diff --git a/compiler-rt/lib/scudo/standalone/combined.h b/compiler-rt/lib/scudo/standalone/combined.h
--- a/compiler-rt/lib/scudo/standalone/combined.h
+++ b/compiler-rt/lib/scudo/standalone/combined.h
@@ -944,8 +944,8 @@
   static const sptr MemTagAllocationTraceIndex = -2;
   static const sptr MemTagAllocationTidIndex = -1;
 
-  u32 Cookie;
-  u32 QuarantineMaxChunkSize;
+  u32 Cookie = 0;
+  u32 QuarantineMaxChunkSize = 0;
 
   GlobalStats Stats;
   PrimaryT Primary;
@@ -977,7 +977,7 @@
 #endif
     Entry Entries[NumEntries];
   };
-  AllocationRingBuffer RingBuffer;
+  AllocationRingBuffer RingBuffer = {};
 
   // The following might get optimized out by the compiler.
   NOINLINE void performSanityChecks() {
diff --git a/compiler-rt/lib/scudo/standalone/internal_defs.h b/compiler-rt/lib/scudo/standalone/internal_defs.h
--- a/compiler-rt/lib/scudo/standalone/internal_defs.h
+++ b/compiler-rt/lib/scudo/standalone/internal_defs.h
@@ -48,6 +48,15 @@
 #define USED __attribute__((used))
 #define NOEXCEPT noexcept
 
+#if defined(__has_attribute)
+#if __has_attribute(require_constant_initialization)
+#define SCUDO_REQUIRE_CONSTANT_INITIALIZATION                                  \
+  __attribute__((__require_constant_initialization__))
+#else
+#define SCUDO_REQUIRE_CONSTANT_INITIALIZATION
+#endif
+#endif
+
 namespace scudo {
 
 typedef unsigned long uptr;
diff --git a/compiler-rt/lib/scudo/standalone/list.h b/compiler-rt/lib/scudo/standalone/list.h
--- a/compiler-rt/lib/scudo/standalone/list.h
+++ b/compiler-rt/lib/scudo/standalone/list.h
@@ -57,9 +57,9 @@
   void checkConsistency() const;
 
 protected:
-  uptr Size;
-  T *First;
-  T *Last;
+  uptr Size = 0;
+  T *First = nullptr;
+  T *Last = nullptr;
 };
 
 template <class T> void IntrusiveList<T>::checkConsistency() const {
diff --git a/compiler-rt/lib/scudo/standalone/local_cache.h b/compiler-rt/lib/scudo/standalone/local_cache.h
--- a/compiler-rt/lib/scudo/standalone/local_cache.h
+++ b/compiler-rt/lib/scudo/standalone/local_cache.h
@@ -138,9 +138,9 @@
     uptr ClassSize;
     CompactPtrT Chunks[2 * TransferBatch::MaxNumCached];
   };
-  PerClass PerClassArray[NumClasses];
+  PerClass PerClassArray[NumClasses] = {};
   LocalStats Stats;
-  SizeClassAllocator *Allocator;
+  SizeClassAllocator *Allocator = nullptr;
 
   ALWAYS_INLINE void initCacheMaybe(PerClass *C) {
     if (LIKELY(C->MaxCount))
diff --git a/compiler-rt/lib/scudo/standalone/mutex.h b/compiler-rt/lib/scudo/standalone/mutex.h
--- a/compiler-rt/lib/scudo/standalone/mutex.h
+++ b/compiler-rt/lib/scudo/standalone/mutex.h
@@ -48,9 +48,9 @@
   static constexpr u8 NumberOfYields = 8U;
 
 #if SCUDO_LINUX
-  atomic_u32 M;
+  atomic_u32 M = {};
 #elif SCUDO_FUCHSIA
-  sync_mutex_t M;
+  sync_mutex_t M = {};
 #endif
 
   void lockSlow();
diff --git a/compiler-rt/lib/scudo/standalone/options.h b/compiler-rt/lib/scudo/standalone/options.h
--- a/compiler-rt/lib/scudo/standalone/options.h
+++ b/compiler-rt/lib/scudo/standalone/options.h
@@ -44,9 +44,8 @@
 }
 
 struct AtomicOptions {
-  atomic_u32 Val;
+  atomic_u32 Val = {};
 
