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/*
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 <libyul/ASTDataForward.h>
#include <libyul/optimiser/ASTCopier.h>
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/optimiser/NameDispenser.h>
#include <libyul/Exceptions.h>
#include <libevmasm/SourceLocation.h>
#include <boost/variant.hpp>
#include <boost/optional.hpp>
#include <set>
namespace dev
{
namespace yul
{
class NameCollector;
/**
* 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()
{
assertThrow(m_statementsToPrefix.empty(), OptimizerException, "");
}
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;
virtual void visit(Statement& _st) 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);
/// @returns an expression returning nothing.
Expression noop(SourceLocation const& _location);
/// 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;
};
}
}
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