Removes open arrays (e.g. data[0]) from raw objects.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
===================================================================
--- runtime/vm/raw_object.h	(revision 37367)
+++ runtime/vm/raw_object.h	(working copy)
@@ -558,9 +558,13 @@
   RawSmi* length_;
 
   // Variable length data follows here.
-  RawAbstractType* types_[0];
+  RawAbstractType** types() {
+    const uword address_of_length = reinterpret_cast<uword>(&length_);
+    return reinterpret_cast<RawAbstractType**>(
+        address_of_length + sizeof(length_));
+  }
   RawObject** to(intptr_t length) {
-    return reinterpret_cast<RawObject**>(&ptr()->types_[length - 1]);
+    return reinterpret_cast<RawObject**>(&ptr()->types()[length - 1]);
   }
 
   friend class SnapshotReader;
@@ -853,10 +857,12 @@
   intptr_t patch_code_pc_offset_;
   intptr_t lazy_deopt_pc_offset_;
 
-  intptr_t dummy_alignment_;
-
   // Variable length data follows here.
-  int32_t data_[0];
+  int32_t* data() {
+    uword address_of_lazy = reinterpret_cast<uword>(&lazy_deopt_pc_offset_);

[Ivan Posva, 2014/06/16 23:02:13]

As discussed this pattern looks a bit fragile from the point of keeping size and
alignment in sync with expectations.

[zra, 2014/06/17 17:24:08]

Changed to:

const uword result = reinterpret_cast<uword>(this) + sizeof(*this);
ASSERT(Utils::IsAligned(result, sizeof(int32_t)));
return reinterpret_cast<int32_t*>(result);

With the appropriate types substituted for int32_t in other places.

+    return reinterpret_cast<int32_t*>(
+        address_of_lazy + sizeof(lazy_deopt_pc_offset_));
+  }
 
   friend class StackFrame;
   friend class MarkingVisitor;
@@ -878,7 +884,10 @@
   intptr_t size_;
 
   // Variable length data follows here.
-  uint8_t data_[0];
+  uint8_t* data() {
+    const uword address_of_size = reinterpret_cast<uword>(&size_);
+    return reinterpret_cast<uint8_t*>(address_of_size + sizeof(size_));
+  }
 
   // Private helper function used while visiting stack frames. The
   // code which iterates over dart frames is also called during GC and
@@ -899,7 +908,10 @@
   intptr_t length_;  // Number of descriptors.
 
   // Variable length data follows here.
-  intptr_t data_[0];
+  intptr_t* data() {
+    const uword address_of_length = reinterpret_cast<uword>(&length_);
+    return reinterpret_cast<intptr_t*>(address_of_length + sizeof(length_));
+  }
 
   friend class Object;
 };
@@ -923,7 +935,10 @@
   uword pc_;  // PC corresponding to this stack map representation.
 
   // Variable length data follows here (bitmap of the stack layout).
-  uint8_t data_[0];
+  uint8_t* data() {
+    const uword address_of_pc = reinterpret_cast<uword>(&pc_);
+    return reinterpret_cast<uint8_t*>(address_of_pc + sizeof(pc_));
+  }
 };
 
 
@@ -950,7 +965,11 @@
   intptr_t length_;  // Number of descriptors.
   RawArray* names_;  // Array of [length_] variable names.
 
-  VarInfo data_[0];   // Variable info with [length_] entries.
+  // Variable info with [length_] entries.
+  VarInfo* data() {
+    const uword address_of_names = reinterpret_cast<uword>(&names_);
+    return reinterpret_cast<VarInfo*>(address_of_names + sizeof(names_));
+  }
 };
 
 
@@ -964,6 +983,7 @@
     int8_t needs_stacktrace;   // True if a stacktrace is needed.
     int8_t has_catch_all;      // Catches all exceptions.
   };
+
  private:
   RAW_HEAP_OBJECT_IMPLEMENTATION(ExceptionHandlers);
 
@@ -975,7 +995,11 @@
   RawArray* handled_types_data_;
 
   // Exception handler info of length [length_].
-  HandlerInfo data_[0];
+  HandlerInfo* data() {
+    const uword address_of_htd = reinterpret_cast<uword>(&handled_types_data_);
+    return reinterpret_cast<HandlerInfo*>(
+        address_of_htd + sizeof(handled_types_data_));
+  }
 };
 
 
@@ -987,7 +1011,10 @@
   RawSmi* length_;  // Number of deoptimization commands
 
   // Variable length data follows here.
-  intptr_t data_[0];
+  intptr_t* data() {
+    const uword address_of_length = reinterpret_cast<uword>(&length_);
+    return reinterpret_cast<intptr_t*>(address_of_length + sizeof(length_));
+  }
 };
 
