On 11.12.2009 20:25, Mike Frysinger wrote:
On Thursday 10 December 2009 08:41:07 Daniel Hobi wrote:
During parallel build, the top Makefile spawns multiple sub-makes for targets in cpu/$(CPU). If cpu/$(CPU)/.depend is not present, the sub-makes may end up generating this file simultaneously which leads to corrupted content.
A typical error message is:
.depend:39: *** multiple target patterns. Stop.
This patch serializes the creation of cpu/$(CPU)/.depend by adding cpu/$(CPU) to the depend target in the top Makefile.
seems to happen in lib_$(ARCH)/ too, but in reviewing my logs from the last few months, most parallel .depend failures have indeed been in cpu/$(CPU)/. maybe this is just coincidence though ... perhaps the depend target should walk all subdirs instead of a just random few ones (use LIBS).
The problem with cpu/$(CPU)/ is that the top Makefile builds multiple targets within this directory in parallel - at least start.o and lib$(CPU).a. For all other directories, parallel build should work, since there is only one target per directory.
Can you provide any commit ID where building lib_$(ARCH)/ failed?
Thus, adding all LIBS to the depend target should not make any difference. In order to properly track such dependencies we should switch to non-recursive Makefiles (as seen in Linux) since Recursive Make [is] Considered Harmful[1].
[1] http://miller.emu.id.au/pmiller/books/rmch/
Best regards, Daniel