[yul-phaser] Make Program and Population classes accept source code rather than file path

- I need some sample .yul files for testing but I see that existing tests generally have source code hard-coded in them rather than in standalone .yul files. There are lots of .yul files but they seem to be automatically processed by a special test case rather loaded ad-hoc by manually created tests.
- Program and Population required a file name until now. I'm making them accept loaded source code to be able to give them data hard-coded in a test.

tools/yulPhaser/Population.cpp

@@ -26,6 +26,7 @@
 
 using namespace std;
 using namespace solidity;
+using namespace solidity::langutil;
 using namespace solidity::phaser;
 
 namespace solidity::phaser
@@ -48,25 +49,25 @@ ostream& phaser::operator<<(ostream& _stream, Individual const& _individual)
 	return _stream;
 }
 
-Population::Population(string const& _sourcePath, vector<Chromosome> const& _chromosomes):
-	m_sourcePath{_sourcePath}
+Population::Population(CharStream _sourceCode, vector<Chromosome> const& _chromosomes):
+	m_sourceCode{move(_sourceCode)}
 {
 	for (auto const& chromosome: _chromosomes)
 		m_individuals.push_back({chromosome});
 }
 
-Population Population::makeRandom(string const& _sourcePath, size_t _size)
+Population Population::makeRandom(CharStream _sourceCode, size_t _size)
 {
 	vector<Individual> individuals;
 	for (size_t i = 0; i < _size; ++i)
 		individuals.push_back({Chromosome::makeRandom(randomChromosomeLength())});
 
-	return Population(_sourcePath, individuals);
+	return Population(move(_sourceCode), individuals);
 }
 
-size_t Population::measureFitness(Chromosome const& _chromosome, string const& _sourcePath)
+size_t Population::measureFitness(Chromosome const& _chromosome, CharStream& _sourceCode)
 {
-	auto program = Program::load(_sourcePath);
+	auto program = Program::load(_sourceCode);
 	program.optimise(_chromosome.optimisationSteps());
 	return program.codeSize();
 }
@@ -87,7 +88,7 @@ void Population::run(optional<size_t> _numRounds, ostream& _outputStream)
 
 ostream& phaser::operator<<(ostream& _stream, Population const& _population)
 {
-	_stream << "Source: " << _population.m_sourcePath << endl;
+	_stream << "Stream name: " << _population.m_sourceCode.name() << endl;
 
 	auto individual = _population.m_individuals.begin();
 	for (; individual != _population.m_individuals.end(); ++individual)
@@ -105,7 +106,7 @@ void Population::doEvaluation()
 {
 	for (auto& individual: m_individuals)
 		if (!individual.fitness.has_value())
-			individual.fitness = measureFitness(individual.chromosome, m_sourcePath);
+			individual.fitness = measureFitness(individual.chromosome, m_sourceCode);
 }
 
 void Population::doSelection()

tools/yulPhaser/Population.h

@@ -20,6 +20,8 @@
 #include <tools/yulPhaser/Chromosome.h>
 #include <tools/yulPhaser/Random.h>
 
+#include <liblangutil/CharStream.h>
+
 #include <optional>
 #include <ostream>
 #include <vector>
@@ -53,21 +55,21 @@ class Population
 public:
 	static constexpr size_t MaxChromosomeLength = 30;
 
-	explicit Population(std::string const& _sourcePath, std::vector<Chromosome> const& _chromosomes = {});
-	static Population makeRandom(std::string const& _sourcePath, size_t _size);
+	explicit Population(langutil::CharStream _sourceCode, std::vector<Chromosome> const& _chromosomes = {});
+	static Population makeRandom(langutil::CharStream _sourceCode, size_t _size);
 
 	void run(std::optional<size_t> _numRounds, std::ostream& _outputStream);
 
 	std::vector<Individual> const& individuals() const { return m_individuals; }
 
 	static size_t randomChromosomeLength() { return binomialRandomInt(MaxChromosomeLength, 0.5); }
-	static size_t measureFitness(Chromosome const& _chromosome, std::string const& _sourcePath);
+	static size_t measureFitness(Chromosome const& _chromosome, langutil::CharStream& _sourceCode);
 
 	friend std::ostream& operator<<(std::ostream& _stream, Population const& _population);
 
 private:
-	explicit Population(std::string const& _sourcePath, std::vector<Individual> _individuals = {}):
-		m_sourcePath{_sourcePath},
+	explicit Population(langutil::CharStream _sourceCode, std::vector<Individual> _individuals = {}):
+		m_sourceCode{std::move(_sourceCode)},
 		m_individuals{std::move(_individuals)} {}
 
 	void doMutation();
@@ -79,7 +81,7 @@ private:
 		size_t _count
 	);
 
