mypyc/common.py

from __future__ import annotations

import importlib.machinery
import sys
import sysconfig
from typing import Any, Final

from mypy.util import unnamed_function
from mypyc.namegen import exported_name

PREFIX: Final = "CPyPy_"  # Python wrappers
NATIVE_PREFIX: Final = "CPyDef_"  # Native functions etc.
DUNDER_PREFIX: Final = "CPyDunder_"  # Wrappers for exposing dunder methods to the API
REG_PREFIX: Final = "cpy_r_"  # Registers
STATIC_PREFIX: Final = "CPyStatic_"  # Static variables (for literals etc.)
TYPE_PREFIX: Final = "CPyType_"  # Type object struct
MODULE_PREFIX: Final = "CPyModule_"  # Cached modules
IMPORT_STATE_PREFIX: Final = "CPyImportState_"  # Native module initialization state
MODULE_LOCK_API_PREFIX: Final = "CPyModuleLockAPI_"  # CPython module-lock API cache
TYPE_VAR_PREFIX: Final = "CPyTypeVar_"  # Type variables when using new-style Python 3.12 syntax
ATTR_PREFIX: Final = "_"  # Attributes
FAST_PREFIX: Final = "__mypyc_fast_"  # Optimized methods in non-extension classes

ENV_ATTR_NAME: Final = "__mypyc_env__"
NEXT_LABEL_ATTR_NAME: Final = "__mypyc_next_label__"
GENERATOR_HELPER_NAME: Final = "__mypyc_generator_helper__"
TEMP_ATTR_NAME: Final = "__mypyc_temp__"
LAMBDA_NAME: Final = "__mypyc_lambda__"
PROPSET_PREFIX: Final = "__mypyc_setter__"
SELF_NAME: Final = "__mypyc_self__"
MYPYC_DEFAULTS_SETUP: Final = "__mypyc_defaults_setup"
GENERATOR_ATTRIBUTE_PREFIX: Final = "__mypyc_generator_attribute__"
GENERATOR_FRAME_ATTRIBUTE_PREFIX: Final = "__mypyc_generator_frame_attribute__"
CPYFUNCTION_NAME = "__cpyfunction__"


def module_import_state_name(module_name: str) -> str:
    return f"{IMPORT_STATE_PREFIX}{exported_name(module_name)}"


def module_lock_api_name(group_name: str) -> str:
    return f"{MODULE_LOCK_API_PREFIX}{exported_name(group_name)}"


def module_init_only_name(module_name: str) -> str:
    return f"CPyInitOnly_{exported_name(module_name)}"


def module_init_name(module_name: str) -> str:
    return f"CPyInit_{exported_name(module_name)}"


def module_exec_name(module_name: str) -> str:
    return f"CPyExec_{exported_name(module_name)}"


def generator_frame_attribute_prefix(class_fullname: str, *, is_final_class: bool) -> str:
    """Return the source-attribute prefix private to a generator frame class."""
    if is_final_class:
        return GENERATOR_FRAME_ATTRIBUTE_PREFIX
    return f"{GENERATOR_FRAME_ATTRIBUTE_PREFIX}{exported_name(class_fullname)}_"


def source_name_from_generator_attribute(name: str, class_fullname: str) -> str:
    """Recover a source name from a generator frame or closure attribute."""
    qualified_prefix = generator_frame_attribute_prefix(class_fullname, is_final_class=False)
    if name.startswith(qualified_prefix):
        return name.removeprefix(qualified_prefix)
    if name.startswith(GENERATOR_FRAME_ATTRIBUTE_PREFIX):
        return name.removeprefix(GENERATOR_FRAME_ATTRIBUTE_PREFIX)
    return name.removeprefix(GENERATOR_ATTRIBUTE_PREFIX)


# Omits the prefix added to user attribute fields, so it cannot collide with one.
RUNNING_FIELD: Final = "mypyc_running"

# Max short int we accept as a literal is based on 32-bit platforms,
# so that we can just always emit the same code.

TOP_LEVEL_NAME: Final = "__top_level__"  # Special function representing module top level

# Maximal number of subclasses for a class to trigger fast path in isinstance() checks.
FAST_ISINSTANCE_MAX_SUBCLASSES: Final = 2

# Size of size_t, if configured.
SIZEOF_SIZE_T_SYSCONFIG: Final = sysconfig.get_config_var("SIZEOF_SIZE_T")

SIZEOF_SIZE_T: Final = (
    int(SIZEOF_SIZE_T_SYSCONFIG)
    if SIZEOF_SIZE_T_SYSCONFIG is not None
    else (sys.maxsize + 1).bit_length() // 8
)

