Fuzzing setup

test/EVMHost.cpp

@@ -790,11 +790,19 @@ string EVMHostPrinter::state()
 	return m_stateStream.str();
 }
 
+string EVMHostPrinter::storageOnly()
+{
+	if (m_host.account_exists(m_account))
+		storage();
+	return m_stateStream.str();
+}
+
 void EVMHostPrinter::storage()
 {
 	for (auto const& [slot, value]: m_host.get_address_storage(m_account))
 		if (m_host.get_storage(m_account, slot))
-			m_stateStream << m_host.convertFromEVMC(slot)
+			m_stateStream << "  "
+				<< m_host.convertFromEVMC(slot)
 				<< ": "
 				<< m_host.convertFromEVMC(value.value)
 				<< endl;

test/EVMHost.h

@@ -123,6 +123,8 @@ public:
 	{}
 	/// @returns state at account maintained by host.
 	std::string state();
+	/// @returns storage at account maintained by host.
+	std::string storageOnly();
 private:
 	/// Outputs storage at account to stateStream.
 	void storage();

test/tools/ossfuzz/CMakeLists.txt

@@ -16,6 +16,7 @@ if (OSSFUZZ)
             yul_proto_diff_ossfuzz
             yul_proto_diff_custom_mutate_ossfuzz
             stack_reuse_codegen_ossfuzz
+            yul_evm_diff_ossfuzz
     )
 
     add_custom_target(ossfuzz_abiv2)
@@ -132,6 +133,38 @@ if (OSSFUZZ)
             -Wno-zero-length-array
             -Wno-suggest-destructor-override
     )
+    
+    add_executable(yul_evm_diff_ossfuzz
+            YulToEvmDifferentialFuzzer.cpp
+            ../../libyul/YulOptimizerTestCommon.cpp
+            protoToYul.cpp
+            yulProto.pb.cc
+            ../../EVMHost.cpp
+            YulEvmoneInterface.cpp
+            yulFuzzerCommon.cpp
+    )
+    target_include_directories(yul_evm_diff_ossfuzz PRIVATE
+            /usr/include/libprotobuf-mutator
+    )
+    target_link_libraries(yul_evm_diff_ossfuzz PRIVATE
+            yul
+            yulInterpreter
+            evmc
+            evmone-standalone
+            protobuf-mutator-libfuzzer.a
+            protobuf-mutator.a
+            protobuf.a
+    )
+    set_target_properties(yul_evm_diff_ossfuzz PROPERTIES LINK_FLAGS ${LIB_FUZZING_ENGINE})
+    target_compile_options(yul_evm_diff_ossfuzz PUBLIC
+            ${COMPILE_OPTIONS}
+            -Wno-sign-conversion
+            -Wno-inconsistent-missing-destructor-override
+            -Wno-unused-parameter
+            -Wno-zero-length-array
+            -Wno-suggest-destructor-override
+    )
+
 
     add_executable(abiv2_proto_ossfuzz
             ../../EVMHost.cpp

test/tools/ossfuzz/StackReuseCodegenFuzzer.cpp

@@ -59,25 +59,41 @@ DEFINE_PROTO_FUZZER(Program const& _input)
 		filterStatefulInstructions,
 		filterUnboundedLoops
 	);
-	string yul_source = converter.programToString(_input);
+	string yulSubObject = converter.programToString(_input);
 	// Fuzzer also fuzzes the EVM version field.
 	langutil::EVMVersion version = converter.version();
 	EVMHost hostContext(version, evmone);
 	hostContext.reset();
 
+	// Do not proceed with tests that are too large. 1200 is an arbitrary
+	// threshold.
+	if (yulSubObject.size() > 1200)
+		return;
+
+	YulStringRepository::reset();
+
+	// Package test case into a sub-object
+	solidity::util::Whiskers yulObjectFormat(R"(
+object "main" {
+	code {
+		codecopy(0, dataoffset("deployed"), datasize("deployed"))
+		return(0, datasize("deployed"))
+	}
+	object "deployed" {
+		code {
+			<fuzzerInput>
+		}
+	}
+}
+	)");
+	string yul_source = yulObjectFormat("fuzzerInput", yulSubObject).render();
+
 	if (const char* dump_path = getenv("PROTO_FUZZER_DUMP_PATH"))
 	{
 		ofstream of(dump_path);
 		of.write(yul_source.data(), static_cast<streamsize>(yul_source.size()));
 	}
 
