Represent ref.as_{func,data,i31} with RefCast (#5413)

These operations are deprecated and directly representable as casts, so remove
their opcodes in the internal IR and parse them as casts instead. For now, add
logic to the printing and binary writing of RefCast to continue emitting the
legacy instructions to minimize test changes. The few test changes necessary are
because it is no longer valid to perform a ref.as_func on values outside the
func type hierarchy now that ref.as_func is subject to the ref.cast validation
rules.

RefAsExternInternalize, RefAsExternExternalize, and RefAsNonNull are left
unmodified. A future PR may remove RefAsNonNull as well, since it is also
expressible with casts.

6 files changed, 31 insertions, 130 deletions

diff --git a/test/lit/binary/bad-ref-as.test b/test/lit/binary/bad-ref-as.test
index 2afa19904..3accdd553 100644
--- a/test/lit/binary/bad-ref-as.test
+++ b/test/lit/binary/bad-ref-as.test
@@ -1,6 +1,5 @@
 ;; Test that we error properly on a file with a ref.as of a non-ref type.
 
-;; RUN: not wasm-opt %s.wasm 2>&1 | filecheck %s
-
-;; CHECK: parse exception: bad input type for ref.as: i32
+;; RUN: not wasm-opt -all %s.wasm 2>&1 | filecheck %s
 
+;; CHECK: ref.cast ref must have ref type
diff --git a/test/lit/passes/gufa-extern.wast b/test/lit/passes/gufa-extern.wast
index 2c38a0118..9d71357aa 100644
--- a/test/lit/passes/gufa-extern.wast
+++ b/test/lit/passes/gufa-extern.wast
@@ -39,10 +39,13 @@
 
   ;; CHECK:      (func $non-exported (type $externref_anyref_=>_none) (param $ext externref) (param $any anyref)
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (ref.as_data
-  ;; CHECK-NEXT:    (extern.internalize
-  ;; CHECK-NEXT:     (unreachable)
+  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (extern.internalize
+  ;; CHECK-NEXT:      (unreachable)
+  ;; CHECK-NEXT:     )
   ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
diff --git a/test/lit/passes/optimize-instructions-gc-tnh.wast b/test/lit/passes/optimize-instructions-gc-tnh.wast
index 948e03296..502590cde 100644
--- a/test/lit/passes/optimize-instructions-gc-tnh.wast
+++ b/test/lit/passes/optimize-instructions-gc-tnh.wast
@@ -86,9 +86,7 @@
   ;; TNH:      (func $ref.is (type $eqref_=>_i32) (param $a eqref) (result i32)
   ;; TNH-NEXT:  (drop
   ;; TNH-NEXT:   (ref.cast $struct
-  ;; TNH-NEXT:    (ref.as_data
-  ;; TNH-NEXT:     (local.get $a)
-  ;; TNH-NEXT:    )
+  ;; TNH-NEXT:    (local.get $a)
   ;; TNH-NEXT:   )
   ;; TNH-NEXT:  )
   ;; TNH-NEXT:  (i32.const 0)
@@ -96,9 +94,7 @@
   ;; NO_TNH:      (func $ref.is (type $eqref_=>_i32) (param $a eqref) (result i32)
   ;; NO_TNH-NEXT:  (drop
   ;; NO_TNH-NEXT:   (ref.cast $struct
-  ;; NO_TNH-NEXT:    (ref.as_data
-  ;; NO_TNH-NEXT:     (local.get $a)
-  ;; NO_TNH-NEXT:    )
+  ;; NO_TNH-NEXT:    (local.get $a)
   ;; NO_TNH-NEXT:   )
   ;; NO_TNH-NEXT:  )
   ;; NO_TNH-NEXT:  (i32.const 0)
@@ -140,23 +136,23 @@
     )
   )
 
