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ethereum / solidity

Solidity, the Smart Contract Programming Language
https://soliditylang.org
GNU General Public License v3.0
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Make source maps byte-offset based instead of opcode-offset #12000

Open chriseth opened 3 years ago

chriseth commented 3 years ago

The source maps currently contain one item per opcode, instead of one item per byte in the assembly. This kind of makes sense because it allows the source maps to be flexible about which push opcode is used for a constant, but it makes it also more difficult because the "pseudo-opcode" AssignImmutable results in multiple opcodes in the end. To make things worse: As soon as one uses verbatim, it is taken as a single opcode by the compiler, but when just seeing the bytecode, it is impossible to tell whether a sequence of opcodes came from a single verbatim or multiple opcodes.

Because of that I would propose to make the source maps byte-based starting from Solidity 0.9.0.

hrkrshnn commented 3 years ago

This sounds good to me. Giving a heads-up to tooling people and perhaps asking for feedback would be nice.

chriseth commented 3 years ago

Maybe we could make it start with a certain string to tell which kind it is and we could also include a version number.

chriseth commented 3 years ago

Decision from design call: We will add a switch (maybe only in stdjson) that defaults to false. If it is true, the source maps will be byte-based and have a string prefix informing about that. The switch will default to true with 0.9.0.