[turbofan] Address a couple of Type-related TODOs.

src/compiler/typer.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/typer.h"
 
 #include <iomanip>
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
@@ skipping 1455 matching lines @@
 
 
 Type* Typer::Visitor::TypeJSForInNext(Node* node) {
   return Type::Union(Type::Name(), Type::Undefined(), zone());
 }
 
 
 Type* Typer::Visitor::TypeJSForInPrepare(Node* node) {
   STATIC_ASSERT(Map::EnumLengthBits::kMax <= FixedArray::kMaxLength);
   Type* const cache_type =
-      Type::Union(typer_->cache_.kSmi, Type::OtherInternal(), zone());
+      Type::Union(Type::SignedSmall(), Type::OtherInternal(), zone());
   Type* const cache_array = Type::OtherInternal();
   Type* const cache_length = typer_->cache_.kFixedArrayLengthType;
   return Type::Tuple(cache_type, cache_array, cache_length, zone());
 }
 
 
 Type* Typer::Visitor::TypeJSLoadMessage(Node* node) { return Type::Any(); }
 
 
 Type* Typer::Visitor::TypeJSStoreMessage(Node* node) {
   UNREACHABLE();
   return nullptr;
 }
 
 Type* Typer::Visitor::TypeJSGeneratorStore(Node* node) {
   UNREACHABLE();
   return nullptr;
 }
 
 Type* Typer::Visitor::TypeJSGeneratorRestoreContinuation(Node* node) {
-  return typer_->cache_.kSmi;
+  return Type::SignedSmall();
 }
 
 Type* Typer::Visitor::TypeJSGeneratorRestoreRegister(Node* node) {
   return Type::Any();
 }
 
 Type* Typer::Visitor::TypeJSStackCheck(Node* node) { return Type::Any(); }
 
 // Simplified operators.
 
@@ skipping 54 matching lines @@
 
 Type* Typer::Visitor::StringFromCharCodeTyper(Type* type, Typer* t) {
   return Type::String();
 }
 
 Type* Typer::Visitor::StringFromCodePointTyper(Type* type, Typer* t) {
   return Type::String();
 }
 
 Type* Typer::Visitor::TypeStringCharCodeAt(Node* node) {
-  // TODO(bmeurer): We could do better here based on inputs.
-  return Type::Range(0, kMaxUInt16, zone());
+  return typer_->cache_.kUint16;
 }
 
 Type* Typer::Visitor::TypeStringFromCharCode(Node* node) {
   return TypeUnaryOp(node, StringFromCharCodeTyper);
 }
 
 Type* Typer::Visitor::TypeStringFromCodePoint(Node* node) {
   return TypeUnaryOp(node, StringFromCodePointTyper);
 }
 
@@ skipping 59 matching lines @@
   return type;
 }
 
 Type* Typer::Visitor::TypeAllocate(Node* node) { return Type::Any(); }
 
 Type* Typer::Visitor::TypeLoadField(Node* node) {
   return FieldAccessOf(node->op()).type;
 }
 
 Type* Typer::Visitor::TypeLoadBuffer(Node* node) {
-  // TODO(bmeurer): This typing is not yet correct. Since we can still access
-  // out of bounds, the type in the general case has to include Undefined.
   switch (BufferAccessOf(node->op()).external_array_type()) {
 #define TYPED_ARRAY_CASE(ElemType, type, TYPE, ctype, size) \
   case kExternal##ElemType##Array:                          \
     return Type::Union(typer_->cache_.k##ElemType, Type::Undefined(), zone());
     TYPED_ARRAYS(TYPED_ARRAY_CASE)
 #undef TYPED_ARRAY_CASE
   }
   UNREACHABLE();
   return nullptr;
 }
@@ skipping 72 matching lines @@
 Type* Typer::Visitor::TypeConstant(Handle<Object> value) {
   if (Type::IsInteger(*value)) {
     return Type::Range(value->Number(), value->Number(), zone());
   }
   return Type::NewConstant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8