[LibFuzzer] Declare and use sanitizer functions in ``fuzzer::ExternalFunctions``

This fixes linking problems on OSX.

Unfortunately it turns out we need to use an instance of the
``fuzzer::ExternalFunctions`` object in several places so this
commit also replaces all instances with a single global instance.

It also turns out initializing a global ``fuzzer::ExternalFunctions``
before main is entered (i.e. letting the object be initialised by the
global initializers) is not safe (on OSX the call to ``Printf()`` in the
CTOR crashes if it is called from a global initializer) so we instead
have a global ``fuzzer::ExternalFunctions*`` and initialize it inside
``FuzzerDriver()``.

Multiple unit tests depend also depend on the
``fuzzer::ExternalFunctions*`` global so a ``main()`` function has been
added that initializes it before running any tests.

Differential Revision: http://reviews.llvm.org/D20943

llvm-svn: 272072

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerDriver.cpp b/llvm/lib/Fuzzer/FuzzerDriver.cpp
index 9807d605aeb..4e980bfd807 100644
--- a/llvm/lib/Fuzzer/FuzzerDriver.cpp
+++ b/llvm/lib/Fuzzer/FuzzerDriver.cpp
@@ -269,9 +269,9 @@ static bool AllInputsAreFiles() {
 int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
   using namespace fuzzer;
   assert(argc && argv && "Argument pointers cannot be nullptr");
-  fuzzer::ExternalFunctions EF;
-  if (EF.LLVMFuzzerInitialize)
-    EF.LLVMFuzzerInitialize(argc, argv);
+  EF = new ExternalFunctions();
+  if (EF->LLVMFuzzerInitialize)
+    EF->LLVMFuzzerInitialize(argc, argv);
   const std::vector<std::string> Args(*argv, *argv + *argc);
   assert(!Args.empty());
   ProgName = new std::string(Args[0]);
@@ -422,4 +422,8 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
 
   exit(0);  // Don't let F destroy itself.
 }
+
+// Storage for global ExternalFunctions object.
+ExternalFunctions *EF = nullptr;
+
 }  // namespace fuzzer