diff options
Diffstat (limited to 'libsolidity/codegen/ExpressionCompiler.cpp')
| -rw-r--r-- | libsolidity/codegen/ExpressionCompiler.cpp | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp index 96ca4296..26acd8a4 100644 --- a/libsolidity/codegen/ExpressionCompiler.cpp +++ b/libsolidity/codegen/ExpressionCompiler.cpp @@ -1476,6 +1476,18 @@ void ExpressionCompiler::appendExternalFunctionCall( utils().storeFreeMemoryPointer(); } + // Touch the end of the output area so that we do not pay for memory resize during the call + // (which we would have to subtract from the gas left) + // We could also just use MLOAD; POP right before the gas calculation, but the optimizer + // would remove that, so we use MSTORE here. + if (!_functionType.gasSet() && retSize > 0) + { + m_context << u256(0); + utils().fetchFreeMemoryPointer(); + // This touches too much, but that way we save some rounding arithmetics + m_context << u256(retSize) << Instruction::ADD << Instruction::MSTORE; + } + // Copy function identifier to memory. utils().fetchFreeMemoryPointer(); if (!_functionType.isBareCall() || manualFunctionId) @@ -1551,10 +1563,7 @@ void ExpressionCompiler::appendExternalFunctionCall( gasNeededByCaller += eth::GasCosts::callValueTransferGas; if (!isCallCode && !isDelegateCall && !existenceChecked) gasNeededByCaller += eth::GasCosts::callNewAccountGas; // we never know - m_context << - gasNeededByCaller << - Instruction::GAS << - Instruction::SUB; + m_context << gasNeededByCaller << Instruction::GAS << Instruction::SUB; } if (isDelegateCall) m_context << Instruction::DELEGATECALL; |