Summary:
Adds interception of sigprocmask and pthread_sigmask to esan so that the
working set tool can prevent SIGSEGV from being blocked. A blocked SIGSEGV
results in crashes due to our lazy shadow page allocation scheme.
Adds new sanitizer helper functions internal_sigemptyset and
internal_sigismember.
Adds a test to workingset-signal-posix.cpp.
Reviewers: aizatsky
Subscribers: vitalybuka, zhaoqin, kcc, eugenis, llvm-commits, kubabrecka
Differential Revision: http://reviews.llvm.org/D22063
llvm-svn: 274672
34913f3beb