Runtime support for evaluation of static field initializer expressions

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 687 matching lines @@
   M(DropTemps)                                                                 \
   M(StoreLocal)                                                                \
   M(StrictCompare)                                                             \
   M(EqualityCompare)                                                           \
   M(RelationalOp)                                                              \
   M(NativeCall)                                                                \
   M(DebugStepCheck)                                                            \
   M(LoadIndexed)                                                               \
   M(StoreIndexed)                                                              \
   M(StoreInstanceField)                                                        \
+  M(InitStaticField)                                                           \
   M(LoadStaticField)                                                           \
   M(StoreStaticField)                                                          \
   M(BooleanNegate)                                                             \
   M(InstanceOf)                                                                \
   M(CreateArray)                                                               \
   M(AllocateObject)                                                            \
   M(LoadField)                                                                 \
   M(LoadUntagged)                                                              \
   M(LoadClassId)                                                               \
   M(InstantiateType)                                                           \
@@ skipping 3899 matching lines @@
   virtual bool MayThrow() const { return false; }
 
  private:
   const intptr_t token_pos_;
   const intptr_t num_context_variables_;
 
   DISALLOW_COPY_AND_ASSIGN(AllocateContextInstr);
 };
 
 
+class InitStaticFieldInstr : public TemplateInstruction<1> {
+ public:
+  InitStaticFieldInstr(Value* input, const Field& field)
+      : field_(field) {
+    SetInputAt(0, input);
+  }
+
+  virtual intptr_t token_pos() const { return field_.token_pos(); }
+  const Field& field() const { return field_; }
+
+  DECLARE_INSTRUCTION(InitStaticField)
+
+  virtual intptr_t ArgumentCount() const { return 0; }
+  virtual bool CanDeoptimize() const { return true; }

[srdjan, 2014/08/19 18:49:39]

Why can it deoptimize?

[hausner, 2014/08/19 20:54:00]

As discussed offline, the initializer expression can have side effects that
cause deoptimization.

+  virtual EffectSet Effects() const { return EffectSet::All(); }
+  virtual bool MayThrow() const { return true; }
+  virtual Instruction* Canonicalize(FlowGraph* flow_graph);
+
+ private:
+  const Field& field_;
+
+  DISALLOW_COPY_AND_ASSIGN(InitStaticFieldInstr);
+};
+
+
 class AllocateUninitializedContextInstr : public TemplateDefinition<0> {
  public:
   AllocateUninitializedContextInstr(intptr_t token_pos,
                                     intptr_t num_context_variables)
       : token_pos_(token_pos),
         num_context_variables_(num_context_variables) {}
 
   DECLARE_INSTRUCTION(AllocateUninitializedContext)
   virtual CompileType ComputeType() const;
 
@@ skipping 3730 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_