[stubs] Port StringAddStub to TF

In the process:
- Add ToString to the CodeStubAssembler and use it where appropriate
- Add constant-folding versions of IntPtrAdd/IntPtrSub to simplify code
  in element offset computation, especially for strings.

BUG=chromium:608675
LOG=N

Review-Url: https://codereview.chromium.org/2407813002
Cr-Commit-Position: refs/heads/master@{#40379}

src/builtins/builtins-conversion.cc

@@ -183,11 +183,7 @@ void Builtins::Generate_ToString(CodeStubAssembler* assembler) {
   }
 
   assembler->Bind(&is_number);
-  {
-    // TODO(tebbi): inline as soon as NumberToString is in the CodeStubAssembler
-    Callable callable = CodeFactory::NumberToString(assembler->isolate());
-    assembler->Return(assembler->CallStub(callable, context, input));
-  }
+  { assembler->Return(assembler->NumberToString(context, input)); }
 
   assembler->Bind(&not_heap_number);
   {

src/builtins/builtins-regexp.cc

@@ -1530,7 +1530,7 @@ compiler::Node* ReplaceFastPath(CodeStubAssembler* a, compiler::Node* context,
         Node* const second_part =
             a->SubString(context, subject_string, match_end, subject_end);
 
-        Node* const result = a->StringConcat(context, first_part, second_part);
+        Node* const result = a->StringAdd(context, first_part, second_part);
         var_result.Bind(result);
         a->Goto(&out);
       }
@@ -1543,8 +1543,8 @@ compiler::Node* ReplaceFastPath(CodeStubAssembler* a, compiler::Node* context,
         Node* const third_part =
             a->SubString(context, subject_string, match_end, subject_end);
 
-        Node* result = a->StringConcat(context, first_part, second_part);
-        result = a->StringConcat(context, result, third_part);
+        Node* result = a->StringAdd(context, first_part, second_part);
+        result = a->StringAdd(context, result, third_part);
 
         var_result.Bind(result);
         a->Goto(&out);

src/code-stub-assembler.h

@@ -104,6 +104,11 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
 
   compiler::Node* IntPtrOrSmiConstant(int value, ParameterMode mode);
 
+  compiler::Node* IntPtrAddFoldConstants(compiler::Node* left,
+                                         compiler::Node* right);
+  compiler::Node* IntPtrSubFoldConstants(compiler::Node* left,
+                                         compiler::Node* right);
+
   // Float64 operations.
   compiler::Node* Float64Ceil(compiler::Node* x);
   compiler::Node* Float64Floor(compiler::Node* x);
@@ -351,13 +356,17 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   compiler::Node* AllocateHeapNumberWithValue(compiler::Node* value,
                                               MutableMode mode = IMMUTABLE);
   // Allocate a SeqOneByteString with the given length.
-  compiler::Node* AllocateSeqOneByteString(int length);
-  compiler::Node* AllocateSeqOneByteString(compiler::Node* context,
-                                           compiler::Node* length);
+  compiler::Node* AllocateSeqOneByteString(int length,
+                                           AllocationFlags flags = kNone);
+  compiler::Node* AllocateSeqOneByteString(
+      compiler::Node* context, compiler::Node* length,
+      ParameterMode mode = INTPTR_PARAMETERS, AllocationFlags flags = kNone);
   // Allocate a SeqTwoByteString with the given length.
-  compiler::Node* AllocateSeqTwoByteString(int length);
-  compiler::Node* AllocateSeqTwoByteString(compiler::Node* context,
-                                           compiler::Node* length);
+  compiler::Node* AllocateSeqTwoByteString(int length,
+                                           AllocationFlags flags = kNone);
+  compiler::Node* AllocateSeqTwoByteString(
+      compiler::Node* context, compiler::Node* length,
+      ParameterMode mode = INTPTR_PARAMETERS, AllocationFlags flags = kNone);
 
