Change iftable to never be null

Simplifies code generation by removing a null check. The null case
is rare.

Ritzperf code size: 13107624 -> 13095336

Also addressed comments from previous CL.

Bug: 32577579

Test: test-art-host, run ritzperf both with CC

Change-Id: I2b31e800867112869d7f0643e16c08826296979e

23 files changed, 146 insertions, 122 deletions

diff --git a/compiler/elf_builder.h b/compiler/elf_builder.h
index 31a75294bc..7c02384ff2 100644
--- a/compiler/elf_builder.h
+++ b/compiler/elf_builder.h
@@ -879,7 +879,7 @@ class ElfBuilder FINAL {
     elf_header.e_ident[EI_MAG2]       = ELFMAG2;
     elf_header.e_ident[EI_MAG3]       = ELFMAG3;
     elf_header.e_ident[EI_CLASS]      = (sizeof(Elf_Addr) == sizeof(Elf32_Addr))
-                                         ? ELFCLASS32 : ELFCLASS64;;
+                                         ? ELFCLASS32 : ELFCLASS64;
     elf_header.e_ident[EI_DATA]       = ELFDATA2LSB;
     elf_header.e_ident[EI_VERSION]    = EV_CURRENT;
     elf_header.e_ident[EI_OSABI]      = ELFOSABI_LINUX;
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index c6363d1708..7c3a2c6b6e 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -6490,12 +6490,9 @@ void InstructionCodeGeneratorARM::VisitCheckCast(HCheckCast* instruction) {
                                         iftable_offset,
                                         maybe_temp2_loc,
                                         kWithoutReadBarrier);
-      // Null iftable means it is empty and will always fail the check.
-      __ CompareAndBranchIfZero(temp, type_check_slow_path->GetEntryLabel());
-
-      // Loop through the iftable and check if any class matches.
+      // Iftable is never null.
       __ ldr(maybe_temp2_loc.AsRegister<Register>(), Address(temp, array_length_offset));
-
+      // Loop through the iftable and check if any class matches.
       Label start_loop;
       __ Bind(&start_loop);
       __ CompareAndBranchIfZero(maybe_temp2_loc.AsRegister<Register>(),
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 4ab6065819..6ec9c910ec 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -3802,12 +3802,9 @@ void InstructionCodeGeneratorARM64::VisitCheckCast(HCheckCast* instruction) {
                                         iftable_offset,
                                         maybe_temp2_loc,
                                         kWithoutReadBarrier);
-      // Null iftable means it is empty and will always fail the check.
-      __ Cbz(temp, type_check_slow_path->GetEntryLabel());
-
-      // Loop through the iftable and check if any class matches.
+      // Iftable is never null.
       __ Ldr(WRegisterFrom(maybe_temp2_loc), HeapOperand(temp.W(), array_length_offset));
-
+      // Loop through the iftable and check if any class matches.
       vixl::aarch64::Label start_loop;
       __ Bind(&start_loop);
       __ Cbz(WRegisterFrom(maybe_temp2_loc), type_check_slow_path->GetEntryLabel());
diff --git a/compiler/optimizing/code_generator_arm_vixl.cc b/compiler/optimizing/code_generator_arm_vixl.cc
index e9827e8620..c3ea3c7db2 100644
--- a/compiler/optimizing/code_generator_arm_vixl.cc
+++ b/compiler/optimizing/code_generator_arm_vixl.cc
@@ -5156,11 +5156,14 @@ void InstructionCodeGeneratorARMVIXL::VisitInstanceOf(HInstanceOf* instruction)
     __ Cbz(obj, &zero);
   }
 
-  // /* HeapReference<Class> */ out = obj->klass_
-  GenerateReferenceLoadTwoRegisters(instruction, out_loc, obj_loc, class_offset, maybe_temp_loc);
-
   switch (type_check_kind) {
     case TypeCheckKind::kExactCheck: {
+      // /* HeapReference<Class> */ out = obj->klass_
+      GenerateReferenceLoadTwoRegisters(instruction,
+                                        out_loc,
+                                        obj_loc,
+                                        class_offset,
+                                        maybe_temp_loc);
       __ Cmp(out, cls);
       // Classes must be equal for the instanceof to succeed.
       __ B(ne, &zero);
@@ -5170,6 +5173,12 @@ void InstructionCodeGeneratorARMVIXL::VisitInstanceOf(HInstanceOf* instruction)
     }
 
