Full inliner.

libjulia/optimiser/FullInliner.cpp

@@ -0,0 +1,237 @@
+/*
+	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/>.
+*/
+/**
+ * Optimiser component that performs function inlining for arbitrary functions.
+ */
+
+#include <libjulia/optimiser/FullInliner.h>
+
+#include <libjulia/optimiser/ASTCopier.h>
+#include <libjulia/optimiser/ASTWalker.h>
+#include <libjulia/optimiser/NameCollector.h>
+
+#include <libsolidity/inlineasm/AsmData.h>
+
+#include <libsolidity/interface/Exceptions.h>
+
+#include <libdevcore/CommonData.h>
+
+#include <boost/range/adaptor/reversed.hpp>
+
+using namespace std;
+using namespace dev;
+using namespace dev::julia;
+using namespace dev::solidity;
+
+
+
+FullInliner::FullInliner(Block& _ast):
+	m_ast(_ast)
+{
+	solAssert(m_ast.statements.size() >= 1, "");
+	m_nameDispenser.m_usedNames = NameCollector(m_ast).names();
+
+	for (size_t i = 1; i < m_ast.statements.size(); ++i)
+	{
+		FunctionDefinition& fun = boost::get<FunctionDefinition>(m_ast.statements.at(i));
+		m_functions[fun.name] = &fun;
+		m_functionsToVisit.insert(&fun);
+	}
+}
+
+void FullInliner::run()
+{
+	solAssert(m_ast.statements[0].type() == typeid(Block), "");
+	InlineModifier(*this, m_nameDispenser, "").visit(m_ast.statements[0]);
+	while (!m_functionsToVisit.empty())
+		handleFunction(**m_functionsToVisit.begin());
+}
+
+void FullInliner::handleFunction(FunctionDefinition& _fun)
+{
+	if (!m_functionsToVisit.count(&_fun))
+		return;
+	m_functionsToVisit.erase(&_fun);
+	(InlineModifier(*this, m_nameDispenser, _fun.name))(_fun.body);
+}
+
+void InlineModifier::operator()(FunctionalInstruction& _instruction)
+{
+	visitArguments(_instruction.arguments);
+}
+
+void InlineModifier::operator()(FunctionCall&)
+{
+	solAssert(false, "Should be handled in visit() instead.");
+}
+
+void InlineModifier::operator()(ForLoop& _loop)
+{
+	(*this)(_loop.pre);
+	// Do not visit the condition because we cannot inline there.
+	(*this)(_loop.post);
+	(*this)(_loop.body);
+}
+
+void InlineModifier::operator()(Block& _block)
+{
+	// TODO: optimize the number of moves here.
+	for (size_t i = 0; i < _block.statements.size(); ++i)
+	{
+		visit(_block.statements.at(i));
+		if (size_t length = m_statementsToPrefix.size())
+		{
+			_block.statements.insert(
+				_block.statements.begin() + i,
+				std::make_move_iterator(m_statementsToPrefix.begin()),
+				std::make_move_iterator(m_statementsToPrefix.end())
+			);
+			i += length;
+			m_statementsToPrefix.clear();
+		}
+	}
+}
+
+void InlineModifier::visit(Expression& _expression)
+{
+	if (_expression.type() != typeid(FunctionCall))
+		return ASTModifier::visit(_expression);
+
+	FunctionCall& funCall = boost::get<FunctionCall>(_expression);
+	FunctionDefinition& fun = m_driver.function(funCall.functionName.name);
+
+	m_driver.handleFunction(fun);
+
+	// TODO: Insert good heuristic here. Perhaps implement that inside the driver.
