Improved the CMakeLists.txt just slightly. Provided a default, weak-attributed main function into libdeepstate so that tests don't need to define them. The weak attribute means that any main function defined by libfuzzer will be a strong symbol and take over, so there won't be a conflict. Adjusted examples accordingly to omit now redundant conditionally-compiled main functions, as that leaked out too many underlying details.

CMakeLists.txt

@@ -15,15 +15,31 @@
 project(deepstate)
 cmake_minimum_required(VERSION 2.8)
 
+if (NOT DEFINED BUILD_LIBFUZZER AND DEFINED $ENV{BUILD_LIBFUZZER})
+  set(BUILD_LIBFUZZER "$ENV{BUILD_LIBFUZZER}")
+endif()
+
+if (BUILD_LIBFUZZER)
+  if(NOT DEFINED CMAKE_C_COMPILER)
+    set(CMAKE_C_COMPILER clang)
+  endif()
+
+  if(NOT DEFINED CMAKE_CXX_COMPILER)
+    set(CMAKE_CXX_COMPILER clang++)
+  endif()
+
+  if (NOT "${CMAKE_C_COMPILER_ID}" STREQUAL "Clang" AND NOT "${CMAKE_C_COMPILER_ID}" STREQUAL "AppleClang")
+    message(FATAL_ERROR "DeepState's libFuzzer mode requires the Clang C compiler.")
+  endif()
+
+  if (NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
+    message(FATAL_ERROR "DeepState's libFuzzer mode requires the Clang C++ compiler.")
+  endif()
+endif()
+
 enable_language(C)
 enable_language(CXX)
 
-set(BUILD_LIBFUZZER "$ENV{BUILD_LIBFUZZER}")
-if (BUILD_LIBFUZZER)
-    SET(CMAKE_C_COMPILER clang)
-    SET(CMAKE_CXX_COMPILER clang++)
-endif()
-
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 if(NOT CMAKE_BUILD_TYPE)

examples/Crash.cpp

@@ -35,10 +35,3 @@ TEST(Crash, SegFault) {
 
   ASSERT_EQ(x, x);
 }
-
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

examples/Euler.cpp

@@ -39,9 +39,3 @@ TEST(Euler, SumsOfLikePowers) {
       << "^5 + " << d << "^5 = " << e << "^5";
 }
 
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

examples/Fixture.cpp

@@ -35,10 +35,3 @@ class MyTest : public deepstate::Test {
 TEST_F(MyTest, Something) {
   ASSUME_NE(x, 0);
 }
-
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

examples/IntegerArithmetic.cpp

@@ -44,10 +44,3 @@ TEST(Arithmetic, InvertibleMultiplication_CanFail) {
         << x << " != (" << x << " / " << y << ") * " << y;
   });
 }
-
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

examples/IntegerOverflow.cpp

@@ -15,7 +15,7 @@
  */
 
 #include <deepstate/DeepState.hpp>
-
+#include <climits>
 using namespace deepstate;
 
 DEEPSTATE_NOINLINE int ident1(int x) {
@@ -40,9 +40,3 @@ TEST(SignedInteger, MultiplicationOverflow) {
       << x << " squared overflowed.";
 }
 
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

examples/Lists.cpp

@@ -30,10 +30,3 @@ TEST(Vector, DoubleReversal) {
         << "Double reverse of vectors must be equal.";
   });
 }
-
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  DeepState_Run();
-}
-#endif

examples/OneOf.cpp

@@ -63,10 +63,3 @@ TEST(OneOfExample, ProduceSixtyOrHigher) {
       << x << " is >= 60: " << " did " << choices << " from " << start;
   }
 }
-
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

examples/Primes.cpp

@@ -52,10 +52,3 @@ TEST(PrimePolynomial, OnlyGeneratesPrimes_NoStreaming) {
   DeepState_Assert(poly != (y * z));
   DeepState_Assert(IsPrime(Pump(poly)));
 }
-
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

examples/StreamingAndFormatting.cpp

@@ -40,9 +40,3 @@ TEST(Formatting, OverridePrintf) {
   printf("hello again!");
 }
 
-#ifndef LIBFUZZER
-int main(int argc, char *argv[]) {
-  DeepState_InitOptions(argc, argv);
-  return DeepState_Run();
-}
-#endif

src/lib/DeepState.c

@@ -618,4 +618,10 @@ void __stack_chk_fail(void) {
   __builtin_unreachable();
 }
 
+__attribute__((weak))
+int main(int argc, char *argv[]) {
+  DeepState_InitOptions(argc, argv);
+  return DeepState_Run();
+}
+
 DEEPSTATE_END_EXTERN_C

src/lib/Log.c

@@ -126,6 +126,14 @@ void DeepState_LogFormat(enum DeepState_LogLevel level,
   va_end(args);
 }
 
+#pragma clang diagnostic push
+#pragma GCC diagnostic ignored "-Wunknown-warning-option"
+/*#pragma clang diagnostic ignored "-Wbuiltin-declaration-mismatch"
+*/
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wbuiltin-declaration-mismatch"
+
 /* Override libc! */
 DEEPSTATE_NOINLINE
 int puts(const char *str) {
@@ -216,4 +224,7 @@ int __vfprintf_chk(int flag, FILE *file, const char *format, va_list args) {
   return 0;
 }
 
+#pragma clang diagnostic pop
+#pragma GCC diagnostic pop
+
 DEEPSTATE_END_EXTERN_C