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Implements pop() for byte arrays.

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This commit is contained in:
Erik Kundt
2018-05-29 12:53:02 +02:00
parent e9dcfb0b62
commit 7156a01acc
2 changed files with 146 additions and 16 deletions
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libsolidity/codegen/ArrayUtils.cpp
+65 -10
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@@ -830,19 +830,74 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
if (!_type.isByteArray() && _type.baseType()->storageBytes() < 32)
solAssert(_type.baseType()->isValueType(), "Invalid storage size for non-value type.");
// stack: ArrayReference
retrieveLength(_type);
// stack: ArrayReference oldLength
m_context << Instruction::DUP1;
// stack: ArrayReference oldLength oldLength
m_context << Instruction::ISZERO;
m_context.appendConditionalInvalid();
if (_type.isByteArray())
{
m_context.appendInlineAssembly(R"({
let slot_value := sload(ref)
switch and(slot_value, 1)
case 0 {
// short byte array
let length := and(div(slot_value, 2), 0x3f)
if iszero(length) { invalid() }
// Zero-out the suffix of the byte array by masking it.
// Do not zero-out the least significant byte, but mask the
// higher bits of the length.
// (((1<<(8 * (32 - length))) - 1) << 8) + 128
let mask := add(mul(0x100, sub(exp(0x100, sub(32, length)), 1)), 0x80)
slot_value := and(not(mask), slot_value)
// Reduce the length by 1
slot_value := sub(slot_value, 2)
sstore(ref, slot_value)
}
case 1 {
// long byte array
let length := div(slot_value, 2)
mstore(0, ref)
switch length
case 32
{
let slot := keccak256(0, 0x20)
let data := sload(slot)
sstore(slot, 0)
data := and(data, not(0xff))
sstore(ref, or(data, 62))
}
default
{
let slot := div(sub(length, 1), 32)
let offset := and(sub(length, 1), 0x1f)
slot := add(keccak256(0, 0x20), slot)
let data := sload(slot)
// Zero-out the suffix of the byte array by masking it.
// ((1<<(8 * (32 - offset))) - 1)
let mask := sub(exp(0x100, sub(32, offset)), 1)
data := and(not(mask), data)
sstore(slot, data)
// Reduce the length by 1
slot_value := sub(slot_value, 2)
sstore(ref, slot_value)
}
}
})", {"ref"});
m_context << Instruction::POP;
}
else
{
{
// stack: ArrayReference
retrieveLength(_type);
// stack: ArrayReference oldLength
m_context << Instruction::DUP1;
// stack: ArrayReference oldLength oldLength
m_context << Instruction::ISZERO;
m_context.appendConditionalInvalid();
// Stack: ArrayReference oldLength
m_context << u256(1) << Instruction::SWAP1 << Instruction::SUB;
// Stack ArrayReference newLength
@@ -852,7 +907,7 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
// Stack: ArrayReference newLength storage_slot byte_offset
StorageItem(m_context, _type).setToZero(SourceLocation(), true);
// Stack: ArrayReference newLength
m_context << Instruction::SSTORE;
m_context << Instruction::SWAP1 << Instruction::SSTORE;
}
}