 
@@ -1001,9 +1028,13 @@
   RawContext* parent_;
 
   // Variable length data follows here.
-  RawInstance* data_[0];
+  RawInstance** data() {
+    const uword address_of_parent = reinterpret_cast<uword>(&parent_);
+    return reinterpret_cast<RawInstance**>(
+        address_of_parent + sizeof(parent_));
+  }
   RawObject** to(intptr_t num_vars) {
-    return reinterpret_cast<RawObject**>(&ptr()->data_[num_vars - 1]);
+    return reinterpret_cast<RawObject**>(&ptr()->data()[num_vars - 1]);
   }
 
   friend class SnapshotReader;
@@ -1031,11 +1062,17 @@
   intptr_t num_variables_;
 
   // Variable length data follows here.
-  RawObject** from() { return reinterpret_cast<RawObject**>(&ptr()->data_[0]); }
-  RawObject* data_[0];
+  RawObject** from() {
+    return reinterpret_cast<RawObject**>(&ptr()->data()[0]);
+  }
+  RawObject** data() {
+    const uword address_of_nv = reinterpret_cast<uword>(&num_variables_);
+    return reinterpret_cast<RawObject**>(
+        address_of_nv + sizeof(num_variables_));
+  }
   RawObject** to(intptr_t num_vars) {
-    intptr_t data_length = num_vars * (sizeof(VariableDesc)/kWordSize);
-    return reinterpret_cast<RawObject**>(&ptr()->data_[data_length - 1]);
+    const intptr_t data_length = num_vars * (sizeof(VariableDesc)/kWordSize);
+    return reinterpret_cast<RawObject**>(&ptr()->data()[data_length - 1]);
   }
 };
 
@@ -1304,7 +1341,11 @@
 
   // A sequence of Chunks (typedef in Bignum) representing bignum digits.
   // Bignum::Chunk chunks_[Utils::Abs(signed_length_)];
-  uint8_t data_[0];
+  uint8_t* data() {
+    const uword address_of_length = reinterpret_cast<uword>(&signed_length_);
+    return reinterpret_cast<uint8_t*>(
+        address_of_length + sizeof(signed_length_));
+  }
 
   friend class SnapshotReader;
 };
@@ -1335,7 +1376,10 @@
   RAW_HEAP_OBJECT_IMPLEMENTATION(OneByteString);
 
   // Variable length data follows here.
-  uint8_t data_[0];
+  uint8_t* data() {
+    const uword address_of_hash = reinterpret_cast<uword>(&hash_);
+    return reinterpret_cast<uint8_t*>(address_of_hash + sizeof(hash_));
+  }
 
   friend class ApiMessageReader;
   friend class SnapshotReader;
@@ -1346,7 +1390,10 @@
   RAW_HEAP_OBJECT_IMPLEMENTATION(TwoByteString);
 
   // Variable length data follows here.
-  uint16_t data_[0];
+  uint16_t* data() {
+    const uword address_of_hash = reinterpret_cast<uword>(&hash_);
+    return reinterpret_cast<uint16_t*>(address_of_hash + sizeof(hash_));
+  }
 
   friend class SnapshotReader;
 };
@@ -1410,7 +1457,7 @@
   // Variable length data follows here.
   RawObject** data() {
     uword address_of_length = reinterpret_cast<uword>(&length_);
-    return reinterpret_cast<RawObject**>(address_of_length + kWordSize);
+    return reinterpret_cast<RawObject**>(address_of_length + sizeof(length_));
   }
   RawObject** to(intptr_t length) {
     return reinterpret_cast<RawObject**>(&ptr()->data()[length - 1]);
@@ -1508,11 +1555,13 @@
  protected:
   RawObject** from() { return reinterpret_cast<RawObject**>(&ptr()->length_); }
   RawSmi* length_;
+  // Variable length data follows here.
+  uint8_t* data() {
+    uword address_of_length = reinterpret_cast<uword>(&length_);
+    return reinterpret_cast<uint8_t*>(address_of_length + sizeof(length_));
+  }
   RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->length_); }
 
-  // Variable length data follows here.
-  uint8_t data_[0];
-
   friend class Api;
   friend class Object;
   friend class Instance;
@@ -1602,7 +1651,10 @@
   intptr_t flags_;  // Represents global/local, case insensitive, multiline.
 
   // Variable length data follows here.
-  uint8_t data_[0];
+  uint8_t* data() {
+    const uword address_of_flags = reinterpret_cast<uword>(&flags_);
+    return reinterpret_cast<uint8_t*>(address_of_flags + sizeof(flags_));
+  }
 };