WebAssembly/binaryen

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Optimizer and compiler/toolchain library for WebAssembly

Stars: 8.6k
Forks: 885
Open beginner issues: 0
Indexed issues: 332
Avg merge: 1d 19h
Merged PRs (30d): 69

Dominant language: WebAssembly
License: Apache-2.0
Last GitHub push: Sep 19, 2026
Latest indexed: Sep 20, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted

Beginner friendly Everything

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332 open issues indexed

Lower WASM exceptions to MVP (or maybe GC) Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#7179 · 4 comments · Opened Dec 24, 2024
Escaping issues in json.h Open

Difficulty 3/5 1-2 days Newbie friendliness 25/100

WebAssembly/binaryen#7176 · Opened Dec 20, 2024
Binaryen's Emscripten bindings do not support WASM_BIGINT Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#7163 · Opened Dec 19, 2024
wasm2js aborts when allocating pages. Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#7126 · 12 comments · 2 reactions · Opened Nov 28, 2024
Missed opportunity to merge private types into public supertypes Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#7120 · Opened Nov 26, 2024
emited text contains tuple instructions even when using --intrinsic-lowering Open

Difficulty 4/5 3-5 days Newbie friendliness 28/100

WebAssembly/binaryen#7028 · 10 comments · Opened Oct 23, 2024
Asyncify does not support unwinding from functions returning non-nullable values Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

WebAssembly/binaryen#6990 · 3 comments · 1 reaction · Opened Oct 7, 2024
Flatten does not handle `BrOn`. Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6989 · 3 comments · Opened Oct 7, 2024
Relaxing closed world validation and improving open world optimization Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6965 · 7 comments · Opened Sep 23, 2024
Improving Precompute performance Open

interpreter

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6931 · 4 comments · Opened Sep 11, 2024
`select` not optimized when condition is true and ifFalse arm isn't pure Open

Difficulty 3/5 1-2 days Newbie friendliness 38/100

WebAssembly/binaryen#6930 · 3 comments · Opened Sep 11, 2024
SIGSEGV (Address boundary error) in dumpDebugLoc(llvm::DWARFContext&, llvm::DWARFYAML::Data&) () Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

WebAssembly/binaryen#6879 · 1 comment · Opened Aug 28, 2024
wasm-as/wasm-dis seem to miscompile ref.null with type-index heap type Open

WebAssembly/binaryen#6860 · 8 comments · 1 assignee · Opened Aug 21, 2024
Support cross-module calls properly in the interpreter Open

interpreter

Difficulty 5/5 Over a week Newbie friendliness 35/100

WebAssembly/binaryen#6823 · 2 comments · Opened Aug 7, 2024
Are there plans for Rust bindings? Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6788 · 6 comments · Opened Jul 25, 2024
Start publishing signature files for binaryen artifacts Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6783 · 9 comments · Opened Jul 23, 2024
support to add custom sections at the beginning of module Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

WebAssembly/binaryen#6775 · Opened Jul 19, 2024
Add support for Wasm components in wasm-opt Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

WebAssembly/binaryen#6728 · 15 comments · 14 reactions · Opened Jul 11, 2024
Missing optimization in Wasm for `x < 0 || x > constant` Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6685 · 3 comments · 1 reaction · Opened Jun 19, 2024
Adding unsubtyping to O3 Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

WebAssembly/binaryen#6622 · 1 reaction · Opened May 21, 2024
Improvements enabled by new wat parser Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

WebAssembly/binaryen#6617 · 2 comments · Opened May 20, 2024
Support branch hinting Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6616 · 2 reactions · Opened May 20, 2024
Support custom section annotations Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6615 · Opened May 20, 2024
Use ChildTyper in the validator Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6613 · 9 comments · Opened May 20, 2024
Import and run the upstream spec tests Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6612 · 1 reaction · Opened May 20, 2024
Run (basic) StackIR optimizations in all binary writes? Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6509 · 4 comments · Opened Apr 17, 2024
How to traverse memory segments and get their data? Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6491 · Opened Apr 11, 2024
Asyncify: warn/error when functions match both ADD and REMOVE Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6482 · Opened Apr 10, 2024
Output structured data format based on wasm-delegations.def Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

WebAssembly/binaryen#6460 · 1 comment · Opened Apr 1, 2024
Emitting unreachable for unemittable String instructions can fail due to blocks Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6443 · 2 comments · Opened Mar 26, 2024
Impossible address ranges in DWARF debug info Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6406 · 1 comment · Opened Mar 16, 2024
wasm-opt: "compile unit size was incorrect" Open

Difficulty 4/5 3-5 days Newbie friendliness 28/100

WebAssembly/binaryen#6391 · 3 comments · Opened Mar 8, 2024
wasm-opt wasm port performance Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6338 · 3 comments · Opened Feb 22, 2024
Simplify MemoryPacking output when traps never happen Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6263 · Opened Jan 31, 2024
Questions Related to the Validation of Raw Input Bytes in C API Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#6194 · 1 comment · Opened Jan 2, 2024
[Outlining] Simplify `filter` with a single call Open

WebAssembly/binaryen#6114 · 1 assignee · Opened Nov 13, 2023
[Outlining] Consider replacing state enum with a single `IRBuilder* currBuilder` field Open

WebAssembly/binaryen#6113 · 1 assignee · Opened Nov 13, 2023
[Outlining] Debug need for `existingBuilder.build()` in ReconstructStringifyWalker::startNewFunction Open

WebAssembly/binaryen#6112 · 1 assignee · Opened Nov 12, 2023
[Outlining] Make `StackSignature`store `params` and `results` as a `Signature` Open

WebAssembly/binaryen#6111 · 1 assignee · Opened Nov 12, 2023
Policy on requirements to compile and/or run Binaryen Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

WebAssembly/binaryen#6060 · 23 comments · Opened Oct 27, 2023
wasm2js/I64ToI32Lowering fails on 64-bit atomic stores (I think) test_atomic_wait64_notify Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#5991 · 8 comments · Opened Oct 3, 2023
Regression on optimized module size depending on final markers Open

Difficulty 4/5 3-5 days Newbie friendliness 32/100

WebAssembly/binaryen#5932 · 9 comments · Opened Sep 12, 2023
Empty/Leaked `pkg/*_bg.wasm-opt.wasm` file causing parse error on subsequent `wasm-opt` runs Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

WebAssembly/binaryen#5926 · 1 reaction · Opened Sep 8, 2023
Fuzzer iteration takes over an hour Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

WebAssembly/binaryen#5916 · 1 comment · Opened Aug 31, 2023
wasm-ctor-eval: Handle cycles with non-nullable content Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

WebAssembly/binaryen#5913 · Opened Aug 31, 2023
adding bazel support Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#5902 · 13 comments · Opened Aug 26, 2023
wasm-ctor-eval doesn't seem to play well with >2gb memories. Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

WebAssembly/binaryen#5893 · 6 comments · Opened Aug 23, 2023
Add a ControlChildIterator to parallel ValueChildIterator Open

WebAssembly/binaryen#5796 · 1 assignee · Opened Jun 30, 2023
Opportunity to further simplify internal cast representation Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

WebAssembly/binaryen#5755 · 2 comments · Opened Jun 7, 2023
optimise LSBit mask (followed by branch) to use `ctz` Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

WebAssembly/binaryen#5752 · 4 comments · 1 reaction · Opened Jun 5, 2023

WebAssembly/binaryen

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