-	// Do not proceed with tests that are too large. 1200 is an arbitrary
-	// threshold.
-	if (yul_source.size() > 1200)
-		return;
-
-	YulStringRepository::reset();
-
 	solidity::frontend::OptimiserSettings settings = solidity::frontend::OptimiserSettings::full();
 	settings.runYulOptimiser = false;
 	settings.optimizeStackAllocation = false;
@@ -93,7 +109,10 @@ DEFINE_PROTO_FUZZER(Program const& _input)
 
 	evmc::result deployResult = YulEvmoneUtility{}.deployCode(unoptimisedByteCode, hostContext);
 	if (deployResult.status_code != EVMC_SUCCESS)
+	{
+		cout << "Deploy unoptimised failed." << endl;
 		return;
+	}
 	auto callMessage = YulEvmoneUtility{}.callMessage(deployResult.create_address);
 	evmc::result callResult = hostContext.call(callMessage);
 	// If the fuzzer synthesized input does not contain the revert opcode which
@@ -112,13 +131,17 @@ DEFINE_PROTO_FUZZER(Program const& _input)
 		);
 	// Bail out on serious errors encountered during a call.
 	if (YulEvmoneUtility{}.seriousCallError(callResult.status_code))
+	{
+		cout << "Unoptimised call failed." << endl;
 		return;
+	}
 	solAssert(
 		(callResult.status_code == EVMC_SUCCESS ||
 		(!noRevertInSource && callResult.status_code == EVMC_REVERT) ||
 		(!noInvalidInSource && callResult.status_code == EVMC_INVALID_INSTRUCTION)),
 		"Unoptimised call failed."
 	);
+
 	ostringstream unoptimizedState;
 	unoptimizedState << EVMHostPrinter{hostContext, deployResult.create_address}.state();
 
@@ -162,18 +185,11 @@ DEFINE_PROTO_FUZZER(Program const& _input)
 	ostringstream optimizedState;
 	optimizedState << EVMHostPrinter{hostContext, deployResultOpt.create_address}.state();
 
-	int64_t constexpr tolerance = 1000;
-	if (callResult.gas_left > callResultOpt.gas_left)
-		if (callResult.gas_left - callResultOpt.gas_left > tolerance)
-		{
-			cout << "Gas differential " << callResult.gas_left - callResultOpt.gas_left << endl;
-			cout << "Unoptimised bytecode" << endl;
-			cout << util::toHex(unoptimisedByteCode) << endl;
-			cout << "Optimised bytecode" << endl;
-			cout << util::toHex(optimisedByteCode) << endl;
-			solAssert(false, "Optimised code consumed more than +1000 gas.");
-		}
-
+	if (unoptimizedState.str() != optimizedState.str())
+	{
+		cout << unoptimizedState.str() << endl;
+		cout << optimizedState.str() << endl;
+	}
 	solAssert(
 		unoptimizedState.str() == optimizedState.str(),
 		"State of unoptimised and optimised stack reused code do not match."

test/tools/ossfuzz/YulEvmoneInterface.cpp

@@ -48,24 +48,8 @@ evmc::result YulEvmoneUtility::deployCode(bytes const& _input, EVMHost& _host)
 		_input.size() <= 0xffff,
 		"Deployed byte code is larger than the permissible 65535 bytes."
 	);
-	uint8_t inputSizeHigher = static_cast<uint8_t>(_input.size() >> 8);
-	uint8_t inputSizeLower = _input.size() & 0xff;
-	/*
-	 * CODESIZE
-	 * PUSH0 0xc
-	 * PUSH0 0x0
-	 * CODECOPY
-	 * PUSH1 <INPUTSIZE>
-	 * PUSH0 0x0
-	 * RETURN
-	 */
-	bytes deployCode = bytes{
-		0x38, 0x60, 0x0c, 0x60, 0x00, 0x39, 0x61,
-		inputSizeHigher, inputSizeLower,
-		0x60, 0x00, 0xf3
-	} + _input;
-	msg.input_data = deployCode.data();
-	msg.input_size = deployCode.size();
+	msg.input_data = _input.data();
+	msg.input_size = _input.size();
 	msg.kind = EVMC_CREATE;
 	return _host.call(msg);
 }