     case TypeCheckKind::kAbstractClassCheck: {
+      // /* HeapReference<Class> */ out = obj->klass_
+      GenerateReferenceLoadTwoRegisters(instruction,
+                                        out_loc,
+                                        obj_loc,
+                                        class_offset,
+                                        maybe_temp_loc);
       // If the class is abstract, we eagerly fetch the super class of the
       // object to avoid doing a comparison we know will fail.
       vixl32::Label loop;
@@ -5188,6 +5197,12 @@ void InstructionCodeGeneratorARMVIXL::VisitInstanceOf(HInstanceOf* instruction)
     }
 
     case TypeCheckKind::kClassHierarchyCheck: {
+      // /* HeapReference<Class> */ out = obj->klass_
+      GenerateReferenceLoadTwoRegisters(instruction,
+                                        out_loc,
+                                        obj_loc,
+                                        class_offset,
+                                        maybe_temp_loc);
       // Walk over the class hierarchy to find a match.
       vixl32::Label loop, success;
       __ Bind(&loop);
@@ -5207,6 +5222,12 @@ void InstructionCodeGeneratorARMVIXL::VisitInstanceOf(HInstanceOf* instruction)
     }
 
     case TypeCheckKind::kArrayObjectCheck: {
+      // /* HeapReference<Class> */ out = obj->klass_
+      GenerateReferenceLoadTwoRegisters(instruction,
+                                        out_loc,
+                                        obj_loc,
+                                        class_offset,
+                                        maybe_temp_loc);
       // Do an exact check.
       vixl32::Label exact_check;
       __ Cmp(out, cls);
@@ -5226,6 +5247,12 @@ void InstructionCodeGeneratorARMVIXL::VisitInstanceOf(HInstanceOf* instruction)
     }
 
     case TypeCheckKind::kArrayCheck: {
+      // /* HeapReference<Class> */ out = obj->klass_
+      GenerateReferenceLoadTwoRegisters(instruction,
+                                        out_loc,
+                                        obj_loc,
+                                        class_offset,
+                                        maybe_temp_loc);
       __ Cmp(out, cls);
       DCHECK(locations->OnlyCallsOnSlowPath());
       slow_path = new (GetGraph()->GetArena()) TypeCheckSlowPathARMVIXL(instruction,
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 2451b8d247..7e4ad267c8 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -6849,24 +6849,24 @@ void InstructionCodeGeneratorX86::VisitCheckCast(HCheckCast* instruction) {
                                           temp_loc,
                                           iftable_offset,
                                           kWithoutReadBarrier);
-        // Null iftable means it is empty.
-        __ testl(temp, temp);
-        __ j(kZero, type_check_slow_path->GetEntryLabel());
-
-        // Loop through the iftable and check if any class matches.
+        // Iftable is never null.
         __ movl(maybe_temp2_loc.AsRegister<Register>(), Address(temp, array_length_offset));
-
+        // Loop through the iftable and check if any class matches.
         NearLabel start_loop;
         __ Bind(&start_loop);
-        __ cmpl(cls.AsRegister<Register>(), Address(temp, object_array_data_offset));
-        __ j(kEqual, &done);  // Return if same class.
-        // Go to next interface.
-        __ addl(temp, Immediate(2 * kHeapReferenceSize));
+        // Need to subtract first to handle the empty array case.
         __ subl(maybe_temp2_loc.AsRegister<Register>(), Immediate(2));
-        __ j(kNotZero, &start_loop);
+        __ j(kNegative, type_check_slow_path->GetEntryLabel());
+        // Go to next interface if the classes do not match.
+        __ cmpl(cls.AsRegister<Register>(),
+                CodeGeneratorX86::ArrayAddress(temp,
+                                               maybe_temp2_loc,
+                                               TIMES_4,
+                                               object_array_data_offset));
+        __ j(kNotEqual, &start_loop);
+      } else {
+        __ jmp(type_check_slow_path->GetEntryLabel());
       }
-
-      __ jmp(type_check_slow_path->GetEntryLabel());
       break;
     }
   }
@@ -7562,7 +7562,7 @@ class RIPFixup : public AssemblerFixup, public ArenaObject<kArenaAllocCodeGenera
     // The value to patch is the distance from the offset in the constant area
     // from the address computed by the HX86ComputeBaseMethodAddress instruction.
     int32_t constant_offset = codegen_->ConstantAreaStart() + offset_into_constant_area_;
-    int32_t relative_position = constant_offset - codegen_->GetMethodAddressOffset();;
+    int32_t relative_position = constant_offset - codegen_->GetMethodAddressOffset();
 
     // Patch in the right value.
     region.StoreUnaligned<int32_t>(pos - 4, relative_position);
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 2425a4c3cb..19b30192cd 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -6259,23 +6259,24 @@ void InstructionCodeGeneratorX86_64::VisitCheckCast(HCheckCast* instruction) {
                                           temp_loc,
                                           iftable_offset,
                                           kWithoutReadBarrier);
-        // Null iftable means it is empty.
-        __ testl(temp, temp);
-        __ j(kZero, type_check_slow_path->GetEntryLabel());
-
-        // Loop through the iftable and check if any class matches.
+        // Iftable is never null.
         __ movl(maybe_temp2_loc.AsRegister<CpuRegister>(), Address(temp, array_length_offset));
-
+        // Loop through the iftable and check if any class matches.
         NearLabel start_loop;
         __ Bind(&start_loop);
-        __ cmpl(cls.AsRegister<CpuRegister>(), Address(temp, object_array_data_offset));
-        __ j(kEqual, &done);  // Return if same class.
-        // Go to next interface.
-        __ addl(temp, Immediate(2 * kHeapReferenceSize));
+        // Need to subtract first to handle the empty array case.
         __ subl(maybe_temp2_loc.AsRegister<CpuRegister>(), Immediate(2));
-        __ j(kNotZero, &start_loop);
+        __ j(kNegative, type_check_slow_path->GetEntryLabel());
+        // Go to next interface if the classes do not match.
+        __ cmpl(cls.AsRegister<CpuRegister>(),
+                CodeGeneratorX86_64::ArrayAddress(temp,
+                                                  maybe_temp2_loc,
+                                                  TIMES_4,
+                                                  object_array_data_offset));
+        __ j(kNotEqual, &start_loop);  // Return if same class.
+      } else {
+        __ jmp(type_check_slow_path->GetEntryLabel());
       }
-      __ jmp(type_check_slow_path->GetEntryLabel());
       break;
   }
 
diff --git a/compiler/utils/arm/jni_macro_assembler_arm_vixl.cc b/compiler/utils/arm/jni_macro_assembler_arm_vixl.cc
index 8a9fd90c32..23b2774179 100644
--- a/compiler/utils/arm/jni_macro_assembler_arm_vixl.cc
+++ b/compiler/utils/arm/jni_macro_assembler_arm_vixl.cc
@@ -49,7 +49,7 @@ static dwarf::Reg DWARFReg(vixl32::SRegister reg) {
   return dwarf::Reg::ArmFp(static_cast<int>(reg.GetCode()));
 }
 
-static constexpr size_t kFramePointerSize = static_cast<size_t>(kArmPointerSize);;
+static constexpr size_t kFramePointerSize = static_cast<size_t>(kArmPointerSize);
 
 void ArmVIXLJNIMacroAssembler::BuildFrame(size_t frame_size,
                                           ManagedRegister method_reg,
diff --git a/oatdump/oatdump.cc b/oatdump/oatdump.cc
index 3d208b5d28..4c01c147c0 100644
--- a/oatdump/oatdump.cc
+++ b/oatdump/oatdump.cc
@@ -2783,7 +2783,7 @@ class IMTDumper {
 
     bool result = klass->GetImt(pointer_size) == object_class->GetImt(pointer_size);
 
-    if (klass->GetIfTable() == nullptr) {
+    if (klass->GetIfTable()->Count() == 0) {
       DCHECK(result);
     }
 
@@ -2889,25 +2889,23 @@ class IMTDumper {
     std::cerr << " Interfaces:" << std::endl;
     // Run through iftable, find methods that slot here, see if they fit.
     mirror::IfTable* if_table = klass->GetIfTable();
-    if (if_table != nullptr) {
-      for (size_t i = 0, num_interfaces = klass->GetIfTableCount(); i < num_interfaces; ++i) {
-        mirror::Class* iface = if_table->GetInterface(i);
-        std::string iface_name;
-        std::cerr << "  " << iface->GetDescriptor(&iface_name) << std::endl;
-
-        for (ArtMethod& iface_method : iface->GetVirtualMethods(pointer_size)) {
-          uint32_t class_hash, name_hash, signature_hash;
-          ImTable::GetImtHashComponents(&iface_method, &class_hash, &name_hash, &signature_hash);
-          uint32_t imt_slot = ImTable::GetImtIndex(&iface_method);
-          std::cerr << "    " << iface_method.PrettyMethod(true)
-              << " slot=" << imt_slot
-              << std::hex
-              << " class_hash=0x" << class_hash
-              << " name_hash=0x" << name_hash
-              << " signature_hash=0x" << signature_hash
-              << std::dec
-              << std::endl;
-        }
+    for (size_t i = 0, num_interfaces = klass->GetIfTableCount(); i < num_interfaces; ++i) {
+      mirror::Class* iface = if_table->GetInterface(i);
+      std::string iface_name;
+      std::cerr << "  " << iface->GetDescriptor(&iface_name) << std::endl;
+
+      for (ArtMethod& iface_method : iface->GetVirtualMethods(pointer_size)) {
+        uint32_t class_hash, name_hash, signature_hash;
+        ImTable::GetImtHashComponents(&iface_method, &class_hash, &name_hash, &signature_hash);
+        uint32_t imt_slot = ImTable::GetImtIndex(&iface_method);
+        std::cerr << "    " << iface_method.PrettyMethod(true)
+            << " slot=" << imt_slot
+            << std::hex
+            << " class_hash=0x" << class_hash
+            << " name_hash=0x" << name_hash
+            << " signature_hash=0x" << signature_hash
+            << std::dec
+            << std::endl;
       }
     }
   }
@@ -2972,18 +2970,16 @@ class IMTDumper {
         } else {
           // Run through iftable, find methods that slot here, see if they fit.
           mirror::IfTable* if_table = klass->GetIfTable();
-          if (if_table != nullptr) {
-            for (size_t i = 0, num_interfaces = klass->GetIfTableCount(); i < num_interfaces; ++i) {
-              mirror::Class* iface = if_table->GetInterface(i);
-              size_t num_methods = iface->NumDeclaredVirtualMethods();
-              if (num_methods > 0) {
-                for (ArtMethod& iface_method : iface->GetMethods(pointer_size)) {
-                  if (ImTable::GetImtIndex(&iface_method) == index) {
-                    std::string i_name = iface_method.PrettyMethod(true);
-                    if (StartsWith(i_name, method.c_str())) {
-                      std::cerr << "  Slot " << index << " (1)" << std::endl;
-                      std::cerr << "    " << p_name << " (" << i_name << ")" << std::endl;
-                    }
+          for (size_t i = 0, num_interfaces = klass->GetIfTableCount(); i < num_interfaces; ++i) {
+            mirror::Class* iface = if_table->GetInterface(i);
+            size_t num_methods = iface->NumDeclaredVirtualMethods();
+            if (num_methods > 0) {
+              for (ArtMethod& iface_method : iface->GetMethods(pointer_size)) {
+                if (ImTable::GetImtIndex(&iface_method) == index) {
+                  std::string i_name = iface_method.PrettyMethod(true);
+                  if (StartsWith(i_name, method.c_str())) {
+                    std::cerr << "  Slot " << index << " (1)" << std::endl;
+                    std::cerr << "    " << p_name << " (" << i_name << ")" << std::endl;
                   }
                 }
               }
diff --git a/patchoat/patchoat.cc b/patchoat/patchoat.cc
index 3c8c1a397c..5dc14574a1 100644
--- a/patchoat/patchoat.cc
+++ b/patchoat/patchoat.cc
@@ -762,16 +762,14 @@ void PatchOat::VisitObject(mirror::Object* object) {
     if (vtable != nullptr) {
       vtable->Fixup(RelocatedCopyOfFollowImages(vtable), pointer_size, native_visitor);
     }
-    auto* iftable = klass->GetIfTable();
-    if (iftable != nullptr) {
-      for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
-        if (iftable->GetMethodArrayCount(i) > 0) {
-          auto* method_array = iftable->GetMethodArray(i);
-          CHECK(method_array != nullptr);
-          method_array->Fixup(RelocatedCopyOfFollowImages(method_array),
-                              pointer_size,
-                              native_visitor);
-        }
+    mirror::IfTable* iftable = klass->GetIfTable();
+    for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
+      if (iftable->GetMethodArrayCount(i) > 0) {
+        auto* method_array = iftable->GetMethodArray(i);
+        CHECK(method_array != nullptr);
+        method_array->Fixup(RelocatedCopyOfFollowImages(method_array),
+                            pointer_size,
+                            native_visitor);
       }
     }
   } else if (object->GetClass() == mirror::Method::StaticClass() ||
diff --git a/runtime/arch/arm/entrypoints_init_arm.cc b/runtime/arch/arm/entrypoints_init_arm.cc
index 2a12f1d84a..de72d3a18f 100644
--- a/runtime/arch/arm/entrypoints_init_arm.cc
+++ b/runtime/arch/arm/entrypoints_init_arm.cc
@@ -86,7 +86,7 @@ void InitEntryPoints(JniEntryPoints* jpoints, QuickEntryPoints* qpoints) {
   DefaultInitEntryPoints(jpoints, qpoints);
 
