Merge experimental/a64 to bleeding_edge.

src/a64/stub-cache-a64.cc

-// Copyright 2012 the V8 project authors. All rights reserved.
+// Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "v8.h"
 
-#if V8_TARGET_ARCH_ARM
+#if V8_TARGET_ARCH_A64
 
 #include "ic-inl.h"
 #include "codegen.h"
 #include "stub-cache.h"
 
 namespace v8 {
 namespace internal {
 
+
 #define __ ACCESS_MASM(masm)
 
 
-static void ProbeTable(Isolate* isolate,
-                       MacroAssembler* masm,
-                       Code::Flags flags,
-                       StubCache::Table table,
-                       Register receiver,
-                       Register name,
-                       // Number of the cache entry, not scaled.
-                       Register offset,
-                       Register scratch,
-                       Register scratch2,
-                       Register offset_scratch) {
-  ExternalReference key_offset(isolate->stub_cache()->key_reference(table));
-  ExternalReference value_offset(isolate->stub_cache()->value_reference(table));
-  ExternalReference map_offset(isolate->stub_cache()->map_reference(table));
-
-  uint32_t key_off_addr = reinterpret_cast<uint32_t>(key_offset.address());
-  uint32_t value_off_addr = reinterpret_cast<uint32_t>(value_offset.address());
-  uint32_t map_off_addr = reinterpret_cast<uint32_t>(map_offset.address());
-
-  // Check the relative positions of the address fields.
-  ASSERT(value_off_addr > key_off_addr);
-  ASSERT((value_off_addr - key_off_addr) % 4 == 0);
-  ASSERT((value_off_addr - key_off_addr) < (256 * 4));
-  ASSERT(map_off_addr > key_off_addr);
-  ASSERT((map_off_addr - key_off_addr) % 4 == 0);
-  ASSERT((map_off_addr - key_off_addr) < (256 * 4));
-
-  Label miss;
-  Register base_addr = scratch;
-  scratch = no_reg;
-
-  // Multiply by 3 because there are 3 fields per entry (name, code, map).
-  __ add(offset_scratch, offset, Operand(offset, LSL, 1));
-
-  // Calculate the base address of the entry.
-  __ mov(base_addr, Operand(key_offset));
-  __ add(base_addr, base_addr, Operand(offset_scratch, LSL, kPointerSizeLog2));
-
-  // Check that the key in the entry matches the name.
-  __ ldr(ip, MemOperand(base_addr, 0));
-  __ cmp(name, ip);
-  __ b(ne, &miss);
-
-  // Check the map matches.
-  __ ldr(ip, MemOperand(base_addr, map_off_addr - key_off_addr));
-  __ ldr(scratch2, FieldMemOperand(receiver, HeapObject::kMapOffset));
-  __ cmp(ip, scratch2);
-  __ b(ne, &miss);
-
-  // Get the code entry from the cache.
-  Register code = scratch2;
-  scratch2 = no_reg;
-  __ ldr(code, MemOperand(base_addr, value_off_addr - key_off_addr));
-
-  // Check that the flags match what we're looking for.
-  Register flags_reg = base_addr;
-  base_addr = no_reg;
-  __ ldr(flags_reg, FieldMemOperand(code, Code::kFlagsOffset));
-  // It's a nice optimization if this constant is encodable in the bic insn.
-
-  uint32_t mask = Code::kFlagsNotUsedInLookup;
-  ASSERT(__ ImmediateFitsAddrMode1Instruction(mask));
-  __ bic(flags_reg, flags_reg, Operand(mask));
-  __ cmp(flags_reg, Operand(flags));
-  __ b(ne, &miss);
-
-#ifdef DEBUG
-    if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {
-      __ jmp(&miss);
-    } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {
-      __ jmp(&miss);
-    }
-#endif
-
-  // Jump to the first instruction in the code stub.
-  __ add(pc, code, Operand(Code::kHeaderSize - kHeapObjectTag));
-
-  // Miss: fall through.
-  __ bind(&miss);
-}
-
-
 void StubCompiler::GenerateDictionaryNegativeLookup(MacroAssembler* masm,
                                                     Label* miss_label,
                                                     Register receiver,
                                                     Handle<Name> name,
                                                     Register scratch0,
                                                     Register scratch1) {
+  ASSERT(!AreAliased(receiver, scratch0, scratch1));
   ASSERT(name->IsUniqueName());
-  ASSERT(!receiver.is(scratch0));
   Counters* counters = masm->isolate()->counters();
   __ IncrementCounter(counters->negative_lookups(), 1, scratch0, scratch1);
   __ IncrementCounter(counters->negative_lookups_miss(), 1, scratch0, scratch1);
 
   Label done;
 
   const int kInterceptorOrAccessCheckNeededMask =
       (1 << Map::kHasNamedInterceptor) | (1 << Map::kIsAccessCheckNeeded);
 
   // Bail out if the receiver has a named interceptor or requires access checks.
   Register map = scratch1;
-  __ ldr(map, FieldMemOperand(receiver, HeapObject::kMapOffset));
-  __ ldrb(scratch0, FieldMemOperand(map, Map::kBitFieldOffset));
-  __ tst(scratch0, Operand(kInterceptorOrAccessCheckNeededMask));
-  __ b(ne, miss_label);
+  __ Ldr(map, FieldMemOperand(receiver, HeapObject::kMapOffset));
+  __ Ldrb(scratch0, FieldMemOperand(map, Map::kBitFieldOffset));
+  __ Tst(scratch0, kInterceptorOrAccessCheckNeededMask);
+  __ B(ne, miss_label);
 
   // Check that receiver is a JSObject.
-  __ ldrb(scratch0, FieldMemOperand(map, Map::kInstanceTypeOffset));
-  __ cmp(scratch0, Operand(FIRST_SPEC_OBJECT_TYPE));
-  __ b(lt, miss_label);
+  __ Ldrb(scratch0, FieldMemOperand(map, Map::kInstanceTypeOffset));
+  __ Cmp(scratch0, FIRST_SPEC_OBJECT_TYPE);
+  __ B(lt, miss_label);
 
   // Load properties array.
   Register properties = scratch0;
-  __ ldr(properties, FieldMemOperand(receiver, JSObject::kPropertiesOffset));
+  __ Ldr(properties, FieldMemOperand(receiver, JSObject::kPropertiesOffset));
   // Check that the properties array is a dictionary.
-  __ ldr(map, FieldMemOperand(properties, HeapObject::kMapOffset));
-  Register tmp = properties;
-  __ LoadRoot(tmp, Heap::kHashTableMapRootIndex);
-  __ cmp(map, tmp);
-  __ b(ne, miss_label);
-
-  // Restore the temporarily used register.
-  __ ldr(properties, FieldMemOperand(receiver, JSObject::kPropertiesOffset));
-
+  __ Ldr(map, FieldMemOperand(properties, HeapObject::kMapOffset));
+  __ JumpIfNotRoot(map, Heap::kHashTableMapRootIndex, miss_label);
 
   NameDictionaryLookupStub::GenerateNegativeLookup(masm,
-                                                   miss_label,
-                                                   &done,
-                                                   receiver,
-                                                   properties,
-                                                   name,
-                                                   scratch1);
-  __ bind(&done);
+                                                     miss_label,
+                                                     &done,
+                                                     receiver,
+                                                     properties,
+                                                     name,
+                                                     scratch1);
+  __ Bind(&done);
   __ DecrementCounter(counters->negative_lookups_miss(), 1, scratch0, scratch1);
 }
 
 
+// Probe primary or secondary table.
+// If the entry is found in the cache, the generated code jump to the first
+// instruction of the stub in the cache.
+// If there is a miss the code fall trough.
+//
+// 'receiver', 'name' and 'offset' registers are preserved on miss.
+static void ProbeTable(Isolate* isolate,
+                       MacroAssembler* masm,
+                       Code::Flags flags,
+                       StubCache::Table table,
+                       Register receiver,
+                       Register name,
+                       Register offset,
+                       Register scratch,
+                       Register scratch2,
+                       Register scratch3) {
+  // Some code below relies on the fact that the Entry struct contains
+  // 3 pointers (name, code, map).
+  STATIC_ASSERT(sizeof(StubCache::Entry) == (3 * kPointerSize));
+
+  ExternalReference key_offset(isolate->stub_cache()->key_reference(table));
+  ExternalReference value_offset(isolate->stub_cache()->value_reference(table));
+  ExternalReference map_offset(isolate->stub_cache()->map_reference(table));
+
+  uintptr_t key_off_addr = reinterpret_cast<uintptr_t>(key_offset.address());
+  uintptr_t value_off_addr =
+      reinterpret_cast<uintptr_t>(value_offset.address());
+  uintptr_t map_off_addr = reinterpret_cast<uintptr_t>(map_offset.address());
+
+  Label miss;
+
+  ASSERT(!AreAliased(name, offset, scratch, scratch2, scratch3));
+
+  // Multiply by 3 because there are 3 fields per entry.
+  __ Add(scratch3, offset, Operand(offset, LSL, 1));
+
+  // Calculate the base address of the entry.
+  __ Mov(scratch, Operand(key_offset));
+  __ Add(scratch, scratch, Operand(scratch3, LSL, kPointerSizeLog2));
+
+  // Check that the key in the entry matches the name.
+  __ Ldr(scratch2, MemOperand(scratch));
+  __ Cmp(name, scratch2);
+  __ B(ne, &miss);
+
+  // Check the map matches.
+  __ Ldr(scratch2, MemOperand(scratch, map_off_addr - key_off_addr));
+  __ Ldr(scratch3, FieldMemOperand(receiver, HeapObject::kMapOffset));
+  __ Cmp(scratch2, scratch3);
+  __ B(ne, &miss);
+
+  // Get the code entry from the cache.
+  __ Ldr(scratch, MemOperand(scratch, value_off_addr - key_off_addr));
+
+  // Check that the flags match what we're looking for.
+  __ Ldr(scratch2.W(), FieldMemOperand(scratch, Code::kFlagsOffset));
+  __ Bic(scratch2.W(), scratch2.W(), Code::kFlagsNotUsedInLookup);
+  __ Cmp(scratch2.W(), flags);
+  __ B(ne, &miss);
+
+#ifdef DEBUG
+  if (FLAG_test_secondary_stub_cache && table == StubCache::kPrimary) {
+    __ B(&miss);
+  } else if (FLAG_test_primary_stub_cache && table == StubCache::kSecondary) {
+    __ B(&miss);
+  }
+#endif
+
+  // Jump to the first instruction in the code stub.
+  __ Add(scratch, scratch, Code::kHeaderSize - kHeapObjectTag);
+  __ Br(scratch);
+
+  // Miss: fall through.
+  __ Bind(&miss);
+}
+
+
 void StubCache::GenerateProbe(MacroAssembler* masm,
                               Code::Flags flags,
                               Register receiver,
                               Register name,
                               Register scratch,
                               Register extra,
                               Register extra2,
                               Register extra3) {
   Isolate* isolate = masm->isolate();
   Label miss;
 
