You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

390 lines
13 KiB

//===-- Watchpoint.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/Breakpoint/Watchpoint.h"
#include "lldb/Breakpoint/StoppointCallbackContext.h"
#include "lldb/Core/Value.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectMemory.h"
#include "lldb/Expression/UserExpression.h"
#include "lldb/Symbol/TypeSystem.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/ThreadSpec.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Stream.h"
using namespace lldb;
using namespace lldb_private;
Watchpoint::Watchpoint(Target &target, lldb::addr_t addr, uint32_t size,
const CompilerType *type, bool hardware)
: StoppointSite(0, addr, size, hardware), m_target(target),
m_enabled(false), m_is_hardware(hardware), m_is_watch_variable(false),
m_is_ephemeral(false), m_disabled_count(0), m_watch_read(0),
m_watch_write(0), m_watch_was_read(0), m_watch_was_written(0),
m_ignore_count(0), m_false_alarms(0), m_decl_str(), m_watch_spec_str(),
m_type(), m_error(), m_options(), m_being_created(true) {
if (type && type->IsValid())
m_type = *type;
else {
// If we don't have a known type, then we force it to unsigned int of the
// right size.
auto type_system_or_err =
target.GetScratchTypeSystemForLanguage(eLanguageTypeC);
if (auto err = type_system_or_err.takeError()) {
LLDB_LOG_ERROR(
lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_WATCHPOINTS),
std::move(err), "Failed to set type.");
} else {
m_type = type_system_or_err->GetBuiltinTypeForEncodingAndBitSize(
eEncodingUint, 8 * size);
}
}
// Set the initial value of the watched variable:
if (m_target.GetProcessSP()) {
ExecutionContext exe_ctx;
m_target.GetProcessSP()->CalculateExecutionContext(exe_ctx);
CaptureWatchedValue(exe_ctx);
}
m_being_created = false;
}
Watchpoint::~Watchpoint() = default;
// This function is used when "baton" doesn't need to be freed
void Watchpoint::SetCallback(WatchpointHitCallback callback, void *baton,
bool is_synchronous) {
// The default "Baton" class will keep a copy of "baton" and won't free or
// delete it when it goes goes out of scope.
m_options.SetCallback(callback, std::make_shared<UntypedBaton>(baton),
is_synchronous);
SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
}
// This function is used when a baton needs to be freed and therefore is
// contained in a "Baton" subclass.
void Watchpoint::SetCallback(WatchpointHitCallback callback,
const BatonSP &callback_baton_sp,
bool is_synchronous) {
m_options.SetCallback(callback, callback_baton_sp, is_synchronous);
SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
}
void Watchpoint::ClearCallback() {
m_options.ClearCallback();
SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
}
void Watchpoint::SetDeclInfo(const std::string &str) { m_decl_str = str; }
std::string Watchpoint::GetWatchSpec() { return m_watch_spec_str; }
void Watchpoint::SetWatchSpec(const std::string &str) {
m_watch_spec_str = str;
}
bool Watchpoint::IsHardware() const {
lldbassert(m_is_hardware || !HardwareRequired());
return m_is_hardware;
}
bool Watchpoint::IsWatchVariable() const { return m_is_watch_variable; }
void Watchpoint::SetWatchVariable(bool val) { m_is_watch_variable = val; }
bool Watchpoint::CaptureWatchedValue(const ExecutionContext &exe_ctx) {
ConstString watch_name("$__lldb__watch_value");
m_old_value_sp = m_new_value_sp;
Address watch_address(GetLoadAddress());
if (!m_type.IsValid()) {
// Don't know how to report new & old values, since we couldn't make a
// scalar type for this watchpoint. This works around an assert in
// ValueObjectMemory::Create.
// FIXME: This should not happen, but if it does in some case we care about,
// we can go grab the value raw and print it as unsigned.
return false;
}
m_new_value_sp = ValueObjectMemory::Create(
exe_ctx.GetBestExecutionContextScope(), watch_name.GetStringRef(),
watch_address, m_type);
m_new_value_sp = m_new_value_sp->CreateConstantValue(watch_name);
return (m_new_value_sp && m_new_value_sp->GetError().Success());
}
void Watchpoint::IncrementFalseAlarmsAndReviseHitCount() {
++m_false_alarms;
if (m_false_alarms) {
if (m_hit_counter.GetValue() >= m_false_alarms) {
m_hit_counter.Decrement(m_false_alarms);
m_false_alarms = 0;
} else {
m_false_alarms -= m_hit_counter.GetValue();
m_hit_counter.Reset();
}
}
}
// RETURNS - true if we should stop at this breakpoint, false if we
// should continue.
