fix(codegen): fix legacy ICE when calling getchainparameter

[yanghang8612]

Summary

Calling the TRON getchainparameter builtin aborts the compiler with an internal error on the (default) legacy pipeline.

The bug

GetChainParameter is a bare-call precompile-read, so in appendExternalFunctionCall its encodeInPlace flag starts out true, but it was missing from the list that forces encodeInPlace = false. Its argument is encoded padded, and CompilerUtils::encodeToMemory rejects the in-place + padded combination with a hard assert. As a result, any contract that calls getchainparameter crashes the compiler on the legacy pipeline:

contract C {
    function f() public view returns (uint) {
        return getchainparameter(0);
    }
}

$ solc --bin C.sol
Internal compiler error:
.../libsolidity/codegen/CompilerUtils.cpp(449): ... encodeToMemory(...)
std::exception::what: Non-padded and in-place encoding can only be combined.

via-IR is unaffected (it uses the unified tuple encoder), so this only bites the default pipeline.

The fix

Add GetChainParameter to the encodeInPlace = false list in appendExternalFunctionCall, next to the other precompile-reads. Its argument is then encoded padded (as the precompile expects) and the legacy pipeline compiles it correctly.

Test

Adds cmdlineTests/getchainparameter_legacy, which compiles the contract above on the legacy pipeline with --no-cbor-metadata --bin. Before the fix it ICEs (exit 2); after it produces bytecode.

Targets release_0.8.28.

🤖 Generated with Claude Code

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