IS_32_BIT_PLATFORM: Final = int(SIZEOF_SIZE_T) == 4

PLATFORM_SIZE = 4 if IS_32_BIT_PLATFORM else 8

# Maximum value for a short tagged integer.
MAX_SHORT_INT: Final = 2 ** (8 * int(SIZEOF_SIZE_T) - 2) - 1

# Minimum value for a short tagged integer.
MIN_SHORT_INT: Final = -(MAX_SHORT_INT) - 1

# Maximum value for a short tagged integer represented as a C integer literal.
#
# Note: Assume that the compiled code uses the same bit width as mypyc
MAX_LITERAL_SHORT_INT: Final = MAX_SHORT_INT
MIN_LITERAL_SHORT_INT: Final = -MAX_LITERAL_SHORT_INT - 1

# Description of the C type used to track the definedness of attributes and
# the presence of argument default values that have types with overlapping
# error values. Each tracked attribute/argument has a dedicated bit in the
# relevant bitmap.
BITMAP_TYPE: Final = "uint32_t"
BITMAP_BITS: Final = 32

# Constant for keeping a (often borrowed) op alive for a short time (a few subexpressions,
# no arbitrary computation or memory allocations), until flush_keep_alives() is called.
KEEP_ALIVE_SHORT_LIVED: Final = 0
# Keep value alive longer, up to until the current top-level expression has been fully
# evaluated. This allows keeping alive values across function calls and arbitrary
# computation. Note that some expressions (e.g. lambdas), restrict the scope of borrowing.
KEEP_ALIVE_WHOLE_EXPRESSION: Final = 1

# Runtime C library files that are always included (some ops may bring
# extra dependencies via mypyc.ir.deps.SourceDep or mypyc.ir.deps.HeaderDep)
RUNTIME_C_FILES: Final = [
    "init.c",
    "getargs.c",
    "getargsfast.c",
    "int_ops.c",
    "float_ops.c",
    "str_ops.c",
    "bytes_ops.c",
    "list_ops.c",
    "dict_ops.c",
    "set_ops.c",
    "tuple_ops.c",
    "exc_ops.c",
    "misc_ops.c",
    "locks.c",
    "generic_ops.c",
    "pythonsupport.c",
    "function_wrapper.c",
]

# Python 3.12 introduced immortal objects, specified via a special reference count
# value. The reference counts of immortal objects are normally not modified, but it's
# not strictly wrong to modify them. See PEP 683 for more information, but note that
# some details in the PEP are out of date.
HAVE_IMMORTAL: Final = sys.version_info >= (3, 12)

# Are we running on a free-threaded build (GIL disabled)? This implies that
# we are on Python 3.13 or later.
IS_FREE_THREADED: Final = bool(sysconfig.get_config_var("Py_GIL_DISABLED"))

# The file extension suffix for C extension modules on the current platform
# (e.g. ".cpython-312-x86_64-linux-gnu.so" or ".pyd").
_EXT_SUFFIXES: Final = importlib.machinery.EXTENSION_SUFFIXES
EXT_SUFFIX: Final = _EXT_SUFFIXES[0] if _EXT_SUFFIXES else ".so"


JsonDict = dict[str, Any]


def shared_lib_name(group_name: str) -> str:
    """Given a group name, return the actual name of its extension module.

    (This just adds a suffix to the final component.)
    """
    return f"{group_name}__mypyc"


def short_name(name: str) -> str:
    if name.startswith("builtins."):
        return name[9:]
    return name


def get_id_from_name(name: str, fullname: str, line: int) -> str:
    """Create a unique id for a function.

    This creates an id that is unique for any given function definition, so that it can be used as
    a dictionary key. This is usually the fullname of the function, but this is different in that
    it handles the case where the function is named '_', in which case multiple different functions
    could have the same name."""
    if unnamed_function(name):
        return f"{fullname}.{line}"
    else:
        return fullname


def short_id_from_name(func_name: str, shortname: str, line: int | None) -> str:
    if unnamed_function(func_name):
        assert line is not None
        partial_name = f"{shortname}.{line}"
    else:
        partial_name = shortname
    return partial_name


def bitmap_name(index: int) -> str:
    if index == 0:
        return "__bitmap"
    return f"__bitmap{index + 1}"