First step towards implementing stack map descriptions for the optimizing compiler.

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 17 matching lines @@
   V(Function)                                                                  \
   V(Field)                                                                     \
   V(LiteralToken)                                                              \
   V(TokenStream)                                                               \
   V(Script)                                                                    \
   V(Library)                                                                   \
   V(LibraryPrefix)                                                             \
   V(Code)                                                                      \
   V(Instructions)                                                              \
   V(PcDescriptors)                                                             \
+  V(Stackmap)                                                                  \
   V(LocalVarDescriptors)                                                       \
   V(ExceptionHandlers)                                                         \
   V(Context)                                                                   \
   V(ContextScope)                                                              \
   V(ICData)                                                                    \
   V(Error)                                                                     \
     V(ApiError)                                                                \
     V(LanguageError)                                                           \
     V(UnhandledException)                                                      \
     V(UnwindError)                                                             \
@@ skipping 633 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.
+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_);
+  }
+  uword pc_;  // PC corresponding to this stack map representation.
+
+  // Variable length data follows here (bitmap of the stack layout).
+  uint8_t data_[0];
+};
+
+
 class RawLocalVarDescriptors : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(LocalVarDescriptors);
 
   struct VarInfo {
     intptr_t index;      // Slot index on stack or in context.
     intptr_t scope_id;   // Scope to which the variable belongs.
     intptr_t begin_pos;  // Token position of scope start.
     intptr_t end_pos;    // Token position of scope end.
   };
 
@@ skipping 431 matching lines @@
     return reinterpret_cast<RawObject**>(&ptr()->pattern_);
   }
 
   intptr_t type_;  // Uninitialized, simple or complex.
   intptr_t flags_;  // Represents global/local, case insensitive, multiline.
 
   // Variable length data follows here.
   uint8_t data_[0];
 };
 
-
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_