrameObject *);
 static void dtrace_function_return(PyFrameObject *);
 
-static PyObject * cmp_outcome(PyThreadState *, int, PyObject *, PyObject *);
 static PyObject * import_name(PyThreadState *, PyFrameObject *,
                               PyObject *, PyObject *, PyObject *);
 static PyObject * import_from(PyThreadState *, PyObject *, PyObject *);
@@ -2897,12 +2896,13 @@ main_loop:
         }
 
         case TARGET(COMPARE_OP): {
+            assert(oparg <= Py_GE);
             PyObject *right = POP();
             PyObject *left = TOP();
-            PyObject *res = cmp_outcome(tstate, oparg, left, right);
+            PyObject *res = PyObject_RichCompare(left, right, oparg);
+            SET_TOP(res);
             Py_DECREF(left);
             Py_DECREF(right);
-            SET_TOP(res);
             if (res == NULL)
                 goto error;
             PREDICT(POP_JUMP_IF_FALSE);
@@ -2910,6 +2910,81 @@ main_loop:
             DISPATCH();
         }
 
+        case TARGET(IS_OP): {
+            PyObject *right = POP();
+            PyObject *left = TOP();
+            int res = (left == right)^oparg;
+            PyObject *b = res ? Py_True : Py_False;
+            Py_INCREF(b);
+            SET_TOP(b);
+            Py_DECREF(left);
+            Py_DECREF(right);
+            PREDICT(POP_JUMP_IF_FALSE);
+            PREDICT(POP_JUMP_IF_TRUE);
+            FAST_DISPATCH();
+        }
+
+        case TARGET(CONTAINS_OP): {
+            PyObject *right = POP();
+            PyObject *left = POP();
+            int res = PySequence_Contains(right, left);
+            Py_DECREF(left);
+            Py_DECREF(right);
+            if (res < 0) {
+                goto error;
+            }
+            PyObject *b = (res^oparg) ? Py_True : Py_False;
+            Py_INCREF(b);
+            PUSH(b);
+            PREDICT(POP_JUMP_IF_FALSE);
+            PREDICT(POP_JUMP_IF_TRUE);
+            FAST_DISPATCH();
+        }
+
+#define CANNOT_CATCH_MSG "catching classes that do not inherit from "\
+                         "BaseException is not allowed"
+
+        case TARGET(JUMP_IF_NOT_EXC_MATCH): {
+            PyObject *right = POP();
+            PyObject *left = POP();
+            if (PyTuple_Check(right)) {
+                Py_ssize_t i, length;
+                length = PyTuple_GET_SIZE(right);
+                for (i = 0; i < length; i++) {
+                    PyObject *exc = PyTuple_GET_ITEM(right, i);
+                    if (!PyExceptionClass_Check(exc)) {
+                        _PyErr_SetString(tstate, PyExc_TypeError,
+                                        CANNOT_CATCH_MSG);
+                        Py_DECREF(left);
+                        Py_DECREF(right);
+                        goto error;
+                    }
+                }
+            }
+            else {
+                if (!PyExceptionClass_Check(right)) {
+                    _PyErr_SetString(tstate, PyExc_TypeError,
+                                    CANNOT_CATCH_MSG);
+                    Py_DECREF(left);
+                    Py_DECREF(right);
+                    goto error;
+                }
+            }
+            int res = PyErr_GivenExceptionMatches(left, right);
+            Py_DECREF(left);
+            Py_DECREF(right);
+            if (res > 0) {
+                /* Exception matches -- Do nothing */;
+            }
+            else if (res == 0) {
+                JUMPTO(oparg);
+            }
+            else {
+                goto error;
+            }
+            DISPATCH();
+        }
+
         case TARGET(IMPORT_NAME): {
             PyObject *name = GETITEM(names, oparg);
             PyObject *fromlist = POP();
@@ -4951,62 +5026,6 @@ _PyEval_SliceIndexNotNone(PyObject *v, Py_ssize_t *pi)
     return 1;
 }
 
-
-#define CANNOT_CATCH_MSG "catching classes that do not inherit from "\
-                         "BaseException is not allowed"
-
-static PyObject *
-cmp_outcome(PyThreadState *tstate, int op, PyObject *v, PyObject *w)
-{
-    int res = 0;
-    switch (op) {
-    case PyCmp_IS:
-        res = (v == w);
-        break;
-    case PyCmp_IS_NOT:
-        res = (v != w);
-        break;
-    case PyCmp_IN:
-        res = PySequence_Contains(w, v);
-        if (res < 0)
-            return NULL;
-        break;
-    case PyCmp_NOT_IN:
-        res = PySequence_Contains(w, v);
-        if (res < 0)
-            return NULL;
-        res = !res;
-        break;
-    case PyCmp_EXC_MATCH:
-        if (PyTuple_Check(w)) {
-            Py_ssize_t i, length;
-            length = PyTuple_Size(w);
-            for (i = 0; i < length; i += 1) {
-                PyObject *exc = PyTuple_GET_ITEM(w, i);
-                if (!PyExceptionClass_Check(exc)) {
-                    _PyErr_SetString(tstate, PyExc_TypeError,
-                                     CANNOT_CATCH_MSG);
-                    return NULL;
-                }
-            }
-        }
-        else {
-            if (!PyExceptionClass_Check(w)) {
-                _PyErr_SetString(tstate, PyExc_TypeError,
-                                 CANNOT_CATCH_MSG);
-                return NULL;
-            }
-        }
-        res = PyErr_GivenExceptionMatches(v, w);
-        break;
-    default:
-        return PyObject_RichCompare(v, w, op);
-    }
-    v = res ? Py_True : Py_False;
-    Py_INCREF(v);
-    return v;
-}
-
 static PyObject *
 import_name(PyThreadState *tstate, PyFrameObject *f,
             PyObject *name, PyObject *fromlist, PyObject *level)