[asan] add flag coverage_pcs. When false, the coverage is not dumped as PCs. Useful e.g. if the user only needs coverage is bitset

llvm-svn: 225002
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
index e28a6ae..eb69172 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc
@@ -509,6 +509,7 @@
   if (atomic_fetch_add(&dump_once_guard, 1, memory_order_relaxed))
     return;
   CovDumpAsBitSet();
+  if (!common_flags()->coverage_pcs) return;
   uptr size = coverage_data.size();
   InternalMmapVector<u32> offsets(size);
   uptr *vb = coverage_data.data();