diff --git a/compiler-rt/lib/asan/asan_errors.cpp b/compiler-rt/lib/asan/asan_errors.cpp
--- a/compiler-rt/lib/asan/asan_errors.cpp
+++ b/compiler-rt/lib/asan/asan_errors.cpp
@@ -413,6 +413,7 @@
       is_write(is_write_),
       shadow_val(0) {
   scariness.Clear();
+  bug_descr = "unknown-crash";
   if (access_size) {
     if (access_size <= 9) {
       char desr[] = "?-byte";
@@ -424,7 +425,6 @@
     is_write ? scariness.Scare(20, "write") : scariness.Scare(1, "read");
 
     // Determine the error type.
-    bug_descr = "unknown-crash";
     if (AddrIsInMem(addr)) {
       u8 *shadow_addr = (u8 *)MemToShadow(addr);
       // If we are accessing 16 bytes, look at the second shadow byte.
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h
@@ -39,7 +39,14 @@
 class MemoryMappedSegment {
  public:
   explicit MemoryMappedSegment(char *buff = nullptr, uptr size = 0)
-      : filename(buff), filename_size(size), data_(nullptr) {}
+      : filename(buff),
+        filename_size(size),
+        data_(nullptr),
+        start(0),
+        end(0),
+        offset(0),
+        protection(0),
+        arch(kModuleArchUnknown) {}
   ~MemoryMappedSegment() {}
 
   bool IsReadable() const { return protection & kProtectionRead; }
diff --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -206,7 +206,7 @@
   // The object is 64-byte aligned, because we want hot data to be located
   // in a single cache line if possible (it's accessed in every interceptor).
   ALIGNED(64) LibIgnore libignore;
-  __sanitizer_sigaction sigactions[kSigCount];
+  __sanitizer_sigaction sigactions[kSigCount] = {};
 #if !SANITIZER_APPLE && !SANITIZER_NETBSD
   unsigned finalize_key;
 #endif
diff --git a/compiler-rt/lib/tsan/rtl/tsan_interface_ann.cpp b/compiler-rt/lib/tsan/rtl/tsan_interface_ann.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_interface_ann.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interface_ann.cpp
@@ -70,7 +70,7 @@
 
 struct DynamicAnnContext {
   Mutex mtx;
-  ExpectRace benign;
+  ExpectRace benign = {};
 
   DynamicAnnContext() : mtx(MutexTypeAnnotations) {}
 };
diff --git a/compiler-rt/lib/tsan/rtl/tsan_report.cpp b/compiler-rt/lib/tsan/rtl/tsan_report.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_report.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_report.cpp
@@ -42,7 +42,14 @@
 }
 
 ReportMop::ReportMop()
-    : mset() {
+    : mset()
+    , tid()
+    , addr()
+    , size()
+    , write()
+    , atomic()
+    , external_tag()
+    , stack() {
 }
 
 ReportDesc::~ReportDesc() {
diff --git a/compiler-rt/lib/ubsan/ubsan_diag.h b/compiler-rt/lib/ubsan/ubsan_diag.h
--- a/compiler-rt/lib/ubsan/ubsan_diag.h
+++ b/compiler-rt/lib/ubsan/ubsan_diag.h
@@ -63,14 +63,16 @@
   const SymbolizedStack *SymbolizedLoc;  // Not owned.
 
 public:
-  Location() : Kind(LK_Null) {}
-  Location(SourceLocation Loc) :
-    Kind(LK_Source), SourceLoc(Loc) {}
-  Location(MemoryLocation Loc) :
-    Kind(LK_Memory), MemoryLoc(Loc) {}
+  Location()
+      : Kind(LK_Null), SourceLoc(), MemoryLoc(), SymbolizedLoc(nullptr) {}
+  Location(SourceLocation Loc)
+      : Kind(LK_Source), SourceLoc(Loc), MemoryLoc(), SymbolizedLoc(nullptr) {}
+  Location(MemoryLocation Loc)
+      : Kind(LK_Memory), MemoryLoc(Loc), SourceLoc(), SymbolizedLoc(nullptr) {}
   // SymbolizedStackHolder must outlive Location object.
-  Location(const SymbolizedStackHolder &Stack) :
-    Kind(LK_Symbolized), SymbolizedLoc(Stack.get()) {}
+  Location(const SymbolizedStackHolder &Stack)
+      : Kind(LK_Symbolized), SymbolizedLoc(Stack.get()), SourceLoc(),
+        MemoryLoc() {}
 
   LocationKind getKind() const { return Kind; }