Minor cleanup in assembly code.

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 1595 matching lines @@
         __ 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()) {
         __ LoadObject(EDX, dst_type_class);
         __ cmpl(EDX, ECX);
         __ j(EQUAL, &done, Assembler::kNearJump);
-        __ pushl(EAX);
+        // EAX, EDX are preserved in stub, result is in EBX.
         __ call(&StubCode::IsRawSubTypeLabel());
-        __ movl(EDI, EAX);
-        __ popl(EAX);
-        __ cmpl(EDI, Immediate(1));
+        // Result in EBX: 1 is raw subtype.
+        __ cmpl(EBX, 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());
@@ skipping 26 matching lines @@
           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 {
           __ LoadObject(EDX, dst_type_class);
-          // EAX: Instance (preserve).
-          // EDX: test class
-          __ pushl(EAX);
+          // EAX: Instance (preserved).
+          // EDX: test class (preserved).
           __ call(&StubCode::IsRawSubTypeLabel());
-          __ movl(EDI, EAX);
-          __ popl(EAX);
-          __ cmpl(EDI, Immediate(1));
+          // Result in EBX: 1 is raw subtype.
+          __ cmpl(EBX, 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!
@@ skipping 23 matching lines @@
       __ 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);
+      // value in EAX. EAX, EDX are preserved in stub.
       __ call(&StubCode::IsRawSubTypeLabel());
-      __ movl(EDI, EAX);
-      __ popl(EAX);
-      __ cmpl(EDI, Immediate(1));
+      // Result in EBX: 1 is raw subtype.
+      __ cmpl(EBX, Immediate(1));
       __ j(EQUAL, &done, Assembler::kNearJump);
       __ 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.
@@ skipping 1104 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