4 files changed, 168 insertions, 0 deletions
diff --git a/tools/clang-fuzzer/proto-to-cxx/CMakeLists.txt b/tools/clang-fuzzer/proto-to-cxx/CMakeLists.txt
new file mode 100644
index 000000000000..910b793e0e0d
--- /dev/null
+++ b/tools/clang-fuzzer/proto-to-cxx/CMakeLists.txt
@@ -0,0 +1,14 @@
+set(LLVM_LINK_COMPONENTS ${LLVM_TARGETS_TO_BUILD})
+set(CMAKE_CXX_FLAGS ${CXX_FLAGS_NOFUZZ})
+
+# Hack to bypass LLVM's CMake source checks so we can have both a library and
+# an executable built from this directory.
+set(LLVM_OPTIONAL_SOURCES proto_to_cxx.cpp proto_to_cxx_main.cpp)
+
+add_clang_library(clangProtoToCXX proto_to_cxx.cpp
+                  DEPENDS clangCXXProto
+                  LINK_LIBS clangCXXProto ${PROTOBUF_LIBRARIES}
+                  )
+
+add_clang_executable(clang-proto-to-cxx proto_to_cxx_main.cpp)
+target_link_libraries(clang-proto-to-cxx PRIVATE clangProtoToCXX)
diff --git a/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx.cpp b/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx.cpp
new file mode 100644
index 000000000000..cd75e0c99c47
--- /dev/null
+++ b/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx.cpp
@@ -0,0 +1,102 @@
+//==-- proto_to_cxx.cpp - Protobuf-C++ conversion --------------------------==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements functions for converting between protobufs and C++.
+//
+//===----------------------------------------------------------------------===//
+
+#include "proto_to_cxx.h"
+#include "cxx_proto.pb.h"
+
+#include <ostream>
+#include <sstream>
+
+namespace clang_fuzzer {
+
+// Forward decls.
+std::ostream &operator<<(std::ostream &os, const BinaryOp &x);
+std::ostream &operator<<(std::ostream &os, const StatementSeq &x);
+
+// Proto to C++.
+std::ostream &operator<<(std::ostream &os, const Const &x) {
+  return os << "(" << x.val() << ")";
+}
+std::ostream &operator<<(std::ostream &os, const VarRef &x) {
+  return os << "a[" << (static_cast<uint32_t>(x.varnum()) % 100) << "]";
+}
+std::ostream &operator<<(std::ostream &os, const Lvalue &x) {
+  return os << x.varref();
+}
+std::ostream &operator<<(std::ostream &os, const Rvalue &x) {
+    if (x.has_varref()) return os << x.varref();
+    if (x.has_cons())   return os << x.cons();
+    if (x.has_binop())  return os << x.binop();
+    return os << "1";
+}
+std::ostream &operator<<(std::ostream &os, const BinaryOp &x) {
+  os << "(" << x.left();
+  switch (x.op()) {
+    case BinaryOp::PLUS: os << "+"; break;
+    case BinaryOp::MINUS: os << "-"; break;
+    case BinaryOp::MUL: os << "*"; break;
+    case BinaryOp::DIV: os << "/"; break;
+    case BinaryOp::MOD: os << "%"; break;
+    case BinaryOp::XOR: os << "^"; break;
+    case BinaryOp::AND: os << "&"; break;
+    case BinaryOp::OR: os << "|"; break;
+    case BinaryOp::EQ: os << "=="; break;
+    case BinaryOp::NE: os << "!="; break;
+    case BinaryOp::LE: os << "<="; break;
+    case BinaryOp::GE: os << ">="; break;
+    case BinaryOp::LT: os << "<"; break;
+    case BinaryOp::GT: os << ">"; break;
+  }
+  return os << x.right() << ")";
+}
+std::ostream &operator<<(std::ostream &os, const AssignmentStatement &x) {
+  return os << x.lvalue() << "=" << x.rvalue() << ";\n";
+}
+std::ostream &operator<<(std::ostream &os, const IfElse &x) {
+  return os << "if (" << x.cond() << "){\n"
+            << x.if_body() << "} else { \n"
+            << x.else_body() << "}\n";
+}
+std::ostream &operator<<(std::ostream &os, const While &x) {
+  return os << "while (" << x.cond() << "){\n" << x.body() << "}\n";
+}
+std::ostream &operator<<(std::ostream &os, const Statement &x) {
+  if (x.has_assignment()) return os << x.assignment();
+  if (x.has_ifelse())     return os << x.ifelse();
+  if (x.has_while_loop()) return os << x.while_loop();
+  return os << "(void)0;\n";
+}
+std::ostream &operator<<(std::ostream &os, const StatementSeq &x) {
+  for (auto &st : x.statements()) os << st;
+  return os;
+}
+std::ostream &operator<<(std::ostream &os, const Function &x) {
+  return os << "void foo(int *a) {\n" << x.statements() << "}\n";
+}
+
+// ---------------------------------
+
+std::string FunctionToString(const Function &input) {
+  std::ostringstream os;
+  os << input;
+  return os.str();
+
+}
+std::string ProtoToCxx(const uint8_t *data, size_t size) {
+  Function message;
+  if (!message.ParseFromArray(data, size))
+    return "#error invalid proto\n";
+  return FunctionToString(message);
+}
+
+} // namespace clang_fuzzer
diff --git a/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx.h b/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx.h
new file mode 100644
index 000000000000..1985e91ba2cd
--- /dev/null
+++ b/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx.h
@@ -0,0 +1,22 @@
+//==-- proto_to_cxx.h - Protobuf-C++ conversion ----------------------------==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines functions for converting between protobufs and C++.
+//
+//===----------------------------------------------------------------------===//
+
+#include <cstdint>
+#include <cstddef>
+#include <string>
+
+namespace clang_fuzzer {
+class Function;
+std::string FunctionToString(const Function &input);
+std::string ProtoToCxx(const uint8_t *data, size_t size);
+}
diff --git a/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx_main.cpp b/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx_main.cpp
new file mode 100644
index 000000000000..73ef14b75589
--- /dev/null
+++ b/tools/clang-fuzzer/proto-to-cxx/proto_to_cxx_main.cpp
@@ -0,0 +1,30 @@
+//==-- proto_to_cxx_main.cpp - Driver for protobuf-C++ conversion ----------==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements a simple driver to print a C++ program from a protobuf.
+//
+//===----------------------------------------------------------------------===//
+#include <fstream>
+#include <iostream>
+#include <streambuf>
+#include <string>
+
+#include "proto_to_cxx.h"
+
+int main(int argc, char **argv) {
+  for (int i = 1; i < argc; i++) {
+    std::fstream in(argv[i]);
+    std::string str((std::istreambuf_iterator<char>(in)),
+                    std::istreambuf_iterator<char>());
+    std::cout << "// " << argv[i] << std::endl;
+    std::cout << clang_fuzzer::ProtoToCxx(
+        reinterpret_cast<const uint8_t *>(str.data()), str.size());
+  }
+}
+