[Python-checkins] bpo-45094: Add Py_NO_INLINE macro (GH-28140)
vstinner
webhook-mailer at python.org
Fri Sep 3 10:45:17 EDT 2021
https://github.com/python/cpython/commit/7974c30b9fd84fa56ea1515ed2c08b38edf1a383
commit: 7974c30b9fd84fa56ea1515ed2c08b38edf1a383
branch: main
author: Victor Stinner <vstinner at python.org>
committer: vstinner <vstinner at python.org>
date: 2021-09-03T16:44:02+02:00
summary:
bpo-45094: Add Py_NO_INLINE macro (GH-28140)
* Rename _Py_NO_INLINE macro to Py_NO_INLINE: make it public and
document it.
* Sort macros in the C API documentation.
files:
A Misc/NEWS.d/next/C API/2021-09-03-15-53-43.bpo-45094.tinXwL.rst
M Doc/c-api/intro.rst
M Include/pymath.h
M Include/pyport.h
M Modules/_functoolsmodule.c
M Modules/_io/bytesio.c
M Modules/_posixsubprocess.c
M Python/marshal.c
diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst
index 2d85d30702df9..83824bb474fbd 100644
--- a/Doc/c-api/intro.rst
+++ b/Doc/c-api/intro.rst
@@ -105,45 +105,63 @@ defined closer to where they are useful (e.g. :c:macro:`Py_RETURN_NONE`).
Others of a more general utility are defined here. This is not necessarily a
complete listing.
-.. c:macro:: Py_UNREACHABLE()
+.. c:macro:: Py_ABS(x)
- Use this when you have a code path that cannot be reached by design.
- For example, in the ``default:`` clause in a ``switch`` statement for which
- all possible values are covered in ``case`` statements. Use this in places
- where you might be tempted to put an ``assert(0)`` or ``abort()`` call.
+ Return the absolute value of ``x``.
- In release mode, the macro helps the compiler to optimize the code, and
- avoids a warning about unreachable code. For example, the macro is
- implemented with ``__builtin_unreachable()`` on GCC in release mode.
+ .. versionadded:: 3.3
- A use for ``Py_UNREACHABLE()`` is following a call a function that
- never returns but that is not declared :c:macro:`_Py_NO_RETURN`.
+.. c:macro:: Py_CHARMASK(c)
- If a code path is very unlikely code but can be reached under exceptional
- case, this macro must not be used. For example, under low memory condition
- or if a system call returns a value out of the expected range. In this
- case, it's better to report the error to the caller. If the error cannot
- be reported to caller, :c:func:`Py_FatalError` can be used.
+ Argument must be a character or an integer in the range [-128, 127] or [0,
+ 255]. This macro returns ``c`` cast to an ``unsigned char``.
- .. versionadded:: 3.7
+.. c:macro:: Py_DEPRECATED(version)
-.. c:macro:: Py_ABS(x)
+ Use this for deprecated declarations. The macro must be placed before the
+ symbol name.
- Return the absolute value of ``x``.
+ Example::
+
+ Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);
+
+ .. versionchanged:: 3.8
+ MSVC support was added.
+
+.. c:macro:: Py_GETENV(s)
+
+ Like ``getenv(s)``, but returns ``NULL`` if :option:`-E` was passed on the
+ command line (i.e. if ``Py_IgnoreEnvironmentFlag`` is set).
+
+.. c:macro:: Py_MAX(x, y)
+
+ Return the maximum value between ``x`` and ``y``.
.. versionadded:: 3.3
+.. c:macro:: Py_MEMBER_SIZE(type, member)
+
+ Return the size of a structure (``type``) ``member`` in bytes.
+
+ .. versionadded:: 3.6
+
.. c:macro:: Py_MIN(x, y)
Return the minimum value between ``x`` and ``y``.
.. versionadded:: 3.3
-.. c:macro:: Py_MAX(x, y)
+.. c:macro:: Py_NO_INLINE
- Return the maximum value between ``x`` and ``y``.