+	bool doInline = funCall.functionName.name != m_currentFunction;
+
+	if (fun.returnVariables.size() != 1)
+		doInline = false;
+
+	{
+		vector<string> argNames;
+		vector<string> argTypes;
+		for (auto const& arg: fun.parameters)
+		{
+			argNames.push_back(fun.name + "_" + arg.name);
+			argTypes.push_back(arg.type);
+		}
+		visitArguments(funCall.arguments, argNames, argTypes, doInline);
+	}
+
+	if (!doInline)
+		return;
+
+	map<string, string> variableReplacements;
+	string returnVariable = fun.returnVariables[0].name;
+	for (size_t i = 0; i < funCall.arguments.size(); ++i)
+		variableReplacements[fun.parameters[i].name] = boost::get<Identifier>(funCall.arguments[i]).name;
+	variableReplacements[returnVariable] = newName(fun.name + "_" + returnVariable);
+
+	m_statementsToPrefix.emplace_back(VariableDeclaration{
+		funCall.location,
+		{{funCall.location, variableReplacements[returnVariable], fun.returnVariables[0].type}},
+		{}
+	});
+	m_statementsToPrefix.emplace_back(BodyCopier(m_nameDispenser, fun.name + "_", variableReplacements)(fun.body));
+	_expression = Identifier{funCall.location, variableReplacements[returnVariable]};
+}
+
+void InlineModifier::visitArguments(
+	vector<Expression>& _arguments,
+	vector<string> const& _nameHints,
+	vector<string> const& _types,
+	bool _moveToFront
+)
+{
+	// If one of the elements moves parts to the front, all other elements right of it
+	// also have to be moved to the front to keep the order of evaluation.
+	vector<Statement> prefix;
+	for (size_t i = 0; i < _arguments.size(); ++i)
+	{
+		auto& arg = _arguments[i];
+		// TODO optimize vector operations, check that it actually moves
+		auto internalPrefix = visitRecursively(arg);
+		if (!internalPrefix.empty())
+		{
+			_moveToFront = true;
+			// We go through the arguments left to right, so we have to invert
+			// the prefixes.
+			prefix = std::move(internalPrefix) + std::move(prefix);
+		}
+		else if (_moveToFront)
+		{
+			auto location = locationOf(arg);
+			string var = newName(i < _nameHints.size() ? _nameHints[i] : "");
+			prefix.emplace(prefix.begin(), VariableDeclaration{
+				location,
+				{{TypedName{location, var, i < _types.size() ? _types[i] : ""}}},
+				make_shared<Expression>(std::move(arg))
+			});
+			arg = Identifier{location, var};
+		}
+	}
+	m_statementsToPrefix += std::move(prefix);
+}
+
+vector<Statement> InlineModifier::visitRecursively(Expression& _expression)
+{
+	vector<Statement> saved;
+	saved.swap(m_statementsToPrefix);
+	visit(_expression);
+	saved.swap(m_statementsToPrefix);
+	return saved;
+}
+
+string InlineModifier::newName(string const& _prefix)
+{
+	return m_nameDispenser.newName(_prefix);
+}
+
+Statement BodyCopier::operator()(VariableDeclaration const& _varDecl)
+{
+	for (auto const& var: _varDecl.variables)
+		m_variableReplacements[var.name] = m_nameDispenser.newName(m_varNamePrefix + var.name);
+	return ASTCopier::operator()(_varDecl);
+}
+
+Statement BodyCopier::operator()(FunctionDefinition const& _funDef)
+{
+	solAssert(false, "Function hoisting has to be done before function inlining.");
+	return _funDef;
+}
+
+string BodyCopier::translateIdentifier(string const& _name)
+{
+	if (m_variableReplacements.count(_name))
+		return m_variableReplacements.at(_name);
+	else
+		return _name;
+}
+
+string NameDispenser::newName(string const& _prefix)
+{
+	string name = _prefix;
+	size_t suffix = 0;
+	while (name.empty() || m_usedNames.count(name))
+	{
+		suffix++;
+		name = _prefix + "_" + std::to_string(suffix);
+	}
+	m_usedNames.insert(name);
+	return name;
+}

libjulia/optimiser/FullInliner.h

@@ -0,0 +1,180 @@
+/*
+	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/>.
+*/
+/**
+ * Optimiser component that performs function inlining for arbitrary functions.
+ */
+#pragma once
+
+#include <libjulia/ASTDataForward.h>
+
+#include <libjulia/optimiser/ASTCopier.h>
+#include <libjulia/optimiser/ASTWalker.h>
+
+#include <libsolidity/interface/Exceptions.h>
+
+#include <boost/variant.hpp>
+#include <boost/optional.hpp>
+
+#include <set>
+
+namespace dev
+{
+namespace julia
+{
+
+class NameCollector;
+
+struct NameDispenser
+{
+	std::string newName(std::string const& _prefix);
+	std::set<std::string> m_usedNames;
+};
+
+
+
+/**
+ * Optimiser component that modifies an AST in place, inlining arbitrary functions.
+ *
+ * Code of the form
+ *
+ * function f(a, b) -> c { ... }
+ * h(g(x(...), f(arg1(...), arg2(...)), y(...)), z(...))
+ *
+ * is transformed into
+ *
+ * function f(a, b) -> c { ... }
+ *
+ * let z1 := z(...) let y1 := y(...) let a2 := arg2(...) let a1 := arg1(...)
+ * let c1 := 0
+ * { code of f, with replacements: a -> a1, b -> a2, c -> c1, d -> d1 }
+ * h(g(x(...), c1, y1), z1)
+ *
+ * No temporary variable is created for expressions that are "movable"
+ * (i.e. they are "pure", have no side-effects and also do not depend on other code
+ * that might have side-effects).
+ *
+ * This component can only be used on sources with unique names and with hoisted functions,
+ * i.e. the root node has to be a block that itself contains a single block followed by all
+ * function definitions.
+ */
+class FullInliner: public ASTModifier
+{
+public:
+	explicit FullInliner(Block& _ast);
+
+	void run();
+
+	/// Perform inlining operations inside the given function.
+	void handleFunction(FunctionDefinition& _function);
+
+	FunctionDefinition& function(std::string _name) { return *m_functions.at(_name); }
+
+private:
+	/// The AST to be modified. The root block itself will not be modified, because
+	/// we store pointers to functions.
+	Block& m_ast;
+	std::map<std::string, FunctionDefinition*> m_functions;
+	std::set<FunctionDefinition*> m_functionsToVisit;
+	NameDispenser m_nameDispenser;
+};
+
+/**
+ * Class that walks the AST of a block that does not contain function definitions and perform
+ * the actual code modifications.
+ */
+class InlineModifier: public ASTModifier
+{
+public:
+	InlineModifier(FullInliner& _driver, NameDispenser& _nameDispenser, std::string _functionName):
+		m_currentFunction(std::move(_functionName)),
+		m_driver(_driver),
+		m_nameDispenser(_nameDispenser)
+	{ }
+	~InlineModifier()
+	{
+		solAssert(m_statementsToPrefix.empty(), "");
+	}
+
+	virtual void operator()(FunctionalInstruction&) override;
+	virtual void operator()(FunctionCall&) override;
+	virtual void operator()(ForLoop&) override;
+	virtual void operator()(Block& _block) override;
+
+	using ASTModifier::visit;
+	virtual void visit(Expression& _expression) override;
+
+private:
+
+	/// Visits a list of expressions (usually an argument list to a function call) and tries
+	/// to inline them. If one of them is inlined, all right of it have to be moved to the front
+	/// (to keep the order of evaluation). If @a _moveToFront is true, all elements are moved
+	/// to the front. @a _nameHints and @_types are used for the newly created variables, but
+	/// both can be empty.
+	void visitArguments(
+		std::vector<Expression>& _arguments,
+		std::vector<std::string> const& _nameHints = {},
+		std::vector<std::string> const& _types = {},
+		bool _moveToFront = false
+	);
+
+	/// Visits an expression, but saves and restores the current statements to prefix and returns
+	/// the statements that should be prefixed for @a _expression.
+	std::vector<Statement> visitRecursively(Expression& _expression);
+
+	std::string newName(std::string const& _prefix);
+
+	/// List of statements that should go in front of the currently visited AST element,
+	/// at the statement level.
+	std::vector<Statement> m_statementsToPrefix;
+	std::string m_currentFunction;
+	FullInliner& m_driver;
+	NameDispenser& m_nameDispenser;
+};
+
+/**
+ * Creates a copy of a block that is supposed to be the body of a function.
+ * Applies replacements to referenced variables and creates new names for
+ * variable declarations.
+ */
+class BodyCopier: public ASTCopier
+{
+public:
+	BodyCopier(
+		NameDispenser& _nameDispenser,
+		std::string const& _varNamePrefix,
+		std::map<std::string, std::string> const& _variableReplacements
+	):
+		m_nameDispenser(_nameDispenser),
+		m_varNamePrefix(_varNamePrefix),
+		m_variableReplacements(_variableReplacements)
+	{}
+
+	using ASTCopier::operator ();
+
+	virtual Statement operator()(VariableDeclaration const& _varDecl) override;
+	virtual Statement operator()(FunctionDefinition const& _funDef) override;
+
+	virtual std::string translateIdentifier(std::string const& _name) override;
+
+	NameDispenser& m_nameDispenser;
+	std::string const& m_varNamePrefix;
+	std::map<std::string, std::string> m_variableReplacements;
+};
+
+
+}
+}