1 files changed, 18 insertions, 10 deletions
diff --git a/lib/fuzzer/FuzzerInterface.h b/lib/fuzzer/FuzzerInterface.h
index 0f7effb2ab6a..4f62822eac05 100644
--- a/lib/fuzzer/FuzzerInterface.h
+++ b/lib/fuzzer/FuzzerInterface.h
@@ -1,9 +1,8 @@
 //===- FuzzerInterface.h - Interface header for the Fuzzer ------*- C++ -* ===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 // Define the interface between libFuzzer and the library being tested.
@@ -26,25 +25,32 @@
 extern "C" {
 #endif  // __cplusplus
 
+// Define FUZZER_INTERFACE_VISIBILITY to set default visibility in a way that
+// doesn't break MSVC.
+#if defined(_WIN32)
+#define FUZZER_INTERFACE_VISIBILITY __declspec(dllexport)
+#else
+#define FUZZER_INTERFACE_VISIBILITY __attribute__((visibility("default")))
+#endif
+
 // Mandatory user-provided target function.
 // Executes the code under test with [Data, Data+Size) as the input.
 // libFuzzer will invoke this function *many* times with different inputs.
 // Must return 0.
-__attribute__((visibility("default"))) int
+FUZZER_INTERFACE_VISIBILITY int
 LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size);
 
 // Optional user-provided initialization function.
 // If provided, this function will be called by libFuzzer once at startup.
 // It may read and modify argc/argv.
 // Must return 0.
-__attribute__((visibility("default"))) int LLVMFuzzerInitialize(int *argc,
-                                                                char ***argv);
+FUZZER_INTERFACE_VISIBILITY int LLVMFuzzerInitialize(int *argc, char ***argv);
 
 // Optional user-provided custom mutator.
 // Mutates raw data in [Data, Data+Size) inplace.
 // Returns the new size, which is not greater than MaxSize.
 // Given the same Seed produces the same mutation.
-__attribute__((visibility("default"))) size_t
+FUZZER_INTERFACE_VISIBILITY size_t
 LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size, size_t MaxSize,
                         unsigned int Seed);
 
@@ -52,7 +58,7 @@ LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size, size_t MaxSize,
 // Combines pieces of Data1 & Data2 together into Out.
 // Returns the new size, which is not greater than MaxOutSize.
 // Should produce the same mutation given the same Seed.
-__attribute__((visibility("default"))) size_t
+FUZZER_INTERFACE_VISIBILITY size_t
 LLVMFuzzerCustomCrossOver(const uint8_t *Data1, size_t Size1,
                           const uint8_t *Data2, size_t Size2, uint8_t *Out,
                           size_t MaxOutSize, unsigned int Seed);
@@ -61,9 +67,11 @@ LLVMFuzzerCustomCrossOver(const uint8_t *Data1, size_t Size1,
 // libFuzzer-provided function to be used inside LLVMFuzzerCustomMutator.
 // Mutates raw data in [Data, Data+Size) inplace.
 // Returns the new size, which is not greater than MaxSize.
-__attribute__((visibility("default"))) size_t
+FUZZER_INTERFACE_VISIBILITY size_t
 LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize);
 
+#undef FUZZER_INTERFACE_VISIBILITY
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif  // __cplusplus