Internalize strings in-place

src/ia32/macro-assembler-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_IA32
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 2546 matching lines @@
   mov(scratch2, FieldOperand(object2, HeapObject::kMapOffset));
   movzx_b(scratch1, FieldOperand(scratch1, Map::kInstanceTypeOffset));
   movzx_b(scratch2, FieldOperand(scratch2, Map::kInstanceTypeOffset));
 
   // Check that both are flat one-byte strings.
   const int kFlatOneByteStringMask =
       kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
   const int kFlatOneByteStringTag =
       kStringTag | kOneByteStringTag | kSeqStringTag;
   // Interleave bits from both instance types and compare them in one check.
-  DCHECK_EQ(0, kFlatOneByteStringMask & (kFlatOneByteStringMask << 3));
+  const int kShift = 8;
+  DCHECK_EQ(0, kFlatOneByteStringMask & (kFlatOneByteStringMask << kShift));
   and_(scratch1, kFlatOneByteStringMask);
   and_(scratch2, kFlatOneByteStringMask);
-  lea(scratch1, Operand(scratch1, scratch2, times_8, 0));
-  cmp(scratch1, kFlatOneByteStringTag | (kFlatOneByteStringTag << 3));
+  shl(scratch2, kShift);
+  or_(scratch1, scratch2);
+  cmp(scratch1, kFlatOneByteStringTag | (kFlatOneByteStringTag << kShift));
   j(not_equal, failure);
 }
 
 
 void MacroAssembler::JumpIfNotUniqueNameInstanceType(Operand operand,
                                                      Label* not_unique_name,
                                                      Label::Distance distance) {
   STATIC_ASSERT(kInternalizedTag == 0 && kStringTag == 0);
   Label succeed;
   test(operand, Immediate(kIsNotStringMask | kIsNotInternalizedMask));
@@ skipping 363 matching lines @@
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32