lldb/source/Target/ThreadPlanStepOverBreakpoint.cpp

   1 //===-- ThreadPlanStepOverBreakpoint.cpp ----------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Target/ThreadPlanStepOverBreakpoint.h"
  10
  11 #include "lldb/Target/Process.h"
  12 #include "lldb/Target/RegisterContext.h"
  13 #include "lldb/Utility/LLDBLog.h"
  14 #include "lldb/Utility/Log.h"
  15 #include "lldb/Utility/Stream.h"
  16
  17 using namespace lldb;
  18 using namespace lldb_private;
  19
  20 // ThreadPlanStepOverBreakpoint: Single steps over a breakpoint bp_site_sp at
  21 // the pc.
  22
  23 ThreadPlanStepOverBreakpoint::ThreadPlanStepOverBreakpoint(Thread &thread)
  24     : ThreadPlan(
  25           ThreadPlan::eKindStepOverBreakpoint, "Step over breakpoint trap",
  26           thread, eVoteNo,
  27           eVoteNoOpinion), // We need to report the run since this happens
  28                            // first in the thread plan stack when stepping over
  29                            // a breakpoint
  30       m_breakpoint_addr(LLDB_INVALID_ADDRESS),
  31       m_auto_continue(false), m_reenabled_breakpoint_site(false)
  32
  33 {
  34   m_breakpoint_addr = thread.GetRegisterContext()->GetPC();
  35   m_breakpoint_site_id =
  36       thread.GetProcess()->GetBreakpointSiteList().FindIDByAddress(
  37           m_breakpoint_addr);
  38 }
  39
  40 ThreadPlanStepOverBreakpoint::~ThreadPlanStepOverBreakpoint() = default;
  41
  42 void ThreadPlanStepOverBreakpoint::GetDescription(
  43     Stream *s, lldb::DescriptionLevel level) {
  44   s->Printf("Single stepping past breakpoint site %" PRIu64 " at 0x%" PRIx64,
  45             m_breakpoint_site_id, (uint64_t)m_breakpoint_addr);
  46 }
  47
  48 bool ThreadPlanStepOverBreakpoint::ValidatePlan(Stream *error) { return true; }
  49
  50 bool ThreadPlanStepOverBreakpoint::DoPlanExplainsStop(Event *event_ptr) {
  51   StopInfoSP stop_info_sp = GetPrivateStopInfo();
  52   if (stop_info_sp) {
  53     StopReason reason = stop_info_sp->GetStopReason();
  54
  55     Log *log = GetLog(LLDBLog::Step);
  56     LLDB_LOG(log, "Step over breakpoint stopped for reason: {0}.",
  57              Thread::StopReasonAsString(reason));
  58
  59     switch (reason) {
  60       case eStopReasonTrace:
  61       case eStopReasonNone:
  62         return true;
  63       case eStopReasonBreakpoint:
  64       {
  65         // It's a little surprising that we stop here for a breakpoint hit.
  66         // However, when you single step ONTO a breakpoint we still want to call
  67         // that a breakpoint hit, and trigger the actions, etc.  Otherwise you
  68         // would see the PC at the breakpoint without having triggered the
  69         // actions, then you'd continue, the PC wouldn't change, and you'd see
  70         // the breakpoint hit, which would be odd. So the lower levels fake
  71         // "step onto breakpoint address" and return that as a breakpoint hit.
  72         // So our trace step COULD appear as a breakpoint hit if the next
  73         // instruction also contained a breakpoint.  We don't want to handle
  74         // that, since we really don't know what to do with breakpoint hits.
  75         // But make sure we don't set ourselves to auto-continue or we'll wrench
  76         // control away from the plans that can deal with this.
  77         // Be careful, however, as we may have "seen a breakpoint under the PC
  78         // because we stopped without changing the PC, in which case we do want
  79         // to re-claim this stop so we'll try again.
  80         lldb::addr_t pc_addr = GetThread().GetRegisterContext()->GetPC();
  81
  82         if (pc_addr == m_breakpoint_addr) {
  83           LLDB_LOGF(log,
  84                     "Got breakpoint stop reason but pc: 0x%" PRIx64
  85                     "hasn't changed.",
  86                     pc_addr);
  87           return true;
  88         }
  89
  90         SetAutoContinue(false);
  91         return false;
  92       }
  93       default:
  94         return false;
  95     }
  96   }
  97   return false;
  98 }
  99
 100 bool ThreadPlanStepOverBreakpoint::ShouldStop(Event *event_ptr) {
 101   return !ShouldAutoContinue(event_ptr);
 102 }
 103
 104 bool ThreadPlanStepOverBreakpoint::StopOthers() { return true; }
 105
 106 StateType ThreadPlanStepOverBreakpoint::GetPlanRunState() {
 107   return eStateStepping;
 108 }
 109
 110 bool ThreadPlanStepOverBreakpoint::DoWillResume(StateType resume_state,
 111                                                 bool current_plan) {
 112   if (current_plan) {
 113     BreakpointSiteSP bp_site_sp(
 114         m_process.GetBreakpointSiteList().FindByAddress(m_breakpoint_addr));
 115     if (bp_site_sp && bp_site_sp->IsEnabled()) {
 116       m_process.DisableBreakpointSite(bp_site_sp.get());
 117       m_reenabled_breakpoint_site = false;
 118     }
 119   }
 120   return true;
 121 }
 122
 123 bool ThreadPlanStepOverBreakpoint::WillStop() {
 124   ReenableBreakpointSite();
 125   return true;
 126 }
 127
 128 void ThreadPlanStepOverBreakpoint::DidPop() { ReenableBreakpointSite(); }
 129
 130 bool ThreadPlanStepOverBreakpoint::MischiefManaged() {
 131   lldb::addr_t pc_addr = GetThread().GetRegisterContext()->GetPC();
 132
 133   if (pc_addr == m_breakpoint_addr) {
 134     // If we are still at the PC of our breakpoint, then for some reason we
 135     // didn't get a chance to run.
 136     return false;
 137   } else {
 138     Log *log = GetLog(LLDBLog::Step);
 139     LLDB_LOGF(log, "Completed step over breakpoint plan.");
 140     // Otherwise, re-enable the breakpoint we were stepping over, and we're
 141     // done.
 142     ReenableBreakpointSite();
 143     ThreadPlan::MischiefManaged();
 144     return true;
 145   }
 146 }
 147
 148 void ThreadPlanStepOverBreakpoint::ReenableBreakpointSite() {
 149   if (!m_reenabled_breakpoint_site) {
 150     m_reenabled_breakpoint_site = true;
 151     BreakpointSiteSP bp_site_sp(
 152         m_process.GetBreakpointSiteList().FindByAddress(m_breakpoint_addr));
 153     if (bp_site_sp) {
 154       m_process.EnableBreakpointSite(bp_site_sp.get());
 155     }
 156   }
 157 }
 158 void ThreadPlanStepOverBreakpoint::ThreadDestroyed() {
 159   ReenableBreakpointSite();
 160 }
 161
 162 void ThreadPlanStepOverBreakpoint::SetAutoContinue(bool do_it) {
 163   m_auto_continue = do_it;
 164 }
 165
 166 bool ThreadPlanStepOverBreakpoint::ShouldAutoContinue(Event *event_ptr) {
 167   return m_auto_continue;
 168 }
 169
 170 bool ThreadPlanStepOverBreakpoint::IsPlanStale() {
 171   return GetThread().GetRegisterContext()->GetPC() != m_breakpoint_addr;
 172 }