Remove RTTs (#4848)

RTTs were removed from the GC spec and if they are added back in in the future,
they will be heap types rather than value types as in our implementation.
Updating our implementation to have RTTs be heap types would have been more work
than deleting them for questionable benefit since we don't know how long it will
be before they are specced again.

1 files changed, 16 insertions, 63 deletions

diff --git a/src/wasm/wasm-stack.cpp b/src/wasm/wasm-stack.cpp
index 2fc06b176..c29384dad 100644
--- a/src/wasm/wasm-stack.cpp
+++ b/src/wasm/wasm-stack.cpp
@@ -2016,26 +2016,18 @@ void BinaryInstWriter::visitCallRef(CallRef* curr) {
 
 void BinaryInstWriter::visitRefTest(RefTest* curr) {
   o << int8_t(BinaryConsts::GCPrefix);
-  if (curr->rtt) {
-    o << U32LEB(BinaryConsts::RefTest);
-  } else {
-    o << U32LEB(BinaryConsts::RefTestStatic);
-    parent.writeIndexedHeapType(curr->intendedType);
-  }
+  o << U32LEB(BinaryConsts::RefTestStatic);
+  parent.writeIndexedHeapType(curr->intendedType);
 }
 
 void BinaryInstWriter::visitRefCast(RefCast* curr) {
   o << int8_t(BinaryConsts::GCPrefix);
-  if (curr->rtt) {
-    o << U32LEB(BinaryConsts::RefCast);
+  if (curr->safety == RefCast::Unsafe) {
+    o << U32LEB(BinaryConsts::RefCastNopStatic);
   } else {
-    if (curr->safety == RefCast::Unsafe) {
-      o << U32LEB(BinaryConsts::RefCastNopStatic);
-    } else {
-      o << U32LEB(BinaryConsts::RefCastStatic);
-    }
-    parent.writeIndexedHeapType(curr->intendedType);
+    o << U32LEB(BinaryConsts::RefCastStatic);
   }
+  parent.writeIndexedHeapType(curr->intendedType);
 }
 
 void BinaryInstWriter::visitBrOn(BrOn* curr) {
@@ -2048,19 +2040,11 @@ void BinaryInstWriter::visitBrOn(BrOn* curr) {
       break;
     case BrOnCast:
       o << int8_t(BinaryConsts::GCPrefix);
-      if (curr->rtt) {
-        o << U32LEB(BinaryConsts::BrOnCast);
-      } else {
-        o << U32LEB(BinaryConsts::BrOnCastStatic);
-      }
+      o << U32LEB(BinaryConsts::BrOnCastStatic);
       break;
     case BrOnCastFail:
       o << int8_t(BinaryConsts::GCPrefix);
-      if (curr->rtt) {
-        o << U32LEB(BinaryConsts::BrOnCastFail);
-      } else {
-        o << U32LEB(BinaryConsts::BrOnCastStaticFail);
-      }
+      o << U32LEB(BinaryConsts::BrOnCastStaticFail);
       break;
     case BrOnFunc:
       o << int8_t(BinaryConsts::GCPrefix) << U32LEB(BinaryConsts::BrOnFunc);
@@ -2084,36 +2068,17 @@ void BinaryInstWriter::visitBrOn(BrOn* curr) {
       WASM_UNREACHABLE("invalid br_on_*");
   }
   o << U32LEB(getBreakIndex(curr->name));
-  if ((curr->op == BrOnCast || curr->op == BrOnCastFail) && !curr->rtt) {
+  if (curr->op == BrOnCast || curr->op == BrOnCastFail) {
     parent.writeIndexedHeapType(curr->intendedType);
   }
 }
 
-void BinaryInstWriter::visitRttCanon(RttCanon* curr) {
-  o << int8_t(BinaryConsts::GCPrefix) << U32LEB(BinaryConsts::RttCanon);
-  parent.writeIndexedHeapType(curr->type.getRtt().heapType);
-}
-
-void BinaryInstWriter::visitRttSub(RttSub* curr) {
-  o << int8_t(BinaryConsts::GCPrefix);
-  o << U32LEB(curr->fresh ? BinaryConsts::RttFreshSub : BinaryConsts::RttSub);
-  parent.writeIndexedHeapType(curr->type.getRtt().heapType);
-}
-
 void BinaryInstWriter::visitStructNew(StructNew* curr) {
   o << int8_t(BinaryConsts::GCPrefix);
-  if (curr->rtt) {
-    if (curr->isWithDefault()) {
-      o << U32LEB(BinaryConsts::StructNewDefaultWithRtt);
-    } else {
-      o << U32LEB(BinaryConsts::StructNewWithRtt);
-    }
+  if (curr->isWithDefault()) {
+    o << U32LEB(BinaryConsts::StructNewDefault);
   } else {
-    if (curr->isWithDefault()) {
-      o << U32LEB(BinaryConsts::StructNewDefault);
-    } else {
-      o << U32LEB(BinaryConsts::StructNew);
-    }
+    o << U32LEB(BinaryConsts::StructNew);
   }
   parent.writeIndexedHeapType(curr->type.getHeapType());
 }
@@ -2142,29 +2107,17 @@ void BinaryInstWriter::visitStructSet(StructSet* curr) {
 
 void BinaryInstWriter::visitArrayNew(ArrayNew* curr) {
   o << int8_t(BinaryConsts::GCPrefix);
-  if (curr->rtt) {
-    if (curr->isWithDefault()) {
-      o << U32LEB(BinaryConsts::ArrayNewDefaultWithRtt);
-    } else {
-      o << U32LEB(BinaryConsts::ArrayNewWithRtt);
-    }
+  if (curr->isWithDefault()) {
+    o << U32LEB(BinaryConsts::ArrayNewDefault);
   } else {
-    if (curr->isWithDefault()) {
-      o << U32LEB(BinaryConsts::ArrayNewDefault);
-    } else {
-      o << U32LEB(BinaryConsts::ArrayNew);
-    }
+    o << U32LEB(BinaryConsts::ArrayNew);
   }
   parent.writeIndexedHeapType(curr->type.getHeapType());
 }
 
 void BinaryInstWriter::visitArrayInit(ArrayInit* curr) {
   o << int8_t(BinaryConsts::GCPrefix);
-  if (curr->rtt) {
-    o << U32LEB(BinaryConsts::ArrayInit);
-  } else {
-    o << U32LEB(BinaryConsts::ArrayInitStatic);
-  }
+  o << U32LEB(BinaryConsts::ArrayInitStatic);
   parent.writeIndexedHeapType(curr->type.getHeapType());
   o << U32LEB(curr->values.size());
 }