From: Rahul Singh <rahul.singh@arm.com>
To: xen-devel@lists.xenproject.org
Cc: bertrand.marquis@arm.com, rahul.singh@arm.com,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Jan Beulich <jbeulich@suse.com>,
Julien Grall <julien@xen.org>,
Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>
Subject: [PATCH v5 07/10] xen/compiler: import 'fallthrough' keyword from linux
Date: Wed, 20 Jan 2021 14:52:41 +0000 [thread overview]
Message-ID: <451cc96ebe70bd7c7ffe34862412adc2f86caaca.1611153615.git.rahul.singh@arm.com> (raw)
In-Reply-To: <cover.1611153615.git.rahul.singh@arm.com>
In-Reply-To: <cover.1611153615.git.rahul.singh@arm.com>
-Wimplicit-fallthrough warns when a switch case falls through. Warning
can be suppress by either adding a /* fallthrough */ comment, or by
using a null statement: __attribute__ ((fallthrough))
Define the pseudo keyword 'fallthrough' for the ability to convert the
various case block /* fallthrough */ style comments to null statement
"__attribute__((__fallthrough__))"
In C mode, GCC supports the __fallthrough__ attribute since 7.1,
the same time the warning and the comment parsing were introduced.
fallthrough devolves to an empty "do {} while (0)" if the compiler
version (any version less than gcc 7) does not support the attribute.
Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
---
Changes since v3:
- This patch is introduce in this version.
Changes since v4: No changes
---
---
xen/include/xen/compiler.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h
index e643e69128..0ec0b4698e 100644
--- a/xen/include/xen/compiler.h
+++ b/xen/include/xen/compiler.h
@@ -33,6 +33,22 @@
#define unreachable() __builtin_unreachable()
#endif
+/*
+ * Add the pseudo keyword 'fallthrough' so case statement blocks
+ * must end with any of these keywords:
+ * break;
+ * fallthrough;
+ * goto <label>;
+ * return [expression];
+ *
+ * gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes
+ */
+#if (!defined(__clang__) && (__GNUC__ >= 7))
+# define fallthrough __attribute__((__fallthrough__))
+#else
+# define fallthrough do {} while (0) /* fallthrough */
+#endif
+
#ifdef __clang__
/* Clang can replace some vars with new automatic ones that go in .data;
* mark all explicit-segment vars 'used' to prevent that. */
--
2.17.1
next prev parent reply other threads:[~2021-01-20 14:58 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 14:52 [PATCH v5 00/10] xen/arm: Add support for SMMUv3 driver Rahul Singh
2021-01-20 14:52 ` [PATCH v5 01/10] xen/arm: smmuv3: Import the SMMUv3 driver from Linux Rahul Singh
2021-01-20 14:52 ` [PATCH v5 02/10] xen/arm: Revert atomic operation related command-queue insertion patch Rahul Singh
2021-01-20 14:52 ` [PATCH v5 03/10] xen/arm: smmuv3: Revert patch related to XArray Rahul Singh
2021-01-20 14:52 ` [PATCH v5 04/10] xen/arm: smmuv3: Remove support for Stage-1 translation on SMMUv3 Rahul Singh
2021-01-20 14:52 ` [PATCH v5 05/10] xen/arm: smmuv3: Remove Linux specific code that is not usable in XEN Rahul Singh
2021-01-20 14:52 ` [PATCH v5 06/10] xen/device-tree: Add dt_property_match_string helper Rahul Singh
2021-01-20 14:52 ` Rahul Singh [this message]
2021-01-20 14:52 ` [PATCH v5 08/10] xen/arm: smmuv3: Use fallthrough pseudo-keyword Rahul Singh
2021-01-20 15:36 ` Bertrand Marquis
2021-01-20 19:56 ` Stefano Stabellini
2021-01-20 14:52 ` [PATCH v5 09/10] xen/arm: smmuv3: Replace linux functions with xen functions Rahul Singh
2021-01-20 14:52 ` [PATCH v5 10/10] xen/arm: smmuv3: Add support for SMMUv3 driver Rahul Singh
2021-01-20 15:35 ` Bertrand Marquis
2021-01-20 20:31 ` Stefano Stabellini
2021-01-21 17:10 ` Rahul Singh
2021-01-21 18:43 ` Julien Grall
2021-01-21 20:28 ` Rahul Singh
2021-01-21 21:20 ` Stefano Stabellini
2021-01-20 21:33 ` Oleksandr
2021-01-21 17:18 ` Rahul Singh
2021-01-21 18:31 ` Julien Grall
2021-01-21 18:50 ` Rahul Singh
2021-01-21 20:19 ` Julien Grall
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