Dart VM: Simplify code generation for equality operators.

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2013, 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_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 435 matching lines @@
                                        const ICData& original_ic_data) {
   if (!compiler->is_optimizing()) {
     compiler->AddCurrentDescriptor(PcDescriptors::kDeopt,
                                    deopt_id,
                                    token_pos);
   }
   const int kNumberOfArguments = 2;
   const Array& kNoArgumentNames = Object::null_array();
   const int kNumArgumentsChecked = 2;
 
-  Label check_identity;
-  __ LoadObject(TMP, Object::null_object(), PP);
-  __ cmpq(Address(RSP, 0 * kWordSize), TMP);
-  __ j(EQUAL, &check_identity);
-  __ cmpq(Address(RSP, 1 * kWordSize), TMP);
-  __ j(EQUAL, &check_identity);
-
   ICData& equality_ic_data = ICData::ZoneHandle(original_ic_data.raw());
   if (compiler->is_optimizing() && FLAG_propagate_ic_data) {
     ASSERT(!original_ic_data.IsNull());
     if (original_ic_data.NumberOfChecks() == 0) {
       // IC call for reoptimization populates original ICData.
       equality_ic_data = original_ic_data.raw();
     } else {
       // Megamorphic call.
       equality_ic_data = original_ic_data.AsUnaryClassChecks();
     }
   } else {
     const Array& arguments_descriptor =
         Array::Handle(ArgumentsDescriptor::New(kNumberOfArguments,
                                                kNoArgumentNames));
     equality_ic_data = ICData::New(compiler->parsed_function().function(),
                                    Symbols::EqualOperator(),
                                    arguments_descriptor,
                                    deopt_id,
                                    kNumArgumentsChecked);
   }
   compiler->GenerateInstanceCall(deopt_id,
                                  token_pos,
                                  kNumberOfArguments,
                                  kNoArgumentNames,
                                  locs,
                                  equality_ic_data);
-  Label check_ne;
-  __ jmp(&check_ne);
-
-  __ Bind(&check_identity);
-  Label equality_done;
-  if (compiler->is_optimizing()) {
-    // No need to update IC data.
-    Label is_true;
-    __ popq(RAX);
-    __ popq(RDX);
-    __ cmpq(RAX, RDX);
-    __ j(EQUAL, &is_true);
-    __ LoadObject(RAX, Bool::Get(kind != Token::kEQ), PP);
-    __ jmp(&equality_done);
-    __ Bind(&is_true);
-    __ LoadObject(RAX, Bool::Get(kind == Token::kEQ), PP);
-    if (kind == Token::kNE) {
-      // Skip not-equal result conversion.
-      __ jmp(&equality_done);
-    }
-  } else {
-    // Call stub, load IC data in register. The stub will update ICData if
-    // necessary.
-    Register ic_data_reg = locs->temp(0).reg();
-    ASSERT(ic_data_reg == RBX);  // Stub depends on it.
-    __ LoadObject(ic_data_reg, equality_ic_data, PP);
-    compiler->GenerateCall(token_pos,
-                           &StubCode::EqualityWithNullArgLabel(),
-                           PcDescriptors::kRuntimeCall,
-                           locs);
-    __ Drop(2);
-  }
-  __ Bind(&check_ne);
   if (kind == Token::kNE) {
     Label true_label, done;
     // Negate the condition: true label returns false and vice versa.
     __ CompareObject(RAX, Bool::True(), PP);
     __ j(EQUAL, &true_label, Assembler::kNearJump);
     __ LoadObject(RAX, Bool::True(), PP);
     __ jmp(&done, Assembler::kNearJump);
     __ Bind(&true_label);
     __ LoadObject(RAX, Bool::False(), PP);
     __ Bind(&done);
   }
-  __ Bind(&equality_done);
 }
 
 
 static void LoadValueCid(FlowGraphCompiler* compiler,
                          Register value_cid_reg,
                          Register value_reg,
                          Label* value_is_smi = NULL) {
   Label done;
   if (value_is_smi == NULL) {
     __ LoadImmediate(value_cid_reg, Immediate(kSmiCid), PP);
@@ skipping 153 matching lines @@
                                        LocationSummary* locs,
                                        Token::Kind kind,
                                        BranchInstr* branch,
                                        const ICData& ic_data,
                                        intptr_t deopt_id,
                                        intptr_t token_pos) {
   ASSERT((kind == Token::kEQ) || (kind == Token::kNE));
   ASSERT(!ic_data.IsNull() && (ic_data.NumberOfChecks() > 0));
   Register left = locs->in(0).reg();
   Register right = locs->in(1).reg();
-
-  Label done, identity_compare, non_null_compare;
-  __ CompareObject(right, Object::null_object(), PP);
-  __ j(EQUAL, &identity_compare, Assembler::kNearJump);
-  __ CompareObject(left, Object::null_object(), PP);
-  __ j(NOT_EQUAL, &non_null_compare, Assembler::kNearJump);
-  // Comparison with NULL is "===".
-  __ Bind(&identity_compare);
-  __ cmpq(left, right);
-  Condition cond = TokenKindToSmiCondition(kind);
-  if (branch != NULL) {
-    branch->EmitBranchOnCondition(compiler, cond);
-  } else {
-    Register result = locs->out().reg();
-    Label load_true;
-    __ j(cond, &load_true, Assembler::kNearJump);
-    __ LoadObject(result, Bool::False(), PP);
-    __ jmp(&done);
-    __ Bind(&load_true);
-    __ LoadObject(result, Bool::True(), PP);
-  }
-  __ jmp(&done);
-  __ Bind(&non_null_compare);  // Receiver is not null.
   __ pushq(left);
   __ pushq(right);
   EmitEqualityAsPolymorphicCall(compiler, ic_data, locs, branch, kind,
                                 deopt_id, token_pos);
-  __ Bind(&done);
 }
 
 
 static Condition FlipCondition(Condition condition) {
   switch (condition) {
     case EQUAL:         return EQUAL;
     case NOT_EQUAL:     return NOT_EQUAL;
     case LESS:          return GREATER;
     case LESS_EQUAL:    return GREATER_EQUAL;
     case GREATER:       return LESS;
@@ skipping 4115 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64