[builtins] Migrate String.prototype.charCodeAt and String.prototype.charAt to TurboFan.

src/compiler/code-stub-assembler.cc

Index: src/compiler/code-stub-assembler.cc
diff --git a/src/compiler/code-stub-assembler.cc b/src/compiler/code-stub-assembler.cc
index f50fa1a14ba028d63fd90f25ee302bbbe380a8eb..772a1bf0c67a2ca19442428abca3743a88566ae1 100644
--- a/src/compiler/code-stub-assembler.cc
+++ b/src/compiler/code-stub-assembler.cc
@@ -114,10 +114,22 @@ Node* CodeStubAssembler::BooleanMapConstant() {
   return HeapConstant(isolate()->factory()->boolean_map());
 }
 
+Node* CodeStubAssembler::EmptyStringConstant() {
+  return LoadRoot(Heap::kempty_stringRootIndex);
+}
+
 Node* CodeStubAssembler::HeapNumberMapConstant() {
   return HeapConstant(isolate()->factory()->heap_number_map());
 }
 
+Node* CodeStubAssembler::NaNConstant() {
+  return LoadRoot(Heap::kNanValueRootIndex);
+}
+
+Node* CodeStubAssembler::NoContextConstant() {
+  return SmiConstant(Smi::FromInt(0));
+}
+
 Node* CodeStubAssembler::NullConstant() {
   return LoadRoot(Heap::kNullValueRootIndex);
 }
@@ -349,6 +361,13 @@ Node* CodeStubAssembler::SmiUntag(Node* value) {
   return raw_assembler_->WordSar(value, SmiShiftBitsConstant());
 }
 
+Node* CodeStubAssembler::SmiFromWord32(Node* value) {
+  if (raw_assembler_->machine()->Is64()) {
+    value = raw_assembler_->ChangeInt32ToInt64(value);
+  }
+  return raw_assembler_->WordShl(value, SmiShiftBitsConstant());
+}
+
 Node* CodeStubAssembler::SmiToWord32(Node* value) {
   Node* result = raw_assembler_->WordSar(value, SmiShiftBitsConstant());
   if (raw_assembler_->machine()->Is64()) {
@@ -375,6 +394,10 @@ Node* CodeStubAssembler::SmiSubWithOverflow(Node* a, Node* b) {
 
 Node* CodeStubAssembler::SmiEqual(Node* a, Node* b) { return WordEqual(a, b); }
 
+Node* CodeStubAssembler::SmiAboveOrEqual(Node* a, Node* b) {
+  return UintPtrGreaterThanOrEqual(a, b);
+}
+
 Node* CodeStubAssembler::SmiLessThan(Node* a, Node* b) {
   return IntPtrLessThan(a, b);
 }
@@ -436,6 +459,12 @@ Node* CodeStubAssembler::LoadObjectField(Node* object, int offset,
                               IntPtrConstant(offset - kHeapObjectTag));
 }
 
+Node* CodeStubAssembler::StoreObjectFieldNoWriteBarrier(
+    Node* object, int offset, Node* value, MachineRepresentation rep) {
+  return StoreNoWriteBarrier(rep, object,
+                             IntPtrConstant(offset - kHeapObjectTag), value);
+}
+
 Node* CodeStubAssembler::LoadHeapNumberValue(Node* object) {
   return Load(MachineType::Float64(), object,
               IntPtrConstant(HeapNumber::kValueOffset - kHeapObjectTag));
@@ -483,10 +512,13 @@ Node* CodeStubAssembler::LoadNameHash(Node* name) {
 }
 
 Node* CodeStubAssembler::LoadFixedArrayElementInt32Index(
-    Node* object, Node* int32_index, int additional_offset) {
+    Node* object, Node* index, int additional_offset) {
   Node* header_size = IntPtrConstant(additional_offset +
                                      FixedArray::kHeaderSize - kHeapObjectTag);
-  Node* scaled_index = WordShl(int32_index, IntPtrConstant(kPointerSizeLog2));
+  if (raw_assembler_->machine()->Is64()) {
+    index = ChangeInt32ToInt64(index);
+  }
+  Node* scaled_index = WordShl(index, IntPtrConstant(kPointerSizeLog2));
   Node* offset = IntPtrAdd(scaled_index, header_size);
   return Load(MachineType::AnyTagged(), object, offset);
 }
@@ -523,6 +555,18 @@ Node* CodeStubAssembler::StoreFixedArrayElementNoWriteBarrier(Node* object,
                              value);
 }
 
