solidity/libyul/optimiser/FullInliner.h
Alex Beregszaszi a22077f736 Rename AsmData -> AST
Also attempt to only include ASTForward where appropriate.
2020-11-25 17:58:02 +00:00

178 lines
5.3 KiB
C++

/*
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/>.
*/
// SPDX-License-Identifier: GPL-3.0
/**
* Optimiser component that performs function inlining for arbitrary functions.
*/
#pragma once
#include <libyul/ASTForward.h>
#include <libyul/optimiser/ASTCopier.h>
#include <libyul/optimiser/ASTWalker.h>
#include <libyul/optimiser/NameDispenser.h>
#include <libyul/optimiser/OptimiserStep.h>
#include <libyul/Exceptions.h>
#include <liblangutil/SourceLocation.h>
#include <optional>
#include <set>
#include <utility>
namespace solidity::yul
{
class NameCollector;
/**
* Optimiser component that modifies an AST in place, inlining functions.
* Expressions are expected to be split, i.e. the component will only inline
* function calls that are at the root of the expression and that only contains
* variables as arguments. More specifically, it will inline
* - let x1, ..., xn := f(a1, ..., am)
* - x1, ..., xn := f(a1, ..., am)
* f(a1, ..., am)
*
* The transform changes code of the form
*
* function f(a, b) -> c { ... }
* let z := f(x, y)
*
* into
*
* function f(a, b) -> c { ... }
*
* let f_a := x
* let f_b := y
* let f_c
* code of f, with replacements: a -> f_a, b -> f_b, c -> f_c
* let z := f_c
*
* Prerequisites: Disambiguator
* More efficient if run after: Function Hoister, Expression Splitter
*/
class FullInliner: public ASTModifier
{
public:
static constexpr char const* name{"FullInliner"};
static void run(OptimiserStepContext& _context, Block& _ast);
/// Inlining heuristic.
/// @param _callSite the name of the function in which the function call is located.
bool shallInline(FunctionCall const& _funCall, YulString _callSite);
FunctionDefinition* function(YulString _name)
{
auto it = m_functions.find(_name);
if (it != m_functions.end())
return it->second;
return nullptr;
}
/// Adds the size of _funCall to the size of _callSite. This is just
/// a rough estimate that is done during inlining. The proper size
/// should be determined after inlining is completed.
void tentativelyUpdateCodeSize(YulString _function, YulString _callSite);
private:
enum Pass { InlineTiny, InlineRest };
FullInliner(Block& _ast, NameDispenser& _dispenser, Dialect const& _dialect);
void run(Pass _pass);
/// @returns a map containing the maximum depths of a call chain starting at each
/// function. For recursive functions, the value is one larger than for all others.
std::map<YulString, size_t> callDepths() const;
void updateCodeSize(FunctionDefinition const& _fun);
void handleBlock(YulString _currentFunctionName, Block& _block);
bool recursive(FunctionDefinition const& _fun) const;
Pass m_pass;
/// The AST to be modified. The root block itself will not be modified, because
/// we store pointers to functions.
Block& m_ast;
std::map<YulString, FunctionDefinition*> m_functions;
/// Functions not to be inlined (because they contain the ``leave`` statement).
std::set<YulString> m_noInlineFunctions;
/// Names of functions to always inline.
std::set<YulString> m_singleUse;
/// Variables that are constants (used for inlining heuristic)
std::set<YulString> m_constants;
std::map<YulString, size_t> m_functionSizes;
NameDispenser& m_nameDispenser;
Dialect const& m_dialect;
};
/**
* 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, YulString _functionName, Dialect const& _dialect):
m_currentFunction(std::move(_functionName)),
m_driver(_driver),
m_nameDispenser(_nameDispenser),
m_dialect(_dialect)
{ }
void operator()(Block& _block) override;
private:
std::optional<std::vector<Statement>> tryInlineStatement(Statement& _statement);
std::vector<Statement> performInline(Statement& _statement, FunctionCall& _funCall);
YulString m_currentFunction;
FullInliner& m_driver;
NameDispenser& m_nameDispenser;
Dialect const& m_dialect;
};
/**
* 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::map<YulString, YulString> _variableReplacements
):
m_nameDispenser(_nameDispenser),
m_variableReplacements(std::move(_variableReplacements))
{}
using ASTCopier::operator ();
Statement operator()(VariableDeclaration const& _varDecl) override;
Statement operator()(FunctionDefinition const& _funDef) override;
YulString translateIdentifier(YulString _name) override;
NameDispenser& m_nameDispenser;
std::map<YulString, YulString> m_variableReplacements;
};
}