source/Target/ThreadPlanStepThrough.cpp - llvm-project/lldb - Git at Google

 //===-- ThreadPlanStepThrough.cpp -----------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #include "lldb/Target/ThreadPlanStepThrough.h"
 #include "lldb/Breakpoint/Breakpoint.h"
 #include "lldb/Target/DynamicLoader.h"
 #include "lldb/Target/LanguageRuntime.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/RegisterContext.h"
 #include "lldb/Target/Target.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/Stream.h"

 using namespace lldb;
 using namespace lldb_private;

 // ThreadPlanStepThrough: If the current instruction is a trampoline, step
 // through it If it is the beginning of the prologue of a function, step
 // through that as well.

 ThreadPlanStepThrough::ThreadPlanStepThrough(Thread &thread,
                                              StackID &m_stack_id,
                                              bool stop_others)
     : ThreadPlan(ThreadPlan::eKindStepThrough,
                  "Step through trampolines and prologues", thread,
                  eVoteNoOpinion, eVoteNoOpinion),
       m_start_address(0), m_backstop_bkpt_id(LLDB_INVALID_BREAK_ID),
       m_backstop_addr(LLDB_INVALID_ADDRESS), m_return_stack_id(m_stack_id),
       m_stop_others(stop_others) {
   LookForPlanToStepThroughFromCurrentPC();

   // If we don't get a valid step through plan, don't bother to set up a
   // backstop.
   if (m_sub_plan_sp) {
     m_start_address = GetThread().GetRegisterContext()->GetPC(0);

     // We are going to return back to the concrete frame 1, we might pass by
     // some inlined code that we're in the middle of by doing this, but it's
     // easier than trying to figure out where the inlined code might return to.

     StackFrameSP return_frame_sp = thread.GetFrameWithStackID(m_stack_id);

     if (return_frame_sp) {
       m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(
           thread.CalculateTarget().get());
       Breakpoint *return_bp =
           m_process.GetTarget()
               .CreateBreakpoint(m_backstop_addr, true, false)
               .get();

       if (return_bp != nullptr) {
         if (return_bp->IsHardware() && !return_bp->HasResolvedLocations())
           m_could_not_resolve_hw_bp = true;
         return_bp->SetThreadID(m_tid);
         m_backstop_bkpt_id = return_bp->GetID();
         return_bp->SetBreakpointKind("step-through-backstop");
       }
       Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
       if (log) {
         LLDB_LOGF(log, "Setting backstop breakpoint %d at address: 0x%" PRIx64,
                   m_backstop_bkpt_id, m_backstop_addr);
       }
     }
   }
 }

 ThreadPlanStepThrough::~ThreadPlanStepThrough() { ClearBackstopBreakpoint(); }

 void ThreadPlanStepThrough::DidPush() {
   if (m_sub_plan_sp)
     PushPlan(m_sub_plan_sp);
 }

 void ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC() {
   Thread &thread = GetThread();
   DynamicLoader *loader = thread.GetProcess()->GetDynamicLoader();
   if (loader)
     m_sub_plan_sp = loader->GetStepThroughTrampolinePlan(thread, m_stop_others);

   // If the DynamicLoader was unable to provide us with a ThreadPlan, then we
   // try the LanguageRuntimes.
   if (!m_sub_plan_sp) {
     for (LanguageRuntime *runtime : m_process.GetLanguageRuntimes()) {
       m_sub_plan_sp =
           runtime->GetStepThroughTrampolinePlan(thread, m_stop_others);

       if (m_sub_plan_sp)
         break;
     }
   }

   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
   if (log) {
     lldb::addr_t current_address = GetThread().GetRegisterContext()->GetPC(0);
     if (m_sub_plan_sp) {
       StreamString s;
       m_sub_plan_sp->GetDescription(&s, lldb::eDescriptionLevelFull);
       LLDB_LOGF(log, "Found step through plan from 0x%" PRIx64 ": %s",
                 current_address, s.GetData());
     } else {
       LLDB_LOGF(log,
                 "Couldn't find step through plan from address 0x%" PRIx64 ".",
                 current_address);
     }
   }
 }

 void ThreadPlanStepThrough::GetDescription(Stream *s,
                                            lldb::DescriptionLevel level) {
   if (level == lldb::eDescriptionLevelBrief)
     s->Printf("Step through");
   else {
     s->PutCString("Stepping through trampoline code from: ");
     DumpAddress(s->AsRawOstream(), m_start_address, sizeof(addr_t));
     if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {
       s->Printf(" with backstop breakpoint ID: %d at address: ",
                 m_backstop_bkpt_id);
       DumpAddress(s->AsRawOstream(), m_backstop_addr, sizeof(addr_t));
     } else
       s->PutCString(" unable to set a backstop breakpoint.");
   }
 }

