Update `tuple.make` text format to include arity (#6169)

Previously, the number of tuple elements was inferred from the number of
s-expression children of the `tuple.make` expression, but that scheme would not
work in the new wat parser, where s-expressions are optional and cannot be
semantically meaningful.

Update the text format to take the number of tuple elements (i.e. the tuple
arity) as an immediate. This new format will be able to be implemented in the
new parser as follow-on work.

4 files changed, 11 insertions, 4 deletions

diff --git a/src/passes/Flatten.cpp b/src/passes/Flatten.cpp
index 3c0aa78a0..8ddd8632a 100644
--- a/src/passes/Flatten.cpp
+++ b/src/passes/Flatten.cpp
@@ -24,7 +24,7 @@
 //       (func $foo
 //        (drop
 //         (block (result funcref (ref $none))
-//          (tuple.make
+//          (tuple.make 2
 //           (ref.null func)
 //           (ref.func $foo)
 //          )
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 889eb87fd..9a0a600f9 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -1985,7 +1985,10 @@ struct PrintExpressionContents
     }
     restoreNormalColor(o);
   }
-  void visitTupleMake(TupleMake* curr) { printMedium(o, "tuple.make"); }
+  void visitTupleMake(TupleMake* curr) {
+    printMedium(o, "tuple.make ");
+    o << curr->operands.size();
+  }
   void visitTupleExtract(TupleExtract* curr) {
     printMedium(o, "tuple.extract ");
     o << curr->index;
diff --git a/src/passes/TupleOptimization.cpp b/src/passes/TupleOptimization.cpp
index e4fb1cf00..16a2bad58 100644
--- a/src/passes/TupleOptimization.cpp
+++ b/src/passes/TupleOptimization.cpp
@@ -20,7 +20,7 @@
 // like this:
 //
 //  (local.set $tuple
-//    (tuple.make (A) (B) (C)))
+//    (tuple.make 3 (A) (B) (C)))
 //  (use
 //    (tuple.extract 0
 //      (local.get $tuple)))
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 9e16d34e6..8e74820a9 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -2858,7 +2858,11 @@ Expression* SExpressionWasmBuilder::makeRethrow(Element& s) {
 
 Expression* SExpressionWasmBuilder::makeTupleMake(Element& s) {
   auto ret = allocator.alloc<TupleMake>();
-  parseCallOperands(s, 1, s.size(), ret);
+  size_t arity = std::stoll(s[1]->toString());
+  if (arity != s.size() - 2) {
+    throw SParseException("unexpected number of elements", s, *s[1]);
+  }
+  parseCallOperands(s, 2, s.size(), ret);
   ret->finalize();
   return ret;
 }