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, 15 insertions, 0 deletions

diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 1bb83ec94..166fc88bb 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -1979,6 +1979,21 @@ Expression* SExpressionWasmBuilder::makeTupleExtract(Element& s) {
   return ret;
 }
 
+Expression* SExpressionWasmBuilder::makeI31New(Element& s) {
+  auto ret = allocator.alloc<I31New>();
+  ret->value = parseExpression(s[1]);
+  ret->finalize();
+  return ret;
+}
+
+Expression* SExpressionWasmBuilder::makeI31Get(Element& s, bool signed_) {
+  auto ret = allocator.alloc<I31Get>();
+  ret->i31 = parseExpression(s[1]);
+  ret->signed_ = signed_;
+  ret->finalize();
+  return ret;
+}
+
 // converts an s-expression string representing binary data into an output
 // sequence of raw bytes this appends to data, which may already contain
 // content.