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Improves assembly and adds more tests.

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This commit is contained in:
Erik Kundt
2018-05-30 17:40:33 +02:00
parent 7156a01acc
commit 34b5eca1f8
5 changed files with 139 additions and 35 deletions
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libsolidity/codegen/ArrayUtils.cpp
+12 -20
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@@ -837,29 +837,23 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
switch and(slot_value, 1)
case 0 {
// short byte array
let length := and(div(slot_value, 2), 0x3f)
let length := and(div(slot_value, 2), 0x1f)
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)
// Zero-out the suffix inlcluding the least significant byte.
let mask := sub(exp(0x100, sub(33, length)), 1)
length := sub(length, 1)
slot_value := or(and(not(mask), slot_value), mul(length, 2))
sstore(ref, slot_value)
}
case 1 {
// long byte array
let length := div(slot_value, 2)
let slot := keccak256(0, 0x20)
mstore(0, ref)
switch length
case 32
{
let slot := keccak256(0, 0x20)
let data := sload(slot)
sstore(slot, 0)
data := and(data, not(0xff))
@@ -867,14 +861,14 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
}
default
{
let slot := div(sub(length, 1), 32)
let offset := and(sub(length, 1), 0x1f)
slot := add(keccak256(0, 0x20), slot)
let slot_offset := div(sub(length, 1), 32)
let length_offset := and(sub(length, 1), 0x1f)
slot := add(slot, slot_offset)
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)
let mask := sub(exp(0x100, sub(32, length_offset)), 1)
data := and(not(mask), data)
sstore(slot, data)
@@ -887,8 +881,7 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
m_context << Instruction::POP;
}
else
{
{
// stack: ArrayReference
retrieveLength(_type);
// stack: ArrayReference oldLength
@@ -897,7 +890,6 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
m_context << Instruction::ISZERO;
m_context.appendConditionalInvalid();
// Stack: ArrayReference oldLength
m_context << u256(1) << Instruction::SWAP1 << Instruction::SUB;
// Stack ArrayReference newLength
@@ -905,7 +897,7 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
// Stack ArrayReference newLength ArrayReference newLength;
accessIndex(_type, false);
// Stack: ArrayReference newLength storage_slot byte_offset
StorageItem(m_context, _type).setToZero(SourceLocation(), true);
StorageItem(m_context, *_type.baseType()).setToZero(SourceLocation(), true);
// Stack: ArrayReference newLength
m_context << Instruction::SWAP1 << Instruction::SSTORE;
}