LLVM  6.0.0svn
FuzzerExtFunctionsWeak.cpp
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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 
42 #define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN) \
43  this->NAME = ::NAME; \
44  CheckFnPtr(reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(::NAME)), \
45  #NAME, WARN);
46 
47 #include "FuzzerExtFunctions.def"
48 
49 #undef EXT_FUNC
50 }
51 
52 } // namespace fuzzer
53 
54 #endif // LIBFUZZER_LINUX
void Printf(const char *Fmt,...)
Definition: FuzzerIO.cpp:112