[heap] Cleanup string factory methods a bit.

This is mostly removing dead code and also dropping MUST_USE_RESULT
annotations from methods that cannot throw an exception anyways.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/1370153002

Cr-Commit-Position: refs/heads/master@{#30995}

src/factory.cc

@@ -578,30 +578,10 @@ MaybeHandle<String> Factory::NewConsString(Handle<String> left,
             NewRawTwoByteString(length).ToHandleChecked(), left, right);
   }
 
-  return (is_one_byte || is_one_byte_data_in_two_byte_string)
-             ? NewOneByteConsString(length, left, right)
-             : NewTwoByteConsString(length, left, right);
-}
-
-
-MaybeHandle<String> Factory::NewOneByteConsString(int length,
-                                                  Handle<String> left,
-                                                  Handle<String> right) {
-  return NewRawConsString(cons_one_byte_string_map(), length, left, right);
-}
-
-
-MaybeHandle<String> Factory::NewTwoByteConsString(int length,
-                                                  Handle<String> left,
-                                                  Handle<String> right) {
-  return NewRawConsString(cons_string_map(), length, left, right);
-}
-
-
-MaybeHandle<String> Factory::NewRawConsString(Handle<Map> map, int length,
-                                              Handle<String> left,
-                                              Handle<String> right) {
-  Handle<ConsString> result = New<ConsString>(map, NEW_SPACE);
+  Handle<ConsString> result =
+      (is_one_byte || is_one_byte_data_in_two_byte_string)
+          ? New<ConsString>(cons_one_byte_string_map(), NEW_SPACE)
+          : New<ConsString>(cons_string_map(), NEW_SPACE);
 
   DisallowHeapAllocation no_gc;
   WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);

src/factory.h

@@ -156,24 +156,21 @@ class Factory final {
 
   // Allocates an internalized string in old space based on the character
   // stream.
-  MUST_USE_RESULT Handle<String> NewInternalizedStringFromUtf8(
-      Vector<const char> str,
-      int chars,
-      uint32_t hash_field);
+  Handle<String> NewInternalizedStringFromUtf8(Vector<const char> str,
+                                               int chars, uint32_t hash_field);
 
-  MUST_USE_RESULT Handle<String> NewOneByteInternalizedString(
-      Vector<const uint8_t> str, uint32_t hash_field);
+  Handle<String> NewOneByteInternalizedString(Vector<const uint8_t> str,
+                                              uint32_t hash_field);
 
-  MUST_USE_RESULT Handle<String> NewOneByteInternalizedSubString(
+  Handle<String> NewOneByteInternalizedSubString(
       Handle<SeqOneByteString> string, int offset, int length,
       uint32_t hash_field);
 
-  MUST_USE_RESULT Handle<String> NewTwoByteInternalizedString(
-        Vector<const uc16> str,
-        uint32_t hash_field);
+  Handle<String> NewTwoByteInternalizedString(Vector<const uc16> str,
+                                              uint32_t hash_field);
 
-  MUST_USE_RESULT Handle<String> NewInternalizedStringImpl(
-      Handle<String> string, int chars, uint32_t hash_field);
+  Handle<String> NewInternalizedStringImpl(Handle<String> string, int chars,
+                                           uint32_t hash_field);
 
   // Compute the matching internalized string map for a string if possible.
   // Empty handle is returned if string is in new space or not flattened.
@@ -197,14 +194,6 @@ class Factory final {
   // Create a new cons string object which consists of a pair of strings.
   MUST_USE_RESULT MaybeHandle<String> NewConsString(Handle<String> left,
                                                     Handle<String> right);
-  MUST_USE_RESULT MaybeHandle<String> NewOneByteConsString(
-      int length, Handle<String> left, Handle<String> right);
-  MUST_USE_RESULT MaybeHandle<String> NewTwoByteConsString(
-      int length, Handle<String> left, Handle<String> right);
-  MUST_USE_RESULT MaybeHandle<String> NewRawConsString(Handle<Map> map,
-                                                       int length,
-                                                       Handle<String> left,
-                                                       Handle<String> right);
 
   // Create a new string object which holds a proper substring of a string.
   Handle<String> NewProperSubString(Handle<String> str,

src/runtime/runtime-strings.cc

@@ -1158,28 +1158,6 @@ RUNTIME_FUNCTION(Runtime_NewString) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_NewConsString) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 4);
-  CONVERT_INT32_ARG_CHECKED(length, 0);
-  CONVERT_BOOLEAN_ARG_CHECKED(is_one_byte, 1);
-  CONVERT_ARG_HANDLE_CHECKED(String, left, 2);
-  CONVERT_ARG_HANDLE_CHECKED(String, right, 3);
-
-  Handle<String> result;
-  if (is_one_byte) {
-    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-        isolate, result,
-        isolate->factory()->NewOneByteConsString(length, left, right));
-  } else {
-    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-        isolate, result,
-        isolate->factory()->NewTwoByteConsString(length, left, right));
-  }
-  return *result;
-}
-
-
 RUNTIME_FUNCTION(Runtime_StringEquals) {
   HandleScope handle_scope(isolate);
   DCHECK(args.length() == 2);

src/runtime/runtime.h

@@ -915,7 +915,6 @@ namespace internal {
   F(StringTrim, 3, 1)                           \
   F(TruncateString, 2, 1)                       \
   F(NewString, 2, 1)                            \
-  F(NewConsString, 4, 1)                        \
   F(StringEquals, 2, 1)                         \
   F(FlattenString, 1, 1)                        \
   F(StringCharFromCode, 1, 1)                   \

test/cctest/compiler/test-run-intrinsics.cc

@@ -217,17 +217,6 @@ TEST(OneByteSeqStringSetChar) {
 }
 
 
-TEST(NewConsString) {
-  FunctionTester T(
-      "(function() { "
-      "   return %_NewConsString(14, true, 'abcdefghi', 'jklmn');"
-      " })",
-      flags);
-
-  T.CheckCall(T.Val("abcdefghijklmn"));
-}
-
-
 TEST(SetValueOf) {
   FunctionTester T("(function(a,b) { return %_SetValueOf(a,b); })", flags);