Re: [PATCH v5 05/62] qapi: add type-infos generator

[Markus Armbruster <armbru@redhat.com>]

Marc-André Lureau <marcandre.lureau@redhat.com> writes:

> New QAPISchemaGenTypeInfoVisitor produces per-module
> qapi-type-infos-*.h/c files. Each file declares QAPITypeInfo constants
> pairing the QAPI type name with its masked introspection name.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Per-module is a bit problematic due to type masking.

To create a QOM property of QAPI type, we need the declaration of its
QAPITypeInfo, and we include the modular type-infos header to get it.

For instance, crypto/secret_common.c includes
qapi/qapi-type-infos-crypto.h for QCryptoSecretFormat_type_info.  Adding
or removing types in qapi/crypto.json will change
qapi/qapi-type-infos-crypto.h and trigger recompilation of
crypto/secret_common.c.  Adding or removing types elswhere won't.  Good.

However, messing with types *anywhere* almost always changes the masked
names *everywhere*, triggering recompilation of all qapi/*type-infos*.c.
Not so good.

A slow build is commonly death by a thousand cuts.  This is yet another
cut.  I'm sure we could figure out how to avoid it, but the series is
big and I don't want to delay it more than I have to.  Let's note the
issue in the commit message.

Aside: existing qapi/qapi-introspect.c is monolithic, which is
differently problematic.  Only qapi/qapi-introspect.c changes.  Good.
It's ~1.2MiB.  Not so good.

> ---
>  docs/devel/qapi-code-gen.rst |  92 +++++++++++++++++++++++
>  meson.build                  |   1 +
>  scripts/qapi/backend.py      |   2 +
>  scripts/qapi/type_infos.py   | 175 +++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 270 insertions(+)
>
> diff --git a/docs/devel/qapi-code-gen.rst b/docs/devel/qapi-code-gen.rst
> index b697aab930d1..69d5c4af9874 100644
> --- a/docs/devel/qapi-code-gen.rst
> +++ b/docs/devel/qapi-code-gen.rst
> @@ -1250,6 +1250,9 @@ JSON array of strings.
>  To examine a type, start with a command or event using it, then follow
>  references by name.
>  
> +.. TODO document QOM introspection (qom-list, qom-list-properties,
> +   qom-get) and how it relates to QAPI type information.
> +
>  .. TODO document QOM introspection (qom-list, qom-list-properties,
>     qom-get) and how it relates to QAPI type information.
>  

Duplicate.  The first copy is from PATCH 04.  I believe it's an accident
there.

Out of time for today, intend to look at the remainder as soon as I can.

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