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

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//===-- StopInfo.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 <string>
#include "lldb/Breakpoint/Breakpoint.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Breakpoint/StoppointCallbackContext.h"
#include "lldb/Breakpoint/Watchpoint.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Expression/UserExpression.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/UnixSignals.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/StreamString.h"
using namespace lldb;
using namespace lldb_private;
StopInfo::StopInfo(Thread &thread, uint64_t value)
: m_thread_wp(thread.shared_from_this()),
m_stop_id(thread.GetProcess()->GetStopID()),
m_resume_id(thread.GetProcess()->GetResumeID()), m_value(value),
m_description(), m_override_should_notify(eLazyBoolCalculate),
m_override_should_stop(eLazyBoolCalculate), m_extended_info() {}
bool StopInfo::IsValid() const {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
return thread_sp->GetProcess()->GetStopID() == m_stop_id;
return false;
}
void StopInfo::MakeStopInfoValid() {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
m_stop_id = thread_sp->GetProcess()->GetStopID();
m_resume_id = thread_sp->GetProcess()->GetResumeID();
}
}
bool StopInfo::HasTargetRunSinceMe() {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
lldb::StateType ret_type = thread_sp->GetProcess()->GetPrivateState();
if (ret_type == eStateRunning) {
return true;
} else if (ret_type == eStateStopped) {
// This is a little tricky. We want to count "run and stopped again
// before you could ask this question as a "TRUE" answer to
// HasTargetRunSinceMe. But we don't want to include any running of the
// target done for expressions. So we track both resumes, and resumes
// caused by expressions, and check if there are any resumes
// NOT caused
// by expressions.
uint32_t curr_resume_id = thread_sp->GetProcess()->GetResumeID();
uint32_t last_user_expression_id =
thread_sp->GetProcess()->GetLastUserExpressionResumeID();
if (curr_resume_id == m_resume_id) {
return false;
} else if (curr_resume_id > last_user_expression_id) {
return true;
}
}
}
return false;
}
// StopInfoBreakpoint
namespace lldb_private {
class StopInfoBreakpoint : public StopInfo {
public:
StopInfoBreakpoint(Thread &thread, break_id_t break_id)
: StopInfo(thread, break_id), m_should_stop(false),
m_should_stop_is_valid(false), m_should_perform_action(true),
m_address(LLDB_INVALID_ADDRESS), m_break_id(LLDB_INVALID_BREAK_ID),
m_was_one_shot(false) {
StoreBPInfo();
}
StopInfoBreakpoint(Thread &thread, break_id_t break_id, bool should_stop)
: StopInfo(thread, break_id), m_should_stop(should_stop),
m_should_stop_is_valid(true), m_should_perform_action(true),
m_address(LLDB_INVALID_ADDRESS), m_break_id(LLDB_INVALID_BREAK_ID),
m_was_one_shot(false) {
StoreBPInfo();
}
~StopInfoBreakpoint() override = default;
void StoreBPInfo() {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
BreakpointSiteSP bp_site_sp(
thread_sp->GetProcess()->GetBreakpointSiteList().FindByID(m_value));
if (bp_site_sp) {
if (bp_site_sp->GetNumberOfOwners() == 1) {
BreakpointLocationSP bp_loc_sp = bp_site_sp->GetOwnerAtIndex(0);
if (bp_loc_sp) {
m_break_id = bp_loc_sp->GetBreakpoint().GetID();
m_was_one_shot = bp_loc_sp->GetBreakpoint().IsOneShot();
}
}
m_address = bp_site_sp->GetLoadAddress();
}
}
}
bool IsValidForOperatingSystemThread(Thread &thread) override {
ProcessSP process_sp(thread.GetProcess());
if (process_sp) {
BreakpointSiteSP bp_site_sp(
process_sp->GetBreakpointSiteList().FindByID(m_value));
if (bp_site_sp)
return bp_site_sp->ValidForThisThread(thread);
}
return false;
}
StopReason GetStopReason() const override { return eStopReasonBreakpoint; }
bool ShouldStopSynchronous(Event *event_ptr) override {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
if (!m_should_stop_is_valid) {
// Only check once if we should stop at a breakpoint
BreakpointSiteSP bp_site_sp(
thread_sp->GetProcess()->GetBreakpointSiteList().FindByID(m_value));
if (bp_site_sp) {
ExecutionContext exe_ctx(thread_sp->GetStackFrameAtIndex(0));
StoppointCallbackContext context(event_ptr, exe_ctx, true);
bp_site_sp->BumpHitCounts();
m_should_stop = bp_site_sp->ShouldStop(&context);
} else {
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
LLDB_LOGF(log,
"Process::%s could not find breakpoint site id: %" PRId64
"...",
__FUNCTION__, m_value);
m_should_stop = true;
}
m_should_stop_is_valid = true;
}
return m_should_stop;
}
return false;
}
bool DoShouldNotify(Event *event_ptr) override {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
BreakpointSiteSP bp_site_sp(
thread_sp->GetProcess()->GetBreakpointSiteList().FindByID(m_value));
if (bp_site_sp) {
bool all_internal = true;
for (uint32_t i = 0; i < bp_site_sp->GetNumberOfOwners(); i++) {
if (!bp_site_sp->GetOwnerAtIndex(i)->GetBreakpoint().IsInternal()) {
all_internal = false;
break;
}
}
return !all_internal;
}
}
return true;
}
const char *GetDescription() override {
if (m_description.empty()) {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
BreakpointSiteSP bp_site_sp(
thread_sp->GetProcess()->GetBreakpointSiteList().FindByID(m_value));
if (bp_site_sp) {
StreamString strm;
// If we have just hit an internal breakpoint, and it has a kind
// description, print that instead of the full breakpoint printing:
if (bp_site_sp->IsInternal()) {