   // Allocate a SlicedOneByteString with the given length, parent and offset.
   // |length| and |offset| are expected to be tagged.
@@ -375,13 +384,21 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   // expected to be one-byte strings.
   compiler::Node* AllocateOneByteConsString(compiler::Node* length,
                                             compiler::Node* first,
-                                            compiler::Node* second);
+                                            compiler::Node* second,
+                                            AllocationFlags flags = kNone);
   // Allocate a two-byte ConsString with the given length, first and second
   // parts. |length| is expected to be tagged, and |first| and |second| are
   // expected to be two-byte strings.
   compiler::Node* AllocateTwoByteConsString(compiler::Node* length,
                                             compiler::Node* first,
-                                            compiler::Node* second);
+                                            compiler::Node* second,
+                                            AllocationFlags flags = kNone);
+
+  // Allocate an appropriate one- or two-byte ConsString with the first and
+  // second parts specified by |first| and |second|.
+  compiler::Node* NewConsString(compiler::Node* context, compiler::Node* length,
+                                compiler::Node* left, compiler::Node* right,
+                                AllocationFlags flags = kNone);
 
   // Allocate a RegExpResult with the given length (the number of captures,
   // including the match itself), index (the index where the match starts),
@@ -456,16 +473,16 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   // Copies |character_count| elements from |from_string| to |to_string|
   // starting at the |from_index|'th character. |from_string| and |to_string|
   // must be either both one-byte strings or both two-byte strings.
-  // |from_index|, |to_index| and |character_count| must be Smis s.t.
-  // 0 <= |from_index| <= |from_index| + |character_count| <= from_string.length
-  // and
-  // 0 <= |to_index| <= |to_index| + |character_count| <= to_string.length.
+  // |from_index|, |to_index| and |character_count| must be either Smis or
+  // intptr_ts depending on |mode| s.t. 0 <= |from_index| <= |from_index| +
+  // |character_count| <= from_string.length and 0 <= |to_index| <= |to_index| +
+  // |character_count| <= to_string.length.
   void CopyStringCharacters(compiler::Node* from_string,
                             compiler::Node* to_string,
                             compiler::Node* from_index,
                             compiler::Node* to_index,
                             compiler::Node* character_count,
-                            String::Encoding encoding);
+                            String::Encoding encoding, ParameterMode mode);
 
   // Loads an element from |array| of |from_kind| elements by given |offset|
   // (NOTE: not index!), does a hole check if |if_hole| is provided and
@@ -555,8 +572,9 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                             compiler::Node* from, compiler::Node* to);
 
   // Return a new string object produced by concatenating |first| with |second|.
-  compiler::Node* StringConcat(compiler::Node* context, compiler::Node* first,
-                               compiler::Node* second);
+  compiler::Node* StringAdd(compiler::Node* context, compiler::Node* first,
+                            compiler::Node* second,
+                            AllocationFlags flags = kNone);
 
   // Return the first index >= {from} at which {needle_char} was found in
   // {string}, or -1 if such an index does not exist. The returned value is
@@ -584,6 +602,13 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   // Convert any object to a Number.
   compiler::Node* ToNumber(compiler::Node* context, compiler::Node* input);
 
+  // Convert any object to a String.
+  compiler::Node* ToString(compiler::Node* context, compiler::Node* input);
+
+  // Convert any object to a Primitive.
+  compiler::Node* JSReceiverToPrimitive(compiler::Node* context,
+                                        compiler::Node* input);
+
   enum ToIntegerTruncationMode {
     kNoTruncation,
     kTruncateMinusZero,
@@ -910,10 +935,16 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
       ParameterMode mode = INTPTR_PARAMETERS,
       ForEachDirection direction = ForEachDirection::kReverse);
 
+  compiler::Node* GetArrayAllocationSize(compiler::Node* element_count,
+                                         ElementsKind kind, ParameterMode mode,
+                                         int header_size) {
+    return ElementOffsetFromIndex(element_count, kind, mode, header_size);
+  }
+
   compiler::Node* GetFixedArrayAllocationSize(compiler::Node* element_count,
                                               ElementsKind kind,
                                               ParameterMode mode) {
-    return ElementOffsetFromIndex(element_count, kind, mode,
+    return GetArrayAllocationSize(element_count, kind, mode,
                                   FixedArray::kHeaderSize);
   }
 

src/code-stubs-hydrogen.cc

@@ -1120,34 +1120,6 @@ HValue* CodeStubGraphBuilderBase::BuildToPrimitive(HValue* input,
   return Pop();
 }
 
