aboutsummaryrefslogtreecommitdiffstats
path: root/libsolidity/codegen/LValue.cpp
blob: 6d71d36f9eb4a64258dcdd02ff8f237bf4ee49a6 (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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
/*
    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/>.
*/
/**
 * @author Christian <c@ethdev.com>
 * @date 2015
 * LValues for use in the expression compiler.
 */

#include <libsolidity/codegen/LValue.h>
#include <libevmasm/Instruction.h>
#include <libsolidity/ast/Types.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/codegen/CompilerUtils.h>

using namespace std;
using namespace dev;
using namespace langutil;
using namespace solidity;


StackVariable::StackVariable(CompilerContext& _compilerContext, VariableDeclaration const& _declaration):
    LValue(_compilerContext, _declaration.annotation().type.get()),
    m_baseStackOffset(m_context.baseStackOffsetOfVariable(_declaration)),
    m_size(m_dataType->sizeOnStack())
{
}

void StackVariable::retrieveValue(SourceLocation const& _location, bool) const
{
    unsigned stackPos = m_context.baseToCurrentStackOffset(m_baseStackOffset);
    if (stackPos + 1 > 16) //@todo correct this by fetching earlier or moving to memory
        BOOST_THROW_EXCEPTION(
            CompilerError() <<
            errinfo_sourceLocation(_location) <<
            errinfo_comment("Stack too deep, try removing local variables.")
        );
    solAssert(stackPos + 1 >= m_size, "Size and stack pos mismatch.");
    for (unsigned i = 0; i < m_size; ++i)
        m_context << dupInstruction(stackPos + 1);
}

void StackVariable::storeValue(Type const&, SourceLocation const& _location, bool _move) const
{
    unsigned stackDiff = m_context.baseToCurrentStackOffset(m_baseStackOffset) - m_size + 1;
    if (stackDiff > 16)
        BOOST_THROW_EXCEPTION(
            CompilerError() <<
            errinfo_sourceLocation(_location) <<
            errinfo_comment("Stack too deep, try removing local variables.")
        );
    else if (stackDiff > 0)
        for (unsigned i = 0; i < m_size; ++i)
            m_context << swapInstruction(stackDiff) << Instruction::POP;
    if (!_move)
        retrieveValue(_location);
}

void StackVariable::setToZero(SourceLocation const& _location, bool) const
{
    CompilerUtils(m_context).pushZeroValue(*m_dataType);
    storeValue(*m_dataType, _location, true);
}

MemoryItem::MemoryItem(CompilerContext& _compilerContext, Type const& _type, bool _padded):
    LValue(_compilerContext, &_type),
    m_padded(_padded)
{
}

void MemoryItem::retrieveValue(SourceLocation const&, bool _remove) const
{
    if (m_dataType->isValueType())
    {
        if (!_remove)
            m_context << Instruction::DUP1;
        CompilerUtils(m_context).loadFromMemoryDynamic(*m_dataType, false, m_padded, false);
    }
    else
        m_context << Instruction::MLOAD;
}

void MemoryItem::storeValue(Type const& _sourceType, SourceLocation const&, bool _move) const
{
    CompilerUtils utils(m_context);
    if (m_dataType->isValueType())
    {
        solAssert(_sourceType.isValueType(), "");
        utils.moveIntoStack(_sourceType.sizeOnStack());
        utils.convertType(_sourceType, *m_dataType, true);
        if (!_move)
        {
            utils.moveToStackTop(m_dataType->sizeOnStack());
            utils.copyToStackTop(1 + m_dataType->sizeOnStack(), m_dataType->sizeOnStack());
        }
        if (!m_padded)
        {
            solAssert(m_dataType->calldataEncodedSize(false) == 1, "Invalid non-padded type.");
            if (m_dataType->category() == Type::Category::FixedBytes)
                m_context << u256(0) << Instruction::BYTE;
            m_context << Instruction::SWAP1 << Instruction::MSTORE8;
        }
        else
        {
            utils.storeInMemoryDynamic(*m_dataType, m_padded);
            m_context << Instruction::POP;
        }
    }
    else
    {
        solUnimplementedAssert(_sourceType == *m_dataType, "Conversion not implemented for assignment to memory.");

        solAssert(m_dataType->sizeOnStack() == 1, "");
        if (!_move)
            m_context << Instruction::DUP2 << Instruction::SWAP1;
        // stack: [value] value lvalue
        // only store the reference
        m_context << Instruction::MSTORE;
    }
}

void MemoryItem::setToZero(SourceLocation const&, bool _removeReference) const
{
    CompilerUtils utils(m_context);
    solAssert(_removeReference, "");
    utils.pushZeroValue(*m_dataType);
    utils.storeInMemoryDynamic(*m_dataType, m_padded);
    m_context << Instruction::POP;
}

StorageItem::StorageItem(CompilerContext& _compilerContext, VariableDeclaration const& _declaration):
    StorageItem(_compilerContext, *_declaration.annotation().type)
{
    auto const& location = m_context.storageLocationOfVariable(_declaration);
    m_context << location.first << u256(location.second);
}

StorageItem::StorageItem(CompilerContext& _compilerContext, Type const& _type):
    LValue(_compilerContext, &_type)
{
    if (m_dataType->isValueType())
    {
        if (m_dataType->category() != Type::Category::Function)
            solAssert(m_dataType->storageSize() == m_dataType->sizeOnStack(), "");
        solAssert(m_dataType->storageSize() == 1, "Invalid storage size.");
    }
}

void StorageItem::retrieveValue(SourceLocation const&, bool _remove) const
{
    // stack: storage_key storage_offset
    if (!m_dataType->isValueType())
    {
        solAssert(m_dataType->sizeOnStack() == 1, "Invalid storage ref size.");
        if (_remove)
            m_context << Instruction::POP; // remove byte offset
        else
            m_context << Instruction::DUP2;
        return;
    }
    if (!_remove)
        CompilerUtils(m_context).copyToStackTop(sizeOnStack(), sizeOnStack());
    if (m_dataType->storageBytes() == 32)
        m_context << Instruction::POP << Instruction::SLOAD;
    else
    {
        bool cleaned = false;
        m_context
            << Instruction::SWAP1 << Instruction::SLOAD << Instruction::SWAP1
            << u256(0x100) << Instruction::EXP << Instruction::SWAP1 << Instruction::DIV;
        if (m_dataType->category() == Type::Category::FixedPoint)
            // implementation should be very similar to the integer case.
            solUnimplemented("Not yet implemented - FixedPointType.");
        if (m_dataType->category() == Type::Category::FixedBytes)
        {
            CompilerUtils(m_context).leftShiftNumberOnStack(256 - 8 * m_dataType->storageBytes());
            cleaned = true;
        }
        else if (
            m_dataType->category() == Type::Category::Integer &&
            dynamic_cast<IntegerType const&>(*m_dataType).isSigned()
        )
        {
            m_context << u256(m_dataType->storageBytes() - 1) << Instruction::SIGNEXTEND;
            cleaned = true;
        }
        else if (FunctionType const* fun = dynamic_cast<decltype(fun)>(m_dataType))
        {
            if (fun->kind() == FunctionType::Kind::External)
            {
                CompilerUtils(m_context).splitExternalFunctionType(false);
                cleaned = true;
            }
        }
        if (!cleaned)
        {
            solAssert(m_dataType->sizeOnStack() == 1, "");
            m_context << ((u256(0x1) << (8 * m_dataType->storageBytes())) - 1) << Instruction::AND;
        }
    }
}

void StorageItem::storeValue(Type const& _sourceType, SourceLocation const& _location, bool _move) const
{
    CompilerUtils utils(m_context);
    solAssert(m_dataType, "");

    // stack: value storage_key storage_offset
    if (m_dataType->isValueType())
    {
        solAssert(m_dataType->storageBytes() <= 32, "Invalid storage bytes size.");
        solAssert(m_dataType->storageBytes() > 0, "Invalid storage bytes size.");
        if (m_dataType->storageBytes() == 32)
        {
            solAssert(m_dataType->sizeOnStack() == 1, "Invalid stack size.");
            // offset should be zero
            m_context << Instruction::POP;
            if (!_move)
                m_context << Instruction::DUP2 << Instruction::SWAP1;

            m_context << Instruction::SWAP1;
            utils.convertType(_sourceType, *m_dataType, true);
            m_context << Instruction::SWAP1;

