wast2json —
convert a file in the wasm spec test format to a JSON file and
  associated wasm binary files
wast2json reads a file in the wasm spec test format,
  checks it for errors, and converts it to a JSON file and associated wasm
  binary files.
The options are as follows:
  - -v,- -- -verbose
- Use multiple times for more info
- -- -help
- Print this help message
- -- -debug-parser
- Turn on debugging the parser of wast files
- -- -enable-exceptions
- Enable Experimental exception handling
- -- -disable-mutable-globals
- Disable Import/export mutable globals
- -- -enable-saturating-float-to-int
- Enable Saturating float-to-int operators
- -- -enable-sign-extension
- Enable Sign-extension operators
- -- -disable-simd
- Disable SIMD support
- -- -enable-threads
- Enable Threading support
- -- -enable-multi-value
- Enable Multi-value
- -- -enable-tail-call
- Enable Tail-call support
- -o,- -- -output=FILE
- output wasm binary file
- -r,- -- -relocatable
- Create a relocatable wasm binary (suitable for linking with e.g. lld)
- -- -no-canonicalize-leb128s
- Write all LEB128 sizes as 5-bytes instead of their minimal size
- -- -debug-names
- Write debug names to the generated binary file
- -- -no-check
- Don't check for invalid modules
Parse spec-test.wast, and write files to spec-test.json. Modules are written to
  spec-test.0.wasm, spec-test.1.wasm, etc.$ wast2json spec-test.wast -o
  spec-test.json