Merge remote-tracking branch 'remotes/famz/tags/staging-pull-request' into staging

# gpg: Signature made Thu 08 Feb 2018 01:29:22 GMT
# gpg:                using RSA key CA35624C6A9171C6
# gpg: Good signature from "Fam Zheng <famz@redhat.com>"
# Primary key fingerprint: 5003 7CB7 9706 0F76 F021  AD56 CA35 624C 6A91 71C6

* remotes/famz/tags/staging-pull-request:
  docs: Add docs/devel/testing.rst
  qapi: Add NVMe driver options to the schema
  docs: Add section for NVMe VFIO driver
  block: Move NVMe constants to a separate header
  qemu-img: Map bench buffer
  block/nvme: Implement .bdrv_(un)register_buf
  block: Introduce buf register API
  block: Add VFIO based NVMe driver
  util: Introduce vfio helpers
  stubs: Add stubs for ram block API
  curl: convert to CoQueue
  coroutine-lock: make qemu_co_enter_next thread-safe
  coroutine-lock: convert CoQueue to use QemuLockable
  lockable: add QemuLockable
  test-coroutine: add simple CoMutex test
  docker: change Fedora base image to fedora:27

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 39 insertions, 0 deletions

diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
index 5fcc4f7ec7..2cbe6a4f16 100644
--- a/include/qemu/compiler.h
+++ b/include/qemu/compiler.h
@@ -114,5 +114,44 @@
 #ifndef __has_feature
 #define __has_feature(x) 0 /* compatibility with non-clang compilers */
 #endif
+/* Implement C11 _Generic via GCC builtins.  Example:
+ *
+ *    QEMU_GENERIC(x, (float, sinf), (long double, sinl), sin) (x)
+ *
+ * The first argument is the discriminator.  The last is the default value.
+ * The middle ones are tuples in "(type, expansion)" format.
+ */
+
+/* First, find out the number of generic cases.  */
+#define QEMU_GENERIC(x, ...) \
+    QEMU_GENERIC_(typeof(x), __VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+
+/* There will be extra arguments, but they are not used.  */
+#define QEMU_GENERIC_(x, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, count, ...) \
+    QEMU_GENERIC##count(x, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9)
+
+/* Two more helper macros, this time to extract items from a parenthesized
+ * list.
+ */
+#define QEMU_FIRST_(a, b) a
+#define QEMU_SECOND_(a, b) b
+
+/* ... and a final one for the common part of the "recursion".  */
+#define QEMU_GENERIC_IF(x, type_then, else_)                                   \
+    __builtin_choose_expr(__builtin_types_compatible_p(x,                      \
+                                                       QEMU_FIRST_ type_then), \
+                          QEMU_SECOND_ type_then, else_)
+
+/* CPP poor man's "recursion".  */
+#define QEMU_GENERIC1(x, a0, ...) (a0)
+#define QEMU_GENERIC2(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC1(x, __VA_ARGS__))
+#define QEMU_GENERIC3(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC2(x, __VA_ARGS__))
+#define QEMU_GENERIC4(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC3(x, __VA_ARGS__))
+#define QEMU_GENERIC5(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC4(x, __VA_ARGS__))
+#define QEMU_GENERIC6(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC5(x, __VA_ARGS__))
+#define QEMU_GENERIC7(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC6(x, __VA_ARGS__))
+#define QEMU_GENERIC8(x, a0, ...) QEMU_GENERIC_IF(x, a0, QEMU_GENERIC7(x, __VA_ARGS__))
+#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__))
 
 #endif /* COMPILER_H */