Use big-boy Types to annotate interface descriptor parameters

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/base/flags.h"
 #include "src/bootstrapper.h"
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/node.h"
 #include "src/compiler/node-properties.h"
@@ skipping 158 matching lines @@
 class Typer::Decorator final : public GraphDecorator {
  public:
   explicit Decorator(Typer* typer) : typer_(typer) {}
   void Decorate(Node* node) final;
 
  private:
   Typer* typer_;
 };
 
 
-Typer::Typer(Isolate* isolate, Graph* graph, MaybeHandle<Context> context)
+Typer::Typer(Isolate* isolate, Graph* graph, Type::FunctionType* function_type,
+             MaybeHandle<Context> context)
     : isolate_(isolate),
       graph_(graph),
+      function_type_(function_type),
       context_(context),
       decorator_(NULL),
       cache_(new (graph->zone()) LazyTypeCache(isolate, graph->zone())) {
   Zone* zone = this->zone();
   Factory* const factory = isolate->factory();
 
   Type* infinity = Type::Constant(factory->infinity_value(), zone);
   Type* minus_infinity = Type::Constant(factory->minus_infinity_value(), zone);
   Type* truncating_to_zero =
       Type::Union(Type::Union(infinity, minus_infinity, zone),
@@ skipping 435 matching lines @@
 
 Bounds Typer::Visitor::TypeIfException(Node* node) {
   return Bounds::Unbounded(zone());
 }
 
 
 // Common operators.
 
 
 Bounds Typer::Visitor::TypeParameter(Node* node) {
+  int param = OpParameter<int>(node);
+  Type::FunctionType* function_type = typer_->function_type();
+  if (function_type != nullptr && param >= 0 &&
+      param < static_cast<int>(function_type->Arity())) {
+    return Bounds(Type::None(), function_type->Parameter(param));
+  }
   return Bounds::Unbounded(zone());
 }
 
 
 Bounds Typer::Visitor::TypeOsrValue(Node* node) {
   if (node->InputAt(0)->opcode() == IrOpcode::kOsrLoopEntry) {
     // Before deconstruction, OSR values have type {None} to avoid polluting
     // the types of phis and other nodes in the graph.
     return Bounds(Type::None(), Type::None());
   }
@@ skipping 1774 matching lines @@
       TYPED_ARRAYS(TYPED_ARRAY_CASE)
 #undef TYPED_ARRAY_CASE
     }
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8