Merge pull request #8845 from ethereum/solYulCleanup

[Sol->Yul] Cleanup for checked arithmetic and comparisons.
This commit is contained in:
chriseth 2020-05-05 17:58:36 +02:00 committed by GitHub
commit 4c1e821e01
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9 changed files with 173 additions and 25 deletions

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@ -393,6 +393,8 @@ string YulUtilFunctions::overflowCheckedIntAddFunction(IntegerType const& _type)
return
Whiskers(R"(
function <functionName>(x, y) -> sum {
x := <cleanupFunction>(x)
y := <cleanupFunction>(y)
<?signed>
// overflow, if x >= 0 and y > (maxValue - x)
if and(iszero(slt(x, 0)), sgt(y, sub(<maxValue>, x))) { revert(0, 0) }
@ -409,6 +411,7 @@ string YulUtilFunctions::overflowCheckedIntAddFunction(IntegerType const& _type)
("signed", _type.isSigned())
("maxValue", toCompactHexWithPrefix(u256(_type.maxValue())))
("minValue", toCompactHexWithPrefix(u256(_type.minValue())))
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
@ -421,6 +424,8 @@ string YulUtilFunctions::overflowCheckedIntMulFunction(IntegerType const& _type)
// Multiplication by zero could be treated separately and directly return zero.
Whiskers(R"(
function <functionName>(x, y) -> product {
x := <cleanupFunction>(x)
y := <cleanupFunction>(y)
<?signed>
// overflow, if x > 0, y > 0 and x > (maxValue / y)
if and(and(sgt(x, 0), sgt(y, 0)), gt(x, div(<maxValue>, y))) { revert(0, 0) }
@ -441,6 +446,7 @@ string YulUtilFunctions::overflowCheckedIntMulFunction(IntegerType const& _type)
("signed", _type.isSigned())
("maxValue", toCompactHexWithPrefix(u256(_type.maxValue())))
("minValue", toCompactHexWithPrefix(u256(_type.minValue())))
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
@ -452,6 +458,8 @@ string YulUtilFunctions::overflowCheckedIntDivFunction(IntegerType const& _type)
return
Whiskers(R"(
function <functionName>(x, y) -> r {
x := <cleanupFunction>(x)
y := <cleanupFunction>(y)
if iszero(y) { revert(0, 0) }
<?signed>
// overflow for minVal / -1
@ -466,6 +474,7 @@ string YulUtilFunctions::overflowCheckedIntDivFunction(IntegerType const& _type)
("functionName", functionName)
("signed", _type.isSigned())
("minVal", toCompactHexWithPrefix(u256(_type.minValue())))
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
@ -477,12 +486,15 @@ string YulUtilFunctions::checkedIntModFunction(IntegerType const& _type)
return
Whiskers(R"(
function <functionName>(x, y) -> r {
x := <cleanupFunction>(x)
y := <cleanupFunction>(y)
if iszero(y) { revert(0, 0) }
r := <?signed>s</signed>mod(x, y)
}
)")
("functionName", functionName)
("signed", _type.isSigned())
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
@ -494,6 +506,8 @@ string YulUtilFunctions::overflowCheckedIntSubFunction(IntegerType const& _type)
return
Whiskers(R"(
function <functionName>(x, y) -> diff {
x := <cleanupFunction>(x)
y := <cleanupFunction>(y)
<?signed>
// underflow, if y >= 0 and x < (minValue + y)
if and(iszero(slt(y, 0)), slt(x, add(<minValue>, y))) { revert(0, 0) }
@ -509,6 +523,7 @@ string YulUtilFunctions::overflowCheckedIntSubFunction(IntegerType const& _type)
("signed", _type.isSigned())
("maxValue", toCompactHexWithPrefix(u256(_type.maxValue())))
("minValue", toCompactHexWithPrefix(u256(_type.minValue())))
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
@ -1764,8 +1779,18 @@ string YulUtilFunctions::cleanupFunction(Type const& _type)
solUnimplemented("Fixed point types not implemented.");
break;
case Type::Category::Function:
solAssert(dynamic_cast<FunctionType const&>(_type).kind() == FunctionType::Kind::External, "");
templ("body", "cleaned := " + cleanupFunction(FixedBytesType(24)) + "(value)");
switch (dynamic_cast<FunctionType const&>(_type).kind())
{
case FunctionType::Kind::External:
templ("body", "cleaned := " + cleanupFunction(FixedBytesType(24)) + "(value)");
break;
case FunctionType::Kind::Internal:
templ("body", "cleaned := value");
break;
default:
solAssert(false, "");
break;
}
break;
case Type::Category::Array:
case Type::Category::Struct:
@ -1938,14 +1963,16 @@ std::string YulUtilFunctions::decrementCheckedFunction(Type const& _type)
return Whiskers(R"(
function <functionName>(value) -> ret {
value := <cleanupFunction>(value)
if <lt>(value, <minval>) { revert(0,0) }
ret := sub(value, 1)
}
)")
("functionName", functionName)
("minval", toCompactHexWithPrefix(minintval))
("lt", type.isSigned() ? "slt" : "lt")
.render();
("functionName", functionName)
("minval", toCompactHexWithPrefix(minintval))
("lt", type.isSigned() ? "slt" : "lt")
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
@ -1966,14 +1993,16 @@ std::string YulUtilFunctions::incrementCheckedFunction(Type const& _type)
return Whiskers(R"(
function <functionName>(value) -> ret {
value := <cleanupFunction>(value)
if <gt>(value, <maxval>) { revert(0,0) }
ret := add(value, 1)
}
)")
("functionName", functionName)
("maxval", toCompactHexWithPrefix(maxintval))
("gt", type.isSigned() ? "sgt" : "gt")
.render();
("functionName", functionName)
("maxval", toCompactHexWithPrefix(maxintval))
("gt", type.isSigned() ? "sgt" : "gt")
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
@ -1988,15 +2017,17 @@ string YulUtilFunctions::negateNumberCheckedFunction(Type const& _type)
return m_functionCollector.createFunction(functionName, [&]() {
return Whiskers(R"(
function <functionName>(_value) -> ret {
if slt(_value, <minval>) { revert(0,0) }
ret := sub(0, _value)
function <functionName>(value) -> ret {
value := <cleanupFunction>(value)
if slt(value, <minval>) { revert(0,0) }
ret := sub(0, value)
}
)")
("functionName", functionName)
("minval", toCompactHexWithPrefix(minintval))
.render();
});
("functionName", functionName)
("minval", toCompactHexWithPrefix(minintval))
("cleanupFunction", cleanupFunction(_type))
.render();
});
}
string YulUtilFunctions::zeroValueFunction(Type const& _type, bool _splitFunctionTypes)

