[Python-checkins] cpython: Implement the frame evaluation API aspect of PEP 523.
brett.cannon
python-checkins at python.org
Mon Sep 5 18:33:59 EDT 2016
https://hg.python.org/cpython/rev/584855b437d4
changeset: 103080:584855b437d4
user: Brett Cannon <brett at python.org>
date: Mon Sep 05 15:33:46 2016 -0700
summary:
Implement the frame evaluation API aspect of PEP 523.
files:
Doc/whatsnew/3.6.rst | 28 ++++++++++++++++++++++++++++
Include/ceval.h | 3 +++
Include/pystate.h | 7 +++++--
Misc/NEWS | 4 +++-
Python/ceval.c | 7 +++++++
Python/pystate.c | 1 +
6 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/Doc/whatsnew/3.6.rst b/Doc/whatsnew/3.6.rst
--- a/Doc/whatsnew/3.6.rst
+++ b/Doc/whatsnew/3.6.rst
@@ -97,6 +97,34 @@
New Features
============
+.. _pep-523:
+
+PEP 523: Adding a frame evaluation API to CPython
+=================================================
+
+While Python provides extensive support to customize how code
+executes, one place it has not done so is in the evaluation of frame
+objects. If you wanted some way to intercept frame evaluation in
+Python there really wasn't any way without directly manipulating
+function pointers for defined functions.
+
+:pep:`523` changes this by providing an API to make frame
+evaluation pluggable at the C level. This will allow for tools such
+as debuggers and JITs to intercept frame evaluation before the
+execution of Python code begins. This enables the use of alternative
+evaluation implementations for Python code, tracking frame
+evaluation, etc.
+
+This API is not part of the limited C API and is marked as private to
+signal that usage of this API is expected to be limited and only
+applicable to very select, low-level use-cases.
+
+.. seealso::
+
+ :pep:`523` - Adding a frame evaluation API to CPython
+ PEP written by Brett Cannon and Dino Viehland.
+
+
.. _pep-519:
PEP 519: Adding a file system path protocol
diff --git a/Include/ceval.h b/Include/ceval.h
--- a/Include/ceval.h
+++ b/Include/ceval.h
@@ -119,6 +119,9 @@
PyAPI_FUNC(PyObject *) PyEval_GetCallStats(PyObject *);
PyAPI_FUNC(PyObject *) PyEval_EvalFrame(struct _frame *);
PyAPI_FUNC(PyObject *) PyEval_EvalFrameEx(struct _frame *f, int exc);
+#ifndef Py_LIMITED_API
+PyAPI_FUNC(PyObject *) _PyEval_EvalFrameDefault(struct _frame *f, int exc);
+#endif
/* Interface for threads.
diff --git a/Include/pystate.h b/Include/pystate.h
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -12,10 +12,13 @@
struct _ts; /* Forward */
struct _is; /* Forward */
+struct _frame; /* Forward declaration for PyFrameObject. */
#ifdef Py_LIMITED_API
typedef struct _is PyInterpreterState;
#else
+typedef PyObject* (*_PyFrameEvalFunction)(struct _frame *, int);
+
typedef struct _is {
struct _is *next;
@@ -42,14 +45,14 @@
PyObject *builtins_copy;
PyObject *import_func;
+ /* Initialized to PyEval_EvalFrameDefault(). */
+ _PyFrameEvalFunction eval_frame;
} PyInterpreterState;
#endif
/* State unique per thread */
-struct _frame; /* Avoid including frameobject.h */
-
#ifndef Py_LIMITED_API
/* Py_tracefunc return -1 when raising an exception, or 0 for success. */
typedef int (*Py_tracefunc)(PyObject *, struct _frame *, int, PyObject *);
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -17,7 +17,9 @@
restriction: in beta 2, backslashes will only be disallowed inside
the braces (where the expressions are). This is a breaking change
from the 3.6 alpha releases.
-
+
+- Implement the frame evaluation part of PEP 523.
+
- Issue #27870: A left shift of zero by a large integer no longer attempts
to allocate large amounts of memory.
diff --git a/Python/ceval.c b/Python/ceval.c
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -797,6 +797,13 @@
PyObject *
PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
{
+ PyThreadState *tstate = PyThreadState_GET();
+ return tstate->interp->eval_frame(f, throwflag);
+}
+
+PyObject *
+_PyEval_EvalFrameDefault(PyFrameObject *f, int throwflag)
+{
#ifdef DXPAIRS
int lastopcode = 0;
#endif
diff --git a/Python/pystate.c b/Python/pystate.c
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -91,6 +91,7 @@
interp->fscodec_initialized = 0;
interp->importlib = NULL;
interp->import_func = NULL;
+ interp->eval_frame = _PyEval_EvalFrameDefault;
#ifdef HAVE_DLOPEN
#if HAVE_DECL_RTLD_NOW
interp->dlopenflags = RTLD_NOW;
--
Repository URL: https://hg.python.org/cpython
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