   // Cast
-  qpoints->pInstanceofNonTrivial = artInstanceOfFromCode;;
+  qpoints->pInstanceofNonTrivial = artInstanceOfFromCode;
   qpoints->pCheckInstanceOf = art_quick_check_instance_of;
 
   // Math
diff --git a/runtime/class_linker-inl.h b/runtime/class_linker-inl.h
index 350855bdba..7359243fc2 100644
--- a/runtime/class_linker-inl.h
+++ b/runtime/class_linker-inl.h
@@ -69,7 +69,7 @@ inline mirror::String* ClassLinker::ResolveString(uint32_t string_idx, ArtMethod
   Thread::PoisonObjectPointersIfDebug();
   ObjPtr<mirror::Class> declaring_class = referrer->GetDeclaringClass();
   // MethodVerifier refuses methods with string_idx out of bounds.
-  DCHECK_LT(string_idx, declaring_class->GetDexFile().NumStringIds());;
+  DCHECK_LT(string_idx, declaring_class->GetDexFile().NumStringIds());
   ObjPtr<mirror::String> string =
         mirror::StringDexCachePair::Lookup(declaring_class->GetDexCacheStrings(),
                                            string_idx,
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index ac5e6aae31..65e46c2248 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -475,6 +475,9 @@ bool ClassLinker::InitWithoutImage(std::vector<std::unique_ptr<const DexFile>> b
   SetClassRoot(kJavaLangString, java_lang_String.Get());
   SetClassRoot(kJavaLangRefReference, java_lang_ref_Reference.Get());
 
+  // Fill in the empty iftable. Needs to be done after the kObjectArrayClass root is set.
+  java_lang_Object->SetIfTable(AllocIfTable(self, 0));
+
   // Setup the primitive type classes.
   SetClassRoot(kPrimitiveBoolean, CreatePrimitiveClass(self, Primitive::kPrimBoolean));
   SetClassRoot(kPrimitiveByte, CreatePrimitiveClass(self, Primitive::kPrimByte));
@@ -916,13 +919,11 @@ static void SanityCheckObjectsCallback(mirror::Object* obj, void* arg ATTRIBUTE_
         SanityCheckArtMethod(klass->GetEmbeddedVTableEntry(i, pointer_size), nullptr, image_spaces);
       }
     }
-    auto* iftable = klass->GetIfTable();
-    if (iftable != nullptr) {
-      for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
-        if (iftable->GetMethodArrayCount(i) > 0) {
-          SanityCheckArtMethodPointerArray(
-              iftable->GetMethodArray(i), nullptr, pointer_size, image_spaces);
-        }
+    mirror::IfTable* iftable = klass->GetIfTable();
+    for (int32_t i = 0; i < klass->GetIfTableCount(); ++i) {
+      if (iftable->GetMethodArrayCount(i) > 0) {
+        SanityCheckArtMethodPointerArray(
+            iftable->GetMethodArray(i), nullptr, pointer_size, image_spaces);
       }
     }
   }
@@ -3401,7 +3402,8 @@ void ClassLinker::FixupDexCaches(ArtMethod* resolution_method) {
 }
 
