1 //===-- ThreadPlanStepUntil.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/ThreadPlanStepUntil.h" 10 11 #include "lldb/Breakpoint/Breakpoint.h" 12 #include "lldb/Symbol/SymbolContextScope.h" 13 #include "lldb/Target/Process.h" 14 #include "lldb/Target/RegisterContext.h" 15 #include "lldb/Target/StopInfo.h" 16 #include "lldb/Target/Target.h" 17 #include "lldb/Utility/LLDBLog.h" 18 #include "lldb/Utility/Log.h" 19 20 using namespace lldb; 21 using namespace lldb_private; 22 23 // ThreadPlanStepUntil: Run until we reach a given line number or step out of 24 // the current frame 25 26 ThreadPlanStepUntil::ThreadPlanStepUntil(Thread &thread, 27 lldb::addr_t *address_list, 28 size_t num_addresses, bool stop_others, 29 uint32_t frame_idx) 30 : ThreadPlan(ThreadPlan::eKindStepUntil, "Step until", thread, 31 eVoteNoOpinion, eVoteNoOpinion), 32 m_step_from_insn(LLDB_INVALID_ADDRESS), 33 m_return_bp_id(LLDB_INVALID_BREAK_ID), 34 m_return_addr(LLDB_INVALID_ADDRESS), m_stepped_out(false), 35 m_should_stop(false), m_ran_analyze(false), m_explains_stop(false), 36 m_until_points(), m_stop_others(stop_others) { 37 // Stash away our "until" addresses: 38 TargetSP target_sp(thread.CalculateTarget()); 39 40 StackFrameSP frame_sp(thread.GetStackFrameAtIndex(frame_idx)); 41 if (frame_sp) { 42 m_step_from_insn = frame_sp->GetStackID().GetPC(); 43 44 // Find the return address and set a breakpoint there: 45 // FIXME - can we do this more securely if we know first_insn? 46 47 StackFrameSP return_frame_sp(thread.GetStackFrameAtIndex(frame_idx + 1)); 48 if (return_frame_sp) { 49 // TODO: add inline functionality 50 m_return_addr = return_frame_sp->GetStackID().GetPC(); 51 Breakpoint *return_bp = 52 target_sp->CreateBreakpoint(m_return_addr, true, false).get(); 53 54 if (return_bp != nullptr) { 55 if (return_bp->IsHardware() && !return_bp->HasResolvedLocations()) 56 m_could_not_resolve_hw_bp = true; 57 return_bp->SetThreadID(m_tid); 58 m_return_bp_id = return_bp->GetID(); 59 return_bp->SetBreakpointKind("until-return-backstop"); 60 } 61 } 62 63 m_stack_id = frame_sp->GetStackID(); 64 65 // Now set breakpoints on all our return addresses: 66 for (size_t i = 0; i < num_addresses; i++) { 67 Breakpoint *until_bp = 68 target_sp->CreateBreakpoint(address_list[i], true, false).get(); 69 if (until_bp != nullptr) { 70 until_bp->SetThreadID(m_tid); 71 m_until_points[address_list[i]] = until_bp->GetID(); 72 until_bp->SetBreakpointKind("until-target"); 73 } else { 74 m_until_points[address_list[i]] = LLDB_INVALID_BREAK_ID; 75 } 76 } 77 } 78 } 79 80 ThreadPlanStepUntil::~ThreadPlanStepUntil() { Clear(); } 81 82 void ThreadPlanStepUntil::Clear() { 83 Target &target = GetTarget(); 84 if (m_return_bp_id != LLDB_INVALID_BREAK_ID) { 85 target.RemoveBreakpointByID(m_return_bp_id); 86 m_return_bp_id = LLDB_INVALID_BREAK_ID; 87 } 88 89 until_collection::iterator pos, end = m_until_points.end(); 90 for (pos = m_until_points.begin(); pos != end; pos++) { 91 target.RemoveBreakpointByID((*pos).second); 92 } 93 m_until_points.clear(); 94 m_could_not_resolve_hw_bp = false; 95 } 96 97 void ThreadPlanStepUntil::GetDescription(Stream *s, 98 lldb::DescriptionLevel level) { 99 if (level == lldb::eDescriptionLevelBrief) { 100 s->Printf("step until"); 101 if (m_stepped_out) 102 s->Printf(" - stepped out"); 103 } else { 104 if (m_until_points.size() == 1) 105 s->Printf("Stepping from address 0x%" PRIx64 " until we reach 0x%" PRIx64 106 " using breakpoint %d", 107 (uint64_t)m_step_from_insn, 108 (uint64_t)(*m_until_points.begin()).first, 109 (*m_until_points.begin()).second); 110 else { 111 until_collection::iterator pos, end = m_until_points.end(); 112 s->Printf("Stepping from address 0x%" PRIx64 " until we reach one of:", 113 (uint64_t)m_step_from_insn); 114 for (pos = m_until_points.begin(); pos != end; pos++) { 115 s->Printf("\n\t0x%" PRIx64 " (bp: %d)", (uint64_t)(*pos).first, 116 (*pos).second); 117 } 118 } 119 s->Printf(" stepped out address is 0x%" PRIx64 ".", 120 (uint64_t)m_return_addr); 121 } 122 } 123 124 bool ThreadPlanStepUntil::ValidatePlan(Stream *error) { 125 if (m_could_not_resolve_hw_bp) { 126 if (error) 127 error->PutCString( 128 "Could not create hardware breakpoint for thread plan."); 129 return false; 130 } else if (m_return_bp_id == LLDB_INVALID_BREAK_ID) { 131 if (error) 132 error->PutCString("Could not create return breakpoint."); 133 return false; 134 } else { 135 until_collection::iterator pos, end = m_until_points.end(); 136 for (pos = m_until_points.begin(); pos != end; pos++) { 137 if (!LLDB_BREAK_ID_IS_VALID((*pos).second)) 138 return false; 139 } 140 return true; 141 } 142 } 143 144 void ThreadPlanStepUntil::AnalyzeStop() { 145 if (m_ran_analyze) 146 return; 147 148 StopInfoSP stop_info_sp = GetPrivateStopInfo(); 149 m_should_stop = true; 150 m_explains_stop = false; 151 152 if (stop_info_sp) { 153 StopReason reason = stop_info_sp->GetStopReason(); 154 155 if (reason == eStopReasonBreakpoint) { 156 // If this is OUR breakpoint, we're fine, otherwise we don't know why 157 // this happened... 158 BreakpointSiteSP this_site = 159 m_process.GetBreakpointSiteList().FindByID(stop_info_sp->GetValue()); 160 if (!this_site) { 161 m_explains_stop = false; 162 return; 163 } 164 165 if (this_site->IsBreakpointAtThisSite(m_return_bp_id)) { 166 // If we are at our "step out" breakpoint, and the stack depth has 167 // shrunk, then this is indeed our stop. If the stack depth has grown, 168 // then we've hit our step out breakpoint recursively. If we are the 169 // only breakpoint at that location, then we do explain the stop, and 170 // we'll just continue. If there was another breakpoint here, then we 171 // don't explain the stop, but we won't mark ourselves Completed, 172 // because maybe that breakpoint will continue, and then we'll finish 173 // the "until". 174 bool done; 175 StackID cur_frame_zero_id; 176 177 done = (m_stack_id < cur_frame_zero_id); 178 179 if (done) { 180 m_stepped_out = true; 181 SetPlanComplete(); 182 } else 183 m_should_stop = false; 184 185 if (this_site->GetNumberOfConstituents() == 1) 186 m_explains_stop = true; 187 else 188 m_explains_stop = false; 189 return; 190 } else { 191 // Check if we've hit one of our "until" breakpoints. 192 until_collection::iterator pos, end = m_until_points.end(); 193 for (pos = m_until_points.begin(); pos != end; pos++) { 194 if (this_site->IsBreakpointAtThisSite((*pos).second)) { 195 // If we're at the right stack depth, then we're done. 196 Thread &thread = GetThread(); 197 bool done; 198 StackID frame_zero_id = 199 thread.GetStackFrameAtIndex(0)->GetStackID(); 200 201 if (frame_zero_id == m_stack_id) 202 done = true; 203 else if (frame_zero_id < m_stack_id) 204 done = false; 205 else { 206 StackFrameSP older_frame_sp = thread.GetStackFrameAtIndex(1); 207 208 // But if we can't even unwind one frame we should just get out 209 // of here & stop... 210 if (older_frame_sp) { 211 const SymbolContext &older_context = 212 