WebAssembly / WebAssembly/binaryen
Regression on optimized module size depending on final markers
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- Dominant language
- WebAssembly
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Description
The commit https://github.com/WebAssembly/binaryen/commit/7df30640820c9b4acfc69ffc7616809a727d1241 introduced a severe size regression for fs.wasm.gz when optimized with
wasm-opt -all --closed-world -tnh -O3 --type-ssa --gufa -O3 --type-merging -O1
Before the change, it optimized to 1520024 bytes. After, it optimizes to 1890468 bytes.
The module declares all struct types as non-final. If it instead marks all types final that don't have any subtypes (ff.wasm.gz), the change introduces a smaller regression from 1540124 to 1639628 bytes.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the regression with fs.wasm.gz and ff.wasm.gz using the wasm-opt command in the issue, then compare the behavior before and after commit 7df30640820c9b4acfc69ffc7616809a727d124. Trace the optimization change affecting final markers; done means the optimized module sizes no longer show the reported regression for these cases.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp, wasm
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 32/100