-	std::string m_sourcePath;
+	langutil::CharStream m_sourceCode;
 
 	std::vector<Individual> m_individuals;
 };

tools/yulPhaser/Program.cpp

@@ -38,11 +38,8 @@
 #include <libyul/optimiser/OptimiserStep.h>
 #include <libyul/optimiser/Suite.h>
 
-#include <libsolutil/CommonIO.h>
 #include <libsolutil/JSON.h>
 
-#include <boost/filesystem.hpp>
-
 #include <cassert>
 #include <memory>
 
@@ -60,10 +57,11 @@ ostream& operator<<(ostream& _stream, Program const& _program);
 
 }
 
-Program Program::load(string const& _sourcePath)
+Program Program::load(CharStream& _sourceCode)
 {
+	// ASSUMPTION: parseSource() rewinds the stream on its own
 	Dialect const& dialect = EVMDialect::strictAssemblyForEVMObjects(EVMVersion{});
-	unique_ptr<Block> ast = parseSource(dialect, loadSource(_sourcePath));
+	unique_ptr<Block> ast = parseSource(dialect, _sourceCode);
 	unique_ptr<AsmAnalysisInfo> analysisInfo = analyzeAST(dialect, *ast);
 
 	Program program(
@@ -95,14 +93,6 @@ string Program::toJson() const
 	return jsonPrettyPrint(serializedAst);
 }
 
-CharStream Program::loadSource(string const& _sourcePath)
-{
-	assertThrow(boost::filesystem::exists(_sourcePath), InvalidProgram, "Source file does not exist");
-
-	string sourceCode = readFileAsString(_sourcePath);
-	return CharStream(sourceCode, _sourcePath);
-}
-
 unique_ptr<Block> Program::parseSource(Dialect const& _dialect, CharStream _source)
 {
 	ErrorList errors;

tools/yulPhaser/Program.h

@@ -65,7 +65,7 @@ public:
 	{}
 	Program operator=(Program&& program) = delete;
 
-	static Program load(std::string const& _sourcePath);
+	static Program load(langutil::CharStream& _sourceCode);
 	void optimise(std::vector<std::string> const& _optimisationSteps);
 
 	size_t codeSize() const { return computeCodeSize(*m_ast); }
@@ -84,7 +84,6 @@ private:
 		m_nameDispenser(_dialect, *m_ast, {})
 	{}
 
-	static langutil::CharStream loadSource(std::string const& _sourcePath);
 	static std::unique_ptr<yul::Block> parseSource(
 		yul::Dialect const& _dialect,
 		langutil::CharStream _source

tools/yulPhaser/main.cpp

@@ -18,13 +18,20 @@
 #include <tools/yulPhaser/Exceptions.h>
 #include <tools/yulPhaser/Population.h>
 
+#include <libsolutil/Assertions.h>
+#include <libsolutil/CommonIO.h>
+#include <liblangutil/CharStream.h>
+
+#include <boost/filesystem.hpp>
 #include <boost/program_options.hpp>
 
 #include <iostream>
 #include <string>
 
 using namespace std;
+using namespace solidity::langutil;
 using namespace solidity::phaser;
+using namespace solidity::util;
 
 namespace po = boost::program_options;
 
@@ -37,9 +44,17 @@ struct CommandLineParsingResult
 	po::variables_map arguments;
 };
 
+CharStream loadSource(string const& _sourcePath)
+{
+	assertThrow(boost::filesystem::exists(_sourcePath), InvalidProgram, "Source file does not exist");
+
+	string sourceCode = readFileAsString(_sourcePath);
+	return CharStream(sourceCode, _sourcePath);
+}
+
 void runAlgorithm(string const& _sourcePath)
 {
-	auto population = Population::makeRandom(_sourcePath, 10);
+	auto population = Population::makeRandom(loadSource(_sourcePath), 10);
 	population.run(nullopt, cout);
 }