 mirror::Class* ClassLinker::CreatePrimitiveClass(Thread* self, Primitive::Type type) {
-  ObjPtr<mirror::Class> klass = AllocClass(self, mirror::Class::PrimitiveClassSize(image_pointer_size_));
+  ObjPtr<mirror::Class> klass =
+      AllocClass(self, mirror::Class::PrimitiveClassSize(image_pointer_size_));
   if (UNLIKELY(klass == nullptr)) {
     self->AssertPendingOOMException();
     return nullptr;
@@ -3419,10 +3421,12 @@ mirror::Class* ClassLinker::InitializePrimitiveClass(ObjPtr<mirror::Class> primi
   ObjectLock<mirror::Class> lock(self, h_class);
   h_class->SetAccessFlags(kAccPublic | kAccFinal | kAccAbstract);
   h_class->SetPrimitiveType(type);
+  h_class->SetIfTable(GetClassRoot(kJavaLangObject)->GetIfTable());
   mirror::Class::SetStatus(h_class, mirror::Class::kStatusInitialized, self);
   const char* descriptor = Primitive::Descriptor(type);
-  ObjPtr<mirror::Class> existing = InsertClass(descriptor, h_class.Get(),
-                                        ComputeModifiedUtf8Hash(descriptor));
+  ObjPtr<mirror::Class> existing = InsertClass(descriptor,
+                                               h_class.Get(),
+                                               ComputeModifiedUtf8Hash(descriptor));
   CHECK(existing == nullptr) << "InitPrimitiveClass(" << type << ") failed";
   return h_class.Get();
 }
@@ -4121,6 +4125,8 @@ mirror::Class* ClassLinker::CreateProxyClass(ScopedObjectAccessAlreadyRunnable&
   DCHECK_EQ(klass->GetPrimitiveType(), Primitive::kPrimNot);
   klass->SetName(soa.Decode<mirror::String>(name));
   klass->SetDexCache(GetClassRoot(kJavaLangReflectProxy)->GetDexCache());
+  // Object has an empty iftable, copy it for that reason.
+  klass->SetIfTable(GetClassRoot(kJavaLangObject)->GetIfTable());
   mirror::Class::SetStatus(klass, mirror::Class::kStatusIdx, self);
   std::string descriptor(GetDescriptorForProxy(klass.Get()));
   const size_t hash = ComputeModifiedUtf8Hash(descriptor.c_str());
@@ -6381,16 +6387,18 @@ static size_t FillIfTable(ObjPtr<mirror::IfTable> iftable,
 bool ClassLinker::SetupInterfaceLookupTable(Thread* self, Handle<mirror::Class> klass,
                                             Handle<mirror::ObjectArray<mirror::Class>> interfaces) {
   StackHandleScope<1> hs(self);
-  const size_t super_ifcount =
-      klass->HasSuperClass() ? klass->GetSuperClass()->GetIfTableCount() : 0U;
+  const bool has_superclass = klass->HasSuperClass();
+  const size_t super_ifcount = has_superclass ? klass->GetSuperClass()->GetIfTableCount() : 0U;
   const bool have_interfaces = interfaces.Get() != nullptr;
   const size_t num_interfaces =
       have_interfaces ? interfaces->GetLength() : klass->NumDirectInterfaces();
   if (num_interfaces == 0) {
     if (super_ifcount == 0) {
+      if (LIKELY(has_superclass)) {
+        klass->SetIfTable(klass->GetSuperClass()->GetIfTable());
+      }
       // Class implements no interfaces.
       DCHECK_EQ(klass->GetIfTableCount(), 0);
-      DCHECK(klass->GetIfTable() == nullptr);
       return true;
     }
     // Class implements same interfaces as parent, are any of these not marker interfaces?
@@ -6583,7 +6591,7 @@ void ClassLinker::FillImtFromSuperClass(Handle<mirror::Class> klass,
   } else {
     // No imt in the super class, need to reconstruct from the iftable.
     ObjPtr<mirror::IfTable> if_table = super_class->GetIfTable();
-    if (if_table != nullptr) {
+    if (if_table->Count() != 0) {
       // Ignore copied methods since we will handle these in LinkInterfaceMethods.
       FillIMTFromIfTable(if_table,
                          unimplemented_method,
diff --git a/runtime/class_linker_test.cc b/runtime/class_linker_test.cc
index ab2d9d0a95..44590ba327 100644
--- a/runtime/class_linker_test.cc
+++ b/runtime/class_linker_test.cc
@@ -101,7 +101,8 @@ class ClassLinkerTest : public CommonRuntimeTest {
     EXPECT_EQ(0U, primitive->NumDirectInterfaces());
     EXPECT_FALSE(primitive->HasVTable());
     EXPECT_EQ(0, primitive->GetIfTableCount());
-    EXPECT_TRUE(primitive->GetIfTable() == nullptr);
+    EXPECT_TRUE(primitive->GetIfTable() != nullptr);
+    EXPECT_EQ(primitive->GetIfTable()->Count(), 0u);
     EXPECT_EQ(kAccPublic | kAccFinal | kAccAbstract, primitive->GetAccessFlags());
   }
 
