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fixed MSTORE typo in libevmasm tests #14503

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Sep 18, 2023
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fixed MSTORE typo in libevmasm tests #14503

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4 changes: 2 additions & 2 deletions test/libevmasm/Assembler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -229,8 +229,8 @@ BOOST_AUTO_TEST_CASE(immutables_and_its_source_maps)
auto const NumExpectedMappings =
(
2 + // PUSH <a> PUSH <b>
(numActualRefs - 1) * 5 + // DUP DUP PUSH <n> ADD MTOSRE
3 // PUSH <n> ADD MSTORkhbE
(numActualRefs - 1) * 5 + // DUP DUP PUSH <n> ADD MSTORE
3 // PUSH <n> ADD MSTORE
Comment on lines +232 to +233
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@christianparpart , what are the assumption on the stack before the DUP opcodes? What are we dupping and is <n> supposed to be the immutable value?

this was introduced in:

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Based on the BOOST_AUTO_TEST_CASE(immutable) it seems like on top of the stack we have:

<CODE_OFFSET> <IMMUTABLE_VALUE>

and <n>. represents the relative offset of the immutable position to the code offset.

Perhaps the assumptions about the stack should be documented and wether we are always using DUP2 DUP2.

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snippet from Assembly::assemble():

case AssignImmutable:
{
	// Expect 2 elements on stack (source, dest_base)
	auto const& offsets = immutableReferencesBySub[i.data()].second;
	for (size_t i = 0; i < offsets.size(); ++i)
	{
		if (i != offsets.size() - 1)
		{
			ret.bytecode.push_back(uint8_t(Instruction::DUP2));
			ret.bytecode.push_back(uint8_t(Instruction::DUP2));
		}
		// TODO: should we make use of the constant optimizer methods for pushing the offsets?
		bytes offsetBytes = toCompactBigEndian(u256(offsets[i]));
		ret.bytecode.push_back(static_cast<uint8_t>(pushInstruction(static_cast<unsigned>(offsetBytes.size()))));
		ret.bytecode += offsetBytes;
		ret.bytecode.push_back(uint8_t(Instruction::ADD));
		ret.bytecode.push_back(uint8_t(Instruction::MSTORE));
	}
	if (offsets.empty())
	{
		ret.bytecode.push_back(uint8_t(Instruction::POP));
		ret.bytecode.push_back(uint8_t(Instruction::POP));
	}
	immutableReferencesBySub.erase(i.data());
	break;
}

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Perhaps the assumptions about the stack should be documented and wether we are always using DUP2 DUP2.

Maybe that's a good idea, but then it would be better if done in other PR.

) * numImmutables;

auto constexpr NumSubs = 1;
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