 bool ThreadPlanStepThrough::ValidatePlan(Stream *error) {
   if (m_could_not_resolve_hw_bp) {
     if (error)
       error->PutCString(
           "Could not create hardware breakpoint for thread plan.");
     return false;
   }

   if (m_backstop_bkpt_id == LLDB_INVALID_BREAK_ID) {
     if (error)
       error->PutCString("Could not create backstop breakpoint.");
     return false;
   }

   if (!m_sub_plan_sp.get()) {
     if (error)
       error->PutCString("Does not have a subplan.");
     return false;
   }

   return true;
 }

 bool ThreadPlanStepThrough::DoPlanExplainsStop(Event *event_ptr) {
   // If we have a sub-plan, it will have been asked first if we explain the
   // stop, and we won't get asked.  The only time we would be the one directly
   // asked this question is if we hit our backstop breakpoint.

   return HitOurBackstopBreakpoint();
 }

 bool ThreadPlanStepThrough::ShouldStop(Event *event_ptr) {
   // If we've already marked ourselves done, then we're done...
   if (IsPlanComplete())
     return true;

   // First, did we hit the backstop breakpoint?
   if (HitOurBackstopBreakpoint()) {
     SetPlanComplete(true);
     return true;
   }

   // If we don't have a sub-plan, then we're also done (can't see how we would
   // ever get here without a plan, but just in case.

   if (!m_sub_plan_sp) {
     SetPlanComplete();
     return true;
   }

   // If the current sub plan is not done, we don't want to stop.  Actually, we
   // probably won't ever get here in this state, since we generally won't get
   // asked any questions if out current sub-plan is not done...
   if (!m_sub_plan_sp->IsPlanComplete())
     return false;

   // If our current sub plan failed, then let's just run to our backstop.  If
   // we can't do that then just stop.
   if (!m_sub_plan_sp->PlanSucceeded()) {
     if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {
       m_sub_plan_sp.reset();
       return false;
     } else {
       SetPlanComplete(false);
       return true;
     }
   }

   // Next see if there is a specific step through plan at our current pc (these
   // might chain, for instance stepping through a dylib trampoline to the objc
   // dispatch function...)
   LookForPlanToStepThroughFromCurrentPC();
   if (m_sub_plan_sp) {
     PushPlan(m_sub_plan_sp);
     return false;
   } else {
     SetPlanComplete();
     return true;
   }
 }

 bool ThreadPlanStepThrough::StopOthers() { return m_stop_others; }

 StateType ThreadPlanStepThrough::GetPlanRunState() { return eStateRunning; }

 bool ThreadPlanStepThrough::DoWillResume(StateType resume_state,
                                          bool current_plan) {
   return true;
 }

 bool ThreadPlanStepThrough::WillStop() { return true; }

 void ThreadPlanStepThrough::ClearBackstopBreakpoint() {
   if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {
     m_process.GetTarget().RemoveBreakpointByID(m_backstop_bkpt_id);
     m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
     m_could_not_resolve_hw_bp = false;
   }
 }

 bool ThreadPlanStepThrough::MischiefManaged() {
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));

   if (!IsPlanComplete()) {
     return false;
   } else {
     LLDB_LOGF(log, "Completed step through step plan.");

     ClearBackstopBreakpoint();
     ThreadPlan::MischiefManaged();
     return true;
   }
 }

 bool ThreadPlanStepThrough::HitOurBackstopBreakpoint() {
   Thread &thread = GetThread();
   StopInfoSP stop_info_sp(thread.GetStopInfo());
   if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint) {
     break_id_t stop_value = (break_id_t)stop_info_sp->GetValue();
     BreakpointSiteSP cur_site_sp =
         m_process.GetBreakpointSiteList().FindByID(stop_value);
     if (cur_site_sp &&
         cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id)) {
       StackID cur_frame_zero_id = thread.GetStackFrameAtIndex(0)->GetStackID();

       if (cur_frame_zero_id == m_return_stack_id) {
         Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
         if (log)
           log->PutCString("ThreadPlanStepThrough hit backstop breakpoint.");
         return true;
       }
     }
   }
   return false;
 }
	//===-- ThreadPlanStepThrough.cpp -----------------------------------------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#include "lldb/Target/ThreadPlanStepThrough.h"
	#include "lldb/Breakpoint/Breakpoint.h"
	#include "lldb/Target/DynamicLoader.h"
	#include "lldb/Target/LanguageRuntime.h"
	#include "lldb/Target/Process.h"
	#include "lldb/Target/RegisterContext.h"
	#include "lldb/Target/Target.h"
	#include "lldb/Utility/Log.h"
	#include "lldb/Utility/Stream.h"

	using namespace lldb;
	using namespace lldb_private;

	// ThreadPlanStepThrough: If the current instruction is a trampoline, step
	// through it If it is the beginning of the prologue of a function, step
	// through that as well.

	ThreadPlanStepThrough::ThreadPlanStepThrough(Thread &thread,
	StackID &m_stack_id,
	bool stop_others)
	: ThreadPlan(ThreadPlan::eKindStepThrough,
	"Step through trampolines and prologues", thread,
	eVoteNoOpinion, eVoteNoOpinion),
	m_start_address(0), m_backstop_bkpt_id(LLDB_INVALID_BREAK_ID),
	m_backstop_addr(LLDB_INVALID_ADDRESS), m_return_stack_id(m_stack_id),
	m_stop_others(stop_others) {
	LookForPlanToStepThroughFromCurrentPC();

	// If we don't get a valid step through plan, don't bother to set up a
	// backstop.
	if (m_sub_plan_sp) {
	m_start_address = GetThread().GetRegisterContext()->GetPC(0);

	// We are going to return back to the concrete frame 1, we might pass by
	// some inlined code that we're in the middle of by doing this, but it's
	// easier than trying to figure out where the inlined code might return to.

	StackFrameSP return_frame_sp = thread.GetFrameWithStackID(m_stack_id);

	if (return_frame_sp) {
	m_backstop_addr = return_frame_sp->GetFrameCodeAddress().GetLoadAddress(
	thread.CalculateTarget().get());
	Breakpoint *return_bp =
	m_process.GetTarget()
	.CreateBreakpoint(m_backstop_addr, true, false)
	.get();

	if (return_bp != nullptr) {
	if (return_bp->IsHardware() && !return_bp->HasResolvedLocations())
	m_could_not_resolve_hw_bp = true;
	return_bp->SetThreadID(m_tid);
	m_backstop_bkpt_id = return_bp->GetID();
	return_bp->SetBreakpointKind("step-through-backstop");
	}
	Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
	if (log) {
	LLDB_LOGF(log, "Setting backstop breakpoint %d at address: 0x%" PRIx64,
	m_backstop_bkpt_id, m_backstop_addr);
	}
	}
	}
	}

	ThreadPlanStepThrough::~ThreadPlanStepThrough() { ClearBackstopBreakpoint(); }

	void ThreadPlanStepThrough::DidPush() {
	if (m_sub_plan_sp)
	PushPlan(m_sub_plan_sp);
	}

	void ThreadPlanStepThrough::LookForPlanToStepThroughFromCurrentPC() {
	Thread &thread = GetThread();
	DynamicLoader *loader = thread.GetProcess()->GetDynamicLoader();
	if (loader)
	m_sub_plan_sp = loader->GetStepThroughTrampolinePlan(thread, m_stop_others);

	// If the DynamicLoader was unable to provide us with a ThreadPlan, then we
	// try the LanguageRuntimes.
	if (!m_sub_plan_sp) {
	for (LanguageRuntime *runtime : m_process.GetLanguageRuntimes()) {
	m_sub_plan_sp =
	runtime->GetStepThroughTrampolinePlan(thread, m_stop_others);

	if (m_sub_plan_sp)
	break;
	}
	}

	Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
	if (log) {
	lldb::addr_t current_address = GetThread().GetRegisterContext()->GetPC(0);
	if (m_sub_plan_sp) {
	StreamString s;
	m_sub_plan_sp->GetDescription(&s, lldb::eDescriptionLevelFull);
	LLDB_LOGF(log, "Found step through plan from 0x%" PRIx64 ": %s",
	current_address, s.GetData());
	} else {
	LLDB_LOGF(log,
	"Couldn't find step through plan from address 0x%" PRIx64 ".",
	current_address);
	}
	}
	}

	void ThreadPlanStepThrough::GetDescription(Stream *s,
	lldb::DescriptionLevel level) {
	if (level == lldb::eDescriptionLevelBrief)
	s->Printf("Step through");
	else {
	s->PutCString("Stepping through trampoline code from: ");
	DumpAddress(s->AsRawOstream(), m_start_address, sizeof(addr_t));
	if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {
	s->Printf(" with backstop breakpoint ID: %d at address: ",
	m_backstop_bkpt_id);
	DumpAddress(s->AsRawOstream(), m_backstop_addr, sizeof(addr_t));
	} else
	s->PutCString(" unable to set a backstop breakpoint.");
	}
	}

