bpo-26110: Add CALL_METHOD_KW opcode to speedup method calls with keywords

Lib/importlib/_bootstrap_external.py

@@ -353,6 +353,7 @@ def _write_atomic(path, data, mode=0o666):
 #     Python 3.10b1 3438 Safer line number table handling.
 #     Python 3.10b1 3439 (Add ROT_N)
 #     Python 3.11a1 3450 Use exception table for unwinding ("zero cost" exception handling)
+#     Python 3.11a1 3451 (Add CALL_METHOD_KW)
 
 #
 # MAGIC must change whenever the bytecode emitted by the compiler may no
@@ -362,7 +363,7 @@ def _write_atomic(path, data, mode=0o666):
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3450).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3451).to_bytes(2, 'little') + b'\r\n'
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 
 _PYCACHE = '__pycache__'

Lib/opcode.py

@@ -213,5 +213,6 @@ def jabs_op(name, op):
 def_op('SET_UPDATE', 163)
 def_op('DICT_MERGE', 164)
 def_op('DICT_UPDATE', 165)
+def_op('CALL_METHOD_KW', 166)
 
 del def_op, name_op, jrel_op, jabs_op

Misc/NEWS.d/next/Core and Builtins/2021-05-10-18-49-13.bpo-26110.EQzqqA.rst

@@ -0,0 +1,3 @@
+Add ``CALL_METHOD_KW`` opcode to speed up method calls with keyword
+arguments.  Idea originated from PyPy.  A side effect is executing
+``CALL_METHOD`` is now branchless in the evaluation loop.

Python/ceval.c

@@ -4164,54 +4164,71 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
 
         case TARGET(CALL_METHOD): {
             /* Designed to work in tamdem with LOAD_METHOD. */
-            PyObject **sp, *res, *meth;
+            PyObject **sp, *res;
+            PyObject *names = NULL;
+            int meth_found;
 
             sp = stack_pointer;
+            /* `meth` is NULL when LOAD_METHOD thinks that it's not
+                a method call.
 
-            meth = PEEK(oparg + 2);
-            if (meth == NULL) {
-                /* `meth` is NULL when LOAD_METHOD thinks that it's not
-                   a method call.
-
-                   Stack layout:
+                Stack layout:
 
                        ... | NULL | callable | arg1 | ... | argN
                                                             ^- TOP()
                                                ^- (-oparg)
                                     ^- (-oparg-1)
                              ^- (-oparg-2)
 
-                   `callable` will be POPed by call_function.
-                   NULL will will be POPed manually later.
-                */
-                res = call_function(tstate, &trace_info, &sp, oparg, NULL);
-                stack_pointer = sp;
-                (void)POP(); /* POP the NULL. */
-            }
-            else {
-                /* This is a method call.  Stack layout:
+                `callable` will be POPed by call_function.
+                NULL will will be POPed manually later.
+                If `meth` isn't NULL, it's a method call.  Stack layout:
 
                      ... | method | self | arg1 | ... | argN
                                                         ^- TOP()
                                            ^- (-oparg)
                                     ^- (-oparg-1)
                            ^- (-oparg-2)
 
-                  `self` and `method` will be POPed by call_function.
-                  We'll be passing `oparg + 1` to call_function, to
-                  make it accept the `self` as a first argument.
-                */
-                res = call_function(tstate, &trace_info, &sp, oparg + 1, NULL);
-                stack_pointer = sp;
-            }
+               `self` and `method` will be POPed by call_function.
+               We'll be passing `oparg + 1` to call_function, to
+               make it accept the `self` as a first argument.
+            */
+            meth_found = (PEEK(oparg + 2) != NULL);
+            res = call_function(tstate, &trace_info, &sp, oparg + meth_found, NULL);
+            stack_pointer = sp;
 
+            STACK_SHRINK((1 - meth_found));
             PUSH(res);
-            if (res == NULL)
+            if (res == NULL) {
                 goto error;
+            }
             CHECK_EVAL_BREAKER();
             DISPATCH();
         }
+        case TARGET(CALL_METHOD_KW): {
+            /* Designed to work in tandem with LOAD_METHOD. Same as CALL_METHOD
+            but pops TOS to get a tuple of keyword names. */
+            PyObject **sp, *res;
+            PyObject *names = NULL;
+            int meth_found;
 
+            names = POP();
+
+            sp = stack_pointer;
+            meth_found = (PEEK(oparg + 2) != NULL);
+            res = call_function(tstate, &trace_info, &sp, oparg + meth_found, names);
+            stack_pointer = sp;
+
+            STACK_SHRINK((1 - meth_found));
+            PUSH(res);
+            Py_DECREF(names);
+            if (res == NULL) {
+                goto error;
+            }
+            CHECK_EVAL_BREAKER();
+            DISPATCH();
+        }
         case TARGET(CALL_FUNCTION): {
             PREDICTED(CALL_FUNCTION);
             PyObject **sp, *res;

