solc compiler fun. Collection of some personal patches, mostly as a way to explore various part of the solc codebase.

Compiling

After applying a patch go into the solidity folder and run.

./scripts/build.sh

Implicit casting for user defined types

Solidity doesn't allow you to do the following

type UserType is uint256;

contract Example {
    function cast(uint256 test) internal returns (UserType) {
        return test;
    }
}

It will error with Return argument type uint256 is not implicitly convertible to expected type (type of first return variable) UserType.

However, this seems to just be a limit on the TypeChecker as the IR because if you patch the type checker you can get it to compile just fine.

To bypass just apply the patch and then compile

./generate_implicit_user_type_casting.sh apply

Implicit casting of structs

Similarly to above, the following is not allowed in solc.

struct A {
    address value;
}

struct B {
    address value;
}

contract Example {
    function cast(A memory test) internal returns (B memory) {
        return test;
    }

    function cast(B memory test) internal returns (A memory) {
        return test;
    }
}

To bypass just apply the patch and then compile

./generate_implicit_struct_casting.sh apply

Fixing issue with abi decoder

I have this open issue and was wondering how hard it would be to have some workaround (doesn't need to be a super clean one).

Actually, I can just remove the validator code.

./disable_abicoderv2_validation.sh apply

Adding new yul functions

See the new_yul_functions.diff which adds a jumpdest yul function. This obviously isn't useful for anything special without a jump function also (and also pc) :D, but was done to see how easy / hard it would be to add custom functions to the yul language.

It was surprisingly easy to add a new function.

./generate_new_yul_functions.sh apply

Backporting standard JSON interface

./generate_standard_jsons_diff.sh apply

Will give you the standard JSON for Solc version 0.4.0v (originally introduced in version 0.4.13) with some caveats.

cat ../standard_json_example.json | ./build/solc/solc --standard-json

Disable the full inliner side effects safeguard

(per this old bug)

./disable_full_inliner_side_effects_safeguard.sh apply

./solidity/build/solc/solc --optimize --strict-assembly inliner_test.sol --ir-optimized --bin

Does not match the same behavior as

./solidity/build/solc/solc --yul-optimizations="i" --optimize --strict-assembly inliner_test.sol --ir-optimized --bin

on demand lsp (wip)

./scripts/build.sh  && cat ../lsp_example.json |  build/solc/solc  --lspio 

The idea was to be able to leverage the solc LSP without having to run it as a server. However, I quickly found out that the solc compiler doesn't have the autocomplete support so ended up not completing this.

Content of the lsp_example.json should be a lsp command.

{
	"jsonrpc": "2.0",
	"id": 1,
	"method": "textDocument/didOpen",
	"params": {}
}