Index: compiler-rt/trunk/cmake/config-ix.cmake
===================================================================
--- compiler-rt/trunk/cmake/config-ix.cmake
+++ compiler-rt/trunk/cmake/config-ix.cmake
@@ -429,15 +429,13 @@
   set(COMPILER_RT_HAS_SANITIZER_COMMON FALSE)
 endif()
 
-if (COMPILER_RT_HAS_SANITIZER_COMMON AND
-    (NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 4))
+if (COMPILER_RT_HAS_SANITIZER_COMMON)
   set(COMPILER_RT_HAS_INTERCEPTION TRUE)
 else()
   set(COMPILER_RT_HAS_INTERCEPTION FALSE)
 endif()
 
-if (COMPILER_RT_HAS_SANITIZER_COMMON AND ASAN_SUPPORTED_ARCH AND
-    (NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 4))
+if (COMPILER_RT_HAS_SANITIZER_COMMON AND ASAN_SUPPORTED_ARCH)
   set(COMPILER_RT_HAS_ASAN TRUE)
 else()
   set(COMPILER_RT_HAS_ASAN FALSE)
Index: compiler-rt/trunk/lib/asan/asan_win.cc
===================================================================
--- compiler-rt/trunk/lib/asan/asan_win.cc
+++ compiler-rt/trunk/lib/asan/asan_win.cc
@@ -46,11 +46,20 @@
 const char* __asan_default_default_options() { return ""; }
 const char* __asan_default_default_suppressions() { return ""; }
 void __asan_default_on_error() {}
+// 64-bit msvc will not prepend an underscore for symbols.
+#ifdef _WIN64
+#pragma comment(linker, "/alternatename:__sanitizer_malloc_hook=__sanitizer_default_malloc_hook")  // NOLINT
+#pragma comment(linker, "/alternatename:__sanitizer_free_hook=__sanitizer_default_free_hook")      // NOLINT
+#pragma comment(linker, "/alternatename:__asan_default_options=__asan_default_default_options")    // NOLINT
+#pragma comment(linker, "/alternatename:__asan_default_suppressions=__asan_default_default_suppressions")    // NOLINT
+#pragma comment(linker, "/alternatename:__asan_on_error=__asan_default_on_error")                  // NOLINT
+#else
 #pragma comment(linker, "/alternatename:___sanitizer_malloc_hook=___sanitizer_default_malloc_hook")  // NOLINT
 #pragma comment(linker, "/alternatename:___sanitizer_free_hook=___sanitizer_default_free_hook")      // NOLINT
 #pragma comment(linker, "/alternatename:___asan_default_options=___asan_default_default_options")    // NOLINT
 #pragma comment(linker, "/alternatename:___asan_default_suppressions=___asan_default_default_suppressions")    // NOLINT
 #pragma comment(linker, "/alternatename:___asan_on_error=___asan_default_on_error")                  // NOLINT
+#endif
 // }}}
 }  // extern "C"
 
@@ -61,6 +70,9 @@
   REAL(RaiseException)(a, b, c, d);
 }
 
+// TODO(wwchrome): Win64 has no _except_handler3/4.
+// Need to implement _C_specific_handler instead.
+#ifndef _WIN64
 INTERCEPTOR(int, _except_handler3, void *a, void *b, void *c, void *d) {
   CHECK(REAL(_except_handler3));
   __asan_handle_no_return();
@@ -76,6 +88,7 @@
   __asan_handle_no_return();
   return REAL(_except_handler4)(a, b, c, d);
 }
+#endif
 
 static thread_return_t THREAD_CALLING_CONV asan_thread_start(void *arg) {
   AsanThread *t = (AsanThread*)arg;
@@ -139,8 +152,12 @@
 void InitializePlatformInterceptors() {
   ASAN_INTERCEPT_FUNC(CreateThread);
   ASAN_INTERCEPT_FUNC(RaiseException);
+
+// TODO(wwchrome): Win64 uses _C_specific_handler instead.
+#ifndef _WIN64
   ASAN_INTERCEPT_FUNC(_except_handler3);
   ASAN_INTERCEPT_FUNC(_except_handler4);
+#endif
 
   // NtWaitForWorkViaWorkerFactory is always linked dynamically.
   CHECK(::__interception::OverrideFunction(
Index: compiler-rt/trunk/lib/interception/interception_win.cc
===================================================================
--- compiler-rt/trunk/lib/interception/interception_win.cc
+++ compiler-rt/trunk/lib/interception/interception_win.cc
@@ -36,7 +36,7 @@
 }
 
 static void WriteJumpInstruction(char *jmp_from, char *to) {
-  // jmp XXYYZZWW = E9 WW ZZ YY XX, where XXYYZZWW is an offset fromt jmp_from
+  // jmp XXYYZZWW = E9 WW ZZ YY XX, where XXYYZZWW is an offset from jmp_from
   // to the next instruction to the destination.
   ptrdiff_t offset = to - jmp_from - 5;
   *jmp_from = '\xE9';
@@ -68,6 +68,12 @@
 
