Compress deopt instructions in memory using variable length encoding.

runtime/vm/deopt_instructions.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_DEOPT_INSTRUCTIONS_H_
 #define VM_DEOPT_INSTRUCTIONS_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
@@ skipping 80 matching lines @@
   intptr_t source_frame_size() const { return source_frame_size_; }
   intptr_t dest_frame_size() const { return dest_frame_size_; }
 
   RawCode* code() const { return code_; }
 
   ICData::DeoptReasonId deopt_reason() const { return deopt_reason_; }
   bool HasDeoptFlag(ICData::DeoptFlags flag) {
     return (deopt_flags_ & flag) != 0;
   }
 
-  RawDeoptInfo* deopt_info() const { return deopt_info_; }
+  RawTypedData* deopt_info() const { return deopt_info_; }
 
   // Fills the destination frame but defers materialization of
   // objects.
   void FillDestFrame();
 
   // Materializes all deferred objects.  Returns the total number of
   // artificial arguments used during deoptimization.
   intptr_t MaterializeDeferredObjects();
 
   RawArray* DestFrameAsArray();
@@ skipping 87 matching lines @@
   void SetDeferredObjectAt(intptr_t idx, DeferredObject* object) {
     deferred_objects_[idx] = object;
   }
 
   intptr_t DeferredObjectsCount() const {
     return deferred_objects_count_;
   }
 
   RawCode* code_;
   RawArray* object_table_;
-  RawDeoptInfo* deopt_info_;
+  RawTypedData* deopt_info_;
   bool dest_frame_is_allocated_;
   intptr_t* dest_frame_;
   intptr_t dest_frame_size_;
   bool source_frame_is_allocated_;
   intptr_t* source_frame_;
   intptr_t source_frame_size_;
   intptr_t* cpu_registers_;
   fpu_register_t* fpu_registers_;
   intptr_t num_args_;
   ICData::DeoptReasonId deopt_reason_;
@@ skipping 30 matching lines @@
     kMintPair,
     // Mints are held in one word on 64-bit architectures.
     kMint,
     kInt32,
     kUint32,
     kPcMarker,
     kPp,
     kCallerFp,
     kCallerPp,
     kCallerPc,
-    kSuffix,
     kMaterializedObjectRef,
     kMaterializeObject
   };
 
   static DeoptInstr* Create(intptr_t kind_as_int, intptr_t source_index);
 
   DeoptInstr() {}
   virtual ~DeoptInstr() {}
 
   virtual const char* ToCString() const {
     const char* args = ArgumentsToCString();
     if (args != NULL) {
       return Thread::Current()->zone()->PrintToString(
           "%s(%s)", KindToCString(kind()), args);
     } else {
       return KindToCString(kind());
     }
   }
 
   virtual void Execute(DeoptContext* deopt_context, intptr_t* dest_addr) = 0;
 
   virtual DeoptInstr::Kind kind() const = 0;
 
   bool Equals(const DeoptInstr& other) const {
     return (kind() == other.kind()) && (source_index() == other.source_index());
   }
 
-  // Decode the payload of a suffix command.  Return the suffix length and
-  // set the output parameter info_number to the index of the shared suffix.
-  static intptr_t DecodeSuffix(intptr_t source_index, intptr_t* info_number);
-
   // Get the code and return address which is encoded in this
   // kRetAfterAddress deopt instruction.
   static uword GetRetAddress(DeoptInstr* instr,
                              const Array& object_table,
                              Code* code);
 
   // Return number of initialized fields in the object that will be
   // materialized by kMaterializeObject instruction.
   static intptr_t GetFieldCount(DeoptInstr* instr) {
     ASSERT(instr->kind() == DeoptInstr::kMaterializeObject);
@@ skipping 148 matching lines @@
   // for materialization: class of the instance to allocate and field-value
   // pairs for initialization.
   // Emitted instructions are expected to follow fixed size section of frame
   // emitted first. This way they become a part of the bottom-most deoptimized
   // frame and are discoverable by GC.
   // At deoptimization they will be removed by the stub at the very end:
   // after they were used to materialize objects.
   // Returns the index of the next stack slot. Used for verification.
   intptr_t EmitMaterializationArguments(intptr_t dest_index);
 
-  RawDeoptInfo* CreateDeoptInfo(const Array& deopt_table);
+  RawTypedData* CreateDeoptInfo(const Array& deopt_table);
 
   // Mark the actual start of the frame description after all materialization
   // instructions were emitted. Used for verification purposes.
   void MarkFrameStart() {
     ASSERT(frame_start_ == -1);
     frame_start_ = instructions_.length();
   }
 
  private:
   friend class CompilerDeoptInfo;  // For current_info_number_.
@@ skipping 30 matching lines @@
   GrowableArray<MaterializeObjectInstr*> materializations_;
 
   DISALLOW_COPY_AND_ASSIGN(DeoptInfoBuilder);
 };
 
 
 // Utilities for managing the deopt table and its entries.  The table is
 // stored in an Array in the heap.  It consists of triples of (PC offset,
 // info, reason).  Elements of each entry are stored consecutively in the
 // array.
+// TODO(vegorov): consider compressing the whole table into a single TypedData
+// object.
 class DeoptTable : public AllStatic {
  public:
   // Return the array size in elements for a given number of table entries.
   static intptr_t SizeFor(intptr_t length);
 
   // Set the entry at the given index into the table (not an array index).
   static void SetEntry(const Array& table,
                        intptr_t index,
                        const Smi& offset,
-                       const DeoptInfo& info,
+                       const TypedData& info,
                        const Smi& reason_and_flags);
 
   // Return the length of the table in entries.
   static intptr_t GetLength(const Array& table);
 
   // Set the output parameters (offset, info, reason) to the entry values at
   // the index into the table (not an array index).
   static void GetEntry(const Array& table,
                        intptr_t index,
                        Smi* offset,
-                       DeoptInfo* info,
+                       TypedData* info,
                        Smi* reason_and_flags);
 
   static RawSmi* EncodeReasonAndFlags(ICData::DeoptReasonId reason,
                                       uint32_t flags) {
     return Smi::New(ReasonField::encode(reason) |
                     FlagsField::encode(flags));
   }
 
   class ReasonField : public BitField<ICData::DeoptReasonId, 0, 8> { };
   class FlagsField : public BitField<uint32_t, 8, 8> { };
 
  private:
   static const intptr_t kEntrySize = 3;
 };
 
 }  // namespace dart
 
 #endif  // VM_DEOPT_INSTRUCTIONS_H_