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@ -496,9 +496,9 @@ bool IRGeneratorForStatements::visit(BinaryOperation const& _binOp)
isSigned = type->isSigned();
string args =
expressionAsType(_binOp.leftExpression(), *commonType) +
expressionAsType(_binOp.leftExpression(), *commonType, true) +
", " +
expressionAsType(_binOp.rightExpression(), *commonType);
expressionAsType(_binOp.rightExpression(), *commonType, true);
string expr;
if (op == Token::Equal)
@ -1811,11 +1811,16 @@ IRVariable IRGeneratorForStatements::convert(IRVariable const& _from, Type const
}
}
std::string IRGeneratorForStatements::expressionAsType(Expression const& _expression, Type const& _to)
std::string IRGeneratorForStatements::expressionAsType(Expression const& _expression, Type const& _to, bool _forceCleanup)
{
IRVariable from(_expression);
if (from.type() == _to)
return from.commaSeparatedList();
{
if (_forceCleanup)
return m_utils.cleanupFunction(_to) + "(" + from.commaSeparatedList() + ")";
else
return from.commaSeparatedList();
}
else
return m_utils.conversionFunction(from.type(), _to) + "(" + from.commaSeparatedList() + ")";
}

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@ -112,7 +112,8 @@ private:
/// @returns a Yul expression representing the current value of @a _expression,
/// converted to type @a _to if it does not yet have that type.
std::string expressionAsType(Expression const& _expression, Type const& _to);
/// If @a _forceCleanup is set to true, it also cleans the value, in case it already has type @a _to.
std::string expressionAsType(Expression const& _expression, Type const& _to, bool _forceCleanup = false);
/// @returns an output stream that can be used to define @a _var using a function call or
/// single stack slot expression.

