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Re: [Qemu-devel] [PATCH for-4.0 v7 01/27] qapi: make sure osdep.h is inc
Re: [Qemu-devel] [PATCH for-4.0 v7 01/27] qapi: make sure osdep.h is included in type headers
Tue, 11 Dec 2018 19:47:45 +0400
On Mon, Dec 10, 2018 at 5:28 PM Markus Armbruster <address@hidden> wrote:
> Marc-André Lureau <address@hidden> writes:
> > Hi
> > On Mon, Dec 10, 2018 at 1:52 PM Markus Armbruster <address@hidden> wrote:
> >> Marc-André Lureau <address@hidden> writes:
> >> > Now that the schema can be configured, it is crucial that all types
> >> > are configured the same. Make sure config-host.h is included, by
> >> > checking osdep.h inclusion. The build-sys tracks the dependency and
> >> > rebuilds the types if the configuration changed.
> >> >
> >> > Signed-off-by: Marc-André Lureau <address@hidden>
> >> > ---
> >> > scripts/qapi/types.py | 3 +++
> >> > 1 file changed, 3 insertions(+)
> >> >
> >> > diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
> >> > index fd7808103c..3bb9cb6d47 100644
> >> > --- a/scripts/qapi/types.py
> >> > +++ b/scripts/qapi/types.py
> >> > @@ -201,6 +201,9 @@ class
> >> > QAPISchemaGenTypeVisitor(QAPISchemaModularCVisitor):
> >> > ''',
> >> > types=types, visit=visit))
> >> > self._genh.preamble_add(mcgen('''
> >> > +#ifndef QEMU_OSDEP_H
> >> > +#error Please include osdep.h first!
> >> > +#endif
> >> > #include "qapi/qapi-builtin-types.h"
> >> > '''))
> >> I understand why you propose this patch. The QAPI-generated headers use
> >> #ifdef CONFIG_FOO. The configuration header "qemu/osdep.h" must be
> >> consistently included before the generated headers, or else you end up
> >> with nasty bugs, such as the same enum having different values in
> >> different .o, or the same struct having a different layout.
> >> But this applies to *all* headers that use #ifdef. Why check it here,
> >> but not there? What makes the QAPI-generated headers special?
> > It's the discussion about #if in headers (and enums in particular)
> > that started this. We want to make sure all compilation units share
> > the same data structure/ABI. I proposed to include osdep.h in qapi
> > headers, but that was rejected.
> > The warning is a different approach. I agree it could apply to all
> > headers. Do you think I should update all headers as well?
> That would replace the rule 'all .c files must include "qemu/osdep.h"
> first' by 'all .h files must check "qemu/osdep.h" has been included
> already', which is not an improvement.
That would be an improvement since headers may also be impacted by osdep.h
Alternatively, why not use -include ?
> All we have right now to help with enforcing our osdep.h rule is
> scripts/clean-includes. We run it periodically to fix rule breakers.
> It's manual, because we have a few .c files in the tree where the rule
> doesn't apply, and the script doesn't know about them. Fixable, I
> guess. Most recent run:
> Subject: [PATCH] Clean up includes
> Message-Id: <address@hidden>
> The obvious improvement would be flagging rule breakers before they get
> checkpatch.pl could flag patches adding .c files that don't include
> "qemu/osdep.h" first. The "first" part might be a bit annoying to code.
> The "adding files" part already exists: checkpatch.pl warns when you add
> a file without updating MAINTAINERS.
> checkpatch.pl could also flag patches removing #include "qemu/osdep.h".
> Other projects use a syntax-check make target to check sources. If we
> decide we like that better than checkpatch.pl for some checks, we can do
[Qemu-devel] [PATCH for-4.0 v7 02/27] qapi: do not define enumeration value explicitly, Marc-André Lureau, 2018/12/08
[Qemu-devel] [PATCH for-4.0 v7 03/27] qapi: rename QAPISchemaEnumType.values to .members, Marc-André Lureau, 2018/12/08
[Qemu-devel] [PATCH for-4.0 v7 04/27] qapi: change enum visitor and gen_enum* to take QAPISchemaMember, Marc-André Lureau, 2018/12/08
[Qemu-devel] [PATCH for-4.0 v7 05/27] tests: print enum type members more like object type members, Marc-André Lureau, 2018/12/08
[Qemu-devel] [PATCH for-4.0 v7 06/27] qapi: factor out checking for keys, Marc-André Lureau, 2018/12/08