3 files changed, 71 insertions, 38 deletions

diff --git a/lib/Fuzzer/CMakeLists.txt b/lib/Fuzzer/CMakeLists.txt
index 59cef04cdece..b886021aee3f 100644
--- a/lib/Fuzzer/CMakeLists.txt
+++ b/lib/Fuzzer/CMakeLists.txt
@@ -1,6 +1,18 @@
-set(LIBFUZZER_FLAGS_BASE "${CMAKE_CXX_FLAGS}")
-# Disable the coverage and sanitizer instrumentation for the fuzzer itself.
-set(CMAKE_CXX_FLAGS "${LIBFUZZER_FLAGS_BASE} -fno-sanitize-coverage=trace-pc-guard,edge,trace-cmp,indirect-calls,8bit-counters -Werror")
+include(CheckCXXSourceCompiles)
+
+if( APPLE )
+  CHECK_CXX_SOURCE_COMPILES("
+      static thread_local int blah;
+      int main() {
+        return 0;
+      }
+      " HAS_THREAD_LOCAL)
+
+  if( NOT HAS_THREAD_LOCAL )
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Dthread_local=__thread")
+  endif()
+endif()
+
 if( LLVM_USE_SANITIZE_COVERAGE )
   if(NOT "${LLVM_USE_SANITIZER}" STREQUAL "Address")
     message(FATAL_ERROR
@@ -8,41 +20,50 @@ if( LLVM_USE_SANITIZE_COVERAGE )
       "LLVM_USE_SANITIZE_COVERAGE=YES to be set."
       )
   endif()
+  set(LIBFUZZER_FLAGS_BASE "${CMAKE_CXX_FLAGS}")
+
+  # Disable the coverage and sanitizer instrumentation for the fuzzer itself.
+  set(CMAKE_CXX_FLAGS "${LIBFUZZER_FLAGS_BASE} -fno-sanitize-coverage=trace-pc-guard,edge,trace-cmp,indirect-calls,8bit-counters -Werror")
+endif()
+
+# Compile libFuzzer if the compilation is specifically requested, OR
+# if the platform is known to be working.
+if ( LLVM_USE_SANITIZE_COVERAGE OR CMAKE_SYSTEM_NAME MATCHES "Darwin|Linux" )
   add_library(LLVMFuzzerNoMainObjects OBJECT
-    FuzzerCrossOver.cpp
-    FuzzerDriver.cpp
-    FuzzerExtFunctionsDlsym.cpp
-    FuzzerExtFunctionsDlsymWin.cpp
-    FuzzerExtFunctionsWeak.cpp
-    FuzzerExtraCounters.cpp
-    FuzzerIO.cpp
-    FuzzerIOPosix.cpp
-    FuzzerIOWindows.cpp
-    FuzzerLoop.cpp
-    FuzzerMerge.cpp
-    FuzzerMutate.cpp
-    FuzzerSHA1.cpp
-    FuzzerShmemPosix.cpp
-    FuzzerShmemWindows.cpp
-    FuzzerTracePC.cpp
-    FuzzerTraceState.cpp
-    FuzzerUtil.cpp
-    FuzzerUtilDarwin.cpp
-    FuzzerUtilLinux.cpp
-    FuzzerUtilPosix.cpp
-    FuzzerUtilWindows.cpp
-    )
+      FuzzerCrossOver.cpp
+      FuzzerDriver.cpp
+      FuzzerExtFunctionsDlsym.cpp
+      FuzzerExtFunctionsDlsymWin.cpp
+      FuzzerExtFunctionsWeak.cpp
+      FuzzerExtraCounters.cpp
+      FuzzerIO.cpp
+      FuzzerIOPosix.cpp
+      FuzzerIOWindows.cpp
+      FuzzerLoop.cpp
+      FuzzerMerge.cpp
+      FuzzerMutate.cpp
+      FuzzerSHA1.cpp
+      FuzzerShmemPosix.cpp
+      FuzzerShmemWindows.cpp
+      FuzzerTracePC.cpp
+      FuzzerTraceState.cpp
+      FuzzerUtil.cpp
+      FuzzerUtilDarwin.cpp
+      FuzzerUtilLinux.cpp
+      FuzzerUtilPosix.cpp
+      FuzzerUtilWindows.cpp
+      )
   add_library(LLVMFuzzerNoMain STATIC
-    $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
-    )
+      $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
+      )
   target_link_libraries(LLVMFuzzerNoMain ${LLVM_PTHREAD_LIB})
   add_library(LLVMFuzzer STATIC
-    FuzzerMain.cpp
-    $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
-    )
+      FuzzerMain.cpp
+      $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
+      )
   target_link_libraries(LLVMFuzzer ${LLVM_PTHREAD_LIB})
+endif()
 
-  if( LLVM_INCLUDE_TESTS )
-    add_subdirectory(test)
-  endif()
+if( LLVM_USE_SANITIZE_COVERAGE AND LLVM_INCLUDE_TESTS )
+  add_subdirectory(test)
 endif()
diff --git a/lib/Fuzzer/FuzzerDefs.h b/lib/Fuzzer/FuzzerDefs.h
index bd1827508002..27f5719236dd 100644
--- a/lib/Fuzzer/FuzzerDefs.h
+++ b/lib/Fuzzer/FuzzerDefs.h
@@ -36,17 +36,29 @@
 #error "Support for your platform has not been implemented"
 #endif
 
+#ifndef __has_attribute
+#  define __has_attribute(x) 0
+#endif
+
 #define LIBFUZZER_POSIX LIBFUZZER_APPLE || LIBFUZZER_LINUX
 
 #ifdef __x86_64
-#define ATTRIBUTE_TARGET_POPCNT __attribute__((target("popcnt")))
+#  if __has_attribute(target)
+#    define ATTRIBUTE_TARGET_POPCNT __attribute__((target("popcnt")))
+#  else
+#    define ATTRIBUTE_TARGET_POPCNT
+#  endif
 #else
-#define ATTRIBUTE_TARGET_POPCNT
+#  define ATTRIBUTE_TARGET_POPCNT
 #endif
 
 
 #ifdef __clang__  // avoid gcc warning.
-#  define ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize("memory")))
+#  if __has_attribute(no_sanitize)
+#    define ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize("memory")))
+#  else
+#    define ATTRIBUTE_NO_SANITIZE_MEMORY
+#  endif
 #  define ALWAYS_INLINE __attribute__((always_inline))
 #else
 #  define ATTRIBUTE_NO_SANITIZE_MEMORY
diff --git a/lib/Fuzzer/FuzzerMerge.h b/lib/Fuzzer/FuzzerMerge.h
index cf4a0863571d..dd4c37b6e39c 100644
--- a/lib/Fuzzer/FuzzerMerge.h
+++ b/lib/Fuzzer/FuzzerMerge.h
@@ -69,7 +69,7 @@ struct Merger {
   size_t Merge(const std::set<uint32_t> &InitialFeatures,
                std::vector<std::string> *NewFiles);
   size_t Merge(std::vector<std::string> *NewFiles) {
-    return Merge({}, NewFiles);
+    return Merge(std::set<uint32_t>{}, NewFiles);
   }
   size_t ApproximateMemoryConsumption() const;
   std::set<uint32_t> AllFeatures() const;