265 lines · cpp
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-exception6//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/LLDBLog.h"17#include "lldb/Utility/Log.h"18#include "lldb/Utility/Stream.h"19 20using namespace lldb;21using namespace lldb_private;22 23// ThreadPlanStepThrough: If the current instruction is a trampoline, step24// through it If it is the beginning of the prologue of a function, step25// through that as well.26 27ThreadPlanStepThrough::ThreadPlanStepThrough(Thread &thread,28 StackID &m_stack_id,29 bool stop_others)30 : ThreadPlan(ThreadPlan::eKindStepThrough,31 "Step through trampolines and prologues", thread,32 eVoteNoOpinion, eVoteNoOpinion),33 m_start_address(0), m_backstop_bkpt_id(LLDB_INVALID_BREAK_ID),34 m_backstop_addr(LLDB_INVALID_ADDRESS), m_return_stack_id(m_stack_id),35 m_stop_others(stop_others) {36 LookForPlanToStepThroughFromCurrentPC();37 38 // If we don't get a valid step through plan, don't bother to set up a39 // backstop.40 if (m_sub_plan_sp) {41 m_start_address = GetThread().GetRegisterContext()->GetPC(0);42 43 // We are going to return back to the concrete frame 1, we might pass by44 // some inlined code that we're in the middle of by doing this, but it's45 // easier than trying to figure out where the inlined code might return to.46 47 StackFrameSP return_frame_sp = thread.GetFrameWithStackID(m_stack_id);48 49 if (return_frame_sp) {50 m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(51 thread.CalculateTarget().get());52 Breakpoint *return_bp =53 m_process.GetTarget()54 .CreateBreakpoint(m_backstop_addr, true, false)55 .get();56 57 if (return_bp != nullptr) {58 if (return_bp->IsHardware() && !return_bp->HasResolvedLocations())59 m_could_not_resolve_hw_bp = true;60 return_bp->SetThreadID(m_tid);61 m_backstop_bkpt_id = return_bp->GetID();62 return_bp->SetBreakpointKind("step-through-backstop");63 }64 Log *log = GetLog(LLDBLog::Step);65 if (log) {66 LLDB_LOGF(log, "Setting backstop breakpoint %d at address: 0x%" PRIx64,67 m_backstop_bkpt_id, m_backstop_addr);68 }69 }70 }71}72 73ThreadPlanStepThrough::~ThreadPlanStepThrough() { ClearBackstopBreakpoint(); }74 75void ThreadPlanStepThrough::DidPush() {76 if (m_sub_plan_sp)77 PushPlan(m_sub_plan_sp);78}79 80void ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC() {81 Thread &thread = GetThread();82 DynamicLoader *loader = thread.GetProcess()->GetDynamicLoader();83 if (loader)84 m_sub_plan_sp = loader->GetStepThroughTrampolinePlan(thread, m_stop_others);85 86 // If the DynamicLoader was unable to provide us with a ThreadPlan, then we87 // try the LanguageRuntimes.88 if (!m_sub_plan_sp) {89 for (LanguageRuntime *runtime : m_process.GetLanguageRuntimes()) {90 m_sub_plan_sp =91 runtime->GetStepThroughTrampolinePlan(thread, m_stop_others);92 93 if (m_sub_plan_sp)94 break;95 }96 }97 98 Log *log = GetLog(LLDBLog::Step);99 if (log) {100 lldb::addr_t current_address = GetThread().GetRegisterContext()->GetPC(0);101 if (m_sub_plan_sp) {102 StreamString s;103 m_sub_plan_sp->GetDescription(&s, lldb::eDescriptionLevelFull);104 LLDB_LOGF(log, "Found step through plan from 0x%" PRIx64 ": %s",105 current_address, s.GetData());106 } else {107 LLDB_LOGF(log,108 "Couldn't find step through plan from address 0x%" PRIx64 ".",109 current_address);110 }111 }112}113 114void ThreadPlanStepThrough::GetDescription(Stream *s,115 lldb::DescriptionLevel level) {116 if (level == lldb::eDescriptionLevelBrief)117 s->Printf("Step through");118 else {119 s->PutCString("Stepping through trampoline code from: ");120 DumpAddress(s->AsRawOstream(), m_start_address, sizeof(addr_t));121 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {122 s->Printf(" with backstop breakpoint ID: %d at address: ",123 m_backstop_bkpt_id);124 DumpAddress(s->AsRawOstream(), m_backstop_addr, sizeof(addr_t));125 } else126 s->PutCString(" unable to set a backstop breakpoint.");127 }128}129 130bool ThreadPlanStepThrough::ValidatePlan(Stream *error) {131 