+ Disable inlining on a function. For example, it reduces the C stack
+ consumption: useful on LTO+PGO builds which heavily inline code (see
+ :issue:`33720`).
- .. versionadded:: 3.3
+ Usage::
+
+ Py_NO_INLINE static int random(void) { return 4; }
+
+ .. versionadded:: 3.11
.. c:macro:: Py_STRINGIFY(x)
@@ -152,21 +170,27 @@ complete listing.
.. versionadded:: 3.4
-.. c:macro:: Py_MEMBER_SIZE(type, member)
-
- Return the size of a structure (``type``) ``member`` in bytes.
+.. c:macro:: Py_UNREACHABLE()
- .. versionadded:: 3.6
+ Use this when you have a code path that cannot be reached by design.
+ For example, in the ``default:`` clause in a ``switch`` statement for which
+ all possible values are covered in ``case`` statements. Use this in places
+ where you might be tempted to put an ``assert(0)`` or ``abort()`` call.
-.. c:macro:: Py_CHARMASK(c)
+ In release mode, the macro helps the compiler to optimize the code, and
+ avoids a warning about unreachable code. For example, the macro is
+ implemented with ``__builtin_unreachable()`` on GCC in release mode.
- Argument must be a character or an integer in the range [-128, 127] or [0,
- 255]. This macro returns ``c`` cast to an ``unsigned char``.
+ A use for ``Py_UNREACHABLE()`` is following a call a function that
+ never returns but that is not declared :c:macro:`_Py_NO_RETURN`.
-.. c:macro:: Py_GETENV(s)
+ If a code path is very unlikely code but can be reached under exceptional
+ case, this macro must not be used. For example, under low memory condition
+ or if a system call returns a value out of the expected range. In this
+ case, it's better to report the error to the caller. If the error cannot
+ be reported to caller, :c:func:`Py_FatalError` can be used.
- Like ``getenv(s)``, but returns ``NULL`` if :option:`-E` was passed on the
- command line (i.e. if ``Py_IgnoreEnvironmentFlag`` is set).
+ .. versionadded:: 3.7
.. c:macro:: Py_UNUSED(arg)
@@ -175,18 +199,6 @@ complete listing.
.. versionadded:: 3.4
-.. c:macro:: Py_DEPRECATED(version)
-
- Use this for deprecated declarations. The macro must be placed before the
- symbol name.
-
- Example::
-
- Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);
-
- .. versionchanged:: 3.8
- MSVC support was added.
-
.. c:macro:: PyDoc_STRVAR(name, str)
Creates a variable with name ``name`` that can be used in docstrings.
@@ -221,6 +233,7 @@ complete listing.
{NULL, NULL}
};
+
.. _api-objects:
Objects, Types and Reference Counts
diff --git a/Include/pymath.h b/Include/pymath.h
index f869724334a4c..ebb3b05f1b53c 100644
--- a/Include/pymath.h
+++ b/Include/pymath.h
@@ -163,12 +163,7 @@ PyAPI_FUNC(void) _Py_set_387controlword(unsigned short);
#pragma float_control(push)
#pragma float_control(precise, on)
#pragma float_control(except, on)
- #if defined(_MSC_VER)
- __declspec(noinline)
- #else /* Linux */
- __attribute__((noinline))
- #endif /* _MSC_VER */
- static double __icc_nan()
+ Py_NO_INLINE static double __icc_nan()
{
return sqrt(-1.0);
}
diff --git a/Include/pyport.h b/Include/pyport.h
index b2b53dd2f771b..0aaa4eedd31a1 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -557,19 +557,20 @@ extern "C" {
#define _Py_HOT_FUNCTION
#endif
-/* _Py_NO_INLINE
- * Disable inlining on a function. For example, it helps to reduce the C stack
- * consumption.
