use -j; all make's in a recursive build cooperate to limit the total
number of jobs, using a token-passing scheme.
The current token passing algorithm is similar to the one implemented
by gmake; there is a single pipe which is inherited through the entire
process hierarchy; tokens are obtained by reading a byte from the
"read end" of the pipe, and are returned by writing them to the "write
end". This exact algorithm is likely to change in the future.
Implementation details:
- Use the new trace facility to allow measurement of the
effectiveness of different token-passing schemes
- Get a token in MakeStartJobs(), return it in Make_Update()
- Eliminate Job_Full() and the jobFull global since they are
redundant with token system.
- Add an "internal" -J option (to pass the token pipe fd's down to
submakes) and a -T option for tracing.
- Change how compatMake is forced so that -j means something when
inherited by submakes.
- When waiting for a token, poll the token-passing pipe as well as
the output pipes of existing jobs.
arguments names on one function being swapped (by a previous author).
Do not do any duplicate suppression when a source list is created. Instead:
* OP_MADE protects against trying to make the source multiple times.
* A new OP_MARK flag is introduced to suppress duplicates while expanding
the .ALLSRC variable and .USE targets.
This turns the O(n^2) insertion into O(n) in most cases.
This is tested with a `make build' and some special test cases.
Firstly, we ignore getenv("PWD") if MAKEOBJDIRPREFIX is set so that we always
get the same value for .CURDIR regardless of how make was invoked.
Second, when executing a command we check if it is ${.MAKE} or ${.MAKE:T}
without a preceeding chdir, if so we insert a chdir(${.CURDIR}) so that
the Makefile will be found by the child make. Note that this behaviour is
dissabled if MAKEOBJDIRPREFIX is not set or if NOCHECKMAKECHDIR is set.
See the comments in main.c for more detail.
With these two changes, one can successfully build usr/src using MAKEOBJDIRPREFIX
allowing the src to be mounted from a CD-ROM.
parents would be get remade, even if children were not really updated
by the commands executed for them. It also makes all the children have
the real modification time set if possible, so it should fix some other
timing weirdnesses...
- collapse childMade and make fields into flags and convert them to bits
CHILDMADE and REMAKE
- introduce FORCE flag that gets set in all the parents of a child that
has no sources and does not exist.
- set oodate if the FORCE flag is set, and not if CHILDMADE
- centralize the RECHECK into Make_Recheck() and use this in make.c and compat.c
- use Make_TimeStamp for all child -> parent timestamp propagations
Make used to only use the search path for nodes that were pure
sources (not targets of other sources). This has been corrected
and now gnu-autoconf generated Makefiles work in directories other
than the source one.
- Suffix transformation rescanning:
Suffix transformations (.c.o:; cc ...) were only recognized in
the past when both suffixes were members of the suffix list.
Thus a sequence like:
.z.b:
echo ${.TARGET}
.SUFFIXES: .z
would cause .z.b: to be inserted as a regular target (and the main
target in this case). Other make programs always add rules that
start with a period in the transformation list and never consider
them as targets. We cannot do that (consider .depend files) so we
resort to scanning the list of the current targets every time a
suffix gets added, and we mutate existing targets that are now
valid transformation rules into transformation rules. If the
transformed target was also the main target, we set the main target
to be the next target in the targets list.
1. ${.*} variables did not get expanded in dependencies.
2. expanded ${.*} variables in .USE dependencies can cause tree
restructuring; handle it.
3. in compat mode, expand .USE before evaluating the list of targets,
instead of doing .USE expansions on demand, because they can cause
tree restructuring.
christos