if (m_could_not_resolve_hw_bp) {132 if (error)133 error->PutCString(134 "Could not create hardware breakpoint for thread plan.");135 return false;136 }137 138 if (m_backstop_bkpt_id == LLDB_INVALID_BREAK_ID) {139 if (error)140 error->PutCString("Could not create backstop breakpoint.");141 return false;142 }143 144 if (!m_sub_plan_sp.get()) {145 if (error)146 error->PutCString("Does not have a subplan.");147 return false;148 }149 150 return true;151}152 153bool ThreadPlanStepThrough::DoPlanExplainsStop(Event *event_ptr) {154 // If we have a sub-plan, it will have been asked first if we explain the155 // stop, and we won't get asked. The only time we would be the one directly156 // asked this question is if we hit our backstop breakpoint.157 158 return HitOurBackstopBreakpoint();159}160 161bool ThreadPlanStepThrough::ShouldStop(Event *event_ptr) {162 // If we've already marked ourselves done, then we're done...163 if (IsPlanComplete())164 return true;165 166 // First, did we hit the backstop breakpoint?167 if (HitOurBackstopBreakpoint()) {168 SetPlanComplete(true);169 return true;170 }171 172 // If we don't have a sub-plan, then we're also done (can't see how we would173 // ever get here without a plan, but just in case.174 175 if (!m_sub_plan_sp) {176 SetPlanComplete();177 return true;178 }179 180 // If the current sub plan is not done, we don't want to stop. Actually, we181 // probably won't ever get here in this state, since we generally won't get182 // asked any questions if out current sub-plan is not done...183 if (!m_sub_plan_sp->IsPlanComplete())184 return false;185 186 // If our current sub plan failed, then let's just run to our backstop. If187 // we can't do that then just stop.188 if (!m_sub_plan_sp->PlanSucceeded()) {189 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {190 m_sub_plan_sp.reset();191 return false;192 } else {193 SetPlanComplete(false);194 return true;195 }196 }197 198 // Next see if there is a specific step through plan at our current pc (these199 // might chain, for instance stepping through a dylib trampoline to the objc200 // dispatch function...)201 LookForPlanToStepThroughFromCurrentPC();202 if (m_sub_plan_sp) {203 PushPlan(m_sub_plan_sp);204 return false;205 } else {206 SetPlanComplete();207 return true;208 }209}210 211bool ThreadPlanStepThrough::StopOthers() { return m_stop_others; }212 213StateType ThreadPlanStepThrough::GetPlanRunState() { return eStateRunning; }214 215bool ThreadPlanStepThrough::DoWillResume(StateType resume_state,216 bool current_plan) {217 return true;218}219 220bool ThreadPlanStepThrough::WillStop() { return true; }221 222void ThreadPlanStepThrough::ClearBackstopBreakpoint() {223 if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {224 m_process.GetTarget().RemoveBreakpointByID(m_backstop_bkpt_id);225 m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;226 m_could_not_resolve_hw_bp = false;227 }228}229 230bool ThreadPlanStepThrough::MischiefManaged() {231 Log *log = GetLog(LLDBLog::Step);232 233 if (!IsPlanComplete()) {234 return false;235 } else {236 LLDB_LOGF(log, "Completed step through step plan.");237 238 ClearBackstopBreakpoint();239 ThreadPlan::MischiefManaged();240 return true;241 }242}243 244bool ThreadPlanStepThrough::HitOurBackstopBreakpoint() {245 Thread &thread = GetThread();246 StopInfoSP stop_info_sp(thread.GetStopInfo());247 if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint) {248 break_id_t stop_value = (break_id_t)stop_info_sp->GetValue();249 BreakpointSiteSP cur_site_sp =250 m_process.GetBreakpointSiteList().FindByID(stop_value);251 if (cur_site_sp &&252 cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id)) {253 StackID cur_frame_zero_id = thread.GetStackFrameAtIndex(0)->GetStackID();254 255 if (cur_frame_zero_id == m_return_stack_id) {256 Log *log = GetLog(LLDBLog::Step);257 if (log)258 log->PutCString("ThreadPlanStepThrough hit backstop breakpoint.");259 return true;260 }261 }262 }263 return false;264}265