[vm/patch_class] Remove obsolete "patch" bit from Class object.

This bit was made redundant when parsing was moved out of vm into
frontend.

Change-Id: Ia0c40e2420e58caffa3ad7ed390b9189706b6acb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/153385
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Aprelev <aam@google.com>

runtime/vm/class_finalizer.cc

@@ -1151,14 +1151,6 @@ void ClassFinalizer::FinalizeClass(const Class& cls) {
   }
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)
 
-  if (cls.is_patch()) {
-    // The fields and functions of a patch class are copied to the
-    // patched class after parsing. There is nothing to finalize.
-    ASSERT(Array::Handle(cls.functions()).Length() == 0);
-    ASSERT(Array::Handle(cls.fields()).Length() == 0);
-    cls.set_is_finalized();
-    return;
-  }
   // Ensure super class is finalized.
   const Class& super = Class::Handle(cls.SuperClass());
   if (!super.IsNull()) {
@@ -1426,7 +1418,7 @@ void ClassFinalizer::SortClasses() {
       continue;
     }
     cls = table->At(cid);
-    if (cls.is_patch() || !cls.is_declaration_loaded()) {
+    if (!cls.is_declaration_loaded()) {
       continue;
     }
     if (cls.SuperClass() == I->object_store()->object_class()) {

runtime/vm/compiler/backend/il.cc

@@ -202,7 +202,6 @@ void HierarchyInfo::BuildRangesFor(ClassTable* table,
     if (cid == kNullCid && !exclude_null) continue;
     cls = table->At(cid);
     if (!include_abstract && cls.is_abstract()) continue;
-    if (cls.is_patch()) continue;
     if (cls.IsTopLevel()) continue;
 
     // We are either interested in [CidRange]es of subclasses or subtypes.
@@ -310,7 +309,7 @@ void HierarchyInfo::BuildRangesForJIT(ClassTable* table,
         for (; j < current_cid; ++j) {
           if (table->HasValidClassAt(j)) {
             klass = table->At(j);
-            if (!klass.is_patch() && !klass.IsTopLevel()) {
+            if (!klass.IsTopLevel()) {
               // If we care about abstract classes also, we cannot skip over any
               // arbitrary abstract class, only those which are subtypes.
               if (include_abstract) {

runtime/vm/isolate_reload.cc

@@ -404,11 +404,6 @@ class BecomeMapTraits {
 };
 
 bool IsolateReloadContext::IsSameClass(const Class& a, const Class& b) {
-  if (a.is_patch() != b.is_patch()) {
-    // TODO(johnmccutchan): Should we just check the class kind bits?
-    return false;
-  }
-
   // TODO(turnidge): We need to look at generic type arguments for
   // synthetic mixin classes.  Their names are not necessarily unique
   // currently.

runtime/vm/object.cc

@@ -4757,10 +4757,6 @@ void Class::set_is_type_finalized() const {
                                           raw_ptr()->state_bits_));
 }
 
-void Class::set_is_patch() const {
-  set_state_bits(PatchBit::update(true, raw_ptr()->state_bits_));
-}
-
 void Class::set_is_synthesized_class() const {
   set_state_bits(SynthesizedClassBit::update(true, raw_ptr()->state_bits_));
 }
@@ -5440,10 +5436,9 @@ const char* Class::ToCString() const {
   NoSafepointScope no_safepoint;
   const Library& lib = Library::Handle(library());
   const char* library_name = lib.IsNull() ? "" : lib.ToCString();
-  const char* patch_prefix = is_patch() ? "Patch " : "";
   const char* class_name = String::Handle(Name()).ToCString();
-  return OS::SCreate(Thread::Current()->zone(), "%s %sClass: %s", library_name,
-                     patch_prefix, class_name);
+  return OS::SCreate(Thread::Current()->zone(), "%s Class: %s", library_name,
+                     class_name);
 }
 
 // Thomas Wang, Integer Hash Functions.

runtime/vm/object.h

@@ -1359,9 +1359,6 @@ class Class : public Object {
   }
   void set_is_type_finalized() const;
 
-  bool is_patch() const { return PatchBit::decode(raw_ptr()->state_bits_); }
-  void set_is_patch() const;
-
   bool is_synthesized_class() const {
     return SynthesizedClassBit::decode(raw_ptr()->state_bits_);
   }
@@ -1666,7 +1663,6 @@ class Class : public Object {
     kClassLoadingPos = kClassFinalizedPos + kClassFinalizedSize,  // = 4
     kClassLoadingSize = 2,
     kAbstractBit = kClassLoadingPos + kClassLoadingSize,  // = 6
-    kPatchBit,
     kSynthesizedClassBit,
     kMixinAppAliasBit,
     kMixinTypeAppliedBit,
@@ -1688,7 +1684,6 @@ class Class : public Object {
                                            kClassLoadingPos,
                                            kClassLoadingSize> {};
   class AbstractBit : public BitField<uint32_t, bool, kAbstractBit, 1> {};
-  class PatchBit : public BitField<uint32_t, bool, kPatchBit, 1> {};
   class SynthesizedClassBit
       : public BitField<uint32_t, bool, kSynthesizedClassBit, 1> {};
   class FieldsMarkedNullableBit

runtime/vm/object_service.cc

@@ -96,7 +96,7 @@ void Class::PrintJSONImpl(JSONStream* stream, bool ref) const {
   jsobj.AddProperty("const", is_const());
   jsobj.AddProperty("_finalized", is_finalized());
   jsobj.AddProperty("_implemented", is_implemented());
-  jsobj.AddProperty("_patch", is_patch());
+  jsobj.AddProperty("_patch", false);
   jsobj.AddProperty("_traceAllocations", TraceAllocation(isolate));
 
   const Class& superClass = Class::Handle(SuperClass());