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//===-- 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/Breakpoint/WatchpointResource.h"
#include "lldb/Core/Value.h"
#include "lldb/DataFormatters/DumpValueObjectOptions.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/LLDBLog.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Stream.h"
#include "lldb/ValueObject/ValueObject.h"
#include "lldb/ValueObject/ValueObjectMemory.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_modify(0), m_ignore_count(0) {
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(GetLog(LLDBLog::Watchpoints), std::move(err),
"Failed to set type: {0}");
} else {
if (auto ts = *type_system_or_err) {
if (size <= target.GetArchitecture().GetAddressByteSize()) {
m_type =
ts->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint, 8 * size);
} else {
CompilerType clang_uint8_type =
ts->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint, 8);
m_type = clang_uint8_type.GetArrayType(size);
}
} else
LLDB_LOG_ERROR(GetLog(LLDBLog::Watchpoints), std::move(err),
"Failed to set type: Typesystem is no longer live: {0}");
}
}
// Set the initial value of the watched variable:
if (m_target.GetProcessSP()) {
ExecutionContext exe_ctx;
m_target.GetProcessSP()->CalculateExecutionContext(exe_ctx);
CaptureWatchedValue(exe_ctx);
}
}
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 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);
}
bool Watchpoint::SetupVariableWatchpointDisabler(StackFrameSP frame_sp) const {
if (!frame_sp)
return false;
ThreadSP thread_sp = frame_sp->GetThread();
if (!thread_sp)
return false;
uint32_t return_frame_index =
thread_sp->GetSelectedFrameIndex(DoNoSelectMostRelevantFrame) + 1;
if (return_frame_index >= LLDB_INVALID_FRAME_ID)
return false;
StackFrameSP return_frame_sp(
thread_sp->GetStackFrameAtIndex(return_frame_index));
if (!return_frame_sp)
return false;
ExecutionContext exe_ctx(return_frame_sp);
TargetSP target_sp = exe_ctx.GetTargetSP();
if (!target_sp)
return false;
Address return_address(return_frame_sp->GetFrameCodeAddress());
lldb::addr_t return_addr = return_address.GetLoadAddress(target_sp.get());
if (return_addr == LLDB_INVALID_ADDRESS)
return false;
BreakpointSP bp_sp = target_sp->CreateBreakpoint(
return_addr, /*internal=*/true, /*request_hardware=*/false);
if (!bp_sp || !bp_sp->HasResolvedLocations())
return false;
auto wvc_up = std::make_unique<WatchpointVariableContext>(GetID(), exe_ctx);
auto baton_sp = std::make_shared<WatchpointVariableBaton>(std::move(wvc_up));
bp_sp->SetCallback(VariableWatchpointDisabler, baton_sp);
bp_sp->SetOneShot(true);
bp_sp->SetBreakpointKind("variable watchpoint disabler");
return true;
}
bool Watchpoint::VariableWatchpointDisabler(void *baton,
StoppointCallbackContext *context,
user_id_t break_id,
user_id_t break_loc_id) {
assert(baton && "null baton");
if (!baton || !context)
return false;
Log *log = GetLog(LLDBLog::Watchpoints);
WatchpointVariableContext *wvc =
static_cast<WatchpointVariableContext *>(baton);
LLDB_LOGF(log, "called by breakpoint %" PRIu64 ".%" PRIu64, break_id,
break_loc_id);
if (wvc->watch_id == LLDB_INVALID_WATCH_ID)
return false;
TargetSP target_sp = context->exe_ctx_ref.GetTargetSP();
if (!target_sp)
return false;
ProcessSP process_sp = target_sp->GetProcessSP();
if (!process_sp)
return false;
WatchpointSP watch_sp =
target_sp->GetWatchpointList().FindByID(wvc->watch_id);
if (!watch_sp)
return false;
if (wvc->exe_ctx == context->exe_ctx_ref) {
LLDB_LOGF(log,
"callback for watchpoint %" PRId32
" matched internal breakpoint execution context",
watch_sp->GetID());
process_sp->DisableWatchpoint(watch_sp);
return false;
}
LLDB_LOGF(log,
"callback for watchpoint %" PRId32
" didn't match internal breakpoint execution context",
watch_sp->GetID());
return false;
}
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 g_watch_name("$__lldb__watch_value");
m_old_value_sp = m_new_value_sp;
Address watch_address(GetLoadAddress());
if (!m_type.IsValid()) {
// Don't know how to report new & old values, since we couldn't make a
// scalar type for this watchpoint. This works around an assert in
// ValueObjectMemory::Create.