            m_context << Instruction::SSTORE;
        }
        else
        {
            // OR the value into the other values in the storage slot
            m_context << u256(0x100) << Instruction::EXP;
            // stack: value storage_ref multiplier
            // fetch old value
            m_context << Instruction::DUP2 << Instruction::SLOAD;
            // stack: value storege_ref multiplier old_full_value
            // clear bytes in old value
            m_context
                << Instruction::DUP2 << ((u256(1) << (8 * m_dataType->storageBytes())) - 1)
                << Instruction::MUL;
            m_context << Instruction::NOT << Instruction::AND << Instruction::SWAP1;
            // stack: value storage_ref cleared_value multiplier
            utils.copyToStackTop(3 + m_dataType->sizeOnStack(), m_dataType->sizeOnStack());
            // stack: value storage_ref cleared_value multiplier value
            if (FunctionType const* fun = dynamic_cast<decltype(fun)>(m_dataType))
            {
                solAssert(_sourceType == *m_dataType, "function item stored but target is not equal to source");
                if (fun->kind() == FunctionType::Kind::External)
                    // Combine the two-item function type into a single stack slot.
                    utils.combineExternalFunctionType(false);
                else
                    m_context <<
                        ((u256(1) << (8 * m_dataType->storageBytes())) - 1) <<
                        Instruction::AND;
            }
            else if (m_dataType->category() == Type::Category::FixedBytes)
            {
                solAssert(_sourceType.category() == Type::Category::FixedBytes, "source not fixed bytes");
                CompilerUtils(m_context).rightShiftNumberOnStack(256 - 8 * dynamic_cast<FixedBytesType const&>(*m_dataType).numBytes());
            }
            else
            {
                solAssert(m_dataType->sizeOnStack() == 1, "Invalid stack size for opaque type.");
                // remove the higher order bits
                utils.convertType(_sourceType, *m_dataType, true, true);
            }
            m_context  << Instruction::MUL << Instruction::OR;
            // stack: value storage_ref updated_value
            m_context << Instruction::SWAP1 << Instruction::SSTORE;
            if (_move)
                utils.popStackElement(*m_dataType);
        }
    }
    else
    {
        solAssert(
            _sourceType.category() == m_dataType->category(),
            "Wrong type conversation for assignment.");
        if (m_dataType->category() == Type::Category::Array)
        {
            m_context << Instruction::POP; // remove byte offset
            ArrayUtils(m_context).copyArrayToStorage(
                dynamic_cast<ArrayType const&>(*m_dataType),
                dynamic_cast<ArrayType const&>(_sourceType)
            );
            if (_move)
                m_context << Instruction::POP;
        }
        else if (m_dataType->category() == Type::Category::Struct)
        {
            // stack layout: source_ref target_ref target_offset
            // note that we have structs, so offset should be zero and are ignored
            m_context << Instruction::POP;
            auto const& structType = dynamic_cast<StructType const&>(*m_dataType);
            auto const& sourceType = dynamic_cast<StructType const&>(_sourceType);
            solAssert(
                structType.structDefinition() == sourceType.structDefinition(),
                "Struct assignment with conversion."
            );
            solAssert(sourceType.location() != DataLocation::CallData, "Structs in calldata not supported.");
            for (auto const& member: structType.members(nullptr))
            {
                // assign each member that is not a mapping
                TypePointer const& memberType = member.type;
                if (memberType->category() == Type::Category::Mapping)
                    continue;
                TypePointer sourceMemberType = sourceType.memberType(member.name);
                if (sourceType.location() == DataLocation::Storage)
                {
                    // stack layout: source_ref target_ref
                    pair<u256, unsigned> const& offsets = sourceType.storageOffsetsOfMember(member.name);
                    m_context << offsets.first << Instruction::DUP3 << Instruction::ADD;
                    m_context << u256(offsets.second);
                    // stack: source_ref target_ref source_member_ref source_member_off
                    StorageItem(m_context, *sourceMemberType).retrieveValue(_location, true);
                    // stack: source_ref target_ref source_value...
                }
                else
                {
                    solAssert(sourceType.location() == DataLocation::Memory, "");
                    // stack layout: source_ref target_ref
                    TypePointer sourceMemberType = sourceType.memberType(member.name);
                    m_context << sourceType.memoryOffsetOfMember(member.name);
                    m_context << Instruction::DUP3 << Instruction::ADD;
                    MemoryItem(m_context, *sourceMemberType).retrieveValue(_location, true);
                    // stack layout: source_ref target_ref source_value...
                }
                unsigned stackSize = sourceMemberType->sizeOnStack();
                pair<u256, unsigned> const& offsets = structType.storageOffsetsOfMember(member.name);
                m_context << dupInstruction(1 + stackSize) << offsets.first << Instruction::ADD;
                m_context << u256(offsets.second);
                // stack: source_ref target_ref target_off source_value... target_member_ref target_member_byte_off
                StorageItem(m_context, *memberType).storeValue(*sourceMemberType, _location, true);
            }
            // stack layout: source_ref target_ref
            solAssert(sourceType.sizeOnStack() == 1, "Unexpected source size.");
            if (_move)
                utils.popStackSlots(2);
            else
                m_context << Instruction::SWAP1 << Instruction::POP;
        }
        else
            BOOST_THROW_EXCEPTION(
                InternalCompilerError()
                    << errinfo_sourceLocation(_location)
                    << errinfo_comment("Invalid non-value type for assignment."));
    }
}