-  ;; TNH:      (func $ref.is_func (type $anyref_=>_i32) (param $a anyref) (result i32)
+  ;; TNH:      (func $ref.is_func (type $funcref_=>_i32) (param $a funcref) (result i32)
   ;; TNH-NEXT:  (drop
-  ;; TNH-NEXT:   (ref.as_func
+  ;; TNH-NEXT:   (ref.as_non_null
   ;; TNH-NEXT:    (local.get $a)
   ;; TNH-NEXT:   )
   ;; TNH-NEXT:  )
   ;; TNH-NEXT:  (i32.const 1)
   ;; TNH-NEXT: )
-  ;; NO_TNH:      (func $ref.is_func (type $anyref_=>_i32) (param $a anyref) (result i32)
+  ;; NO_TNH:      (func $ref.is_func (type $funcref_=>_i32) (param $a funcref) (result i32)
   ;; NO_TNH-NEXT:  (drop
-  ;; NO_TNH-NEXT:   (ref.as_func
+  ;; NO_TNH-NEXT:   (ref.as_non_null
   ;; NO_TNH-NEXT:    (local.get $a)
   ;; NO_TNH-NEXT:   )
   ;; NO_TNH-NEXT:  )
   ;; NO_TNH-NEXT:  (i32.const 1)
   ;; NO_TNH-NEXT: )
-  (func $ref.is_func (param $a (ref null any)) (result i32)
+  (func $ref.is_func (param $a funcref) (result i32)
     ;; The check must succeed. We can return 1 here, and drop the rest, with or
     ;; without TNH (in particular, TNH should not just remove the cast but not
     ;; return a 1).
diff --git a/test/lit/passes/optimize-instructions-gc.wast b/test/lit/passes/optimize-instructions-gc.wast
index e6ee4784a..631697e27 100644
--- a/test/lit/passes/optimize-instructions-gc.wast
+++ b/test/lit/passes/optimize-instructions-gc.wast
@@ -366,95 +366,6 @@
     )
   )
 
-  ;; similar to $unneeded_as, but the values are of mixed kind (as_func of
-  ;; data, etc.), so we know we will trap
-  ;; CHECK:      (func $unneeded_as_bad_kinds (type $funcref_dataref_i31ref_=>_none) (param $func funcref) (param $struct dataref) (param $i31 i31ref)
-  ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block (result (ref func))
-  ;; CHECK-NEXT:    (drop
-  ;; CHECK-NEXT:     (local.get $struct)
-  ;; CHECK-NEXT:    )
-  ;; CHECK-NEXT:    (unreachable)
-  ;; CHECK-NEXT:   )
-  ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block (result (ref i31))
-  ;; CHECK-NEXT:    (drop
-  ;; CHECK-NEXT:     (local.get $func)
-  ;; CHECK-NEXT:    )
-  ;; CHECK-NEXT:    (unreachable)
-  ;; CHECK-NEXT:   )
-  ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block (result (ref func))
-  ;; CHECK-NEXT:    (drop
-  ;; CHECK-NEXT:     (local.get $struct)
-  ;; CHECK-NEXT:    )
-  ;; CHECK-NEXT:    (unreachable)
-  ;; CHECK-NEXT:   )
-  ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block (result (ref i31))
-  ;; CHECK-NEXT:    (drop
-  ;; CHECK-NEXT:     (local.get $func)
-  ;; CHECK-NEXT:    )
-  ;; CHECK-NEXT:    (unreachable)
-  ;; CHECK-NEXT:   )
-  ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT: )
-  ;; NOMNL:      (func $unneeded_as_bad_kinds (type $funcref_dataref_i31ref_=>_none) (param $func funcref) (param $struct dataref) (param $i31 i31ref)
-  ;; NOMNL-NEXT:  (drop
-  ;; NOMNL-NEXT:   (block (result (ref func))
-  ;; NOMNL-NEXT:    (drop
-  ;; NOMNL-NEXT:     (local.get $struct)
-  ;; NOMNL-NEXT:    )
-  ;; NOMNL-NEXT:    (unreachable)
-  ;; NOMNL-NEXT:   )
-  ;; NOMNL-NEXT:  )
-  ;; NOMNL-NEXT:  (drop
-  ;; NOMNL-NEXT:   (block (result (ref i31))
-  ;; NOMNL-NEXT:    (drop
-  ;; NOMNL-NEXT:     (local.get $func)
-  ;; NOMNL-NEXT:    )
-  ;; NOMNL-NEXT:    (unreachable)
-  ;; NOMNL-NEXT:   )
-  ;; NOMNL-NEXT:  )
-  ;; NOMNL-NEXT:  (drop
-  ;; NOMNL-NEXT:   (block (result (ref func))
-  ;; NOMNL-NEXT:    (drop
-  ;; NOMNL-NEXT:     (local.get $struct)
-  ;; NOMNL-NEXT:    )
-  ;; NOMNL-NEXT:    (unreachable)
-  ;; NOMNL-NEXT:   )
-  ;; NOMNL-NEXT:  )
-  ;; NOMNL-NEXT:  (drop
-  ;; NOMNL-NEXT:   (block (result (ref i31))
-  ;; NOMNL-NEXT:    (drop
-  ;; NOMNL-NEXT:     (local.get $func)
-  ;; NOMNL-NEXT:    )
-  ;; NOMNL-NEXT:    (unreachable)
-  ;; NOMNL-NEXT:   )
-  ;; NOMNL-NEXT:  )
-  ;; NOMNL-NEXT: )
-  (func $unneeded_as_bad_kinds
-    (param $func (ref null func))
-    (param $struct (ref null struct))
-    (param $i31 (ref null i31))
-    (drop
-      (ref.as_func (local.get $struct))
-    )
-    (drop
-      (ref.as_i31 (local.get $func))
-    )
-    ;; also check non-nullable types as inputs
-    (drop
-      (ref.as_func (ref.as_non_null (local.get $struct)))
-    )
-    (drop
-      (ref.as_i31 (ref.as_non_null (local.get $func)))
-    )
-  )
-
   ;; CHECK:      (func $unneeded_unreachability (type $void)
   ;; CHECK-NEXT:  (drop
   ;; CHECK-NEXT:   (ref.is_func
@@ -462,7 +373,10 @@
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (ref.as_func
+  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (unreachable)
+  ;; CHECK-NEXT:    )
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
@@ -474,7 +388,10 @@
   ;; NOMNL-NEXT:   )
   ;; NOMNL-NEXT:  )
   ;; NOMNL-NEXT:  (drop
-  ;; NOMNL-NEXT:   (ref.as_func
+  ;; NOMNL-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; NOMNL-NEXT:    (drop
+  ;; NOMNL-NEXT:     (unreachable)
+  ;; NOMNL-NEXT:    )
   ;; NOMNL-NEXT:    (unreachable)
   ;; NOMNL-NEXT:   )
   ;; NOMNL-NEXT:  )
@@ -3129,12 +3046,18 @@
   )
 
