- Wire the stack frame iterator to use stack maps for traversing objects if there are stack maps in…

vm/raw_object.cc

Index: vm/raw_object.cc
===================================================================
--- vm/raw_object.cc	(revision 5921)
+++ vm/raw_object.cc	(working copy)
@@ -228,6 +228,19 @@
 }
 
 
+bool RawObject::FindObject(FindObjectVisitor* visitor) {
+  ASSERT(visitor != NULL);
+  return visitor->FindObject(const_cast<RawObject*>(this));
+}
+
+
+bool RawObject::IsRawInstruction(RawObject* raw_obj) {
+  RawClass* raw_class = raw_obj->ptr()->class_;
+  ObjectKind instance_kind = raw_class->ptr()->instance_kind_;

[Ivan Posva, 2012/04/03 23:28:50]

This code could be inlined into the ContainsPC method.

[siva, 2012/04/07 01:22:55]

Done.

+  return (instance_kind == kInstructions);
+}
+
+
 intptr_t RawClass::VisitClassPointers(RawClass* raw_obj,
                                       ObjectPointerVisitor* visitor) {
   visitor->VisitPointers(raw_obj->from(), raw_obj->to());
@@ -361,6 +374,35 @@
 }
 
 
+RawStackmap* RawCode::GetStackmap(uword pc) const {

[Ivan Posva, 2012/04/03 23:28:50]

Move this code into the Code object?

[siva, 2012/04/07 01:22:55]

Done.

Used special stack handles in the DartFrame code to be able
to access this code using the handle. These stack handles
are not visited.

On 2012/04/03 23:28:50, Ivan Posva wrote:

+  RawArray* stackmaps = ptr()->stackmaps_;
+  if (stackmaps == Array::null()) {
+    // No stack maps are present in the code object which means this
+    // frame relies on tagged pointers.
+    return Stackmap::null();
+  }
+  // A stack map is present in the code object, use the stack map to visit
+  // frame slots which are marked as having objects.
+  RawStackmap* previous_map = Stackmap::null();
+  RawStackmap* map = Stackmap::null();
+  for (intptr_t i = 0; i < stackmaps->Length(); i++) {
+    map = reinterpret_cast<RawStackmap*>(stackmaps->DataAt(i));
+    ASSERT(map != Stackmap::null());
+    if (map->PC() == pc) {
+      break;  // We found a stack map for this frame.
+    }
+    if (map->PC() > pc) {
+      // We have not found a stackmap corresponding to the PC of this frame,
+      // we will use the closest previous stack map.
+      map = previous_map;
+      break;
+    }
+    previous_map = map;
+  }
+  return map;
+}
+
+
 intptr_t RawInstructions::VisitInstructionsPointers(
     RawInstructions* raw_obj, ObjectPointerVisitor* visitor) {
   RawInstructions* obj = raw_obj->ptr();
@@ -369,6 +411,21 @@
 }
 
 
+bool RawInstructions::ContainsPC(RawObject* raw_obj, uword pc) {
+  if (IsRawInstruction(raw_obj)) {
+    RawInstructions* raw_instr = reinterpret_cast<RawInstructions*>(raw_obj);
+    uword start_pc =
+        reinterpret_cast<uword>(raw_instr->ptr()) + Instructions::HeaderSize();
+    uword end_pc = start_pc + raw_instr->ptr()->size_;
+    ASSERT(end_pc > start_pc);
+    if ((pc >= start_pc) && (pc < end_pc)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+
 intptr_t RawPcDescriptors::VisitPcDescriptorsPointers(
     RawPcDescriptors* raw_obj, ObjectPointerVisitor* visitor) {
   RawPcDescriptors* obj = raw_obj->ptr();
@@ -387,6 +444,15 @@
 }
 
 
+bool RawStackmap::IsObject(intptr_t bit_offset) const {
+  const int byte_offset = bit_offset >> kBitsPerByteLog2;
+  const int bit_remainder = bit_offset & (kBitsPerByte - 1);
+  const uint8_t byte_mask = 1U << bit_remainder;
+  const uint8_t byte = ptr()->data_[byte_offset];
+  return (byte & byte_mask);
+}
+
+
 intptr_t RawLocalVarDescriptors::VisitLocalVarDescriptorsPointers(
     RawLocalVarDescriptors* raw_obj, ObjectPointerVisitor* visitor) {
   RawLocalVarDescriptors* obj = raw_obj->ptr();
@@ -609,6 +675,11 @@
 }
 
 
+intptr_t RawArray::Length() const {

[Ivan Posva, 2012/04/03 23:28:50]

inline into uses

[siva, 2012/04/07 01:22:55]

Not needed any more as the GetStackmap code was moved to a handle based one.

On 2012/04/03 23:28:50, Ivan Posva wrote:

+  return Smi::Value(ptr()->length_);
+}
+
+
 intptr_t RawImmutableArray::VisitImmutableArrayPointers(
     RawImmutableArray* raw_obj, ObjectPointerVisitor* visitor) {
   return RawArray::VisitArrayPointers(raw_obj, visitor);