void StorageItem::setToZero(SourceLocation const&, bool _removeReference) const
{
    if (m_dataType->category() == Type::Category::Array)
    {
        if (!_removeReference)
            CompilerUtils(m_context).copyToStackTop(sizeOnStack(), sizeOnStack());
        ArrayUtils(m_context).clearArray(dynamic_cast<ArrayType const&>(*m_dataType));
    }
    else if (m_dataType->category() == Type::Category::Struct)
    {
        // stack layout: storage_key storage_offset
        // @todo this can be improved: use StorageItem for non-value types, and just store 0 in
        // all slots that contain value types later.
        auto const& structType = dynamic_cast<StructType const&>(*m_dataType);
        for (auto const& member: structType.members(nullptr))
        {
            // zero each member that is not a mapping
            TypePointer const& memberType = member.type;
            if (memberType->category() == Type::Category::Mapping)
                continue;
            pair<u256, unsigned> const& offsets = structType.storageOffsetsOfMember(member.name);
            m_context
                << offsets.first << Instruction::DUP3 << Instruction::ADD
                << u256(offsets.second);
            StorageItem(m_context, *memberType).setToZero();
        }
        if (_removeReference)
            m_context << Instruction::POP << Instruction::POP;
    }
    else
    {
        solAssert(m_dataType->isValueType(), "Clearing of unsupported type requested: " + m_dataType->toString());
        if (!_removeReference)
            CompilerUtils(m_context).copyToStackTop(sizeOnStack(), sizeOnStack());
        if (m_dataType->storageBytes() == 32)
        {
            // offset should be zero
            m_context
                << Instruction::POP << u256(0)
                << Instruction::SWAP1 << Instruction::SSTORE;
        }
        else
        {
            m_context << u256(0x100) << Instruction::EXP;
            // stack: storage_ref multiplier
            // fetch old value
            m_context << Instruction::DUP2 << Instruction::SLOAD;
            // stack: storege_ref multiplier old_full_value
            // clear bytes in old value
            m_context
                << Instruction::SWAP1 << ((u256(1) << (8 * m_dataType->storageBytes())) - 1)
                << Instruction::MUL;
            m_context << Instruction::NOT << Instruction::AND;
            // stack: storage_ref cleared_value
            m_context << Instruction::SWAP1 << Instruction::SSTORE;
        }
    }
}

/// Used in StorageByteArrayElement
static FixedBytesType byteType(1);

StorageByteArrayElement::StorageByteArrayElement(CompilerContext& _compilerContext):
    LValue(_compilerContext, &byteType)
{
}

void StorageByteArrayElement::retrieveValue(SourceLocation const&, bool _remove) const
{
    // stack: ref byte_number
    if (_remove)
        m_context << Instruction::SWAP1 << Instruction::SLOAD
            << Instruction::SWAP1 << Instruction::BYTE;
    else
        m_context << Instruction::DUP2 << Instruction::SLOAD
            << Instruction::DUP2 << Instruction::BYTE;
    m_context << (u256(1) << (256 - 8)) << Instruction::MUL;
}

void StorageByteArrayElement::storeValue(Type const&, SourceLocation const&, bool _move) const
{
    // stack: value ref byte_number
    m_context << u256(31) << Instruction::SUB << u256(0x100) << Instruction::EXP;
    // stack: value ref (1<<(8*(31-byte_number)))
    m_context << Instruction::DUP2 << Instruction::SLOAD;
    // stack: value ref (1<<(8*(31-byte_number))) old_full_value
    // clear byte in old value
    m_context << Instruction::DUP2 << u256(0xff) << Instruction::MUL
        << Instruction::NOT << Instruction::AND;
    // stack: value ref (1<<(32-byte_number)) old_full_value_with_cleared_byte
    m_context << Instruction::SWAP1;
    m_context << (u256(1) << (256 - 8)) << Instruction::DUP5 << Instruction::DIV
        << Instruction::MUL << Instruction::OR;
    // stack: value ref new_full_value
    m_context << Instruction::SWAP1 << Instruction::SSTORE;
    if (_move)
        m_context << Instruction::POP;
}

void StorageByteArrayElement::setToZero(SourceLocation const&, bool _removeReference) const
{
    // stack: ref byte_number
    solAssert(_removeReference, "");
    m_context << u256(31) << Instruction::SUB << u256(0x100) << Instruction::EXP;
    // stack: ref (1<<(8*(31-byte_number)))
    m_context << Instruction::DUP2 << Instruction::SLOAD;
    // stack: ref (1<<(8*(31-byte_number))) old_full_value
    // clear byte in old value
    m_context << Instruction::SWAP1 << u256(0xff) << Instruction::MUL;
    m_context << Instruction::NOT << Instruction::AND;
    // stack: ref old_full_value_with_cleared_byte
    m_context << Instruction::SWAP1 << Instruction::SSTORE;
}

StorageArrayLength::StorageArrayLength(CompilerContext& _compilerContext, const ArrayType& _arrayType):
    LValue(_compilerContext, _arrayType.memberType("length").get()),
    m_arrayType(_arrayType)
{
    solAssert(m_arrayType.isDynamicallySized(), "");
}

void StorageArrayLength::retrieveValue(SourceLocation const&, bool _remove) const
{
    ArrayUtils(m_context).retrieveLength(m_arrayType);
    if (_remove)
        m_context << Instruction::SWAP1 << Instruction::POP;
}

void StorageArrayLength::storeValue(Type const&, SourceLocation const&, bool _move) const
{
    if (_move)
        m_context << Instruction::SWAP1;
    else
        m_context << Instruction::DUP2;
    ArrayUtils(m_context).resizeDynamicArray(m_arrayType);
}

void StorageArrayLength::setToZero(SourceLocation const&, bool _removeReference) const
{
    solAssert(_removeReference, "");
    ArrayUtils(m_context).clearDynamicArray(m_arrayType);
}


TupleObject::TupleObject(
    CompilerContext& _compilerContext,
    std::vector<std::unique_ptr<LValue>>&& _lvalues
):
    LValue(_compilerContext), m_lvalues(move(_lvalues))
{
}

unsigned TupleObject::sizeOnStack() const
{
    unsigned size = 0;
    for (auto const& lv: m_lvalues)
        if (lv)
            size += lv->sizeOnStack();
    return size;
}

void TupleObject::retrieveValue(SourceLocation const&, bool) const
{
    solAssert(false, "Tried to retrieve value of tuple.");
}

void TupleObject::storeValue(Type const& _sourceType, SourceLocation const& _location, bool) const
{
    // values are below the lvalue references
    unsigned valuePos = sizeOnStack();
    TypePointers const& valueTypes = dynamic_cast<TupleType const&>(_sourceType).components();
    solAssert(valueTypes.size() == m_lvalues.size(), "");
    // valuePos .... refPos ...
    // We will assign from right to left to optimize stack layout.
    for (size_t i = 0; i < m_lvalues.size(); ++i)
    {
        unique_ptr<LValue> const& lvalue = m_lvalues[m_lvalues.size() - i - 1];
        TypePointer const& valType = valueTypes[valueTypes.size() - i - 1];
        unsigned stackHeight = m_context.stackHeight();
        solAssert(!valType == !lvalue, "");
        if (!lvalue)
            continue;
        valuePos += valType->sizeOnStack();
        // copy value to top
        CompilerUtils(m_context).copyToStackTop(valuePos, valType->sizeOnStack());
        // move lvalue ref above value
        CompilerUtils(m_context).moveToStackTop(valType->sizeOnStack(), lvalue->sizeOnStack());
        lvalue->storeValue(*valType, _location, true);
        valuePos += m_context.stackHeight() - stackHeight;
    }
    // As the type of an assignment to a tuple type is the empty tuple, we always move.
    CompilerUtils(m_context).popStackElement(_sourceType);
}

void TupleObject::setToZero(SourceLocation const&, bool) const
{
    solAssert(false, "Tried to delete tuple.");
}