[Strings] Add string.const (#4768)

This is more work than a typical instruction because it also adds a new section:
all the (string.const "foo") strings are put in a new "strings" section in the binary, and
the instructions refer to them by index.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/wasm.h b/src/wasm.h
index 6d0733d34..3032b4ac1 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -686,6 +686,7 @@ public:
     ArrayCopyId,
     RefAsId,
     StringNewId,
+    StringConstId,
     NumExpressionIds
   };
   Id _id;
@@ -1664,6 +1665,18 @@ public:
   void finalize();
 };
 
+class StringConst : public SpecificExpression<Expression::StringConstId> {
+public:
+  StringConst(MixedArena& allocator) {}
+
+  // TODO: Use a different type to allow null bytes in the middle -
+  //       ArenaVector<char> perhaps? However, Name has the benefit of being
+  //       interned and immutable (which is appropriate here).
+  Name string;
+
+  void finalize();
+};
+
 // Globals
 
 struct Named {