-  // Make sure that code is valid. The multiplying code relies on the
-  // entry size being 12.
-  ASSERT(sizeof(Entry) == 12);
-
   // Make sure the flags does not name a specific type.
   ASSERT(Code::ExtractTypeFromFlags(flags) == 0);
 
   // Make sure that there are no register conflicts.
-  ASSERT(!scratch.is(receiver));
-  ASSERT(!scratch.is(name));
-  ASSERT(!extra.is(receiver));
-  ASSERT(!extra.is(name));
-  ASSERT(!extra.is(scratch));
-  ASSERT(!extra2.is(receiver));
-  ASSERT(!extra2.is(name));
-  ASSERT(!extra2.is(scratch));
-  ASSERT(!extra2.is(extra));
+  ASSERT(!AreAliased(receiver, name, scratch, extra, extra2, extra3));
 
-  // Check scratch, extra and extra2 registers are valid.
-  ASSERT(!scratch.is(no_reg));
+  // Make sure extra and extra2 registers are valid.
   ASSERT(!extra.is(no_reg));
   ASSERT(!extra2.is(no_reg));
   ASSERT(!extra3.is(no_reg));
 
   Counters* counters = masm->isolate()->counters();
   __ IncrementCounter(counters->megamorphic_stub_cache_probes(), 1,
                       extra2, extra3);
 
   // Check that the receiver isn't a smi.
   __ JumpIfSmi(receiver, &miss);
 
-  // Get the map of the receiver and compute the hash.
-  __ ldr(scratch, FieldMemOperand(name, Name::kHashFieldOffset));
-  __ ldr(ip, FieldMemOperand(receiver, HeapObject::kMapOffset));
-  __ add(scratch, scratch, Operand(ip));
-  uint32_t mask = kPrimaryTableSize - 1;
-  // We shift out the last two bits because they are not part of the hash and
-  // they are always 01 for maps.
-  __ mov(scratch, Operand(scratch, LSR, kHeapObjectTagSize));
-  // Mask down the eor argument to the minimum to keep the immediate
-  // ARM-encodable.
-  __ eor(scratch, scratch, Operand((flags >> kHeapObjectTagSize) & mask));
-  // Prefer and_ to ubfx here because ubfx takes 2 cycles.
-  __ and_(scratch, scratch, Operand(mask));
+  // Compute the hash for primary table.
+  __ Ldr(scratch, FieldMemOperand(name, Name::kHashFieldOffset));
+  __ Ldr(extra, FieldMemOperand(receiver, HeapObject::kMapOffset));
+  __ Add(scratch, scratch, extra);
+  __ Eor(scratch, scratch, flags);
+  // We shift out the last two bits because they are not part of the hash.
+  __ Ubfx(scratch, scratch, kHeapObjectTagSize,
+          CountTrailingZeros(kPrimaryTableSize, 64));
 
   // Probe the primary table.
-  ProbeTable(isolate,
-             masm,
-             flags,
-             kPrimary,
-             receiver,
-             name,
-             scratch,
-             extra,
-             extra2,
-             extra3);
+  ProbeTable(isolate, masm, flags, kPrimary, receiver, name,
+      scratch, extra, extra2, extra3);
 
-  // Primary miss: Compute hash for secondary probe.
-  __ sub(scratch, scratch, Operand(name, LSR, kHeapObjectTagSize));
-  uint32_t mask2 = kSecondaryTableSize - 1;
-  __ add(scratch, scratch, Operand((flags >> kHeapObjectTagSize) & mask2));
-  __ and_(scratch, scratch, Operand(mask2));
+  // Primary miss: Compute hash for secondary table.
+  __ Sub(scratch, scratch, Operand(name, LSR, kHeapObjectTagSize));
+  __ Add(scratch, scratch, flags >> kHeapObjectTagSize);
+  __ And(scratch, scratch, kSecondaryTableSize - 1);
 
   // Probe the secondary table.
-  ProbeTable(isolate,
-             masm,
-             flags,
-             kSecondary,
-             receiver,
-             name,
-             scratch,
-             extra,
-             extra2,
-             extra3);
+  ProbeTable(isolate, masm, flags, kSecondary, receiver, name,
+      scratch, extra, extra2, extra3);
 
   // Cache miss: Fall-through and let caller handle the miss by
   // entering the runtime system.
-  __ bind(&miss);
+  __ Bind(&miss);
   __ IncrementCounter(counters->megamorphic_stub_cache_misses(), 1,
                       extra2, extra3);
 }
 
 
 void StubCompiler::GenerateLoadGlobalFunctionPrototype(MacroAssembler* masm,
                                                        int index,
                                                        Register prototype) {
   // Load the global or builtins object from the current context.
-  __ ldr(prototype,
-         MemOperand(cp, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
+  __ Ldr(prototype, GlobalObjectMemOperand());
   // Load the native context from the global or builtins object.
-  __ ldr(prototype,
+  __ Ldr(prototype,
          FieldMemOperand(prototype, GlobalObject::kNativeContextOffset));
   // Load the function from the native context.
-  __ ldr(prototype, MemOperand(prototype, Context::SlotOffset(index)));
-  // Load the initial map.  The global functions all have initial maps.
-  __ ldr(prototype,
+  __ Ldr(prototype, ContextMemOperand(prototype, index));
+  // Load the initial map. The global functions all have initial maps.
+  __ Ldr(prototype,
          FieldMemOperand(prototype, JSFunction::kPrototypeOrInitialMapOffset));
   // Load the prototype from the initial map.
-  __ ldr(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));
+  __ Ldr(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));
 }
 
 
 void StubCompiler::GenerateDirectLoadGlobalFunctionPrototype(
     MacroAssembler* masm,
     int index,
     Register prototype,
     Label* miss) {
   Isolate* isolate = masm->isolate();
   // Get the global function with the given index.
   Handle<JSFunction> function(
       JSFunction::cast(isolate->native_context()->get(index)));
 
   // Check we're still in the same context.
   Register scratch = prototype;
-  const int offset = Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX);
-  __ ldr(scratch, MemOperand(cp, offset));
-  __ ldr(scratch, FieldMemOperand(scratch, GlobalObject::kNativeContextOffset));
-  __ ldr(scratch, MemOperand(scratch, Context::SlotOffset(index)));
-  __ Move(ip, function);
-  __ cmp(ip, scratch);
-  __ b(ne, miss);
+  __ Ldr(scratch, GlobalObjectMemOperand());
+  __ Ldr(scratch, FieldMemOperand(scratch, GlobalObject::kNativeContextOffset));
+  __ Ldr(scratch, ContextMemOperand(scratch, index));
+  __ Cmp(scratch, Operand(function));
+  __ B(ne, miss);
 
   // Load its initial map. The global functions all have initial maps.
-  __ Move(prototype, Handle<Map>(function->initial_map()));
+  __ Mov(prototype, Operand(Handle<Map>(function->initial_map())));
   // Load the prototype from the initial map.
-  __ ldr(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));
+  __ Ldr(prototype, FieldMemOperand(prototype, Map::kPrototypeOffset));
 }
 
 
 void StubCompiler::GenerateFastPropertyLoad(MacroAssembler* masm,
                                             Register dst,
                                             Register src,
                                             bool inobject,
                                             int index,
                                             Representation representation) {
   ASSERT(!FLAG_track_double_fields || !representation.IsDouble());
-  int offset = index * kPointerSize;
-  if (!inobject) {
+  USE(representation);
+  if (inobject) {
+    int offset = index * kPointerSize;
+    __ Ldr(dst, FieldMemOperand(src, offset));
+  } else {
     // Calculate the offset into the properties array.
-    offset = offset + FixedArray::kHeaderSize;
-    __ ldr(dst, FieldMemOperand(src, JSObject::kPropertiesOffset));
-    src = dst;
+    int offset = index * kPointerSize + FixedArray::kHeaderSize;
+    __ Ldr(dst, FieldMemOperand(src, JSObject::kPropertiesOffset));
+    __ Ldr(dst, FieldMemOperand(dst, offset));
   }
-  __ ldr(dst, FieldMemOperand(src, offset));
 }
 
 
 void StubCompiler::GenerateLoadArrayLength(MacroAssembler* masm,
                                            Register receiver,
                                            Register scratch,
                                            Label* miss_label) {
+  ASSERT(!AreAliased(receiver, scratch));
+
   // Check that the receiver isn't a smi.
   __ JumpIfSmi(receiver, miss_label);
 
   // Check that the object is a JS array.
-  __ CompareObjectType(receiver, scratch, scratch, JS_ARRAY_TYPE);
-  __ b(ne, miss_label);
+  __ JumpIfNotObjectType(receiver, scratch, scratch, JS_ARRAY_TYPE,
+                         miss_label);
 
   // Load length directly from the JS array.
-  __ ldr(r0, FieldMemOperand(receiver, JSArray::kLengthOffset));
+  __ Ldr(x0, FieldMemOperand(receiver, JSArray::kLengthOffset));
   __ Ret();
 }
 
 
 // Generate code to check if an object is a string.  If the object is a
 // heap object, its map's instance type is left in the scratch1 register.
-// If this is not needed, scratch1 and scratch2 may be the same register.
 static void GenerateStringCheck(MacroAssembler* masm,
                                 Register receiver,
                                 Register scratch1,
-                                Register scratch2,
                                 Label* smi,
                                 Label* non_string_object) {
   // Check that the receiver isn't a smi.
   __ JumpIfSmi(receiver, smi);
 
