aboutsummaryrefslogtreecommitdiffstats
path: root/libyul/optimiser/FullInliner.h
blob: 495286c099e6cdd855b63d35af6147eb1c2b6a26 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
/*
    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 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, Function Hoister
 * More efficient if run after: Expression Splitter
 */
class FullInliner: public ASTModifier
{
public:
    explicit FullInliner(Block& _ast);

    void run();

    FunctionDefinition& function(std::string _name) { return *m_functions.at(_name); }

private:
    void handleBlock(std::string const& _currentFunctionName, Block& _block);

    /// 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;
    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)
    { }

    virtual void operator()(Block& _block) override;

private:
    boost::optional<std::vector<Statement>> tryInlineStatement(Statement& _statement);
    std::vector<Statement> performInline(Statement& _statement, FunctionCall& _funCall);

    std::string newName(std::string const& _prefix);

    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;
};


}
}