diff --git a/INSTALL b/INSTALL
index dedf236a8..79a0af7d9 100644
--- a/INSTALL
+++ b/INSTALL
@@ -11,27 +11,9 @@ GRUB depends on some software packages installed into your system. If
you don't have any of them, please obtain and install them before
configuring the GRUB.
-* GCC 4.1.3 or later
- Note: older versions may work but support is limited
-
- Experimental support for clang 3.3 or later (results in much bigger binaries)
+* GCC 5.1.0 or later
+ Experimental support for clang 3.8.0 or later (results in much bigger binaries)
for i386, x86_64, arm (including thumb), arm64, mips(el), powerpc, sparc64
- Note: clang 3.2 or later works for i386 and x86_64 targets but results in
- much bigger binaries.
- earlier versions not tested
- Note: clang 3.2 or later works for arm
- earlier versions not tested
- Note: clang on arm64 is not supported due to
- https://llvm.org/bugs/show_bug.cgi?id=26030
- Note: clang 3.3 or later works for mips(el)
- earlier versions fail to generate .reginfo and hence gprel relocations
- fail.
- Note: clang 3.2 or later works for powerpc
- earlier versions not tested
- Note: clang 3.5 or later works for sparc64
- earlier versions return "error: unable to interface with target machine"
- Note: clang has no support for ia64 and hence you can't compile GRUB
- for ia64 with clang
* GNU Make
* GNU Bison 2.3 or later
* GNU gettext 0.17 or later
diff --git a/include/grub/compiler.h b/include/grub/compiler.h
index c9e1d7a73..8f3be3ae7 100644
--- a/include/grub/compiler.h
+++ b/include/grub/compiler.h
@@ -48,4 +48,12 @@
# define WARN_UNUSED_RESULT
#endif
+#if defined(__clang__) && defined(__clang_major__) && defined(__clang_minor__)
+# define CLANG_PREREQ(maj,min) \
+ ((__clang_major__ > (maj)) || \
+ (__clang_major__ == (maj) && __clang_minor__ >= (min)))
+#else
+# define CLANG_PREREQ(maj,min) 0
+#endif
+
#endif /* ! GRUB_COMPILER_HEADER */
diff --git a/include/grub/safemath.h b/include/grub/safemath.h
new file mode 100644
index 000000000..c17b89bba
--- /dev/null
+++ b/include/grub/safemath.h
@@ -0,0 +1,37 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2020 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see .
+ *
+ * Arithmetic operations that protect against overflow.
+ */
+
+#ifndef GRUB_SAFEMATH_H
+#define GRUB_SAFEMATH_H 1
+
+#include
+
+/* These appear in gcc 5.1 and clang 3.8. */
+#if GNUC_PREREQ(5, 1) || CLANG_PREREQ(3, 8)
+
+#define grub_add(a, b, res) __builtin_add_overflow(a, b, res)
+#define grub_sub(a, b, res) __builtin_sub_overflow(a, b, res)
+#define grub_mul(a, b, res) __builtin_mul_overflow(a, b, res)
+
+#else
+#error gcc 5.1 or newer or clang 3.8 or newer is required
+#endif
+
+#endif /* GRUB_SAFEMATH_H */