Stephan Renatus 2e122c9e69 wasm: read/write custom sections (incl. dwarf), deal with Name section specifically (#2900) ...

* wasm: read/write custom sections (incl. dwarf)

I've extended the roundtrip OPA test to have some assertions
on custom sections that work for both debug and non-debug
wasm builds.

Without debugging enabled, we had still been stripping the
`names` and `producers` sections. This changes therefore
increases the size of wasm modules. For a simple policy,

    package test
    default allow = false
    allow {
        input.foo == "bar"
    }

the size generated is 544K (master) vs 620K (this commit).

With debugging enabled (and the opa binary rebuilt), the
size becomes 6.1M.

* wasm/encoding: treat 'name' custom section separately

This roundtrips module, functions, and locals, as per
https://webassembly.github.io/spec/core/appendix/custom.html#name-section

There is currently no use of module and locals, afaict.

* compiler/wasm: record function names in 'name' custom section

Quality-of-life improvement when dealing with our generated WASM
code.

Before:

    local.get 2
    local.get 3
    call 1172
    local.set 6

After:

    local.get 2
    local.get 3
    call $g0.data.foo.p
    local.set 6

Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>

2021-01-13 09:30:39 +01:00

..

constant.go

wasm: read/write custom sections (incl. dwarf), deal with Name section specifically (#2900)

2021-01-13 09:30:39 +01:00