tools/power/rapl.cpp:844:5 [-Wunreachable-code] code will never be executed
clang reports a -Wunreachable-code warning for sigemptyset() because Darwin's sigemptyset() is a macro that always returns 0. Thus `if (sigemptyset(&sa.sa_mask) < 0)` is always false and `Abort("sigemptyset() failed")` is never called. Linux's sigemptyset() can return 0 or -1. The extra parens around (0) suppress the clang warning.
The "gpu" and "ram" domains aren't supported by all platforms. rapl has a
special constant |kUnsupported_j| to represent this on Linux, but I
accidentally have a minus sign in front of it in several places, which means
that instead of printing "n/a" for unsupported planes we always print "1.0".
I think this happened because I used to hardwire -1 in there and then I later
changed it to a constant but forgot to remove the minus signs.
It sure would be nice to have automated testing for this stuff, but I don't see
how to do it.
The patch removes 455 occurrences of FAIL_ON_WARNINGS from moz.build files, and
adds 78 instances of ALLOW_COMPILER_WARNINGS. About half of those 78 are in
code we control and which should be removable with a little effort.
