The various targets which define versioned machine types have
a bunch of obfuscated macro code for defining unique function
and variable names using string concatenation.
This addes a couple of helpers to improve the clarity of such
code macro.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
include/hw/boards.h | 166 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 166 insertions(+)
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 2fa800f11a..47ca450fca 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -414,6 +414,172 @@ struct MachineState {
struct NumaState *numa_state;
};
+/*
+ * The macros which follow are intended to facilitate the
+ * definition of versioned machine types, using a somewhat
+ * similar pattern across targets:
+ *
+ * #define DEFINE_VIRT_MACHINE_IMPL(latest, ...) \
+ * static void MACHINE_VER_SYM(class_init, virt, __VA_ARGS__)( \
+ * ObjectClass *oc, \
+ * void *data) \
+ * { \
+ * MachineClass *mc = MACHINE_CLASS(oc); \
+ * MACHINE_VER_SYM(options, virt, __VA_ARGS__)(mc); \
+ * mc->desc = "QEMU " MACHINE_VER_STR(__VA_ARGS__) " Virtual Machine"; \
+ * if (latest) { \
+ * mc->alias = "virt"; \
+ * } \
+ * } \
+ * static const TypeInfo MACHINE_VER_SYM(info, virt, __VA_ARGS__) = { \
+ * .name = MACHINE_VER_TYPE_NAME("virt", __VA_ARGS__), \
+ * .parent = TYPE_VIRT_MACHINE, \
+ * .class_init = MACHINE_VER_SYM(class_init, virt, __VA_ARGS__), \
+ * }; \
+ * static void MACHINE_VER_SYM(register, virt, __VA_ARGS__)(void) \
+ * { \
+ * type_register_static(&MACHINE_VER_SYM(info, virt, __VA_ARGS__)); \
+ * } \
+ * type_init(MACHINE_VER_SYM(register, virt, __VA_ARGS__));
+ *
+ * Following this, one (or more) helpers can be added for
+ * whichever scenarios need to be catered for with a machine:
+ *
+ * // Normal 2 digit, marked as latest eg 'virt-9.0'
+ * #define DEFINE_VIRT_MACHINE_LATEST(major, minor) \
+ * DEFINE_VIRT_MACHINE_IMPL(true, major, minor)
+ *
+ * // Normal 2 digit eg 'virt-9.0'
+ * #define DEFINE_VIRT_MACHINE(major, minor) \
+ * DEFINE_VIRT_MACHINE_IMPL(false, major, minor)
+ *
+ * // Bugfix 3 digit eg 'virt-9.0.1'
+ * #define DEFINE_VIRT_MACHINE_BUGFIX(major, minor, micro) \
+ * DEFINE_VIRT_MACHINE_IMPL(false, major, minor, micro)
+ *
+ * // Tagged 2 digit eg 'virt-9.0-extra'
+ * #define DEFINE_VIRT_MACHINE_TAGGED(major, minor, tag) \
+ * DEFINE_VIRT_MACHINE_IMPL(false, major, minor, _, tag)
+ *
+ * // Tagged bugffix 2 digit eg 'virt-9.0.1-extra'
+ * #define DEFINE_VIRT_MACHINE_TAGGED(major, minor, micro, tag) \
+ * DEFINE_VIRT_MACHINE_IMPL(false, major, minor, micro, _, tag)
+ */
+
+#define _MACHINE_VER_PICK(x1, x2, x3, x4, x5, x6, ...) x6
+
+/*
+ * Construct a human targetted machine version string.
+ *
+ * Can be invoked with various signatures
+ *
+ * MACHINE_VER_STR(sym, prefix, major, minor)
+ * MACHINE_VER_STR(sym, prefix, major, minor, micro)
+ * MACHINE_VER_STR(sym, prefix, major, minor, _, tag)
+ * MACHINE_VER_STR(sym, prefix, major, minor, micro, _, tag)
+ *
+ * Respectively emitting symbols with the format
+ *
+ * "{major}.{minor}"
+ * "{major}.{minor}-{tag}"
+ * "{major}.{minor}.{micro}"
+ * "{major}.{minor}.{micro}-{tag}"
+ */
+#define _MACHINE_VER_STR2(major, minor) \
+ #major "." #minor
+
+#define _MACHINE_VER_STR3(major, minor, micro) \
+ #major "." #minor "." #micro
+
+#define _MACHINE_VER_STR4(major, minor, _unused_, tag) \
+ #major "." #minor "-" #tag
+
+#define _MACHINE_VER_STR5(major, minor, micro, _unused_, tag) \
+ #major "." #minor "." #micro "-" #tag
+
+#define MACHINE_VER_STR(...) \
+ _MACHINE_VER_PICK(__VA_ARGS__, \
+ _MACHINE_VER_STR5, \
+ _MACHINE_VER_STR4, \
+ _MACHINE_VER_STR3, \
+ _MACHINE_VER_STR2) (__VA_ARGS__)
+
+
+/*
+ * Construct a QAPI type name for a versioned machine
+ * type
+ *
+ * Can be invoked with various signatures
+ *
+ * MACHINE_VER_TYPE_NAME(prefix, major, minor)
+ * MACHINE_VER_TYPE_NAME(prefix, major, minor, micro)
