[Lldb-commits] [lldb] r255417 - When supplying memory to expedite the unwinds in the T packet,

Jason Molenda via lldb-commits lldb-commits at lists.llvm.org
Fri Dec 11 17:32:09 PST 2015

Author: jmolenda
Date: Fri Dec 11 19:32:09 2015
New Revision: 255417

URL: http://llvm.org/viewvc/llvm-project?rev=255417&view=rev
When supplying memory to expedite the unwinds in the T packet,
include two stack frames worth of unwind information instead of
just one -- the unwinder is trying to fetch two stack frames in
more instances now and we're sending extra memory reads resulting
in a performance degredation while stepping.


Modified: lldb/trunk/tools/debugserver/source/RNBRemote.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/tools/debugserver/source/RNBRemote.cpp?rev=255417&r1=255416&r2=255417&view=diff
--- lldb/trunk/tools/debugserver/source/RNBRemote.cpp (original)
+++ lldb/trunk/tools/debugserver/source/RNBRemote.cpp Fri Dec 11 19:32:09 2015
@@ -2812,7 +2812,7 @@ RNBRemote::SendStopReplyPacketForThread
         // Add expedited stack memory so stack backtracing doesn't need to read anything from the
         // frame pointer chain.
         StackMemoryMap stack_mmap;
-        ReadStackMemory (pid, tid, stack_mmap, 1);
+        ReadStackMemory (pid, tid, stack_mmap, 2);
         if (!stack_mmap.empty())
             for (const auto &stack_memory : stack_mmap)

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