size_t num_owners = bp_site_sp->GetNumberOfOwners();
for (size_t idx = 0; idx < num_owners; idx++) {
const char *kind = bp_site_sp->GetOwnerAtIndex(idx)
->GetBreakpoint()
.GetBreakpointKind();
if (kind != nullptr) {
m_description.assign(kind);
return kind;
}
}
}
strm.Printf("breakpoint ");
bp_site_sp->GetDescription(&strm, eDescriptionLevelBrief);
m_description = std::string(strm.GetString());
} else {
StreamString strm;
if (m_break_id != LLDB_INVALID_BREAK_ID) {
BreakpointSP break_sp =
thread_sp->GetProcess()->GetTarget().GetBreakpointByID(
m_break_id);
if (break_sp) {
if (break_sp->IsInternal()) {
const char *kind = break_sp->GetBreakpointKind();
if (kind)
strm.Printf("internal %s breakpoint(%d).", kind, m_break_id);
else
strm.Printf("internal breakpoint(%d).", m_break_id);
} else {
strm.Printf("breakpoint %d.", m_break_id);
}
} else {
if (m_was_one_shot)
strm.Printf("one-shot breakpoint %d", m_break_id);
else
strm.Printf("breakpoint %d which has been deleted.",
m_break_id);
}
} else if (m_address == LLDB_INVALID_ADDRESS)
strm.Printf("breakpoint site %" PRIi64
" which has been deleted - unknown address",
m_value);
else
strm.Printf("breakpoint site %" PRIi64
" which has been deleted - was at 0x%" PRIx64,
m_value, m_address);
m_description = std::string(strm.GetString());
}
}
}
return m_description.c_str();
}
protected:
bool ShouldStop(Event *event_ptr) override {
// This just reports the work done by PerformAction or the synchronous
// stop. It should only ever get called after they have had a chance to
// run.
assert(m_should_stop_is_valid);
return m_should_stop;
}
void PerformAction(Event *event_ptr) override {
if (!m_should_perform_action)
return;
m_should_perform_action = false;
bool internal_breakpoint = true;
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
Log *log = lldb_private::GetLogIfAnyCategoriesSet(
LIBLLDB_LOG_BREAKPOINTS | LIBLLDB_LOG_STEP);
if (!thread_sp->IsValid()) {
// This shouldn't ever happen, but just in case, don't do more harm.
if (log) {
LLDB_LOGF(log, "PerformAction got called with an invalid thread.");
}
m_should_stop = true;
m_should_stop_is_valid = true;
return;
}
BreakpointSiteSP bp_site_sp(
thread_sp->GetProcess()->GetBreakpointSiteList().FindByID(m_value));
std::unordered_set<break_id_t> precondition_breakpoints;
if (bp_site_sp) {
// Let's copy the owners list out of the site and store them in a local
// list. That way if one of the breakpoint actions changes the site,
// then we won't be operating on a bad list.
BreakpointLocationCollection site_locations;
size_t num_owners = bp_site_sp->CopyOwnersList(site_locations);
if (num_owners == 0) {
m_should_stop = true;
} else {
// We go through each location, and test first its precondition -
// this overrides everything. Note, we only do this once per
// breakpoint - not once per location... Then check the condition.
// If the condition says to stop, then we run the callback for that
// location. If that callback says to stop as well, then we set
// m_should_stop to true; we are going to stop. But we still want to
// give all the breakpoints whose conditions say we are going to stop
// a chance to run their callbacks. Of course if any callback
// restarts the target by putting "continue" in the callback, then
// we're going to restart, without running the rest of the callbacks.
// And in this case we will end up not stopping even if another
// location said we should stop. But that's better than not running
// all the callbacks.
// There's one other complication here. We may have run an async
// breakpoint callback that said we should stop. We only want to
// override that if another breakpoint action says we shouldn't
// stop. If nobody else has an opinion, then we should stop if the
// async callback says we should. An example of this is the async
// shared library load notification breakpoint and the setting
// stop-on-sharedlibrary-events.
// We'll keep the async value in async_should_stop, and track whether
// anyone said we should NOT stop in actually_said_continue.
bool async_should_stop = false;
if (m_should_stop_is_valid)
async_should_stop = m_should_stop;
bool actually_said_continue = false;
m_should_stop = false;
// We don't select threads as we go through them testing breakpoint
// conditions and running commands. So we need to set the thread for
// expression evaluation here:
ThreadList::ExpressionExecutionThreadPusher thread_pusher(thread_sp);
ExecutionContext exe_ctx(thread_sp->GetStackFrameAtIndex(0));
Process *process = exe_ctx.GetProcessPtr();
if (process->GetModIDRef().IsLastResumeForUserExpression()) {
// If we are in the middle of evaluating an expression, don't run
// asynchronous breakpoint commands or expressions. That could
// lead to infinite recursion if the command or condition re-calls
// the function with this breakpoint.
// TODO: We can keep a list of the breakpoints we've seen while
// running expressions in the nested
// PerformAction calls that can arise when the action runs a
// function that hits another breakpoint, and only stop running
// commands when we see the same breakpoint hit a second time.
m_should_stop_is_valid = true;
// It is possible that the user has a breakpoint at the same site
// as the completed plan had (e.g. user has a breakpoint
// on a module entry point, and `ThreadPlanCallFunction` ends
// also there). We can't find an internal breakpoint in the loop
// later because it was already removed on the plan completion.
