Building in parallel fails

[zorun]

When running make in parallel on a large number of CPU, the build fails:

$ make -j16
Building with optimizations for native
rm -f argon2 bench genkat
rm -f libargon2.so libargon2.a kat-argon2*
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -Wl,-O1,--sort-common,--as-needed,-z,relro src/argon2.c src/core.c src/blake2/blake2b.c src/thread.c src/encoding.c src/opt.c src/run.c -o argon2
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -shared -fPIC -fvisibility=hidden -DA2_VISCTL=1 -Wl,-O1,--sort-common,--as-needed,-z,relro -Wl,-soname,libargon2.so.0 src/argon2.c src/core.c src/blake2/blake2b.c src/thread.c src/encoding.c src/opt.c -o libargon2.so
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -D_FORTIFY_SOURCE=2  -c -o src/argon2.o src/argon2.c
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -D_FORTIFY_SOURCE=2  -c -o src/core.o src/core.c
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -D_FORTIFY_SOURCE=2  -c -o src/blake2/blake2b.o src/blake2/blake2b.c
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -D_FORTIFY_SOURCE=2  -c -o src/thread.o src/thread.c
rm -f testcase
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -D_FORTIFY_SOURCE=2  -c -o src/encoding.o src/encoding.c
rm -rf *.dSYM
cc -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -std=c89 -pthread -O3 -Wall -g -Iinclude -Isrc -march=native -D_FORTIFY_SOURCE=2  -c -o src/opt.o src/opt.c
cd src/ && rm -f *.o
cd src/blake2/ && rm -f *.o
cd kats/ &&  rm -f kat-* diff* run_* make_*
ar rcs libargon2.a src/argon2.o src/core.o src/blake2/blake2b.o src/thread.o src/encoding.o src/opt.o
ar: src/argon2.o: No such file or directory
make: *** [Makefile:124: libargon2.a] Error 1
make: *** Waiting for unfinished jobs....

The issue is that the default target is all: clean $(RUN) libs, which means that clean is executed in parallel with the actual compilation, as demonstrated by the log above.

A solution would be to remove clean from the all target (is it really useful?), or update the README to point to this issue.

[Leont]

Yeah, such a construct is very problematic. It also goes against a central the idea of make: that of doing work only when necessary.

[khovratovich]

Thank you for pointing this out! Please suggest a PR for this.