[libfuzzer][MSVC] Make calls to builtin functions work with MSVC

Summary:
Replace calls to builtin functions with macros or functions that call the
Windows-equivalents when targeting windows and call the original
builtin functions everywhere else.
This change makes more parts of libFuzzer buildable with MSVC.

Reviewers: vitalybuka

Reviewed By: vitalybuka

Subscribers: mgorny, rnk, thakis

Differential Revision: https://reviews.llvm.org/D56439

llvm-svn: 350766

1 files changed, 36 insertions, 0 deletions

diff --git a/compiler-rt/lib/fuzzer/FuzzerBuiltins.h b/compiler-rt/lib/fuzzer/FuzzerBuiltins.h
new file mode 100644
index 00000000000..a80938d9a54
--- /dev/null
+++ b/compiler-rt/lib/fuzzer/FuzzerBuiltins.h
@@ -0,0 +1,36 @@
+//===- FuzzerBuiltins.h - Internal header for builtins ----------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Wrapper functions and marcos around builtin functions.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_BUILTINS_H
+#define LLVM_FUZZER_BUILTINS_H
+
+#include "FuzzerDefs.h"
+
+#if !LIBFUZZER_MSVC
+#include <cstdint>
+
+#define GET_CALLER_PC() __builtin_return_address(0)
+
+namespace fuzzer {
+
+inline uint8_t  Bswap(uint8_t x)  { return x; }
+inline uint16_t Bswap(uint16_t x) { return __builtin_bswap16(x); }
+inline uint32_t Bswap(uint32_t x) { return __builtin_bswap32(x); }
+inline uint64_t Bswap(uint64_t x) { return __builtin_bswap64(x); }
+
+inline uint32_t Clzll(unsigned long long X) { return __builtin_clzll(X); }
+inline uint32_t Clz(unsigned long long X) { return __builtin_clz(X); }
+inline int Popcountll(unsigned long long X) { return __builtin_popcountll(X); }
+
+}  // namespace fuzzer
+
+#endif  // !LIBFUZZER_MSVC
+#endif  // LLVM_FUZZER_BUILTINS_H