// So check if the plan was completed, and stop if so.
if (thread_sp->CompletedPlanOverridesBreakpoint()) {
m_should_stop = true;
thread_sp->ResetStopInfo();
return;
}
LLDB_LOGF(log, "StopInfoBreakpoint::PerformAction - Hit a "
"breakpoint while running an expression,"
" not running commands to avoid recursion.");
bool ignoring_breakpoints =
process->GetIgnoreBreakpointsInExpressions();
if (ignoring_breakpoints) {
m_should_stop = false;
// Internal breakpoints will always stop.
for (size_t j = 0; j < num_owners; j++) {
lldb::BreakpointLocationSP bp_loc_sp =
bp_site_sp->GetOwnerAtIndex(j);
if (bp_loc_sp->GetBreakpoint().IsInternal()) {
m_should_stop = true;
break;
}
}
} else {
m_should_stop = true;
}
LLDB_LOGF(log,
"StopInfoBreakpoint::PerformAction - in expression, "
"continuing: %s.",
m_should_stop ? "true" : "false");
process->GetTarget().GetDebugger().GetAsyncOutputStream()->Printf(
"Warning: hit breakpoint while running function, skipping "
"commands and conditions to prevent recursion.\n");
return;
}
StoppointCallbackContext context(event_ptr, exe_ctx, false);
// For safety's sake let's also grab an extra reference to the
// breakpoint owners of the locations we're going to examine, since
// the locations are going to have to get back to their breakpoints,
// and the locations don't keep their owners alive. I'm just
// sticking the BreakpointSP's in a vector since I'm only using it to
// locally increment their retain counts.
std::vector<lldb::BreakpointSP> location_owners;
for (size_t j = 0; j < num_owners; j++) {
BreakpointLocationSP loc(site_locations.GetByIndex(j));
location_owners.push_back(loc->GetBreakpoint().shared_from_this());
}
for (size_t j = 0; j < num_owners; j++) {
lldb::BreakpointLocationSP bp_loc_sp = site_locations.GetByIndex(j);
StreamString loc_desc;
if (log) {
bp_loc_sp->GetDescription(&loc_desc, eDescriptionLevelBrief);
}
// If another action disabled this breakpoint or its location, then
// don't run the actions.
if (!bp_loc_sp->IsEnabled() ||
!bp_loc_sp->GetBreakpoint().IsEnabled())
continue;
// The breakpoint site may have many locations associated with it,
// not all of them valid for this thread. Skip the ones that
// aren't:
if (!bp_loc_sp->ValidForThisThread(*thread_sp)) {
if (log) {
LLDB_LOGF(log,
"Breakpoint %s hit on thread 0x%llx but it was not "
"for this thread, continuing.",
loc_desc.GetData(),
static_cast<unsigned long long>(thread_sp->GetID()));
}
continue;
}
internal_breakpoint = bp_loc_sp->GetBreakpoint().IsInternal();
// First run the precondition, but since the precondition is per
// breakpoint, only run it once per breakpoint.
std::pair<std::unordered_set<break_id_t>::iterator, bool> result =
precondition_breakpoints.insert(
bp_loc_sp->GetBreakpoint().GetID());
if (!result.second)
continue;
bool precondition_result =
bp_loc_sp->GetBreakpoint().EvaluatePrecondition(context);
if (!precondition_result) {
actually_said_continue = true;
continue;
}
// Next run the condition for the breakpoint. If that says we
// should stop, then we'll run the callback for the breakpoint. If
// the callback says we shouldn't stop that will win.
if (bp_loc_sp->GetConditionText() != nullptr) {
Status condition_error;
bool condition_says_stop =
bp_loc_sp->ConditionSaysStop(exe_ctx, condition_error);
if (!condition_error.Success()) {
Debugger &debugger = exe_ctx.GetTargetRef().GetDebugger();
StreamSP error_sp = debugger.GetAsyncErrorStream();
error_sp->Printf("Stopped due to an error evaluating condition "
"of breakpoint ");
bp_loc_sp->GetDescription(error_sp.get(),
eDescriptionLevelBrief);
error_sp->Printf(": \"%s\"", bp_loc_sp->GetConditionText());
error_sp->EOL();
const char *err_str =
condition_error.AsCString("<Unknown Error>");
LLDB_LOGF(log, "Error evaluating condition: \"%s\"\n", err_str);
error_sp->PutCString(err_str);
error_sp->EOL();
error_sp->Flush();
} else {
LLDB_LOGF(log,
"Condition evaluated for breakpoint %s on thread "
"0x%llx condition_says_stop: %i.",
loc_desc.GetData(),
static_cast<unsigned long long>(thread_sp->GetID()),
condition_says_stop);
if (!condition_says_stop) {
// We don't want to increment the hit count of breakpoints if
// the condition fails. We've already bumped it by the time
// we get here, so undo the bump:
bp_loc_sp->UndoBumpHitCount();
actually_said_continue = true;
continue;
}
}
}
// We've done all the checks whose failure means "we consider lldb
// not to have hit the breakpoint". Now we're going to check for
// conditions that might continue after hitting. Start with the
// ignore count:
if (!bp_loc_sp->IgnoreCountShouldStop()) {
actually_said_continue = true;
continue;
}
// Check the auto-continue bit on the location, do this before the
// callback since it may change this, but that would be for the
// NEXT hit. Note, you might think you could check auto-continue
// before the condition, and not evaluate the condition if it says
// to continue. But failing the condition means the breakpoint was
// effectively NOT HIT. So these two states are different.
