Add support for reference types proposal (#2451)

This adds support for the reference type proposal. This includes support
for all reference types (`anyref`, `funcref`(=`anyfunc`), and `nullref`)
and four new instructions: `ref.null`, `ref.is_null`, `ref.func`, and
new typed `select`. This also adds subtype relationship support between
reference types.

This does not include table instructions yet. This also does not include
wasm2js support.

Fixes #2444 and fixes #2447.

1 files changed, 11 insertions, 6 deletions

diff --git a/src/passes/Inlining.cpp b/src/passes/Inlining.cpp
index db1db5971..c43d41e7f 100644
--- a/src/passes/Inlining.cpp
+++ b/src/passes/Inlining.cpp
@@ -46,13 +46,13 @@ namespace wasm {
 
 // Useful into on a function, helping us decide if we can inline it
 struct FunctionInfo {
-  std::atomic<Index> calls;
+  std::atomic<Index> refs;
   Index size;
   std::atomic<bool> lightweight;
   bool usedGlobally; // in a table or export
 
   FunctionInfo() {
-    calls = 0;
+    refs = 0;
     size = 0;
     lightweight = true;
     usedGlobally = false;
@@ -75,7 +75,7 @@ struct FunctionInfo {
     // FIXME: move this check to be first in this function, since we should
     // return true if oneCallerInlineMaxSize is bigger than
     // flexibleInlineMaxSize (which it typically should be).
-    if (calls == 1 && !usedGlobally &&
+    if (refs == 1 && !usedGlobally &&
         size <= options.inlining.oneCallerInlineMaxSize) {
       return true;
     }
@@ -108,11 +108,16 @@ struct FunctionInfoScanner
   void visitCall(Call* curr) {
     // can't add a new element in parallel
     assert(infos->count(curr->target) > 0);
-    (*infos)[curr->target].calls++;
+    (*infos)[curr->target].refs++;
     // having a call is not lightweight
     (*infos)[getFunction()->name].lightweight = false;
   }
 
+  void visitRefFunc(RefFunc* curr) {
+    assert(infos->count(curr->func) > 0);
+    (*infos)[curr->func].refs++;
+  }
+
   void visitFunction(Function* curr) {
     (*infos)[curr->name].size = Measurer::measure(curr->body);
   }
@@ -374,7 +379,7 @@ struct Inlining : public Pass {
         doInlining(module, func.get(), action);
         inlinedUses[inlinedName]++;
         inlinedInto.insert(func.get());
-        assert(inlinedUses[inlinedName] <= infos[inlinedName].calls);
+        assert(inlinedUses[inlinedName] <= infos[inlinedName].refs);
       }
     }
     // anything we inlined into may now have non-unique label names, fix it up
@@ -388,7 +393,7 @@ struct Inlining : public Pass {
     module->removeFunctions([&](Function* func) {
       auto name = func->name;
       auto& info = infos[name];
-      return inlinedUses.count(name) && inlinedUses[name] == info.calls &&
+      return inlinedUses.count(name) && inlinedUses[name] == info.refs &&
              !info.usedGlobally;
     });
     // return whether we did any work