Modernize CALL (not too happy with it)

Author: gvanrossum

Python/bytecodes.c

@@ -2366,10 +2366,10 @@ dummy_func(
 
         // Cache layout: counter/1, func_version/2, min_args/1
         // Neither CALL_INTRINSIC_1 nor CALL_FUNCTION_EX are members!
-        // family(call, INLINE_CACHE_ENTRIES_CALL) = {
-        //     CALL,
-        //     CALL_BOUND_METHOD_EXACT_ARGS,
-        //     CALL_PY_EXACT_ARGS,
+        family(call, INLINE_CACHE_ENTRIES_CALL) = {
+            CALL,
+            CALL_BOUND_METHOD_EXACT_ARGS,
+            CALL_PY_EXACT_ARGS,
         //     CALL_PY_WITH_DEFAULTS,
         //     CALL_NO_KW_TYPE_1,
         //     CALL_NO_KW_STR_1,
@@ -2385,10 +2385,15 @@ dummy_func(
         //     CALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS,
         //     CALL_NO_KW_METHOD_DESCRIPTOR_NOARGS,
         //     CALL_NO_KW_METHOD_DESCRIPTOR_FAST,
-        // };
+        };
 
-        // stack effect: (__0, __array[oparg] -- )
-        inst(CALL) {
+        // Stack is either
+        // [NULL, function, arg1, arg2, ...]
+        // or
+        // [method, self, arg1, arg2, ...]
+        // (Some args may be keywords, see KW_NAMES, which sets 'kwnames'.)
+        // It will be replaced with [result].
+        inst(CALL, (unused/1, unused/2, unused/1, thing1, thing2, unused[oparg] -- unused)) {
             #if ENABLE_SPECIALIZATION
             _PyCallCache *cache = (_PyCallCache *)next_instr;
             if (ADAPTIVE_COUNTER_IS_ZERO(cache->counter)) {
@@ -2404,18 +2409,18 @@ dummy_func(
             DECREMENT_ADAPTIVE_COUNTER(cache->counter);
             #endif  /* ENABLE_SPECIALIZATION */
             int total_args, is_meth;
-            is_meth = is_method(stack_pointer, oparg);
-            PyObject *function = PEEK(oparg + 1);
+            is_meth = thing1 != NULL;
+            PyObject *function = thing2;
             if (!is_meth && Py_TYPE(function) == &PyMethod_Type) {
                 PyObject *self = ((PyMethodObject *)function)->im_self;
-                PEEK(oparg+1) = Py_NewRef(self);
+                PEEK(oparg+1) = thing2 = Py_NewRef(self);
                 PyObject *meth = ((PyMethodObject *)function)->im_func;
-                PEEK(oparg+2) = Py_NewRef(meth);
+                PEEK(oparg+2) = thing1 = Py_NewRef(meth);
                 Py_DECREF(function);
                 is_meth = 1;
             }
             total_args = oparg + is_meth;
-            function = PEEK(total_args + 1);
+            function = is_meth ? thing1 : thing2;
             int positional_args = total_args - KWNAMES_LEN();
             // Check if the call can be inlined or not
             if (Py_TYPE(function) == &PyFunction_Type &&
@@ -2424,13 +2429,14 @@ dummy_func(
             {
                 int code_flags = ((PyCodeObject*)PyFunction_GET_CODE(function))->co_flags;
                 PyObject *locals = code_flags & CO_OPTIMIZED ? NULL : Py_NewRef(PyFunction_GET_GLOBALS(function));
+                // Manipulate stack directly since we leave using DISPATCH_INLINED().
                 STACK_SHRINK(total_args);
                 _PyInterpreterFrame *new_frame = _PyEvalFramePushAndInit(
                     tstate, (PyFunctionObject *)function, locals,
                     stack_pointer, positional_args, kwnames
                 );
                 kwnames = NULL;
-                STACK_SHRINK(2-is_meth);
+                STACK_SHRINK(2 - is_meth);
                 // The frame has stolen all the arguments from the stack,
                 // so there is no need to clean them up.
                 if (new_frame == NULL) {
@@ -2443,30 +2449,32 @@ dummy_func(
             PyObject *res;
             if (cframe.use_tracing) {
                 res = trace_call_function(
-                    tstate, function, stack_pointer-total_args,
+                    tstate, function, stack_pointer - total_args,
                     positional_args, kwnames);
             }
             else {
                 res = PyObject_Vectorcall(
-                    function, stack_pointer-total_args,
+                    function, stack_pointer - total_args,
                     positional_args | PY_VECTORCALL_ARGUMENTS_OFFSET,
                     kwnames);
             }
             kwnames = NULL;
             assert((res != NULL) ^ (_PyErr_Occurred(tstate) != NULL));
             Py_DECREF(function);
+            // Manipulate stack directly since we leave using DISPATCH().
             /* Clear the stack */
             STACK_SHRINK(total_args);
             for (int i = 0; i < total_args; i++) {
                 Py_DECREF(stack_pointer[i]);
             }
-            STACK_SHRINK(2-is_meth);
+            STACK_SHRINK(2 - is_meth);
             PUSH(res);
             if (res == NULL) {
                 goto error;
             }
             JUMPBY(INLINE_CACHE_ENTRIES_CALL);
             CHECK_EVAL_BREAKER();
+            DISPATCH();  // Prevents generator emitting the epologue.
         }
 
         // Start out with [NULL, method, arg1, arg2, ...]

Python/generated_cases.c.h

@@ -287,7 +287,7 @@ _PyOpcode_num_popped(int opcode, int oparg, bool jump) {
         case KW_NAMES:
             return 0;
         case CALL:
-            return -1;
+            return oparg + 2;
         case CALL_BOUND_METHOD_EXACT_ARGS:
             return oparg + 2;
         case CALL_PY_EXACT_ARGS:
@@ -633,7 +633,7 @@ _PyOpcode_num_pushed(int opcode, int oparg, bool jump) {
         case KW_NAMES:
             return 0;
         case CALL:
-            return -1;
+            return 1;
         case CALL_BOUND_METHOD_EXACT_ARGS:
             return 1;
         case CALL_PY_EXACT_ARGS:
@@ -842,7 +842,7 @@ struct opcode_metadata {
     [LOAD_ATTR_METHOD_NO_DICT] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC00000000 },
     [LOAD_ATTR_METHOD_LAZY_DICT] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC00000000 },
     [KW_NAMES] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
-    [CALL] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },
+    [CALL] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC000 },
     [CALL_BOUND_METHOD_EXACT_ARGS] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC000 },
     [CALL_PY_EXACT_ARGS] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IBC000 },
     [CALL_PY_WITH_DEFAULTS] = { DIR_NONE, DIR_NONE, DIR_NONE, true, INSTR_FMT_IB },