[llvm-demangle-fuzzer] Also fuzz microsoftDemangle().

Summary:
Use first byte of input to determine whether to call itaniumDemangle()
or microsoftDemangle().

Addresses https://bugs.llvm.org/show_bug.cgi?id=39582.

Reviewers: kcc, thakis

Reviewed By: kcc, thakis

Subscribers: mgorny, thakis, erik.pilkington, llvm-commits

Differential Revision: https://reviews.llvm.org/D54780

llvm-svn: 350534

3 files changed, 53 insertions, 0 deletions

diff --git a/llvm/tools/llvm-itanium-demangle-fuzzer/CMakeLists.txt b/llvm/tools/llvm-itanium-demangle-fuzzer/CMakeLists.txt
new file mode 100644
index 00000000000..07f02a35b20
--- /dev/null
+++ b/llvm/tools/llvm-itanium-demangle-fuzzer/CMakeLists.txt
@@ -0,0 +1,10 @@
+set(LLVM_LINK_COMPONENTS
+  Demangle
+  FuzzMutate
+  Support
+)
+
+add_llvm_fuzzer(llvm-itanium-demangle-fuzzer
+  llvm-itanium-demangle-fuzzer.cpp
+  DUMMY_MAIN DummyDemanglerFuzzer.cpp
+  )
diff --git a/llvm/tools/llvm-itanium-demangle-fuzzer/DummyDemanglerFuzzer.cpp b/llvm/tools/llvm-itanium-demangle-fuzzer/DummyDemanglerFuzzer.cpp
new file mode 100644
index 00000000000..a2bf9f1b807
--- /dev/null
+++ b/llvm/tools/llvm-itanium-demangle-fuzzer/DummyDemanglerFuzzer.cpp
@@ -0,0 +1,19 @@
+//===--- DummyDemanglerMain.cpp - Entry point to sanity check the fuzzer --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implementation of main so we can build and test without linking libFuzzer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/FuzzMutate/FuzzerCLI.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size);
+int main(int argc, char *argv[]) {
+  return llvm::runFuzzerOnInputs(argc, argv, LLVMFuzzerTestOneInput);
+}
diff --git a/llvm/tools/llvm-itanium-demangle-fuzzer/llvm-itanium-demangle-fuzzer.cpp b/llvm/tools/llvm-itanium-demangle-fuzzer/llvm-itanium-demangle-fuzzer.cpp
new file mode 100644
index 00000000000..07c290a0be5
--- /dev/null
+++ b/llvm/tools/llvm-itanium-demangle-fuzzer/llvm-itanium-demangle-fuzzer.cpp
@@ -0,0 +1,24 @@
+//===--- llvm-demangle-fuzzer.cpp - Fuzzer for the Itanium Demangler ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Demangle/Demangle.h"
+
+#include <cstdint>
+#include <cstdlib>
+#include <string>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  std::string NullTerminatedString((const char *)Data, Size);
+  int status = 0;
+  if (char *demangle = llvm::itaniumDemangle(NullTerminatedString.c_str(), nullptr,
+                                         nullptr, &status))
+    free(demangle);
+
+  return 0;
+}