-  // Check that the object is a string.
-  __ ldr(scratch1, FieldMemOperand(receiver, HeapObject::kMapOffset));
-  __ ldrb(scratch1, FieldMemOperand(scratch1, Map::kInstanceTypeOffset));
-  __ and_(scratch2, scratch1, Operand(kIsNotStringMask));
-  // The cast is to resolve the overload for the argument of 0x0.
-  __ cmp(scratch2, Operand(static_cast<int32_t>(kStringTag)));
-  __ b(ne, non_string_object);
+  // Get the object's instance type filed.
+  __ Ldr(scratch1, FieldMemOperand(receiver, HeapObject::kMapOffset));
+  __ Ldrb(scratch1, FieldMemOperand(scratch1, Map::kInstanceTypeOffset));
+  // Check if the "not string" bit is set.
+  __ Tbnz(scratch1, MaskToBit(kNotStringTag), non_string_object);
 }
 
 
 // Generate code to load the length from a string object and return the length.
 // If the receiver object is not a string or a wrapped string object the
 // execution continues at the miss label. The register containing the
-// receiver is potentially clobbered.
+// receiver is not clobbered if the receiver is not a string.
 void StubCompiler::GenerateLoadStringLength(MacroAssembler* masm,
                                             Register receiver,
                                             Register scratch1,
                                             Register scratch2,
                                             Label* miss) {
+  // Input registers can't alias because we don't want to clobber the
+  // receiver register if the object is not a string.
+  ASSERT(!AreAliased(receiver, scratch1, scratch2));
+
   Label check_wrapper;
 
   // Check if the object is a string leaving the instance type in the
   // scratch1 register.
-  GenerateStringCheck(masm, receiver, scratch1, scratch2, miss, &check_wrapper);
+  GenerateStringCheck(masm, receiver, scratch1, miss, &check_wrapper);
 
   // Load length directly from the string.
-  __ ldr(r0, FieldMemOperand(receiver, String::kLengthOffset));
+  __ Ldr(x0, FieldMemOperand(receiver, String::kLengthOffset));
   __ Ret();
 
   // Check if the object is a JSValue wrapper.
-  __ bind(&check_wrapper);
-  __ cmp(scratch1, Operand(JS_VALUE_TYPE));
-  __ b(ne, miss);
+  __ Bind(&check_wrapper);
+  __ Cmp(scratch1, Operand(JS_VALUE_TYPE));
+  __ B(ne, miss);
 
   // Unwrap the value and check if the wrapped value is a string.
-  __ ldr(scratch1, FieldMemOperand(receiver, JSValue::kValueOffset));
-  GenerateStringCheck(masm, scratch1, scratch2, scratch2, miss, miss);
-  __ ldr(r0, FieldMemOperand(scratch1, String::kLengthOffset));
+  __ Ldr(scratch1, FieldMemOperand(receiver, JSValue::kValueOffset));
+  GenerateStringCheck(masm, scratch1, scratch2, miss, miss);
+  __ Ldr(x0, FieldMemOperand(scratch1, String::kLengthOffset));
   __ Ret();
 }
 
 
 void StubCompiler::GenerateLoadFunctionPrototype(MacroAssembler* masm,
                                                  Register receiver,
                                                  Register scratch1,
                                                  Register scratch2,
                                                  Label* miss_label) {
   __ TryGetFunctionPrototype(receiver, scratch1, scratch2, miss_label);
-  __ mov(r0, scratch1);
+  // TryGetFunctionPrototype can't put the result directly in x0 because the
+  // 3 inputs registers can't alias and we call this function from
+  // LoadIC::GenerateFunctionPrototype, where receiver is x0. So we explicitly
+  // move the result in x0.
+  __ Mov(x0, scratch1);
   __ Ret();
 }
 
 
 // Generate code to check that a global property cell is empty. Create
 // the property cell at compilation time if no cell exists for the
 // property.
 void StubCompiler::GenerateCheckPropertyCell(MacroAssembler* masm,
                                              Handle<JSGlobalObject> global,
                                              Handle<Name> name,
                                              Register scratch,
                                              Label* miss) {
   Handle<Cell> cell = JSGlobalObject::EnsurePropertyCell(global, name);
   ASSERT(cell->value()->IsTheHole());
-  __ mov(scratch, Operand(cell));
-  __ ldr(scratch, FieldMemOperand(scratch, Cell::kValueOffset));
-  __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
-  __ cmp(scratch, ip);
-  __ b(ne, miss);
+  __ Mov(scratch, Operand(cell));
+  __ Ldr(scratch, FieldMemOperand(scratch, Cell::kValueOffset));
+  __ JumpIfNotRoot(scratch, Heap::kTheHoleValueRootIndex, miss);
 }
 
 
 void StoreStubCompiler::GenerateNegativeHolderLookup(
     MacroAssembler* masm,
     Handle<JSObject> holder,
     Register holder_reg,
     Handle<Name> name,
     Label* miss) {
   if (holder->IsJSGlobalObject()) {
     GenerateCheckPropertyCell(
         masm, Handle<JSGlobalObject>::cast(holder), name, scratch1(), miss);
   } else if (!holder->HasFastProperties() && !holder->IsJSGlobalProxy()) {
     GenerateDictionaryNegativeLookup(
         masm, miss, holder_reg, name, scratch1(), scratch2());
   }
 }
 
 
-// Generate StoreTransition code, value is passed in r0 register.
-// When leaving generated code after success, the receiver_reg and name_reg
-// may be clobbered.  Upon branch to miss_label, the receiver and name
-// registers have their original values.
+// Generate StoreTransition code, value is passed in x0 register.
+// When leaving generated code after success, the receiver_reg and storage_reg
+// may be clobbered. Upon branch to miss_label, the receiver and name registers
+// have their original values.
 void StoreStubCompiler::GenerateStoreTransition(MacroAssembler* masm,
                                                 Handle<JSObject> object,
                                                 LookupResult* lookup,
                                                 Handle<Map> transition,
                                                 Handle<Name> name,
                                                 Register receiver_reg,
                                                 Register storage_reg,
                                                 Register value_reg,
                                                 Register scratch1,
                                                 Register scratch2,
                                                 Register scratch3,
                                                 Label* miss_label,
                                                 Label* slow) {
-  // r0 : value
   Label exit;
 
+  ASSERT(!AreAliased(receiver_reg, storage_reg, value_reg,
+                     scratch1, scratch2, scratch3));
+
+  // We don't need scratch3.
+  scratch3 = NoReg;
+
   int descriptor = transition->LastAdded();
   DescriptorArray* descriptors = transition->instance_descriptors();
   PropertyDetails details = descriptors->GetDetails(descriptor);
   Representation representation = details.representation();
   ASSERT(!representation.IsNone());
 
   if (details.type() == CONSTANT) {
     Handle<Object> constant(descriptors->GetValue(descriptor), masm->isolate());
-    __ Move(scratch1, constant);
-    __ cmp(value_reg, scratch1);
-    __ b(ne, miss_label);
+    __ LoadObject(scratch1, constant);
+    __ Cmp(value_reg, scratch1);
+    __ B(ne, miss_label);
   } else if (FLAG_track_fields && representation.IsSmi()) {
     __ JumpIfNotSmi(value_reg, miss_label);
   } else if (FLAG_track_heap_object_fields && representation.IsHeapObject()) {
     __ JumpIfSmi(value_reg, miss_label);
   } else if (FLAG_track_double_fields && representation.IsDouble()) {
     Label do_store, heap_number;
-    __ LoadRoot(scratch3, Heap::kHeapNumberMapRootIndex);
-    __ AllocateHeapNumber(storage_reg, scratch1, scratch2, scratch3, slow);
+    __ AllocateHeapNumber(storage_reg, slow, scratch1, scratch2);
 
+    // TODO(jbramley): Is fp_scratch the most appropriate FP scratch register?
+    // It's only used in Fcmp, but it's not really safe to use it like this.
     __ JumpIfNotSmi(value_reg, &heap_number);
-    __ SmiUntag(scratch1, value_reg);
-    __ vmov(s0, scratch1);
-    __ vcvt_f64_s32(d0, s0);
-    __ jmp(&do_store);
+    __ SmiUntagToDouble(fp_scratch, value_reg);
+    __ B(&do_store);
 
-    __ bind(&heap_number);
+    __ Bind(&heap_number);
     __ CheckMap(value_reg, scratch1, Heap::kHeapNumberMapRootIndex,
                 miss_label, DONT_DO_SMI_CHECK);
-    __ vldr(d0, FieldMemOperand(value_reg, HeapNumber::kValueOffset));
+    __ Ldr(fp_scratch, FieldMemOperand(value_reg, HeapNumber::kValueOffset));
 
-    __ bind(&do_store);
-    __ vstr(d0, FieldMemOperand(storage_reg, HeapNumber::kValueOffset));
+    __ Bind(&do_store);
+    __ Str(fp_scratch, FieldMemOperand(storage_reg, HeapNumber::kValueOffset));
   }
 
-  // Stub never generated for non-global objects that require access
-  // checks.
+  // Stub never generated for non-global objects that require access checks.
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
-  if (details.type() == FIELD &&
-      object->map()->unused_property_fields() == 0) {
+  if ((details.type() == FIELD) &&
+      (object->map()->unused_property_fields() == 0)) {
     // The properties must be extended before we can store the value.
     // We jump to a runtime call that extends the properties array.
-    __ push(receiver_reg);
-    __ mov(r2, Operand(transition));
-    __ Push(r2, r0);
+    __ Mov(scratch1, Operand(transition));
+    __ Push(receiver_reg, scratch1, value_reg);
     __ TailCallExternalReference(
         ExternalReference(IC_Utility(IC::kSharedStoreIC_ExtendStorage),
                           masm->isolate()),
         3,
         1);
     return;
   }
 
   // Update the map of the object.
-  __ mov(scratch1, Operand(transition));
-  __ str(scratch1, FieldMemOperand(receiver_reg, HeapObject::kMapOffset));
+  __ Mov(scratch1, Operand(transition));
+  __ Str(scratch1, FieldMemOperand(receiver_reg, HeapObject::kMapOffset));
 
   // Update the write barrier for the map field.
   __ RecordWriteField(receiver_reg,
                       HeapObject::kMapOffset,
                       scratch1,
                       scratch2,
                       kLRHasNotBeenSaved,
                       kDontSaveFPRegs,
                       OMIT_REMEMBERED_SET,
                       OMIT_SMI_CHECK);
 
   if (details.type() == CONSTANT) {
-    ASSERT(value_reg.is(r0));
+    ASSERT(value_reg.is(x0));
     __ Ret();
     return;
   }
 
   int index = transition->instance_descriptors()->GetFieldIndex(
       transition->LastAdded());
 