-
-template <>
-HValue* CodeStubGraphBuilder<StringAddStub>::BuildCodeInitializedStub() {
-  StringAddStub* stub = casted_stub();
-  StringAddFlags flags = stub->flags();
-  PretenureFlag pretenure_flag = stub->pretenure_flag();
-
-  HValue* left = GetParameter(Descriptor::kLeft);
-  HValue* right = GetParameter(Descriptor::kRight);
-
-  // Make sure that both arguments are strings if not known in advance.
-  if ((flags & STRING_ADD_CHECK_LEFT) == STRING_ADD_CHECK_LEFT) {
-    left =
-        BuildToString(left, (flags & STRING_ADD_CONVERT) == STRING_ADD_CONVERT);
-  }
-  if ((flags & STRING_ADD_CHECK_RIGHT) == STRING_ADD_CHECK_RIGHT) {
-    right = BuildToString(right,
-                          (flags & STRING_ADD_CONVERT) == STRING_ADD_CONVERT);
-  }
-
-  return BuildStringAdd(left, right, HAllocationMode(pretenure_flag));
-}
-
-
-Handle<Code> StringAddStub::GenerateCode() {
-  return DoGenerateCode(this);
-}
-
 template <>
 HValue* CodeStubGraphBuilder<ToBooleanICStub>::BuildCodeInitializedStub() {
   ToBooleanICStub* stub = casted_stub();

src/code-stubs.cc

@@ -345,6 +345,38 @@ void StringAddStub::PrintBaseName(std::ostream& os) const {  // NOLINT
   os << "StringAddStub_" << flags() << "_" << pretenure_flag();
 }
 
+void StringAddStub::GenerateAssembly(CodeStubAssembler* assembler) const {
+  typedef compiler::Node Node;
+  Node* left = assembler->Parameter(Descriptor::kLeft);
+  Node* right = assembler->Parameter(Descriptor::kRight);
+  Node* context = assembler->Parameter(Descriptor::kContext);
+
+  if ((flags() & STRING_ADD_CHECK_LEFT) != 0) {
+    DCHECK((flags() & STRING_ADD_CONVERT) != 0);
+    // TODO(danno): The ToString and JSReceiverToPrimitive below could be
+    // combined to avoid duplicate smi and instance type checks.
+    left = assembler->ToString(context,
+                               assembler->JSReceiverToPrimitive(context, left));
+  }
+  if ((flags() & STRING_ADD_CHECK_RIGHT) != 0) {
+    DCHECK((flags() & STRING_ADD_CONVERT) != 0);
+    // TODO(danno): The ToString and JSReceiverToPrimitive below could be
+    // combined to avoid duplicate smi and instance type checks.
+    right = assembler->ToString(
+        context, assembler->JSReceiverToPrimitive(context, right));
+  }
+
+  if ((flags() & STRING_ADD_CHECK_BOTH) == 0) {
+    CodeStubAssembler::AllocationFlag flags =
+        (pretenure_flag() == TENURED) ? CodeStubAssembler::kPretenured
+                                      : CodeStubAssembler::kNone;
+    assembler->Return(assembler->StringAdd(context, left, right, flags));
+  } else {
+    Callable callable = CodeFactory::StringAdd(isolate(), STRING_ADD_CHECK_NONE,
+                                               pretenure_flag());
+    assembler->TailCallStub(callable, context, left, right);
+  }
+}
 
 InlineCacheState CompareICStub::GetICState() const {
   CompareICState::State state = Max(left(), right());
@@ -2167,13 +2199,6 @@ void BinaryOpWithAllocationSiteStub::InitializeDescriptor(
       FUNCTION_ADDR(Runtime_BinaryOpIC_MissWithAllocationSite));
 }
 