	bool ThreadPlanStepThrough::ValidatePlan(Stream *error) {
	if (m_could_not_resolve_hw_bp) {
	if (error)
	error->PutCString(
	"Could not create hardware breakpoint for thread plan.");
	return false;
	}

	if (m_backstop_bkpt_id == LLDB_INVALID_BREAK_ID) {
	if (error)
	error->PutCString("Could not create backstop breakpoint.");
	return false;
	}

	if (!m_sub_plan_sp.get()) {
	if (error)
	error->PutCString("Does not have a subplan.");
	return false;
	}

	return true;
	}

	bool ThreadPlanStepThrough::DoPlanExplainsStop(Event *event_ptr) {
	// If we have a sub-plan, it will have been asked first if we explain the
	// stop, and we won't get asked. The only time we would be the one directly
	// asked this question is if we hit our backstop breakpoint.

	return HitOurBackstopBreakpoint();
	}

	bool ThreadPlanStepThrough::ShouldStop(Event *event_ptr) {
	// If we've already marked ourselves done, then we're done...
	if (IsPlanComplete())
	return true;

	// First, did we hit the backstop breakpoint?
	if (HitOurBackstopBreakpoint()) {
	SetPlanComplete(true);
	return true;
	}

	// If we don't have a sub-plan, then we're also done (can't see how we would
	// ever get here without a plan, but just in case.

	if (!m_sub_plan_sp) {
	SetPlanComplete();
	return true;
	}

	// If the current sub plan is not done, we don't want to stop. Actually, we
	// probably won't ever get here in this state, since we generally won't get
	// asked any questions if out current sub-plan is not done...
	if (!m_sub_plan_sp->IsPlanComplete())
	return false;

	// If our current sub plan failed, then let's just run to our backstop. If
	// we can't do that then just stop.
	if (!m_sub_plan_sp->PlanSucceeded()) {
	if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {
	m_sub_plan_sp.reset();
	return false;
	} else {
	SetPlanComplete(false);
	return true;
	}
	}

	// Next see if there is a specific step through plan at our current pc (these
	// might chain, for instance stepping through a dylib trampoline to the objc
	// dispatch function...)
	LookForPlanToStepThroughFromCurrentPC();
	if (m_sub_plan_sp) {
	PushPlan(m_sub_plan_sp);
	return false;
	} else {
	SetPlanComplete();
	return true;
	}
	}

	bool ThreadPlanStepThrough::StopOthers() { return m_stop_others; }

	StateType ThreadPlanStepThrough::GetPlanRunState() { return eStateRunning; }

	bool ThreadPlanStepThrough::DoWillResume(StateType resume_state,
	bool current_plan) {
	return true;
	}

	bool ThreadPlanStepThrough::WillStop() { return true; }

	void ThreadPlanStepThrough::ClearBackstopBreakpoint() {
	if (m_backstop_bkpt_id != LLDB_INVALID_BREAK_ID) {
	m_process.GetTarget().RemoveBreakpointByID(m_backstop_bkpt_id);
	m_backstop_bkpt_id = LLDB_INVALID_BREAK_ID;
	m_could_not_resolve_hw_bp = false;
	}
	}

	bool ThreadPlanStepThrough::MischiefManaged() {
	Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));

	if (!IsPlanComplete()) {
	return false;
	} else {
	LLDB_LOGF(log, "Completed step through step plan.");

	ClearBackstopBreakpoint();
	ThreadPlan::MischiefManaged();
	return true;
	}
	}

	bool ThreadPlanStepThrough::HitOurBackstopBreakpoint() {
	Thread &thread = GetThread();
	StopInfoSP stop_info_sp(thread.GetStopInfo());
	if (stop_info_sp && stop_info_sp->GetStopReason() == eStopReasonBreakpoint) {
	break_id_t stop_value = (break_id_t)stop_info_sp->GetValue();
	BreakpointSiteSP cur_site_sp =
	m_process.GetBreakpointSiteList().FindByID(stop_value);
	if (cur_site_sp &&
	cur_site_sp->IsBreakpointAtThisSite(m_backstop_bkpt_id)) {
	StackID cur_frame_zero_id = thread.GetStackFrameAtIndex(0)->GetStackID();

	if (cur_frame_zero_id == m_return_stack_id) {
	Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
	if (log)
	log->PutCString("ThreadPlanStepThrough hit backstop breakpoint.");
	return true;
	}
	}
	}
	return false;
	}