Tuple globals (#2718)

Since it wasn't easy to support tuples in Asyncify's call support
using temporary functions, we decided to allow tuple-typed globals
after all. This PR adds support for parsing, printing, lowering, and
interpreting tuple globals and also adds validation ensuring that
imported and exported globals do not have tuple types.

1 files changed, 17 insertions, 11 deletions

diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 4354b747a..a39e52b6d 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -546,12 +546,7 @@ SExpressionWasmBuilder::parseParamOrLocal(Element& s, size_t& localIndex) {
         throw ParseException(
           "params may not have tuple types", s[i]->line, s[i]->col);
       }
-      auto& tuple = s[i]->list();
-      std::vector<Type> types;
-      for (size_t j = 0; j < s[i]->size(); ++j) {
-        types.push_back(stringToType(tuple[j]->str()));
-      }
-      type = Type(types);
+      type = elementToType(*s[i]);
     }
     namedParams.emplace_back(name, type);
   }
@@ -886,6 +881,18 @@ Type SExpressionWasmBuilder::stringToType(const char* str,
   throw ParseException(std::string("invalid wasm type: ") + str);
 }
 
+Type SExpressionWasmBuilder::elementToType(Element& s) {
+  if (s.isStr()) {
+    return stringToType(s.str(), false, false);
+  }
+  auto& tuple = s.list();
+  std::vector<Type> types;
+  for (size_t i = 0; i < s.size(); ++i) {
+    types.push_back(stringToType(tuple[i]->str()));
+  }
+  return Type(types);
+}
+
 Type SExpressionWasmBuilder::stringToLaneType(const char* str) {
   if (strcmp(str, "i8x16") == 0) {
     return Type::i32;
@@ -2278,7 +2285,7 @@ void SExpressionWasmBuilder::parseGlobal(Element& s, bool preParseImport) {
   bool exported = false;
   Name importModule, importBase;
   while (i < s.size() && s[i]->isList()) {
-    auto& inner = *s[i];
+    auto& inner = *s[i++];
     if (elementStartsWith(inner, EXPORT)) {
       auto ex = make_unique<Export>();
       ex->name = inner[1]->str();
@@ -2289,16 +2296,15 @@ void SExpressionWasmBuilder::parseGlobal(Element& s, bool preParseImport) {
       }
       wasm.addExport(ex.release());
       exported = true;
-      i++;
     } else if (elementStartsWith(inner, IMPORT)) {
       importModule = inner[1]->str();
       importBase = inner[2]->str();
-      i++;
     } else if (elementStartsWith(inner, MUT)) {
       mutable_ = true;
-      type = stringToType(inner[1]->str());
-      i++;
+      type = elementToType(*inner[1]);
+      break;
     } else {
+      type = elementToType(inner);
       break;
     }
   }