-
-void StringAddStub::InitializeDescriptor(CodeStubDescriptor* descriptor) {
-  descriptor->Initialize(Runtime::FunctionForId(Runtime::kStringAdd)->entry);
-  descriptor->SetMissHandler(Runtime::kStringAdd);
-}
-
-
 void GetPropertyStub::GenerateAssembly(CodeStubAssembler* assembler) const {
   typedef compiler::Node Node;
   typedef CodeStubAssembler::Label Label;

src/code-stubs.h

@@ -60,7 +60,6 @@ class ObjectLiteral;
   V(CallICTrampoline)                         \
   V(KeyedStoreICTrampoline)                   \
   /* --- HydrogenCodeStubs --- */             \
-  V(StringAdd)                                \
   /* These builtins w/ JS linkage are */      \
   /* just fast-cases of C++ builtins. They */ \
   /* require varg support from TF */          \
@@ -119,6 +118,7 @@ class ObjectLiteral;
   V(LoadScriptContextField)                   \
   V(StoreScriptContextField)                  \
   V(NumberToString)                           \
+  V(StringAdd)                                \
   V(GetProperty)                              \
   V(LoadIC)                                   \
   V(KeyedLoadICTF)                            \
@@ -1610,22 +1610,21 @@ class BinaryOpWithAllocationSiteStub final : public BinaryOpICStub {
   DEFINE_HYDROGEN_CODE_STUB(BinaryOpWithAllocationSite, BinaryOpICStub);
 };
 
-
-class StringAddStub final : public HydrogenCodeStub {
+class StringAddStub final : public TurboFanCodeStub {
  public:
   StringAddStub(Isolate* isolate, StringAddFlags flags,
                 PretenureFlag pretenure_flag)
-      : HydrogenCodeStub(isolate) {
-    set_sub_minor_key(StringAddFlagsBits::encode(flags) |
-                      PretenureFlagBits::encode(pretenure_flag));
+      : TurboFanCodeStub(isolate) {
+    minor_key_ = (StringAddFlagsBits::encode(flags) |
+                  PretenureFlagBits::encode(pretenure_flag));
   }
 
   StringAddFlags flags() const {
-    return StringAddFlagsBits::decode(sub_minor_key());
+    return StringAddFlagsBits::decode(minor_key_);
   }
 
   PretenureFlag pretenure_flag() const {
-    return PretenureFlagBits::decode(sub_minor_key());
+    return PretenureFlagBits::decode(minor_key_);
   }
 
  private:
@@ -1635,7 +1634,7 @@ class StringAddStub final : public HydrogenCodeStub {
   void PrintBaseName(std::ostream& os) const override;  // NOLINT
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(StringAdd);
-  DEFINE_HYDROGEN_CODE_STUB(StringAdd, HydrogenCodeStub);
+  DEFINE_TURBOFAN_CODE_STUB(StringAdd, TurboFanCodeStub);
 };
 
 

src/compiler/code-assembler.cc

@@ -148,6 +148,20 @@ bool CodeAssembler::ToInt64Constant(Node* node, int64_t& out_value) {
   return m.HasValue();
 }
 
+bool CodeAssembler::ToSmiConstant(Node* node, Smi*& out_value) {
+  if (node->opcode() == IrOpcode::kBitcastWordToTaggedSigned) {
+    node = node->InputAt(0);
+  } else {
+    return false;
+  }
+  IntPtrMatcher m(node);
+  if (m.HasValue()) {
+    out_value = Smi::cast(bit_cast<Object*>(m.Value()));
+    return true;
+  }
+  return false;
+}
+
 bool CodeAssembler::ToIntPtrConstant(Node* node, intptr_t& out_value) {
   IntPtrMatcher m(node);
   if (m.HasValue()) out_value = m.Value();

src/compiler/code-assembler.h

@@ -229,6 +229,7 @@ class V8_EXPORT_PRIVATE CodeAssembler {
 
   bool ToInt32Constant(Node* node, int32_t& out_value);
   bool ToInt64Constant(Node* node, int64_t& out_value);
+  bool ToSmiConstant(Node* node, Smi*& out_value);
   bool ToIntPtrConstant(Node* node, intptr_t& out_value);
 
   Node* Parameter(int value);