bool Watchpoint::ShouldStop(StoppointCallbackContext *context) {
m_hit_counter.Increment();
return IsEnabled();
}
void Watchpoint::GetDescription(Stream *s, lldb::DescriptionLevel level) {
DumpWithLevel(s, level);
}
void Watchpoint::Dump(Stream *s) const {
DumpWithLevel(s, lldb::eDescriptionLevelBrief);
}
// If prefix is nullptr, we display the watch id and ignore the prefix
// altogether.
void Watchpoint::DumpSnapshots(Stream *s, const char *prefix) const {
if (!prefix) {
s->Printf("\nWatchpoint %u hit:", GetID());
prefix = "";
}
if (m_old_value_sp) {
const char *old_value_cstr = m_old_value_sp->GetValueAsCString();
if (old_value_cstr && old_value_cstr[0])
s->Printf("\n%sold value: %s", prefix, old_value_cstr);
else {
const char *old_summary_cstr = m_old_value_sp->GetSummaryAsCString();
if (old_summary_cstr && old_summary_cstr[0])
s->Printf("\n%sold value: %s", prefix, old_summary_cstr);
}
}
if (m_new_value_sp) {
const char *new_value_cstr = m_new_value_sp->GetValueAsCString();
if (new_value_cstr && new_value_cstr[0])
s->Printf("\n%snew value: %s", prefix, new_value_cstr);
else {
const char *new_summary_cstr = m_new_value_sp->GetSummaryAsCString();
if (new_summary_cstr && new_summary_cstr[0])
s->Printf("\n%snew value: %s", prefix, new_summary_cstr);
}
}
}
void Watchpoint::DumpWithLevel(Stream *s,
lldb::DescriptionLevel description_level) const {
if (s == nullptr)
return;
assert(description_level >= lldb::eDescriptionLevelBrief &&
description_level <= lldb::eDescriptionLevelVerbose);
s->Printf("Watchpoint %u: addr = 0x%8.8" PRIx64
" size = %u state = %s type = %s%s",
GetID(), GetLoadAddress(), m_byte_size,
IsEnabled() ? "enabled" : "disabled", m_watch_read ? "r" : "",
m_watch_write ? "w" : "");
if (description_level >= lldb::eDescriptionLevelFull) {
if (!m_decl_str.empty())
s->Printf("\n declare @ '%s'", m_decl_str.c_str());
if (!m_watch_spec_str.empty())
s->Printf("\n watchpoint spec = '%s'", m_watch_spec_str.c_str());
// Dump the snapshots we have taken.
DumpSnapshots(s, " ");
if (GetConditionText())
s->Printf("\n condition = '%s'", GetConditionText());
m_options.GetCallbackDescription(s, description_level);
}
if (description_level >= lldb::eDescriptionLevelVerbose) {
s->Printf("\n hw_index = %i hit_count = %-4u ignore_count = %-4u",
GetHardwareIndex(), GetHitCount(), GetIgnoreCount());
}
}
bool Watchpoint::IsEnabled() const { return m_enabled; }
// Within StopInfo.cpp, we purposely turn on the ephemeral mode right before
// temporarily disable the watchpoint in order to perform possible watchpoint
// actions without triggering further watchpoint events. After the temporary
// disabled watchpoint is enabled, we then turn off the ephemeral mode.
void Watchpoint::TurnOnEphemeralMode() { m_is_ephemeral = true; }
void Watchpoint::TurnOffEphemeralMode() {
m_is_ephemeral = false;
// Leaving ephemeral mode, reset the m_disabled_count!
m_disabled_count = 0;
}
bool Watchpoint::IsDisabledDuringEphemeralMode() {
return m_disabled_count > 1 && m_is_ephemeral;
}
void Watchpoint::SetEnabled(bool enabled, bool notify) {
if (!enabled) {
if (!m_is_ephemeral)
SetHardwareIndex(LLDB_INVALID_INDEX32);
else
++m_disabled_count;
// Don't clear the snapshots for now.
// Within StopInfo.cpp, we purposely do disable/enable watchpoint while
// performing watchpoint actions.
