diff mbox series

[PULL,03/16] qemu/compiler.h: Add qemu_build_not_reached

Message ID 20190925184548.30673-4-richard.henderson@linaro.org
State Accepted
Commit 560e36d5a42e04aa2871c01da6d432592151f7e8
Headers show
Series tcg patch queue | expand

Commit Message

Richard Henderson Sept. 25, 2019, 6:45 p.m. UTC 
Use this as a compile-time assert that a particular
code path is not reachable.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 include/qemu/compiler.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

-- 
2.17.1
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Patch

diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index 20780e722d..7b93c73340 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -221,4 +221,19 @@ 
 #define QEMU_GENERIC9(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC8(x, __VA_ARGS__))
 #define QEMU_GENERIC10(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC9(x, __VA_ARGS__))
 
+/**
+ * qemu_build_not_reached()
+ *
+ * The compiler, during optimization, is expected to prove that a call
+ * to this function cannot be reached and remove it.  If the compiler
+ * supports QEMU_ERROR, this will be reported at compile time; otherwise
+ * this will be reported at link time due to the missing symbol.
+ */
+#ifdef __OPTIMIZE__
+extern void QEMU_NORETURN QEMU_ERROR("code path is reachable")
+    qemu_build_not_reached(void);
+#else
+#define qemu_build_not_reached()  g_assert_not_reached()
+#endif
+
 #endif /* COMPILER_H */