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llvm-project/lldb/source/Target/ThreadPlanStepOut.cpp

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//===-- ThreadPlanStepOut.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/ThreadPlanStepOut.h"
#include "lldb/Breakpoint/Breakpoint.h"
#include "lldb/Core/Value.h"
#include "lldb/Core/ValueObjectConstResult.h"
#include "lldb/Symbol/Block.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/ThreadPlanStepOverRange.h"
#include "lldb/Target/ThreadPlanStepThrough.h"
#include "lldb/Utility/Log.h"
#include <memory>
using namespace lldb;
using namespace lldb_private;
uint32_t ThreadPlanStepOut::s_default_flag_values = 0;
// ThreadPlanStepOut: Step out of the current frame
ThreadPlanStepOut::ThreadPlanStepOut(
Thread &thread, SymbolContext *context, bool first_insn, bool stop_others,
Vote stop_vote, Vote run_vote, uint32_t frame_idx,
LazyBool step_out_avoids_code_without_debug_info,
bool continue_to_next_branch, bool gather_return_value)
: ThreadPlan(ThreadPlan::eKindStepOut, "Step out", thread, stop_vote,
run_vote),
ThreadPlanShouldStopHere(this), m_step_from_insn(LLDB_INVALID_ADDRESS),
m_return_bp_id(LLDB_INVALID_BREAK_ID),
m_return_addr(LLDB_INVALID_ADDRESS), m_stop_others(stop_others),
m_immediate_step_from_function(nullptr),
m_calculate_return_value(gather_return_value) {
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
SetFlagsToDefault();
SetupAvoidNoDebug(step_out_avoids_code_without_debug_info);
m_step_from_insn = m_thread.GetRegisterContext()->GetPC(0);
uint32_t return_frame_index = frame_idx + 1;
StackFrameSP return_frame_sp(
m_thread.GetStackFrameAtIndex(return_frame_index));
StackFrameSP immediate_return_from_sp(
m_thread.GetStackFrameAtIndex(frame_idx));
if (!return_frame_sp || !immediate_return_from_sp)
return; // we can't do anything here. ValidatePlan() will return false.
// While stepping out, behave as-if artificial frames are not present.
while (return_frame_sp->IsArtificial()) {
m_stepped_past_frames.push_back(return_frame_sp);
++return_frame_index;
return_frame_sp = m_thread.GetStackFrameAtIndex(return_frame_index);
// We never expect to see an artificial frame without a regular ancestor.
// If this happens, log the issue and defensively refuse to step out.
if (!return_frame_sp) {
LLDB_LOG(log, "Can't step out of frame with artificial ancestors");
return;
}
}
m_step_out_to_id = return_frame_sp->GetStackID();
m_immediate_step_from_id = immediate_return_from_sp->GetStackID();
// If the frame directly below the one we are returning to is inlined, we
// have to be a little more careful. It is non-trivial to determine the real
// "return code address" for an inlined frame, so we have to work our way to
// that frame and then step out.
if (immediate_return_from_sp->IsInlined()) {
if (frame_idx > 0) {
// First queue a plan that gets us to this inlined frame, and when we get
// there we'll queue a second plan that walks us out of this frame.
m_step_out_to_inline_plan_sp = std::make_shared<ThreadPlanStepOut>(
m_thread, nullptr, false, stop_others, eVoteNoOpinion, eVoteNoOpinion,
frame_idx - 1, eLazyBoolNo, continue_to_next_branch);
static_cast<ThreadPlanStepOut *>(m_step_out_to_inline_plan_sp.get())
->SetShouldStopHereCallbacks(nullptr, nullptr);
m_step_out_to_inline_plan_sp->SetPrivate(true);
} else {
// If we're already at the inlined frame we're stepping through, then
// just do that now.
QueueInlinedStepPlan(false);
}
} else {
// Find the return address and set a breakpoint there:
// FIXME - can we do this more securely if we know first_insn?
