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Diffstat (limited to 'lib/fuzzer/FuzzerExtFunctionsWeak.cpp')
-rw-r--r-- | lib/fuzzer/FuzzerExtFunctionsWeak.cpp | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/lib/fuzzer/FuzzerExtFunctionsWeak.cpp b/lib/fuzzer/FuzzerExtFunctionsWeak.cpp new file mode 100644 index 000000000..5056eb8a9 --- /dev/null +++ b/lib/fuzzer/FuzzerExtFunctionsWeak.cpp @@ -0,0 +1,54 @@ +//===- 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 "FuzzerDefs.h" +#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD + +#include "FuzzerExtFunctions.h" +#include "FuzzerIO.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 + +#include "FuzzerExtFunctions.def" + +#undef EXT_FUNC +} + +using namespace fuzzer; + +static void CheckFnPtr(void *FnPtr, const char *FnName, bool WarnIfMissing) { + if (FnPtr == nullptr && WarnIfMissing) { + Printf("WARNING: Failed to find function \"%s\".\n", FnName); + } +} + +namespace fuzzer { + +ExternalFunctions::ExternalFunctions() { +#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \ + this->NAME = ::NAME; \ + CheckFnPtr(reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(::NAME)), \ + #NAME, WARN); + +#include "FuzzerExtFunctions.def" + +#undef EXT_FUNC +} + +} // namespace fuzzer + +#endif // LIBFUZZER_LINUX || LIBFUZZER_NETBSD |