bool auto_continue_says_stop = true;
if (bp_loc_sp->IsAutoContinue())
{
LLDB_LOGF(log,
"Continuing breakpoint %s as AutoContinue was set.",
loc_desc.GetData());
// We want this stop reported, so you will know we auto-continued
// but only for external breakpoints:
if (!internal_breakpoint)
thread_sp->SetShouldReportStop(eVoteYes);
auto_continue_says_stop = false;
}
bool callback_says_stop = true;
// FIXME: For now the callbacks have to run in async mode - the
// first time we restart we need
// to get out of there. So set it here.
// When we figure out how to nest breakpoint hits then this will
// change.
// Don't run async callbacks in PerformAction. They have already
// been taken into account with async_should_stop.
if (!bp_loc_sp->IsCallbackSynchronous()) {
Debugger &debugger = thread_sp->CalculateTarget()->GetDebugger();
bool old_async = debugger.GetAsyncExecution();
debugger.SetAsyncExecution(true);
callback_says_stop = bp_loc_sp->InvokeCallback(&context);
debugger.SetAsyncExecution(old_async);
if (callback_says_stop && auto_continue_says_stop)
m_should_stop = true;
else
actually_said_continue = true;
}
// If we are going to stop for this breakpoint, then remove the
// breakpoint.
if (callback_says_stop && bp_loc_sp &&
bp_loc_sp->GetBreakpoint().IsOneShot()) {
thread_sp->GetProcess()->GetTarget().RemoveBreakpointByID(
bp_loc_sp->GetBreakpoint().GetID());
}
// Also make sure that the callback hasn't continued the target. If
// it did, when we'll set m_should_start to false and get out of
// here.
if (HasTargetRunSinceMe()) {
m_should_stop = false;
actually_said_continue = true;
break;
}
}
// At this point if nobody actually told us to continue, we should
// give the async breakpoint callback a chance to weigh in:
if (!actually_said_continue && !m_should_stop) {
m_should_stop = async_should_stop;
}
}
// We've figured out what this stop wants to do, so mark it as valid so
// we don't compute it again.
m_should_stop_is_valid = true;
} else {
m_should_stop = true;
m_should_stop_is_valid = true;
Log *log_process(
lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
LLDB_LOGF(log_process,
"Process::%s could not find breakpoint site id: %" PRId64
"...",
__FUNCTION__, m_value);
}
if ((!m_should_stop || internal_breakpoint) &&
thread_sp->CompletedPlanOverridesBreakpoint()) {
// Override should_stop decision when we have completed step plan
// additionally to the breakpoint
m_should_stop = true;
// We know we're stopping for a completed plan and we don't want to
// show the breakpoint stop, so compute the public stop info immediately
// here.
thread_sp->CalculatePublicStopInfo();
}
LLDB_LOGF(log,
"Process::%s returning from action with m_should_stop: %d.",
__FUNCTION__, m_should_stop);
}
}
private:
bool m_should_stop;
bool m_should_stop_is_valid;
bool m_should_perform_action; // Since we are trying to preserve the "state"
// of the system even if we run functions
// etc. behind the users backs, we need to make sure we only REALLY perform
// the action once.
lldb::addr_t m_address; // We use this to capture the breakpoint site address
// when we create the StopInfo,
// in case somebody deletes it between the time the StopInfo is made and the
// description is asked for.
lldb::break_id_t m_break_id;
bool m_was_one_shot;
};
// StopInfoWatchpoint
class StopInfoWatchpoint : public StopInfo {
public:
// Make sure watchpoint is properly disabled and subsequently enabled while
// performing watchpoint actions.
class WatchpointSentry {
public:
WatchpointSentry(ProcessSP p_sp, WatchpointSP w_sp) : process_sp(p_sp),
watchpoint_sp(w_sp) {
if (process_sp && watchpoint_sp) {
const bool notify = false;
watchpoint_sp->TurnOnEphemeralMode();
process_sp->DisableWatchpoint(watchpoint_sp.get(), notify);
process_sp->AddPreResumeAction(SentryPreResumeAction, this);
}
}
void DoReenable() {
if (process_sp && watchpoint_sp) {
bool was_disabled = watchpoint_sp->IsDisabledDuringEphemeralMode();
watchpoint_sp->TurnOffEphemeralMode();
const bool notify = false;
if (was_disabled) {
process_sp->DisableWatchpoint(watchpoint_sp.get(), notify);
} else {
process_sp->EnableWatchpoint(watchpoint_sp.get(), notify);
}
}
}
~WatchpointSentry() {
DoReenable();
if (process_sp)
process_sp->ClearPreResumeAction(SentryPreResumeAction, this);
}
static bool SentryPreResumeAction(void *sentry_void) {
WatchpointSentry *sentry = (WatchpointSentry *) sentry_void;
sentry->DoReenable();
return true;
}
private:
ProcessSP process_sp;
WatchpointSP watchpoint_sp;
};
StopInfoWatchpoint(Thread &thread, break_id_t watch_id,
lldb::addr_t watch_hit_addr)
: StopInfo(thread, watch_id), m_should_stop(false),
m_should_stop_is_valid(false), m_watch_hit_addr(watch_hit_addr) {}
~StopInfoWatchpoint() override = default;
StopReason GetStopReason() const override { return eStopReasonWatchpoint; }
const char *GetDescription() override {
if (m_description.empty()) {
StreamString strm;
strm.Printf("watchpoint %" PRIi64, m_value);
m_description = std::string(strm.GetString());
}
return m_description.c_str();
}
protected:
bool ShouldStopSynchronous(Event *event_ptr) override {
// ShouldStop() method is idempotent and should not affect hit count. See
// Process::RunPrivateStateThread()->Process()->HandlePrivateEvent()
// -->Process()::ShouldBroadcastEvent()->ThreadList::ShouldStop()->
// Thread::ShouldStop()->ThreadPlanBase::ShouldStop()->
// StopInfoWatchpoint::ShouldStop() and
// Event::DoOnRemoval()->Process::ProcessEventData::DoOnRemoval()->
// StopInfoWatchpoint::PerformAction().
