Hide some SyzyASan specific code behind an '#if defined(COMPILER_MSVC)'.

base/debug/asan_invalid_access.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #include "base/debug/alias.h"
 #include "base/debug/asan_invalid_access.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 
 namespace base {
 namespace debug {
 
 namespace {
 
-#if defined(SYZYASAN)
+#if defined(SYZYASAN) && defined(COMPILER_MSVC)
 // Disable warning C4530: "C++ exception handler used, but unwind semantics are
 // not enabled". We don't want to change the compilation flags just for this
 // test, and no exception should be triggered here, so this warning has no value
 // here.
 #pragma warning(push)
 #pragma warning(disable: 4530)
 // Corrupt a memory block and make sure that the corruption gets detected either
 // when we free it or when another crash happens (if |induce_crash| is set to
 // true).
 NOINLINE void CorruptMemoryBlock(bool induce_crash) {
   // NOTE(sebmarchand): We intentionally corrupt a memory block here in order to
   //     trigger an Address Sanitizer (ASAN) error report.
   static const int kArraySize = 5;
   int* array = new int[kArraySize];
   // Encapsulate the invalid memory access into a try-catch statement to prevent
   // this function from being instrumented. This way the underflow won't be
   // detected but the corruption will (as the allocator will still be hooked).
   try {
     // Declares the dummy value as volatile to make sure it doesn't get
     // optimized away.
     int volatile dummy = array[-1]--;
     base::debug::Alias(const_cast<int*>(&dummy));
   } catch (...) {
   }
   if (induce_crash)
     CHECK(false);
   delete[] array;
 }
 #pragma warning(pop)
-#endif
+#endif  // SYZYASAN && COMPILER_MSVC
 
 }  // namespace
 
 #if defined(ADDRESS_SANITIZER) || defined(SYZYASAN)
 // NOTE(sebmarchand): We intentionally perform some invalid heap access here in
 //     order to trigger an AddressSanitizer (ASan) error report.
 
 static const size_t kArraySize = 5;
 
 void AsanHeapOverflow() {
@@ skipping 24 matching lines @@
   // away.
   int volatile dummy = 0;
   int* dangling = array.get();
   array.reset();
   dummy = dangling[kArraySize / 2];
   base::debug::Alias(const_cast<int*>(&dummy));
 }
 
 #endif  // ADDRESS_SANITIZER || SYZYASAN
 
-#if defined(SYZYASAN)
+#if defined(SYZYASAN) && defined(COMPILER_MSVC)
 void AsanCorruptHeapBlock() {
   CorruptMemoryBlock(false);
 }
 
 void AsanCorruptHeap() {
   CorruptMemoryBlock(true);
 }
-#endif  // SYZYASAN
+#endif  // SYZYASAN && COMPILER_MSVC
 
 }  // namespace debug
 }  // namespace base