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//===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// 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 "FuzzerPlatform.h"
#if LIBFUZZER_LINUX || LIBFUZZER_NETBSD || LIBFUZZER_FUCHSIA || \
LIBFUZZER_FREEBSD || LIBFUZZER_EMSCRIPTEN
#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, visibility("default"))) 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
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