[Feature] Add Attributes?

[jtenner]

I currently am using llvm-bindings for a toy compiler that I might turn into something bigger.

I can currently generate the following llvm using the node module on ubuntu.

; ModuleID = 'main'
source_filename = "main"
target datalayout = "e"

define void @main() {
entry:
  %a = alloca i32, align 4
  %b = alloca i32, align 4
  store i32 41, i32* %a, align 4
  store i32 1, i32* %b, align 4
  %0 = load i32, i32* %a, align 4
  %1 = load i32, i32* %b, align 4
  %add = call i32 @my_import(i32 %0, i32 %1)
  ret void
}

declare i32 @my_import(i32, i32)

This is genuinely awesome and very accessible for node devs and I want to thank you for this effort.

However when I try to use wasm-ld to make a wasm file like this...

ts-node ./src/index.ts

llc mod.ll --march=wasm32 --filetype=obj

wasm-ld \
  --entry main \
  -o mod.wasm \
  --import-undefined \
  mod.o

(module
  (type (;0;) (func (param i32 i32) (result i32)))
  (type (;1;) (func))
  (import "env" "my_import" (func (;0;) (type 0)))
  (func (;1;) (type 1)
    (local i32)
    ...
    )
  (memory (;0;) 2)
  (global (;0;) (mut i32) (i32.const 66560))
  (export "memory" (memory 0))
  (export "main" (func 1)))

It looks like llc compiles mod.ll just fine to a wasm object, and then wasm-ld actually generates the wasm file. This is really great except I want to target wasi and lunatic imports with proper namespaces.

 (import "env" "lunatic.add" (func (;0;) (type 0)))

In clang, you can designate a symbol as imported from an arbitrary modname and name with syntax like attribute((import_module("wasi_snapshot_preview1"), import_name("path_open"))).

Which in LLVM IR appears to translate to something like:

attributes #2 = { [...] "wasm-import-module"="wasi_snapshot_preview1" "wasm-import-name"="path_open" }

and then stick #2 on the declaration.

Is there currently a way to do this programatically using the bindings or is that a true feature request? I would genuinely love to make a compiler that compiles directly to wasm.

[jtenner]

Hey this issue has been open for a month. Is there anything I can do to help?