[libFuzzer] Diff 43 - [FuzzerSupport] Use cmake instead of macros for platform specific code.

[mpividori]

We could even remove the header: "Platform.h".
I didn't in case we need it in the future.

[mpividori]

Don't consider my last comment. I realized we still need the macros in UtilPosix.cpp, to consider different cases for Apple and Linux, inside GetPeakRSSMb().

lib/Fuzzer/CMakeLists.txt

 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")
 if( LLVM_USE_SANITIZE_COVERAGE )
   if(NOT "${LLVM_USE_SANITIZER}" STREQUAL "Address")
     message(FATAL_ERROR
       "LibFuzzer and its tests require LLVM_USE_SANITIZER=Address and "
       "LLVM_USE_SANITIZE_COVERAGE=YES to be set."
       )
   endif()
 
   add_subdirectory(Support)
 
+  if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+    set(FUZZER_EXT_FUNCTIONS FuzzerExtFunctionsWeakAlias.cpp)
+  elseif (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+    set(FUZZER_EXT_FUNCTIONS FuzzerExtFunctionsWeak.cpp)
+  elseif (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+    set(FUZZER_EXT_FUNCTIONS FuzzerExtFunctionsDlsym.cpp)
+  endif()
+
   add_library(LLVMFuzzerNoMainObjects OBJECT
     FuzzerCrossOver.cpp
     FuzzerDriver.cpp
-    FuzzerExtFunctionsDlsym.cpp
-    FuzzerExtFunctionsWeak.cpp
-    FuzzerExtFunctionsWeakAlias.cpp
     FuzzerLoop.cpp
     FuzzerMerge.cpp
     FuzzerMutate.cpp
     FuzzerSHA1.cpp
     FuzzerTracePC.cpp
     FuzzerTraceState.cpp
     FuzzerUtil.cpp
+    ${FUZZER_EXT_FUNCTIONS}
     )
   add_library(LLVMFuzzerNoMain STATIC
     $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
     )
   target_link_libraries(LLVMFuzzerNoMain ${PTHREAD_LIB})
   target_link_libraries(LLVMFuzzerNoMain LLVMFuzzerSupport)
   add_library(LLVMFuzzer STATIC
     FuzzerMain.cpp

lib/Fuzzer/FuzzerExtFunctionsDlsym.cpp

 //===- FuzzerExtFunctionsDlsym.cpp - Interface to external functions ------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Implementation for operating systems that support dlsym(). We only use it on
 // Apple platforms for now. We don't use this approach on Linux because it
 // requires that clients of LibFuzzer pass ``--export-dynamic`` to the linker.
 // That is a complication we don't wish to expose to clients right now.
 //===----------------------------------------------------------------------===//
-#include "Support/Platform.h"
-#if LIBFUZZER_APPLE
 
 #include "FuzzerExtFunctions.h"
 #include "Support/UtilIO.h"
 #include <dlfcn.h>
 
 using namespace fuzzer;
 
 template <typename T>
#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
   this->NAME = GetFnPtr<decltype(ExternalFunctions::NAME)>(#NAME, WARN)
 
 #include "FuzzerExtFunctions.def"
 
 #undef EXT_FUNC
 }
 
 } // namespace fuzzer
-
-#endif // LIBFUZZER_APPLE

lib/Fuzzer/FuzzerExtFunctionsWeak.cpp

 //===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Implementation for Linux. This relies on the linker's support for weak
 // symbols. We don't use this approach on Apple platforms because it requires
 // clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow
 // weak symbols to be undefined. That is a complication we don't want to expose
 // to clients right now.
 //===----------------------------------------------------------------------===//
-#include "Support/Platform.h"
-#if LIBFUZZER_LINUX
 
 #include "FuzzerExtFunctions.h"
 #include "Support/UtilIO.h"
 
 extern "C" {
 // Declare these symbols as weak to allow them to be optionally defined.
 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
   __attribute__((weak)) RETURN_TYPE NAME FUNC_SIG
#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
   CheckFnPtr((void *)::NAME, #NAME, WARN);
 
 #include "FuzzerExtFunctions.def"
 
 #undef EXT_FUNC
 }
 
 } // namespace fuzzer
-
-#endif // LIBFUZZER_LINUX

lib/Fuzzer/FuzzerExtFunctionsWeakAlias.cpp

 //===- FuzzerExtFunctionsWeakAlias.cpp - Interface to external functions --===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Implementation using weak aliases. Works for Windows.
 //===----------------------------------------------------------------------===//
-#include "Support/Platform.h"
-#if LIBFUZZER_WINDOWS
 
 #include "FuzzerExtFunctions.h"
 #include "Support/UtilIO.h"
 
 using namespace fuzzer;
 
 extern "C" {
 // Declare these symbols as weak to allow them to be optionally defined.
#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
   this->NAME = GetFnPtr<decltype(::NAME)>(::NAME, ::NAME##Def, #NAME, WARN);
 
 #include "FuzzerExtFunctions.def"
 