if (m_should_stop_is_valid)
return m_should_stop;
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
WatchpointSP wp_sp(
thread_sp->CalculateTarget()->GetWatchpointList().FindByID(
GetValue()));
if (wp_sp) {
// Check if we should stop at a watchpoint.
ExecutionContext exe_ctx(thread_sp->GetStackFrameAtIndex(0));
StoppointCallbackContext context(event_ptr, exe_ctx, true);
m_should_stop = wp_sp->ShouldStop(&context);
} else {
Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
LLDB_LOGF(log,
"Process::%s could not find watchpoint location id: %" PRId64
"...",
__FUNCTION__, GetValue());
m_should_stop = true;
}
}
m_should_stop_is_valid = true;
return m_should_stop;
}
bool ShouldStop(Event *event_ptr) override {
// This just reports the work done by PerformAction or the synchronous
// stop. It should only ever get called after they have had a chance to
// run.
assert(m_should_stop_is_valid);
return m_should_stop;
}
void PerformAction(Event *event_ptr) override {
Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_WATCHPOINTS);
// We're going to calculate if we should stop or not in some way during the
// course of this code. Also by default we're going to stop, so set that
// here.
m_should_stop = true;
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
WatchpointSP wp_sp(
thread_sp->CalculateTarget()->GetWatchpointList().FindByID(
GetValue()));
if (wp_sp) {
ExecutionContext exe_ctx(thread_sp->GetStackFrameAtIndex(0));
ProcessSP process_sp = exe_ctx.GetProcessSP();
{
// check if this process is running on an architecture where
// watchpoints trigger before the associated instruction runs. if so,
// disable the WP, single-step and then re-enable the watchpoint
if (process_sp) {
uint32_t num;
bool wp_triggers_after;
if (process_sp->GetWatchpointSupportInfo(num, wp_triggers_after)
.Success()) {
if (!wp_triggers_after) {
// We need to preserve the watch_index before watchpoint is
// disable. Since Watchpoint::SetEnabled will clear the watch
// index. This will fix TestWatchpointIter failure
Watchpoint *wp = wp_sp.get();
uint32_t watch_index = wp->GetHardwareIndex();
process_sp->DisableWatchpoint(wp, false);
StopInfoSP stored_stop_info_sp = thread_sp->GetStopInfo();
assert(stored_stop_info_sp.get() == this);
Status new_plan_status;
ThreadPlanSP new_plan_sp(
thread_sp->QueueThreadPlanForStepSingleInstruction(
false, // step-over
false, // abort_other_plans
true, // stop_other_threads
new_plan_status));
if (new_plan_sp && new_plan_status.Success()) {
new_plan_sp->SetIsControllingPlan(true);
new_plan_sp->SetOkayToDiscard(false);
new_plan_sp->SetPrivate(true);
}
process_sp->GetThreadList().SetSelectedThreadByID(
thread_sp->GetID());
process_sp->ResumeSynchronous(nullptr);
process_sp->GetThreadList().SetSelectedThreadByID(
thread_sp->GetID());
thread_sp->SetStopInfo(stored_stop_info_sp);
process_sp->EnableWatchpoint(wp, false);
wp->SetHardwareIndex(watch_index);
}
}
}
}
// This sentry object makes sure the current watchpoint is disabled
// while performing watchpoint actions, and it is then enabled after we
// are finished.
WatchpointSentry sentry(process_sp, wp_sp);
/*
* MIPS: Last 3bits of the watchpoint address are masked by the kernel.
* For example:
* 'n' is at 0x120010d00 and 'm' is 0x120010d04. When a watchpoint is
* set at 'm', then
* watch exception is generated even when 'n' is read/written. To handle
* this case,
* server emulates the instruction at PC and finds the base address of
* the load/store
* instruction and appends it in the description of the stop-info
* packet. If watchpoint
* is not set on this address by user then this do not stop.
*/
if (m_watch_hit_addr != LLDB_INVALID_ADDRESS) {
WatchpointSP wp_hit_sp =
thread_sp->CalculateTarget()->GetWatchpointList().FindByAddress(
m_watch_hit_addr);
if (!wp_hit_sp) {
m_should_stop = false;
wp_sp->IncrementFalseAlarmsAndReviseHitCount();
}
}
// TODO: This condition should be checked in the synchronous part of the
// watchpoint code
// (Watchpoint::ShouldStop), so that we avoid pulling an event even if
// the watchpoint fails the ignore count condition. It is moved here
// temporarily, because for archs with
// watchpoint_exceptions_received=before, the code in the previous
// lines takes care of moving the inferior to next PC. We have to check
// the ignore count condition after this is done, otherwise we will hit
// same watchpoint multiple times until we pass ignore condition, but
// we won't actually be ignoring them.
if (wp_sp->GetHitCount() <= wp_sp->GetIgnoreCount())
m_should_stop = false;
Debugger &debugger = exe_ctx.GetTargetRef().GetDebugger();
if (m_should_stop && wp_sp->GetConditionText() != nullptr) {
// We need to make sure the user sees any parse errors in their
// condition, so we'll hook the constructor errors up to the
// debugger's Async I/O.
