Support for taking full snapshots from 'dart', not just 'dart_bootstrap'.

runtime/vm/symbols.cc

 // Copyright (c) 2012, 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/symbols.h"
 
 #include "vm/handles.h"
 #include "vm/handles_impl.h"
 #include "vm/hash_table.h"
 #include "vm/isolate.h"
@@ skipping 289 matching lines @@
     ASSERT(str->HasHash());
     ASSERT(str->IsCanonical());
     predefined_[c] = str->raw();
     symbol_handles_[idx] = str;
   }
 
   vm_isolate->object_store()->set_symbol_table(table.Release());
 }
 
 
-void Symbols::AddPredefinedSymbolsToIsolate() {
-  // Should only be run by regular Dart isolates.
-  Thread* thread = Thread::Current();
-  Isolate* isolate = thread->isolate();
-  Zone* zone = thread->zone();
-  ASSERT(isolate != Dart::vm_isolate());
-  String& str = String::Handle(zone);
-
-  SymbolTable table(zone, isolate->object_store()->symbol_table());
-
-  // Set up all the predefined string symbols and create symbols for
-  // language keywords.
-  for (intptr_t i = 1; i < Symbols::kNullCharId; i++) {
-    str = OneByteString::New(names[i], Heap::kOld);
-    str.Hash();
-    str ^= table.InsertOrGet(str);
-    str.SetCanonical();  // Make canonical once entered.
-  }
-
-  // Add Latin1 characters as Symbols, so that Symbols::FromCharCode is fast.
-  for (intptr_t c = 0; c < kNumberOfOneCharCodeSymbols; c++) {
-    intptr_t idx = (kNullCharId + c);
-    ASSERT(idx < kMaxPredefinedId);
-    ASSERT(Utf::IsLatin1(c));
-    uint8_t ch = static_cast<uint8_t>(c);
-    str = OneByteString::New(&ch, 1, Heap::kOld);
-    str.Hash();
-    str ^= table.InsertOrGet(str);
-    str.SetCanonical();  // Make canonical once entered.
-  }
-
-  isolate->object_store()->set_symbol_table(table.Release());
-}
-
-
 void Symbols::SetupSymbolTable(Isolate* isolate) {
   ASSERT(isolate != NULL);
 
   // Setup the symbol table used within the String class.
   const intptr_t initial_size = (isolate == Dart::vm_isolate()) ?
       kInitialVMIsolateSymtabSize : kInitialSymtabSize;
   Array& array =
       Array::Handle(HashTables::New<SymbolTable>(initial_size, Heap::kOld));
   isolate->object_store()->set_symbol_table(array);
 }
 
 
+RawArray* Symbols::UnifiedSymbolTable() {

[siva, 2016/05/05 00:50:05]

ASSERT that this should only be called by the mutator thread and the background
compiler thread is stopped at this point.

[rmacnak, 2016/05/05 20:40:57]

Done.

+  Thread* thread = Thread::Current();
+  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
+  SymbolTable vm_table(zone,
+                       Dart::vm_isolate()->object_store()->symbol_table());
+  SymbolTable table(zone, isolate->object_store()->symbol_table());
+  intptr_t unified_size = vm_table.NumOccupied() + table.NumOccupied();
+  SymbolTable unified_table(zone, HashTables::New<SymbolTable>(unified_size,
+                                                               Heap::kOld));
+  String& symbol = String::Handle(zone);
+
+  SymbolTable::Iterator vm_iter(&vm_table);
+  while (vm_iter.MoveNext()) {
+    symbol ^= vm_table.GetKey(vm_iter.Current());
+    ASSERT(!symbol.IsNull());
+    bool present = unified_table.Insert(symbol);
+    ASSERT(!present);
+  }
+  vm_table.Release();
+
+  SymbolTable::Iterator iter(&table);
+  while (iter.MoveNext()) {
+    symbol ^= table.GetKey(iter.Current());
+    ASSERT(!symbol.IsNull());
+    bool present = unified_table.Insert(symbol);
+    ASSERT(!present);
+  }
+  table.Release();
+
+  return unified_table.Release().raw();
+}
+
+
+#if defined(DART_PRECOMPILER)
 intptr_t Symbols::Compact(Isolate* isolate) {
   ASSERT(isolate != Dart::vm_isolate());
 
   Zone* zone = Thread::Current()->zone();
   intptr_t initial_size = -1;
   intptr_t final_size = -1;
 