+ * MACHINE_VER_TYPE_NAME(prefix, major, minor, _, tag)
+ * MACHINE_VER_TYPE_NAME(prefix, major, minor, micro, _, tag)
+ *
+ * Respectively emitting symbols with the format
+ *
+ * "{prefix}-{major}.{minor}"
+ * "{prefix}-{major}.{minor}.{micro}"
+ * "{prefix}-{major}.{minor}-{tag}"
+ * "{prefix}-{major}.{minor}.{micro}-{tag}"
+ */
+#define _MACHINE_VER_TYPE_NAME2(prefix, major, minor) \
+ prefix "-" #major "." #minor TYPE_MACHINE_SUFFIX
+
+#define _MACHINE_VER_TYPE_NAME3(prefix, major, minor, micro) \
+ prefix "-" #major "." #minor "." #micro TYPE_MACHINE_SUFFIX
+
+#define _MACHINE_VER_TYPE_NAME4(prefix, major, minor, _unused_, tag) \
+ prefix "-" #major "." #minor "-" #tag TYPE_MACHINE_SUFFIX
+
+#define _MACHINE_VER_TYPE_NAME5(prefix, major, minor, micro, _unused_, tag) \
+ prefix "-" #major "." #minor "." #micro "-" #tag TYPE_MACHINE_SUFFIX
+
+#define MACHINE_VER_TYPE_NAME(prefix, ...) \
+ _MACHINE_VER_PICK(__VA_ARGS__, \
+ _MACHINE_VER_TYPE_NAME5, \
+ _MACHINE_VER_TYPE_NAME4, \
+ _MACHINE_VER_TYPE_NAME3, \
+ _MACHINE_VER_TYPE_NAME2) (prefix, __VA_ARGS__)
+
+/*
+ * Construct a name for a versioned machine type that is
+ * suitable for use as a C symbol (function/variable/etc).
+ *
+ * Can be invoked with various signatures
+ *
+ * MACHINE_VER_SYM(sym, prefix, major, minor)
+ * MACHINE_VER_SYM(sym, prefix, major, minor, micro)
+ * MACHINE_VER_SYM(sym, prefix, major, minor, _, tag)
+ * MACHINE_VER_SYM(sym, prefix, major, minor, micro, _, tag)
+ *
+ * Respectively emitting symbols with the format
+ *
+ * {prefix}_machine_{major}_{minor}_{sym}
+ * {prefix}_machine_{major}_{minor}_{micro}_{sym}
+ * {prefix}_machine_{major}_{minor}_{tag}_{sym}
+ * {prefix}_machine_{major}_{minor}_{micro}_{tag}_{sym}
+ */
+#define _MACHINE_VER_SYM2(sym, prefix, major, minor) \
+ prefix ## _machine_ ## major ## _ ## minor ## _ ## sym
+
+#define _MACHINE_VER_SYM3(sym, prefix, major, minor, micro) \
+ prefix ## _machine_ ## major ## _ ## minor ## _ ## micro ## _ ## sym
+
+#define _MACHINE_VER_SYM4(sym, prefix, major, minor, _unused_, tag) \
+ prefix ## _machine_ ## major ## _ ## minor ## _ ## tag ## _ ## sym
+
+#define _MACHINE_VER_SYM5(sym, prefix, major, minor, micro, _unused_, tag) \
+ prefix ## _machine_ ## major ## _ ## minor ## _ ## micro ## _ ## tag ## _ ## sym
+
+#define MACHINE_VER_SYM(sym, prefix, ...) \
+ _MACHINE_VER_PICK(__VA_ARGS__, \
+ _MACHINE_VER_SYM5, \
+ _MACHINE_VER_SYM4, \
+ _MACHINE_VER_SYM3, \
+ _MACHINE_VER_SYM2) (sym, prefix, __VA_ARGS__)
+
+
#define DEFINE_MACHINE(namestr, machine_initfn) \
static void machine_initfn##_class_init(ObjectClass *oc, void *data) \
{ \
--
2.43.0
On Wed, May 01, 2024 at 07:27:46PM +0100, Daniel P. Berrangé wrote:
> The various targets which define versioned machine types have
> a bunch of obfuscated macro code for defining unique function
> and variable names using string concatenation.
>
> This addes a couple of helpers to improve the clarity of such
> code macro.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
> include/hw/boards.h | 166 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 166 insertions(+)
>
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 2fa800f11a..47ca450fca 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -414,6 +414,172 @@ struct MachineState {
> struct NumaState *numa_state;
> };
>
> +/*
> + * The macros which follow are intended to facilitate the
> + * definition of versioned machine types, using a somewhat
> + * similar pattern across targets:
> + *
> + * #define DEFINE_VIRT_MACHINE_IMPL(latest, ...) \
> + * static void MACHINE_VER_SYM(class_init, virt, __VA_ARGS__)( \
> + * ObjectClass *oc, \
> + * void *data) \
> + * { \
> + * MachineClass *mc = MACHINE_CLASS(oc); \
> + * MACHINE_VER_SYM(options, virt, __VA_ARGS__)(mc); \
Nice to include example usage of the macros. __VA_ARGS__ is getting
expanded quite a few times here, but I don't see that as being too
much of a problem.