Address return_address(return_frame_sp->GetFrameCodeAddress());
if (continue_to_next_branch) {
SymbolContext return_address_sc;
AddressRange range;
Address return_address_decr_pc = return_address;
if (return_address_decr_pc.GetOffset() > 0)
return_address_decr_pc.Slide(-1);
return_address_decr_pc.CalculateSymbolContext(
&return_address_sc, lldb::eSymbolContextLineEntry);
if (return_address_sc.line_entry.IsValid()) {
const bool include_inlined_functions = false;
range = return_address_sc.line_entry.GetSameLineContiguousAddressRange(
include_inlined_functions);
if (range.GetByteSize() > 0) {
return_address =
m_thread.GetProcess()->AdvanceAddressToNextBranchInstruction(
return_address, range);
}
}
}
m_return_addr =
return_address.GetLoadAddress(&m_thread.GetProcess()->GetTarget());
if (m_return_addr == LLDB_INVALID_ADDRESS)
return;
// Perform some additional validation on the return address.
uint32_t permissions = 0;
if (!m_thread.GetProcess()->GetLoadAddressPermissions(m_return_addr,
permissions)) {
m_constructor_errors.Printf("Return address (0x%" PRIx64
") permissions not found.",
m_return_addr);
LLDB_LOGF(log, "ThreadPlanStepOut(%p): %s", static_cast<void *>(this),
m_constructor_errors.GetData());
} else if (!(permissions & ePermissionsExecutable)) {
m_constructor_errors.Printf("Return address (0x%" PRIx64
") did not point to executable memory.",
m_return_addr);
LLDB_LOGF(log, "ThreadPlanStepOut(%p): %s", static_cast<void *>(this),
m_constructor_errors.GetData());
return;
}
Breakpoint *return_bp = m_thread.CalculateTarget()
->CreateBreakpoint(m_return_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_thread.GetID());
m_return_bp_id = return_bp->GetID();
return_bp->SetBreakpointKind("step-out");
}
if (immediate_return_from_sp) {
const SymbolContext &sc =
immediate_return_from_sp->GetSymbolContext(eSymbolContextFunction);
if (sc.function) {
m_immediate_step_from_function = sc.function;
}
}
}
}
void ThreadPlanStepOut::SetupAvoidNoDebug(
LazyBool step_out_avoids_code_without_debug_info) {
bool avoid_nodebug = true;
switch (step_out_avoids_code_without_debug_info) {
case eLazyBoolYes:
avoid_nodebug = true;
break;
case eLazyBoolNo:
avoid_nodebug = false;
break;
case eLazyBoolCalculate:
avoid_nodebug = m_thread.GetStepOutAvoidsNoDebug();
break;
}
if (avoid_nodebug)
GetFlags().Set(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
else
GetFlags().Clear(ThreadPlanShouldStopHere::eStepOutAvoidNoDebug);
}
void ThreadPlanStepOut::DidPush() {
if (m_step_out_to_inline_plan_sp)
m_thread.QueueThreadPlan(m_step_out_to_inline_plan_sp, false);
else if (m_step_through_inline_plan_sp)
m_thread.QueueThreadPlan(m_step_through_inline_plan_sp, false);
}
ThreadPlanStepOut::~ThreadPlanStepOut() {
if (m_return_bp_id != LLDB_INVALID_BREAK_ID)
m_thread.CalculateTarget()->RemoveBreakpointByID(m_return_bp_id);
}
void ThreadPlanStepOut::GetDescription(Stream *s,
lldb::DescriptionLevel level) {
if (level == lldb::eDescriptionLevelBrief)
s->Printf("step out");
else {
if (m_step_out_to_inline_plan_sp)
s->Printf("Stepping out to inlined frame so we can walk through it.");
else if (m_step_through_inline_plan_sp)
s->Printf("Stepping out by stepping through inlined function.");
else {
s->Printf("Stepping out from ");
Address tmp_address;
if (tmp_address.SetLoadAddress(m_step_from_insn, &GetTarget())) {
tmp_address.Dump(s, &GetThread(), Address::DumpStyleResolvedDescription,
Address::DumpStyleLoadAddress);
} else {
s->Printf("address 0x%" PRIx64 "", (uint64_t)m_step_from_insn);
}
// FIXME: find some useful way to present the m_return_id, since there may
// be multiple copies of the
// same function on the stack.
s->Printf(" returning to frame at ");
if (tmp_address.SetLoadAddress(m_return_addr, &GetTarget())) {
tmp_address.Dump(s, &GetThread(), Address::DumpStyleResolvedDescription,
Address::DumpStyleLoadAddress);
} else {
s->Printf("address 0x%" PRIx64 "", (uint64_t)m_return_addr);
}
if (level == eDescriptionLevelVerbose)
s->Printf(" using breakpoint site %d", m_return_bp_id);
}
}
s->Printf("\n");
for (StackFrameSP frame_sp : m_stepped_past_frames) {
s->Printf("Stepped out past: ");
frame_sp->DumpUsingSettingsFormat(s);
}
}
bool ThreadPlanStepOut::ValidatePlan(Stream *error) {
if (m_step_out_to_inline_plan_sp)
return m_step_out_to_inline_plan_sp->ValidatePlan(error);
if (m_step_through_inline_plan_sp)
return m_step_through_inline_plan_sp->ValidatePlan(error);
if (m_could_not_resolve_hw_bp) {
if (error)
error->PutCString(
"Could not create hardware breakpoint for thread plan.");
return false;
}
if (m_return_bp_id == LLDB_INVALID_BREAK_ID) {
if (error) {
error->PutCString("Could not create return address breakpoint.");
if (m_constructor_errors.GetSize() > 0) {
error->PutCString(" ");
error->PutCString(m_constructor_errors.GetString());
}
}
return false;
}
return true;
}
bool ThreadPlanStepOut::DoPlanExplainsStop(Event *event_ptr) {
// If the step out plan is done, then we just need to step through the
// inlined frame.