+Node* CodeStubAssembler::StoreFixedArrayElementInt32Index(Node* object,
+                                                          Node* index,
+                                                          Node* value) {
+  if (raw_assembler_->machine()->Is64()) {
+    index = ChangeInt32ToInt64(index);
+  }
+  Node* offset =
+      IntPtrAdd(WordShl(index, IntPtrConstant(kPointerSizeLog2)),
+                IntPtrConstant(FixedArray::kHeaderSize - kHeapObjectTag));
+  return Store(MachineRepresentation::kTagged, object, offset, value);
+}
+
 Node* CodeStubAssembler::LoadRoot(Heap::RootListIndex root_index) {
   if (isolate()->heap()->RootCanBeTreatedAsConstant(root_index)) {
     Handle<Object> root = isolate()->heap()->root_handle(root_index);
@@ -672,6 +716,26 @@ Node* CodeStubAssembler::AllocateHeapNumberWithValue(Node* value) {
   return result;
 }
 
+Node* CodeStubAssembler::AllocateSeqOneByteString(int length) {
+  Node* result = Allocate(SeqOneByteString::SizeFor(length));
+  StoreMapNoWriteBarrier(result, LoadRoot(Heap::kOneByteStringMapRootIndex));
+  StoreObjectFieldNoWriteBarrier(result, SeqOneByteString::kLengthOffset,
+                                 SmiConstant(Smi::FromInt(length)));
+  StoreObjectFieldNoWriteBarrier(result, SeqOneByteString::kHashFieldOffset,
+                                 IntPtrConstant(String::kEmptyHashField));
+  return result;
+}
+
+Node* CodeStubAssembler::AllocateSeqTwoByteString(int length) {
+  Node* result = Allocate(SeqTwoByteString::SizeFor(length));
+  StoreMapNoWriteBarrier(result, LoadRoot(Heap::kStringMapRootIndex));
+  StoreObjectFieldNoWriteBarrier(result, SeqTwoByteString::kLengthOffset,
+                                 SmiConstant(Smi::FromInt(length)));
+  StoreObjectFieldNoWriteBarrier(result, SeqTwoByteString::kHashFieldOffset,
+                                 IntPtrConstant(String::kEmptyHashField));
+  return result;
+}
+
 Node* CodeStubAssembler::Load(MachineType rep, Node* base) {
   return raw_assembler_->Load(rep, base);
 }
@@ -921,6 +985,297 @@ Node* CodeStubAssembler::TruncateTaggedToWord32(Node* context, Node* value) {
   return var_result.value();
 }
 
