[libcamera-devel,v2,04/11] libcamera: base: Add thread safety annotation macros

14840 diff mbox series

Clang complier is able to do a thread safety analysis with
annotations [1]. This introduces the thread safety annotation
macros and also enable the analysis by adding -Wthread-safety
if a clang compiler is used.

[1] https://clang.llvm.org/docs/ThreadSafetyAnalysis.html.

Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
---
 include/libcamera/base/meson.build          |  1 +
 include/libcamera/base/thread_annotations.h | 80 +++++++++++++++++++++
 meson.build                                 |  1 +
 3 files changed, 82 insertions(+)
 create mode 100644 include/libcamera/base/thread_annotations.h

Hi Hiro,

Thank you for the patch.

On Mon, Nov 29, 2021 at 08:44:46PM +0900, Hirokazu Honda wrote:
> Clang complier is able to do a thread safety analysis with

s/complier/compiler/

> annotations [1]. This introduces the thread safety annotation
> macros and also enable the analysis by adding -Wthread-safety
> if a clang compiler is used.
> 
> [1] https://clang.llvm.org/docs/ThreadSafetyAnalysis.html.
> 
> Signed-off-by: Hirokazu Honda <hiroh@chromium.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  include/libcamera/base/meson.build          |  1 +
>  include/libcamera/base/thread_annotations.h | 80 +++++++++++++++++++++
>  meson.build                                 |  1 +
>  3 files changed, 82 insertions(+)
>  create mode 100644 include/libcamera/base/thread_annotations.h
> 
> diff --git a/include/libcamera/base/meson.build b/include/libcamera/base/meson.build
> index 525aba9d..1a71ce5a 100644
> --- a/include/libcamera/base/meson.build
> +++ b/include/libcamera/base/meson.build
> @@ -19,6 +19,7 @@ libcamera_base_headers = files([
>      'signal.h',
>      'span.h',
>      'thread.h',
> +    'thread_annotations.h',
>      'timer.h',
>      'utils.h',
>  ])
> diff --git a/include/libcamera/base/thread_annotations.h b/include/libcamera/base/thread_annotations.h
> new file mode 100644
> index 00000000..e81929f6
> --- /dev/null
> +++ b/include/libcamera/base/thread_annotations.h
> @@ -0,0 +1,80 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Google Inc.
> + *
> + * thread_annotation.h - Macro of Clang thread safety analysis
> + */
> +
> +#pragma once
> +
> +/*
> + * Enable thread safety attributes only with clang.
> + * The attributes can be safely erased when compiling with other compilers.
> + */
> +#if defined(__clang__) && !defined(SWIG)
> +#define LIBCAMERA_TSA_ATTRIBUTE__(x) __attribute__((x))
> +#else
> +#define LIBCAMERA_TSA_ATTRIBUTE__(x) /* no-op */
> +#endif
> +
> +/* See https://clang.llvm.org/docs/ThreadSafetyAnalysis.html for these usages. */
> +
> +#define LIBCAMERA_TSA_CAPABILITY(x)			\
> +	LIBCAMERA_TSA_ATTRIBUTE__(capability(x))
> +
> +#define LIBCAMERA_TSA_SCOPED_CAPABILITY			\
> +	LIBCAMERA_TSA_ATTRIBUTE__(scoped_lockable)
> +
> +#define LIBCAMERA_TSA_GUARDED_BY(x)			\
> +	LIBCAMERA_TSA_ATTRIBUTE__(guarded_by(x))
> +
> +#define LIBCAMERA_TSA_PT_GUARDED_BY(x)			\
> +	LIBCAMERA_TSA_ATTRIBUTE__(pt_guarded_by(x))
> +
> +#define LIBCAMERA_TSA_ACQUIRED_BEFORE(...)			\
> +	LIBCAMERA_TSA_ATTRIBUTE__(acquired_before(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_ACQUIRED_AFTER(...)			\
> +	LIBCAMERA_TSA_ATTRIBUTE__(acquired_after(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_REQUIRES(...)					\
> +	LIBCAMERA_TSA_ATTRIBUTE__(requires_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_REQUIRES_SHARED(...)				\
> +	LIBCAMERA_TSA_ATTRIBUTE__(requires_shared_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_ACQUIRE(...)					\
> +	LIBCAMERA_TSA_ATTRIBUTE__(acquire_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_ACQUIRE_SHARED(...)				\
> +	LIBCAMERA_TSA_ATTRIBUTE__(acquire_shared_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_RELEASE(...)					\
> +	LIBCAMERA_TSA_ATTRIBUTE__(release_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_RELEASE_SHARED(...)				\
> +	LIBCAMERA_TSA_ATTRIBUTE__(release_shared_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_RELEASE_GENERIC(...)				\
> +	LIBCAMERA_TSA_ATTRIBUTE__(release_generic_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_TRY_ACQUIRE(...)					\
> +	LIBCAMERA_TSA_ATTRIBUTE__(try_acquire_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_TRY_ACQUIRE_SHARED(...)				\
> +	LIBCAMERA_TSA_ATTRIBUTE__(try_acquire_shared_capability(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_EXCLUDES(...)				\
> +	LIBCAMERA_TSA_ATTRIBUTE__(locks_excluded(__VA_ARGS__))
> +
> +#define LIBCAMERA_TSA_ASSERT_CAPABILITY(x)		\
> +	LIBCAMERA_TSA_ATTRIBUTE__(assert_capability(x))
> +
> +#define LIBCAMERA_TSA_ASSERT_SHARED_CAPABILITY(x)		\
> +	LIBCAMERA_TSA_ATTRIBUTE__(assert_shared_capability(x))
> +
> +#define LIBCAMERA_TSA_RETURN_CAPABILITY(x)		\
> +	LIBCAMERA_TSA_ATTRIBUTE__(lock_returned(x))
> +
> +#define LIBCAMERA_TSA_NO_THREAD_SAFETY_ANALYSIS			\
> +	LIBCAMERA_TSA_ATTRIBUTE__(no_thread_safety_analysis)
> diff --git a/meson.build b/meson.build
> index 7892a9e3..7147a108 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -72,6 +72,7 @@ if cc.get_id() == 'clang'
>  
>      cpp_arguments += [
>          '-Wextra-semi',
> +        '-Wthread-safety',
>      ]
>  endif
>