> + * // Normal 2 digit eg 'virt-9.0'
> + * #define DEFINE_VIRT_MACHINE(major, minor) \
> + * DEFINE_VIRT_MACHINE_IMPL(false, major, minor)
> + *
> + * // Bugfix 3 digit eg 'virt-9.0.1'
Inconsistent on whether you are using one or two spaces before 'eg'.
> +
> +#define _MACHINE_VER_PICK(x1, x2, x3, x4, x5, x6, ...) x6
This helper macro is powerful; it may be worth a short comment, maybe
along the lines of:
/* Helper macro used to pick the right macro name based on the number
* of extra arguments passed to the containing macro; usage:
*
* _MACHINE_VER_PICK(__VA_ARGS__, \
* MACRO_FOR_5_ARGS, \
* MACRO_FOR_4_ARGS, \
* MACRO_FOR_3_ARGS, \
* MACRO_FOR_2_ARGS)(optional prefix args, __VA_ARGS__)
*/
But once understood, I see it comes in handy in several places below.
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization: qemu.org | libguestfs.org
On Thu, May 02, 2024 at 09:57:21AM -0500, Eric Blake wrote:
> On Wed, May 01, 2024 at 07:27:46PM +0100, Daniel P. Berrangé wrote:
> > The various targets which define versioned machine types have
> > a bunch of obfuscated macro code for defining unique function
> > and variable names using string concatenation.
> >
> > This addes a couple of helpers to improve the clarity of such
> > code macro.
> >
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> > include/hw/boards.h | 166 ++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 166 insertions(+)
> >
> > diff --git a/include/hw/boards.h b/include/hw/boards.h
> > index 2fa800f11a..47ca450fca 100644
> > --- a/include/hw/boards.h
> > +++ b/include/hw/boards.h
> > @@ -414,6 +414,172 @@ struct MachineState {
> > struct NumaState *numa_state;
> > };
> >
> > +/*
> > + * The macros which follow are intended to facilitate the
> > + * definition of versioned machine types, using a somewhat
> > + * similar pattern across targets:
> > + *
> > + * #define DEFINE_VIRT_MACHINE_IMPL(latest, ...) \
> > + * static void MACHINE_VER_SYM(class_init, virt, __VA_ARGS__)( \
> > + * ObjectClass *oc, \
> > + * void *data) \
> > + * { \
> > + * MachineClass *mc = MACHINE_CLASS(oc); \
> > + * MACHINE_VER_SYM(options, virt, __VA_ARGS__)(mc); \
>
> Nice to include example usage of the macros. __VA_ARGS__ is getting
> expanded quite a few times here, but I don't see that as being too
> much of a problem.
>
> > + * // Normal 2 digit eg 'virt-9.0'
> > + * #define DEFINE_VIRT_MACHINE(major, minor) \
> > + * DEFINE_VIRT_MACHINE_IMPL(false, major, minor)
> > + *
> > + * // Bugfix 3 digit eg 'virt-9.0.1'
>
> Inconsistent on whether you are using one or two spaces before 'eg'.
Will fix
>
> > +
> > +#define _MACHINE_VER_PICK(x1, x2, x3, x4, x5, x6, ...) x6
>
> This helper macro is powerful; it may be worth a short comment, maybe
> along the lines of:
>
> /* Helper macro used to pick the right macro name based on the number
> * of extra arguments passed to the containing macro; usage:
> *
> * _MACHINE_VER_PICK(__VA_ARGS__, \
> * MACRO_FOR_5_ARGS, \
> * MACRO_FOR_4_ARGS, \
> * MACRO_FOR_3_ARGS, \
> * MACRO_FOR_2_ARGS)(optional prefix args, __VA_ARGS__)
> */
Yes, will add something like this
>
> But once understood, I see it comes in handy in several places below.
>
> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> --
> Eric Blake, Principal Software Engineer
> Red Hat, Inc.
> Virtualization: qemu.org | libguestfs.org
>
With regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
On 02/05/2024 16.57, Eric Blake wrote: > On Wed, May 01, 2024 at 07:27:46PM +0100, Daniel P. Berrangé wrote: >> The various targets which define versioned machine types have >> a bunch of obfuscated macro code for defining unique function >> and variable names using string concatenation. >> >> This addes a couple of helpers to improve the clarity of such >> code macro. >> >> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> >> --- ... >> + * // Normal 2 digit eg 'virt-9.0' >> + * #define DEFINE_VIRT_MACHINE(major, minor) \ >> + * DEFINE_VIRT_MACHINE_IMPL(false, major, minor) >> + * >> + * // Bugfix 3 digit eg 'virt-9.0.1' > > Inconsistent on whether you are using one or two spaces before 'eg'. While you're at it, maybe also better spell it with dots: e.g. Thomas
© 2016 - 2025 Red Hat, Inc.