Factor out super-class and interface array subtype checks into a stub.

runtime/vm/code_generator_ia32.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/code_generator.h"
 
 #include "lib/error.h"
@@ skipping 1450 matching lines @@
   // function.
   if (dst_type.IsVoidType()) {
     return;
   }
 
   // A null object is always assignable and is returned as result.
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   Label done, runtime_call;
   __ cmpl(EAX, raw_null);
-  __ j(EQUAL, &done, Assembler::kNearJump);
+  __ j(EQUAL, &done);
 
   // Generate throw new TypeError() if the type is malformed.
   if (dst_type.IsMalformed()) {
     const Error& error = Error::Handle(dst_type.malformed_error());
     const String& error_message = String::ZoneHandle(
         String::NewSymbol(error.ToErrorCString()));
     __ PushObject(Object::ZoneHandle());  // Make room for the result.
     const Immediate location =
         Immediate(reinterpret_cast<int32_t>(Smi::New(token_index)));
     __ pushl(location);  // Push the source location.
@@ skipping 54 matching lines @@
         __ jmp(&done, Assembler::kNearJump);
       } else {
         // Failed assignable type check: call runtime to throw TypeError.
         __ jmp(&runtime_call, Assembler::kNearJump);
       }
       // Compare if the classes are equal.
       __ Bind(&compare_classes);
       // If dst_type is an interface, we can skip the class equality check,
       // because instances cannot be of an interface type.
       if (!dst_type_class.is_interface()) {
-        // Check if classes are equal.
-        __ movl(ECX, FieldAddress(EAX, Object::class_offset()));
-        TestClassAndJump(dst_type_class, &done);  // Uses ECX.
-        // Check superclasses using a loop (faster than runtime call).
-        Label loop_done, loop;
-        __ Bind(&loop);
-        // ECX: class.
-        __ movl(ECX, FieldAddress(ECX, Class::super_type_offset()));
-        // The supertype of Object is a null object.
-        __ cmpl(ECX, raw_null);
-        __ j(EQUAL, &loop_done, Assembler::kNearJump);
-        __ movl(ECX, FieldAddress(ECX, Type::type_class_offset()));
-        TestClassAndJump(dst_type_class, &done);  // Uses ECX.
-        __ jmp(&loop);
-        __ Bind(&loop_done);
+        __ LoadObject(EDX, dst_type_class);
+        __ cmpl(EDX, ECX);
+        __ j(EQUAL, &done, Assembler::kNearJump);
+        __ pushl(EAX);
+        __ call(&StubCode::IsSubTypeLabel());
+        __ movl(EDI, EAX);
+        __ popl(EAX);
+        __ cmpl(EDI, Immediate(1));
+        __ j(EQUAL, &done, Assembler::kNearJump);
+        // Otherwise fallthrough
       } else {
         // However, for specific core library interfaces, we can check for
         // specific core library classes.
         Error& malformed_error = Error::Handle();
         if (dst_type.IsBoolInterface()) {
           __ movl(ECX, FieldAddress(EAX, Object::class_offset()));
           const Class& bool_class = Class::ZoneHandle(
               Isolate::Current()->object_store()->bool_class());
           TestClassAndJump(bool_class, &done);
         } else if (dst_type.IsSubtypeOf(
@@ skipping 23 matching lines @@
           TestClassAndJump(two_byte_string_class, &done);
           const Class& four_byte_string_class = Class::ZoneHandle(
               Isolate::Current()->object_store()->four_byte_string_class());
           TestClassAndJump(four_byte_string_class, &done);
         } else if (dst_type.IsFunctionInterface()) {
           __ movl(ECX, FieldAddress(EAX, Object::class_offset()));
           __ movl(ECX, FieldAddress(ECX, Class::signature_function_offset()));
           __ cmpl(ECX, raw_null);
           __ j(NOT_EQUAL, &done, Assembler::kNearJump);
         } else {
-          // Check interfaces.
-          Label fall_through;
-          // Get interfaces array from class.
-          __ movl(EBX, FieldAddress(EAX, Object::class_offset()));
-          __ movl(EBX, FieldAddress(EBX, Class::interfaces_offset()));
-          __ cmpl(EBX, raw_null);
-          __ j(EQUAL, &fall_through, Assembler::kNearJump);
-          // Iterate over interfaces array and check if any of interfaces match.
-          __ movl(EDI, FieldAddress(EBX, Array::length_offset()));
-          // EDI: array index
-          // EBX: array
-          Label loop;
-          __ Bind(&loop);
-          __ subl(EDI, Immediate(Smi::RawValue(1)));
-          __ cmpl(EDI, Immediate(0));
-          __ j(LESS, &runtime_call, Assembler::kNearJump);
-          // EDI is Smi therefore TIMES_2 instead of TIMES_4.
-          // Get type from array.
-          __ movl(ECX, FieldAddress(EBX, EDI, TIMES_2, Array::data_offset()));
-          __ movl(ECX, FieldAddress(ECX, Type::type_class_offset()));
-          TestClassAndJump(dst_type_class, &done);  // Uses ECX.
-          __ jmp(&loop, Assembler::kNearJump);
-          // Fall through to runtime code.
-          __ Bind(&fall_through);
+          __ LoadObject(EDX, dst_type_class);
+          // EAX: Instance (preserve).
+          // EDX: test class
+          __ pushl(EAX);
+          __ call(&StubCode::IsSubTypeLabel());
+          __ movl(EDI, EAX);
+          __ popl(EAX);
+          __ cmpl(EDI, Immediate(1));
+          __ j(EQUAL, &done, Assembler::kNearJump);
+          // Otherwise fallthrough
         }
       }
     }
   } else {
     ASSERT(!dst_type.IsInstantiated());
     // Skip check if destination is a dynamic type.
     if (dst_type.IsTypeParameter()) {
       // EAX must be preserved!
       Label fall_through;
       GenerateInstantiatorTypeArguments(token_index);
       // Type arguments are on stack
       __ popl(EBX);
       // Check if dynamic.
       __ cmpl(EBX, raw_null);
       __ j(EQUAL, &done, Assembler::kNearJump);
 