-public:
   Options load() const { return Options{atomic_load_relaxed(&Val)}; }
 
   void clear(OptionBit Opt) {
diff --git a/compiler-rt/lib/scudo/standalone/primary32.h b/compiler-rt/lib/scudo/standalone/primary32.h
--- a/compiler-rt/lib/scudo/standalone/primary32.h
+++ b/compiler-rt/lib/scudo/standalone/primary32.h
@@ -489,17 +489,17 @@
     return TotalReleasedBytes;
   }
 
-  SizeClassInfo SizeClassInfoArray[NumClasses];
+  SizeClassInfo SizeClassInfoArray[NumClasses] = {};
 
   // Track the regions in use, 0 is unused, otherwise store ClassId + 1.
-  ByteMap PossibleRegions;
-  atomic_s32 ReleaseToOsIntervalMs;
+  ByteMap PossibleRegions = {};
+  atomic_s32 ReleaseToOsIntervalMs = {};
   // Unless several threads request regions simultaneously from different size
   // classes, the stash rarely contains more than 1 entry.
   static constexpr uptr MaxStashedRegions = 4;
   HybridMutex RegionsStashMutex;
-  uptr NumberOfStashedRegions;
-  uptr RegionsStash[MaxStashedRegions];
+  uptr NumberOfStashedRegions = 0;
+  uptr RegionsStash[MaxStashedRegions] = {};
 };
 
 } // namespace scudo
diff --git a/compiler-rt/lib/scudo/standalone/primary64.h b/compiler-rt/lib/scudo/standalone/primary64.h
--- a/compiler-rt/lib/scudo/standalone/primary64.h
+++ b/compiler-rt/lib/scudo/standalone/primary64.h
@@ -285,24 +285,24 @@
   struct UnpaddedRegionInfo {
     HybridMutex Mutex;
     SinglyLinkedList<TransferBatch> FreeList;
-    uptr RegionBeg;
-    RegionStats Stats;
-    u32 RandState;
-    uptr MappedUser;    // Bytes mapped for user memory.
-    uptr AllocatedUser; // Bytes allocated for user memory.
-    MapPlatformData Data;
-    ReleaseToOsInfo ReleaseInfo;
-    bool Exhausted;
+    uptr RegionBeg = 0;
+    RegionStats Stats = {};
+    u32 RandState = 0;
+    uptr MappedUser = 0;    // Bytes mapped for user memory.
+    uptr AllocatedUser = 0; // Bytes allocated for user memory.
+    MapPlatformData Data = {};
+    ReleaseToOsInfo ReleaseInfo = {};
+    bool Exhausted = false;
   };
   struct RegionInfo : UnpaddedRegionInfo {
     char Padding[SCUDO_CACHE_LINE_SIZE -
-                 (sizeof(UnpaddedRegionInfo) % SCUDO_CACHE_LINE_SIZE)];
+                 (sizeof(UnpaddedRegionInfo) % SCUDO_CACHE_LINE_SIZE)] = {};
   };
   static_assert(sizeof(RegionInfo) % SCUDO_CACHE_LINE_SIZE == 0, "");
 
-  uptr PrimaryBase;
-  MapPlatformData Data;
-  atomic_s32 ReleaseToOsIntervalMs;
+  uptr PrimaryBase = 0;
+  MapPlatformData Data = {};
+  atomic_s32 ReleaseToOsIntervalMs = {};
   alignas(SCUDO_CACHE_LINE_SIZE) RegionInfo RegionInfoArray[NumClasses];
 
   RegionInfo *getRegionInfo(uptr ClassId) {
diff --git a/compiler-rt/lib/scudo/standalone/quarantine.h b/compiler-rt/lib/scudo/standalone/quarantine.h
--- a/compiler-rt/lib/scudo/standalone/quarantine.h
+++ b/compiler-rt/lib/scudo/standalone/quarantine.h
@@ -161,7 +161,7 @@
 
 private:
   SinglyLinkedList<QuarantineBatch> List;
-  atomic_uptr Size;
+  atomic_uptr Size = {};
 
