1 //===-- ThreadPlanStepThrough.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/ThreadPlanStepThrough.h" 10 #include "lldb/Breakpoint/Breakpoint.h" 11 #include "lldb/Target/DynamicLoader.h" 12 #include "lldb/Target/LanguageRuntime.h" 13 #include "lldb/Target/Process.h" 14 #include "lldb/Target/RegisterContext.h" 15 #include "lldb/Target/Target.h" 16 #include "lldb/Utility/Log.h" 17 #include "lldb/Utility/Stream.h" 18 19 using namespace lldb; 20 using namespace lldb_private; 21 22 // ThreadPlanStepThrough: If the current instruction is a trampoline, step 23 // through it If it is the beginning of the prologue of a function, step 24 // through that as well. 25 26 ThreadPlanStepThrough::ThreadPlanStepThrough(Thread &thread, 27 StackID &m_stack_id, 28 bool stop_others) 29 : ThreadPlan(ThreadPlan::eKindStepThrough, 30 "Step through trampolines and prologues", thread, 31 eVoteNoOpinion, eVoteNoOpinion), 32 m_start_address(0), m_backstop_bkpt_id(LLDB_INVALID_BREAK_ID), 33 m_backstop_addr(LLDB_INVALID_ADDRESS), m_return_stack_id(m_stack_id), 34 m_stop_others(stop_others) { 35 LookForPlanToStepThroughFromCurrentPC(); 36 37 // If we don't get a valid step through plan, don't bother to set up a 38 // backstop. 39 if (m_sub_plan_sp) { 40 m_start_address = GetThread().GetRegisterContext()->GetPC(0); 41 42 // We are going to return back to the concrete frame 1, we might pass by 43 // some inlined code that we're in the middle of by doing this, but it's 44 // easier than trying to figure out where the inlined code might return to. 45 46 StackFrameSP return_frame_sp = thread.GetFrameWithStackID(m_stack_id); 47 48 if (return_frame_sp) { 49 m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress( 50 thread.CalculateTarget().get()); 51 Breakpoint *return_bp = 52 m_process.GetTarget() 53 .CreateBreakpoint(m_backstop_addr, true, false) 54 .get(); 55 56 if (return_bp != nullptr) { 57 if (return_bp->IsHardware() && !return_bp->HasResolvedLocations()) 58 m_could_not_resolve_hw_bp = true; 59 return_bp->SetThreadID(m_tid); 60 m_backstop_bkpt_id = return_bp->GetID(); 61 return_bp->SetBreakpointKind("step-through-backstop"); 62 } 63 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 64 if (log) { 65 LLDB_LOGF(log, "Setting backstop breakpoint %d at address: 0x%" PRIx64, 66 m_backstop_bkpt_id, m_backstop_addr); 67 } 68 } 69 } 70 } 71 72 ThreadPlanStepThrough::~ThreadPlanStepThrough() { ClearBackstopBreakpoint(); } 73 74 void ThreadPlanStepThrough::DidPush() { 75 if (m_sub_plan_sp) 76 PushPlan(m_sub_plan_sp); 77 } 78 79 void ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC() { 80 Thread &thread = GetThread(); 81 DynamicLoader *loader = thread.GetProcess()->GetDynamicLoader(); 82 if (loader) 83 m_sub_plan_sp = loader->GetStepThroughTrampolinePlan(thread, m_stop_others); 84 85 // If the DynamicLoader was unable to provide us with a ThreadPlan, then we 86 // try the LanguageRuntimes. 87 if (!m_sub_plan_sp) { 88 for (LanguageRuntime *runtime : m_process.GetLanguageRuntimes()) { 89 m_sub_plan_sp = 90 runtime->GetStepThroughTrampolinePlan(thread, m_stop_others); 91 92 if (m_sub_plan_sp) 93 break; 94 } 95 } 96 97 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 98 if (log) { 99 lldb::addr_t current_address = GetThread().GetRegisterContext()->GetPC(0); 100 if (m_sub_plan_sp) { 101 StreamString s; 102 m_sub_plan_sp->GetDescription(&s, lldb::eDescriptionLevelFull); 103 LLDB_LOGF(log, "Found step through plan from 0x%" PRIx64 ": %s", 104 current_address, s.GetData()); 105 } else { 106 LLDB_LOGF(log, 107 "Couldn't find step through plan from address 0x%" PRIx64 ".", 108 current_address); 109 } 110 } 111 } 112 113 void ThreadPlanStepThrough::GetDescription(Stream *s, 114 lldb::DescriptionLevel level) { 115 if (level == lldb::eDescriptionLevelBrief) 116 s->Printf("Step through"); 117 else { 118 s->PutCString("Stepping through trampoline code from: "); 119 DumpAddress(s->AsRawOstream(), m_start_address, sizeof(addr_t)); 120 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) { 121 s->Printf(" with backstop breakpoint ID: %d at address: ", 122 m_backstop_bkpt_id); 123 DumpAddress(s->AsRawOstream(), m_backstop_addr, sizeof(addr_t)); 124 } else 125 s->PutCString(" unable to set a backstop