trace: switch to modular code generation for sub-directories

Introduce rules in the top level Makefile that are able to generate
trace.[ch] files in every subdirectory which has a trace-events file.

The top level directory is handled specially, so instead of creating
trace.h, it creates trace-root.h. This allows sub-directories to
include the top level trace-root.h file, without ambiguity wrt to
the trace.g file in the current sub-dir.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170125161417.31949-7-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 55 insertions, 47 deletions

diff --git a/Makefile.objs b/Makefile.objs
index 6abe0b95ff..cf2f387716 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -118,50 +118,58 @@ ivshmem-server-obj-y = contrib/ivshmem-server/
 libvhost-user-obj-y = contrib/libvhost-user/
 
 ######################################################################
-trace-events-y = trace-events
-trace-events-y += util/trace-events
-trace-events-y += crypto/trace-events
-trace-events-y += io/trace-events
-trace-events-y += migration/trace-events
-trace-events-y += block/trace-events
-trace-events-y += hw/block/trace-events
-trace-events-y += hw/block/dataplane/trace-events
-trace-events-y += hw/char/trace-events
-trace-events-y += hw/intc/trace-events
-trace-events-y += hw/net/trace-events
-trace-events-y += hw/virtio/trace-events
-trace-events-y += hw/audio/trace-events
-trace-events-y += hw/misc/trace-events
-trace-events-y += hw/usb/trace-events
-trace-events-y += hw/scsi/trace-events
-trace-events-y += hw/nvram/trace-events
-trace-events-y += hw/display/trace-events
-trace-events-y += hw/input/trace-events
-trace-events-y += hw/timer/trace-events
-trace-events-y += hw/dma/trace-events
-trace-events-y += hw/sparc/trace-events
-trace-events-y += hw/sd/trace-events
-trace-events-y += hw/isa/trace-events
-trace-events-y += hw/mem/trace-events
-trace-events-y += hw/i386/trace-events
-trace-events-y += hw/i386/xen/trace-events
-trace-events-y += hw/9pfs/trace-events
-trace-events-y += hw/ppc/trace-events
-trace-events-y += hw/pci/trace-events
-trace-events-y += hw/s390x/trace-events
-trace-events-y += hw/vfio/trace-events
-trace-events-y += hw/acpi/trace-events
-trace-events-y += hw/arm/trace-events
-trace-events-y += hw/alpha/trace-events
-trace-events-y += hw/xen/trace-events
-trace-events-y += ui/trace-events
-trace-events-y += audio/trace-events
-trace-events-y += net/trace-events
-trace-events-y += target/arm/trace-events
-trace-events-y += target/i386/trace-events
-trace-events-y += target/sparc/trace-events
-trace-events-y += target/s390x/trace-events
-trace-events-y += target/ppc/trace-events
-trace-events-y += qom/trace-events
-trace-events-y += linux-user/trace-events
-trace-events-y += qapi/trace-events
+trace-events-subdirs =
+trace-events-subdirs += util
+trace-events-subdirs += crypto
+trace-events-subdirs += io
+trace-events-subdirs += migration
+trace-events-subdirs += block
+trace-events-subdirs += hw/block
+trace-events-subdirs += hw/block/dataplane
+trace-events-subdirs += hw/char
+trace-events-subdirs += hw/intc
+trace-events-subdirs += hw/net
+trace-events-subdirs += hw/virtio
+trace-events-subdirs += hw/audio
+trace-events-subdirs += hw/misc
+trace-events-subdirs += hw/usb
+trace-events-subdirs += hw/scsi
+trace-events-subdirs += hw/nvram
+trace-events-subdirs += hw/display
+trace-events-subdirs += hw/input
+trace-events-subdirs += hw/timer
+trace-events-subdirs += hw/dma
+trace-events-subdirs += hw/sparc
+trace-events-subdirs += hw/sd
+trace-events-subdirs += hw/isa
+trace-events-subdirs += hw/mem
+trace-events-subdirs += hw/i386
+trace-events-subdirs += hw/i386/xen
+trace-events-subdirs += hw/9pfs
+trace-events-subdirs += hw/ppc
+trace-events-subdirs += hw/pci
+trace-events-subdirs += hw/s390x
+trace-events-subdirs += hw/vfio
+trace-events-subdirs += hw/acpi
+trace-events-subdirs += hw/arm
+trace-events-subdirs += hw/alpha
+trace-events-subdirs += hw/xen
+trace-events-subdirs += ui
+trace-events-subdirs += audio
+trace-events-subdirs += net
+trace-events-subdirs += target/arm
+trace-events-subdirs += target/i386
+trace-events-subdirs += target/sparc
+trace-events-subdirs += target/s390x
+trace-events-subdirs += target/ppc
+trace-events-subdirs += qom
+trace-events-subdirs += linux-user
+trace-events-subdirs += qapi
+
+trace-events-files = $(SRC_PATH)/trace-events $(trace-events-subdirs:%=$(SRC_PATH)/%/trace-events)
+
+trace-obj-y = trace-root.o
+trace-obj-y += $(trace-events-subdirs:%=%/trace.o)
+trace-obj-$(CONFIG_TRACE_UST) += trace-ust-all.o
+trace-obj-$(CONFIG_TRACE_DTRACE) += trace-dtrace-root.o
+trace-obj-$(CONFIG_TRACE_DTRACE) += $(trace-events-subdirs:%=%/trace-dtrace.o)