[stubs] Port StringAddStub to TF

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index b5642d4badeaf3c73174e7788f1d37c2088c9108..625b8d8518daccb3f3115b726243cfdeea087ae4 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -101,6 +101,11 @@ class 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);
@@ -341,13 +346,17 @@ class 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(int length,
+                                           AllocationFlags flags = kNone);
   compiler::Node* AllocateSeqOneByteString(compiler::Node* context,
-                                           compiler::Node* length);
+                                           compiler::Node* length,
+                                           AllocationFlags flags = kNone);
   // Allocate a SeqTwoByteString with the given length.
-  compiler::Node* AllocateSeqTwoByteString(int length);
+  compiler::Node* AllocateSeqTwoByteString(int length,
+                                           AllocationFlags flags = kNone);
   compiler::Node* AllocateSeqTwoByteString(compiler::Node* context,
-                                           compiler::Node* length);
+                                           compiler::Node* length,
+                                           AllocationFlags flags = kNone);
 
   // Allocate a SlicedOneByteString with the given length, parent and offset.
   // |length| and |offset| are expected to be tagged.
@@ -444,7 +453,7 @@ class CodeStubAssembler : public compiler::CodeAssembler {
                             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
@@ -563,6 +572,13 @@ class 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,
@@ -572,6 +588,14 @@ class CodeStubAssembler : public compiler::CodeAssembler {
   compiler::Node* ToInteger(compiler::Node* context, compiler::Node* input,
                             ToIntegerTruncationMode mode = kNoTruncation);
 
+  compiler::Node* NewConsString(compiler::Node* context, compiler::Node* length,
+                                compiler::Node* left, compiler::Node* right,
+                                AllocationFlags flags = kNone);
+
+  compiler::Node* StringAdd(compiler::Node* context, compiler::Node* left,
+                            compiler::Node* right,
+                            AllocationFlags flags = kNone);
+
   // Returns a node that contains a decoded (unsigned!) value of a bit
   // field |T| in |word32|. Returns result as an uint32 node.
   template <typename T>