 // Returns 0 on error.
 static size_t RoundUpToInstrBoundary(size_t size, char *code) {
+#ifdef _WIN64
+  // TODO(wwchrome): Implement similar logic for x64 instructions.
+  // Win64 RoundUpToInstrBoundary is not supported yet.
+  __debugbreak();
+  return 0;
+#else
   size_t cursor = 0;
   while (cursor < size) {
     switch (code[cursor]) {
@@ -140,12 +146,16 @@
   }
 
   return cursor;
+#endif
 }
 
 bool OverrideFunction(uptr old_func, uptr new_func, uptr *orig_old_func) {
 #ifdef _WIN64
-#error OverrideFunction is not yet supported on x64
-#endif
+  // TODO(wwchrome): Implement using x64 jmp.
+  // OverrideFunction is not yet supported on x64.
+  __debugbreak();
+  return false;
+#else
   // Function overriding works basically like this:
   // We write "jmp <new_func>" (5 bytes) at the beginning of the 'old_func'
   // to override it.
@@ -190,6 +200,7 @@
     return false;  // not clear if this failure bothers us.
 
   return true;
+#endif
 }
 
 static void **InterestingDLLsAvailable() {
Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_atomic_msvc.h
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_atomic_msvc.h
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_atomic_msvc.h
@@ -171,12 +171,16 @@
   return (u32)_InterlockedExchange((volatile long*)&a->val_dont_use, v);
 }
 
-#ifndef _WIN64
-
 INLINE bool atomic_compare_exchange_strong(volatile atomic_uint8_t *a,
                                            u8 *cmp,
                                            u8 xchgv,
                                            memory_order mo) {
+#ifdef _WIN64
+  // TODO(wwchrome): Implement same functionality without inline asm.
+  // Inline asm not supported in Win64.
+  __debugbreak();
+  return false;
+#else
   (void)mo;
   DCHECK(!((uptr)a % sizeof(*a)));
   u8 cmpv = *cmp;
@@ -192,9 +196,8 @@
     return true;
   *cmp = prev;
   return false;
-}
-
 #endif
+}
 
 INLINE bool atomic_compare_exchange_strong(volatile atomic_uintptr_t *a,
                                            uptr *cmp,
Index: compiler-rt/trunk/test/asan/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/test/asan/CMakeLists.txt
+++ compiler-rt/trunk/test/asan/CMakeLists.txt
@@ -3,6 +3,12 @@
 set(ASAN_TESTSUITES)
 set(ASAN_DYNAMIC_TESTSUITES)
 
+# TODO(wwchrome): Re-enable Win64 asan tests when ready.
+# Disable tests for asan Win64 temporarily.
+if(NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 8)
+  set(EXCLUDE_FROM_ALL TRUE)
+endif()
+
 macro(get_bits_for_arch arch bits)
   if (${arch} MATCHES "i386|i686|arm|mips|mipsel")
     set(${bits} 32)
@@ -102,6 +108,7 @@
 if(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME)
   # Add check-dynamic-asan target. It is a part of check-all only on Windows,
   # where we want to always test both dynamic and static runtime.
+
   if(NOT OS_NAME MATCHES "Windows")
     set(EXCLUDE_FROM_ALL TRUE)
   endif()
@@ -115,3 +122,8 @@
     set(EXCLUDE_FROM_ALL FALSE)
   endif()
 endif()
+
+# TODO(wwchrome): Re-enable the tests for asan Win64 when ready.
+if(NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 8)
+  set(EXCLUDE_FROM_ALL FALSE)
+endif()
Index: compiler-rt/trunk/test/ubsan/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/test/ubsan/CMakeLists.txt
+++ compiler-rt/trunk/test/ubsan/CMakeLists.txt
@@ -32,7 +32,11 @@
   add_ubsan_testsuite("Standalone" ubsan ${arch})
 
   if(COMPILER_RT_HAS_ASAN AND ";${ASAN_SUPPORTED_ARCH};" MATCHES ";${arch};")
-    add_ubsan_testsuite("AddressSanitizer" asan ${arch})
+    # TODO(wwchrome): Re-enable ubsan for asan win 64-bit when ready.
+    # Disable ubsan with AddressSanitizer tests for Windows 64-bit.
+    if(NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 4)
+      add_ubsan_testsuite("AddressSanitizer" asan ${arch})
+    endif()
   endif()
   if(COMPILER_RT_HAS_MSAN AND ";${MSAN_SUPPORTED_ARCH};" MATCHES ";${arch};")
     add_ubsan_testsuite("MemorySanitizer" msan ${arch})