Emscripten 4.0.12 introduced breaking change by changing module factory
to always return promise even if `WASM_ASYNC_COMPILATION=0`. To overcome this, build emscripten compiler without MODULARIZE with custom export of `createRevive`.
As a drive-by fix, the get-llvm action now ignores LLVM releases marked
as pre-release.
---------
Signed-off-by: xermicus <bigcyrill@hotmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
# Description
Compilation times for resolc were significantly slower than solc when:
* Multiple files were included in the JSON input file via
`--standard-json`
* And none of the files requested code generation
* (If only a subset of files requested code generation, both resolc and
solc were very slow)
Reason:
* Resolc unconditionally generated bytecode for all contracts, even if
not requested.
* When compiling to PolkaVM bytecode, we need to pass additional flags
(e.g. `irOptimized`) to solc. If these flags were not explicitly
requested, resolc also added these to the requested output since PolkaVM
bytecode was always generated.
## Breaking Changes
The following changes are breaking, but fix the semantics to match its
intended behavior:
* Compiling with `--standard-json` now compiles to PolkaVM bytecode
***only*** for the contracts explicitly requested in the
`outputSelection`.
* Compiling with `--standard-json` now outputs ***only*** the explicitly
requested output (e.g. `evm.assembly`, `evm.bytecode`, `ast`, etc.).
```jsonc
// Example:
{
"settings": {
// ...
"outputSelection": {
"src/common/GasService.sol": {
// Contracts in this file will generate bytecode.
// Only these fields of the JSON output selection will be in the `contracts` output.
"*": ["abi", "evm.methodIdentifiers", "metadata", "evm.bytecode"],
// Only this field of the JSON output selection will be in the `sources` output.
"": ["ast"]
},
"src/common/Gateway.sol": {
// No contracts in this file will generate bytecode.
"*": ["abi", "evm.methodIdentifiers", "metadata"],
// No `ast` will be in the `sources` output (only the automatically added `id`,
// similar to solc as this is not a configurable output selection).
"": []
},
}
}
}
```
## Performance Improvements
When e.g. the standard JSON input file includes multiple files and
requests output for every contract as per this setting:
```jsonc
{
"settings": {
// ...
"optimizer": { "enabled": true, "runs": 1 },
"viaIR": true,
"outputSelection": {
"src/common/GasService.sol": {
"*": ["abi", "evm.methodIdentifiers", "metadata", "evm.bytecode"],
},
// Rest of files..
}
}
}
```
The differences in compilation times depending on whether `evm.bytecode`
is selected in every file, one file, or no files can be seen below:
| Solc Optimizer (runs=1) | ViaIR | Request `abi`,
`evm.methodIdentifiers`, `metadata` | Request `evm.bytecode` | resolc
before | resolc after | solc v0.8.33 |
|:-----------------------:|:-----:|:---------:|:---------:|:-------------:|:------------:|:----------:|
| ✅ | ✅ | All files | All files | `~14.5s` | `~14.5s` | `~13.5s` |
| ✅ | ✅ | All files | One file | `~14.5s` | `~450ms` | `~13.5s` |
| ✅ | ✅ | All files | No files | `~14.5s` | `~390ms` | `~350ms` |
**Observations:**
* `resolc before` is roughly the same no matter the request
* This is due to unconditionally generating bytecode
* When not requesting bytecode for any contracts:
* `resolc after` now compiles in ~390ms (vs ~14.5s), similar to `solc`
* Neither `solc` nor `resolc after` generates bytecode when none of the
contracts request it
* When requesting bytecode for all contracts in _only one_ file:
* `resolc after` now compiles in ~450ms (vs ~14.5s)
* `solc` still compiles in the same time as when requesting bytecode for
all contracts in all files
* This is something they have tried to improve (see
[Solidity#15373](https://github.com/argotorg/solidity/issues/15373) and
[Solidity#15615](https://github.com/argotorg/solidity/issues/15615)),
and the intended behavior seems to now be that bytecode should only be
generated when explicitly requested for each contract.
* Even though PRs have merged to try to fix it, their issue seems to
persist as of v0.8.33.
# Open Questions
* Foundry:
* [x] Pruning of the AST:
* Just saw [this past
commit](https://github.com/paritytech/revive/pull/385) to not prune the
AST for Foundry compatibility.
* Can Foundry not explicitly request `"": "ast"`?
* **Answer:**
* Pruning the AST when not requested should be fine, as long as Foundry
explicitly requests it when needed.
* Will be tested by Foundry maintainer.
# Review Notes
Changes in `docs/` (~25 files) can be skipped as they are automatically
updated after adding content to `book/` and rebuilding it.
# Resolved Issues
Closes#326
---------
Co-authored-by: xermicus <cyrill@parity.io>
- Add support for solc `v0.8.30`. No changes in YUL or the binary
interface.
- Fix a semver bug in the NPM packages to correctly align their solc
dependencies with our last supported version.
---------
Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>
kvpanch