   void addToSize(uptr add) { atomic_store_relaxed(&Size, getSize() + add); }
   void subFromSize(uptr sub) { atomic_store_relaxed(&Size, getSize() - sub); }
@@ -246,9 +246,9 @@
   alignas(SCUDO_CACHE_LINE_SIZE) HybridMutex CacheMutex;
   CacheT Cache;
   alignas(SCUDO_CACHE_LINE_SIZE) HybridMutex RecycleMutex;
-  atomic_uptr MinSize;
-  atomic_uptr MaxSize;
-  alignas(SCUDO_CACHE_LINE_SIZE) atomic_uptr MaxCacheSize;
+  atomic_uptr MinSize = {};
+  atomic_uptr MaxSize = {};
+  alignas(SCUDO_CACHE_LINE_SIZE) atomic_uptr MaxCacheSize = {};
 
   void NOINLINE recycle(uptr MinSize, Callback Cb) {
     CacheT Tmp;
diff --git a/compiler-rt/lib/scudo/standalone/secondary.h b/compiler-rt/lib/scudo/standalone/secondary.h
--- a/compiler-rt/lib/scudo/standalone/secondary.h
+++ b/compiler-rt/lib/scudo/standalone/secondary.h
@@ -377,16 +377,16 @@
   }
 
   HybridMutex Mutex;
-  u32 EntriesCount;
-  u32 QuarantinePos;
-  atomic_u32 MaxEntriesCount;
-  atomic_uptr MaxEntrySize;
-  u64 OldestTime;
-  u32 IsFullEvents;
-  atomic_s32 ReleaseToOsIntervalMs;
-
-  CachedBlock Entries[Config::SecondaryCacheEntriesArraySize];
-  CachedBlock Quarantine[Config::SecondaryCacheQuarantineSize];
+  u32 EntriesCount = 0;
+  u32 QuarantinePos = 0;
+  atomic_u32 MaxEntriesCount = {};
+  atomic_uptr MaxEntrySize = {};
+  u64 OldestTime = 0;
+  u32 IsFullEvents = 0;
+  atomic_s32 ReleaseToOsIntervalMs = {};
+
+  CachedBlock Entries[Config::SecondaryCacheEntriesArraySize] = {};
+  CachedBlock Quarantine[Config::SecondaryCacheQuarantineSize] = {};
 };
 
 template <typename Config> class MapAllocator {
@@ -451,11 +451,11 @@
 
   HybridMutex Mutex;
   DoublyLinkedList<LargeBlock::Header> InUseBlocks;
-  uptr AllocatedBytes;
-  uptr FreedBytes;
-  uptr LargestSize;
-  u32 NumberOfAllocs;
-  u32 NumberOfFrees;
+  uptr AllocatedBytes = 0;
+  uptr FreedBytes = 0;
+  uptr LargestSize = 0;
+  u32 NumberOfAllocs = 0;
+  u32 NumberOfFrees = 0;
   LocalStats Stats;
 };
 
diff --git a/compiler-rt/lib/scudo/standalone/stack_depot.h b/compiler-rt/lib/scudo/standalone/stack_depot.h
--- a/compiler-rt/lib/scudo/standalone/stack_depot.h
+++ b/compiler-rt/lib/scudo/standalone/stack_depot.h
@@ -40,7 +40,7 @@
 
 class StackDepot {
   HybridMutex RingEndMu;
-  u32 RingEnd;
+  u32 RingEnd = 0;
 
   // This data structure stores a stack trace for each allocation and
   // deallocation when stack trace recording is enabled, that may be looked up
@@ -70,7 +70,7 @@
 #endif
   static const uptr TabSize = 1 << TabBits;
   static const uptr TabMask = TabSize - 1;
-  atomic_u32 Tab[TabSize];
+  atomic_u32 Tab[TabSize] = {};
 
 #ifdef SCUDO_FUZZ
   static const uptr RingBits = 4;
@@ -79,7 +79,7 @@
 #endif
   static const uptr RingSize = 1 << RingBits;
   static const uptr RingMask = RingSize - 1;
-  atomic_u64 Ring[RingSize];
+  atomic_u64 Ring[RingSize] = {};
 
 public:
   // Insert hash of the stack trace [Begin, End) into the stack depot, and
diff --git a/compiler-rt/lib/scudo/standalone/stats.h b/compiler-rt/lib/scudo/standalone/stats.h
--- a/compiler-rt/lib/scudo/standalone/stats.h
+++ b/compiler-rt/lib/scudo/standalone/stats.h
@@ -46,11 +46,11 @@
 
   uptr get(StatType I) const { return atomic_load_relaxed(&StatsArray[I]); }
 
-  LocalStats *Next;
-  LocalStats *Prev;
+  LocalStats *Next = nullptr;
+  LocalStats *Prev = nullptr;
 
 private:
-  atomic_uptr StatsArray[StatCount];
+  atomic_uptr StatsArray[StatCount] = {};
 };
 
