----- Original Message ----- > From: "Thomas Huth" <th...@redhat.com> > To: "Richard Henderson" <r...@twiddle.net>, qemu-devel@nongnu.org, "Paolo > Bonzini" <pbonz...@redhat.com> > Sent: Wednesday, June 21, 2017 3:40:31 AM > Subject: Re: [PATCH v3 8/8] hw/misc/edu: Compile the edu device as common > object > > On 20.06.2017 20:14, Richard Henderson wrote: > > On 06/19/2017 10:52 PM, Thomas Huth wrote: > >> edu.c does not contain any target-specific code, so we can put > >> it into common-obj-y to compile it only once for all targets. > >> > >> Signed-off-by: Thomas Huth <th...@redhat.com> > > > > Isn't CONFIG_EDU defined by the target, via pci.conf? > > Would it ever be set generically? > > This is about Makefiles, not #defines in C sources ... so if I > understand our build-system correctly, the variable is set for the > Makefiles of the targets that use pci.mak. As far as I see, it gets > compiled correctly here. > And we've got plenty of those common-obj-$(CONFIG_xxx) statements > elsewhere in this file (e.g. for CONFIG_PCI_TESTDEV which is also > declared in default-configs/pci.mak), so this is just normal, no problem > here, as far as I can tell.
Yes, the variable is evaluated once during the main directory build, where it comes from config-all-devices.mak. Then it is evaluated again during the per-target build, where it comes from target-specific configuration. config-all-devices.mak should be documented in docs/devel/build-system.txt. Paolo Paolo