   // Adjust for the number of properties stored in the object. Even in the
   // face of a transition we can use the old map here because the size of the
   // object and the number of in-object properties is not going to change.
   index -= object->map()->inobject_properties();
 
   // TODO(verwaest): Share this code as a code stub.
   SmiCheck smi_check = representation.IsTagged()
       ? INLINE_SMI_CHECK : OMIT_SMI_CHECK;
   if (index < 0) {
     // Set the property straight into the object.
     int offset = object->map()->instance_size() + (index * kPointerSize);
+    // TODO(jbramley): This construct appears in several places in this
+    // function. Try to clean it up, perhaps using a result_reg.
     if (FLAG_track_double_fields && representation.IsDouble()) {
-      __ str(storage_reg, FieldMemOperand(receiver_reg, offset));
+      __ Str(storage_reg, FieldMemOperand(receiver_reg, offset));
     } else {
-      __ str(value_reg, FieldMemOperand(receiver_reg, offset));
+      __ Str(value_reg, FieldMemOperand(receiver_reg, offset));
     }
 
     if (!FLAG_track_fields || !representation.IsSmi()) {
       // Update the write barrier for the array address.
       if (!FLAG_track_double_fields || !representation.IsDouble()) {
-        __ mov(storage_reg, value_reg);
+        __ Mov(storage_reg, value_reg);
       }
       __ RecordWriteField(receiver_reg,
                           offset,
                           storage_reg,
                           scratch1,
                           kLRHasNotBeenSaved,
                           kDontSaveFPRegs,
                           EMIT_REMEMBERED_SET,
                           smi_check);
     }
   } else {
     // Write to the properties array.
     int offset = index * kPointerSize + FixedArray::kHeaderSize;
     // Get the properties array
-    __ ldr(scratch1,
+    __ Ldr(scratch1,
            FieldMemOperand(receiver_reg, JSObject::kPropertiesOffset));
     if (FLAG_track_double_fields && representation.IsDouble()) {
-      __ str(storage_reg, FieldMemOperand(scratch1, offset));
+      __ Str(storage_reg, FieldMemOperand(scratch1, offset));
     } else {
-      __ str(value_reg, FieldMemOperand(scratch1, offset));
+      __ Str(value_reg, FieldMemOperand(scratch1, offset));
     }
 
     if (!FLAG_track_fields || !representation.IsSmi()) {
       // Update the write barrier for the array address.
       if (!FLAG_track_double_fields || !representation.IsDouble()) {
-        __ mov(storage_reg, value_reg);
+        __ Mov(storage_reg, value_reg);
       }
       __ RecordWriteField(scratch1,
                           offset,
                           storage_reg,
                           receiver_reg,
                           kLRHasNotBeenSaved,
                           kDontSaveFPRegs,
                           EMIT_REMEMBERED_SET,
                           smi_check);
     }
   }
 
-  // Return the value (register r0).
-  ASSERT(value_reg.is(r0));
-  __ bind(&exit);
+  __ Bind(&exit);
+  // Return the value (register x0).
+  ASSERT(value_reg.is(x0));
   __ Ret();
 }
 
 
-// Generate StoreField code, value is passed in r0 register.
-// When leaving generated code after success, the receiver_reg and name_reg
-// may be clobbered.  Upon branch to miss_label, the receiver and name
-// registers have their original values.
+// Generate StoreField code, value is passed in x0 register.
+// When leaving generated code after success, the receiver_reg and name_reg may
+// be clobbered. Upon branch to miss_label, the receiver and name registers have
+// their original values.
 void StoreStubCompiler::GenerateStoreField(MacroAssembler* masm,
                                            Handle<JSObject> object,
                                            LookupResult* lookup,
                                            Register receiver_reg,
                                            Register name_reg,
                                            Register value_reg,
                                            Register scratch1,
                                            Register scratch2,
                                            Label* miss_label) {
-  // r0 : value
+  // x0 : value
   Label exit;
 
   // Stub never generated for non-global objects that require access
   // checks.
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   int index = lookup->GetFieldIndex().field_index();
 
   // Adjust for the number of properties stored in the object. Even in the
   // face of a transition we can use the old map here because the size of the
   // object and the number of in-object properties is not going to change.
   index -= object->map()->inobject_properties();
 
   Representation representation = lookup->representation();
   ASSERT(!representation.IsNone());
   if (FLAG_track_fields && representation.IsSmi()) {
     __ JumpIfNotSmi(value_reg, miss_label);
   } else if (FLAG_track_heap_object_fields && representation.IsHeapObject()) {
     __ JumpIfSmi(value_reg, miss_label);
   } else if (FLAG_track_double_fields && representation.IsDouble()) {
     // Load the double storage.
     if (index < 0) {
-      int offset = object->map()->instance_size() + (index * kPointerSize);
-      __ ldr(scratch1, FieldMemOperand(receiver_reg, offset));
+      int offset = (index * kPointerSize) + object->map()->instance_size();
+      __ Ldr(scratch1, FieldMemOperand(receiver_reg, offset));
     } else {
-      __ ldr(scratch1,
+      int offset = (index * kPointerSize) + FixedArray::kHeaderSize;
+      __ Ldr(scratch1,
              FieldMemOperand(receiver_reg, JSObject::kPropertiesOffset));
-      int offset = index * kPointerSize + FixedArray::kHeaderSize;
-      __ ldr(scratch1, FieldMemOperand(scratch1, offset));
+      __ Ldr(scratch1, FieldMemOperand(scratch1, offset));
     }
 
     // Store the value into the storage.
     Label do_store, heap_number;
+    // TODO(jbramley): Is fp_scratch the most appropriate FP scratch register?
+    // It's only used in Fcmp, but it's not really safe to use it like this.
     __ JumpIfNotSmi(value_reg, &heap_number);
-    __ SmiUntag(scratch2, value_reg);
-    __ vmov(s0, scratch2);
-    __ vcvt_f64_s32(d0, s0);
-    __ jmp(&do_store);
+    __ SmiUntagToDouble(fp_scratch, value_reg);
+    __ B(&do_store);
 
-    __ bind(&heap_number);
+    __ Bind(&heap_number);
     __ CheckMap(value_reg, scratch2, Heap::kHeapNumberMapRootIndex,
                 miss_label, DONT_DO_SMI_CHECK);
-    __ vldr(d0, FieldMemOperand(value_reg, HeapNumber::kValueOffset));
+    __ Ldr(fp_scratch, FieldMemOperand(value_reg, HeapNumber::kValueOffset));
 
-    __ bind(&do_store);
-    __ vstr(d0, FieldMemOperand(scratch1, HeapNumber::kValueOffset));
-    // Return the value (register r0).
-    ASSERT(value_reg.is(r0));
+    __ Bind(&do_store);
+    __ Str(fp_scratch, FieldMemOperand(scratch1, HeapNumber::kValueOffset));
+
+    // Return the value (register x0).
+    ASSERT(value_reg.is(x0));
     __ Ret();
     return;
   }
 
   // TODO(verwaest): Share this code as a code stub.
   SmiCheck smi_check = representation.IsTagged()
       ? INLINE_SMI_CHECK : OMIT_SMI_CHECK;
   if (index < 0) {
     // Set the property straight into the object.
     int offset = object->map()->instance_size() + (index * kPointerSize);
-    __ str(value_reg, FieldMemOperand(receiver_reg, offset));
+    __ Str(value_reg, FieldMemOperand(receiver_reg, offset));
 
     if (!FLAG_track_fields || !representation.IsSmi()) {
       // Skip updating write barrier if storing a smi.
       __ JumpIfSmi(value_reg, &exit);
 
       // Update the write barrier for the array address.
       // Pass the now unused name_reg as a scratch register.
-      __ mov(name_reg, value_reg);
+      __ Mov(name_reg, value_reg);
       __ RecordWriteField(receiver_reg,
                           offset,
                           name_reg,
                           scratch1,
                           kLRHasNotBeenSaved,
                           kDontSaveFPRegs,
                           EMIT_REMEMBERED_SET,
                           smi_check);
     }
   } else {
     // Write to the properties array.
     int offset = index * kPointerSize + FixedArray::kHeaderSize;
     // Get the properties array
-    __ ldr(scratch1,
+    __ Ldr(scratch1,
            FieldMemOperand(receiver_reg, JSObject::kPropertiesOffset));
-    __ str(value_reg, FieldMemOperand(scratch1, offset));
+    __ Str(value_reg, FieldMemOperand(scratch1, offset));
 
     if (!FLAG_track_fields || !representation.IsSmi()) {
       // Skip updating write barrier if storing a smi.
       __ JumpIfSmi(value_reg, &exit);
 
       // Update the write barrier for the array address.
       // Ok to clobber receiver_reg and name_reg, since we return.
-      __ mov(name_reg, value_reg);
+      __ Mov(name_reg, value_reg);
       __ RecordWriteField(scratch1,
                           offset,
                           name_reg,
                           receiver_reg,
                           kLRHasNotBeenSaved,
                           kDontSaveFPRegs,
                           EMIT_REMEMBERED_SET,
                           smi_check);
     }
   }
 
-  // Return the value (register r0).
-  ASSERT(value_reg.is(r0));
-  __ bind(&exit);
+  __ Bind(&exit);
+  // Return the value (register x0).
+  ASSERT(value_reg.is(x0));
   __ Ret();
 }
 
 
 void StoreStubCompiler::GenerateRestoreName(MacroAssembler* masm,
                                             Label* label,
                                             Handle<Name> name) {
   if (!label->is_unused()) {
-    __ bind(label);
-    __ mov(this->name(), Operand(name));
+    __ Bind(label);
+    __ Mov(this->name(), Operand(name));
   }
 }
 
 
 static void PushInterceptorArguments(MacroAssembler* masm,
                                      Register receiver,
                                      Register holder,
                                      Register name,
                                      Handle<JSObject> holder_obj) {
   STATIC_ASSERT(StubCache::kInterceptorArgsNameIndex == 0);
   STATIC_ASSERT(StubCache::kInterceptorArgsInfoIndex == 1);
   STATIC_ASSERT(StubCache::kInterceptorArgsThisIndex == 2);
   STATIC_ASSERT(StubCache::kInterceptorArgsHolderIndex == 3);
   STATIC_ASSERT(StubCache::kInterceptorArgsLength == 4);
-  __ push(name);
+
+  __ Push(name);
   Handle<InterceptorInfo> interceptor(holder_obj->GetNamedInterceptor());
   ASSERT(!masm->isolate()->heap()->InNewSpace(*interceptor));
   Register scratch = name;
-  __ mov(scratch, Operand(interceptor));
-  __ push(scratch);
-  __ push(receiver);
-  __ push(holder);
+  __ Mov(scratch, Operand(interceptor));
+  __ Push(scratch, receiver, holder);
 }
 
 
 static void CompileCallLoadPropertyWithInterceptor(
     MacroAssembler* masm,
     Register receiver,
     Register holder,
     Register name,
     Handle<JSObject> holder_obj,
     IC::UtilityId id) {
   PushInterceptorArguments(masm, receiver, holder, name, holder_obj);
+
   __ CallExternalReference(
       ExternalReference(IC_Utility(id), masm->isolate()),
       StubCache::kInterceptorArgsLength);
 }
 