ExpressionResults result_code;
EvaluateExpressionOptions expr_options;
expr_options.SetUnwindOnError(true);
expr_options.SetIgnoreBreakpoints(true);
ValueObjectSP result_value_sp;
Status error;
result_code = UserExpression::Evaluate(
exe_ctx, expr_options, wp_sp->GetConditionText(),
llvm::StringRef(), result_value_sp, error);
if (result_code == eExpressionCompleted) {
if (result_value_sp) {
Scalar scalar_value;
if (result_value_sp->ResolveValue(scalar_value)) {
if (scalar_value.ULongLong(1) == 0) {
// We have been vetoed. This takes precedence over querying
// the watchpoint whether it should stop (aka ignore count
// and friends). See also StopInfoWatchpoint::ShouldStop()
// as well as Process::ProcessEventData::DoOnRemoval().
m_should_stop = false;
} else
m_should_stop = true;
LLDB_LOGF(log,
"Condition successfully evaluated, result is %s.\n",
m_should_stop ? "true" : "false");
} else {
m_should_stop = true;
LLDB_LOGF(
log,
"Failed to get an integer result from the expression.");
}
}
} else {
StreamSP error_sp = debugger.GetAsyncErrorStream();
error_sp->Printf(
"Stopped due to an error evaluating condition of watchpoint ");
wp_sp->GetDescription(error_sp.get(), eDescriptionLevelBrief);
error_sp->Printf(": \"%s\"", wp_sp->GetConditionText());
error_sp->EOL();
const char *err_str = error.AsCString("<Unknown Error>");
LLDB_LOGF(log, "Error evaluating condition: \"%s\"\n", err_str);
error_sp->PutCString(err_str);
error_sp->EOL();
error_sp->Flush();
// If the condition fails to be parsed or run, we should stop.
m_should_stop = true;
}
}
// If the condition says to stop, we run the callback to further decide
// whether to stop.
if (m_should_stop) {
// FIXME: For now the callbacks have to run in async mode - the
// first time we restart we need
// to get out of there. So set it here.
// When we figure out how to nest watchpoint hits then this will
// change.
bool old_async = debugger.GetAsyncExecution();
debugger.SetAsyncExecution(true);
StoppointCallbackContext context(event_ptr, exe_ctx, false);
bool stop_requested = wp_sp->InvokeCallback(&context);
debugger.SetAsyncExecution(old_async);
// Also make sure that the callback hasn't continued the target. If
// it did, when we'll set m_should_stop to false and get out of here.
if (HasTargetRunSinceMe())
m_should_stop = false;
if (m_should_stop && !stop_requested) {
// We have been vetoed by the callback mechanism.
m_should_stop = false;
}
}
// Finally, if we are going to stop, print out the new & old values:
if (m_should_stop) {
wp_sp->CaptureWatchedValue(exe_ctx);
Debugger &debugger = exe_ctx.GetTargetRef().GetDebugger();
StreamSP output_sp = debugger.GetAsyncOutputStream();
wp_sp->DumpSnapshots(output_sp.get());
output_sp->EOL();
output_sp->Flush();
}
} else {
Log *log_process(
lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
LLDB_LOGF(log_process,
"Process::%s could not find watchpoint id: %" PRId64 "...",
__FUNCTION__, m_value);
}
LLDB_LOGF(log,
"Process::%s returning from action with m_should_stop: %d.",
__FUNCTION__, m_should_stop);
m_should_stop_is_valid = true;
}
}
private:
bool m_should_stop;
bool m_should_stop_is_valid;
lldb::addr_t m_watch_hit_addr;
};
// StopInfoUnixSignal
class StopInfoUnixSignal : public StopInfo {
public:
StopInfoUnixSignal(Thread &thread, int signo, const char *description)
: StopInfo(thread, signo) {
SetDescription(description);
}
~StopInfoUnixSignal() override = default;
StopReason GetStopReason() const override { return eStopReasonSignal; }
bool ShouldStopSynchronous(Event *event_ptr) override {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
return thread_sp->GetProcess()->GetUnixSignals()->GetShouldStop(m_value);
return false;
}
bool ShouldStop(Event *event_ptr) override {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
return thread_sp->GetProcess()->GetUnixSignals()->GetShouldStop(m_value);
return false;
}
// If should stop returns false, check if we should notify of this event
bool DoShouldNotify(Event *event_ptr) override {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
bool should_notify =
thread_sp->GetProcess()->GetUnixSignals()->GetShouldNotify(m_value);
if (should_notify) {
StreamString strm;
strm.Printf(
"thread %d received signal: %s", thread_sp->GetIndexID(),
thread_sp->GetProcess()->GetUnixSignals()->GetSignalAsCString(
m_value));
Process::ProcessEventData::AddRestartedReason(event_ptr,
strm.GetData());
}
return should_notify;
}
return true;
}
void WillResume(lldb::StateType resume_state) override {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
if (!thread_sp->GetProcess()->GetUnixSignals()->GetShouldSuppress(
m_value))
thread_sp->SetResumeSignal(m_value);
}
}
const char *GetDescription() override {
