[Strings] string.is_usv_sequence (#4783)

This implements it as a StringMeasure opcode. They do have the same number of
operands, same trapping behavior, and same return type. They both get a string and
do some inspection of it to return an i32. Perhaps the name could be StringInspect
or something like that, rather than StringMeasure..? But I think for now this might be
good enough, and the spec may change anyhow later.

1 files changed, 19 insertions, 0 deletions

diff --git a/test/lit/strings.wast b/test/lit/strings.wast
index 687de8e3d..d1a9fd053 100644
--- a/test/lit/strings.wast
+++ b/test/lit/strings.wast
@@ -225,4 +225,23 @@
       )
     )
   )
+
+  ;; CHECK:      (func $string.is_usv_sequence (param $ref stringref)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (i32.eqz
+  ;; CHECK-NEXT:    (string.is_usv_sequence
+  ;; CHECK-NEXT:     (local.get $ref)
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $string.is_usv_sequence (param $ref stringref)
+    (drop
+      (i32.eqz ;; validate the output is i32
+        (string.is_usv_sequence
+          (local.get $ref)
+        )
+      )
+    )
+  )
 )