+Node* CodeStubAssembler::ToThisString(Node* context, Node* value,
+                                      char const* method_name) {
+  Variable var_value(this, MachineRepresentation::kTagged);
+  var_value.Bind(value);
+
+  // Check if the {value} is a Smi or a HeapObject.
+  Label if_valueissmi(this, Label::kDeferred), if_valueisnotsmi(this),
+      if_valueisstring(this);
+  Branch(WordIsSmi(value), &if_valueissmi, &if_valueisnotsmi);
+  Bind(&if_valueisnotsmi);
+  {
+    // Load the instance type of the {value}.
+    Node* value_instance_type = LoadInstanceType(value);
+
+    // Check if the {value} is already String.
+    Label if_valueisnotstring(this, Label::kDeferred);
+    Branch(
+        Int32LessThan(value_instance_type, Int32Constant(FIRST_NONSTRING_TYPE)),
+        &if_valueisstring, &if_valueisnotstring);
+    Bind(&if_valueisnotstring);
+    {
+      // Check if the {value} is null.
+      Label if_valueisnullorundefined(this, Label::kDeferred),
+          if_valueisnotnullorundefined(this, Label::kDeferred),
+          if_valueisnotnull(this, Label::kDeferred);
+      Branch(WordEqual(value, NullConstant()), &if_valueisnullorundefined,
+             &if_valueisnotnull);
+      Bind(&if_valueisnotnull);
+      {
+        // Check if the {value} is undefined.
+        Branch(WordEqual(value, UndefinedConstant()),
+               &if_valueisnullorundefined, &if_valueisnotnullorundefined);
+        Bind(&if_valueisnotnullorundefined);
+        {
+          // Convert the {value} to a String.
+          Callable callable = CodeFactory::ToString(isolate());
+          var_value.Bind(CallStub(callable, context, value));
+          Goto(&if_valueisstring);
+        }
+      }
+
+      Bind(&if_valueisnullorundefined);
+      {
+        // The {value} is either null or undefined.
+        CallRuntime(Runtime::kThrowCalledOnNullOrUndefined, context,
+                    HeapConstant(factory()->NewStringFromAsciiChecked(
+                        method_name, TENURED)));
+        Goto(&if_valueisstring);  // Never reached.
+      }
+    }
+  }
+  Bind(&if_valueissmi);
+  {
+    // The {value} is a Smi, convert it to a String.
+    Callable callable = CodeFactory::NumberToString(isolate());
+    var_value.Bind(CallStub(callable, context, value));
+    Goto(&if_valueisstring);
+  }
+  Bind(&if_valueisstring);
+  return var_value.value();
+}
+
+Node* CodeStubAssembler::StringCharCodeAt(Node* string, Node* index) {
+  // Translate the {index} into a Word.
+  index = SmiToWord(index);
+
+  // We may need to loop in case of cons or sliced strings.
+  Variable var_index(this, MachineType::PointerRepresentation());
+  Variable var_result(this, MachineRepresentation::kWord32);
+  Variable var_string(this, MachineRepresentation::kTagged);
+  Variable* loop_vars[] = {&var_index, &var_string};
+  Label done_loop(this, &var_result), loop(this, 2, loop_vars);
+  var_string.Bind(string);
+  var_index.Bind(index);
+  Goto(&loop);
+  Bind(&loop);
+  {
+    // Load the current {index}.
+    index = var_index.value();
+
+    // Load the current {string}.
+    string = var_string.value();
+
+    // Load the instance type of the {string}.
+    Node* string_instance_type = LoadInstanceType(string);
+
+    // Check if the {string} is a SeqString.
+    Label if_stringissequential(this), if_stringisnotsequential(this);
+    Branch(Word32Equal(Word32And(string_instance_type,
+                                 Int32Constant(kStringRepresentationMask)),
+                       Int32Constant(kSeqStringTag)),
+           &if_stringissequential, &if_stringisnotsequential);
+
+    Bind(&if_stringissequential);
+    {
+      // Check if the {string} is a TwoByteSeqString or a OneByteSeqString.
+      Label if_stringistwobyte(this), if_stringisonebyte(this);
+      Branch(Word32Equal(Word32And(string_instance_type,
+                                   Int32Constant(kStringEncodingMask)),
+                         Int32Constant(kTwoByteStringTag)),
+             &if_stringistwobyte, &if_stringisonebyte);
+
+      Bind(&if_stringisonebyte);
+      {
+        var_result.Bind(
+            Load(MachineType::Uint8(), string,
+                 IntPtrAdd(index, IntPtrConstant(SeqOneByteString::kHeaderSize -
+                                                 kHeapObjectTag))));
+        Goto(&done_loop);
+      }
+
+      Bind(&if_stringistwobyte);
+      {
+        var_result.Bind(
+            Load(MachineType::Uint16(), string,
+                 IntPtrAdd(WordShl(index, IntPtrConstant(1)),
+                           IntPtrConstant(SeqTwoByteString::kHeaderSize -
+                                          kHeapObjectTag))));
+        Goto(&done_loop);
+      }
+    }
+
+    Bind(&if_stringisnotsequential);
+    {
+      // Check if the {string} is a ConsString.
+      Label if_stringiscons(this), if_stringisnotcons(this);
+      Branch(Word32Equal(Word32And(string_instance_type,
+                                   Int32Constant(kStringRepresentationMask)),
+                         Int32Constant(kConsStringTag)),
+             &if_stringiscons, &if_stringisnotcons);
+
+      Bind(&if_stringiscons);
+      {
+        // Check whether the right hand side is the empty string (i.e. if
+        // this is really a flat string in a cons string). If that is not
+        // the case we flatten the string first.
+        Label if_rhsisempty(this), if_rhsisnotempty(this, Label::kDeferred);
+        Node* rhs = LoadObjectField(string, ConsString::kSecondOffset);
+        Branch(WordEqual(rhs, EmptyStringConstant()), &if_rhsisempty,
+               &if_rhsisnotempty);
+
+        Bind(&if_rhsisempty);
+        {
+          // Just operate on the left hand side of the {string}.
+          var_string.Bind(LoadObjectField(string, ConsString::kFirstOffset));
+          Goto(&loop);
+        }
+
+        Bind(&if_rhsisnotempty);
+        {
+          // Flatten the {string} and lookup in the resulting string.
+          var_string.Bind(CallRuntime(Runtime::kFlattenString,
+                                      NoContextConstant(), string));
+          Goto(&loop);
+        }
+      }
+
+      Bind(&if_stringisnotcons);
+      {
+        // Check if the {string} is an ExternalString.
+        Label if_stringisexternal(this), if_stringisnotexternal(this);
+        Branch(Word32Equal(Word32And(string_instance_type,
+                                     Int32Constant(kStringRepresentationMask)),
+                           Int32Constant(kExternalStringTag)),
+               &if_stringisexternal, &if_stringisnotexternal);
+
+        Bind(&if_stringisexternal);
+        {
+          // Check if the {string} is a short external string.
+          Label if_stringisshort(this),
+              if_stringisnotshort(this, Label::kDeferred);
+          Branch(Word32Equal(Word32And(string_instance_type,
+                                       Int32Constant(kShortExternalStringMask)),
+                             Int32Constant(0)),
+                 &if_stringisshort, &if_stringisnotshort);

[Igor Sheludko, 2016/09/28 16:00:23]

DBC: These label names are not in sync with the shortness definition (see
ExternalString::is_short()).

