[libFuzzer] Add support for Fuchsia OS.

Summary:
This patch adds the initial support for Fuchsia.

- LIBFUZZER_FUCHSIA is added as an OS type in FuzzerDefs.h
- Fuchsia is, by design, not POSIX compliant. However, it does use ELF and
  supports common POSIX I/O functions. Thus, FuzzerExtFunctions.h and
  FuzzerIO.h are implemented by extending the header guards in
  FuzzerExtFunctionsWeak.cpp and FuzzerIOPosix.cpp to include
  LIBFUZZER_FUCHSIA.
- The platform-specific portions of FuzzerUtil.h are implemented by
  FuzzerUtilFuchsia.cpp, which makes use of exception ports, syscalls, and
  the launchpad library.
- The experimental equivalence server is not currently supported, so
  FuzzerShmem.h is implemented by stub methods in FuzzerShmemFuchsia.cpp.
  Any future implementation will likely involve VMOs.

Tested with ASAN/SanCov on Fuchsia/x86-64 with the canonical toy fuzzer.

Patch By: aarongreen

Reviewers: kcc, morehouse, flowerhack, phosek

Reviewed By: kcc, phosek, Eugene.Zelenko

Subscribers: srhines, mgorny, Eugene.Zelenko

Differential Revision: https://reviews.llvm.org/D40974

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@320210 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 38 insertions, 0 deletions

diff --git a/lib/fuzzer/FuzzerShmemFuchsia.cpp b/lib/fuzzer/FuzzerShmemFuchsia.cpp
new file mode 100644
index 000000000..e9ce50c2a
--- /dev/null
+++ b/lib/fuzzer/FuzzerShmemFuchsia.cpp
@@ -0,0 +1,38 @@
+//===- FuzzerShmemPosix.cpp - Posix shared memory ---------------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// SharedMemoryRegion.  For Fuchsia, this is just stubs as equivalence servers
+// are not currently supported.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+
+#if LIBFUZZER_FUCHSIA
+
+#include "FuzzerShmem.h"
+
+namespace fuzzer {
+
+bool SharedMemoryRegion::Create(const char *Name) {
+  return false;
+}
+
+bool SharedMemoryRegion::Open(const char *Name) {
+  return false;
+}
+
+bool SharedMemoryRegion::Destroy(const char *Name) {
+  return false;
+}
+
+void SharedMemoryRegion::Post(int Idx) {}
+
+void SharedMemoryRegion::Wait(int Idx) {}
+
+}  // namespace fuzzer
+
+#endif  // LIBFUZZER_FUCHSIA