breakpoint."); 126 } 127 } 128 129 bool ThreadPlanStepThrough::ValidatePlan(Stream *error) { 130 if (m_could_not_resolve_hw_bp) { 131 if (error) 132 error->PutCString( 133 "Could not create hardware breakpoint for thread plan."); 134 return false; 135 } 136 137 if (m_backstop_bkpt_id == LLDB_INVALID_BREAK_ID) { 138 if (error) 139 error->PutCString("Could not create backstop breakpoint."); 140 return false; 141 } 142 143 if (!m_sub_plan_sp.get()) { 144 if (error) 145 error->PutCString("Does not have a subplan."); 146 return false; 147 } 148 149 return true; 150 } 151 152 bool ThreadPlanStepThrough::DoPlanExplainsStop(Event *event_ptr) { 153 // If we have a sub-plan, it will have been asked first if we explain the 154 // stop, and we won't get asked. The only time we would be the one directly 155 // asked this question is if we hit our backstop breakpoint. 156 157 return HitOurBackstopBreakpoint(); 158 } 159 160 bool ThreadPlanStepThrough::ShouldStop(Event *event_ptr) { 161 // If we've already marked ourselves done, then we're done... 162 if (IsPlanComplete()) 163 return true; 164 165 // First, did we hit the backstop breakpoint? 166 if (HitOurBackstopBreakpoint()) { 167 SetPlanComplete(true); 168 return true; 169 } 170 171 // If we don't have a sub-plan, then we're also done (can't see how we would 172 // ever get here without a plan, but just in case. 173 174 if (!m_sub_plan_sp) { 175 SetPlanComplete(); 176 return true; 177 } 178 179 // If the current sub plan is not done, we don't want to stop. Actually, we 180 // probably won't ever get here in this state, since we generally won't get 181 // asked any questions if out current sub-plan is not done... 182 if (!m_sub_plan_sp->IsPlanComplete()) 183 return false; 184 185 // If our current sub plan failed, then let's just run to our backstop. If 186 // we can't do that then just stop. 187 if (!m_sub_plan_sp->PlanSucceeded()) { 188 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) { 189 m_sub_plan_sp.reset(); 190 return false; 191 } else { 192 SetPlanComplete(false); 193 return true; 194 } 195 } 196 197 // Next see if there is a specific step through plan at our current pc (these 198 // might chain, for instance stepping through a dylib trampoline to the objc 199 // dispatch function...) 200 LookForPlanToStepThroughFromCurrentPC(); 201 if (m_sub_plan_sp) { 202 PushPlan(m_sub_plan_sp); 203 return false; 204 } else { 205 SetPlanComplete(); 206 return true; 207 } 208 } 209 210 bool ThreadPlanStepThrough::StopOthers() { return m_stop_others; } 211 212 StateType ThreadPlanStepThrough::GetPlanRunState() { return eStateRunning; } 213 214 bool ThreadPlanStepThrough::DoWillResume(StateType resume_state, 215 bool current_plan) { 216 return true; 217 } 218 219 bool ThreadPlanStepThrough::WillStop() { return true; } 220 221 void ThreadPlanStepThrough::ClearBackstopBreakpoint() { 222 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) { 223 m_process.GetTarget().RemoveBreakpointByID(m_backstop_bkpt_id); 224 m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID; 225 m_could_not_resolve_hw_bp = false; 226 } 227 } 228 229 bool ThreadPlanStepThrough::MischiefManaged() { 230 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 231 232 if (!IsPlanComplete()) { 233 return false; 234 } else { 235 LLDB_LOGF(log, "Completed step through step plan."); 236 237 ClearBackstopBreakpoint(); 238 ThreadPlan::MischiefManaged(); 239 return true; 240 } 241 } 242 243 bool ThreadPlanStepThrough::HitOurBackstopBreakpoint() { 244 Thread &thread = GetThread(); 245 StopInfoSP stop_info_sp(thread.GetStopInfo()); 246 if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint) { 247 break_id_t stop_value = (break_id_t)stop_info_sp->GetValue(); 248 BreakpointSiteSP cur_site_sp = 249 m_process.GetBreakpointSiteList().FindByID(stop_value); 250 if (cur_site_sp && 251 cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id)) { 252 StackID cur_frame_zero_id = thread.GetStackFrameAtIndex(0)->GetStackID(); 253 254 if (cur_frame_zero_id == m_return_stack_id) { 255 Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP)); 256 if (log) 257 log->PutCString("ThreadPlanStepThrough hit backstop breakpoint."); 258 return true; 259 } 260 } 261 } 262 return false; 263 } 264