ossfuzz: Add sol proto fuzzer skeleton

Co-Authored-By: Leonardo <leo@ethereum.org>

test/tools/ossfuzz/protoToSol.h

@@ -0,0 +1,185 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#pragma once
+
+#include <test/tools/ossfuzz/solProto.pb.h>
+
+#include <random>
+#include <string>
+#include <utility>
+#include <variant>
+
+namespace solidity::test::solprotofuzzer
+{
+/// Random number generator that is seeded with a fuzzer
+/// supplied unsigned integer.
+struct SolRandomNumGenerator
+{
+	using RandomEngine = std::minstd_rand;
+
+	explicit SolRandomNumGenerator(unsigned _seed): m_random(RandomEngine(_seed)) {}
+
+	/// @returns a pseudo random unsigned integer
+	unsigned operator()()
+	{
+		return m_random();
+	}
+
+	RandomEngine m_random;
+};
+
+/* There are two types of tests created by the converter:
+ * - library test
+ * - contract test
+ *
+ * The template for library test is the following:
+ *
+ * // Library generated from fuzzer protobuf specification
+ * library L0 {
+ *      function f0(uint) public view returns (uint) {
+ *          return 31337;
+ *      }
+ *      function f1(uint) public pure returns (uint) {
+ *          return 455;
+ *      }
+ * }
+ * library L1 {
+ *      function f0(uint) external view returns (uint) {
+ *          return 607;
+ *      }
+ * }
+ *
+ * // Test entry point
+ * contract C {
+ *     // Uses a single pseudo randomly chosen library
+ *     // and calls a pseudo randomly chosen function
+ *     // returning a non-zero error code on failure or
+ *     // a zero uint when test passes.
+ *     using L0 for uint;
+ *     function test() public pure returns (uint) {
+ *          uint x;
+ *          if (x.f1() != 455)
+ *              return 1;
+ *          return 0;
+ *     }
+ * }
+ *
+ * The template for contract test is the following
+ * // Contracts generated from fuzzer protobuf specification
+ * contract C0B {
+ *      function f0() public pure virtual returns (uint)
+ *      {
+ *          return 42;
+ *      }
+ * }
+ * contract C0 is C0B {
+ *      function f0() public pure override returns (uint)
+ *      {
+ *          return 1337;
+ *      }
+ * }
+ *
+ * // Test entry point
+ * contract C {
+ *      // Invokes one or more contract functions returning
+ *      // a non-zero error code for failure, a zero uint
+ *      // when all tests pass
+ *      function test() public pure returns (uint)
+ *      {
+ *          C0 tc0 = new C0();
+ *          if (tc0.f0() != 1337)
+ *              return 1;
+ *          C0B tc1 = new C0B();
+ *          if (tc1.f0() != 42)
+ *              return 2;
+ *          // Expected return value if all tests pass
+ *          return 0;
+ *      }
+ * }
+ */
+class ProtoConverter
+{
+public:
+	ProtoConverter() {}
+	ProtoConverter(ProtoConverter const&) = delete;
+	ProtoConverter(ProtoConverter&&) = delete;
+	std::string protoToSolidity(Program const&);
+	/// @returns true if test calls a library function, false
+	/// otherwise
+	bool libraryTest() const;
+	/// @returns name of the library under test
+	std::string libraryName() const;
+private:
+	/// Variant type that points to one of contract, interface, library protobuf messages
+	using CIL = std::variant<Contract const*, Interface const*, Library const*>;
+	/// Protobuf message visitors that accept a const reference to a protobuf message
+	/// type and return its solidity translation.
+	std::string visit(Program const&);
+	std::string visit(TestContract const&);
+	std::string visit(ContractType const&);
+	std::string visit(Interface const& _interface);
+	std::string visit(Library const& _library);
+	std::string visit(Contract const& _contract);
+	/// @returns a string pair containing a library declaration (relevant for library
+	/// tests only) and a solidity test case
+	std::pair<std::string, std::string> generateTestCase(TestContract const& _testContract);
+	/// @returns name of a program i.e., contract, library or interface
+	std::string programName(CIL _program);
+	/// @returns a tuple containing the names of the library and function under
+	/// test, and its expected output.
+	std::tuple<std::string, std::string, std::string> pseudoRandomLibraryTest();
+	/// Performs bookkeeping for a fuzzer-supplied program
+	void openProgramScope(CIL _program);
+	/// @returns a deterministic pseudo random unsigned integer
+	unsigned randomNumber();
+	/// @returns true if fuzzer supplied Library protobuf message
+	/// contains zero functions, false otherwise.
+	static bool emptyLibrary(Library const& _library)
+	{
+		return _library.funcdef_size() == 0;
+	}
+	/// @returns true if there are no valid library test cases, false
+	/// otherwise.
+	bool emptyLibraryTests()
+	{
+		return m_libraryTests.size() == 0;
+	}
+	/// @returns true if there are no valid contract test cases, false
+	/// otherwise.
+	bool emptyContractTests()
+	{
+		return m_contractTests.size() == 0;
+	}
+	/// Numeric suffix that is part of program names e.g., "0" in "C0"
+	unsigned m_programNumericSuffix = 0;
+	/// Flag that states whether library call is tested (true) or not (false).
+	bool m_libraryTest = false;
+	/// A smart pointer to fuzzer driven random number generator
+	std::shared_ptr<SolRandomNumGenerator> m_randomGen;
+	/// Maps protobuf program to its string name
+	std::map<CIL, std::string> m_programNameMap;
+	/// List of tuples containing library name, function and its expected output
+	std::vector<std::tuple<std::string, std::string, std::string>> m_libraryTests;
+	/// Maps contract name to a map of function names and their expected output
+	std::map<std::string, std::map<std::string, std::string>> m_contractTests;
+	/// Name of the library under test, relevant if m_libraryTest is set
+	std::string m_libraryName;
+	/// Maximum number of local variables in test function to avoid stack too deep
+	/// errors
+	static unsigned constexpr s_maxVars = 15;
+};
+}