Index: compiler-rt/lib/sanitizer_common/sanitizer_allocator_internal.h
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_allocator_internal.h
+++ compiler-rt/lib/sanitizer_common/sanitizer_allocator_internal.h
@@ -39,7 +39,9 @@
   using AddressSpaceView = LocalAddressSpaceView;
   using ByteMap = __sanitizer::ByteMap;
   typedef NoOpMapUnmapCallback MapUnmapCallback;
-  static const uptr kFlags = 0;
+  static const uptr kFlags =
+    SANITIZER_SIGN_EXTENDED_ADDRESSES ?
+    SizeClassAllocator32FlagMasks::kSignExtendedAddresses : 0;
 };
 typedef SizeClassAllocator32<AP32> PrimaryInternalAllocator;
 
Index: compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
+++ compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
@@ -41,6 +41,7 @@
   enum {
     kRandomShuffleChunks = 1,
     kUseSeparateSizeClassForBatch = 2,
+    kSignExtendedAddresses = 4,
   };
 };
 
@@ -64,6 +65,9 @@
       SizeClassAllocator32FlagMasks::kRandomShuffleChunks;
   static const bool kUseSeparateSizeClassForBatch = Params::kFlags &
       SizeClassAllocator32FlagMasks::kUseSeparateSizeClassForBatch;
+  static const bool kSignExtendedAddresses = Params::kFlags &
+      SizeClassAllocator32FlagMasks::kSignExtendedAddresses;
+  COMPILER_CHECK(!(kSignExtendedAddresses && (kSpaceSize & (kSpaceSize - 1))));
 
   struct TransferBatch {
     static const uptr kMaxNumCached = SizeClassMap::kMaxNumCachedHint - 2;
@@ -181,6 +185,8 @@
 
   bool PointerIsMine(const void *p) {
     uptr mem = reinterpret_cast<uptr>(p);
+    if (kSignExtendedAddresses)
+      mem &= (kSpaceSize - 1);
     if (mem < kSpaceBeg || mem >= kSpaceBeg + kSpaceSize)
       return false;
     return GetSizeClass(p) != 0;
@@ -273,6 +279,8 @@
   COMPILER_CHECK(sizeof(SizeClassInfo) % kCacheLineSize == 0);
 
   uptr ComputeRegionId(uptr mem) {
+    if (kSignExtendedAddresses)
+      mem &= (kSpaceSize - 1);
     const uptr res = mem >> kRegionSizeLog;
     CHECK_LT(res, kNumPossibleRegions);
     return res;
Index: compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
+++ compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
@@ -1054,6 +1054,8 @@
   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
 # elif defined(__s390x__)
   return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
+# elif defined(__sparc__)
+  return ~(uptr)0;
 # else
   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
 # endif
Index: compiler-rt/lib/sanitizer_common/sanitizer_platform.h
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_platform.h
+++ compiler-rt/lib/sanitizer_common/sanitizer_platform.h
@@ -240,10 +240,21 @@
 # else
 #  define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 48)
 # endif
+#elif defined(__sparc__)
+# define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 52)
 #else
 # define SANITIZER_MMAP_RANGE_SIZE FIRST_32_SECOND_64(1ULL << 32, 1ULL << 47)
 #endif
 
+// Whether the addresses are sign-extended from the VMA range to the word.
+// The SPARC64 Linux port implements this to split the VMA space into two
+// non-contiguous halves with a huge hole in the middle.
+#if defined(__sparc__) && SANITIZER_WORDSIZE == 64
+# define SANITIZER_SIGN_EXTENDED_ADDRESSES 1
+#else
+# define SANITIZER_SIGN_EXTENDED_ADDRESSES 0
+#endif
+
 // The AArch64 linux port uses the canonical syscall set as mandated by
 // the upstream linux community for all new ports. Other ports may still
 // use legacy syscalls.