Link stack frames of JNI stubs to JNI callbacks.

base/debug/stack_trace.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/stack_trace.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <sstream>
@@ skipping 158 matching lines @@
       if (IsStackFrameValid(next2_fp, next_fp, stack_end)) {
         return fp;
       }
     }
   }
 #endif  // defined(OS_LINUX)
 
   return 0;
 }
 
+// Links stack frame |fp| to |parent_fp|, so that during stack unwinding

[Primiano Tucci (use gerrit), 2016/10/13 20:03:21]

I think you commented this already in the .h. Usually that is fine.

[Dmitry Skiba, 2016/10/17 22:09:11]

That was for ScopedStackFrameLinker thing, and I remember you asked earlier what
fp and parent_fp arguments are, so I decided to put comment here too.

+// TraceStackFramePointers() visits |parent_fp| after visiting |fp|.
+// Both frame pointers must come from __builtin_frame_address().
+// Returns previous stack frame |fp| was linked to.
+void* LinkStackFrames(void* fpp, void* parent_fp) {
+  uintptr_t fp = reinterpret_cast<uintptr_t>(fpp) - kStackFrameAdjustment;
+  void* prev_parent_fp = reinterpret_cast<void**>(fp)[0];
+  reinterpret_cast<void**>(fp)[0] = parent_fp;
+  return prev_parent_fp;
+}
+
 #endif  // HAVE_TRACE_STACK_FRAME_POINTERS
 
 }  // namespace
 
 StackTrace::StackTrace(const void* const* trace, size_t count) {
   count = std::min(count, arraysize(trace_));
   if (count)
     memcpy(trace_, trace, count * sizeof(trace_[0]));
   count_ = count;
 }
@@ skipping 49 matching lines @@
       continue;
     }
 
     // Failed to find next frame.
     break;
   }
 
   return depth;
 }
 
+ScopedStackFrameLinker::ScopedStackFrameLinker(void* fp, void* parent_fp)
+  : fp_(fp), original_parent_fp_(LinkStackFrames(fp, parent_fp)) {}
+
+ScopedStackFrameLinker::~ScopedStackFrameLinker() {
+  LinkStackFrames(fp_, original_parent_fp_);

[Primiano Tucci (use gerrit), 2016/10/13 20:03:21]

could you add a CHECK here that verifies that the content of the fp saved on the
stack still matches what you did set in the ctor, before resetting?
If something goes unexpectedly wrong at least we'd fail very fast showing where
the problem is.
I'd make this a CHECK and not a DCHECK beause almost nobody uses debug on
android builds.

[Dmitry Skiba, 2016/10/17 22:09:11]

Done.

+}
+
 #endif  // HAVE_TRACE_STACK_FRAME_POINTERS
 
 }  // namespace debug
 }  // namespace base