python · iritkatriel · Jun 17, 2023 · Jun 15, 2023 · Jun 15, 2023 · Jun 15, 2023
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
@@ -318,6 +318,12 @@ operation is being performed, so the intermediate analysis object isn't useful:
    .. versionchanged:: 3.8
       Added *jump* parameter.
 
+   .. versionchanged:: 3.13
+      If ``oparg`` is omitted (or ``None``), the stack effect is now returned
+      for ``oparg=0``. Previously this was an error for opcodes that use their
+      arg. It is also no longer an error to pass an integer ``oparg`` when
+      the ``opcode`` does not use it; the ``oparg`` in this case is ignored.
+
 
 .. _bytecodes:
 

diff --git a/Include/internal/pycore_opcode.h b/Include/internal/pycore_opcode.h
diff --git a/Include/internal/pycore_opcode_utils.h b/Include/internal/pycore_opcode_utils.h
@@ -15,10 +15,7 @@ extern "C" {
 
 #define IS_WITHIN_OPCODE_RANGE(opcode) \
         (((opcode) >= 0 && (opcode) <= MAX_REAL_OPCODE) || \
-         IS_PSEUDO_OPCODE(opcode))
-
-#define IS_JUMP_OPCODE(opcode) \
-         is_bit_set_in_table(_PyOpcode_Jump, opcode)
+         IS_PSEUDO_INSTR(opcode))
 
 #define IS_BLOCK_PUSH_OPCODE(opcode) \
         ((opcode) == SETUP_FINALLY || \
@@ -55,27 +52,6 @@ extern "C" {
          (opcode) == RAISE_VARARGS || \
          (opcode) == RERAISE)
 
-#define LOG_BITS_PER_INT 5
-#define MASK_LOW_LOG_BITS 31
-
-static inline int
-is_bit_set_in_table(const uint32_t *table, int bitindex) {
-    /* Is the relevant bit set in the relevant word? */
-    /* 512 bits fit into 9 32-bits words.
-     * Word is indexed by (bitindex>>ln(size of int in bits)).
-     * Bit within word is the low bits of bitindex.
-     */
-    if (bitindex >= 0 && bitindex < 512) {
-        uint32_t word = table[bitindex >> LOG_BITS_PER_INT];
-        return (word >> (bitindex & MASK_LOW_LOG_BITS)) & 1;
-    }
-    else {
-        return 0;
-    }
-}
-
-#undef LOG_BITS_PER_INT
-#undef MASK_LOW_LOG_BITS
 
 /* Flags used in the oparg for MAKE_FUNCTION */
 #define MAKE_FUNCTION_DEFAULTS    0x01

diff --git a/Include/opcode.h b/Include/opcode.h
diff --git a/Lib/test/test__opcode.py b/Lib/test/test__opcode.py
@@ -15,20 +15,14 @@ def test_stack_effect(self):
         self.assertEqual(stack_effect(dis.opmap['BUILD_SLICE'], 1), -1)
         self.assertEqual(stack_effect(dis.opmap['BUILD_SLICE'], 3), -2)
         self.assertRaises(ValueError, stack_effect, 30000)
-        self.assertRaises(ValueError, stack_effect, dis.opmap['BUILD_SLICE'])
-        self.assertRaises(ValueError, stack_effect, dis.opmap['POP_TOP'], 0)
         # All defined opcodes
         has_arg = dis.hasarg
         for name, code in filter(lambda item: item[0] not in dis.deoptmap, dis.opmap.items()):
             if code >= opcode.MIN_INSTRUMENTED_OPCODE:
                 continue
             with self.subTest(opname=name):
-                if code not in has_arg:
-                    stack_effect(code)
-                    self.assertRaises(ValueError, stack_effect, code, 0)
-                else:
-                    stack_effect(code, 0)
-                    self.assertRaises(ValueError, stack_effect, code)
+                stack_effect(code)
+                stack_effect(code, 0)
         # All not defined opcodes
         for code in set(range(256)) - set(dis.opmap.values()):
             with self.subTest(opcode=code):

diff --git a/Misc/NEWS.d/next/Library/2023-06-17-12-13-57.gh-issue-105481.KgBH5w.rst b/Misc/NEWS.d/next/Library/2023-06-17-12-13-57.gh-issue-105481.KgBH5w.rst
@@ -0,0 +1,4 @@
+:func:`~dis.stack_effect`B no longer raises an exception if an ``oparg`` is
+provided for an ``opcode`` that doesn't use its arg, or when it is not
+provided for an ``opcode`` that does use it. In the latter case, the stack
+effect is returned or ``oparg=0``.
diff --git a/Modules/_opcode.c b/Modules/_opcode.c
@@ -27,25 +27,16 @@ _opcode_stack_effect_impl(PyObject *module, int opcode, PyObject *oparg,
                           PyObject *jump)
 /*[clinic end generated code: output=64a18f2ead954dbb input=461c9d4a44851898]*/
 {
-    int effect;
     int oparg_int = 0;
     int jump_int;
-    if (HAS_ARG(opcode)) {
-        if (oparg == Py_None) {
-            PyErr_SetString(PyExc_ValueError,
-                    "stack_effect: opcode requires oparg but oparg was not specified");
-            return -1;
-        }
+
+    if (oparg != Py_None) {
         oparg_int = (int)PyLong_AsLong(oparg);
         if ((oparg_int == -1) && PyErr_Occurred()) {
             return -1;
         }
     }
-    else if (oparg != Py_None) {
-        PyErr_SetString(PyExc_ValueError,
-                "stack_effect: opcode does not permit oparg but oparg was specified");
-        return -1;
-    }
+
     if (jump == Py_None) {
         jump_int = -1;
     }
@@ -60,11 +51,10 @@ _opcode_stack_effect_impl(PyObject *module, int opcode, PyObject *oparg,
                 "stack_effect: jump must be False, True or None");
         return -1;
     }
-    effect = PyCompile_OpcodeStackEffectWithJump(opcode, oparg_int, jump_int);
+    int effect = PyCompile_OpcodeStackEffectWithJump(opcode, oparg_int, jump_int);
     if (effect == PY_INVALID_STACK_EFFECT) {
-            PyErr_SetString(PyExc_ValueError,
-                    "invalid opcode or oparg");
-            return -1;
+        PyErr_SetString(PyExc_ValueError, "invalid opcode or oparg");
+        return -1;
     }
     return effect;
 }

@@ -339,10 +339,9 @@ static void
 write_instr(_Py_CODEUNIT *codestr, instruction *instr, int ilen)
 {
     int opcode = instr->i_opcode;
-    assert(IS_PSEUDO_OPCODE(opcode) == IS_PSEUDO_INSTR(opcode));
     assert(!IS_PSEUDO_INSTR(opcode));
     int oparg = instr->i_oparg;
-    assert(HAS_ARG(opcode) || oparg == 0);
+    assert(OPCODE_HAS_ARG(opcode) || oparg == 0);
     int caches = _PyOpcode_Caches[opcode];
     switch (ilen - caches) {
         case 4:

@@ -29,6 +29,7 @@
 #include "pycore_frame.h"
 #include "frameobject.h"          // _PyInterpreterFrame_GetLine
 #include "opcode.h"
+#include "opcode_metadata.h"
 #include "pydtrace.h"
 #include "setobject.h"
 #include "structmember.h"         // struct PyMemberDef, T_OFFSET_EX
@@ -141,7 +142,7 @@ lltrace_instruction(_PyInterpreterFrame *frame,
     const char *opname = _PyOpcode_OpName[opcode];
     assert(opname != NULL);
     int offset = (int)(next_instr - _PyCode_CODE(_PyFrame_GetCode(frame)));
-    if (HAS_ARG((int)_PyOpcode_Deopt[opcode])) {
+    if (OPCODE_HAS_ARG((int)_PyOpcode_Deopt[opcode])) {
         printf("%d: %s %d\n", offset * 2, opname, oparg);
     }
     else {
@@ -882,7 +883,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
 #if USE_COMPUTED_GOTOS
         _unknown_opcode:
 #else
-        EXTRA_CASES  // From opcode.h, a 'case' for each unused opcode
+        EXTRA_CASES  // From pycore_opcode.h, a 'case' for each unused opcode
 #endif
             /* Tell C compilers not to hold the opcode variable in the loop.
                next_instr points the current instruction without TARGET(). */

@@ -134,9 +134,8 @@ enum {
 int
 _PyCompile_InstrSize(int opcode, int oparg)
 {
-    assert(IS_PSEUDO_OPCODE(opcode) == IS_PSEUDO_INSTR(opcode));
     assert(!IS_PSEUDO_INSTR(opcode));
-    assert(HAS_ARG(opcode) || oparg == 0);
+    assert(OPCODE_HAS_ARG(opcode) || oparg == 0);
     int extended_args = (0xFFFFFF < oparg) + (0xFFFF < oparg) + (0xFF < oparg);
     int caches = _PyOpcode_Caches[opcode];
     return extended_args + 1 + caches;
@@ -248,15 +247,9 @@ instr_sequence_use_label(instr_sequence *seq, int lbl) {
 static int
 instr_sequence_addop(instr_sequence *seq, int opcode, int oparg, location loc)
 {
-    /* compare old and new opcode macros - use ! to compare as bools. */
-    assert(!HAS_ARG(opcode) == !OPCODE_HAS_ARG(opcode));
-    assert(!HAS_CONST(opcode) == !OPCODE_HAS_CONST(opcode));
-    assert(!OPCODE_HAS_JUMP(opcode) == !OPCODE_HAS_JUMP(opcode));
-
     assert(0 <= opcode && opcode <= MAX_OPCODE);
-    assert(IS_PSEUDO_OPCODE(opcode) == IS_PSEUDO_INSTR(opcode));
     assert(IS_WITHIN_OPCODE_RANGE(opcode));
-    assert(HAS_ARG(opcode) || HAS_TARGET(opcode) || oparg == 0);
+    assert(OPCODE_HAS_ARG(opcode) || HAS_TARGET(opcode) || oparg == 0);
     assert(0 <= oparg && oparg < (1 << 30));
 
     int idx = instr_sequence_next_inst(seq);
@@ -874,7 +867,7 @@ PyCompile_OpcodeStackEffect(int opcode, int oparg)
 static int
 codegen_addop_noarg(instr_sequence *seq, int opcode, location loc)
 {
-    assert(!HAS_ARG(opcode));
+    assert(!OPCODE_HAS_ARG(opcode));
     assert(!IS_ASSEMBLER_OPCODE(opcode));
     return instr_sequence_addop(seq, opcode, 0, loc);
 }
@@ -1151,7 +1144,7 @@ codegen_addop_j(instr_sequence *seq, location loc,
 }
 
 #define ADDOP_N(C, LOC, OP, O, TYPE) { \
-    assert(!HAS_CONST(OP)); /* use ADDOP_LOAD_CONST_NEW */ \
+    assert(!OPCODE_HAS_CONST(OP)); /* use ADDOP_LOAD_CONST_NEW */ \
     if (compiler_addop_o((C)->u, (LOC), (OP), (C)->u->u_metadata.u_ ## TYPE, (O)) < 0) { \
         Py_DECREF((O)); \
         return ERROR; \
@@ -7798,7 +7791,7 @@ instructions_to_instr_sequence(PyObject *instructions, instr_sequence *seq)
             goto error;
         }
         int oparg;
-        if (HAS_ARG(opcode)) {
+        if (OPCODE_HAS_ARG(opcode)) {
             oparg = PyLong_AsLong(PyTuple_GET_ITEM(item, 1));
             if (PyErr_Occurred()) {
                 goto error;

@@ -45,14 +45,13 @@ is_block_push(cfg_instr *i)
 static inline int
 is_jump(cfg_instr *i)
 {
-    assert(!OPCODE_HAS_JUMP(i->i_opcode) == !IS_JUMP_OPCODE(i->i_opcode));
     return OPCODE_HAS_JUMP(i->i_opcode);
 }
 
 /* One arg*/
 #define INSTR_SET_OP1(I, OP, ARG) \
     do { \
-        assert(HAS_ARG(OP)); \
+        assert(OPCODE_HAS_ARG(OP)); \
         _PyCfgInstruction *_instr__ptr_ = (I); \
         _instr__ptr_->i_opcode = (OP); \
         _instr__ptr_->i_oparg = (ARG); \
@@ -61,7 +60,7 @@ is_jump(cfg_instr *i)
 /* No args*/
 #define INSTR_SET_OP0(I, OP) \
     do { \
-        assert(!HAS_ARG(OP)); \
+        assert(!OPCODE_HAS_ARG(OP)); \
         _PyCfgInstruction *_instr__ptr_ = (I); \
         _instr__ptr_->i_opcode = (OP); \
         _instr__ptr_->i_oparg = 0; \
@@ -111,7 +110,7 @@ basicblock_addop(basicblock *b, int opcode, int oparg, location loc)
 {
     assert(IS_WITHIN_OPCODE_RANGE(opcode));
     assert(!IS_ASSEMBLER_OPCODE(opcode));
-    assert(HAS_ARG(opcode) || HAS_TARGET(opcode) || oparg == 0);
+    assert(OPCODE_HAS_ARG(opcode) || HAS_TARGET(opcode) || oparg == 0);
     assert(0 <= oparg && oparg < (1 << 30));
 
     int off = basicblock_next_instr(b);
@@ -193,7 +192,7 @@ dump_instr(cfg_instr *i)
     char arg[128];
 
     *arg = '\0';
-    if (HAS_ARG(i->i_opcode)) {
+    if (OPCODE_HAS_ARG(i->i_opcode)) {
         sprintf(arg, "arg: %d ", i->i_oparg);
     }
     if (HAS_TARGET(i->i_opcode)) {
@@ -1108,7 +1107,7 @@ static PyObject*
 get_const_value(int opcode, int oparg, PyObject *co_consts)
 {
     PyObject *constant = NULL;
-    assert(HAS_CONST(opcode));
+    assert(OPCODE_HAS_CONST(opcode));
     if (opcode == LOAD_CONST) {
         constant = PyList_GET_ITEM(co_consts, oparg);
     }
@@ -1139,7 +1138,7 @@ fold_tuple_on_constants(PyObject *const_cache,
     assert(inst[n].i_oparg == n);
 
     for (int i = 0; i < n; i++) {
-        if (!HAS_CONST(inst[i].i_opcode)) {
+        if (!OPCODE_HAS_CONST(inst[i].i_opcode)) {
             return SUCCESS;
         }
     }
@@ -1542,8 +1541,8 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
                 }
                 break;
             default:
-                /* All HAS_CONST opcodes should be handled with LOAD_CONST */
-                assert (!HAS_CONST(inst->i_opcode));
+                /* All OPCODE_HAS_CONST opcodes should be handled with LOAD_CONST */
+                assert (!OPCODE_HAS_CONST(inst->i_opcode));
         }
     }
 
@@ -1793,7 +1792,7 @@ remove_unused_consts(basicblock *entryblock, PyObject *consts)
     /* mark used consts */
     for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
         for (int i = 0; i < b->b_iused; i++) {
-            if (HAS_CONST(b->b_instr[i].i_opcode)) {
+            if (OPCODE_HAS_CONST(b->b_instr[i].i_opcode)) {
                 int index = b->b_instr[i].i_oparg;
                 index_map[index] = index;
             }
@@ -1846,7 +1845,7 @@ remove_unused_consts(basicblock *entryblock, PyObject *consts)
 
     for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
         for (int i = 0; i < b->b_iused; i++) {
-            if (HAS_CONST(b->b_instr[i].i_opcode)) {
+            if (OPCODE_HAS_CONST(b->b_instr[i].i_opcode)) {
                 int index = b->b_instr[i].i_oparg;
                 assert(reverse_index_map[index] >= 0);
                 assert(reverse_index_map[index] < n_used_consts);