diff --git a/runtime/class_table.h b/runtime/class_table.h
index bc9eaf4c2d..558c144013 100644
--- a/runtime/class_table.h
+++ b/runtime/class_table.h
@@ -48,7 +48,7 @@ class ClassTable {
     uint32_t operator()(const GcRoot<mirror::Class>& root) const NO_THREAD_SAFETY_ANALYSIS;
     // Same class loader and descriptor.
     bool operator()(const GcRoot<mirror::Class>& a, const GcRoot<mirror::Class>& b) const
-        NO_THREAD_SAFETY_ANALYSIS;;
+        NO_THREAD_SAFETY_ANALYSIS;
     // Same descriptor.
     bool operator()(const GcRoot<mirror::Class>& a, const char* descriptor) const
         NO_THREAD_SAFETY_ANALYSIS;
diff --git a/runtime/gc/space/image_space.cc b/runtime/gc/space/image_space.cc
index 0b602e946a..6019540c9e 100644
--- a/runtime/gc/space/image_space.cc
+++ b/runtime/gc/space/image_space.cc
@@ -1002,7 +1002,7 @@ class ImageSpaceLoader {
         mirror::IfTable* iftable = as_klass->GetIfTable<kVerifyNone, kWithoutReadBarrier>();
         // Ensure iftable arrays are fixed up since we need GetMethodArray to return the valid
         // contents.
-        if (iftable != nullptr && IsInAppImage(iftable)) {
+        if (IsInAppImage(iftable)) {
           operator()(iftable);
           for (int32_t i = 0, count = iftable->Count(); i < count; ++i) {
             if (iftable->GetMethodArrayCount<kVerifyNone, kWithoutReadBarrier>(i) > 0) {
diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index cb775cd7a3..8c63a9e979 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -1020,7 +1020,7 @@ inline bool DoInvokePolymorphic(Thread* self,
   } else {
     DCHECK(!is_range);
     ArtField* field = method_handle->GetTargetField();
-    Primitive::Type field_type = field->GetTypeAsPrimitiveType();;
+    Primitive::Type field_type = field->GetTypeAsPrimitiveType();
 
     switch (handle_kind) {
       case kInstanceGet: {
diff --git a/runtime/interpreter/unstarted_runtime.cc b/runtime/interpreter/unstarted_runtime.cc
index 2257fd6395..a5b1038d5a 100644
--- a/runtime/interpreter/unstarted_runtime.cc
+++ b/runtime/interpreter/unstarted_runtime.cc
@@ -424,7 +424,7 @@ static std::unique_ptr<MemMap> FindAndExtractEntry(const std::string& jar_file,
 
   std::unique_ptr<ZipArchive> zip_archive(ZipArchive::Open(jar_file.c_str(), error_msg));
   if (zip_archive == nullptr) {
-    return nullptr;;
+    return nullptr;
   }
   std::unique_ptr<ZipEntry> zip_entry(zip_archive->Find(entry_name, error_msg));
   if (zip_entry == nullptr) {
diff --git a/runtime/jit/jit.cc b/runtime/jit/jit.cc
index 4c1006360b..23a5ddd071 100644
--- a/runtime/jit/jit.cc
+++ b/runtime/jit/jit.cc
@@ -114,7 +114,7 @@ JitOptions* JitOptions::CreateFromRuntimeArguments(const RuntimeArgumentMap& opt
   } else {
     jit_options->invoke_transition_weight_ = std::max(
         jit_options->warmup_threshold_ / Jit::kDefaultInvokeTransitionWeightRatio,
-        static_cast<size_t>(1));;
+        static_cast<size_t>(1));
   }
 
   return jit_options;
diff --git a/runtime/mirror/class-inl.h b/runtime/mirror/class-inl.h
index bbdb2af16a..9a6d60e0ad 100644
--- a/runtime/mirror/class-inl.h
+++ b/runtime/mirror/class-inl.h
@@ -526,18 +526,17 @@ inline ArtMethod* Class::FindVirtualMethodForVirtualOrInterface(ArtMethod* metho
 template<VerifyObjectFlags kVerifyFlags,
          ReadBarrierOption kReadBarrierOption>
 inline IfTable* Class::GetIfTable() {
-  return GetFieldObject<IfTable, kVerifyFlags, kReadBarrierOption>(IfTableOffset());
+  ObjPtr<IfTable> ret = GetFieldObject<IfTable, kVerifyFlags, kReadBarrierOption>(IfTableOffset());
+  DCHECK(ret != nullptr) << PrettyClass(this);
+  return ret.Ptr();
 }
 
 inline int32_t Class::GetIfTableCount() {
-  ObjPtr<IfTable> iftable = GetIfTable();
-  if (iftable == nullptr) {
-    return 0;
-  }
-  return iftable->Count();
+  return GetIfTable()->Count();
 }
 
 inline void Class::SetIfTable(ObjPtr<IfTable> new_iftable) {
+  DCHECK(new_iftable != nullptr) << PrettyClass(this);
   SetFieldObject<false>(IfTableOffset(), new_iftable);
 }
 
