Trace signature types in the tree shaker.

runtime/vm/precompiler.cc

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/precompiler.h"
 
 #include "vm/aot_optimizer.h"
 #include "vm/assembler.h"
 #include "vm/ast_printer.h"
 #include "vm/branch_optimizer.h"
@@ skipping 988 matching lines @@
   AddType(type);
 
   if (cls.IsTypedefClass()) {
     AddTypesOf(Function::Handle(Z, cls.signature_function()));
   }
 }
 
 
 void Precompiler::AddTypesOf(const Function& function) {
   if (function.IsNull()) return;
-  // We don't expect to see a reference to a redicting factory.
+  if (functions_to_retain_.HasKey(&function)) return;
+  // We don't expect to see a reference to a redirecting factory. Only its
+  // target should remain.
   ASSERT(!function.IsRedirectingFactory());
-  if (functions_to_retain_.HasKey(&function)) return;
   functions_to_retain_.Insert(&Function::ZoneHandle(Z, function.raw()));
 
   AbstractType& type = AbstractType::Handle(Z);
   type = function.result_type();
   AddType(type);
   for (intptr_t i = 0; i < function.NumParameters(); i++) {
     type = function.ParameterTypeAt(i);
     AddType(type);
   }
   Code& code = Code::Handle(Z, function.CurrentCode());
@@ skipping 12 matching lines @@
         }
       }
     }
   }
   // A function can always be inlined and have only a nested local function
   // remain.
   const Function& parent = Function::Handle(Z, function.parent_function());
   if (!parent.IsNull()) {
     AddTypesOf(parent);
   }
+  if (function.IsSignatureFunction() || function.IsClosureFunction()) {
+    type = function.ExistingSignatureType();
+    if (!type.IsNull()) {
+      AddType(type);
+    }
+  }
   // A class may have all functions inlined except a local function.
   const Class& owner = Class::Handle(Z, function.Owner());
   AddTypesOf(owner);
 }
 
 
 void Precompiler::AddType(const AbstractType& abstype) {
   if (abstype.IsNull()) return;
 
   if (types_to_retain_.HasKey(&abstype)) return;
@@ skipping 2274 matching lines @@
 
   ASSERT(FLAG_precompiled_mode);
   const bool optimized = function.IsOptimizable();  // False for natives.
   DartPrecompilationPipeline pipeline(zone, field_type_map);
   return PrecompileFunctionHelper(precompiler, &pipeline, function, optimized);
 }
 
 #endif  // DART_PRECOMPILER
 
 }  // namespace dart