wasm-ctor-eval: Eval strings

src/tools/wasm-ctor-eval.cpp

@@ -889,6 +889,12 @@ struct CtorEvalExternalInterface : EvallingModuleRunner::ExternalInterface {
       } else if (heapType.isArray()) {
         // TODO: for repeated identical values, can use ArrayNew
         init = builder.makeArrayNewFixed(heapType, args);
+      } else if (heapType.isString()) {
+        std::string s;
+        for (auto c : values) {
+          s += char(c.getInteger());
+        }
+        init = builder.makeStringConst(s);
       } else {
         WASM_UNREACHABLE("bad gc type");
       }

test/lit/ctor-eval/string.wast

@@ -0,0 +1,23 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; RUN: foreach %s %t wasm-ctor-eval --ctors=test --kept-exports=test --quiet -all -S -o - | filecheck %s
+
+;; We should not error on precomputing this string. Nothing should change in
+;; the output, as precomputing a string results in an identical string.
+
+(module
+ ;; CHECK:      (type $0 (func (result anyref)))
+
+ ;; CHECK:      (global $global (ref string) (string.const "one"))
+ (global $global (ref string) (string.const "one"))
+
+ (export "test" (func $test))
+
+ (func $test (result anyref)
+  (global.get $global)
+ )
+)
+;; CHECK:      (export "test" (func $test_1))
+
+;; CHECK:      (func $test_1 (type $0) (result anyref)
+;; CHECK-NEXT:  (global.get $global)
+;; CHECK-NEXT: )