[Lldb-commits] [PATCH] D29669: Hardware breakpoints implementation for AArch64 targets

Muhammad Omair Javaid via Phabricator via lldb-commits lldb-commits at lists.llvm.org
Thu Feb 9 03:02:06 PST 2017

omjavaid added a comment.

In https://reviews.llvm.org/D29669#670896, @clayborg wrote:

> I would prefer to see NativeBreakpoint struct expanded to have more member variables instead of adding a new hardware breakpoint list. Then you just ask any breakpoint to enable/disable/remove itself and the structure contains all of the info we need. Keeping two lists means we have to check two lists. Let me know if any of my inline comments weren't clear?

So I thought about it but gave up on the idea for two reasons:

1. Hardware breakpoints implementation has more similarities with hardware watchpoints than software breakpoints and I plan to consolidate both functionalities onces hardware brekapoints start working.

2. Software breakpoint are implemented with process wide scope and hardware breakpoints are thread specific which means that we add existing hw breakpoint on all new threads. On resume we ll be traversing through a breakpoint list which predominantly has only software breakpoints in most cases a overhead will be added in case we  have 20 software breakpoint and just 1 hardware breakpoint installed by user.

Let me know what do you think about above two ppoints and I ll clear up all other comments in following revision.


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