if (m_step_out_to_inline_plan_sp) {
return m_step_out_to_inline_plan_sp->MischiefManaged();
} else if (m_step_through_inline_plan_sp) {
if (m_step_through_inline_plan_sp->MischiefManaged()) {
CalculateReturnValue();
SetPlanComplete();
return true;
} else
return false;
} else if (m_step_out_further_plan_sp) {
return m_step_out_further_plan_sp->MischiefManaged();
}
// We don't explain signals or breakpoints (breakpoints that handle stepping
// in or out will be handled by a child plan.
StopInfoSP stop_info_sp = GetPrivateStopInfo();
if (stop_info_sp) {
StopReason reason = stop_info_sp->GetStopReason();
if (reason == eStopReasonBreakpoint) {
// If this is OUR breakpoint, we're fine, otherwise we don't know why
// this happened...
BreakpointSiteSP site_sp(
m_thread.GetProcess()->GetBreakpointSiteList().FindByID(
stop_info_sp->GetValue()));
if (site_sp && site_sp->IsBreakpointAtThisSite(m_return_bp_id)) {
bool done;
StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
if (m_step_out_to_id == frame_zero_id)
done = true;
else if (m_step_out_to_id < frame_zero_id) {
// Either we stepped past the breakpoint, or the stack ID calculation
// was incorrect and we should probably stop.
done = true;
} else {
done = (m_immediate_step_from_id < frame_zero_id);
}
if (done) {
if (InvokeShouldStopHereCallback(eFrameCompareOlder, m_status)) {
CalculateReturnValue();
SetPlanComplete();
}
}
// If there was only one owner, then we're done. But if we also hit
// some user breakpoint on our way out, we should mark ourselves as
// done, but also not claim to explain the stop, since it is more
// important to report the user breakpoint than the step out
// completion.
if (site_sp->GetNumberOfOwners() == 1)
return true;
}
return false;
} else if (IsUsuallyUnexplainedStopReason(reason))
return false;
else
return true;
}
return true;
}
bool ThreadPlanStepOut::ShouldStop(Event *event_ptr) {
if (IsPlanComplete())
return true;
bool done = false;
if (m_step_out_to_inline_plan_sp) {
if (m_step_out_to_inline_plan_sp->MischiefManaged()) {
// Now step through the inlined stack we are in:
if (QueueInlinedStepPlan(true)) {
// If we can't queue a plan to do this, then just call ourselves done.
m_step_out_to_inline_plan_sp.reset();
SetPlanComplete(false);
return true;
} else
done = true;
} else
return m_step_out_to_inline_plan_sp->ShouldStop(event_ptr);
} else if (m_step_through_inline_plan_sp) {
if (m_step_through_inline_plan_sp->MischiefManaged())
done = true;
else
return m_step_through_inline_plan_sp->ShouldStop(event_ptr);
} else if (m_step_out_further_plan_sp) {
if (m_step_out_further_plan_sp->MischiefManaged())
m_step_out_further_plan_sp.reset();
else
return m_step_out_further_plan_sp->ShouldStop(event_ptr);
}
if (!done) {
StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
done = !(frame_zero_id < m_step_out_to_id);
}
// The normal step out computations think we are done, so all we need to do
// is consult the ShouldStopHere, and we are done.
