From: "Morten Brørup" <mb@smartsharesystems.com>
To: dev@dpdk.org, Tyler Retzlaff <roretzla@linux.microsoft.com>,
Thomas Monjalon <thomas@monjalon.net>,
Ferruh Yigit <ferruh.yigit@amd.com>,
Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>,
Ajit Khaparde <ajit.khaparde@broadcom.com>,
Somnath Kotur <somnath.kotur@broadcom.com>,
Bruce Richardson <bruce.richardson@intel.com>,
Gaetan Rivet <grive@u256.net>, Jie Hai <haijie1@huawei.com>,
Long Li <longli@microsoft.com>, Wei Hu <weh@microsoft.com>
Cc: "Morten Brørup" <mb@smartsharesystems.com>
Subject: [PATCH 1/2] eal: add unreachable and precondition hints
Date: Fri, 25 Oct 2024 11:52:22 +0000 [thread overview]
Message-ID: <20241025115223.1230680-2-mb@smartsharesystems.com> (raw)
In-Reply-To: <20241025115223.1230680-1-mb@smartsharesystems.com>
Added two new compiler/optimizer hints:
* The __rte_unreachable hint for use in points in code known never to be
reached.
* The __rte_assume hint for providing information about preconditions the
compiler/optimizer might be unable to figure out by itself.
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
---
lib/eal/include/rte_common.h | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
index c79f9ed319..2f143c87e4 100644
--- a/lib/eal/include/rte_common.h
+++ b/lib/eal/include/rte_common.h
@@ -366,6 +366,16 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
#define __rte_noreturn __attribute__((noreturn))
#endif
+/**
+ * Hint point in program never reached
+ */
+#if defined(RTE_TOOLCHAIN_GCC) || defined(RTE_TOOLCHAIN_CLANG)
+#define __rte_unreachable() __extension__(__builtin_unreachable())
+#else
+/* MSVC or ICC */
+#define __rte_unreachable() __assume(0)
+#endif
+
/**
* Issue a warning in case the function's return value is ignored.
*
@@ -423,6 +433,23 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
#define __rte_cold __attribute__((cold))
#endif
+/**
+ * Hint precondition
+ *
+ * @warning Depending on the compiler, any code in ``condition`` might be executed.
+ * This currently only occurs with GCC prior to version 13.
+ */
+#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 130000)
+#define __rte_assume(condition) __attribute__((assume(condition)))
+#elif defined(RTE_TOOLCHAIN_GCC)
+#define __rte_assume(condition) do { if (!(condition)) __rte_unreachable(); } while (0)
+#elif defined(RTE_TOOLCHAIN_CLANG)
+#define __rte_assume(condition) __extension__(__builtin_assume(condition))
+#else
+/* MSVC or ICC */
+#define __rte_assume(condition) __assume(condition)
+#endif
+
/**
* Disable AddressSanitizer on some code
*/
--
2.43.0
next prev parent reply other threads:[~2024-10-25 11:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-25 11:52 [PATCH 0/2] ethdev: support single queue per port Morten Brørup
2024-10-25 11:52 ` Morten Brørup [this message]
2024-10-25 11:52 ` [PATCH 2/2] drivers/net: " Morten Brørup
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