On 02/11/2018 03:36 AM, Markus Armbruster wrote:
In my "build everything" tree, a change to the types in
qapi-schema.json triggers a recompile of about 4800 out of 5100

The previous commit split up qmp-commands.h, qmp-event.h, qmp-visit.h,
qapi-types.h.  Each of these headers still includes all its shards.
Reduce compile time by including just the shards we actually need.

To illustrate the benefits: adding a type to qapi/migration.json now
recompiles some 2300 instead of 4800 objects.  The next commit will
improve it further.

Signed-off-by: Markus Armbruster <arm...@redhat.com>
  backends/cryptodev.c             |  1 -
  backends/hostmem.c               |  3 ++-

How did you determine which shards to include where? Remove all shards, try compiling, and see what fails, then add back in the right includes? Or was it scripted somehow? (Trying to figure out, in case I have to rebase this patch)

+++ b/block/crypto.c
@@ -24,9 +24,9 @@
  #include "sysemu/block-backend.h"
  #include "crypto/block.h"
  #include "qapi/opts-visitor.h"
+#include "qapi/qapi-visit-crypto.h"
  #include "qapi/qmp/qdict.h"
  #include "qapi/qobject-input-visitor.h"
-#include "qapi-visit.h"
  #include "qapi/error.h"

Any rhyme or reason to the resulting include order that I should be looking for (we aren't alphabetical in general, but if your changes were trying to honor a particular pattern among the few affected lines, that's useful to know).

+++ b/scripts/qapi/commands.py

The non-mechanical portion of the patch :)

@@ -241,6 +241,9 @@ class 
def _begin_module(self, name):
          self._visited_ret_types[self._genc] = set()
+        commands = self._module_basename('qapi-commands', name)
+        types = self._module_basename('qapi-types', name)
+        visit = self._module_basename('qapi-visit', name)
  #include "qemu/osdep.h"
  #include "qemu-common.h"
@@ -251,18 +254,17 @@ class 
  #include "qapi/qobject-input-visitor.h"
  #include "qapi/dealloc-visitor.h"
  #include "qapi/error.h"
-#include "%(prefix)sqapi-types.h"
-#include "%(prefix)sqapi-visit.h"
-#include "%(prefix)sqmp-commands.h"
+#include "%(visit)s.h"
+#include "%(commands)s.h"
-                             prefix=self._prefix))
+                             commands=commands, visit=visit))
-#include "%(prefix)sqapi-types.h"
+#include "%(types)s.h"
  #include "qapi/qmp/dispatch.h"
-                             prefix=self._prefix))
+                             types=types))

Makes sense.

The compiler will catch anything we did wrong.

Reviewed-by: Eric Blake <ebl...@redhat.com>

Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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