emited text contains tuple instructions even when using --intrinsic-lowering

[zapashcanon]

Hi,

I'm running Binaryen with -S (because I'm using a combination of proposals not handled by other tools yet) in order to debug some code. I added the --intrinsic-lowering flag, hoping it would remove the tuples and use locals or whatever instead but it seems this is not the case.

Is there a way to get rid of them in the text format generated by Binaryen? Binaryen is able to produce a binary file so what I'd like is to get the equivalent text format.

This is related to #6016 but it's really not helping me.

Thanks!

[kripken]

Tuples are not intrinsic functions, they are a normal part of the IR, so that pass does not affect them.

You can print StackIR, --print-stack-ir, which is after tuples are lowered away. For debugging that might be enough, depending on what you want to do with it (I'm not sure which tools can read it).

[zapashcanon]

Thanks!

[zapashcanon]

Acutally, when using --print-stack-ir the output is different but still contains tuples, I guess this is not expected ?

[kripken]

Hmm, yeah, I suppose it doesn't remove them entirely, e.g. this

(module
 (type $0 (func (result i32 f64)))
 (func $foo (type $0) (result i32 f64)
  (tuple.make 2
   (i32.const 42)
   (f64.const 3.14159)
  )
 )
)

is printed as this Stack IR:

(module
 (type $0 (func (result i32 f64)))
 (func $foo (type $0) (result i32 f64)
  i32.const 42
  f64.const 3.14159
  tuple.make 2
 )
)

This is in the flat format that doesn't need tuples, so we could skip printing tuple.make there. We do skip those in the binary writing, but Stack IR printing is mainly for debug reasons so this wasn't noticed. It would make sense to fix this.

[zapashcanon]

Yes, it would be nice to get rid of them. I'm trying to run Binaryen generated file in the reference interpreter and in Owi and it complicates things.

[kripken]

If this is for manual debugging, you can ignore the tuple.* instructions in the output. But if you want some other tool to consume this format, that might require more work, I'm not sure how much offhand.

[tlively]

We could print the tuple instructions as comments in Stack IR, perhaps.

[kripken]

@zapashcanon You may also want to look at other tools for printing the wasm, such as wasm-tools or v8's wami.

[zapashcanon]

We could print the tuple instructions as comments in Stack IR, perhaps.

I think this would solve the issue for me.

[tlively]

Oh, it looks like Stack IR still contains tuple.extract instructions that would require scratch locals to lower away, so just printing tuple.make as a comment would not be enough. That's enough complexity that it might warrant a completely new printing mode based on the binary writer if we want to support it at all.

Your best bet for now would be to have Binaryen emit a binary module, then use a separate tool (probably https://github.com/bytecodealliance/wasm-tools) to disassemble it back to text.