diff --git a/cmake/toolchain/xcc/generic.cmake b/cmake/toolchain/xcc/generic.cmake
index fec95ceac889ae..6f519612e07da1 100644
--- a/cmake/toolchain/xcc/generic.cmake
+++ b/cmake/toolchain/xcc/generic.cmake
@@ -29,10 +29,8 @@ set(NOSYSDEF_CFLAG "")
 
 list(APPEND TOOLCHAIN_C_FLAGS -fms-extensions)
 
-# xcc doesn't have this, so we need to define it here.
-# This is the same as in the xcc toolchain spec files.
 list(APPEND TOOLCHAIN_C_FLAGS
-  -D__SIZEOF_LONG__=4
+  -imacros${ZEPHYR_BASE}/include/toolchain/xcc_missing_defs.h
   )
 
 set(TOOLCHAIN_HAS_NEWLIB OFF CACHE BOOL "True if toolchain supports newlib")
diff --git a/include/toolchain/xcc_missing_defs.h b/include/toolchain/xcc_missing_defs.h
new file mode 100644
index 00000000000000..77c97b2230898b
--- /dev/null
+++ b/include/toolchain/xcc_missing_defs.h
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2019 BayLibre SAS
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*
+ * Basic macro definitions that gcc and clang provide on their own
+ * but that xcc lacks. Only those that Zephyr requires are provided here.
+ */
+
+#ifndef ZEPHYR_INCLUDE_TOOLCHAIN_XCC_MISSING_DEFS_H_
+#define ZEPHYR_INCLUDE_TOOLCHAIN_XCC_MISSING_DEFS_H_
+
+#if __CHAR_BIT__ == 8
+#define __SCHAR_WIDTH__ 8
+#else
+#error "unexpected __CHAR_BIT__ value"
+#endif
+
+#if __SHRT_MAX__ == 32767
+#define __SHRT_WIDTH__ 16
+#define __SIZEOF_SHORT__ 2
+#else
+#error "unexpected __SHRT_WIDTH__ value"
+#endif
+
+#if __INT_MAX__ == 2147483647
+#define __INT_WIDTH__ 32
+#define __SIZEOF_INT__ 4
+#else
+#error "unexpected __INT_MAX__ value"
+#endif
+
+#if __LONG_MAX__ == 2147483647L
+#define __LONG_WIDTH__ 32
+#define __SIZEOF_LONG__ 4
+#else
+#error "unexpected __LONG_MAX__ value"
+#endif
+
+#if __LONG_LONG_MAX__ == 9223372036854775807LL
+#define __LONG_LONG_WIDTH__ 64
+#define __SIZEOF_LONG_LONG__ 8
+#else
+#error "unexpected __LONG_LONG_MAX__ value"
+#endif
+
+#if __INTMAX_MAX__ == 9223372036854775807LL
+#define __INTMAX_WIDTH__ 64
+#define __SIZEOF_INTMAX__ 8
+#define __UINTMAX_MAX__ 0xffffffffffffffffULL
+#define __UINTMAX_WIDTH__ 64
+#define __SIZEOF_UINTMAX__ 8
+#else
+#error "unexpected __INTMAX_MAX__ value"
+#endif
+
+/*
+ * No xcc provided definitions related to pointers, so let's just enforce
+ * the Zephyr expected type.
+ */
+
+#define __INTPTR_MAX__ 0x7fffffffL
+#define __INTPTR_TYPE__ long int
+#define __INTPTR_WIDTH__ 32
+#define __SIZEOF_POINTER__ 4
+
+#define __PTRDIFF_MAX__ 0x7fffffffL
+#define __PTRDIFF_WIDTH__ 32
+#define __SIZEOF_PTRDIFF_T__ 4
+
+#define __UINTPTR_MAX__ 0xffffffffLU
+#define __UINTPTR_TYPE__ long unsigned int
