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
|
/*
This file is part of cpp-ethereum.
cpp-ethereum 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.
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2014
* Solidity AST to EVM bytecode compiler for expressions.
*/
#include <boost/noncopyable.hpp>
#include <libdevcore/Common.h>
#include <libsolidity/ASTVisitor.h>
namespace dev {
namespace eth
{
class AssemblyItem; // forward
}
namespace solidity {
class CompilerContext; // forward
class Type; // forward
class IntegerType; // forward
/**
* Compiler for expressions, i.e. converts an AST tree whose root is an Expression into a stream
* of EVM instructions. It needs a compiler context that is the same for the whole compilation
* unit.
*/
class ExpressionCompiler: private ASTVisitor
{
public:
/// Compile the given @a _expression into the @a _context.
static void compileExpression(CompilerContext& _context, Expression const& _expression);
/// Appends code to remove dirty higher order bits in case of an implicit promotion to a wider type.
static void appendTypeConversion(CompilerContext& _context, Type const& _typeOnStack, Type const& _targetType);
private:
ExpressionCompiler(CompilerContext& _compilerContext):
m_context(_compilerContext), m_currentLValue(m_context) {}
virtual bool visit(Assignment const& _assignment) override;
virtual void endVisit(UnaryOperation const& _unaryOperation) override;
virtual bool visit(BinaryOperation const& _binaryOperation) override;
virtual bool visit(FunctionCall const& _functionCall) override;
virtual void endVisit(MemberAccess const& _memberAccess) override;
virtual bool visit(IndexAccess const& _indexAccess) override;
virtual void endVisit(Identifier const& _identifier) override;
virtual void endVisit(Literal const& _literal) override;
///@{
///@name Append code for various operator types
void appendAndOrOperatorCode(BinaryOperation const& _binaryOperation);
void appendCompareOperatorCode(Token::Value _operator, Type const& _type);
void appendOrdinaryBinaryOperatorCode(Token::Value _operator, Type const& _type);
void appendArithmeticOperatorCode(Token::Value _operator, Type const& _type);
void appendBitOperatorCode(Token::Value _operator);
void appendShiftOperatorCode(Token::Value _operator);
/// @}
/// Appends an implicit or explicit type conversion. For now this comprises only erasing
/// higher-order bits (@see appendHighBitCleanup) when widening integer types.
/// If @a _cleanupNeeded, high order bits cleanup is also done if no type conversion would be
/// necessary.
void appendTypeConversion(Type const& _typeOnStack, Type const& _targetType, bool _cleanupNeeded = false);
//// Appends code that cleans higher-order bits for integer types.
void appendHighBitsCleanup(IntegerType const& _typeOnStack);
/**
* Helper class to store and retrieve lvalues to and from various locations.
* All types except STACK store a reference in a slot on the stack, STACK just
* stores the base stack offset of the variable in @a m_baseStackOffset.
*/
class LValue
{
public:
enum LValueType { NONE, STACK, MEMORY, STORAGE };
explicit LValue(CompilerContext& _compilerContext): m_context(&_compilerContext) { reset(); }
LValue(CompilerContext& _compilerContext, LValueType _type, unsigned _baseStackOffset = 0):
m_context(&_compilerContext), m_type(_type), m_baseStackOffset(_baseStackOffset) {}
/// Set type according to the declaration and retrieve the reference.
/// @a _expression is the current expression
void fromIdentifier(Identifier const& _identifier, Declaration const& _declaration);
void reset() { m_type = NONE; m_baseStackOffset = 0; }
bool isValid() const { return m_type != NONE; }
bool isInOnStack() const { return m_type == STACK; }
bool isInMemory() const { return m_type == MEMORY; }
bool isInStorage() const { return m_type == STORAGE; }
/// @returns true if this lvalue reference type occupies a slot on the stack.
bool storesReferenceOnStack() const { return m_type == STORAGE || m_type == MEMORY; }
/// Copies the value of the current lvalue to the top of the stack and, if @a _remove is true,
/// also removes the reference from the stack (note that is does not reset the type to @a NONE).
/// @a _expression is the current expression, used for error reporting.
void retrieveValue(Expression const& _expression, bool _remove = false) const;
/// Stores a value (from the stack directly beneath the reference, which is assumed to
/// be on the top of the stack, if any) in the lvalue and removes the reference.
/// Also removes the stored value from the stack if @a _move is
/// true. @a _expression is the current expression, used for error reporting.
void storeValue(Expression const& _expression, bool _move = false) const;
/// Convenience function to convert the stored reference to a value and reset type to NONE if
/// the reference was not requested by @a _expression.
void retrieveValueIfLValueNotRequested(Expression const& _expression);
private:
CompilerContext* m_context;
LValueType m_type;
/// If m_type is STACK, this is base stack offset (@see
/// CompilerContext::getBaseStackOffsetOfVariable) of a local variable.
unsigned m_baseStackOffset;
};
CompilerContext& m_context;
LValue m_currentLValue;
/// If a "virtual" function (i.e. a bulit-in function without jump tag) is encountered, the
/// actual function is stored here. @todo prevent assignment or store it with assignment
enum class SpecialFunction { NONE, SEND, SHA3, SUICIDE, ECRECOVER, SHA256, RIPEMD160 };
SpecialFunction m_currentSpecialFunction;
};
}
}
|
