[PATCH] [msan] Unpoison siginfo_t and ucontext_t in signal handlers.

[Alexey Samsonov]

  LGTM with a few minor nits


================
Comment at: lib/msan/tests/msan_test.cc:1007
@@ +1006,3 @@
+  sigaction(SIGPROF, &act, 0);
+  assert(cnt == 2);
+}
----------------
EXPECT_EQ(2, cnt)? 

================
Comment at: lib/msan/tests/msan_test.cc:1010
@@ +1009,3 @@
+
+}
+
----------------
}  // namespace

================
Comment at: lib/msan/msan_interceptors.cc:827
@@ -826,2 +826,3 @@
 
-INTERCEPTOR(int, sigaction, int signum, const void *act, void *oldact) {
+const int MAX_SIGNALS = 1024;
+static uptr sigactions[MAX_SIGNALS];
----------------
const int kMaxSignals = 1024;


http://llvm-reviews.chandlerc.com/D611