aaron.ballman updated this revision to Diff 397061.
aaron.ballman marked 2 inline comments as done.
aaron.ballman added a comment.
Updated release notes and user's manual based on review feedback.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D112221/new/
https://reviews.llvm.org/D112221
Files:
clang/docs/ReleaseNotes.rst
clang/docs/UsersManual.rst
clang/lib/Headers/stdatomic.h
clang/test/Headers/stdatomic-deprecations.c
Index: clang/test/Headers/stdatomic-deprecations.c
===================================================================
--- /dev/null
+++ clang/test/Headers/stdatomic-deprecations.c
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c11 %s -verify=okay
+// RUN: %clang_cc1 -fsyntax-only -std=c17 %s -verify
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -x c++ %s -verify=okay
+// RUN: %clang_cc1 -fsyntax-only -std=c++20 -x c++ %s -verify=cxx,expected
+// RUN: %clang_cc1 -fsyntax-only -std=c++20 -x c++ %s -verify=okay -D_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS
+// RUN: %clang_cc1 -fsyntax-only -std=c17 %s -verify=okay -D_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS
+//
+// okay-no-diagnostics
+
+#include <stdatomic.h>
+
+void func(void) {
+ _Atomic int i = ATOMIC_VAR_INIT(12); // expected-warning {{macro 'ATOMIC_VAR_INIT' has been marked as deprecated}} \
+ // [email protected]:* {{macro marked 'deprecated' here}}
+ #if defined(ATOMIC_FLAG_INIT) // cxx-warning {{macro 'ATOMIC_FLAG_INIT' has been marked as deprecated}} \
+ // [email protected]:* {{macro marked 'deprecated' here}}
+ #endif
+}
Index: clang/lib/Headers/stdatomic.h
===================================================================
--- clang/lib/Headers/stdatomic.h
+++ clang/lib/Headers/stdatomic.h
@@ -44,6 +44,11 @@
/* 7.17.2 Initialization */
#define ATOMIC_VAR_INIT(value) (value)
+#if (__STDC_VERSION__ >= 201710L || __cplusplus >= 202002L) && \
+ !defined(_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS)
+/* ATOMIC_VAR_INIT was deprecated in C17 and C++20. */
+#pragma clang deprecated(ATOMIC_VAR_INIT)
+#endif
#define atomic_init __c11_atomic_init
/* 7.17.3 Order and consistency */
@@ -153,6 +158,10 @@
typedef struct atomic_flag { atomic_bool _Value; } atomic_flag;
#define ATOMIC_FLAG_INIT { 0 }
+#if __cplusplus >= 202002L && !defined(_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS)
+/* ATOMIC_FLAG_INIT was deprecated in C++20 but is not deprecated in C. */
+#pragma clang deprecated(ATOMIC_FLAG_INIT)
+#endif
/* These should be provided by the libc implementation. */
#ifdef __cplusplus
Index: clang/docs/UsersManual.rst
===================================================================
--- clang/docs/UsersManual.rst
+++ clang/docs/UsersManual.rst
@@ -1132,10 +1132,28 @@
directory is treated as including a system header if the including file
is treated as a system header.
+Controlling Deprecation Diagnostics in Clang-Provided C Runtime Headers
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Clang is responsible for providing some of the C runtime headers that cannot be
+provided by a platform CRT, such as implementation limits or when compiling in
+freestanding mode. Define the ``_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS`` macro
+prior to including such a C runtime header to disable the deprecation warnings.
+Note that the C Standard Library headers are allowed to transitively include
+other standard library headers (see 7.1.2p5), and so the most appropriate use
+of this macro is to set it within the build system using ``-D`` or before any
+include directives in the translation unit.
+
+.. code-block:: c
+
+ #define _CLANG_DISABLE_CRT_DEPRECATION_WARNINGS
+ #include <stdint.h> // Clang CRT deprecation warnings are disabled.
+ #include <stdatomic.h> // Clang CRT deprecation warnings are disabled.
+
.. _diagnostics_enable_everything:
Enabling All Diagnostics
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+^^^^^^^^^^^^^^^^^^^^^^^^
In addition to the traditional ``-W`` flags, one can enable **all** diagnostics
by passing :option:`-Weverything`. This works as expected with
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -159,6 +159,11 @@
stabilized, so this type should not yet be used in interfaces that require
ABI stability.
+- The ``ATOMIC_VAR_INIT`` macro from ``<stdatomic.h>`` is now diagnosed as
+ deprecated in C17 and later. The diagnostic can be disabled by defining the
+ ``_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS`` macro prior to including the
+ header.
+
C++ Language Changes in Clang
-----------------------------
@@ -166,7 +171,15 @@
C++20 Feature Support
^^^^^^^^^^^^^^^^^^^^^
-...
+
+- The ``ATOMIC_VAR_INIT`` and ``ATOMIC_FLAG_INIT`` macros from the C standard
+ library ``<stdatomic.h>`` header are now diagnosed as deprecated in C++20 and
+ later. Note, the behavior is specific to the inclusion of ``<stdatomic.h>``
+ in C++ code; the STL ``<atomic>`` header also controls the behavior of these
+ macros and is not impacted by these changes. The ``<stdatomic.h>`` diagnostic
+ can be disabled by defining the ``_CLANG_DISABLE_CRT_DEPRECATION_WARNINGS``
+ macro prior to including the header.
+
C++2b Feature Support
^^^^^^^^^^^^^^^^^^^^^
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