-  // 1. Build a collection of all the predefined symbols so they are
-  // strongly referenced (the read only handles are not traced).
   {
     SymbolTable table(zone, isolate->object_store()->symbol_table());
     initial_size = table.NumOccupied();
-
-    if (Object::vm_isolate_snapshot_object_table().Length() == 0) {
-      GrowableObjectArray& predefined_symbols = GrowableObjectArray::Handle(
-          GrowableObjectArray::New(kMaxPredefinedId));
-      String& symbol = String::Handle();
-      for (intptr_t i = 1; i < Symbols::kNullCharId; i++) {
-        const unsigned char* name =
-          reinterpret_cast<const unsigned char*>(names[i]);
-        symbol ^= table.GetOrNull(Latin1Array(name, strlen(names[i])));
-        ASSERT(!symbol.IsNull());
-        predefined_symbols.Add(symbol);
-      }
-      for (intptr_t c = 0; c < kNumberOfOneCharCodeSymbols; c++) {
-        intptr_t idx = (kNullCharId + c);
-        ASSERT(idx < kMaxPredefinedId);
-        ASSERT(Utf::IsLatin1(c));
-        uint8_t ch = static_cast<uint8_t>(c);
-        symbol ^= table.GetOrNull(Latin1Array(&ch, 1));
-        ASSERT(!symbol.IsNull());
-        predefined_symbols.Add(symbol);
-      }
-    }
     table.Release();
   }

[siva, 2016/05/05 00:50:05]

This size computation seems to be needed only if FLAG_trace_compiler is  used,
can this code here be made conditional under that flag too.

[rmacnak, 2016/05/05 20:40:57]

Pushed to precompiler.cc

 
-  // 2. Knock out the symbol table and do a full garbage collection.
+  // 1. Drop the symbol table and do a full garbage collection.
   isolate->object_store()->set_symbol_table(Object::empty_array());
   isolate->heap()->CollectAllGarbage();
 
-  // 3. Walk the heap and build a new table from surviving symbols.
+  // 2. Walk the heap to find surviving symbols.
   GrowableArray<String*> symbols;
   class SymbolCollector : public ObjectVisitor {
    public:
     SymbolCollector(Thread* thread,
                     GrowableArray<String*>* symbols)
         : symbols_(symbols),
           zone_(thread->zone()) {}
 
     void VisitObject(RawObject* obj) {
       if (obj->IsString() && obj->IsCanonical()) {
         symbols_->Add(&String::ZoneHandle(zone_, String::RawCast(obj)));
       }
     }
 
    private:
     GrowableArray<String*>* symbols_;
     Zone* zone_;
   };
 
   SymbolCollector visitor(Thread::Current(), &symbols);
   isolate->heap()->IterateObjects(&visitor);
 
+  // 3. Build a new table from the surviving symbols.
   {
     Array& array =
         Array::Handle(HashTables::New<SymbolTable>(symbols.length() * 4 / 3,
                                                    Heap::kOld));
     SymbolTable table(zone, array.raw());
     for (intptr_t i = 0; i < symbols.length(); i++) {
       String& symbol = *symbols[i];
       ASSERT(symbol.IsString());
       ASSERT(symbol.IsCanonical());
       bool present = table.Insert(symbol);
       ASSERT(!present);
     }
+    isolate->object_store()->set_symbol_table(table.Release());
+  }
+
+  {
+    SymbolTable table(zone, isolate->object_store()->symbol_table());
     final_size = table.NumOccupied();
-    isolate->object_store()->set_symbol_table(table.Release());
+    table.Release();
   }

[siva, 2016/05/05 00:50:05]

Ditto comment about this size computation, probably only needed under a flag.

 
   return initial_size - final_size;
 }
+#endif   // DART_PRECOMPILER
 
 
 void Symbols::GetStats(Isolate* isolate, intptr_t* size, intptr_t* capacity) {
   ASSERT(isolate != NULL);
   SymbolTable table(isolate->object_store()->symbol_table());
   *size = table.NumOccupied();
   *capacity = table.NumEntries();
   table.Release();
 }
 
@@ skipping 199 matching lines @@
     table.Release();
   }
   if (symbol.IsNull()) {
     Isolate* isolate = thread->isolate();
     SafepointMutexLocker ml(isolate->symbols_mutex());
     data ^= isolate->object_store()->symbol_table();
     SymbolTable table(&key, &value, &data);
     symbol ^= table.GetOrNull(str);
     table.Release();
   }
-
   ASSERT(symbol.IsNull() || symbol.IsSymbol());
   ASSERT(symbol.IsNull() || symbol.HasHash());
   return symbol.raw();
 }
 
 
 RawString* Symbols::LookupFromConcat(
     Thread* thread, const String& str1, const String& str2) {
   if (str1.Length() == 0) {
     return Lookup(thread, str2);
@@ skipping 102 matching lines @@
 RawObject* Symbols::GetVMSymbol(intptr_t object_id) {
   ASSERT(IsVMSymbolId(object_id));
   intptr_t i = (object_id - kMaxPredefinedObjectIds);
   if ((i > kIllegal) && (i < Symbols::kMaxPredefinedId)) {
     return symbol_handles_[i]->raw();
   }
   return Object::null();
 }
 
 }  // namespace dart