   ;; CHECK:      (func $as_of_unreachable (type $none_=>_ref|data|) (result (ref data))
-  ;; CHECK-NEXT:  (ref.as_data
+  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (drop
+  ;; CHECK-NEXT:    (unreachable)
+  ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:   (unreachable)
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT: )
   ;; NOMNL:      (func $as_of_unreachable (type $none_=>_ref|data|) (result (ref data))
-  ;; NOMNL-NEXT:  (ref.as_data
+  ;; NOMNL-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; NOMNL-NEXT:   (drop
+  ;; NOMNL-NEXT:    (unreachable)
+  ;; NOMNL-NEXT:   )
   ;; NOMNL-NEXT:   (unreachable)
   ;; NOMNL-NEXT:  )
   ;; NOMNL-NEXT: )
diff --git a/test/lit/passes/vacuum-gc.wast b/test/lit/passes/vacuum-gc.wast
index c7ff5a37f..c131bef20 100644
--- a/test/lit/passes/vacuum-gc.wast
+++ b/test/lit/passes/vacuum-gc.wast
@@ -12,11 +12,6 @@
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (ref.as_func
-  ;; CHECK-NEXT:    (local.get $x)
-  ;; CHECK-NEXT:   )
-  ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (drop
   ;; CHECK-NEXT:   (ref.as_data
   ;; CHECK-NEXT:    (local.get $x)
   ;; CHECK-NEXT:   )
@@ -36,11 +31,6 @@
       )
     )
     (drop
-      (ref.as_func
-        (local.get $x)
-      )
-    )
-    (drop
       (ref.as_data
         (local.get $x)
       )
diff --git a/test/lit/passes/vacuum-tnh.wast b/test/lit/passes/vacuum-tnh.wast
index c1e8c2059..40aac16c1 100644
--- a/test/lit/passes/vacuum-tnh.wast
+++ b/test/lit/passes/vacuum-tnh.wast
@@ -27,11 +27,6 @@
   ;; NO_TNH-NEXT:   )
   ;; NO_TNH-NEXT:  )
   ;; NO_TNH-NEXT:  (drop
-  ;; NO_TNH-NEXT:   (ref.as_func
-  ;; NO_TNH-NEXT:    (local.get $y)
-  ;; NO_TNH-NEXT:   )
-  ;; NO_TNH-NEXT:  )
-  ;; NO_TNH-NEXT:  (drop
   ;; NO_TNH-NEXT:   (ref.as_data
   ;; NO_TNH-NEXT:    (local.get $y)
   ;; NO_TNH-NEXT:   )
@@ -61,11 +56,6 @@
 
     ;; Other ref.as* as well.
     (drop
-      (ref.as_func
-        (local.get $y)
-      )
-    )
-    (drop
       (ref.as_data
         (local.get $y)
       )