 
 // Generate call to api function.
 static void GenerateFastApiCall(MacroAssembler* masm,
                                 const CallOptimization& optimization,
                                 Handle<Map> receiver_map,
                                 Register receiver,
-                                Register scratch_in,
+                                Register scratch,
                                 int argc,
                                 Register* values) {
-  ASSERT(!receiver.is(scratch_in));
-  __ push(receiver);
+  ASSERT(!AreAliased(receiver, scratch));
+  __ Push(receiver);
   // Write the arguments to stack frame.
   for (int i = 0; i < argc; i++) {
+    // TODO(jbramley): Push these in as few Push() calls as possible.
     Register arg = values[argc-1-i];
-    ASSERT(!receiver.is(arg));
-    ASSERT(!scratch_in.is(arg));
-    __ push(arg);
+    ASSERT(!AreAliased(receiver, scratch, arg));
+    __ Push(arg);
   }
+
   ASSERT(optimization.is_simple_api_call());
 
   // Abi for CallApiFunctionStub.
-  Register callee = r0;
-  Register call_data = r4;
-  Register holder = r2;
-  Register api_function_address = r1;
+  Register callee = x0;
+  Register call_data = x4;
+  Register holder = x2;
+  Register api_function_address = x1;
 
   // Put holder in place.
   CallOptimization::HolderLookup holder_lookup;
-  Handle<JSObject> api_holder = optimization.LookupHolderOfExpectedType(
-      receiver_map,
-      &holder_lookup);
+  Handle<JSObject> api_holder =
+      optimization.LookupHolderOfExpectedType(receiver_map, &holder_lookup);
   switch (holder_lookup) {
     case CallOptimization::kHolderIsReceiver:
-      __ Move(holder, receiver);
+      __ Mov(holder, receiver);
       break;
     case CallOptimization::kHolderFound:
-      __ Move(holder, api_holder);
-     break;
+      __ LoadObject(holder, api_holder);
+      break;
     case CallOptimization::kHolderNotFound:
       UNREACHABLE();
       break;
   }
 
   Isolate* isolate = masm->isolate();
   Handle<JSFunction> function = optimization.constant_function();
   Handle<CallHandlerInfo> api_call_info = optimization.api_call_info();
   Handle<Object> call_data_obj(api_call_info->data(), isolate);
 
   // Put callee in place.
-  __ Move(callee, function);
+  __ LoadObject(callee, function);
 
   bool call_data_undefined = false;
   // Put call_data in place.
   if (isolate->heap()->InNewSpace(*call_data_obj)) {
-    __ Move(call_data, api_call_info);
-    __ ldr(call_data, FieldMemOperand(call_data, CallHandlerInfo::kDataOffset));
+    __ LoadObject(call_data, api_call_info);
+    __ Ldr(call_data, FieldMemOperand(call_data, CallHandlerInfo::kDataOffset));
   } else if (call_data_obj->IsUndefined()) {
     call_data_undefined = true;
     __ LoadRoot(call_data, Heap::kUndefinedValueRootIndex);
   } else {
-    __ Move(call_data, call_data_obj);
+    __ LoadObject(call_data, call_data_obj);
   }
 
   // Put api_function_address in place.
   Address function_address = v8::ToCData<Address>(api_call_info->callback());
   ApiFunction fun(function_address);
-  ExternalReference::Type type = ExternalReference::DIRECT_API_CALL;
   ExternalReference ref = ExternalReference(&fun,
-                                            type,
+                                            ExternalReference::DIRECT_API_CALL,
                                             masm->isolate());
-  __ mov(api_function_address, Operand(ref));
+  __ Mov(api_function_address, Operand(ref));
 
   // Jump to stub.
   CallApiFunctionStub stub(true, call_data_undefined, argc);
   __ TailCallStub(&stub);
 }
 
 
 void StubCompiler::GenerateTailCall(MacroAssembler* masm, Handle<Code> code) {
   __ Jump(code, RelocInfo::CODE_TARGET);
 }
 
 
 #undef __
 #define __ ACCESS_MASM(masm())
 
 
 Register StubCompiler::CheckPrototypes(Handle<HeapType> type,
                                        Register object_reg,
                                        Handle<JSObject> holder,
                                        Register holder_reg,
                                        Register scratch1,
                                        Register scratch2,
                                        Handle<Name> name,
                                        Label* miss,
                                        PrototypeCheckType check) {
   Handle<Map> receiver_map(IC::TypeToMap(*type, isolate()));
   // Make sure that the type feedback oracle harvests the receiver map.
   // TODO(svenpanne) Remove this hack when all ICs are reworked.
-  __ mov(scratch1, Operand(receiver_map));
+  __ Mov(scratch1, Operand(receiver_map));
 
-  // Make sure there's no overlap between holder and object registers.
-  ASSERT(!scratch1.is(object_reg) && !scratch1.is(holder_reg));
-  ASSERT(!scratch2.is(object_reg) && !scratch2.is(holder_reg)
-         && !scratch2.is(scratch1));
+  // object_reg and holder_reg registers can alias.
+  ASSERT(!AreAliased(object_reg, scratch1, scratch2));
+  ASSERT(!AreAliased(holder_reg, scratch1, scratch2));
 
   // Keep track of the current object in register reg.
   Register reg = object_reg;
   int depth = 0;
 
   Handle<JSObject> current = Handle<JSObject>::null();
-  if (type->IsConstant()) current = Handle<JSObject>::cast(type->AsConstant());
+  if (type->IsConstant()) {
+    current = Handle<JSObject>::cast(type->AsConstant());
+  }
   Handle<JSObject> prototype = Handle<JSObject>::null();
   Handle<Map> current_map = receiver_map;
   Handle<Map> holder_map(holder->map());
   // Traverse the prototype chain and check the maps in the prototype chain for
   // fast and global objects or do negative lookup for normal objects.
   while (!current_map.is_identical_to(holder_map)) {
     ++depth;
 
     // Only global objects and objects that do not require access
     // checks are allowed in stubs.
     ASSERT(current_map->IsJSGlobalProxyMap() ||
            !current_map->is_access_check_needed());
 
     prototype = handle(JSObject::cast(current_map->prototype()));
     if (current_map->is_dictionary_map() &&
         !current_map->IsJSGlobalObjectMap() &&
         !current_map->IsJSGlobalProxyMap()) {
       if (!name->IsUniqueName()) {
         ASSERT(name->IsString());
         name = factory()->InternalizeString(Handle<String>::cast(name));
       }
       ASSERT(current.is_null() ||
-             current->property_dictionary()->FindEntry(*name) ==
-             NameDictionary::kNotFound);
+             (current->property_dictionary()->FindEntry(*name) ==
+              NameDictionary::kNotFound));
 
       GenerateDictionaryNegativeLookup(masm(), miss, reg, name,
                                        scratch1, scratch2);
 
-      __ ldr(scratch1, FieldMemOperand(reg, HeapObject::kMapOffset));
+      __ Ldr(scratch1, FieldMemOperand(reg, HeapObject::kMapOffset));
       reg = holder_reg;  // From now on the object will be in holder_reg.
-      __ ldr(reg, FieldMemOperand(scratch1, Map::kPrototypeOffset));
+      __ Ldr(reg, FieldMemOperand(scratch1, Map::kPrototypeOffset));
     } else {
       Register map_reg = scratch1;
+      // TODO(jbramley): Skip this load when we don't need the map.
+      __ Ldr(map_reg, FieldMemOperand(reg, HeapObject::kMapOffset));
+
       if (depth != 1 || check == CHECK_ALL_MAPS) {
-        // CheckMap implicitly loads the map of |reg| into |map_reg|.
-        __ CheckMap(reg, map_reg, current_map, miss, DONT_DO_SMI_CHECK);
-      } else {
-        __ ldr(map_reg, FieldMemOperand(reg, HeapObject::kMapOffset));
+        __ CheckMap(map_reg, current_map, miss, DONT_DO_SMI_CHECK);
       }
 
       // Check access rights to the global object.  This has to happen after
       // the map check so that we know that the object is actually a global
       // object.
       if (current_map->IsJSGlobalProxyMap()) {
         __ CheckAccessGlobalProxy(reg, scratch2, miss);
       } else if (current_map->IsJSGlobalObjectMap()) {
         GenerateCheckPropertyCell(
             masm(), Handle<JSGlobalObject>::cast(current), name,
             scratch2, miss);
       }
 
       reg = holder_reg;  // From now on the object will be in holder_reg.
 
       if (heap()->InNewSpace(*prototype)) {
         // The prototype is in new space; we cannot store a reference to it
         // in the code.  Load it from the map.
-        __ ldr(reg, FieldMemOperand(map_reg, Map::kPrototypeOffset));
+        __ Ldr(reg, FieldMemOperand(map_reg, Map::kPrototypeOffset));
       } else {
         // The prototype is in old space; load it directly.
-        __ mov(reg, Operand(prototype));
+        __ Mov(reg, Operand(prototype));
       }
     }
 
     // Go to the next object in the prototype chain.
     current = prototype;
     current_map = handle(current->map());
   }
 
   // Log the check depth.
   LOG(isolate(), IntEvent("check-maps-depth", depth + 1));
 
+  // Check the holder map.
   if (depth != 0 || check == CHECK_ALL_MAPS) {
     // Check the holder map.
     __ CheckMap(reg, scratch1, current_map, miss, DONT_DO_SMI_CHECK);
   }
 
   // Perform security check for access to the global object.
   ASSERT(current_map->IsJSGlobalProxyMap() ||
          !current_map->is_access_check_needed());
   if (current_map->IsJSGlobalProxyMap()) {
     __ CheckAccessGlobalProxy(reg, scratch1, miss);
   }
 
