The code for Tier 2 is now only compiled when configured
with `--enable-experimental-jit[=yes|interpreter]`.
We drop support for `PYTHON_UOPS` and -`Xuops`,
but you can disable the interpreter or JIT
at runtime by setting `PYTHON_JIT=0`.
You can also build it without enabling it by default
using `--enable-experimental-jit=yes-off`;
enable with `PYTHON_JIT=1`.
On Windows, the `build.bat` script supports
`--experimental-jit`, `--experimental-jit-off`,
`--experimental-interpreter`.
In the C code, `_Py_JIT` is defined as before
when the JIT is enabled; the new variable
`_Py_TIER2` is defined when the JIT *or* the
interpreter is enabled. It is actually a bitmask:
1: JIT; 2: default-off; 4: interpreter.
* Rename _PyUnstable_GetUnaryIntrinsicName() to
PyUnstable_GetUnaryIntrinsicName()
* Rename _PyUnstable_GetBinaryIntrinsicName()
to PyUnstable_GetBinaryIntrinsicName().
* pycore_intrinsics.h does nothing if included twice
(add #ifndef and #define).
* Update Tools/cases_generator/generate_cases.py to generate the
Py_BUILD_CORE test.
* _bz2, _lzma, _opcode and zlib extensions now define the
Py_BUILD_CORE_MODULE macro to use internal headers
(pycore_code.h, pycore_intrinsics.h and pycore_blocks_output_buffer.h).
Here we are doing no more than adding the value for Py_mod_multiple_interpreters and using it for stdlib modules. We will start checking for it in gh-104206 (once PyInterpreterState.ceval.own_gil is added in gh-104204).
"Zero cost" exception handling.
* Uses a lookup table to determine how to handle exceptions.
* Removes SETUP_FINALLY and POP_TOP block instructions, eliminating (most of) the runtime overhead of try statements.
* Reduces the size of the frame object by about 60%.
The new syntax is highly human readable while still preventing false
positives. The syntax also extends Python syntax to denote "self" and
positional-only parameters, allowing inspect.Signature objects to be
totally accurate for all supported builtins in Python 3.4.
annotate text signatures in docstrings, resulting in fewer false
positives. "self" parameters are also explicitly marked, allowing
inspect.Signature() to authoritatively detect (and skip) said parameters.
Issue #20326: Argument Clinic now generates separate checksums for the
input and output sections of the block, allowing external tools to verify
that the input has not changed (and thus the output is not out-of-date).
PyMethodDescr_Type, _PyMethodWrapper_Type, and PyWrapperDescr_Type)
have been modified to provide introspection information for builtins.
Also: many additional Lib, test suite, and Argument Clinic fixes.
* You may now specify an expression as the default value for a
parameter! Example: "sys.maxsize - 1". This support is
intentionally quite limited; you may only use values that
can be represented as static C values.
* Removed "doc_default", simplified support for "c_default"
and "py_default". (I'm not sure we still even need
"py_default", but I'm leaving it in for now in case a
use presents itself.)
* Parameter lines support a trailing '\\' as a line
continuation character, allowing you to break up long lines.
* The argument parsing code generated when supporting optional
groups now uses PyTuple_GET_SIZE instead of PyTuple_GetSize,
leading to a 850% speedup in parsing. (Just kidding, this
is an unmeasurable difference.)
* A bugfix for the recent regression where the generated
prototype from pydoc for builtins would be littered with
unreadable "=<object ...>"" default values for parameters
that had no default value.
* Converted some asserts into proper failure messages.
* Many doc improvements and fixes.
Guido van Rossum
Irit Katriel
Serhiy Storchaka
Victor Stinner
Eric Snow
Mark Shannon
Mohamed Koubaa
Larry Hastings
Benjamin Peterson