test/tools/ossfuzz/YulToEvmDifferentialFuzzer.cpp

@@ -0,0 +1,193 @@
+/*
+    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/>.
+*/
+
+#include <test/tools/ossfuzz/yulProto.pb.h>
+#include <test/tools/ossfuzz/protoToYul.h>
+#include <test/tools/ossfuzz/yulFuzzerCommon.h>
+
+#include <test/EVMHost.h>
+
+#include <test/tools/ossfuzz/YulEvmoneInterface.h>
+
+#include <test/libyul/YulOptimizerTestCommon.h>
+
+#include <libyul/Exceptions.h>
+
+#include <libyul/backends/evm/EVMCodeTransform.h>
+#include <libyul/backends/evm/EVMDialect.h>
+
+#include <libyul/AsmPrinter.h>
+
+#include <libevmasm/Instruction.h>
+
+#include <liblangutil/EVMVersion.h>
+
+#include <evmone/evmone.h>
+
+#include <src/libfuzzer/libfuzzer_macro.h>
+
+#include <fstream>
+
+using namespace solidity;
+using namespace solidity::test;
+using namespace solidity::test::fuzzer;
+using namespace solidity::yul;
+using namespace solidity::yul::test;
+using namespace solidity::yul::test::yul_fuzzer;
+using namespace solidity::langutil;
+using namespace solidity::util;
+using namespace std;
+
+static evmc::VM evmone = evmc::VM{evmc_create_evmone()};
+
+DEFINE_PROTO_FUZZER(Program const& _input)
+{
+	// Solidity creates an invalid instruction for subobjects, so we simply
+	// ignore them in this fuzzer.
+	if (_input.has_obj())
+		return;
+	bool filterStatefulInstructions = true;
+	bool filterUnboundedLoops = true;
+	bool filterMemoryWrites = true;
+	ProtoConverter converter(
+		filterStatefulInstructions,
+		filterUnboundedLoops,
+		filterMemoryWrites
+	);
+	string yulSubObject = converter.programToString(_input);
+	// Fuzzer also fuzzes the EVM version field.
+	langutil::EVMVersion version = converter.version();
+	EVMHost hostContext(version, evmone);
+	hostContext.reset();
+
+	// Do not proceed with tests that are too large. 1200 is an arbitrary
+	// threshold.
+	if (yulSubObject.size() > 1200)
+		return;
+
+	YulStringRepository::reset();
+
+	// Package test case into a sub-object
+	Whiskers yulObjectFormat(R"(
+	object "main" {
+		code {
+			codecopy(0, dataoffset("deployed"), datasize("deployed"))
+			return(0, datasize("deployed"))
+		}
+		object "deployed" {
+			code {
+				<fuzzerInput>
+			}
+		}
+	}
+		)");
+	string yul_source = yulObjectFormat("fuzzerInput", yulSubObject).render();
+
+	if (const char* dump_path = getenv("PROTO_FUZZER_DUMP_PATH"))
+	{
+		ofstream of(dump_path);
+		of.write(yul_source.data(), static_cast<streamsize>(yul_source.size()));
+	}
+
+	solidity::frontend::OptimiserSettings settings = solidity::frontend::OptimiserSettings::none();
+	AssemblyStack stackUnoptimized;
+	solAssert(
+		stackUnoptimized.parseAndAnalyze("source", yulSubObject),
+		"Parsing fuzzer generated input failed."
+	);
+	ostringstream unoptimizedState;
