Make stackmaps store their actual length.

runtime/vm/raw_object.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_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 #include "vm/token.h"
@@ skipping 748 matching lines @@
   RawLocalVarDescriptors* var_descriptors_;
   RawArray* comments_;
   RawObject** to() {
     return reinterpret_cast<RawObject**>(&ptr()->comments_);
   }
 
   intptr_t pointer_offsets_length_;
   // This cannot be boolean because of alignment issues on x64 architectures.
   intptr_t is_optimized_;
 
-  // The number of spill slots used by an optimized code object.  This is
-  // used as the length of each stackmap in the code.
-  intptr_t spill_slot_count_;
-
   // Variable length data follows here.
   int32_t data_[0];
 
   friend class StackFrame;
 };
 
 
 class RawInstructions : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Instructions);
 
@@ skipping 17 matching lines @@
 class RawPcDescriptors : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(PcDescriptors);
 
   RawSmi* length_;  // Number of descriptors.
 
   // Variable length data follows here.
   intptr_t data_[0];
 };
 
 
-// Stackmap is an immutable representation of the layout of the stack at
-// a PC. The stack map representation consists of a bit map which marks
-// each stack slot index starting from the FP (frame pointer) as an object
-// or regular untagged value.
-// The Stackmap also consists of a link to code object corresponding to
-// the frame which the stack map is describing.
-// The bit map representation is optimized for dense and small bit maps,
-// without any upper bound.
+// Stackmap is an immutable representation of the layout of the stack at a
+// PC. The stack map representation consists of a bit map which marks each
+// live object index starting from the base of the frame.
+//
+// The Stackmap also consists of a link to the code object corresponding to
+// the frame which the stack map is describing.  The bit map representation
+// is optimized for dense and small bit maps, without any upper bound.
 class RawStackmap : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Stackmap);
 
-  RawObject** from() {
-    return reinterpret_cast<RawObject**>(&ptr()->code_);
-  }
   RawCode* code_;  // Code object corresponding to the frame described.
-  RawSmi* bitmap_size_in_bytes_;  // Size of the bit map in bytes.
-  RawObject** to() {
-    return reinterpret_cast<RawObject**>(&ptr()->bitmap_size_in_bytes_);
-  }
+
+  intptr_t length_;  // Length of payload, in bits.
   uword pc_;  // PC corresponding to this stack map representation.
-  intptr_t min_set_bit_index_;  // Minimum bit offset which is set.
-  intptr_t max_set_bit_index_;  // Maximum bit offset which is set.
 
   // Variable length data follows here (bitmap of the stack layout).
   uint8_t data_[0];
 };
 
 
 class RawLocalVarDescriptors : public RawObject {
  public:
   enum VarInfoKind {
     kStackVar = 1,
@@ skipping 745 matching lines @@
          kExternalUint64ArrayCid == kByteArrayCid + 18 &&
          kExternalFloat32ArrayCid == kByteArrayCid + 19 &&
          kExternalFloat64ArrayCid == kByteArrayCid + 20 &&
          kStacktraceCid == kByteArrayCid + 21);
   return (index >= kByteArrayCid && index <= kExternalFloat64ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_