       // For now handle only TypeArguments and bail out if InstantiatedTypeArgs.
       __ movl(EDX, FieldAddress(EBX, Object::class_offset()));
       __ CompareObject(EDX, Object::ZoneHandle(Object::type_arguments_class()));
       __ j(NOT_EQUAL, &fall_through, Assembler::kNearJump);
+      // EBX: Instance of TypeArguments.
       __ movl(EDX,
           FieldAddress(EBX, TypeArguments::type_at_offset(dst_type.Index())));
+      // EDX: concrete type of dst_type.
       __ CompareObject(EDX, Type::ZoneHandle(Type::DynamicType()));
       __ j(EQUAL,  &done, Assembler::kNearJump);
+      // Check if the type has type parameters, if not do the class comparison.
+      Label not_smi;
+      __ testl(EAX, Immediate(kSmiTagMask));  // Value is Smi?
+      __ j(NOT_ZERO, &not_smi, Assembler::kNearJump);
+      __ CompareObject(EDX, Type::ZoneHandle(Type::IntInterface()));
+      __ j(EQUAL,  &done, Assembler::kNearJump);
+      __ CompareObject(EDX, Type::ZoneHandle(Type::NumberInterface()));
+      __ j(EQUAL,  &done, Assembler::kNearJump);
+      __ Bind(&not_smi);
+      __ movl(EDX, FieldAddress(EDX, Type::type_class_offset()));
+      __ movl(ECX, FieldAddress(EDX, Class::type_parameters_offset()));
+      // Check that class of dst_type has no type parameters.
+      __ cmpl(ECX, raw_null);
+      __ j(NOT_EQUAL, &fall_through, Assembler::kNearJump);
+      // We have a non-parameterized class in EDX, compare with class of
+      // value in EAX.
+      __ pushl(EAX);
+      __ call(&StubCode::IsSubTypeLabel());
+      __ movl(EDI, EAX);
+      __ popl(EAX);
+      __ cmpl(EDI, Immediate(1));
+      __ j(EQUAL, &done, Assembler::kNearJump);
+      // Check superclasses.

[regis, 2012/03/28 02:22:45]

Is this comment left over?

[srdjan, 2012/03/28 15:42:15]

Removed.

       __ Bind(&fall_through);
     }
   }
   __ Bind(&runtime_call);
   __ PushObject(Object::ZoneHandle());  // Make room for the result.
   const Immediate location =
       Immediate(reinterpret_cast<int32_t>(Smi::New(token_index)));
   __ pushl(location);  // Push the source location.
   __ pushl(EAX);  // Push the source object.
   __ PushObject(dst_type);  // Push the type of the destination.
@@ skipping 1103 matching lines @@
   const Error& error = Error::Handle(
       Parser::FormatError(script, token_index, "Error", format, args));
   va_end(args);
   Isolate::Current()->long_jump_base()->Jump(1, error);
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32