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(216-180-64-156.dyn.novuscom.net. [216.180.64.156]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-724fd95ed01sm5811766b3a.8.2024.11.26.13.18.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Nov 2024 13:18:00 -0800 (PST) From: Pierrick Bouvier To: qemu-devel@nongnu.org Cc: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Stefano Garzarella , "Michael S. Tsirkin" , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , =?utf-8?q?Marc?= =?utf-8?q?-Andr=C3=A9_Lureau?= , Pierrick Bouvier , Thomas Huth , =?utf-8?q?Alex_Benn=C3=A9e?= , Markus Armbruster , Mahmoud Mandour , Paolo Bonzini , Alexandre Iooss Subject: [PATCH v2 1/3] win32: remove usage of attribute gcc_struct Date: Tue, 26 Nov 2024 13:17:34 -0800 Message-Id: <20241126211736.122285-2-pierrick.bouvier@linaro.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241126211736.122285-1-pierrick.bouvier@linaro.org> References: <20241126211736.122285-1-pierrick.bouvier@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::432; envelope-from=pierrick.bouvier@linaro.org; helo=mail-pf1-x432.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org This attribute is not recognized by clang. An investigation has been performed to ensure this attribute has no effect on layout of structures we use in QEMU [1], so it's safe to remove now. In the future, we'll forbid introducing new bitfields in packed struct. [1] https://lore.kernel.org/qemu-devel/66c346de-7e20-4831-b3eb-1cda83240af9@linaro.org/ Signed-off-by: Pierrick Bouvier --- meson.build | 5 ----- include/qemu/compiler.h | 7 +------ scripts/cocci-macro-file.h | 6 +----- subprojects/libvhost-user/libvhost-user.h | 6 +----- 4 files changed, 3 insertions(+), 21 deletions(-) diff --git a/meson.build b/meson.build index e0b880e4e13..fa6d24e1233 100644 --- a/meson.build +++ b/meson.build @@ -354,11 +354,6 @@ elif host_os == 'sunos' qemu_common_flags += '-D__EXTENSIONS__' elif host_os == 'haiku' qemu_common_flags += ['-DB_USE_POSITIVE_POSIX_ERRORS', '-D_BSD_SOURCE', '-fPIC'] -elif host_os == 'windows' - if not compiler.compiles('struct x { int y; } __attribute__((gcc_struct));', - args: '-Werror') - error('Your compiler does not support __attribute__((gcc_struct)) - please use GCC instead of Clang') - endif endif # Choose instruction set (currently x86-only) diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index c06954ccb41..d904408e5ed 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -22,12 +22,7 @@ #define QEMU_EXTERN_C extern #endif -#if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__)) -# define QEMU_PACKED __attribute__((gcc_struct, packed)) -#else -# define QEMU_PACKED __attribute__((packed)) -#endif - +#define QEMU_PACKED __attribute__((packed)) #define QEMU_ALIGNED(X) __attribute__((aligned(X))) #ifndef glue diff --git a/scripts/cocci-macro-file.h b/scripts/cocci-macro-file.h index d247a5086e9..c64831d5408 100644 --- a/scripts/cocci-macro-file.h +++ b/scripts/cocci-macro-file.h @@ -23,11 +23,7 @@ #define G_GNUC_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) #define G_GNUC_NULL_TERMINATED __attribute__((sentinel)) -#if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__)) -# define QEMU_PACKED __attribute__((gcc_struct, packed)) -#else -# define QEMU_PACKED __attribute__((packed)) -#endif +#define QEMU_PACKED __attribute__((packed)) #define cat(x,y) x ## y #define cat2(x,y) cat(x,y) diff --git a/subprojects/libvhost-user/libvhost-user.h b/subprojects/libvhost-user/libvhost-user.h index deb40e77b3f..2ffc58c11b1 100644 --- a/subprojects/libvhost-user/libvhost-user.h +++ b/subprojects/libvhost-user/libvhost-user.h @@ -186,11 +186,7 @@ typedef struct VhostUserShared { unsigned char uuid[UUID_LEN]; } VhostUserShared; -#if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__)) -# define VU_PACKED __attribute__((gcc_struct, packed)) -#else -# define VU_PACKED __attribute__((packed)) -#endif +#define VU_PACKED __attribute__((packed)) typedef struct VhostUserMsg { int request; From patchwork Tue Nov 26 21:17:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierrick Bouvier X-Patchwork-Id: 13886370 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1C63CD6555B for ; Tue, 26 Nov 2024 21:18:59 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tG2wh-0001Vn-0x; 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(216-180-64-156.dyn.novuscom.net. [216.180.64.156]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-724fd95ed01sm5811766b3a.8.2024.11.26.13.18.