[clangd] Add a simple fuzzer. It crashes a lot :)

llvm-svn: 316649

clang-tools-extra/clangd/CMakeLists.txt

@@ -28,4 +28,7 @@ add_clang_library(clangDaemon
   ${LLVM_PTHREAD_LIB}
   )
 
+if( LLVM_LIB_FUZZING_ENGINE OR LLVM_USE_SANITIZE_COVERAGE )
+  add_subdirectory(fuzzer)
+endif()
 add_subdirectory(tool)

clang-tools-extra/clangd/fuzzer/CMakeLists.txt

@@ -0,0 +1,23 @@
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/..)
+
+set(LLVM_LINK_COMPONENTS support)
+
+if(LLVM_USE_SANITIZE_COVERAGE)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=fuzzer")
+endif()
+
+add_clang_executable(clangd-fuzzer
+  EXCLUDE_FROM_ALL
+  ClangdFuzzer.cpp
+  )
+
+target_link_libraries(clangd-fuzzer
+  clangBasic
+  clangDaemon
+  clangFormat
+  clangFrontend
+  clangSema
+  clangTooling
+  clangToolingCore
+  ${LLVM_LIB_FUZZING_ENGINE}
+  )

clang-tools-extra/clangd/fuzzer/ClangdFuzzer.cpp

@@ -0,0 +1,34 @@
+//===-- ClangdFuzzer.cpp - Fuzz clangd ------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file implements a function that runs clangd on a single input.
+/// This function is then linked into the Fuzzer library.
+///
+//===----------------------------------------------------------------------===//
+
+#include "ClangdLSPServer.h"
+#include "llvm/Support/Program.h"
+#include <sstream>
+
+extern "C" int LLVMFuzzerTestOneInput(uint8_t *data, size_t size) {
+  /// Change stdin to binary to not lose \r\n on windows.
+  llvm::sys::ChangeStdinToBinary();
+
+  clang::clangd::JSONOutput Out(llvm::nulls(), llvm::nulls(), nullptr);
+
+  /// Initialize and run ClangdLSPServer.
+  clang::clangd::ClangdLSPServer LSPServer(
+      Out, clang::clangd::getDefaultAsyncThreadsCount(),
+      /*EnableSnippets=*/false, llvm::None, llvm::None);
+
+  std::istringstream In(std::string(reinterpret_cast<char *>(data), size));
+  LSPServer.run(In);
+  return 0;
+}