labath created this revision. labath added a reviewer: clayborg. labath added a subscriber: lldb-commits.
This resolves a similar problem as D16720 (which handled the case when we single-step onto a breakpoint), but this one deals with involutary stops: when we stop a thread (e.g. because another thread has hit a breakpont and we are doing a full stop), we can end up stopping it right before it executes a breakpoint instruction. In this case, the stop reason will be empty, but we will still step over the breakpoint when do the next resume, thereby missing a breakpoint hit. I have observed this happening in TestConcurrentEvents, but I have no idea how to reproduce this behavior more reliably. http://reviews.llvm.org/D18692 Files: source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp Index: source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp =================================================================== --- source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp +++ source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp @@ -2089,6 +2089,23 @@ handled = true; } } + else + { + addr_t pc = thread_sp->GetRegisterContext()->GetPC(); + lldb::BreakpointSiteSP bp_site_sp = + thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(pc); + + // If the current pc is a breakpoint site then the StopInfo should be set to Breakpoint + // even though the remote stub did not set it as such. This can happen when + // the thread is involuntarily interrupted (e.g. due to stops on other + // threads) just as it is about to execute the breakpoint instruction. + if (bp_site_sp && bp_site_sp->ValidForThisThread(thread_sp.get())) + { + thread_sp->SetStopInfo( + StopInfo::CreateStopReasonWithBreakpointSiteID(*thread_sp, bp_site_sp->GetID())); + handled = true; + } + } if (!handled && signo && did_exec == false) {
Index: source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp =================================================================== --- source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp +++ source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp @@ -2089,6 +2089,23 @@ handled = true; } } + else + { + addr_t pc = thread_sp->GetRegisterContext()->GetPC(); + lldb::BreakpointSiteSP bp_site_sp = + thread_sp->GetProcess()->GetBreakpointSiteList().FindByAddress(pc); + + // If the current pc is a breakpoint site then the StopInfo should be set to Breakpoint + // even though the remote stub did not set it as such. This can happen when + // the thread is involuntarily interrupted (e.g. due to stops on other + // threads) just as it is about to execute the breakpoint instruction. + if (bp_site_sp && bp_site_sp->ValidForThisThread(thread_sp.get())) + { + thread_sp->SetStopInfo( + StopInfo::CreateStopReasonWithBreakpointSiteID(*thread_sp, bp_site_sp->GetID())); + handled = true; + } + } if (!handled && signo && did_exec == false) {
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