If someone specifies a single target, mixed with O=, the following way:
hubble:~/tip/tools/perf> make O=/tmp/perf util/stat.o
BUILD: Doing 'make -j8' parallel build
gcc -Wbad-function-cast -Wdeclaration-after-statement -Wformat-security -Wformat-y2k [...]
The build might even fail, if a target depends on other targets:
hubble:~/tip/tools/perf> make O=/tmp/perf perf.o
...
perf.c: In function ‘handle_options’:
perf.c:155:21: error: ‘PERF_HTML_PATH’ undeclared (first use in this function)
The correct way to invoke such targets is:
hubble:~/tip/tools/perf> make O=/tmp/perf /tmp/perf/perf.o
BUILD: Doing 'make -j8' parallel build
GEN /tmp/perf/common-cmds.h
CC /tmp/perf/perf.o
But that's unnecessary typing and it's also easy to mistakenly build into the
source directory.
To fix this remove the generic suffix rules and add redirection to $(OUTPUT)
for the most popular .o targets.
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-mk0oiukmhgSbrll6chrPkkqr@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1f7c645ab4