diff --git a/compiler-rt/lib/asan/asan_allocator.h b/compiler-rt/lib/asan/asan_allocator.h
--- a/compiler-rt/lib/asan/asan_allocator.h
+++ b/compiler-rt/lib/asan/asan_allocator.h
@@ -118,12 +118,9 @@
 };
 
 #if SANITIZER_CAN_USE_ALLOCATOR64
-# if SANITIZER_FUCHSIA
-const uptr kAllocatorSpace = ~(uptr)0;
-const uptr kAllocatorSize  =  0x40000000000ULL;  // 4T.
-typedef DefaultSizeClassMap SizeClassMap;
-# elif defined(__powerpc64__)
+# if defined(__powerpc64__)
 const uptr kAllocatorSpace = ~(uptr)0;
+// NOTE: This differs slightly from the LSan allocator size which is 4T.
 const uptr kAllocatorSize  =  0x20000000000ULL;  // 2T.
 typedef DefaultSizeClassMap SizeClassMap;
 # elif defined(__aarch64__) && SANITIZER_ANDROID
@@ -150,9 +147,10 @@
 const uptr kAllocatorSize  =  0x8000000000ULL;  // 500G
 typedef DefaultSizeClassMap SizeClassMap;
 # else
-const uptr kAllocatorSpace = 0x600000000000ULL;
-const uptr kAllocatorSize  =  0x40000000000ULL;  // 4T.
-typedef DefaultSizeClassMap SizeClassMap;
+// Use LSan's allocator configs.
+static const uptr kSpaceBeg = __lsan::kAllocatorSpace;
+static const uptr kSpaceSize = __lsan::kAllocatorSize;
+typedef __lsan::SizeClassMap SizeClassMap;
 # endif
 template <typename AddressSpaceViewTy>
 struct AP64 {  // Allocator64 parameters. Deliberately using a short name.