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Use conditional Whiskers.

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This commit is contained in:
chriseth 2019-05-07 15:12:21 +02:00
parent 9e09b5d33b
commit c6b9fa96ae
1 changed files with 71 additions and 90 deletions
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161
libsolidity/codegen/YulUtilFunctions.cpp
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@ -260,35 +260,25 @@ string YulUtilFunctions::shiftRightFunction(size_t _numBits)
// Note that if this is extended with signed shifts,
// the opcodes SAR and SDIV behave differently with regards to rounding!
string functionName = "shift_right_" + to_string(_numBits) + "_unsigned";
if (m_evmVersion.hasBitwiseShifting())
{
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> newValue {
newValue := shr(<numBits>, value)
}
)")
("functionName", functionName)
("numBits", to_string(_numBits))
.render();
});
}
else
{
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> newValue {
newValue := div(value, <multiplier>)
}
)")
("functionName", functionName)
("multiplier", toCompactHexWithPrefix(u256(1) << _numBits))
.render();
});
}
string functionName = "shift_right_" + to_string(_numBits) + "_unsigned_" + m_evmVersion.name();
return m_functionCollector->createFunction(functionName, [&]() {
return
Whiskers(R"(
function <functionName>(value) -> newValue {
newValue :=
<?hasShifts>
shr(<numBits>, value)
<!hasShifts>
div(value, <multiplier>)
</hasShifts>
}
)")
("functionName", functionName)
("hasShifts", m_evmVersion.hasBitwiseShifting())
("numBits", to_string(_numBits))
("multiplier", toCompactHexWithPrefix(u256(1) << _numBits))
.render();
});
}
string YulUtilFunctions::updateByteSliceFunction(size_t _numBytes, size_t _shiftBytes)
@ -335,28 +325,23 @@ string YulUtilFunctions::overflowCheckedUIntAddFunction(size_t _bits)
solAssert(0 < _bits && _bits <= 256 && _bits % 8 == 0, "");
string functionName = "checked_add_uint_" + to_string(_bits);
return m_functionCollector->createFunction(functionName, [&]() {
if (_bits < 256)
return
Whiskers(R"(
function <functionName>(x, y) -> sum {
return
Whiskers(R"(
function <functionName>(x, y) -> sum {
<?shortType>
let mask := <mask>
sum := add(and(x, mask), and(y, mask))
if and(sum, not(mask)) { revert(0, 0) }
}
)")
("functionName", functionName)
("mask", toCompactHexWithPrefix((u256(1) << _bits) - 1))
.render();
else
return
Whiskers(R"(
function <functionName>(x, y) -> sum {
<!shortType>
sum := add(x, y)
if lt(sum, x) { revert(0, 0) }
}
)")
("functionName", functionName)
.render();
</shortType>
}
)")
("shortType", _bits < 256)
("functionName", functionName)
("mask", toCompactHexWithPrefix((u256(1) << _bits) - 1))
.render();
});
}
@ -366,43 +351,38 @@ string YulUtilFunctions::arrayLengthFunction(ArrayType const& _type)
return m_functionCollector->createFunction(functionName, [&]() {
Whiskers w(R"(
function <functionName>(value) -> length {
<body>
<?dynamic>
<?memory>
length := mload(value)
</memory>
<?storage>
length := sload(value)
<?byteArray>
// Retrieve length both for in-place strings and off-place strings:
// Computes (x & (0x100 * (ISZERO (x & 1)) - 1)) / 2
// i.e. for short strings (x & 1 == 0) it does (x & 0xff) / 2 and for long strings it
// computes (x & (-1)) / 2, which is equivalent to just x / 2.
let mask := sub(mul(0x100, iszero(and(length, 1))), 1)
length := div(and(length, mask), 2)
</byteArray>
</storage>
<!dynamic>
length := <length>
</dynamic>
}
)");
w("functionName", functionName);
string body;
w("dynamic", _type.isDynamicallySized());
if (!_type.isDynamicallySized())
body = "length := " + toCompactHexWithPrefix(_type.length());
else
{
switch (_type.location())
{
case DataLocation::CallData:
solAssert(false, "called regular array length function on calldata array");
break;
case DataLocation::Memory:
body = "length := mload(value)";
break;
case DataLocation::Storage:
if (_type.isByteArray())
{
// Retrieve length both for in-place strings and off-place strings:
// Computes (x & (0x100 * (ISZERO (x & 1)) - 1)) / 2
// i.e. for short strings (x & 1 == 0) it does (x & 0xff) / 2 and for long strings it
// computes (x & (-1)) / 2, which is equivalent to just x / 2.
body = R"(
length := sload(value)
let mask := sub(mul(0x100, iszero(and(length, 1))), 1)
length := div(and(length, mask), 2)
)";
}
else
body = "length := sload(value)";
break;
}
}
solAssert(!body.empty(), "");
w("body", body);
w("length", toCompactHexWithPrefix(_type.length()));
w("memory", _type.location() == DataLocation::Memory);
w("storage", _type.location() == DataLocation::Storage);
w("byteArray", _type.isByteArray());
if (_type.isDynamicallySized())
solAssert(
_type.location() != DataLocation::CallData,
"called regular array length function on calldata array"
);
return w.render();
});
}
@ -416,20 +396,21 @@ string YulUtilFunctions::arrayAllocationSizeFunction(ArrayType const& _type)
function <functionName>(length) -> size {
// Make sure we can allocate memory without overflow
if gt(length, 0xffffffffffffffff) { revert(0, 0) }
size := <allocationSize>
<addLengthSlot>
<?byteArray>
// round up
size := and(add(length, 0x1f), not(0x1f))
<!byteArray>
size := mul(length, 0x20)
</byteArray>
<?dynamic>
// add length slot
size := add(size, 0x20)
</dynamic>
}
)");
w("functionName", functionName);
if (_type.isByteArray())
// Round up
w("allocationSize", "and(add(length, 0x1f), not(0x1f))");
else
w("allocationSize", "mul(length, 0x20)");
if (_type.isDynamicallySized())
w("addLengthSlot", "size := add(size, 0x20)");
else
w("addLengthSlot", "");
w("byteArray", _type.isByteArray());
w("dynamic", _type.isDynamicallySized());
return w.render();
});
}