ceph/src/jaegertracing/opentelemetry-cpp/third_party/nlohmann-json/test/thirdparty/Fuzzer/FuzzerExtFunctionsWeak.cpp

   1 //===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 // Implementation for Linux. This relies on the linker's support for weak
  10 // symbols. We don't use this approach on Apple platforms because it requires
  11 // clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow
  12 // weak symbols to be undefined. That is a complication we don't want to expose
  13 // to clients right now.
  14 //===----------------------------------------------------------------------===//
  15 #include "FuzzerDefs.h"
  16 #if LIBFUZZER_LINUX
  17
  18 #include "FuzzerExtFunctions.h"
  19 #include "FuzzerIO.h"
  20
  21 extern "C" {
  22 // Declare these symbols as weak to allow them to be optionally defined.
  23 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
  24   __attribute__((weak)) RETURN_TYPE NAME FUNC_SIG
  25
  26 #include "FuzzerExtFunctions.def"
  27
  28 #undef EXT_FUNC
  29 }
  30
  31 using namespace fuzzer;
  32
  33 static void CheckFnPtr(void *FnPtr, const char *FnName, bool WarnIfMissing) {
  34   if (FnPtr == nullptr && WarnIfMissing) {
  35     Printf("WARNING: Failed to find function \"%s\".\n", FnName);
  36   }
  37 }
  38
  39 namespace fuzzer {
  40
  41 ExternalFunctions::ExternalFunctions() {
  42 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
  43   this->NAME = ::NAME;                                                         \
  44   CheckFnPtr((void *)::NAME, #NAME, WARN);
  45
  46 #include "FuzzerExtFunctions.def"
  47
  48 #undef EXT_FUNC
  49 }
  50
  51 } // namespace fuzzer
  52
  53 #endif // LIBFUZZER_LINUX