(Redoing the change 6946) Progress toward inlined type checks for classes with type arguments: fact…

runtime/vm/stub_code_ia32.cc

Index: runtime/vm/stub_code_ia32.cc
===================================================================
--- runtime/vm/stub_code_ia32.cc	(revision 6973)
+++ runtime/vm/stub_code_ia32.cc	(working copy)
@@ -1733,7 +1733,9 @@
 // Check if an instance class is a subtype of class/interface using simple
 // superchain and interface array traversal. Does not take type parameters into
 // account.
-// EAX: instance (preserved)
+// Cannot handle Smi instances (must be tested beforehand).
+// EAX: instance (to be preserved).
+// ECX: class to test.
 // EDX: class/interface to test against (is class of instance a subtype of it).
 //      (preserved).
 // Result in EBX: 1 is subtype, 0 maybe not.
@@ -1741,17 +1743,7 @@
 void StubCode::GenerateIsRawSubTypeStub(Assembler* assembler) {
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
-  Label test_class, not_found, found, class_loaded_in_ECX, smi_value;
-  __ EnterFrame(0);
-  __ testl(EAX, Immediate(kSmiTagMask));
-  __ j(ZERO, &smi_value, Assembler::kNearJump);
-  __ movl(ECX, FieldAddress(EAX, Object::class_offset()));
-  __ jmp(&class_loaded_in_ECX, Assembler::kNearJump);
-  __ Bind(&smi_value);
-  __ movl(ECX, FieldAddress(CTX, Context::isolate_offset()));
-  __ movl(ECX, Address(ECX, Isolate::object_store_offset()));
-  __ movl(ECX, Address(ECX, ObjectStore::smi_class_offset()));
-  __ Bind(&class_loaded_in_ECX);
+  Label test_class, not_found, found;
 
   __ movzxb(EBX, FieldAddress(EDX, Class::is_interface_offset()));
   // Check if we are comparing against class or interface.
@@ -1769,7 +1761,6 @@
   Label array_loop;
   __ Bind(&array_loop);
   __ subl(EDI, Immediate(Smi::RawValue(1)));
-  // __ cmpl(EDI, Immediate(0));
   __ j(LESS, &not_found, Assembler::kNearJump);
   // EDI is Smi therefore TIMES_2 instead of TIMES_4.
   // Get type from array.
@@ -1781,12 +1772,10 @@
 
   __ Bind(&not_found);
   __ xorl(EBX, EBX);
-  __ LeaveFrame();
   __ ret();
 
   __ Bind(&found);
   __ movl(EBX, Immediate(1));
-  __ LeaveFrame();
   __ ret();
 
   __ Bind(&test_class);