+	yulFuzzerUtil::TerminationReason termReason = yulFuzzerUtil::interpret(
+		unoptimizedState,
+		stackUnoptimized.parserResult()->code,
+		EVMDialect::strictAssemblyForEVMObjects(version),
+		true
+	);
+	if (yulFuzzerUtil::resourceLimitsExceeded(termReason))
+		return;
+
+	AssemblyStack stackOptimized;
+	solAssert(
+		stackOptimized.parseAndAnalyze("source", yulSubObject),
+		"Parsing fuzzer generated input failed."
+	);
+	YulOptimizerTestCommon optimizerTest(
+		stackOptimized.parserResult(),
+		EVMDialect::strictAssemblyForEVMObjects(version)
+	);
+	// HACK: Force this to fake stack limit evader for now
+	string step = "fakeStackLimitEvader";
+	optimizerTest.setStep(step);
+//	optimizerTest.setStep(optimizerTest.randomOptimiserStep(_input.step()));
+	shared_ptr<solidity::yul::Block> astBlock = optimizerTest.run();
+	string optimisedProgram = Whiskers(R"(
+	object "main" {
+		code {
+			codecopy(0, dataoffset("deployed"), datasize("deployed"))
+			return(0, datasize("deployed"))
+		}
+		object "deployed" {
+			code {
+				<fuzzerInput>
+			}
+		}
+	}
+		)")
+		("fuzzerInput", AsmPrinter{}(*astBlock))
+		.render();
+	bytes optimisedByteCode;
+	optimisedByteCode = YulAssembler{version, settings, optimisedProgram}.assemble();
+
+	// Reset host before running optimised code.
+	hostContext.reset();
+	evmc::result deployResultOpt = YulEvmoneUtility{}.deployCode(optimisedByteCode, hostContext);
+	solAssert(
+		deployResultOpt.status_code == EVMC_SUCCESS,
+		"Evmone: Optimized contract creation failed"
+	);
+	auto callMessageOpt = YulEvmoneUtility{}.callMessage(deployResultOpt.create_address);
+	evmc::result callResultOpt = hostContext.call(callMessageOpt);
+	bool noRevertInSource = yulSubObject.find("revert") == string::npos;
+	bool noInvalidInSource = yulSubObject.find("invalid") == string::npos;
+	if (noRevertInSource)
+		solAssert(
+			callResultOpt.status_code != EVMC_REVERT,
+			"SolidityEvmoneInterface: EVM One reverted"
+		);
+	if (noInvalidInSource)
+		solAssert(
+			callResultOpt.status_code != EVMC_INVALID_INSTRUCTION,
+			"Invalid instruction."
+		);
+	solAssert(
+		(callResultOpt.status_code == EVMC_SUCCESS ||
+		 (!noRevertInSource && callResultOpt.status_code == EVMC_REVERT) ||
+		 (!noInvalidInSource && callResultOpt.status_code == EVMC_INVALID_INSTRUCTION)),
+		"Optimised call failed."
+	);
+	ostringstream optimizedState;
+	optimizedState << EVMHostPrinter{hostContext, deployResultOpt.create_address}.storageOnly();
+
+	if (unoptimizedState.str() != optimizedState.str())
+	{
+		cout << unoptimizedState.str() << endl;
+		cout << optimizedState.str() << endl;
+	}
+	solAssert(
+		unoptimizedState.str() == optimizedState.str(),
+		"State of unoptimised and optimised stack reused code do not match."
+	);
+}

