[Strings] Initial string execution support (#5491)

Store string data as GC data. Inefficient (one Const per char), but ok for now.

Implement string.new_wtf16 and string.const, enough for basic testing.

Create strings in makeConstantExpression, which enables ctor-eval support.

Print strings in fuzz-exec which makes testing easier.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/tools/execution-results.h b/src/tools/execution-results.h
index 925c9b6d8..d12c84d1e 100644
--- a/src/tools/execution-results.h
+++ b/src/tools/execution-results.h
@@ -116,12 +116,15 @@ struct ExecutionResults {
           if (values->size() > 0) {
             std::cout << "[fuzz-exec] note result: " << exp->name << " => ";
             auto resultType = func->getResults();
-            if (resultType.isRef()) {
+            if (resultType.isRef() && !resultType.isString()) {
               // Don't print reference values, as funcref(N) contains an index
               // for example, which is not guaranteed to remain identical after
               // optimizations.
               std::cout << resultType << '\n';
             } else {
+              // Non-references can be printed in full. So can strings, since we
+              // always know how to print them and there is just one string
+              // type.
               std::cout << *values << '\n';
             }
           }