From 6777f7a57fed6b39128773f13084da729dd64588 Mon Sep 17 00:00:00 2001 From: chriseth Date: Thu, 8 Mar 2018 19:41:29 +0100 Subject: Optimize across MLOAD if MSIZE is not used. --- libsolidity/codegen/ExpressionCompiler.cpp | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) (limited to 'libsolidity/codegen/ExpressionCompiler.cpp') diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp index 9e2d30d5..76aa6843 100644 --- a/libsolidity/codegen/ExpressionCompiler.cpp +++ b/libsolidity/codegen/ExpressionCompiler.cpp @@ -850,8 +850,6 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall) } case FunctionType::Kind::ObjectCreation: { - // Will allocate at the end of memory (MSIZE) and not write at all unless the base - // type is dynamically sized. ArrayType const& arrayType = dynamic_cast(*_functionCall.annotation().type); _functionCall.expression().accept(*this); solAssert(arguments.size() == 1, ""); @@ -861,15 +859,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall) utils().convertType(*arguments[0]->annotation().type, IntegerType(256)); // Stack: requested_length - // Allocate at max(MSIZE, freeMemoryPointer) utils().fetchFreeMemoryPointer(); - m_context << Instruction::DUP1 << Instruction::MSIZE; - m_context << Instruction::LT; - auto initialise = m_context.appendConditionalJump(); - // Free memory pointer does not point to empty memory, use MSIZE. - m_context << Instruction::POP; - m_context << Instruction::MSIZE; - m_context << initialise; // Stack: requested_length memptr m_context << Instruction::SWAP1; @@ -894,13 +884,10 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall) // Check if length is zero m_context << Instruction::DUP1 << Instruction::ISZERO; auto skipInit = m_context.appendConditionalJump(); - - // We only have to initialise if the base type is a not a value type. - if (dynamic_cast(arrayType.baseType().get())) - { - m_context << Instruction::DUP2 << u256(32) << Instruction::ADD; - utils().zeroInitialiseMemoryArray(arrayType); - } + // Always initialize because the free memory pointer might point at + // a dirty memory area. + m_context << Instruction::DUP2 << u256(32) << Instruction::ADD; + utils().zeroInitialiseMemoryArray(arrayType); m_context << skipInit; m_context << Instruction::POP; break; -- cgit v1.2.3