GC: Add i31 instructions (#3154)

Adds the `i31.new` and `i31.get_s/u` instructions for creating and working with `i31ref` typed values. Does not include fuzzer integration just yet because the fuzzer expects that trivial values it creates are suitable in global initializers, which is not the case for trivial `i31ref` expressions.

1 files changed, 22 insertions, 0 deletions

diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index c1df740df..d55f60009 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -337,6 +337,8 @@ public:
   void visitBrOnExn(BrOnExn* curr);
   void visitTupleMake(TupleMake* curr);
   void visitTupleExtract(TupleExtract* curr);
+  void visitI31New(I31New* curr);
+  void visitI31Get(I31Get* curr);
   void visitFunction(Function* curr);
 
   // helpers
@@ -2109,6 +2111,26 @@ void FunctionValidator::visitTupleExtract(TupleExtract* curr) {
   }
 }
 
+void FunctionValidator::visitI31New(I31New* curr) {
+  shouldBeTrue(
+    getModule()->features.hasGC(), curr, "i31.new requires gc to be enabled");
+  shouldBeSubTypeOrFirstIsUnreachable(curr->value->type,
+                                      Type::i32,
+                                      curr->value,
+                                      "i31.new's argument should be i32");
+}
+
+void FunctionValidator::visitI31Get(I31Get* curr) {
+  shouldBeTrue(getModule()->features.hasGC(),
+               curr,
+               "i31.get_s/u requires gc to be enabled");
+  shouldBeSubTypeOrFirstIsUnreachable(
+    curr->i31->type,
+    Type::i31ref,
+    curr->i31,
+    "i31.get_s/u's argument should be i31ref");
+}
+
 void FunctionValidator::visitFunction(Function* curr) {
   if (curr->sig.results.isTuple()) {
     shouldBeTrue(getModule()->features.hasMultivalue(),