   // Return the register containing the holder.
   return reg;
 }
 
 
 void LoadStubCompiler::HandlerFrontendFooter(Handle<Name> name, Label* miss) {
   if (!miss->is_unused()) {
     Label success;
-    __ b(&success);
-    __ bind(miss);
+    __ B(&success);
+
+    __ Bind(miss);
     TailCallBuiltin(masm(), MissBuiltin(kind()));
-    __ bind(&success);
+
+    __ Bind(&success);
   }
 }
 
 
 void StoreStubCompiler::HandlerFrontendFooter(Handle<Name> name, Label* miss) {
   if (!miss->is_unused()) {
     Label success;
-    __ b(&success);
+    __ B(&success);
+
     GenerateRestoreName(masm(), miss, name);
     TailCallBuiltin(masm(), MissBuiltin(kind()));
-    __ bind(&success);
+
+    __ Bind(&success);
   }
 }
 
 
-Register LoadStubCompiler::CallbackHandlerFrontend(
-    Handle<HeapType> type,
-    Register object_reg,
-    Handle<JSObject> holder,
-    Handle<Name> name,
-    Handle<Object> callback) {
+Register LoadStubCompiler::CallbackHandlerFrontend(Handle<HeapType> type,
+                                                   Register object_reg,
+                                                   Handle<JSObject> holder,
+                                                   Handle<Name> name,
+                                                   Handle<Object> callback) {
   Label miss;
 
   Register reg = HandlerFrontendHeader(type, object_reg, holder, name, &miss);
 
+  // TODO(jbramely): HandlerFrontendHeader returns its result in scratch1(), so
+  // we can't use it below, but that isn't very obvious. Is there a better way
+  // of handling this?
+
   if (!holder->HasFastProperties() && !holder->IsJSGlobalObject()) {
-    ASSERT(!reg.is(scratch2()));
-    ASSERT(!reg.is(scratch3()));
-    ASSERT(!reg.is(scratch4()));
+    ASSERT(!AreAliased(reg, scratch2(), scratch3(), scratch4()));
 
     // Load the properties dictionary.
     Register dictionary = scratch4();
-    __ ldr(dictionary, FieldMemOperand(reg, JSObject::kPropertiesOffset));
+    __ Ldr(dictionary, FieldMemOperand(reg, JSObject::kPropertiesOffset));
 
     // Probe the dictionary.
     Label probe_done;
     NameDictionaryLookupStub::GeneratePositiveLookup(masm(),
                                                      &miss,
                                                      &probe_done,
                                                      dictionary,
                                                      this->name(),
                                                      scratch2(),
                                                      scratch3());
-    __ bind(&probe_done);
+    __ Bind(&probe_done);
 
     // If probing finds an entry in the dictionary, scratch3 contains the
     // pointer into the dictionary. Check that the value is the callback.
     Register pointer = scratch3();
     const int kElementsStartOffset = NameDictionary::kHeaderSize +
         NameDictionary::kElementsStartIndex * kPointerSize;
     const int kValueOffset = kElementsStartOffset + kPointerSize;
-    __ ldr(scratch2(), FieldMemOperand(pointer, kValueOffset));
-    __ cmp(scratch2(), Operand(callback));
-    __ b(ne, &miss);
+    __ Ldr(scratch2(), FieldMemOperand(pointer, kValueOffset));
+    __ Cmp(scratch2(), Operand(callback));
+    __ B(ne, &miss);
   }
 
   HandlerFrontendFooter(name, &miss);
   return reg;
 }
 
 
 void LoadStubCompiler::GenerateLoadField(Register reg,
                                          Handle<JSObject> holder,
                                          PropertyIndex field,
                                          Representation representation) {
-  if (!reg.is(receiver())) __ mov(receiver(), reg);
+  __ Mov(receiver(), reg);
   if (kind() == Code::LOAD_IC) {
     LoadFieldStub stub(field.is_inobject(holder),
                        field.translate(holder),
                        representation);
     GenerateTailCall(masm(), stub.GetCode(isolate()));
   } else {
     KeyedLoadFieldStub stub(field.is_inobject(holder),
                             field.translate(holder),
                             representation);
     GenerateTailCall(masm(), stub.GetCode(isolate()));
   }
 }
 
 
 void LoadStubCompiler::GenerateLoadConstant(Handle<Object> value) {
   // Return the constant value.
-  __ Move(r0, value);
+  __ LoadObject(x0, value);
   __ Ret();
 }
 
 
 void LoadStubCompiler::GenerateLoadCallback(
     const CallOptimization& call_optimization,
     Handle<Map> receiver_map) {
   GenerateFastApiCall(
-      masm(), call_optimization, receiver_map,
-      receiver(), scratch3(), 0, NULL);
+      masm(), call_optimization, receiver_map, receiver(), scratch3(), 0, NULL);
 }
 
 
 void LoadStubCompiler::GenerateLoadCallback(
     Register reg,
     Handle<ExecutableAccessorInfo> callback) {
-  // Build AccessorInfo::args_ list on the stack and push property name below
-  // the exit frame to make GC aware of them and store pointers to them.
+  ASSERT(!AreAliased(scratch2(), scratch3(), scratch4(), reg));
+
+  // Build ExecutableAccessorInfo::args_ list on the stack and push property
+  // name below the exit frame to make GC aware of them and store pointers to
+  // them.
   STATIC_ASSERT(PropertyCallbackArguments::kHolderIndex == 0);
   STATIC_ASSERT(PropertyCallbackArguments::kIsolateIndex == 1);
   STATIC_ASSERT(PropertyCallbackArguments::kReturnValueDefaultValueIndex == 2);
   STATIC_ASSERT(PropertyCallbackArguments::kReturnValueOffset == 3);
   STATIC_ASSERT(PropertyCallbackArguments::kDataIndex == 4);
   STATIC_ASSERT(PropertyCallbackArguments::kThisIndex == 5);
   STATIC_ASSERT(PropertyCallbackArguments::kArgsLength == 6);
-  ASSERT(!scratch2().is(reg));
-  ASSERT(!scratch3().is(reg));
-  ASSERT(!scratch4().is(reg));
-  __ push(receiver());
+
+  __ Push(receiver());
+
   if (heap()->InNewSpace(callback->data())) {
-    __ Move(scratch3(), callback);
-    __ ldr(scratch3(), FieldMemOperand(scratch3(),
+    __ Mov(scratch3(), Operand(callback));
+    __ Ldr(scratch3(), FieldMemOperand(scratch3(),
                                        ExecutableAccessorInfo::kDataOffset));
   } else {
-    __ Move(scratch3(), Handle<Object>(callback->data(), isolate()));
+    __ Mov(scratch3(), Operand(Handle<Object>(callback->data(), isolate())));
   }
-  __ push(scratch3());
-  __ LoadRoot(scratch3(), Heap::kUndefinedValueRootIndex);
-  __ mov(scratch4(), scratch3());
+  // TODO(jbramley): Find another scratch register and combine the pushes
+  // together. Can we use scratch1() here?
+  __ LoadRoot(scratch4(), Heap::kUndefinedValueRootIndex);
   __ Push(scratch3(), scratch4());
-  __ mov(scratch4(),
-         Operand(ExternalReference::isolate_address(isolate())));
-  __ Push(scratch4(), reg);
-  __ mov(scratch2(), sp);  // scratch2 = PropertyAccessorInfo::args_
-  __ push(name());
+  __ Mov(scratch3(), Operand(ExternalReference::isolate_address(isolate())));
+  __ Push(scratch4(), scratch3(), reg, name());
 
-  // Abi for CallApiGetter
-  Register getter_address_reg = r2;
+  Register args_addr = scratch2();
+  __ Add(args_addr, __ StackPointer(), kPointerSize);
 
+  // Stack at this point:
+  //              sp[40] callback data
+  //              sp[32] undefined
+  //              sp[24] undefined
+  //              sp[16] isolate
+  // args_addr -> sp[8]  reg
+  //              sp[0]  name
+
+  // Abi for CallApiGetter.
+  Register getter_address_reg = x2;
+
+  // Set up the call.
   Address getter_address = v8::ToCData<Address>(callback->getter());
   ApiFunction fun(getter_address);
   ExternalReference::Type type = ExternalReference::DIRECT_GETTER_CALL;
   ExternalReference ref = ExternalReference(&fun, type, isolate());
-  __ mov(getter_address_reg, Operand(ref));
+  __ Mov(getter_address_reg, Operand(ref));
 
   CallApiGetterStub stub;
   __ TailCallStub(&stub);
 }
 
 
 void LoadStubCompiler::GenerateLoadInterceptor(
     Register holder_reg,
     Handle<Object> object,
     Handle<JSObject> interceptor_holder,
     LookupResult* lookup,
     Handle<Name> name) {
+  ASSERT(!AreAliased(receiver(), this->name(),
+                     scratch1(), scratch2(), scratch3()));
   ASSERT(interceptor_holder->HasNamedInterceptor());
   ASSERT(!interceptor_holder->GetNamedInterceptor()->getter()->IsUndefined());
 
   // So far the most popular follow ups for interceptor loads are FIELD
-  // and CALLBACKS, so inline only them, other cases may be added
-  // later.
+  // and CALLBACKS, so inline only them, other cases may be added later.
   bool compile_followup_inline = false;
   if (lookup->IsFound() && lookup->IsCacheable()) {
     if (lookup->IsField()) {
       compile_followup_inline = true;
     } else if (lookup->type() == CALLBACKS &&
                lookup->GetCallbackObject()->IsExecutableAccessorInfo()) {
       ExecutableAccessorInfo* callback =
           ExecutableAccessorInfo::cast(lookup->GetCallbackObject());
       compile_followup_inline = callback->getter() != NULL &&
           callback->IsCompatibleReceiver(*object);
     }
   }
 
   if (compile_followup_inline) {
     // Compile the interceptor call, followed by inline code to load the
     // property from further up the prototype chain if the call fails.
     // Check that the maps haven't changed.
     ASSERT(holder_reg.is(receiver()) || holder_reg.is(scratch1()));
 
