>Number:         14980
>Category:       toolchain
>Synopsis:       bsd.subdir.mk .WAIT logic has no dependency handling
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Mon Dec 17 11:54:00 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Todd Vierling
>Release:        NetBSD 1.5.x, NetBSD-current 20011217
>Organization:
	duh.org: Pointing out the obvious since 1994.

>Environment:
See "Release"

>Description:

When the .WAIT logic for <bsd.subdir.mk> was added, no provision for any
kind of dependency handling was given.  As a result, you cannot build
a single program that has multiple components, as so:

$ cd src/usr.sbin/dhcp
$ make all-client

In the past, you were able to do just the above, because the recursive
Makefiles would contain lines such as:

all-client: all-common all-minires ...

Since there's now 3 recursive targets that would need this handling (depend,
all, and dependall), this is a little more tricky.  However, this SHOULD
be supported again, as building an individual component gets even more
difficult when the dependencies on in-tree libraries are not known for certain
to the builder.

This also has a big impact on parallelism:  it's possible to add much more
recursion to parallel builds if the dependencies on the build order are
known at subdirectory recursion time.

>How-To-Repeat:
See "Description"

>Fix:

I've had this on my personal to-do list for a long time, but never got
to making a sane scheme for doing these dependencies.  My personal
suggestion would be to provide an extension to the contents of SUBDIR, as
below:

SUBDIR=		common1 common2:common1 common3 prog1:common2:common3 \
		prog2:common1

The result of this should be dependency rules to the effect of:

all-common2: all-common1
depend-common2: depend-common1
dependall-common2: dependall-common1

all-prog1: all-common2 all-common3
depend-prog1: depend-common2 depend-common3
dependall-prog1: dependall-common2 dependall-common3

all-prog2: all-common1
depend-prog2: depend-common1
dependall-prog2: dependall-common1

The builder could then run "make dependall-prog2", for instance, and get
common1 autobuilt (but not common2 and common3).  Note the complete lack
of .WAIT directives; there's *no* need for .WAIT to exist in SUBDIR when
using this scheme.

This scheme is trivial to implement within the <bsd.subdir.mk> .for loop,
but needs peer review before implementation....
>Release-Note:
>Audit-Trail:
>Unformatted: