Full inliner.

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;
+};
+
+
+}
+}