     // Preserve the receiver register explicitly whenever it is different from
     // the holder and it is needed should the interceptor return without any
     // result. The CALLBACKS case needs the receiver to be passed into C++ code,
     // the FIELD case might cause a miss during the prototype check.
     bool must_perfrom_prototype_check = *interceptor_holder != lookup->holder();
-    bool must_preserve_receiver_reg = !receiver().is(holder_reg) &&
+    bool must_preserve_receiver_reg = !receiver().Is(holder_reg) &&
         (lookup->type() == CALLBACKS || must_perfrom_prototype_check);
 
     // Save necessary data before invoking an interceptor.
     // Requires a frame to make GC aware of pushed pointers.
     {
       FrameScope frame_scope(masm(), StackFrame::INTERNAL);
       if (must_preserve_receiver_reg) {
         __ Push(receiver(), holder_reg, this->name());
       } else {
         __ Push(holder_reg, this->name());
       }
       // Invoke an interceptor.  Note: map checks from receiver to
       // interceptor's holder has been compiled before (see a caller
       // of this method.)
       CompileCallLoadPropertyWithInterceptor(
           masm(), receiver(), holder_reg, this->name(), interceptor_holder,
           IC::kLoadPropertyWithInterceptorOnly);
 
       // Check if interceptor provided a value for property.  If it's
       // the case, return immediately.
       Label interceptor_failed;
-      __ LoadRoot(scratch1(), Heap::kNoInterceptorResultSentinelRootIndex);
-      __ cmp(r0, scratch1());
-      __ b(eq, &interceptor_failed);
+      __ JumpIfRoot(x0,
+                    Heap::kNoInterceptorResultSentinelRootIndex,
+                    &interceptor_failed);
       frame_scope.GenerateLeaveFrame();
       __ Ret();
 
-      __ bind(&interceptor_failed);
-      __ pop(this->name());
-      __ pop(holder_reg);
+      __ Bind(&interceptor_failed);
       if (must_preserve_receiver_reg) {
-        __ pop(receiver());
+        __ Pop(this->name(), holder_reg, receiver());
+      } else {
+        __ Pop(this->name(), holder_reg);
       }
       // Leave the internal frame.
     }
-
     GenerateLoadPostInterceptor(holder_reg, interceptor_holder, name, lookup);
   } else {  // !compile_followup_inline
     // Call the runtime system to load the interceptor.
     // Check that the maps haven't changed.
-    PushInterceptorArguments(masm(), receiver(), holder_reg,
-                             this->name(), interceptor_holder);
+    PushInterceptorArguments(
+        masm(), receiver(), holder_reg, this->name(), interceptor_holder);
 
     ExternalReference ref =
         ExternalReference(IC_Utility(IC::kLoadPropertyWithInterceptorForLoad),
                           isolate());
     __ TailCallExternalReference(ref, StubCache::kInterceptorArgsLength, 1);
   }
 }
 
 
 void StubCompiler::GenerateBooleanCheck(Register object, Label* miss) {
   Label success;
   // Check that the object is a boolean.
-  __ LoadRoot(ip, Heap::kTrueValueRootIndex);
-  __ cmp(object, ip);
-  __ b(eq, &success);
-  __ LoadRoot(ip, Heap::kFalseValueRootIndex);
-  __ cmp(object, ip);
-  __ b(ne, miss);
-  __ bind(&success);
+  // TODO(all): Optimize this like LCodeGen::DoDeferredTaggedToI.
+  __ JumpIfRoot(object, Heap::kTrueValueRootIndex, &success);
+  __ JumpIfNotRoot(object, Heap::kFalseValueRootIndex, miss);
+  __ Bind(&success);
 }
 
 
 Handle<Code> StoreStubCompiler::CompileStoreCallback(
     Handle<JSObject> object,
     Handle<JSObject> holder,
     Handle<Name> name,
     Handle<ExecutableAccessorInfo> callback) {
+  ASM_LOCATION("StoreStubCompiler::CompileStoreCallback");
   Register holder_reg = HandlerFrontend(
       IC::CurrentTypeOf(object, isolate()), receiver(), holder, name);
 
   // Stub never generated for non-global objects that require access checks.
   ASSERT(holder->IsJSGlobalProxy() || !holder->IsAccessCheckNeeded());
 
-  __ push(receiver());  // receiver
-  __ push(holder_reg);
-  __ mov(ip, Operand(callback));  // callback info
-  __ push(ip);
-  __ mov(ip, Operand(name));
-  __ Push(ip, value());
+  // TODO(jbramley): Make Push take more than four arguments and combine these
+  // two calls.
+  __ Push(receiver(), holder_reg);
+  __ Mov(scratch1(), Operand(callback));
+  __ Mov(scratch2(), Operand(name));
+  __ Push(scratch1(), scratch2(), value());
 
   // Do tail-call to the runtime system.
   ExternalReference store_callback_property =
       ExternalReference(IC_Utility(IC::kStoreCallbackProperty), isolate());
   __ TailCallExternalReference(store_callback_property, 5, 1);
 
   // Return the generated code.
   return GetCode(kind(), Code::FAST, name);
 }
 
 
-Handle<Code> StoreStubCompiler::CompileStoreCallback(
-    Handle<JSObject> object,
-    Handle<JSObject> holder,
-    Handle<Name> name,
-    const CallOptimization& call_optimization) {
-  HandlerFrontend(IC::CurrentTypeOf(object, isolate()),
-                  receiver(), holder, name);
-
-  Register values[] = { value() };
-  GenerateFastApiCall(
-      masm(), call_optimization, handle(object->map()),
-      receiver(), scratch3(), 1, values);
-
-  // Return the generated code.
-  return GetCode(kind(), Code::FAST, name);
-}
-
-
 #undef __
 #define __ ACCESS_MASM(masm)
 
 
 void StoreStubCompiler::GenerateStoreViaSetter(
     MacroAssembler* masm,
     Handle<HeapType> type,
     Handle<JSFunction> setter) {
   // ----------- S t a t e -------------
-  //  -- r0    : value
-  //  -- r1    : receiver
-  //  -- r2    : name
+  //  -- x0    : value
+  //  -- x1    : receiver
+  //  -- x2    : name
   //  -- lr    : return address
   // -----------------------------------
+  Register value = x0;
+  Register receiver = x1;
+  Label miss;
+
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
-    Register receiver = r1;
-    Register value = r0;
 
     // Save value register, so we can restore it later.
-    __ push(value);
+    __ Push(value);
 
     if (!setter.is_null()) {
       // Call the JavaScript setter with receiver and value on the stack.
       if (IC::TypeToMap(*type, masm->isolate())->IsJSGlobalObjectMap()) {
         // Swap in the global receiver.
-        __ ldr(receiver,
+        __ Ldr(receiver,
                FieldMemOperand(
                    receiver, JSGlobalObject::kGlobalReceiverOffset));
       }
       __ Push(receiver, value);
       ParameterCount actual(1);
       ParameterCount expected(setter);
       __ InvokeFunction(setter, expected, actual,
                         CALL_FUNCTION, NullCallWrapper());
     } else {
       // If we generate a global code snippet for deoptimization only, remember
       // the place to continue after deoptimization.
       masm->isolate()->heap()->SetSetterStubDeoptPCOffset(masm->pc_offset());
     }
 
     // We have to return the passed value, not the return value of the setter.
-    __ pop(r0);
+    __ Pop(value);
 
     // Restore context register.
-    __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+    __ Ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   }
   __ Ret();
 }
 
 
 #undef __
 #define __ ACCESS_MASM(masm())
 
 
 Handle<Code> StoreStubCompiler::CompileStoreInterceptor(
     Handle<JSObject> object,
     Handle<Name> name) {
   Label miss;
 
+  ASM_LOCATION("StoreStubCompiler::CompileStoreInterceptor");
+
   // Check that the map of the object hasn't changed.
   __ CheckMap(receiver(), scratch1(), Handle<Map>(object->map()), &miss,
               DO_SMI_CHECK);
 
   // Perform global security token check if needed.
   if (object->IsJSGlobalProxy()) {
     __ CheckAccessGlobalProxy(receiver(), scratch1(), &miss);
   }
 
-  // Stub is never generated for non-global objects that require access
-  // checks.
+  // Stub is never generated for non-global objects that require access checks.
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   __ Push(receiver(), this->name(), value());
 
   // Do tail-call to the runtime system.
   ExternalReference store_ic_property =
       ExternalReference(IC_Utility(IC::kStoreInterceptorProperty), isolate());
   __ TailCallExternalReference(store_ic_property, 3, 1);
 
   // Handle store cache miss.
-  __ bind(&miss);
+  __ Bind(&miss);
   TailCallBuiltin(masm(), MissBuiltin(kind()));
 
   // Return the generated code.
   return GetCode(kind(), Code::FAST, name);
 }
 
 
 Handle<Code> LoadStubCompiler::CompileLoadNonexistent(Handle<HeapType> type,
                                                       Handle<JSObject> last,
                                                       Handle<Name> name) {
   NonexistentHandlerFrontend(type, last, name);
 
   // Return undefined if maps of the full prototype chain are still the
   // same and no global property with this name contains a value.
-  __ LoadRoot(r0, Heap::kUndefinedValueRootIndex);
+  __ LoadRoot(x0, Heap::kUndefinedValueRootIndex);
   __ Ret();
 
   // Return the generated code.
   return GetCode(kind(), Code::FAST, name);
 }
 
 
+// TODO(all): The so-called scratch registers are significant in some cases. For
+// example, KeyedStoreStubCompiler::registers()[3] (x3) is actually used for
+// KeyedStoreCompiler::transition_map(). We should verify which registers are
+// actually scratch registers, and which are important. For now, we use the same
+// assignments as ARM to remain on the safe side.
+
 Register* LoadStubCompiler::registers() {
   // receiver, name, scratch1, scratch2, scratch3, scratch4.
-  static Register registers[] = { r0, r2, r3, r1, r4, r5 };
+  static Register registers[] = { x0, x2, x3, x1, x4, x5 };
   return registers;
 }
 
 
 Register* KeyedLoadStubCompiler::registers() {
-  // receiver, name, scratch1, scratch2, scratch3, scratch4.
-  static Register registers[] = { r1, r0, r2, r3, r4, r5 };
+  // receiver, name/key, scratch1, scratch2, scratch3, scratch4.
+  static Register registers[] = { x1, x0, x2, x3, x4, x5 };
   return registers;
 }
 
 
 Register* StoreStubCompiler::registers() {
   // receiver, name, value, scratch1, scratch2, scratch3.
-  static Register registers[] = { r1, r2, r0, r3, r4, r5 };
+  static Register registers[] = { x1, x2, x0, x3, x4, x5 };
   return registers;
 }
 
