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authorcyfraeviolae <cyfraeviolae>2024-04-03 03:10:44 -0400
committercyfraeviolae <cyfraeviolae>2024-04-03 03:10:44 -0400
commit6d7ba58f880be618ade07f8ea080fe8c4bf8a896 (patch)
treeb1c931051ffcebd2bd9d61d98d6233ffa289bbce /venv/lib/python3.11/site-packages/greenlet/greenlet_compiler_compat.hpp
parent4f884c9abc32990b4061a1bb6997b4b37e58ea0b (diff)
venv
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+/* -*- indent-tabs-mode: nil; tab-width: 4; -*- */
+#ifndef GREENLET_COMPILER_COMPAT_HPP
+#define GREENLET_COMPILER_COMPAT_HPP
+
+/**
+ * Definitions to aid with compatibility with different compilers.
+ *
+ * .. caution:: Use extreme care with noexcept.
+ * Some compilers and runtimes, specifically gcc/libgcc/libstdc++ on
+ * Linux, implement stack unwinding by throwing an uncatchable
+ * exception, one that specifically does not appear to be an active
+ * exception to the rest of the runtime. If this happens while we're in a noexcept function,
+ * we have violated our dynamic exception contract, and so the runtime
+ * will call std::terminate(), which kills the process with the
+ * unhelpful message "terminate called without an active exception".
+ *
+ * This has happened in this scenario: A background thread is running
+ * a greenlet that has made a native call and released the GIL.
+ * Meanwhile, the main thread finishes and starts shutting down the
+ * interpreter. When the background thread is scheduled again and
+ * attempts to obtain the GIL, it notices that the interpreter is
+ * exiting and calls ``pthread_exit()``. This in turn starts to unwind
+ * the stack by throwing that exception. But we had the ``PyCall``
+ * functions annotated as noexcept, so the runtime terminated us.
+ *
+ * #2 0x00007fab26fec2b7 in std::terminate() () from /lib/x86_64-linux-gnu/libstdc++.so.6
+ * #3 0x00007fab26febb3c in __gxx_personality_v0 () from /lib/x86_64-linux-gnu/libstdc++.so.6
+ * #4 0x00007fab26f34de6 in ?? () from /lib/x86_64-linux-gnu/libgcc_s.so.1
+ * #6 0x00007fab276a34c6 in __GI___pthread_unwind at ./nptl/unwind.c:130
+ * #7 0x00007fab2769bd3a in __do_cancel () at ../sysdeps/nptl/pthreadP.h:280
+ * #8 __GI___pthread_exit (value=value@entry=0x0) at ./nptl/pthread_exit.c:36
+ * #9 0x000000000052e567 in PyThread_exit_thread () at ../Python/thread_pthread.h:370
+ * #10 0x00000000004d60b5 in take_gil at ../Python/ceval_gil.h:224
+ * #11 0x00000000004d65f9 in PyEval_RestoreThread at ../Python/ceval.c:467
+ * #12 0x000000000060cce3 in setipaddr at ../Modules/socketmodule.c:1203
+ * #13 0x00000000006101cd in socket_gethostbyname
+ */
+
+#include <cstdint>
+
+# if defined(__clang__)
+# define G_FP_TMPL_STATIC static
+# else
+// GCC has no problem allowing static function pointers, but emits
+// tons of warnings about "whose type uses the anonymous namespace [-Wsubobject-linkage]"
+# define G_FP_TMPL_STATIC
+# endif
+
+# define G_NO_COPIES_OF_CLS(Cls) private: \
+ Cls(const Cls& other) = delete; \
+ Cls& operator=(const Cls& other) = delete
+
+# define G_NO_ASSIGNMENT_OF_CLS(Cls) private: \
+ Cls& operator=(const Cls& other) = delete
+
+# define G_NO_COPY_CONSTRUCTOR_OF_CLS(Cls) private: \
+ Cls(const Cls& other) = delete;
+
+
+// CAUTION: MSVC is stupidly picky:
+//
+// "The compiler ignores, without warning, any __declspec keywords
+// placed after * or & and in front of the variable identifier in a
+// declaration."
+// (https://docs.microsoft.com/en-us/cpp/cpp/declspec?view=msvc-160)
+//
+// So pointer return types must be handled differently (because of the
+// trailing *), or you get inscrutable compiler warnings like "error
+// C2059: syntax error: ''"
+//
+// In C++ 11, there is a standard syntax for attributes, and
+// GCC defines an attribute to use with this: [[gnu:noinline]].
+// In the future, this is expected to become standard.
+
+#if defined(__GNUC__) || defined(__clang__)
+/* We used to check for GCC 4+ or 3.4+, but those compilers are
+ laughably out of date. Just assume they support it. */
+# define GREENLET_NOINLINE(name) __attribute__((noinline)) name
+# define GREENLET_NOINLINE_P(rtype, name) rtype __attribute__((noinline)) name
+# define UNUSED(x) UNUSED_ ## x __attribute__((__unused__))
+#elif defined(_MSC_VER)
+/* We used to check for && (_MSC_VER >= 1300) but that's also out of date. */
+# define GREENLET_NOINLINE(name) __declspec(noinline) name
+# define GREENLET_NOINLINE_P(rtype, name) __declspec(noinline) rtype name
+# define UNUSED(x) UNUSED_ ## x
+#endif
+
+#if defined(_MSC_VER)
+# define G_NOEXCEPT_WIN32 noexcept
+#else
+# define G_NOEXCEPT_WIN32
+#endif
+
+
+#endif