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@ -325,6 +325,7 @@ Parser::ElementaryOperation Parser::parseElementaryOperation()
case Token::Bool:
case Token::Address:
case Token::Var:
case Token::In:
{
YulString literal{currentLiteral()};
if (m_dialect.builtin(literal))
@ -515,6 +516,7 @@ YulString Parser::expectAsmIdentifier()
case Token::Bool:
case Token::Identifier:
case Token::Var:
case Token::In:
break;
default:
expectToken(Token::Identifier);

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@ -30,7 +30,8 @@ contract C {
return arr[i](x);
}
}
// ====
// compileViaYul: also
// ----
// test(uint256,uint256): 10, 0 -> 11
// test(uint256,uint256): 10, 1 -> 12

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@ -10,6 +10,7 @@ contract C {
require(y == bytes2(0xffff));
}
}
// ====
// compileViaYul: also
// ----
// f() -> "\xff\xff\xff\xff"

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@ -22,7 +22,8 @@ contract C {
return garbled != garbled;
}
}
// ====
// compileViaYul: also
// ----
// test_eq_ok() -> 1
// test_eq() -> FAILURE # both should throw #

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@ -0,0 +1,65 @@
contract C {
function add() public pure returns (uint8, uint8) {
uint8 x; uint8 y = 0;
assembly { x := 0x0101 }
return (x + y, y + x);
}
function sub() public pure returns (uint8, uint8) {
uint8 x; uint8 y = 1;
assembly { x := 0x0101 }
return (x - y, y - x);
}
function mul() public pure returns (uint8, uint8) {
uint8 x; uint8 y = 1;
assembly { x := 0x0101 }
return (x * y, y * x);
}
function div() public pure returns (uint8, uint8) {
uint8 x; uint8 y = 1;
assembly { x := 0x0101 }
return (x / y, y / x);
}
function mod() public pure returns (uint8, uint8) {
uint8 x; uint8 y = 2;
assembly { x := 0x0101 }
return (x % y, y % x);
}
function inc_pre() public pure returns (uint8) {
uint8 x;
assembly { x := 0x0100 }
return ++x;
}
function inc_post() public pure returns (uint8) {
uint8 x;
assembly { x := 0x0100 }
return x++;
}
function dec_pre() public pure returns (uint8) {
uint8 x;
assembly { x := not(0xFF) }
return --x;
}
function dec_post() public pure returns (uint8) {
uint8 x;
assembly { x := not(0xFF) }
return x--;
}
function neg() public pure returns (int8) {
int8 x;
assembly { x := 0x80 }
return -x;
}
}
// ====
// compileViaYul: true
// ----
// add() -> 1, 1
// sub() -> 0, 0
// mul() -> 1, 1
// div() -> 1, 1
// mod() -> 1, 0
// inc_pre() -> 1
// inc_post() -> 0
// dec_pre() -> FAILURE
// dec_post() -> FAILURE
// neg() -> FAILURE

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@ -0,0 +1,41 @@
contract C {
function eq() public pure returns (bool) {
uint8 x = 1; uint8 y;
assembly { y := 0x0101 }
return (x == y);
}
function neq() public pure returns (bool) {
uint8 x = 1; uint8 y;
assembly { y := 0x0101 }
return (x != y);
}
function geq() public pure returns (bool) {
uint8 x = 1; uint8 y;
assembly { y := 0x0101 }
return (x >= y);
}
function leq() public pure returns (bool) {
uint8 x = 2; uint8 y;
assembly { y := 0x0101 }
return (x <= y);
}
function gt() public pure returns (bool) {
uint8 x = 2; uint8 y;
assembly { y := 0x0101 }
return (x > y);
}
function lt() public pure returns (bool) {
uint8 x = 1; uint8 y;
assembly { y := 0x0101 }
return (x < y);
}
}
// ====
// compileViaYul: also
// ----
// eq() -> true
// neq() -> false
// geq() -> true
// leq() -> false
// gt() -> true
// lt() -> false