src: remove support for Smi string lengths

This is unused in all supported release branches.

Author: kvakil

src/llv8-constants.cc

@@ -286,12 +286,7 @@ void String::Load() {
   kExternalStringTag = LoadConstant("ExternalStringTag");
   kThinStringTag = LoadConstant("ThinStringTag");
 
-  kLengthIsSmi = true;
-  kLengthOffset = LoadConstant("class_String__length__SMI");
-  if (kLengthOffset == -1) {
-    kLengthIsSmi = false;
-    kLengthOffset = LoadConstant("class_String__length__int32_t");
-  }
+  kLengthOffset = LoadConstant("class_String__length__int32_t");
 }
 
 

src/llv8-constants.h

@@ -265,7 +265,6 @@ class String : public Module {
   int64_t kThinStringTag;
 
   int64_t kLengthOffset;
-  bool kLengthIsSmi;
 
  protected:
   void Load();

src/llv8-inl.h

@@ -456,13 +456,6 @@ inline int64_t String::Encoding(Error& err) {
 inline CheckedType<int32_t> String::Length(Error& err) {
   RETURN_IF_INVALID((*this), CheckedType<int32_t>());
 
-  if (v8()->string()->kLengthIsSmi) {
-    Smi len = LoadFieldValue<Smi>(v8()->string()->kLengthOffset, err);
-    RETURN_IF_INVALID(len, CheckedType<int32_t>());
-
-    return CheckedType<int32_t>(len.GetValue());
-  }
-
   CheckedType<int32_t> len = v8()->LoadValue<CheckedType<int32_t>>(
       LeaField(v8()->string()->kLengthOffset));
   RETURN_IF_INVALID(len, CheckedType<int32_t>());