Refactor contract ABI Utils a bit to get it to build with solc ossfuzz. Untested.

test/tools/ossfuzz/CMakeLists.txt

@@ -29,6 +29,7 @@ if (OSSFUZZ)
             ../../TestCaseReader.cpp
             ../../EVMHost.cpp
             SolidityEvmoneInterface.cpp
+            ../../libsolidity/util/ContractABIUtils.cpp
     )
     target_link_libraries(solc_ossfuzz PRIVATE libsolc evmasm evmc evmone-standalone)
     set_target_properties(solc_ossfuzz PROPERTIES LINK_FLAGS ${LIB_FUZZING_ENGINE})

test/tools/ossfuzz/SolidityEvmoneInterface.cpp

@@ -23,6 +23,7 @@
 
 #include <range/v3/algorithm/all_of.hpp>
 #include <range/v3/span.hpp>
+#include <random>
 
 using namespace solidity::test::fuzzer;
 using namespace solidity::frontend;
@@ -74,6 +75,20 @@ optional<string> SolidityCompilationFramework::noInputFunction()
 	return {};
 }
 
+optional<Json::Value> SolidityCompilationFramework::randomFunction()
+{
+	Json::Value const& contractABI = m_compiler.contractABI(m_compiler.lastContractName());
+	unsigned numFunctions = contractABI.size();
+	if (numFunctions == 0)
+		return {};
+	else
+	{
+		uniform_int_distribution<unsigned> d(0, contractABI.size());
+		minstd_rand r(contractABI.size());
+		return contractABI[d(r)];
+	}
+}
+
 bool EvmoneUtility::zeroWord(uint8_t const* _result, size_t _length)
 {
 	return _length == 32 &&

test/tools/ossfuzz/SolidityEvmoneInterface.h

@@ -100,6 +100,9 @@ public:
 	/// @returns name of a public/external method that does not contain
 	/// input parameters in its signature.
 	std::optional<std::string> noInputFunction();
+	/// @returns FunctionABI of a randomly chosen external function in
+	/// current contract.
+	std::optional<Json::Value> randomFunction();
 	/// @returns name of the last contract in source unit.
 	std::string lastContractName()
 	{
@@ -178,6 +181,10 @@ public:
 	{
 		return m_compilationFramework.noInputFunction();
 	}
+	std::optional<Json::Value> randomFunction()
+	{
+		return m_compilationFramework.randomFunction();
+	}
 	void optSetting(frontend::OptimiserSettings _opt)
 	{
 		m_compilationFramework.optSetting(_opt);

test/tools/ossfuzz/solc_ossfuzz.cpp

@@ -22,6 +22,8 @@
 
 #include <test/TestCaseReader.h>
 
+#include <libsolidity/util/ContractABIUtils.h>
+
 #include <libyul/backends/evm/EVMCodeTransform.h>
 
 #include <liblangutil/EVMVersion.h>
@@ -84,6 +86,8 @@ extern "C" int LLVMFuzzerTestOneInput(uint8_t const* _data, size_t _size)
 				return 0;
 
 			optional<string> noInputFunction = evmoneUtil.noInputFunction();
+			if (auto r = evmoneUtil.randomFunction(); r.has_value())
+				cout << ContractABIUtils{}.functionSignatureFromABI(r.value()) << endl;
 			if (noInputFunction.has_value())
 				evmoneUtil.methodName(noInputFunction.value());
 			else