Fix stub frame walking: when materializing the frame content during deoptimization, the stack is no…

runtime/vm/stack_frame.cc

 // 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.
 
 #include "vm/stack_frame.h"
 
 #include "platform/memory_sanitizer.h"
 #include "vm/assembler.h"
 #include "vm/deopt_instructions.h"
 #include "vm/isolate.h"
@@ skipping 10 matching lines @@
 
 
 bool StackFrame::IsStubFrame() const {
   ASSERT(!(IsEntryFrame() || IsExitFrame()));
 #if !defined(TARGET_OS_WINDOWS)
   // On Windows, the profiler calls this from a separate thread where
   // Thread::Current() is NULL, so we cannot create a NoSafepointScope.
   NoSafepointScope no_safepoint;
 #endif
   RawCode* code = GetCodeObject();
-  intptr_t cid = code->ptr()->owner_->GetClassId();
+  if (code == Code::null()) {
+    // Frame not yet set up properly (e.g,deoptimization).
+    // This is slow, but rare.
+    const Code& code = Code::Handle(Code::LookupCode(pc()));
+    return code.IsStubCode();

[rmacnak, 2016/03/23 19:44:19]

assert code not null

[srdjan, 2016/03/23 19:48:22]

Done.

+  }
+  const intptr_t cid = code->ptr()->owner_->GetClassId();
   ASSERT(cid == kNullCid || cid == kClassCid || cid == kFunctionCid);
   return cid == kNullCid || cid == kClassCid;
 }
 
 
 const char* StackFrame::ToCString() const {
   ASSERT(thread_ == Thread::Current());
   Zone* zone = Thread::Current()->zone();
   if (IsDartFrame()) {
     const Code& code = Code::Handle(LookupDartCode());
@@ skipping 448 matching lines @@
     if (deopt_instr->kind() == DeoptInstr::kCallerFp) {
       return (index - num_materializations_);
     }
   }
   UNREACHABLE();
   return 0;
 }
 
 
 }  // namespace dart