gh-119180: Add LOAD_COMMON_CONSTANT opcode (#119321)

The PEP 649 implementation will require a way to load NotImplementedError
from the bytecode. @markshannon suggested implementing this by converting
LOAD_ASSERTION_ERROR into a more general mechanism for loading constants.

This PR adds this new opcode. I will work on the rest of the implementation
of the PEP separately.

Co-authored-by: Irit Katriel <[email protected]>

Author: JelleZijlstra

Doc/library/dis.rst

@@ -929,12 +929,13 @@ iterations of the loop.
       Exception representation on the stack now consist of one, not three, items.
 
 
-.. opcode:: LOAD_ASSERTION_ERROR
+.. opcode:: LOAD_COMMON_CONSTANT
 
-   Pushes :exc:`AssertionError` onto the stack.  Used by the :keyword:`assert`
-   statement.
+   Pushes a common constant onto the stack. The interpreter contains a hardcoded
+   list of constants supported by this instruction.  Used by the :keyword:`assert`
+   statement to load :exc:`AssertionError`.
 
-   .. versionadded:: 3.9
+   .. versionadded:: 3.14
 
 
 .. opcode:: LOAD_BUILD_CLASS

Include/internal/pycore_opcode_metadata.h

@@ -58,6 +58,11 @@ extern "C" {
 #define MAKE_FUNCTION_ANNOTATIONS 0x04
 #define MAKE_FUNCTION_CLOSURE     0x08
 
+/* Values used as the oparg for LOAD_COMMON_CONSTANT */
+#define CONSTANT_ASSERTIONERROR 0
+#define CONSTANT_NOTIMPLEMENTEDERROR 1
+#define NUM_COMMON_CONSTANTS 2
+
 /* Values used in the oparg for RESUME */
 #define RESUME_AT_FUNC_START 0
 #define RESUME_AFTER_YIELD 1