chore: add some externref usage to tests

test/test.expected

@@ -1,11 +1,15 @@
 (module
  (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
  (type $none_=>_none (func))
+ (type $externref_=>_i32 (func (param externref) (result i32)))
+ (type $externref_i32_i32_=>_i32 (func (param externref i32 i32) (result i32)))
+ (import "future-wasi" "write" (func $write (param externref i32 i32) (result i32)))
  (memory $0 1)
  (table $table 1 1 funcref)
  (elem $elem (i32.const 0) $adder)
  (export "adder" (func $adder))
  (export "memory" (memory $0))
+ (export "hello" (func $hello))
  (start $start)
  (func $adder (param $0 i32) (param $1 i32) (result i32)
   (block $add (result i32)
@@ -34,15 +38,26 @@
    )
   )
  )
+ (func $hello (param $0 externref) (result i32)
+  (call $write
+   (local.get $0)
+   (i32.const 0)
+   (i32.const 1)
+  )
+ )
 )
 (module
  (type $none_=>_none (func))
+ (type $externref_=>_i32 (func (param externref) (result i32)))
  (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
+ (type $externref_i32_i32_=>_i32 (func (param externref i32 i32) (result i32)))
+ (import "future-wasi" "write" (func $write (param externref i32 i32) (result i32)))
  (memory $0 1)
  (table $table 1 1 funcref)
  (elem $elem (i32.const 0) $adder)
  (export "adder" (func $adder))
  (export "memory" (memory $0))
+ (export "hello" (func $hello))
  (start $start)
  (func $adder (; has Stack IR ;) (param $0 i32) (param $1 i32) (result i32)
   (i32.add
@@ -64,15 +79,26 @@
    )
   )
  )
+ (func $hello (; has Stack IR ;) (param $0 externref) (result i32)
+  (call $write
+   (local.get $0)
+   (i32.const 0)
+   (i32.const 1)
+  )
+ )
 )
 (module
  (type $none_=>_none (func))
+ (type $externref_=>_i32 (func (param externref) (result i32)))
  (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
+ (type $externref_i32_i32_=>_i32 (func (param externref i32 i32) (result i32)))
+ (import "future-wasi" "write" (func $fimport$0 (param externref i32 i32) (result i32)))
  (memory $0 1)
  (table $0 1 1 funcref)
  (elem (i32.const 0) $0)
  (export "adder" (func $0))
  (export "memory" (memory $0))
+ (export "hello" (func $2))
  (start $1)
  (func $0 (param $0 i32) (param $1 i32) (result i32)
   (i32.add
@@ -94,4 +120,11 @@
    )
   )
  )
+ (func $2 (param $0 externref) (result i32)
+  (call $fimport$0
+   (local.get $0)
+   (i32.const 0)
+   (i32.const 1)
+  )
+ )
 )

test/test.ml

@@ -3,7 +3,7 @@ open Binaryen
 let wasm_mod = Module.create ()
 
 (* Create function type for i32 (i32, i32) *)
-let params () = Type.create [| Type.int32; Type.int32 |]
+let params () = Type.create [| Type.int32; Type.int32 |] 
 
 let results = Type.int32
 
@@ -58,12 +58,40 @@ let _ = Function.set_start wasm_mod start
 
 let _ = Memory.set_memory wasm_mod 1 Memory.unlimited "memory" [] false
 
+
+(* Create an imported "write" function i32 (externref, i32, i32) *)
+(* Similar to the example here: https://bytecodealliance.org/articles/reference-types-in-wasmtime *)
+
+let _ = Import.add_function_import wasm_mod "write" "future-wasi" "write"
+  (Type.create [| Type.externref; Type.int32; Type.int32 |])
+  Type.int32
+
+(* Create a function that calls the imported write function *)
+let _ = Function.add_function wasm_mod "hello" Type.externref Type.int32 [||]
+  (Expression.call wasm_mod "write"
+  [
+    Expression.local_get wasm_mod 0 Type.externref;
+    Expression.const wasm_mod (Literal.int32 0l);
+    Expression.const wasm_mod (Literal.int32 1l);
+  ]
+  Type.int32)
+
+let _ = Export.add_function_export wasm_mod "hello" "hello"
+
+(* Finally, we print 3 versions of the module to be checked against test.expected *)
+
+(* 1. Print the the module as-is *)
+
 let _ = Module.print wasm_mod
 
+(* 2. Optimize, then print the module *)
+
 let _ = Module.optimize wasm_mod
 
 let _ = Module.print wasm_mod
 
+(* 3. Copy previous module bytes into new module, validate, and print *)
+
 let byts, _ = Module.write wasm_mod None
 
 let new_mod = Module.read byts
@@ -72,6 +100,8 @@ let _ = Module.validate new_mod
 
 let _ = Module.print new_mod
 
+(* Dispose the modules 👋 *)
+
 let _ = Module.dispose wasm_mod
 
 let _ = Module.dispose new_mod