Introduce concurrent on-stack replacement.

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 10307 matching lines @@
       // Don't clear AllocationSites
       Object* value = cell->value();
       if (value == NULL || !value->IsAllocationSite()) {
         cell->set_value(TypeFeedbackCells::RawUninitializedSentinel(heap));
       }
     }
   }
 }
 
 
+BailoutId Code::TranslatePcOffsetToAstId(uint32_t pc_offset) {

[titzer, 2013/09/04 09:23:23]

ASSERT(kind() == FUNCTION)

[Yang, 2013/09/04 12:55:12]

Done. The BackEdgeTableIterator asserts the same, but I guess it doesn't hurt.

+  DisallowHeapAllocation no_gc;
+  for (FullCodeGenerator::BackEdgeTableIterator it(this, &no_gc);
+       !it.Done();
+       it.Next()) {
+    if (it.pc_offset() == pc_offset) return it.ast_id();
+  }
+  return BailoutId::None();
+}
+
+
 bool Code::allowed_in_shared_map_code_cache() {
   return is_keyed_load_stub() || is_keyed_store_stub() ||
       (is_compare_ic_stub() &&
        ICCompareStub::CompareState(stub_info()) == CompareIC::KNOWN_OBJECT);
 }
 
 
 void Code::MakeCodeAgeSequenceYoung(byte* sequence) {
   PatchPlatformCodeAge(sequence, kNoAge, NO_MARKING_PARITY);
 }
@@ skipping 440 matching lines @@
         PrintF(out, " argc: %d", entry.argument_count());
       }
       PrintF(out, "\n");
     }
     PrintF(out, "\n");
   } else if (kind() == FUNCTION) {
     unsigned offset = back_edge_table_offset();
     // If there is no back edge table, the "table start" will be at or after
     // (due to alignment) the end of the instruction stream.
     if (static_cast<int>(offset) < instruction_size()) {
-      FullCodeGenerator::BackEdgeTableIterator back_edges(this);
+      DisallowHeapAllocation no_gc;
+      FullCodeGenerator::BackEdgeTableIterator back_edges(this, &no_gc);
 
       PrintF(out, "Back edges (size = %u)\n", back_edges.table_length());
       PrintF(out, "ast_id  pc_offset  loop_depth\n");
 
       for ( ; !back_edges.Done(); back_edges.Next()) {
         PrintF(out, "%6d  %9u  %10u\n", back_edges.ast_id().ToInt(),
                                         back_edges.pc_offset(),
                                         back_edges.loop_depth());
       }
 
@@ skipping 5169 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal