On 18/10/17 22:05 +0100, Jonathan Wakely wrote:
On 18/10/17 16:51 +0200, FX wrote:
Parallel builds of libstdc++ on APFS filesystem (with 1 ns granularity) on
macOS 10.13 often fail (failure rate for “make -j2” to “make -j8” is about 60%
from my own builds and results reported by others):
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81797
This is reproducible with several versions of GNU make.
Changing libstdc++’s makefile to mark install-headers with .NOTPARALLEL fixes
the issue. We've carried that patch in Homebrew (https://brew.sh) for a few
months now, and have had no report of build issues since then.
Bootstrapped and regtested on x86_64-apple-darwin17 (as well as other
platforms). OK to commit?
Could you test using .PHONY: install-headers instead?
That target *is* phony, so telling make that seems sensible.
Presumably the same change is needed for install-freestanding-headers,
since it's very similar.
.NOTPARALLEL ignores any prerequisites, so there's no point listing
install-headers as the prerequisite. Your patch disables parallelism
for all targets in the libstdc++-v3/install directory.
There must be another solution.