older_frame_sp->GetSymbolContext(eSymbolContextEverything); 213 SymbolContext stack_context; 214 m_stack_id.GetSymbolContextScope()->CalculateSymbolContext( 215 &stack_context); 216 217 done = (older_context == stack_context); 218 } else 219 done = false; 220 } 221 222 if (done) 223 SetPlanComplete(); 224 else 225 m_should_stop = false; 226 227 // Otherwise we've hit this breakpoint recursively. If we're the 228 // only breakpoint here, then we do explain the stop, and we'll 229 // continue. If not then we should let higher plans handle this 230 // stop. 231 if (this_site->GetNumberOfConstituents() == 1) 232 m_explains_stop = true; 233 else { 234 m_should_stop = true; 235 m_explains_stop = false; 236 } 237 return; 238 } 239 } 240 } 241 // If we get here we haven't hit any of our breakpoints, so let the 242 // higher plans take care of the stop. 243 m_explains_stop = false; 244 return; 245 } else if (IsUsuallyUnexplainedStopReason(reason)) { 246 m_explains_stop = false; 247 } else { 248 m_explains_stop = true; 249 } 250 } 251 } 252 253 bool ThreadPlanStepUntil::DoPlanExplainsStop(Event *event_ptr) { 254 // We don't explain signals or breakpoints (breakpoints that handle stepping 255 // in or out will be handled by a child plan. 256 AnalyzeStop(); 257 return m_explains_stop; 258 } 259 260 bool ThreadPlanStepUntil::ShouldStop(Event *event_ptr) { 261 // If we've told our self in ExplainsStop that we plan to continue, then do 262 // so here. Otherwise, as long as this thread has stopped for a reason, we 263 // will stop. 264 265 StopInfoSP stop_info_sp = GetPrivateStopInfo(); 266 if (!stop_info_sp || stop_info_sp->GetStopReason() == eStopReasonNone) 267 return false; 268 269 AnalyzeStop(); 270 return m_should_stop; 271 } 272 273 bool ThreadPlanStepUntil::StopOthers() { return m_stop_others; } 274 275 StateType ThreadPlanStepUntil::GetPlanRunState() { return eStateRunning; } 276 277 bool ThreadPlanStepUntil::DoWillResume(StateType resume_state, 278 bool current_plan) { 279 if (current_plan) { 280 Target &target = GetTarget(); 281 Breakpoint *return_bp = target.GetBreakpointByID(m_return_bp_id).get(); 282 if (return_bp != nullptr) 283 return_bp->SetEnabled(true); 284 285 until_collection::iterator pos, end = m_until_points.end(); 286 for (pos = m_until_points.begin(); pos != end; pos++) { 287 Breakpoint *until_bp = target.GetBreakpointByID((*pos).second).get(); 288 if (until_bp != nullptr) 289 until_bp->SetEnabled(true); 290 } 291 } 292 293 m_should_stop = true; 294 m_ran_analyze = false; 295 m_explains_stop = false; 296 return true; 297 } 298 299 bool ThreadPlanStepUntil::WillStop() { 300 Target &target = GetTarget(); 301 Breakpoint *return_bp = target.GetBreakpointByID(m_return_bp_id).get(); 302 if (return_bp != nullptr) 303 return_bp->SetEnabled(false); 304 305 until_collection::iterator pos, end = m_until_points.end(); 306 for (pos = m_until_points.begin(); pos != end; pos++) { 307 Breakpoint *until_bp = target.GetBreakpointByID((*pos).second).get(); 308 if (until_bp != nullptr) 309 until_bp->SetEnabled(false); 310 } 311 return true; 312 } 313 314 bool ThreadPlanStepUntil::MischiefManaged() { 315 // I'm letting "PlanExplainsStop" do all the work, and just reporting that 316 // here. 317 bool done = false; 318 if (IsPlanComplete()) { 319 Log *log = GetLog(LLDBLog::Step); 320 LLDB_LOGF(log, "Completed step until plan."); 321 322 Clear(); 323 done = true; 324 } 325 if (done) 326 ThreadPlan::MischiefManaged(); 327 328 return done; 329 } 330