}
bool changed = enabled != m_enabled;
m_enabled = enabled;
if (notify && !m_is_ephemeral && changed)
SendWatchpointChangedEvent(enabled ? eWatchpointEventTypeEnabled
: eWatchpointEventTypeDisabled);
}
void Watchpoint::SetWatchpointType(uint32_t type, bool notify) {
int old_watch_read = m_watch_read;
int old_watch_write = m_watch_write;
m_watch_read = (type & LLDB_WATCH_TYPE_READ) != 0;
m_watch_write = (type & LLDB_WATCH_TYPE_WRITE) != 0;
if (notify &&
(old_watch_read != m_watch_read || old_watch_write != m_watch_write))
SendWatchpointChangedEvent(eWatchpointEventTypeTypeChanged);
}
bool Watchpoint::WatchpointRead() const { return m_watch_read != 0; }
bool Watchpoint::WatchpointWrite() const { return m_watch_write != 0; }
uint32_t Watchpoint::GetIgnoreCount() const { return m_ignore_count; }
void Watchpoint::SetIgnoreCount(uint32_t n) {
bool changed = m_ignore_count != n;
m_ignore_count = n;
if (changed)
SendWatchpointChangedEvent(eWatchpointEventTypeIgnoreChanged);
}
bool Watchpoint::InvokeCallback(StoppointCallbackContext *context) {
return m_options.InvokeCallback(context, GetID());
}
void Watchpoint::SetCondition(const char *condition) {
if (condition == nullptr || condition[0] == '\0') {
if (m_condition_up)
m_condition_up.reset();
} else {
// Pass nullptr for expr_prefix (no translation-unit level definitions).
Status error;
m_condition_up.reset(m_target.GetUserExpressionForLanguage(
condition, llvm::StringRef(), lldb::eLanguageTypeUnknown,
UserExpression::eResultTypeAny, EvaluateExpressionOptions(), nullptr,
error));
if (error.Fail()) {
// FIXME: Log something...
m_condition_up.reset();
}
}
SendWatchpointChangedEvent(eWatchpointEventTypeConditionChanged);
}
const char *Watchpoint::GetConditionText() const {
if (m_condition_up)
return m_condition_up->GetUserText();
else
return nullptr;
}
void Watchpoint::SendWatchpointChangedEvent(
lldb::WatchpointEventType eventKind) {
if (!m_being_created &&
GetTarget().EventTypeHasListeners(
Target::eBroadcastBitWatchpointChanged)) {
WatchpointEventData *data =
new Watchpoint::WatchpointEventData(eventKind, shared_from_this());
GetTarget().BroadcastEvent(Target::eBroadcastBitWatchpointChanged, data);
}
}
void Watchpoint::SendWatchpointChangedEvent(WatchpointEventData *data) {
if (data == nullptr)
return;
if (!m_being_created &&
GetTarget().EventTypeHasListeners(Target::eBroadcastBitWatchpointChanged))
GetTarget().BroadcastEvent(Target::eBroadcastBitWatchpointChanged, data);
else
delete data;
}
Watchpoint::WatchpointEventData::WatchpointEventData(
WatchpointEventType sub_type, const WatchpointSP &new_watchpoint_sp)
: EventData(), m_watchpoint_event(sub_type),
m_new_watchpoint_sp(new_watchpoint_sp) {}
Watchpoint::WatchpointEventData::~WatchpointEventData() = default;
ConstString Watchpoint::WatchpointEventData::GetFlavorString() {
static ConstString g_flavor("Watchpoint::WatchpointEventData");
return g_flavor;
}
ConstString Watchpoint::WatchpointEventData::GetFlavor() const {
return WatchpointEventData::GetFlavorString();
}
WatchpointSP &Watchpoint::WatchpointEventData::GetWatchpoint() {
return m_new_watchpoint_sp;
}
WatchpointEventType
Watchpoint::WatchpointEventData::GetWatchpointEventType() const {
return m_watchpoint_event;
}
void Watchpoint::WatchpointEventData::Dump(Stream *s) const {}
const Watchpoint::WatchpointEventData *
Watchpoint::WatchpointEventData::GetEventDataFromEvent(const Event *event) {
if (event) {
const EventData *event_data = event->GetData();
if (event_data &&
event_data->GetFlavor() == WatchpointEventData::GetFlavorString())
return static_cast<const WatchpointEventData *>(event->GetData());
}
return nullptr;
}
WatchpointEventType
Watchpoint::WatchpointEventData::GetWatchpointEventTypeFromEvent(
const EventSP &event_sp) {
const WatchpointEventData *data = GetEventDataFromEvent(event_sp.get());
if (data == nullptr)
return eWatchpointEventTypeInvalidType;
else
return data->GetWatchpointEventType();
}
WatchpointSP Watchpoint::WatchpointEventData::GetWatchpointFromEvent(
const EventSP &event_sp) {
WatchpointSP wp_sp;
const WatchpointEventData *data = GetEventDataFromEvent(event_sp.get());
if (data)
wp_sp = data->m_new_watchpoint_sp;
return wp_sp;
}