diff --git a/runtime/oat.h b/runtime/oat.h
index 3aef707dc3..8c84d42043 100644
--- a/runtime/oat.h
+++ b/runtime/oat.h
@@ -32,7 +32,7 @@ class InstructionSetFeatures;
 class PACKED(4) OatHeader {
  public:
   static constexpr uint8_t kOatMagic[] = { 'o', 'a', 't', '\n' };
-  static constexpr uint8_t kOatVersion[] = { '0', '9', '1', '\0' };
+  static constexpr uint8_t kOatVersion[] = { '0', '9', '2', '\0' };
 
   static constexpr const char* kImageLocationKey = "image-location";
   static constexpr const char* kDex2OatCmdLineKey = "dex2oat-cmdline";
diff --git a/test/530-checker-loops3/src/Main.java b/test/530-checker-loops3/src/Main.java
index 6b5c657294..209786a113 100644
--- a/test/530-checker-loops3/src/Main.java
+++ b/test/530-checker-loops3/src/Main.java
@@ -246,7 +246,7 @@ public class Main {
 
     oneConstantIndex(a, b);
     for (int i = 0; i < a.length; i++) {
-      expectEquals(2, a[i]);;
+      expectEquals(2, a[i]);
     }
     try {
       oneConstantIndex(a, b1);
@@ -256,7 +256,7 @@ public class Main {
 
     multipleConstantIndices(a, b);
     for (int i = 0; i < a.length; i++) {
-      expectEquals(6, a[i]);;
+      expectEquals(6, a[i]);
     }
     try {
       multipleConstantIndices(a, b1);
@@ -266,7 +266,7 @@ public class Main {
 
     oneInvariantIndex(a, b, 1);
     for (int i = 0; i < a.length; i++) {
-      expectEquals(2, a[i]);;
+      expectEquals(2, a[i]);
     }
     try {
       oneInvariantIndex(a, b1, 1);
@@ -276,7 +276,7 @@ public class Main {
 
     multipleInvariantIndices(a, b, 1);
     for (int i = 0; i < a.length; i++) {
-      expectEquals(6, a[i]);;
+      expectEquals(6, a[i]);
     }
     try {
       multipleInvariantIndices(a, b1, 1);
@@ -286,18 +286,18 @@ public class Main {
 
     oneUnitStride(a, b);
     for (int i = 0; i < a.length; i++) {
-      expectEquals(i + 1, a[i]);;
+      expectEquals(i + 1, a[i]);
     }
     try {
       oneUnitStride(a, b1);
       throw new Error("Should throw AIOOBE");
     } catch (ArrayIndexOutOfBoundsException e) {
-      expectEquals(100, a[0]);;
+      expectEquals(100, a[0]);
     }
 
     multipleUnitStrides(a, b);
     for (int i = 1; i < a.length - 1; i++) {
-      expectEquals(3 * i + 3, a[i]);;
+      expectEquals(3 * i + 3, a[i]);
     }
     try {
       multipleUnitStrides(a, b1);
@@ -308,7 +308,7 @@ public class Main {
     multipleUnitStridesConditional(a, b);
     for (int i = 2; i < a.length - 2; i++) {
       int e = 3 * i + 3 + (((i & 1) == 0) ? i + 2 : i);
-      expectEquals(e, a[i]);;
+      expectEquals(e, a[i]);
     }
     try {
       multipleUnitStridesConditional(a, b1);
diff --git a/test/586-checker-null-array-get/src/Main.java b/test/586-checker-null-array-get/src/Main.java
index e0782bc84d..0ea7d34043 100644
--- a/test/586-checker-null-array-get/src/Main.java
+++ b/test/586-checker-null-array-get/src/Main.java
@@ -100,7 +100,7 @@ public class Main {
   /// CHECK-DAG:                     Return [<<ArrayGet2>>]
   public static float test1() {
     Test1 test1 = getNullTest1();
-    Test2 test2 = getNullTest2();;
+    Test2 test2 = getNullTest2();
     int[] iarr = test1.iarr;
     float[] farr = test2.farr;
     iarr[0] = iarr[1];
diff --git a/test/611-checker-simplify-if/src/Main.java b/test/611-checker-simplify-if/src/Main.java
index 774f239df3..c1d75ec357 100644
--- a/test/611-checker-simplify-if/src/Main.java
+++ b/test/611-checker-simplify-if/src/Main.java
@@ -144,7 +144,7 @@ public class Main {
   /// CHECK-NOT:                          GreaterThanOrEqual
   /// CHECK-NOT:                          If
   public static void testGreaterCondition(String[] args) {
-    int a = 42;;
+    int a = 42;
     if (args.length == 42) {
       a = 34;
     } else {