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Nov 2024 13:18:01 -0800 (PST) From: Pierrick Bouvier To: qemu-devel@nongnu.org Cc: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Stefano Garzarella , "Michael S. Tsirkin" , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , =?utf-8?q?Marc?= =?utf-8?q?-Andr=C3=A9_Lureau?= , Pierrick Bouvier , Thomas Huth , =?utf-8?q?Alex_Benn=C3=A9e?= , Markus Armbruster , Mahmoud Mandour , Paolo Bonzini , Alexandre Iooss Subject: [PATCH v2 2/3] docs/devel/style: add a section about bitfield, and disallow them for packed structures Date: Tue, 26 Nov 2024 13:17:35 -0800 Message-Id: <20241126211736.122285-3-pierrick.bouvier@linaro.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241126211736.122285-1-pierrick.bouvier@linaro.org> References: <20241126211736.122285-1-pierrick.bouvier@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::52d; envelope-from=pierrick.bouvier@linaro.org; helo=mail-pg1-x52d.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Signed-off-by: Pierrick Bouvier --- docs/devel/style.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/docs/devel/style.rst b/docs/devel/style.rst index 2f68b500798..13cb1ef626b 100644 --- a/docs/devel/style.rst +++ b/docs/devel/style.rst @@ -416,6 +416,16 @@ definitions instead of typedefs in headers and function prototypes; this avoids problems with duplicated typedefs and reduces the need to include headers from other headers. +Bitfields +--------- + +C bitfields can be a cause of non-portability issues, especially under windows +where `MSVC has a different way to layout them than gcc +`_. +For this reason, we disallow usage of bitfields in packed structures. +For general usage, using bitfields should be proven to add significant benefits +regarding memory usage or usability. + Reserved namespaces in C and POSIX ---------------------------------- From patchwork Tue Nov 26 21:17:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierrick Bouvier X-Patchwork-Id: 13886372 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 81D0FD65559 for ; 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(216-180-64-156.dyn.novuscom.net. [216.180.64.156]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-724fd95ed01sm5811766b3a.8.2024.11.26.13.18.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Nov 2024 13:18:03 -0800 (PST) From: Pierrick Bouvier To: qemu-devel@nongnu.org Cc: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Stefano Garzarella , "Michael S. Tsirkin" , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , =?utf-8?q?Marc?= =?utf-8?q?-Andr=C3=A9_Lureau?= , Pierrick Bouvier , Thomas Huth , =?utf-8?q?Alex_Benn=C3=A9e?= , Markus Armbruster , Mahmoud Mandour , Paolo Bonzini , Alexandre Iooss Subject: [PATCH v2 3/3] plugins: enable linking with clang/lld Date: Tue, 26 Nov 2024 13:17:36 -0800 Message-Id: <20241126211736.122285-4-pierrick.bouvier@linaro.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241126211736.122285-1-pierrick.bouvier@linaro.org> References: <20241126211736.122285-1-pierrick.bouvier@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::52c; envelope-from=pierrick.bouvier@linaro.org; helo=mail-pg1-x52c.