Precompilation: canonicalize lists of stackmaps.

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/cha.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
 #include "vm/hash_table.h"
@@ skipping 101 matching lines @@
   }
 
   DropUncompiledFunctions();
   DropFields();
 
   // TODO(rmacnak): DropEmptyClasses();
 
   BindStaticCalls();
 
   DedupStackmaps();
+  DedupStackmapLists();
 
   if (FLAG_trace_precompiler) {
     THR_Print("Precompiled %" Pd " functions, %" Pd " dynamic types,"
               " %" Pd " dynamic selectors.\n Dropped %" Pd " functions, %" Pd
               " fields.\n",
               function_count_,
               class_count_,
               selector_count_,
               dropped_function_count_,
               dropped_field_count_);
@@ skipping 969 matching lines @@
     Code& code_;
     Array& stackmaps_;
     Stackmap& stackmap_;
   };
 
   DedupStackmapsVisitor visitor(Z);
   VisitFunctions(&visitor);
 }
 
 
+void Precompiler::DedupStackmapLists() {
+  class DedupStackmapListsVisitor : public FunctionVisitor {
+   public:
+    explicit DedupStackmapListsVisitor(Zone* zone) :
+      zone_(zone),
+      canonical_stackmap_lists_(),
+      code_(Code::Handle(zone)),
+      stackmaps_(Array::Handle(zone)),
+      stackmap_(Stackmap::Handle(zone)) {
+    }
+
+    void VisitFunction(const Function& function) {
+      if (!function.HasCode()) {
+        ASSERT(function.HasImplicitClosureFunction());
+        return;
+      }
+      code_ = function.CurrentCode();
+      stackmaps_ = code_.stackmaps();
+      if (stackmaps_.IsNull()) return;
+
+      stackmaps_ = DedupStackmapList(stackmaps_);
+      code_.set_stackmaps(stackmaps_);
+    }
+
+    RawArray* DedupStackmapList(const Array& stackmaps) {
+      const Array* canonical_stackmap_list =
+          canonical_stackmap_lists_.Lookup(&stackmaps);
+      if (canonical_stackmap_list == NULL) {
+        canonical_stackmap_lists_.Insert(
+            &Array::ZoneHandle(zone_, stackmaps.raw()));
+        return stackmaps.raw();
+      } else {
+        return canonical_stackmap_list->raw();
+      }
+    }
+
+   private:
+    Zone* zone_;
+    ArraySet canonical_stackmap_lists_;
+    Code& code_;
+    Array& stackmaps_;
+    Stackmap& stackmap_;
+  };
+
+  DedupStackmapListsVisitor visitor(Z);
+  VisitFunctions(&visitor);
+}
+
+
 void Precompiler::VisitFunctions(FunctionVisitor* visitor) {
   Library& lib = Library::Handle(Z);
   Class& cls = Class::Handle(Z);
   Array& functions = Array::Handle(Z);
   Object& object = Object::Handle(Z);
   Function& function = Function::Handle(Z);
   GrowableObjectArray& closures = GrowableObjectArray::Handle(Z);
 
   for (intptr_t i = 0; i < libraries_.Length(); i++) {
     lib ^= libraries_.At(i);
@@ skipping 83 matching lines @@
       cls = it.GetNextClass();
       if (cls.IsDynamicClass()) {
         continue;  // class 'dynamic' is in the read-only VM isolate.
       }
       cls.set_is_allocated(false);
     }
   }
 }
 
 }  // namespace dart