On 10/15/23 23:31, Paolo Bonzini wrote:
Make all items of config-host.h consistent. To keep the
--disable-coroutine-pool
code visible to the compiler, mutuate the IS_ENABLED() macro from Linux.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
include/qemu/compiler.h | 15 +++++++++++++++
meson.build | 2 +-
tests/unit/test-coroutine.c | 2 +-
util/qemu-coroutine.c | 4 ++--
4 files changed, 19 insertions(+), 4 deletions(-)
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index 1109482a000..c797f0d4572 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -212,4 +212,19 @@
# define QEMU_USED
#endif
+/*
+ * Ugly CPP trick that is like "defined FOO", but also works in C
+ * code. Useful to replace #ifdef with "if" statements; assumes
+ * the symbol was defined with Meson's "config.set()", so it is empty
+ * if defined.
+ */
+#define IS_ENABLED(x) IS_EMPTY(x)
+
+#define IS_EMPTY_JUNK_ junk,
+#define IS_EMPTY(value) IS_EMPTY_(IS_EMPTY_JUNK_##value)
+
+/* Expands to either SECOND_ARG(junk, 1, 0) or
SECOND_ARG(IS_EMPTY_JUNK_CONFIG_FOO 1, 0) */
+#define SECOND_ARG(first, second, ...) second
+#define IS_EMPTY_(junk_maybecomma) SECOND_ARG(junk_maybecomma 1, 0)
Clever that.
However, if I had a preference I would go the other way and model after glibc:
Convert everything away from ifdef and always use set01.
Then enable -Wundef so that you catch typos in the usage of these macros.
But this is an improvement of a sort so,
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
r~