+
+/*
+ * xcc already defines __SIZE_TYPE__ as "unsigned int" but there is no way
+ * to safeguard that here with preprocessor equality.
+ */
+
+#define __SIZE_MAX__ 0xffffffffU
+#define __SIZE_WIDTH__ 32
+#define __SIZEOF_SIZE_T__ 4
+
+/*
+ * The following defines are inferred from the xcc provided defines
+ * already tested above.
+ */
+
+#define __INT8_MAX__ 0x7f
+#define __INT8_TYPE__ signed char
+
+#define __INT16_MAX__ 0x7fff
+#define __INT16_TYPE__ short int
+
+#define __INT32_MAX__ 0x7fffffff
+#define __INT32_TYPE__ int
+
+#define __INT64_MAX__ 0x7fffffffffffffffLL
+#define __INT64_TYPE__ long long int
+
+#define __INT_FAST8_MAX__ 0x7f
+#define __INT_FAST8_TYPE__ signed char
+#define __INT_FAST8_WIDTH__ 8
+
+#define __INT_FAST16_MAX__ 0x7fffffff
+#define __INT_FAST16_TYPE__ int
+#define __INT_FAST16_WIDTH__ 32
+
+#define __INT_FAST32_MAX__ 0x7fffffff
+#define __INT_FAST32_TYPE__ int
+#define __INT_FAST32_WIDTH__ 32
+
+#define __INT_FAST64_MAX__ 0x7fffffffffffffffLL
+#define __INT_FAST64_TYPE__ long long int
+#define __INT_FAST64_WIDTH__ 64
+
+#define __INT_LEAST8_MAX__ 0x7f
+#define __INT_LEAST8_TYPE__ signed char
+#define __INT_LEAST8_WIDTH__ 8
+
+#define __INT_LEAST16_MAX__ 0x7fff
+#define __INT_LEAST16_TYPE__ short int
+#define __INT_LEAST16_WIDTH__ 16
+
+#define __INT_LEAST32_MAX__ 0x7fffffff
+#define __INT_LEAST32_TYPE__ int
+#define __INT_LEAST32_WIDTH__ 32
+
+#define __INT_LEAST64_MAX__ 0x7fffffffffffffffLL
+#define __INT_LEAST64_TYPE__ long long int
+#define __INT_LEAST64_WIDTH__ 64
+
+#define __UINT8_MAX__ 0xff
+#define __UINT8_TYPE__ unsigned char
+
+#define __UINT16_MAX__ 0xffff
+#define __UINT16_TYPE__ short unsigned int
+
+#define __UINT32_MAX__ 0xffffffffU
+#define __UINT32_TYPE__ unsigned int
+
+#define __UINT64_MAX__ 0xffffffffffffffffULL
+#define __UINT64_TYPE__ long long unsigned int
+
+#define __UINT_FAST8_MAX__ 0xff
+#define __UINT_FAST8_TYPE__ unsigned char
+
+#define __UINT_FAST16_MAX__ 0xffffffffU
+#define __UINT_FAST16_TYPE__ unsigned int
+
+#define __UINT_FAST32_MAX__ 0xffffffffU
+#define __UINT_FAST32_TYPE__ unsigned int
+
+#define __UINT_FAST64_MAX__ 0xffffffffffffffffULL
+#define __UINT_FAST64_TYPE__ long long unsigned int
+
+#define __UINT_LEAST8_MAX__ 0xff
+#define __UINT_LEAST8_TYPE__ unsigned char
+
+#define __UINT_LEAST16_MAX__ 0xffff
+#define __UINT_LEAST16_TYPE__ short unsigned int
+
+#define __UINT_LEAST32_MAX__ 0xffffffffU
+#define __UINT_LEAST32_TYPE__ unsigned int
+
+#define __UINT_LEAST64_MAX__ 0xffffffffffffffffULL
+#define __UINT_LEAST64_TYPE__ long long unsigned int
+
+#endif