if (done) {
if (InvokeShouldStopHereCallback(eFrameCompareOlder, m_status)) {
CalculateReturnValue();
SetPlanComplete();
} else {
m_step_out_further_plan_sp =
QueueStepOutFromHerePlan(m_flags, eFrameCompareOlder, m_status);
done = false;
}
}
return done;
}
bool ThreadPlanStepOut::StopOthers() { return m_stop_others; }
StateType ThreadPlanStepOut::GetPlanRunState() { return eStateRunning; }
bool ThreadPlanStepOut::DoWillResume(StateType resume_state,
bool current_plan) {
if (m_step_out_to_inline_plan_sp || m_step_through_inline_plan_sp)
return true;
if (m_return_bp_id == LLDB_INVALID_BREAK_ID)
return false;
if (current_plan) {
Breakpoint *return_bp =
m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
if (return_bp != nullptr)
return_bp->SetEnabled(true);
}
return true;
}
bool ThreadPlanStepOut::WillStop() {
if (m_return_bp_id != LLDB_INVALID_BREAK_ID) {
Breakpoint *return_bp =
m_thread.CalculateTarget()->GetBreakpointByID(m_return_bp_id).get();
if (return_bp != nullptr)
return_bp->SetEnabled(false);
}
return true;
}
bool ThreadPlanStepOut::MischiefManaged() {
if (IsPlanComplete()) {
// Did I reach my breakpoint? If so I'm done.
//
// I also check the stack depth, since if we've blown past the breakpoint
// for some
// reason and we're now stopping for some other reason altogether, then
// we're done with this step out operation.
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
if (log)
LLDB_LOGF(log, "Completed step out plan.");
if (m_return_bp_id != LLDB_INVALID_BREAK_ID) {
m_thread.CalculateTarget()->RemoveBreakpointByID(m_return_bp_id);
m_return_bp_id = LLDB_INVALID_BREAK_ID;
}
ThreadPlan::MischiefManaged();
return true;
} else {
return false;
}
}
bool ThreadPlanStepOut::QueueInlinedStepPlan(bool queue_now) {
// Now figure out the range of this inlined block, and set up a "step through
// range" plan for that. If we've been provided with a context, then use the
// block in that context.
StackFrameSP immediate_return_from_sp(m_thread.GetStackFrameAtIndex(0));
if (!immediate_return_from_sp)
return false;
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
if (log) {
StreamString s;
immediate_return_from_sp->Dump(&s, true, false);
LLDB_LOGF(log, "Queuing inlined frame to step past: %s.", s.GetData());
}
Block *from_block = immediate_return_from_sp->GetFrameBlock();
if (from_block) {
Block *inlined_block = from_block->GetContainingInlinedBlock();
if (inlined_block) {
size_t num_ranges = inlined_block->GetNumRanges();
AddressRange inline_range;
if (inlined_block->GetRangeAtIndex(0, inline_range)) {
SymbolContext inlined_sc;
inlined_block->CalculateSymbolContext(&inlined_sc);
inlined_sc.target_sp = GetTarget().shared_from_this();
RunMode run_mode =
m_stop_others ? lldb::eOnlyThisThread : lldb::eAllThreads;
const LazyBool avoid_no_debug = eLazyBoolNo;
m_step_through_inline_plan_sp =
std::make_shared<ThreadPlanStepOverRange>(
m_thread, inline_range, inlined_sc, run_mode, avoid_no_debug);
ThreadPlanStepOverRange *step_through_inline_plan_ptr =
static_cast<ThreadPlanStepOverRange *>(
m_step_through_inline_plan_sp.get());
m_step_through_inline_plan_sp->SetPrivate(true);
step_through_inline_plan_ptr->SetOkayToDiscard(true);
StreamString errors;
if (!step_through_inline_plan_ptr->ValidatePlan(&errors)) {
// FIXME: Log this failure.
delete step_through_inline_plan_ptr;
return false;
}
for (size_t i = 1; i < num_ranges; i++) {
if (inlined_block->GetRangeAtIndex(i, inline_range))
step_through_inline_plan_ptr->AddRange(inline_range);
}
if (queue_now)
m_thread.QueueThreadPlan(m_step_through_inline_plan_sp, false);
return true;
}
}
}
return false;
}
void ThreadPlanStepOut::CalculateReturnValue() {
if (m_return_valobj_sp)
return;
if (!m_calculate_return_value)
return;
if (m_immediate_step_from_function != nullptr) {
CompilerType return_compiler_type =
m_immediate_step_from_function->GetCompilerType()
.GetFunctionReturnType();
if (return_compiler_type) {
lldb::ABISP abi_sp = m_thread.GetProcess()->GetABI();
if (abi_sp)
m_return_valobj_sp =
abi_sp->GetReturnValueObject(m_thread, return_compiler_type);
}
}
}
bool ThreadPlanStepOut::IsPlanStale() {
// If we are still lower on the stack than the frame we are returning to,
// then there's something for us to do. Otherwise, we're stale.
StackID frame_zero_id = m_thread.GetStackFrameAtIndex(0)->GetStackID();
return !(frame_zero_id < m_step_out_to_id);
}
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