+
+          Bind(&if_stringisshort);
+          {
+            // Load the actual resource data from the {string}.
+            Node* string_resource_data =
+                LoadObjectField(string, ExternalString::kResourceDataOffset,
+                                MachineType::Pointer());
+
+            // Check if the {string} is a TwoByteExternalString or a
+            // OneByteExternalString.
+            Label if_stringistwobyte(this), if_stringisonebyte(this);
+            Branch(Word32Equal(Word32And(string_instance_type,
+                                         Int32Constant(kStringEncodingMask)),
+                               Int32Constant(kTwoByteStringTag)),
+                   &if_stringistwobyte, &if_stringisonebyte);
+
+            Bind(&if_stringisonebyte);
+            {
+              var_result.Bind(
+                  Load(MachineType::Uint8(), string_resource_data, index));
+              Goto(&done_loop);
+            }
+
+            Bind(&if_stringistwobyte);
+            {
+              var_result.Bind(Load(MachineType::Uint16(), string_resource_data,
+                                   WordShl(index, IntPtrConstant(1))));
+              Goto(&done_loop);
+            }
+          }
+
+          Bind(&if_stringisnotshort);
+          {
+            // The {string} might be compressed, call the runtime.
+            var_result.Bind(SmiToWord32(
+                CallRuntime(Runtime::kExternalStringGetChar,
+                            NoContextConstant(), string, SmiTag(index))));
+            Goto(&done_loop);
+          }
+        }
+
+        Bind(&if_stringisnotexternal);
+        {
+          // The {string} is a SlicedString, continue with its parent.
+          Node* string_offset =
+              SmiToWord(LoadObjectField(string, SlicedString::kOffsetOffset));
+          Node* string_parent =
+              LoadObjectField(string, SlicedString::kParentOffset);
+          var_index.Bind(IntPtrAdd(index, string_offset));
+          var_string.Bind(string_parent);
+          Goto(&loop);
+        }
+      }
+    }
+  }
+
+  Bind(&done_loop);
+  return var_result.value();
+}
+
+Node* CodeStubAssembler::StringFromCharCode(Node* code) {
+  Variable var_result(this, MachineRepresentation::kTagged);
+
+  // Check if the {code} is a one-byte char code.
+  Label if_codeisonebyte(this), if_codeistwobyte(this, Label::kDeferred),
+      if_done(this);
+  Branch(Int32LessThanOrEqual(code, Int32Constant(String::kMaxOneByteCharCode)),
+         &if_codeisonebyte, &if_codeistwobyte);
+  Bind(&if_codeisonebyte);
+  {
+    // Load the isolate wide single character string cache.
+    Node* cache = LoadRoot(Heap::kSingleCharacterStringCacheRootIndex);
+
+    // Check if we have an entry for the {code} in the single character string
+    // cache already.
+    Label if_entryisundefined(this, Label::kDeferred),
+        if_entryisnotundefined(this);
+    Node* entry = LoadFixedArrayElementInt32Index(cache, code);
+    Branch(WordEqual(entry, UndefinedConstant()), &if_entryisundefined,
+           &if_entryisnotundefined);
+
+    Bind(&if_entryisundefined);
+    {
+      // Allocate a new SeqOneByteString for {code} and store it in the {cache}.
+      Node* result = AllocateSeqOneByteString(1);
+      StoreNoWriteBarrier(
+          MachineRepresentation::kWord8, result,
+          IntPtrConstant(SeqOneByteString::kHeaderSize - kHeapObjectTag), code);
+      StoreFixedArrayElementInt32Index(cache, code, result);
+      var_result.Bind(result);
+      Goto(&if_done);
+    }
+
+    Bind(&if_entryisnotundefined);
+    {
+      // Return the entry from the {cache}.
+      var_result.Bind(entry);
+      Goto(&if_done);
+    }
+  }
+
+  Bind(&if_codeistwobyte);
+  {
+    // Allocate a new SeqTwoByteString for {code}.
+    Node* result = AllocateSeqTwoByteString(1);
+    StoreNoWriteBarrier(
+        MachineRepresentation::kWord16, result,
+        IntPtrConstant(SeqTwoByteString::kHeaderSize - kHeapObjectTag), code);
+    var_result.Bind(result);
+    Goto(&if_done);
+  }
+
+  Bind(&if_done);
+  return var_result.value();
+}
+
 void CodeStubAssembler::BranchIf(Node* condition, Label* if_true,
                                  Label* if_false) {
   Label if_condition_is_true(this), if_condition_is_false(this);