Merge with WebAssembly/stack-switching

Author: dhil

README.md

@@ -1,35 +1,13 @@
+[![CI for specs](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-spec.yml/badge.svg)](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-spec.yml)
+[![CI for interpreter & tests](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-interpreter.yml/badge.svg)](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-interpreter.yml)
+
 # Stack-Switching Proposal for WebAssembly
 
 This repository is a clone of [`WebAssembly/spec`](https://github.com/WebAssembly/spec/). It is meant for discussion, prototype specification, and implementation of a proposal to add
 support for stack-switching.
 
 See the [explainer](proposals/stack-switching/Explainer.md) for a high-level summary of the proposal.
 
-## Previous proposals
-
-The current explainer represents the unification of two previous proposals: Typed Continuations (wasmfx) and Bag of Stacks (bos). (The explainers have now been unified. Once the reference interpreter and examples are adapted for the unified proposal this section will be removed from the README.)
-
-#### Typed Continuations
-
-* See the [explainer](proposals/continuations/Explainer.md) for a high-level summary of the proposal.
-
-* See the [overview](proposals/continuations/Overview.md) for a more formal description of the proposal.
-
-* An [implementation](https://github.com/WebAssembly/stack-switching/tree/wasmfx) is available as an extension to the reference interpreter. It is accesible from the `wasmfx` branch of this repository.
-
-* See the [examples](proposals/continuations/examples) for Wasm code for implementing various different features including lightweight threads, actors, and async/await.
-
-#### Bag of Stacks Proposal
-
-* See the [explainer](proposals/bag-o-stacks/Explainer.md) for a high-level summary of the proposal.
-
-Original README from upstream repository follows.
-
---------------------------------------------------------------------------------
-
-[![CI for specs](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-spec.yml/badge.svg)](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-spec.yml)
-[![CI for interpreter & tests](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-interpreter.yml/badge.svg)](https://github.com/WebAssembly/stack-switching/actions/workflows/ci-interpreter.yml)
-
 # spec
 
 This repository holds the sources for the WebAssembly specification,

interpreter/binary/decode.ml

@@ -1107,7 +1107,7 @@ let import_desc s =
   | 0x01 -> TableImport (table_type s)
   | 0x02 -> MemoryImport (memory_type s)
   | 0x03 -> GlobalImport (global_type s)
-  | 0x04 -> TagImport (at var s)
+  | 0x04 -> TagImport (tag_type s)
   | _ -> error s (pos s - 1) "malformed import kind"
 
 let import s =

interpreter/binary/encode.ml

@@ -974,7 +974,7 @@ struct
     | TableImport t -> byte 0x01; table_type t
     | MemoryImport t -> byte 0x02; memory_type t
     | GlobalImport t -> byte 0x03; global_type t
-    | TagImport t -> byte 0x04; var t
+    | TagImport t -> byte 0x04; tag_type t
 
   let import im =
     let {module_name; item_name; idesc} = im.it in
@@ -1025,8 +1025,8 @@ struct
     section 6 (vec global) gs (gs <> [])
 
   (* Tag section *)
-  let tag tag =
-    tag_type tag.it.tgtype
+  let tag (t : tag) =
+    byte 0x00; var t.it.tgtype
 
   let tag_section ts =
     section 13 (vec tag) ts (ts <> [])

interpreter/text/parser.mly

@@ -591,7 +591,7 @@ instr_list :
   | instr1 instr_list { fun c -> $1 c @ $2 c }
   | select_instr_instr_list { $1 }
   | call_instr_instr_list { $1 }
-  | resume_instr_instr { fun c -> let e, es = $1 c in e :: es }
+  | resume_instr_instr_list { $1 }
 
 instr1 :
   | plain_instr { fun c -> [$1 c @@ $sloc] }
@@ -769,25 +769,25 @@ call_instr_results_instr_list :
   | instr_list
     { fun c -> [], $1 c }
 
-resume_instr_instr :
+resume_instr_instr_list :
   | RESUME var resume_instr_handler_instr
     { let loc1 = $loc($1) in
       fun c ->
       let x = $2 c type_ in
-      let hs, es = $3 c in resume x hs @@ loc1, es }
+      let hs, es = $3 c in (resume x hs @@ loc1) :: es }
   | RESUME_THROW var var resume_instr_handler_instr
     { let loc1 = $loc($1) in
       fun c ->
       let x  = $2 c type_ in
       let tag = $3 c tag in
-      let hs, es = $4 c in resume_throw x tag hs @@ loc1, es }
+      let hs, es = $4 c in (resume_throw x tag hs @@ loc1) :: es }
 
 resume_instr_handler_instr :
   | LPAR ON var var RPAR resume_instr_handler_instr
     { fun c -> let hs, es = $6 c in ($3 c tag, OnLabel ($4 c label)) :: hs, es }
   | LPAR ON var SWITCH RPAR resume_instr_handler_instr
     { fun c -> let hs, es = $6 c in ($3 c tag, OnSwitch) :: hs, es }
-  | instr1
+  | instr_list
     { fun c -> [], $1 c }
 
 block_instr :

interpreter/valid/valid.ml

@@ -651,14 +651,15 @@ let rec check_instr (c : context) (e : instr) (s : infer_result_type) : infer_in
               " but the type annotation has " ^ string_of_result_type ts11)
      in
      let et = tag c y in
-     let FuncT (_, t) as ft = func_type_of_tag_type c et y.at in
-     require (match_func_type c.types (FuncT ([], t)) ft) y.at
+     let FuncT (ts31, t) = func_type_of_tag_type c et y.at in
+     require (ts31 = []) y.at
        "type mismatch in switch tag";
      require (match_result_type c.types ts12 t) y.at
        "type mismatch in continuation types";
      require (match_result_type c.types t ts22) y.at
        "type mismatch in continuation types";
-     ts11 --> ts21, []
+     let ts11' = Lib.List.lead ts11 in
+     (ts11' @ [RefT (Null, VarHT (StatX x.it))]) --> ts21, []
 
   | Throw x ->
     let FuncT (ts1, ts2) = func_type_of_tag_type c (tag c x) x.at in

proposals/stack-switching/Explainer.md

@@ -842,7 +842,7 @@ We extend the binary format of composite types, heap types, and instructions.
 | Opcode | Type            | Parameters | Note |
 | ------ | --------------- | ---------- |------|
 | -0x20  | `func t1* t2*`  | `t1* : vec(valtype)` `t2* : vec(valtype)` | from Wasm 1.0 |
-| -0x23  | `cont $ft`      | `$ft : typeidx` | new |
+| -0x23  | `cont $ft`      | `$ft : s33` | new |
 
 #### Heap Types