diff --git a/compiler-rt/lib/asan/asan_mapping.h b/compiler-rt/lib/asan/asan_mapping.h
--- a/compiler-rt/lib/asan/asan_mapping.h
+++ b/compiler-rt/lib/asan/asan_mapping.h
@@ -13,8 +13,6 @@
 #ifndef ASAN_MAPPING_H
 #define ASAN_MAPPING_H
 
-#include "asan_internal.h"
-
 // The full explanation of the memory mapping could be found here:
 // https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm
 //
@@ -153,8 +151,6 @@
 
 #define ASAN_SHADOW_SCALE 3
 
-static const u64 kDefaultShadowSentinel = ~(uptr)0;
-
 #if SANITIZER_FUCHSIA
 #  define ASAN_SHADOW_OFFSET_CONST (0)
 #elif SANITIZER_WORDSIZE == 32
@@ -199,35 +195,43 @@
 #  elif SANITIZER_WINDOWS64
 #    define ASAN_SHADOW_OFFSET_DYNAMIC
 #  else
-#    define ASAN_SHADOW_OFFSET_CONST \
-      0x000000007FFFFFFF & (~0xFFFULL << ASAN_SHADOW_SCALE)
+#    if ASAN_SHADOW_SCALE != 3
+#      error "Value below is based on shadow scale = 3."
+#      error "Original formula was: 0x7FFFFFFF & (~0xFFFULL << SHADOW_SCALE)."
+#    endif
+#    define ASAN_SHADOW_OFFSET_CONST 0x000000007fff8000
 #  endif
 #endif
 
-#if defined(ASAN_SHADOW_OFFSET_CONST)
+#if defined(__cplusplus)
+#  include "asan_internal.h"
+
+static const u64 kDefaultShadowSentinel = ~(uptr)0;
+
+#  if defined(ASAN_SHADOW_OFFSET_CONST)
 static const u64 kConstShadowOffset = ASAN_SHADOW_OFFSET_CONST;
-#  define ASAN_SHADOW_OFFSET kConstShadowOffset
-#elif defined(ASAN_SHADOW_OFFSET_DYNAMIC)
-#  define ASAN_SHADOW_OFFSET __asan_shadow_memory_dynamic_address
-#else
-#  error "ASAN_SHADOW_OFFSET can't be determined."
-#endif
+#    define ASAN_SHADOW_OFFSET kConstShadowOffset
+#  elif defined(ASAN_SHADOW_OFFSET_DYNAMIC)
+#    define ASAN_SHADOW_OFFSET __asan_shadow_memory_dynamic_address
+#  else
+#    error "ASAN_SHADOW_OFFSET can't be determined."
+#  endif
 
-#if SANITIZER_ANDROID && defined(__arm__)
-# define ASAN_PREMAP_SHADOW 1
-#else
-# define ASAN_PREMAP_SHADOW 0
-#endif
+#  if SANITIZER_ANDROID && defined(__arm__)
+#    define ASAN_PREMAP_SHADOW 1
+#  else
+#    define ASAN_PREMAP_SHADOW 0
+#  endif
 
-#define ASAN_SHADOW_GRANULARITY (1ULL << ASAN_SHADOW_SCALE)
+#  define ASAN_SHADOW_GRANULARITY (1ULL << ASAN_SHADOW_SCALE)
 
-#define DO_ASAN_MAPPING_PROFILE 0  // Set to 1 to profile the functions below.
+#  define DO_ASAN_MAPPING_PROFILE 0  // Set to 1 to profile the functions below.
 
-#if DO_ASAN_MAPPING_PROFILE
-# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
-#else
-# define PROFILE_ASAN_MAPPING()
-#endif
+#  if DO_ASAN_MAPPING_PROFILE
+#    define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
+#  else
+#    define PROFILE_ASAN_MAPPING()
+#  endif
 
 // If 1, all shadow boundaries are constants.
 // Don't set to 1 other than for testing.
@@ -382,4 +386,6 @@
 
 }  // namespace __asan
 
+#endif  // __cplusplus
+
 #endif  // ASAN_MAPPING_H