[Strings] Fuzz and interpret all relevant StringNew methods (#6526)

This adds fuzzing for string.new_wtf16_array and string.from_code_point. The
latter was also missing interpreter support, which this adds.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
index 64c0bfb2d..0afbaba94 100644
--- a/src/wasm-interpreter.h
+++ b/src/wasm-interpreter.h
@@ -33,6 +33,7 @@
 #include "support/bits.h"
 #include "support/safe_integer.h"
 #include "support/stdckdint.h"
+#include "support/string.h"
 #include "wasm-builder.h"
 #include "wasm-traversal.h"
 #include "wasm.h"
@@ -1898,6 +1899,16 @@ public:
         }
         return makeGCData(contents, curr->type);
       }
+      case StringNewFromCodePoint: {
+        uint32_t codePoint = ptr.getSingleValue().getUnsigned();
+        if (codePoint > 0x10FFFF) {
+          trap("invalid code point");
+        }
+        std::stringstream wtf16;
+        String::writeWTF16CodePoint(wtf16, codePoint);
+        std::string str = wtf16.str();
+        return Literal(str);
+      }
       default:
         // TODO: others
         return Flow(NONCONSTANT_FLOW);