1//===- FuzzerExtFunctionsWeakAlias.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 using weak aliases. Works for Windows.
10//===----------------------------------------------------------------------===//
11#include "FuzzerDefs.h"
12#if LIBFUZZER_WINDOWS
13
14#include "FuzzerExtFunctions.h"
15#include "FuzzerIO.h"
16
17using namespace fuzzer;
18
19extern "C" {
20// Declare these symbols as weak to allow them to be optionally defined.
21#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
22  RETURN_TYPE NAME##Def FUNC_SIG {                                             \
23    Printf("ERROR: Function \"%s\" not defined.\n", #NAME);                    \
24    exit(1);                                                                   \
25  }                                                                            \
26  RETURN_TYPE NAME FUNC_SIG __attribute__((weak, alias(#NAME "Def")));
27
28#include "FuzzerExtFunctions.def"
29
30#undef EXT_FUNC
31}
32
33template <typename T>
34static T *GetFnPtr(T *Fun, T *FunDef, const char *FnName, bool WarnIfMissing) {
35  if (Fun == FunDef) {
36    if (WarnIfMissing)
37      Printf("WARNING: Failed to find function \"%s\".\n", FnName);
38    return nullptr;
39  }
40  return Fun;
41}
42
43namespace fuzzer {
44
45ExternalFunctions::ExternalFunctions() {
46#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
47  this->NAME = GetFnPtr<decltype(::NAME)>(::NAME, ::NAME##Def, #NAME, WARN);
48
49#include "FuzzerExtFunctions.def"
50
51#undef EXT_FUNC
52}
53
54} // namespace fuzzer
55
56#endif // LIBFUZZER_WINDOWS
57