Dart VM: Simplify code generation for equality operators.

runtime/vm/stub_code_x64.cc

Index: runtime/vm/stub_code_x64.cc
===================================================================
--- runtime/vm/stub_code_x64.cc	(revision 28079)
+++ runtime/vm/stub_code_x64.cc	(working copy)
@@ -2003,104 +2003,6 @@
 }
 
 
-// Implements equality operator when one of the arguments is null
-// (identity check) and updates ICData if necessary.
-// TOS + 0: return address
-// TOS + 1: right argument
-// TOS + 2: left argument
-// RBX: ICData.
-// RAX: result.
-// TODO(srdjan): Move to VM stubs once Boolean objects become VM objects.
-void StubCode::GenerateEqualityWithNullArgStub(Assembler* assembler) {
-  static const intptr_t kNumArgsTested = 2;
-#if defined(DEBUG)
-  { Label ok;
-    __ movq(RCX, FieldAddress(RBX, ICData::num_args_tested_offset()));
-    __ cmpq(RCX, Immediate(kNumArgsTested));
-    __ j(EQUAL, &ok, Assembler::kNearJump);
-    __ Stop("Incorrect ICData for equality");
-    __ Bind(&ok);
-  }
-#endif  // DEBUG
-  // Check IC data, update if needed.
-  // RBX: IC data object (preserved).
-  __ movq(R12, FieldAddress(RBX, ICData::ic_data_offset()));
-  // R12: ic_data_array with check entries: classes and target functions.
-  __ leaq(R12, FieldAddress(R12, Array::data_offset()));
-  // R12: points directly to the first ic data array element.
-
-  Label get_class_id_as_smi, no_match, loop, compute_result, found;
-  __ Bind(&loop);
-  // Check left.
-  __ movq(RAX, Address(RSP, 2 * kWordSize));
-  __ call(&get_class_id_as_smi);
-  __ movq(R13, Address(R12, 0 * kWordSize));
-  __ cmpq(RAX, R13);  // Class id match?
-  __ j(NOT_EQUAL, &no_match, Assembler::kNearJump);
-  // Check right.
-  __ movq(RAX, Address(RSP, 1 * kWordSize));
-  __ call(&get_class_id_as_smi);
-  __ movq(R13, Address(R12, 1 * kWordSize));
-  __ cmpq(RAX, R13);  // Class id match?
-  __ j(EQUAL, &found, Assembler::kNearJump);
-  __ Bind(&no_match);
-  // Next check group.
-  __ addq(R12, Immediate(
-      kWordSize * ICData::TestEntryLengthFor(kNumArgsTested)));
-  __ cmpq(R13, Immediate(Smi::RawValue(kIllegalCid)));  // Done?
-  __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
-  Label update_ic_data;
-  __ jmp(&update_ic_data);
-
-  __ Bind(&found);
-  const intptr_t count_offset =
-      ICData::CountIndexFor(kNumArgsTested) * kWordSize;
-  __ addq(Address(R12, count_offset), Immediate(Smi::RawValue(1)));
-  __ j(NO_OVERFLOW, &compute_result);
-  __ movq(Address(R12, count_offset),
-          Immediate(Smi::RawValue(Smi::kMaxValue)));
-
-  __ Bind(&compute_result);
-  Label true_label;
-  __ movq(RAX, Address(RSP, 1 * kWordSize));
-  __ cmpq(RAX, Address(RSP, 2 * kWordSize));
-  __ j(EQUAL, &true_label, Assembler::kNearJump);
-  __ LoadObject(RAX, Bool::False(), PP);
-  __ ret();
-  __ Bind(&true_label);
-  __ LoadObject(RAX, Bool::True(), PP);
-  __ ret();
-
-  __ Bind(&get_class_id_as_smi);
-  Label not_smi;
-  // Test if Smi -> load Smi class for comparison.
-  __ testq(RAX, Immediate(kSmiTagMask));
-  __ j(NOT_ZERO, &not_smi, Assembler::kNearJump);
-  __ movq(RAX, Immediate(Smi::RawValue(kSmiCid)));
-  __ ret();
-
-  __ Bind(&not_smi);
-  __ LoadClassId(RAX, RAX);
-  __ SmiTag(RAX);
-  __ ret();
-
-  __ Bind(&update_ic_data);
-
-  // RBX: ICData
-  __ movq(RAX, Address(RSP, 1 * kWordSize));
-  __ movq(R13, Address(RSP, 2 * kWordSize));
-  __ EnterStubFrameWithPP();
-  __ pushq(R13);  // arg 0
-  __ pushq(RAX);  // arg 1
-  __ PushObject(Symbols::EqualOperator(), PP);  // Target's name.
-  __ pushq(RBX);  // ICData
-  __ CallRuntime(kUpdateICDataTwoArgsRuntimeEntry, 4);
-  __ Drop(4);
-  __ LeaveFrameWithPP();
-
-  __ jmp(&compute_result, Assembler::kNearJump);
-}
-
 // Calls to the runtime to optimize the given function.
 // RDI: function to be reoptimized.
 // R10: argument descriptor (preserved).