 // Global stats, used for aggregation and querying.
diff --git a/compiler-rt/lib/scudo/standalone/tsd.h b/compiler-rt/lib/scudo/standalone/tsd.h
--- a/compiler-rt/lib/scudo/standalone/tsd.h
+++ b/compiler-rt/lib/scudo/standalone/tsd.h
@@ -26,7 +26,7 @@
 template <class Allocator> struct alignas(SCUDO_CACHE_LINE_SIZE) TSD {
   typename Allocator::CacheT Cache;
   typename Allocator::QuarantineCacheT QuarantineCache;
-  u8 DestructorIterations;
+  u8 DestructorIterations = 0;
 
   void initLinkerInitialized(Allocator *Instance) {
     Instance->initCache(&Cache);
@@ -59,7 +59,7 @@
 
 private:
   HybridMutex Mutex;
-  atomic_uptr Precedence;
+  atomic_uptr Precedence = {};
 };
 
 } // namespace scudo
diff --git a/compiler-rt/lib/scudo/standalone/tsd_exclusive.h b/compiler-rt/lib/scudo/standalone/tsd_exclusive.h
--- a/compiler-rt/lib/scudo/standalone/tsd_exclusive.h
+++ b/compiler-rt/lib/scudo/standalone/tsd_exclusive.h
@@ -108,9 +108,9 @@
     Instance->callPostInitCallback();
   }
 
-  pthread_key_t PThreadKey;
-  bool Initialized;
-  atomic_u8 Disabled;
+  pthread_key_t PThreadKey = {};
+  bool Initialized = false;
+  atomic_u8 Disabled = {};
   TSD<Allocator> FallbackTSD;
   HybridMutex Mutex;
   static thread_local ThreadState State;
diff --git a/compiler-rt/lib/scudo/standalone/wrappers_c.cpp b/compiler-rt/lib/scudo/standalone/wrappers_c.cpp
--- a/compiler-rt/lib/scudo/standalone/wrappers_c.cpp
+++ b/compiler-rt/lib/scudo/standalone/wrappers_c.cpp
@@ -26,6 +26,7 @@
 // Export the static allocator so that the C++ wrappers can access it.
 // Technically we could have a completely separated heap for C & C++ but in
 // reality the amount of cross pollination between the two is staggering.
+SCUDO_REQUIRE_CONSTANT_INITIALIZATION
 scudo::Allocator<scudo::Config, SCUDO_PREFIX(malloc_postinit)> SCUDO_ALLOCATOR;
 
 #include "wrappers_c.inc"
diff --git a/compiler-rt/lib/scudo/standalone/wrappers_c_bionic.cpp b/compiler-rt/lib/scudo/standalone/wrappers_c_bionic.cpp
--- a/compiler-rt/lib/scudo/standalone/wrappers_c_bionic.cpp
+++ b/compiler-rt/lib/scudo/standalone/wrappers_c_bionic.cpp
@@ -23,6 +23,7 @@
 #define SCUDO_ALLOCATOR Allocator
 
 extern "C" void SCUDO_PREFIX(malloc_postinit)();
+SCUDO_REQUIRE_CONSTANT_INITIALIZATION
 static scudo::Allocator<scudo::AndroidConfig, SCUDO_PREFIX(malloc_postinit)>
     SCUDO_ALLOCATOR;
 
@@ -36,6 +37,7 @@
 #define SCUDO_ALLOCATOR SvelteAllocator
 
 extern "C" void SCUDO_PREFIX(malloc_postinit)();
+SCUDO_REQUIRE_CONSTANT_INITIALIZATION
 static scudo::Allocator<scudo::AndroidSvelteConfig,
                         SCUDO_PREFIX(malloc_postinit)>
     SCUDO_ALLOCATOR;