Merge pull request #5852 from ethereum/solc-api-cleanup

Introduce solidity_free in libsolc

Changelog.md

@@ -10,6 +10,7 @@ Language Features:
 
 
 Compiler Features:
+ * C API (``libsolc`` / raw ``soljson.js``): Introduce ``solidity_free`` method which releases all internal buffers to save memory.
 
 
 Bugfixes:

libsolc/libsolc.cpp

@@ -98,4 +98,8 @@ extern char const* solidity_compile(char const* _input, CStyleReadFileCallback _
 	s_outputBuffer = compile(_input, _readCallback);
 	return s_outputBuffer.c_str();
 }
+extern void solidity_free() noexcept
+{
+	s_outputBuffer.clear();
+}
 }

libsolc/libsolc.h

@@ -55,6 +55,11 @@ char const* solidity_version() SOLC_NOEXCEPT;
 /// The pointer returned must not be freed by the caller.
 char const* solidity_compile(char const* _input, CStyleReadFileCallback _readCallback) SOLC_NOEXCEPT;
 
+/// Frees up any allocated memory.
+///
+/// NOTE: the pointer returned by solidity_compile is invalid after calling this!
+void solidity_free() SOLC_NOEXCEPT;
+
 #ifdef __cplusplus
 }
 #endif

test/libsolidity/LibSolc.cpp

@@ -45,6 +45,7 @@ Json::Value compile(string const& _input)
 	string output(solidity_compile(_input.c_str(), nullptr));
 	Json::Value ret;
 	BOOST_REQUIRE(jsonParseStrict(output, ret));
+	solidity_free();
 	return ret;
 }
 
@@ -56,12 +57,14 @@ BOOST_AUTO_TEST_CASE(read_version)
 {
 	string output(solidity_version());
 	BOOST_CHECK(output.find(VersionString) == 0);
+	solidity_free();
 }
 
 BOOST_AUTO_TEST_CASE(read_license)
 {
 	string output(solidity_license());
 	BOOST_CHECK(output.find("GNU GENERAL PUBLIC LICENSE") != string::npos);
+	solidity_free();
 }
 
 BOOST_AUTO_TEST_CASE(standard_compilation)

test/tools/fuzzer_common.cpp

@@ -35,6 +35,10 @@ void FuzzerUtil::runCompiler(string const& _input, bool _quiet)
 	string outputString(solidity_compile(_input.c_str(), nullptr));
 	if (!_quiet)
 		cout << "Output JSON: " << outputString << endl;
+
+	// This should be safe given the above copies the output.
+	solidity_free();
+
 	Json::Value output;
 	if (!jsonParseStrict(outputString, output))
 	{