 
 Register* KeyedStoreStubCompiler::registers() {
   // receiver, name, value, scratch1, scratch2, scratch3.
-  static Register registers[] = { r2, r1, r0, r3, r4, r5 };
+  static Register registers[] = { x2, x1, x0, x3, x4, x5 };
   return registers;
 }
 
 
 #undef __
 #define __ ACCESS_MASM(masm)
 
-
 void LoadStubCompiler::GenerateLoadViaGetter(MacroAssembler* masm,
                                              Handle<HeapType> type,
                                              Register receiver,
                                              Handle<JSFunction> getter) {
-  // ----------- S t a t e -------------
-  //  -- r0    : receiver
-  //  -- r2    : name
-  //  -- lr    : return address
-  // -----------------------------------
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
 
     if (!getter.is_null()) {
       // Call the JavaScript getter with the receiver on the stack.
       if (IC::TypeToMap(*type, masm->isolate())->IsJSGlobalObjectMap()) {
         // Swap in the global receiver.
-        __ ldr(receiver,
+        __ Ldr(receiver,
                 FieldMemOperand(
                     receiver, JSGlobalObject::kGlobalReceiverOffset));
       }
-      __ push(receiver);
+      __ Push(receiver);
       ParameterCount actual(0);
       ParameterCount expected(getter);
       __ InvokeFunction(getter, expected, actual,
                         CALL_FUNCTION, NullCallWrapper());
     } else {
       // If we generate a global code snippet for deoptimization only, remember
       // the place to continue after deoptimization.
       masm->isolate()->heap()->SetGetterStubDeoptPCOffset(masm->pc_offset());
     }
 
     // Restore context register.
-    __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+    __ Ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   }
   __ Ret();
 }
 
 
 #undef __
 #define __ ACCESS_MASM(masm())
 
 
 Handle<Code> LoadStubCompiler::CompileLoadGlobal(
     Handle<HeapType> type,
     Handle<GlobalObject> global,
     Handle<PropertyCell> cell,
     Handle<Name> name,
     bool is_dont_delete) {
   Label miss;
   HandlerFrontendHeader(type, receiver(), global, name, &miss);
 
   // Get the value from the cell.
-  __ mov(r3, Operand(cell));
-  __ ldr(r4, FieldMemOperand(r3, Cell::kValueOffset));
+  __ Mov(x3, Operand(cell));
+  __ Ldr(x4, FieldMemOperand(x3, Cell::kValueOffset));
 
   // Check for deleted property if property can actually be deleted.
   if (!is_dont_delete) {
-    __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
-    __ cmp(r4, ip);
-    __ b(eq, &miss);
+    __ JumpIfRoot(x4, Heap::kTheHoleValueRootIndex, &miss);
   }
 
   Counters* counters = isolate()->counters();
-  __ IncrementCounter(counters->named_load_global_stub(), 1, r1, r3);
-  __ mov(r0, r4);
+  __ IncrementCounter(counters->named_load_global_stub(), 1, x1, x3);
+  __ Mov(x0, x4);
   __ Ret();
 
   HandlerFrontendFooter(name, &miss);
 
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 Handle<Code> BaseLoadStoreStubCompiler::CompilePolymorphicIC(
     TypeHandleList* types,
     CodeHandleList* handlers,
     Handle<Name> name,
     Code::StubType type,
     IcCheckType check) {
   Label miss;
 
   if (check == PROPERTY &&
       (kind() == Code::KEYED_LOAD_IC || kind() == Code::KEYED_STORE_IC)) {
-    __ cmp(this->name(), Operand(name));
-    __ b(ne, &miss);
+    __ CompareAndBranch(this->name(), Operand(name), ne, &miss);
   }
 
   Label number_case;
   Label* smi_target = IncludesNumberType(types) ? &number_case : &miss;
   __ JumpIfSmi(receiver(), smi_target);
 
   Register map_reg = scratch1();
-
+  __ Ldr(map_reg, FieldMemOperand(receiver(), HeapObject::kMapOffset));
   int receiver_count = types->length();
   int number_of_handled_maps = 0;
-  __ ldr(map_reg, FieldMemOperand(receiver(), HeapObject::kMapOffset));
   for (int current = 0; current < receiver_count; ++current) {
     Handle<HeapType> type = types->at(current);
     Handle<Map> map = IC::TypeToMap(*type, isolate());
     if (!map->is_deprecated()) {
       number_of_handled_maps++;
-      __ mov(ip, Operand(map));
-      __ cmp(map_reg, ip);
+      Label try_next;
+      __ Cmp(map_reg, Operand(map));
+      __ B(ne, &try_next);
       if (type->Is(HeapType::Number())) {
         ASSERT(!number_case.is_unused());
-        __ bind(&number_case);
+        __ Bind(&number_case);
       }
-      __ Jump(handlers->at(current), RelocInfo::CODE_TARGET, eq);
+      __ Jump(handlers->at(current), RelocInfo::CODE_TARGET);
+      __ Bind(&try_next);
     }
   }
   ASSERT(number_of_handled_maps != 0);
 
-  __ bind(&miss);
+  __ Bind(&miss);
   TailCallBuiltin(masm(), MissBuiltin(kind()));
 
   // Return the generated code.
   InlineCacheState state =
-      number_of_handled_maps > 1 ? POLYMORPHIC : MONOMORPHIC;
+      (number_of_handled_maps > 1) ? POLYMORPHIC : MONOMORPHIC;
   return GetICCode(kind(), type, name, state);
 }
 
 
 Handle<Code> KeyedStoreStubCompiler::CompileStorePolymorphic(
     MapHandleList* receiver_maps,
     CodeHandleList* handler_stubs,
     MapHandleList* transitioned_maps) {
   Label miss;
+
+  ASM_LOCATION("KeyedStoreStubCompiler::CompileStorePolymorphic");
+
   __ JumpIfSmi(receiver(), &miss);
 
   int receiver_count = receiver_maps->length();
-  __ ldr(scratch1(), FieldMemOperand(receiver(), HeapObject::kMapOffset));
-  for (int i = 0; i < receiver_count; ++i) {
-    __ mov(ip, Operand(receiver_maps->at(i)));
-    __ cmp(scratch1(), ip);
-    if (transitioned_maps->at(i).is_null()) {
-      __ Jump(handler_stubs->at(i), RelocInfo::CODE_TARGET, eq);
-    } else {
-      Label next_map;
-      __ b(ne, &next_map);
-      __ mov(transition_map(), Operand(transitioned_maps->at(i)));
-      __ Jump(handler_stubs->at(i), RelocInfo::CODE_TARGET, al);
-      __ bind(&next_map);
+  __ Ldr(scratch1(), FieldMemOperand(receiver(), HeapObject::kMapOffset));
+  for (int i = 0; i < receiver_count; i++) {
+    __ Cmp(scratch1(), Operand(receiver_maps->at(i)));
+
+    Label skip;
+    __ B(&skip, ne);
+    if (!transitioned_maps->at(i).is_null()) {
+      // This argument is used by the handler stub. For example, see
+      // ElementsTransitionGenerator::GenerateMapChangeElementsTransition.
+      __ Mov(transition_map(), Operand(transitioned_maps->at(i)));
     }
+    __ Jump(handler_stubs->at(i), RelocInfo::CODE_TARGET);
+    __ Bind(&skip);
   }
 
-  __ bind(&miss);
+  __ Bind(&miss);
   TailCallBuiltin(masm(), MissBuiltin(kind()));
 
-  // Return the generated code.
   return GetICCode(
       kind(), Code::NORMAL, factory()->empty_string(), POLYMORPHIC);
 }
 
 
+Handle<Code> StoreStubCompiler::CompileStoreCallback(
+    Handle<JSObject> object,
+    Handle<JSObject> holder,
+    Handle<Name> name,
+    const CallOptimization& call_optimization) {
+  HandlerFrontend(IC::CurrentTypeOf(object, isolate()),
+                  receiver(), holder, name);
+
+  Register values[] = { value() };
+  GenerateFastApiCall(masm(), call_optimization, handle(object->map()),
+                      receiver(), scratch3(), 1, values);
+
+  // Return the generated code.
+  return GetCode(kind(), Code::FAST, name);
+}
+
+
 #undef __
 #define __ ACCESS_MASM(masm)
 
-
 void KeyedLoadStubCompiler::GenerateLoadDictionaryElement(
     MacroAssembler* masm) {
   // ---------- S t a t e --------------
   //  -- lr     : return address
-  //  -- r0     : key
-  //  -- r1     : receiver
+  //  -- x0     : key
+  //  -- x1     : receiver
   // -----------------------------------
   Label slow, miss;
 
-  Register key = r0;
-  Register receiver = r1;
+  Register result = x0;
+  Register key = x0;
+  Register receiver = x1;
 
-  __ UntagAndJumpIfNotSmi(r2, key, &miss);
-  __ ldr(r4, FieldMemOperand(receiver, JSObject::kElementsOffset));
-  __ LoadFromNumberDictionary(&slow, r4, key, r0, r2, r3, r5);
+  __ JumpIfNotSmi(key, &miss);
+  __ Ldr(x4, FieldMemOperand(receiver, JSObject::kElementsOffset));
+  __ LoadFromNumberDictionary(&slow, x4, key, result, x2, x3, x5, x6);
   __ Ret();
 
-  __ bind(&slow);
+  __ Bind(&slow);
   __ IncrementCounter(
-      masm->isolate()->counters()->keyed_load_external_array_slow(),
-      1, r2, r3);
-
-  // ---------- S t a t e --------------
-  //  -- lr     : return address
-  //  -- r0     : key
-  //  -- r1     : receiver
-  // -----------------------------------
+      masm->isolate()->counters()->keyed_load_external_array_slow(), 1, x2, x3);
   TailCallBuiltin(masm, Builtins::kKeyedLoadIC_Slow);
 
   // Miss case, call the runtime.
-  __ bind(&miss);
-
-  // ---------- S t a t e --------------
-  //  -- lr     : return address
-  //  -- r0     : key
-  //  -- r1     : receiver
-  // -----------------------------------
+  __ Bind(&miss);
   TailCallBuiltin(masm, Builtins::kKeyedLoadIC_Miss);
 }
 
 
-#undef __
-
 } }  // namespace v8::internal
 
-#endif  // V8_TARGET_ARCH_ARM
+#endif  // V8_TARGET_ARCH_A64