Improve static type propagation.

runtime/vm/intermediate_language.h

 // 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.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1803 matching lines @@
   // Printing support.
   virtual void PrintTo(BufferFormatter* f) const = 0;
   virtual void PrintToVisualizer(BufferFormatter* f) const = 0;
 
 #define INSTRUCTION_TYPE_CHECK(type)                                           \
   virtual bool Is##type() const { return false; }                              \
   virtual type##Instr* As##type() { return NULL; }
 FOR_EACH_INSTRUCTION(INSTRUCTION_TYPE_CHECK)
 #undef INSTRUCTION_TYPE_CHECK
 
-  // Static type of the instruction.
-  virtual RawAbstractType* StaticType() const {
-    UNREACHABLE();
-    return AbstractType::null();
-  }
-
   // Returns structure describing location constraints required
   // to emit native code for this instruction.
   virtual LocationSummary* locs() {
     // TODO(vegorov): This should be pure virtual method.
     // However we are temporary using NULL for instructions that
     // were not converted to the location based code generation yet.
     return NULL;
   }
 
   virtual void EmitNativeCode(FlowGraphCompiler* compiler) {
@@ skipping 311 matching lines @@
   intptr_t temp_index() const { return temp_index_; }
   void set_temp_index(intptr_t index) { temp_index_ = index; }
 
   intptr_t ssa_temp_index() const { return ssa_temp_index_; }
   void set_ssa_temp_index(intptr_t index) {
     ASSERT(index >= 0);
     ssa_temp_index_ = index;
   }
   bool HasSSATemp() const { return ssa_temp_index_ >= 0; }
 
+  // Static type of the definition.
+  virtual RawAbstractType* StaticType() const = 0;
+
  private:
   intptr_t temp_index_;
   intptr_t ssa_temp_index_;
 
   DISALLOW_COPY_AND_ASSIGN(Definition);
 };
 
 
 Definition* UseVal::definition() const {
   // Check that the definition is either a Phi or a linked in the the IR.
@@ skipping 40 matching lines @@
 
 
 class PhiInstr : public Definition {
  public:
   explicit PhiInstr(intptr_t num_inputs) : inputs_(num_inputs) {
     for (intptr_t i = 0; i < num_inputs; ++i) {
       inputs_.Add(NULL);
     }
   }
 
+  // Least upper bound of the static types of the inputs.
+  virtual RawAbstractType* StaticType() const;
+
   DECLARE_INSTRUCTION(Phi)
 
  private:
   GrowableArray<Value*> inputs_;
 
   DISALLOW_COPY_AND_ASSIGN(PhiInstr);
 };
 
 
 class ParameterInstr : public Definition {
  public:
   explicit ParameterInstr(intptr_t index) : index_(index) { }
 
   intptr_t index() const { return index_; }
 
+  // Static type of the passed-in parameter.
+  virtual RawAbstractType* StaticType() const;
+
   DECLARE_INSTRUCTION(Parameter)
 
  private:
   const intptr_t index_;
 
   DISALLOW_COPY_AND_ASSIGN(ParameterInstr);
 };
 
 
 class PushArgumentInstr : public InstructionWithInputs {
@@ skipping 362 matching lines @@
   const GrowableArray<BlockEntryInstr*>& block_order_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_