Make GCC's implicit fall-through static analysis stricter by requiring
the use of the fallthrough attribute statement instead of comments.
This makes the QEMU code style more consistent.
Signed-off-by: Emmanouil Pitsidianakis <manos.pitsidiana...@linaro.org>
---
docs/devel/style.rst | 23 +++++++++++++++++++++++
meson.build | 2 +-
2 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/docs/devel/style.rst b/docs/devel/style.rst
index 2f68b50079..f473dd24e9 100644
--- a/docs/devel/style.rst
+++ b/docs/devel/style.rst
@@ -634,6 +634,29 @@ are still some caveats to beware of
return g_steal_pointer(&foo);
}
+Implicit switch case fall-through
+=================================
+
+The C language allows switch cases to "fall-through" when a "break" statement
+is missing at the end of a case. This, however, introduces ambiguity in the
+code, as it's not always clear if the missing break is intentional or a bug.
+
+As this behaviour allows for bugs we do not allow "implicit fall-through".
+
+In order to identify intentional fall-through cases, we have adopted a
+pseudo-keyword macro 'fallthrough' which expands to gcc's extension
+__attribute__((__fallthrough__)). `Statement Attributes
+<https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html>`_
+
+All switch/case blocks must end in one of:
+
+.. code-block:: c
+
+ break;
+ fallthrough;
+ continue;
+ goto <label>;
+ return [expression];
QEMU Specific Idioms
********************
diff --git a/meson.build b/meson.build
index 79aef19bdc..e8805f0e0c 100644
--- a/meson.build
+++ b/meson.build
@@ -452,7 +452,7 @@ warn_flags = [
'-Wnested-externs',
'-Wendif-labels',
'-Wexpansion-to-defined',
- '-Wimplicit-fallthrough=2',
+ '-Wimplicit-fallthrough=5',
'-Wmissing-format-attribute',
'-Wno-initializer-overrides',
'-Wno-missing-include-dirs',
--
2.39.2