if (m_description.empty()) {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp) {
StreamString strm;
const char *signal_name =
thread_sp->GetProcess()->GetUnixSignals()->GetSignalAsCString(
m_value);
if (signal_name)
strm.Printf("signal %s", signal_name);
else
strm.Printf("signal %" PRIi64, m_value);
m_description = std::string(strm.GetString());
}
}
return m_description.c_str();
}
};
// StopInfoTrace
class StopInfoTrace : public StopInfo {
public:
StopInfoTrace(Thread &thread) : StopInfo(thread, LLDB_INVALID_UID) {}
~StopInfoTrace() override = default;
StopReason GetStopReason() const override { return eStopReasonTrace; }
const char *GetDescription() override {
if (m_description.empty())
return "trace";
else
return m_description.c_str();
}
};
// StopInfoException
class StopInfoException : public StopInfo {
public:
StopInfoException(Thread &thread, const char *description)
: StopInfo(thread, LLDB_INVALID_UID) {
if (description)
SetDescription(description);
}
~StopInfoException() override = default;
StopReason GetStopReason() const override { return eStopReasonException; }
const char *GetDescription() override {
if (m_description.empty())
return "exception";
else
return m_description.c_str();
}
};
// StopInfoProcessorTrace
class StopInfoProcessorTrace : public StopInfo {
public:
StopInfoProcessorTrace(Thread &thread, const char *description)
: StopInfo(thread, LLDB_INVALID_UID) {
if (description)
SetDescription(description);
}
~StopInfoProcessorTrace() override = default;
StopReason GetStopReason() const override {
return eStopReasonProcessorTrace;
}
const char *GetDescription() override {
if (m_description.empty())
return "processor trace event";
else
return m_description.c_str();
}
};
// StopInfoThreadPlan
class StopInfoThreadPlan : public StopInfo {
public:
StopInfoThreadPlan(ThreadPlanSP &plan_sp, ValueObjectSP &return_valobj_sp,
ExpressionVariableSP &expression_variable_sp)
: StopInfo(plan_sp->GetThread(), LLDB_INVALID_UID), m_plan_sp(plan_sp),
m_return_valobj_sp(return_valobj_sp),
m_expression_variable_sp(expression_variable_sp) {}
~StopInfoThreadPlan() override = default;
StopReason GetStopReason() const override { return eStopReasonPlanComplete; }
const char *GetDescription() override {
if (m_description.empty()) {
StreamString strm;
m_plan_sp->GetDescription(&strm, eDescriptionLevelBrief);
m_description = std::string(strm.GetString());
}
return m_description.c_str();
}
ValueObjectSP GetReturnValueObject() { return m_return_valobj_sp; }
ExpressionVariableSP GetExpressionVariable() {
return m_expression_variable_sp;
}
protected:
bool ShouldStop(Event *event_ptr) override {
if (m_plan_sp)
return m_plan_sp->ShouldStop(event_ptr);
else
return StopInfo::ShouldStop(event_ptr);
}
private:
ThreadPlanSP m_plan_sp;
ValueObjectSP m_return_valobj_sp;
ExpressionVariableSP m_expression_variable_sp;
};
// StopInfoExec
class StopInfoExec : public StopInfo {
public:
StopInfoExec(Thread &thread)
: StopInfo(thread, LLDB_INVALID_UID), m_performed_action(false) {}
~StopInfoExec() override = default;
bool ShouldStop(Event *event_ptr) override {
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
return thread_sp->GetProcess()->GetStopOnExec();
return false;
}
StopReason GetStopReason() const override { return eStopReasonExec; }
const char *GetDescription() override { return "exec"; }
protected:
void PerformAction(Event *event_ptr) override {
// Only perform the action once
if (m_performed_action)
return;
m_performed_action = true;
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
thread_sp->GetProcess()->DidExec();
}
bool m_performed_action;
};
// StopInfoFork
class StopInfoFork : public StopInfo {
public:
StopInfoFork(Thread &thread, lldb::pid_t child_pid, lldb::tid_t child_tid)
: StopInfo(thread, child_pid), m_performed_action(false),
m_child_pid(child_pid), m_child_tid(child_tid) {}
~StopInfoFork() override = default;
bool ShouldStop(Event *event_ptr) override { return false; }
StopReason GetStopReason() const override { return eStopReasonFork; }
const char *GetDescription() override { return "fork"; }
protected:
void PerformAction(Event *event_ptr) override {
// Only perform the action once
if (m_performed_action)
return;
m_performed_action = true;
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
thread_sp->GetProcess()->DidFork(m_child_pid, m_child_tid);
}
bool m_performed_action;
private:
lldb::pid_t m_child_pid;
lldb::tid_t m_child_tid;
};
// StopInfoVFork
class StopInfoVFork : public StopInfo {
public:
StopInfoVFork(Thread &thread, lldb::pid_t child_pid, lldb::tid_t child_tid)
: StopInfo(thread, child_pid), m_performed_action(false),
m_child_pid(child_pid), m_child_tid(child_tid) {}
~StopInfoVFork() override = default;
bool ShouldStop(Event *event_ptr) override { return false; }
