Fix Test_Pep523AllowSpecialization tests of test_capi.test_misc.
On Cygwin, _PyEval_EvalFrameDefault in _testinternalcapi is not the
same as _PyEval_EvalFrameDefault in python.exe. So pass NULL
explicitly to use the default function (_PyEval_EvalFrameDefault).
Use exact remote reads for interpreter state, thread state, and
interpreter frame structs instead of pulling full remote pages into the
profiler page cache. This matches the core change from
python/cpython#149585.
The profiler clears the page cache between samples, so live entries are
always packed at the front. Track the live count and only clear/search
that prefix instead of scanning all 1024 slots on the hot path.
Use the frame cache to predict the next thread state and top frame
address, then batch interpreter/thread/frame reads with process_vm_readv
when profiling a Linux target. Reuse prefetched frame buffers in the
frame walker when the prediction is valid.
Cache the last FrameInfo tuple per code object/instruction offset, reuse
cached thread id objects, and append cached parent frames directly on
full frame-cache hits. This cuts Python allocation churn in the
steady-state profiler path.
If queue.SimpleQueue.put can't handoff the item to a
waiting thread, and fails to allocate memory when adding
the item to a ringbuf, it would leak a reference. Fixed.
Remove assertion that could fail in rare race condition.
Replace the coarse critical section wrapping the entire function with
fine-grained sections covering only PyDict_Next + Py_INCREF.
Also handle PyDict_Next returning 0 in the single-item fast path.
`faulthandler_traverse` visits Python objects owned by `_PyRuntime`, not
by the module instance. With multi-phase init allowing multiple module
instances, each instance's GC traversal decrements `gc_refs` on the same
runtime-owned objects, driving it negative when two instances are
collected simultaneously.
Change my_strchr() return type to "const char*" (add "const").
Fix the compiler warning:
Modules/_ctypes/_ctypes_test.c: In function 'my_strchr':
Modules/_ctypes/_ctypes_test.c:451:12: warning: return discards
'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
451 | return strchr(s, c);
| ^~~~~~
When using C23, strchr(text, ch) return type is "const char*" if text
type is "const char*".
In free-threaded builds, concurrent calls to PyDict_AddWatcher, PyDict_ClearWatcher, PyDict_Watch, and PyDict_Unwatch can race on the shared callback array and the per-dict watcher tags. This change adds a mutex to serialize watcher registration and removal, atomic operations for tag updates, and atomic acquire/release synchronization for callback dispatch in _PyDict_SendEvent.
-fno-omit-frame-pointer is not enough to make every target walkable by the
simple manual frame pointer unwinder.
The helper used by test_frame_pointer_unwind used to assume the frame pointer
named a two-word record where fp[0] was the previous frame pointer and fp[1]
was the return address. That is only the generic layout used by some targets.
This patch keeps that default, but moves the slots behind named offsets so
architecture-specific layouts can describe where the backchain and return
address really live.
On s390x, GCC and Clang do not emit a usable backchain unless -mbackchain is
enabled. Without it, the unwinder stops at the current C frame and the test
reports no Python frames. Once backchains are present, the helper must also
stop at the current thread's known C stack bounds; otherwise it can follow the
final backchain far enough to dereference an invalid frame and segfault.
For Linux s390x backchain frames, the documented z/Architecture stack-frame
layout saves r14, the return-address register, at byte offset 112 from the
frame pointer, so read the return address from that named slot instead of fp[1].
The 112-byte offset comes from Linux's s390 debugging documentation: its Stack
Frame Layout table shows z/Architecture backchain frames with the backchain at
offset 0 and saved r14 of the caller function at offset 112:
https://www.kernel.org/doc/html/v5.3/s390/debugging390.html#stack-frame-layout
This helper remains scoped to Linux s390x backchain frames. GNU SFrame's s390x
notes state that the s390x ELF ABI does not generally mandate where RA and FP
are saved, or whether they are saved at all:
https://sourceware.org/binutils/docs/sframe-spec.html#s390x
As Jens Remus noted, -fno-omit-frame-pointer is not needed when -mbackchain is
present.
On 32-bit ARM, GCC defaults to Thumb mode on common armhf toolchains. The Thumb
prologue keeps the saved frame pointer and link register at offsets that depend
on the generated frame, which breaks the fp[0]/fp[1] walk used by the helper.
Use -marm when it is supported for frame-pointer builds, and teach the helper
the GCC ARM-mode slots where the previous frame pointer is at fp[-1] and the
saved LR return address is at fp[0].
Co-authored-by: Petr Viktorin <encukou@gmail.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
* SEND specialization. Adds 2 new specialized instructions:
* SEND_VIRTUAL: for sends to virtual iterators e.g lists and tuples
* SEND_ASYNC_GEN: for sends to async generators
Tweak FOR_ITER_VIRTUAL so that SEND_VIRTUAL and FOR_ITER_VIRTUAL use equivalent guards
