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Skip extcodesize check if return data is expected.

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This commit is contained in:
chriseth
2021-11-08 14:58:09 +01:00
parent ea3c34a082
commit a1aa9d2d90
35 changed files with 270 additions and 67 deletions
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libsolidity/codegen/ExpressionCompiler.cpp
+15 -3
View File
@@ -2630,9 +2630,21 @@ void ExpressionCompiler::appendExternalFunctionCall(
// Check the target contract exists (has code) for non-low-level calls.
if (funKind == FunctionType::Kind::External || funKind == FunctionType::Kind::DelegateCall)
{
m_context << Instruction::DUP1 << Instruction::EXTCODESIZE << Instruction::ISZERO;
m_context.appendConditionalRevert(false, "Target contract does not contain code");
existenceChecked = true;
size_t encodedHeadSize = 0;
for (auto const& t: returnTypes)
encodedHeadSize += t->decodingType()->calldataHeadSize();
// We do not need to check extcodesize if we expect return data, since if there is no
// code, the call will return empty data and the ABI decoder will revert.
if (
encodedHeadSize == 0 ||
!haveReturndatacopy ||
m_context.revertStrings() >= RevertStrings::Debug
)
{
m_context << Instruction::DUP1 << Instruction::EXTCODESIZE << Instruction::ISZERO;
m_context.appendConditionalRevert(false, "Target contract does not contain code");
existenceChecked = true;
}
}
if (_functionType.gasSet())
libsolidity/codegen/ir/IRGeneratorForStatements.cpp
+18 -2
View File
@@ -2451,8 +2451,10 @@ void IRGeneratorForStatements::appendExternalFunctionCall(
appendCode() << "mstore(add(" << m_utils.allocateUnboundedFunction() << "() , " << to_string(returnInfo.estimatedReturnSize) << "), 0)\n";
}
Whiskers templ(R"(if iszero(extcodesize(<address>)) { <revertNoCode>() }
Whiskers templ(R"(
<?checkExtcodesize>
if iszero(extcodesize(<address>)) { <revertNoCode>() }
</checkExtcodesize>
// storage for arguments and returned data
let <pos> := <allocateUnbounded>()
mstore(<pos>, <shl28>(<funSel>))
@@ -2477,6 +2479,18 @@ void IRGeneratorForStatements::appendExternalFunctionCall(
}
)");
templ("revertNoCode", m_utils.revertReasonIfDebugFunction("Target contract does not contain code"));
// We do not need to check extcodesize if we expect return data: If there is no
// code, the call will return empty data and the ABI decoder will revert.
size_t encodedHeadSize = 0;
for (auto const& t: returnInfo.returnTypes)
encodedHeadSize += t->decodingType()->calldataHeadSize();
bool const checkExtcodesize =
encodedHeadSize == 0 ||
!m_context.evmVersion().supportsReturndata() ||
m_context.revertStrings() >= RevertStrings::Debug;
templ("checkExtcodesize", checkExtcodesize);
templ("pos", m_context.newYulVariable());
templ("end", m_context.newYulVariable());
if (_functionCall.annotation().tryCall)
@@ -2532,6 +2546,8 @@ void IRGeneratorForStatements::appendExternalFunctionCall(
u256 gasNeededByCaller = evmasm::GasCosts::callGas(m_context.evmVersion()) + 10;
if (funType.valueSet())
gasNeededByCaller += evmasm::GasCosts::callValueTransferGas;
if (!checkExtcodesize)
gasNeededByCaller += evmasm::GasCosts::callNewAccountGas; // we never know
templ("gas", "sub(gas(), " + formatNumber(gasNeededByCaller) + ")");
}
// Order is important here, STATICCALL might overlap with DELEGATECALL.