StopReason GetStopReason() const override { return eStopReasonVFork; }
const char *GetDescription() override { return "vfork"; }
protected:
void PerformAction(Event *event_ptr) override {
// Only perform the action once
if (m_performed_action)
return;
m_performed_action = true;
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
thread_sp->GetProcess()->DidVFork(m_child_pid, m_child_tid);
}
bool m_performed_action;
private:
lldb::pid_t m_child_pid;
lldb::tid_t m_child_tid;
};
// StopInfoVForkDone
class StopInfoVForkDone : public StopInfo {
public:
StopInfoVForkDone(Thread &thread)
: StopInfo(thread, 0), m_performed_action(false) {}
~StopInfoVForkDone() override = default;
bool ShouldStop(Event *event_ptr) override { return false; }
StopReason GetStopReason() const override { return eStopReasonVForkDone; }
const char *GetDescription() override { return "vforkdone"; }
protected:
void PerformAction(Event *event_ptr) override {
// Only perform the action once
if (m_performed_action)
return;
m_performed_action = true;
ThreadSP thread_sp(m_thread_wp.lock());
if (thread_sp)
thread_sp->GetProcess()->DidVForkDone();
}
bool m_performed_action;
};
} // namespace lldb_private
StopInfoSP StopInfo::CreateStopReasonWithBreakpointSiteID(Thread &thread,
break_id_t break_id) {
return StopInfoSP(new StopInfoBreakpoint(thread, break_id));
}
StopInfoSP StopInfo::CreateStopReasonWithBreakpointSiteID(Thread &thread,
break_id_t break_id,
bool should_stop) {
return StopInfoSP(new StopInfoBreakpoint(thread, break_id, should_stop));
}
StopInfoSP
StopInfo::CreateStopReasonWithWatchpointID(Thread &thread, break_id_t watch_id,
lldb::addr_t watch_hit_addr) {
return StopInfoSP(new StopInfoWatchpoint(thread, watch_id, watch_hit_addr));
}
StopInfoSP StopInfo::CreateStopReasonWithSignal(Thread &thread, int signo,
const char *description) {
thread.GetProcess()->GetUnixSignals()->IncrementSignalHitCount(signo);
return StopInfoSP(new StopInfoUnixSignal(thread, signo, description));
}
StopInfoSP StopInfo::CreateStopReasonToTrace(Thread &thread) {
return StopInfoSP(new StopInfoTrace(thread));
}
StopInfoSP StopInfo::CreateStopReasonWithPlan(
ThreadPlanSP &plan_sp, ValueObjectSP return_valobj_sp,
ExpressionVariableSP expression_variable_sp) {
return StopInfoSP(new StopInfoThreadPlan(plan_sp, return_valobj_sp,
expression_variable_sp));
}
StopInfoSP StopInfo::CreateStopReasonWithException(Thread &thread,
const char *description) {
return StopInfoSP(new StopInfoException(thread, description));
}
StopInfoSP StopInfo::CreateStopReasonProcessorTrace(Thread &thread,
const char *description) {
return StopInfoSP(new StopInfoProcessorTrace(thread, description));
}
StopInfoSP StopInfo::CreateStopReasonWithExec(Thread &thread) {
return StopInfoSP(new StopInfoExec(thread));
}
StopInfoSP StopInfo::CreateStopReasonFork(Thread &thread,
lldb::pid_t child_pid,
lldb::tid_t child_tid) {
return StopInfoSP(new StopInfoFork(thread, child_pid, child_tid));
}
StopInfoSP StopInfo::CreateStopReasonVFork(Thread &thread,
lldb::pid_t child_pid,
lldb::tid_t child_tid) {
return StopInfoSP(new StopInfoVFork(thread, child_pid, child_tid));
}
StopInfoSP StopInfo::CreateStopReasonVForkDone(Thread &thread) {
return StopInfoSP(new StopInfoVForkDone(thread));
}
ValueObjectSP StopInfo::GetReturnValueObject(StopInfoSP &stop_info_sp) {
if (stop_info_sp &&
stop_info_sp->GetStopReason() == eStopReasonPlanComplete) {
StopInfoThreadPlan *plan_stop_info =
static_cast<StopInfoThreadPlan *>(stop_info_sp.get());
return plan_stop_info->GetReturnValueObject();
} else
return ValueObjectSP();
}
ExpressionVariableSP StopInfo::GetExpressionVariable(StopInfoSP &stop_info_sp) {
if (stop_info_sp &&
stop_info_sp->GetStopReason() == eStopReasonPlanComplete) {
StopInfoThreadPlan *plan_stop_info =
static_cast<StopInfoThreadPlan *>(stop_info_sp.get());
return plan_stop_info->GetExpressionVariable();
} else
return ExpressionVariableSP();
}
lldb::ValueObjectSP
StopInfo::GetCrashingDereference(StopInfoSP &stop_info_sp,
lldb::addr_t *crashing_address) {
if (!stop_info_sp) {
return ValueObjectSP();
}
const char *description = stop_info_sp->GetDescription();
if (!description) {
return ValueObjectSP();
}
ThreadSP thread_sp = stop_info_sp->GetThread();
if (!thread_sp) {
return ValueObjectSP();
}
StackFrameSP frame_sp = thread_sp->GetSelectedFrame();
if (!frame_sp) {
return ValueObjectSP();
}
const char address_string[] = "address=";
const char *address_loc = strstr(description, address_string);
if (!address_loc) {
return ValueObjectSP();
}
address_loc += (sizeof(address_string) - 1);
uint64_t address = strtoull(address_loc, nullptr, 0);
if (crashing_address) {
*crashing_address = address;
}
return frame_sp->GuessValueForAddress(address);
}
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