Python/compile.c

@@ -309,6 +309,10 @@ static int are_all_items_const(asdl_expr_seq *, Py_ssize_t, Py_ssize_t);
 static int compiler_with(struct compiler *, stmt_ty, int);
 static int compiler_async_with(struct compiler *, stmt_ty, int);
 static int compiler_async_for(struct compiler *, stmt_ty);
+static int validate_keywords(struct compiler *c, asdl_keyword_seq *keywords);
+static int compiler_call_simple_kw_helper(struct compiler *c,
+                                          asdl_keyword_seq *keywords,
+                                          Py_ssize_t nkwelts);
 static int compiler_call_helper(struct compiler *c, int n,
                                 asdl_expr_seq *args,
                                 asdl_keyword_seq *keywords);
@@ -1176,6 +1180,8 @@ stack_effect(int opcode, int oparg, int jump)
             return -oparg;
         case CALL_METHOD:
             return -oparg-1;
+        case CALL_METHOD_KW:
+            return -oparg-2;
         case CALL_FUNCTION_KW:
             return -oparg-1;
         case CALL_FUNCTION_EX:
@@ -4266,19 +4272,19 @@ check_index(struct compiler *c, expr_ty e, expr_ty s)
 static int
 maybe_optimize_method_call(struct compiler *c, expr_ty e)
 {
-    Py_ssize_t argsl, i;
+    Py_ssize_t argsl, i, kwdsl;
     expr_ty meth = e->v.Call.func;
     asdl_expr_seq *args = e->v.Call.args;
+    asdl_keyword_seq *kwds = e->v.Call.keywords;
 
-    /* Check that the call node is an attribute access, and that
-       the call doesn't have keyword parameters. */
-    if (meth->kind != Attribute_kind || meth->v.Attribute.ctx != Load ||
-            asdl_seq_LEN(e->v.Call.keywords)) {
+    /* Check that the call node is an attribute access */
+    if (meth->kind != Attribute_kind || meth->v.Attribute.ctx != Load) {
         return -1;
     }
     /* Check that there aren't too many arguments */
     argsl = asdl_seq_LEN(args);
-    if (argsl >= STACK_USE_GUIDELINE) {
+    kwdsl = asdl_seq_LEN(kwds);
+    if (argsl + kwdsl + (kwdsl != 0) >= STACK_USE_GUIDELINE) {
         return -1;
     }
     /* Check that there are no *varargs types of arguments. */
@@ -4289,13 +4295,28 @@ maybe_optimize_method_call(struct compiler *c, expr_ty e)
         }
     }
 
+    for (i = 0; i < kwdsl; i++) {
+        keyword_ty kw = asdl_seq_GET(kwds, i);
+        if (kw->arg == NULL) {
+            return -1;
+        }
+    }
     /* Alright, we can optimize the code. */
     VISIT(c, expr, meth->v.Attribute.value);
     int old_lineno = c->u->u_lineno;
     c->u->u_lineno = meth->end_lineno;
     ADDOP_NAME(c, LOAD_METHOD, meth->v.Attribute.attr, names);
     VISIT_SEQ(c, expr, e->v.Call.args);
-    ADDOP_I(c, CALL_METHOD, asdl_seq_LEN(e->v.Call.args));
+
+    if (kwdsl) {
+        if (!compiler_call_simple_kw_helper(c, kwds, kwdsl)) {
+            return 0;
+        };
+        ADDOP_I(c, CALL_METHOD_KW, argsl + kwdsl);
+    }
+    else {
+        ADDOP_I(c, CALL_METHOD, argsl);    
+    }
     c->u->u_lineno = old_lineno;
     return 1;
 }
@@ -4327,6 +4348,9 @@ validate_keywords(struct compiler *c, asdl_keyword_seq *keywords)
 static int
 compiler_call(struct compiler *c, expr_ty e)
 {
+    if (validate_keywords(c, e->v.Call.keywords) == -1) {
+        return 0;
+    }
     int ret = maybe_optimize_method_call(c, e);
     if (ret >= 0) {
         return ret;
@@ -4458,6 +4482,36 @@ compiler_subkwargs(struct compiler *c, asdl_keyword_seq *keywords, Py_ssize_t be
     return 1;
 }
 
+/* Used by compiler_call_helper and maybe_optimize_method_call to emit 
+LOAD_CONST kw1
+LOAD_CONST kw2
+...
+LOAD_CONST <tuple of kwnames>
+before a CALL_(FUNCTION|METHOD)_KW.
+
+Returns 1 on success, 0 on error.
+*/
+static int
+compiler_call_simple_kw_helper(struct compiler *c,
+                               asdl_keyword_seq *keywords, 
+                               Py_ssize_t nkwelts)
+{
+    PyObject *names;
+    VISIT_SEQ(c, keyword, keywords);
+    names = PyTuple_New(nkwelts);
+    if (names == NULL) {
+        return 0;
+    }
+    for (int i = 0; i < nkwelts; i++) {
+        keyword_ty kw = asdl_seq_GET(keywords, i);
+        Py_INCREF(kw->arg);
+        PyTuple_SET_ITEM(names, i, kw->arg);
+    }
+    ADDOP_LOAD_CONST_NEW(c, names);
+    return 1;
+}
+
+
 /* shared code between compiler_call and compiler_class */
 static int
 compiler_call_helper(struct compiler *c,
@@ -4497,18 +4551,9 @@ compiler_call_helper(struct compiler *c,
         VISIT(c, expr, elt);
     }
     if (nkwelts) {
-        PyObject *names;
-        VISIT_SEQ(c, keyword, keywords);
-        names = PyTuple_New(nkwelts);
-        if (names == NULL) {
+        if (!compiler_call_simple_kw_helper(c, keywords, nkwelts)) {
             return 0;
-        }
-        for (i = 0; i < nkwelts; i++) {
-            keyword_ty kw = asdl_seq_GET(keywords, i);
-            Py_INCREF(kw->arg);
-            PyTuple_SET_ITEM(names, i, kw->arg);
-        }
-        ADDOP_LOAD_CONST_NEW(c, names);
+        };
         ADDOP_I(c, CALL_FUNCTION_KW, n + nelts + nkwelts);
         return 1;
     }