83 lines
2.8 KiB
C++
83 lines
2.8 KiB
C++
//=== FuzzerExtWindows.cpp - Interface to external functions --------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// Implementation of FuzzerExtFunctions for Windows. Uses alternatename when
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// compiled with MSVC. Uses weak aliases when compiled with clang. Unfortunately
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// the method each compiler supports is not supported by the other.
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//===----------------------------------------------------------------------===//
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#include "FuzzerPlatform.h"
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#if LIBFUZZER_WINDOWS
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#include "FuzzerExtFunctions.h"
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#include "FuzzerIO.h"
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using namespace fuzzer;
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// Intermediate macro to ensure the parameter is expanded before stringified.
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#define STRINGIFY_(A) #A
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#define STRINGIFY(A) STRINGIFY_(A)
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#if LIBFUZZER_MSVC
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// Copied from compiler-rt/lib/sanitizer_common/sanitizer_win_defs.h
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#if defined(_M_IX86) || defined(__i386__)
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#define WIN_SYM_PREFIX "_"
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#else
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#define WIN_SYM_PREFIX
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#endif
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// Declare external functions as having alternativenames, so that we can
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// determine if they are not defined.
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#define EXTERNAL_FUNC(Name, Default) \
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__pragma(comment(linker, "/alternatename:" WIN_SYM_PREFIX STRINGIFY( \
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Name) "=" WIN_SYM_PREFIX STRINGIFY(Default)))
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#else
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// Declare external functions as weak to allow them to default to a specified
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// function if not defined explicitly. We must use weak symbols because clang's
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// support for alternatename is not 100%, see
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// https://bugs.llvm.org/show_bug.cgi?id=40218 for more details.
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#define EXTERNAL_FUNC(Name, Default) \
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__attribute__((weak, alias(STRINGIFY(Default))))
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#endif // LIBFUZZER_MSVC
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extern "C" {
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#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \
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RETURN_TYPE NAME##Def FUNC_SIG { \
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Printf("ERROR: Function \"%s\" not defined.\n", #NAME); \
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exit(1); \
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} \
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EXTERNAL_FUNC(NAME, NAME##Def) RETURN_TYPE NAME FUNC_SIG
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#include "FuzzerExtFunctions.def"
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#undef EXT_FUNC
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}
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template <typename T>
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static T *GetFnPtr(T *Fun, T *FunDef, const char *FnName, bool WarnIfMissing) {
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if (Fun == FunDef) {
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if (WarnIfMissing)
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Printf("WARNING: Failed to find function \"%s\".\n", FnName);
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return nullptr;
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}
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return Fun;
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}
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namespace fuzzer {
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ExternalFunctions::ExternalFunctions() {
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#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \
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this->NAME = GetFnPtr<decltype(::NAME)>(::NAME, ::NAME##Def, #NAME, WARN);
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#include "FuzzerExtFunctions.def"
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#undef EXT_FUNC
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}
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} // namespace fuzzer
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#endif // LIBFUZZER_WINDOWS
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