From 53ff84bf1123f2c211f641f73e22290a13eee669 Mon Sep 17 00:00:00 2001
From: Kostya Serebryany <kcc@google.com>
Date: Tue, 12 Jan 2016 16:50:18 +0000
Subject: [PATCH] [libFuzzer] add a macro
 LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257482 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Fuzzer/FuzzerTraceState.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/Fuzzer/FuzzerTraceState.cpp b/lib/Fuzzer/FuzzerTraceState.cpp
index 00f1ebd0619..b2006fa3aa4 100644
--- a/lib/Fuzzer/FuzzerTraceState.cpp
+++ b/lib/Fuzzer/FuzzerTraceState.cpp
@@ -542,6 +542,12 @@ void dfsan_weak_hook_strcmp(void *caller_pc, const char *s1, const char *s2,
                           reinterpret_cast<const uint8_t *>(s2), L1, L2);
 }
 
+// We may need to avoid defining weak hooks to stay compatible with older clang.
+#ifndef LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
+# define LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS 1
+#endif
+
+#if LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
 void __sanitizer_weak_hook_memcmp(void *caller_pc, const void *s1,
                                   const void *s2, size_t n, int result) {
   if (!TS) return;
@@ -576,6 +582,8 @@ void __sanitizer_weak_hook_strcmp(void *caller_pc, const char *s1,
                           reinterpret_cast<const uint8_t *>(s2));
 }
 
+#endif  // LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
+
 __attribute__((visibility("default")))
 void __sanitizer_cov_trace_cmp(uint64_t SizeAndType, uint64_t Arg1,
                                uint64_t Arg2) {