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Windows uses a special mechanism to enable plugins to work (DLL delay loading). Option for lld is different than ld. MSYS2 clang based environment use lld by default, so restricting to this config on Windows is safe, and will avoid false bug reports. Signed-off-by: Pierrick Bouvier --- meson.build | 5 +++++ contrib/plugins/meson.build | 2 +- plugins/meson.build | 24 ++++++++++++++++++++---- tests/tcg/plugins/meson.build | 3 +-- 4 files changed, 27 insertions(+), 7 deletions(-) diff --git a/meson.build b/meson.build index fa6d24e1233..8ccee3f5b34 100644 --- a/meson.build +++ b/meson.build @@ -354,6 +354,11 @@ elif host_os == 'sunos' qemu_common_flags += '-D__EXTENSIONS__' elif host_os == 'haiku' qemu_common_flags += ['-DB_USE_POSITIVE_POSIX_ERRORS', '-D_BSD_SOURCE', '-fPIC'] +elif host_os == 'windows' + # plugins use delaylib, and clang needs to be used with lld to make it work. + if compiler.get_id() == 'clang' and compiler.get_linker_id() != 'ld.lld' + error('On windows, you need to use lld with clang - use msys2 clang64/clangarm64 env') + endif endif # Choose instruction set (currently x86-only) diff --git a/contrib/plugins/meson.build b/contrib/plugins/meson.build index 63a32c2b4f0..484b9a808c8 100644 --- a/contrib/plugins/meson.build +++ b/contrib/plugins/meson.build @@ -12,7 +12,7 @@ if get_option('plugins') t += shared_module(i, files(i + '.c') + 'win32_linker.c', include_directories: '../../include/qemu', link_depends: [win32_qemu_plugin_api_lib], - link_args: ['-Lplugins', '-lqemu_plugin_api'], + link_args: win32_qemu_plugin_api_link_flags, dependencies: glib) else t += shared_module(i, files(i + '.c'), diff --git a/plugins/meson.build b/plugins/meson.build index 98542e926f8..d60be2a4d6d 100644 --- a/plugins/meson.build +++ b/plugins/meson.build @@ -17,14 +17,15 @@ if not enable_modules capture: true, command: ['sed', '-ne', 's/^[[:space:]]*\\(qemu_.*\\);/_\\1/p', '@INPUT@']) emulator_link_args += ['-Wl,-exported_symbols_list,plugins/qemu-plugins-ld64.symbols'] + elif host_os == 'windows' and meson.get_compiler('c').get_id() == 'clang' + # LLVM/lld does not support exporting specific symbols. However, it works + # out of the box with dllexport/dllimport attribute we set in the code. else emulator_link_args += ['-Xlinker', '--dynamic-list=' + qemu_plugin_symbols.full_path()] endif endif if host_os == 'windows' - dlltool = find_program('dlltool', required: true) - # Generate a .lib file for plugins to link against. # First, create a .def file listing all the symbols a plugin should expect to have # available in qemu @@ -33,12 +34,27 @@ if host_os == 'windows' output: 'qemu_plugin_api.def', capture: true, command: ['sed', '-e', '0,/^/s//EXPORTS/; s/[{};]//g', '@INPUT@']) + # then use dlltool to assemble a delaylib. + # The delaylib will have an "imaginary" name (qemu.exe), that is used by the + # linker file we add with plugins (win32_linker.c) to identify that we want + # to find missing symbols in current program. + win32_qemu_plugin_api_link_flags = ['-Lplugins', '-lqemu_plugin_api'] + if meson.get_compiler('c').get_id() == 'clang' + # With LLVM/lld, delaylib is specified at link time (-delayload) + dlltool = find_program('llvm-dlltool', required: true) + dlltool_cmd = [dlltool, '-d', '@INPUT@', '-l', '@OUTPUT@', '-D', 'qemu.exe'] + win32_qemu_plugin_api_link_flags += ['-Wl,-delayload=qemu.exe'] + else + # With gcc/ld, delay lib is built with a specific delay parameter. + dlltool = find_program('dlltool', required: true) + dlltool_cmd = [dlltool, '--input-def', '@INPUT@', + '--output-delaylib', '@OUTPUT@', '--dllname', 'qemu.exe'] + endif win32_qemu_plugin_api_lib = configure_file( input: win32_plugin_def, output: 'libqemu_plugin_api.a', - command: [dlltool, '--input-def', '@INPUT@', - '--output-delaylib', '@OUTPUT@', '--dllname', 'qemu.exe'] + command: dlltool_cmd ) endif specific_ss.add(files( diff --git a/tests/tcg/plugins/meson.build b/tests/tcg/plugins/meson.build index f847849b1b7..87a17d67bd4 100644 --- a/tests/tcg/plugins/meson.build +++ b/tests/tcg/plugins/meson.build @@ -5,9 +5,8 @@ if get_option('plugins') t += shared_module(i, files(i + '.c') + '../../../contrib/plugins/win32_linker.c', include_directories: '../../../include/qemu', link_depends: [win32_qemu_plugin_api_lib], - link_args: ['-Lplugins', '-lqemu_plugin_api'], + link_args: win32_qemu_plugin_api_link_flags, dependencies: glib) - else t += shared_module(i, files(i + '.c'), include_directories: '../../../include/qemu',