- *
- * Usage:
- * int _Py_NO_INLINE x(void) { return 3; }
- */
-#if defined(_MSC_VER)
-# define _Py_NO_INLINE __declspec(noinline)
-#elif defined(__GNUC__) || defined(__clang__)
-# define _Py_NO_INLINE __attribute__ ((noinline))
+// Py_NO_INLINE
+// Disable inlining on a function. For example, it reduces the C stack
+// consumption: useful on LTO+PGO builds which heavily inline code (see
+// bpo-33720).
+//
+// Usage:
+//
+// Py_NO_INLINE static int random(void) { return 4; }
+#if defined(__GNUC__) || defined(__clang__) || defined(__INTEL_COMPILER)
+# define Py_NO_INLINE __attribute__ ((noinline))
+#elif defined(_MSC_VER)
+# define Py_NO_INLINE __declspec(noinline)
#else
-# define _Py_NO_INLINE
+# define Py_NO_INLINE
#endif
/**************************************************************************
diff --git a/Misc/NEWS.d/next/C API/2021-09-03-15-53-43.bpo-45094.tinXwL.rst b/Misc/NEWS.d/next/C API/2021-09-03-15-53-43.bpo-45094.tinXwL.rst
new file mode 100644
index 0000000000000..84b01b23b435f
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2021-09-03-15-53-43.bpo-45094.tinXwL.rst
@@ -0,0 +1,2 @@
+Add the :c:macro:`Py_NO_INLINE` macro to disable inlining on a function.
+Patch by Victor Stinner.
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index fa1452168094b..a93c0be6a149a 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -186,7 +186,7 @@ partial_dealloc(partialobject *pto)
/* Merging keyword arguments using the vectorcall convention is messy, so
* if we would need to do that, we stop using vectorcall and fall back
* to using partial_call() instead. */
-_Py_NO_INLINE static PyObject *
+Py_NO_INLINE static PyObject *
partial_vectorcall_fallback(PyThreadState *tstate, partialobject *pto,
PyObject *const *args, size_t nargsf,
PyObject *kwnames)
diff --git a/Modules/_io/bytesio.c b/Modules/_io/bytesio.c
index 2468f45f941e2..930ef7e29dbcf 100644
--- a/Modules/_io/bytesio.c
+++ b/Modules/_io/bytesio.c
@@ -176,7 +176,7 @@ resize_buffer(bytesio *self, size_t size)
object. Returns the number of bytes written, or -1 on error.
Inlining is disabled because it's significantly decreases performance
of writelines() in PGO build. */
-_Py_NO_INLINE static Py_ssize_t
+Py_NO_INLINE static Py_ssize_t
write_bytes(bytesio *self, PyObject *b)
{
if (check_closed(self)) {
diff --git a/Modules/_posixsubprocess.c b/Modules/_posixsubprocess.c
index a58159a277bea..63207de8b9137 100644
--- a/Modules/_posixsubprocess.c
+++ b/Modules/_posixsubprocess.c
@@ -451,7 +451,7 @@ reset_signal_handlers(const sigset_t *child_sigmask)
* If vfork-unsafe functionality is desired after vfork(), consider using
* syscall() to obtain it.
*/
-_Py_NO_INLINE static void
+Py_NO_INLINE static void
child_exec(char *const exec_array[],
char *const argv[],
char *const envp[],
@@ -650,7 +650,7 @@ child_exec(char *const exec_array[],
* child_exec() should not be inlined to avoid spurious -Wclobber warnings from
* GCC (see bpo-35823).
*/
-_Py_NO_INLINE static pid_t
+Py_NO_INLINE static pid_t
do_fork_exec(char *const exec_array[],
char *const argv[],
char *const envp[],
diff --git a/Python/marshal.c b/Python/marshal.c
index 60b818f0dda4a..346384edea618 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -891,7 +891,7 @@ r_float_bin(RFILE *p)
/* Issue #33720: Disable inlining for reducing the C stack consumption
on PGO builds. */
-_Py_NO_INLINE static double
+Py_NO_INLINE static double
r_float_str(RFILE *p)
{
int n;
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