 #undef EXT_FUNC
 }
 
 } // namespace fuzzer
-
-#endif // LIBFUZZER_WINDOWS

lib/Fuzzer/Support/CMakeLists.txt

-add_library(LLVMFuzzerSupport STATIC
+set(FUZZER_SUPPORT_SOURCES
   Util.cpp
-  UtilDarwin.cpp
-  UtilLinux.cpp
-  UtilPosix.cpp
-  UtilWindows.cpp
   UtilIO.cpp
-  UtilIOPosix.cpp
+  )
+
+if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+  list(APPEND FUZZER_SUPPORT_SOURCES
+    UtilWindows.cpp
     UtilIOWindows.cpp
   )
+else()
+  list(APPEND FUZZER_SUPPORT_SOURCES
+    UtilPosix.cpp
+    UtilIOPosix.cpp
+  )
+  if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+    list(APPEND FUZZER_SUPPORT_SOURCES
+      UtilLinux.cpp
+    )
+  elseif (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+    list(APPEND FUZZER_SUPPORT_SOURCES
+      UtilDarwin.cpp
+    )
+  endif()
+endif()
+
+add_library(LLVMFuzzerSupport STATIC ${FUZZER_SUPPORT_SOURCES})

lib/Fuzzer/Support/UtilDarwin.cpp

 //===- UtilDarwin.cpp - Misc utils ----------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Misc utils for Darwin.
 //===----------------------------------------------------------------------===//
-#include "Platform.h"
-#if LIBFUZZER_APPLE
 
 #include "UtilIO.h"
 #include <mutex>
 #include <signal.h>
 #include <spawn.h>
 #include <sys/wait.h>
 
 // There is no header for this on macOS so declare here
if (ActiveThreadCount == 0) {
       if (FailedRestore)
         ProcessStatus = -1;
     }
   }
   return ProcessStatus;
 }
 
 } // namespace fuzzer
-
-#endif // LIBFUZZER_APPLE

lib/Fuzzer/Support/UtilIOPosix.cpp

 //===- UtilIOPosix.cpp - IO utils for Posix. ------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // IO functions implementation using Posix API.
 //===----------------------------------------------------------------------===//
-#include "Platform.h"
-#if LIBFUZZER_POSIX
 
 #include "UtilIO.h"
 #include <cstdarg>
 #include <cstdio>
 #include <cstring>
 #include <dirent.h>
 #include <fstream>
 #include <iterator>
std::string DirName(const std::string &FileName) {
   char *Tmp = new char[FileName.size() + 1];
   memcpy(Tmp, FileName.c_str(), FileName.size() + 1);
   std::string Res = dirname(Tmp);
   delete [] Tmp;
   return Res;
 }
 
 }  // namespace fuzzer
-
-#endif // LIBFUZZER_POSIX

lib/Fuzzer/Support/UtilIOWindows.cpp

 //===- UtilIOWindows.cpp - IO utils for Windows. --------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // IO functions implementation for Windows.
 //===----------------------------------------------------------------------===//
-#include "Platform.h"
-#if LIBFUZZER_WINDOWS
 
 #include "UtilIO.h"
 #include <cassert>
 #include <cstdarg>
 #include <cstdio>
 #include <fstream>
 #include <io.h>
 #include <iterator>
if (!DirLen)
       return ".";
     return std::string(".\\").append(FileName, 0, DirLen);
   }
 
   return FileName.substr(0, LocationLen + DirLen);
 }
 
 }  // namespace fuzzer
-
-#endif // LIBFUZZER_WINDOWS

lib/Fuzzer/Support/UtilLinux.cpp

 //===- UtilLinux.cpp - Misc utils for Linux. ------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Misc utils for Linux.
 //===----------------------------------------------------------------------===//
-#include "Platform.h"
-#if LIBFUZZER_LINUX
 
 #include <stdlib.h>
 #include <string>
 
 namespace fuzzer {
 
 int ExecuteCommand(const std::string &Command) {
   return system(Command.c_str());
 }
 
 } // namespace fuzzer
-
-#endif // LIBFUZZER_LINUX

lib/Fuzzer/Support/UtilPosix.cpp

 //===- UtilPosix.cpp - Misc utils for Posix. ------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Misc utils implementation using Posix API.
 //===----------------------------------------------------------------------===//
 #include "Platform.h"
-#if LIBFUZZER_POSIX
 #include "Util.h"
 #include "UtilIO.h"
 #include <cassert>
 #include <chrono>
 #include <cstring>
 #include <errno.h>
 #include <iomanip>
 #include <signal.h>

 }
 
 const void *SearchMemory(const void *Data, size_t DataLen, const void *Patt,
                          size_t PattLen) {
   return memmem(Data, DataLen, Patt, PattLen);
 }
 
 }  // namespace fuzzer
-
-#endif // LIBFUZZER_POSIX

lib/Fuzzer/Support/UtilWindows.cpp

 //===- UtilWindows.cpp - Misc utils for Windows. --------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 // Misc utils implementation for Windows.
 //===----------------------------------------------------------------------===//
-#include "Platform.h"
-#if LIBFUZZER_WINDOWS
+
 #include "Util.h"
 #include "UtilIO.h"
 #include <cassert>
 #include <chrono>
 #include <cstring>
 #include <errno.h>
 #include <iomanip>
 #include <signal.h>
const void *SearchMemory(const void *Data, size_t DataLen, const void *Patt,
   for (const char *It = Cdata; It < End; ++It)
     if (It[0] == Cpatt[0] && memcmp(It, Cpatt, PattLen) == 0)
       return It;
 
   return NULL;
 }
 
 } // namespace fuzzer
-
-#endif // LIBFUZZER_WINDOWS