test/tools/ossfuzz/protoToYul.cpp

@@ -1317,7 +1317,8 @@ void ProtoConverter::visit(Statement const& _x)
 			visit(_x.ifstmt());
 		break;
 	case Statement::kStorageFunc:
-		visit(_x.storage_func());
+		if (!m_filterMemoryWrites || (_x.storage_func().has_st() && _x.storage_func().st() == StoreFunc_Storage_SSTORE))
+			visit(_x.storage_func());
 		break;
 	case Statement::kBlockstmt:
 		if (_x.blockstmt().statements_size() > 0)
@@ -1869,6 +1870,8 @@ void ProtoConverter::visit(Program const& _x)
 	{
 	case Program::kBlock:
 		m_output << "{\n";
+		// TODO: Clean up
+		m_output << "mstore(0x40, memoryguard(0x60))\n";
 		visit(_x.block());
 		m_output << "}\n";
 		break;

test/tools/ossfuzz/protoToYul.h

@@ -41,7 +41,8 @@ class ProtoConverter
 public:
 	ProtoConverter(
 		bool _filterStatefulInstructions = false,
-		bool _filterUnboundedLoops = false
+		bool _filterUnboundedLoops = false,
+		bool _filterMemoryWrites = false
 	)
 	{
 		m_funcVars = std::vector<std::vector<std::vector<std::string>>>{};
@@ -59,6 +60,7 @@ public:
 		m_forInitScopeExtEnabled = true;
 		m_filterStatefulInstructions = _filterStatefulInstructions;
 		m_filterUnboundedLoops = _filterUnboundedLoops;
+		m_filterMemoryWrites = _filterMemoryWrites;
 	}
 	ProtoConverter(ProtoConverter const&) = delete;
 	ProtoConverter(ProtoConverter&&) = delete;
@@ -381,5 +383,8 @@ private:
 	/// Flat that, if set, stops the converter from generating potentially
 	/// unbounded loops.
 	bool m_filterUnboundedLoops;
+	/// Flag that, if set, stops the converter from generating memory
+	/// writes i.e., mstore/mstore8.
+	bool m_filterMemoryWrites;
 };
 }

test/tools/ossfuzz/strictasm_diff_ossfuzz.cpp

@@ -93,8 +93,7 @@ extern "C" int LLVMFuzzerTestOneInput(uint8_t const* _data, size_t _size)
 	termReason = yulFuzzerUtil::interpret(
 		os2,
 		stack.parserResult()->code,
-		EVMDialect::strictAssemblyForEVMObjects(langutil::EVMVersion()),
-		(yul::test::yul_fuzzer::yulFuzzerUtil::maxSteps * 4)
+		EVMDialect::strictAssemblyForEVMObjects(langutil::EVMVersion())
 	);
 
 	if (yulFuzzerUtil::resourceLimitsExceeded(termReason))

test/tools/ossfuzz/yulFuzzerCommon.cpp

@@ -26,6 +26,7 @@ yulFuzzerUtil::TerminationReason yulFuzzerUtil::interpret(
 	ostream& _os,
 	shared_ptr<yul::Block> _ast,
 	Dialect const& _dialect,
+	bool _outputStorageOnly,
 	size_t _maxSteps,
 	size_t _maxTraceSize,
 	size_t _maxExprNesting
@@ -70,7 +71,10 @@ yulFuzzerUtil::TerminationReason yulFuzzerUtil::interpret(
 		reason = TerminationReason::ExplicitlyTerminated;
 	}
 
-	state.dumpTraceAndState(_os);
+	if (_outputStorageOnly)
+		state.dumpStorage(_os);
+	else
+		state.dumpTraceAndState(_os);
 	return reason;
 }
 

test/tools/ossfuzz/yulFuzzerCommon.h

@@ -36,6 +36,7 @@ struct yulFuzzerUtil
 		std::ostream& _os,
 		std::shared_ptr<yul::Block> _ast,
 		Dialect const& _dialect,
+		bool _outputStorageOnly = false,
 		size_t _maxSteps = maxSteps,
 		size_t _maxTraceSize = maxTraceSize,
 		size_t _maxExprNesting = maxExprNesting

test/tools/yulInterpreter/Interpreter.cpp

@@ -48,6 +48,13 @@ using namespace solidity::yul::test;
 
 using solidity::util::h256;
 
+void InterpreterState::dumpStorage(ostream& _out) const
+{
+	for (auto const& slot: storage)
+		if (slot.second != h256{})
+			_out << "  " << slot.first.hex() << ": " << slot.second.hex() << endl;
+}
+
 void InterpreterState::dumpTraceAndState(ostream& _out) const
 {
 	_out << "Trace:" << endl;
@@ -61,9 +68,7 @@ void InterpreterState::dumpTraceAndState(ostream& _out) const
 		if (value != 0)
 			_out << "  " << std::uppercase << std::hex << std::setw(4) << offset << ": " << h256(value).hex() << endl;
 	_out << "Storage dump:" << endl;
-	for (auto const& slot: storage)
-		if (slot.second != h256{})
-			_out << "  " << slot.first.hex() << ": " << slot.second.hex() << endl;
+	dumpStorage(_out);
 }
 
 void Interpreter::run(InterpreterState& _state, Dialect const& _dialect, Block const& _ast)

test/tools/yulInterpreter/Interpreter.h

@@ -99,7 +99,10 @@ struct InterpreterState
 	size_t maxExprNesting = 0;
 	ControlFlowState controlFlowState = ControlFlowState::Default;
 
+	/// Prints execution trace and non-zero storage to @param _out.
 	void dumpTraceAndState(std::ostream& _out) const;
+	/// Prints non-zero storage to @param _out.
+	void dumpStorage(std::ostream& _out) const;
 };
 
 /**