Toolchain 🛠️

Since we use toolchain based on modified version of TinyGo for compiling Go to Wasm, some of Go's language capabilities cannot be applied due to the limited support in TinyGo which also affects some of the design decisions.

1. TinyGo modifications

There are several changes made to TinyGo in order to make it compatible with Polkadot's Wasm target:

1.1. New target 🎯

• polkawasm - targeting standalone Wasm MVP, similar to Rust's wasm32-unknown-unknown.

1.2. Custom garbage collector 🗑️

• extalloc - custom GC that utilizes an external allocator (as per Polkadot specification). It is conservative, tracing (mark and sweep) garbage collector that relies on an external memory allocator (viaext_allocator_malloc, ext_allocator_free) for the WebAssembly (polkawasm) target.
• extalloc_leaking - leaking GC implementation that only allocates memory through the external allocator, but never frees it (not a real GC), however, it is useful for testing purposes and performance comparisons.

1.3. Wasi-libc 🔩

• fork with disabled bulk memory operations.

1.4. Binaryen 🔩

• version that lowers away the sign extension operations in wasm-opt.