// FIXME: This should not happen, but if it does in some case we care about,
// we can go grab the value raw and print it as unsigned.
return false;
}
m_new_value_sp = ValueObjectMemory::Create(
exe_ctx.GetBestExecutionContextScope(), g_watch_name.GetStringRef(),
watch_address, m_type);
m_new_value_sp = m_new_value_sp->CreateConstantValue(g_watch_name);
return (m_new_value_sp && m_new_value_sp->GetError().Success());
}
bool Watchpoint::WatchedValueReportable(const ExecutionContext &exe_ctx) {
if (!m_watch_modify || m_watch_read)
return true;
if (!m_type.IsValid())
return true;
ConstString g_watch_name("$__lldb__watch_value");
Address watch_address(GetLoadAddress());
ValueObjectSP newest_valueobj_sp = ValueObjectMemory::Create(
exe_ctx.GetBestExecutionContextScope(), g_watch_name.GetStringRef(),
watch_address, m_type);
newest_valueobj_sp = newest_valueobj_sp->CreateConstantValue(g_watch_name);
Status error;
DataExtractor new_data;
DataExtractor old_data;
newest_valueobj_sp->GetData(new_data, error);
if (error.Fail())
return true;
m_new_value_sp->GetData(old_data, error);
if (error.Fail())
return true;
if (new_data.GetByteSize() != old_data.GetByteSize() ||
new_data.GetByteSize() == 0)
return true;
if (memcmp(new_data.GetDataStart(), old_data.GetDataStart(),
old_data.GetByteSize()) == 0)
return false; // Value has not changed, user requested modify watchpoint
return true;
}
// 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.
bool Watchpoint::DumpSnapshots(Stream *s, const char *prefix) const {
bool printed_anything = false;
// For read watchpoints, don't display any before/after value changes.
if (m_watch_read && !m_watch_modify && !m_watch_write)
return printed_anything;
s->Printf("\n");
s->Printf("Watchpoint %u hit:\n", GetID());
StreamString values_ss;
if (prefix)
values_ss.Indent(prefix);
if (m_old_value_sp) {
if (auto *old_value_cstr = m_old_value_sp->GetValueAsCString()) {
values_ss.Printf("old value: %s", old_value_cstr);
} else {
if (auto *old_summary_cstr = m_old_value_sp->GetSummaryAsCString())
values_ss.Printf("old value: %s", old_summary_cstr);
else {
StreamString strm;
DumpValueObjectOptions options;
options.SetUseDynamicType(eNoDynamicValues)
.SetHideRootType(true)
.SetHideRootName(true)
.SetHideName(true);
if (llvm::Error error = m_old_value_sp->Dump(strm, options))
strm << "error: " << toString(std::move(error));
if (strm.GetData())
values_ss.Printf("old value: %s", strm.GetData());
}
}
}
if (m_new_value_sp) {
if (values_ss.GetSize())
values_ss.Printf("\n");
if (auto *new_value_cstr = m_new_value_sp->GetValueAsCString())
values_ss.Printf("new value: %s", new_value_cstr);
else {
if (auto *new_summary_cstr = m_new_value_sp->GetSummaryAsCString())
values_ss.Printf("new value: %s", new_summary_cstr);
else {
StreamString strm;
DumpValueObjectOptions options;
options.SetUseDynamicType(eNoDynamicValues)
.SetHideRootType(true)
.SetHideRootName(true)
.SetHideName(true);
if (llvm::Error error = m_new_value_sp->Dump(strm, options))
strm << "error: " << toString(std::move(error));
if (strm.GetData())
values_ss.Printf("new value: %s", strm.GetData());
}
}
}
if (values_ss.GetSize()) {
s->Printf("%s", values_ss.GetData());
printed_anything = true;
}
return printed_anything;
}
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%s",
GetID(), GetLoadAddress(), m_byte_size,
IsEnabled() ? "enabled" : "disabled", m_watch_read ? "r" : "",
m_watch_write ? "w" : "", m_watch_modify ? "m" : "");
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());
if (IsEnabled()) {
if (ProcessSP process_sp = m_target.GetProcessSP()) {
auto &resourcelist = process_sp->GetWatchpointResourceList();
size_t idx = 0;
s->Printf("\n watchpoint resources:");
for (WatchpointResourceSP &wpres : resourcelist.Sites()) {
if (wpres->ConstituentsContains(this)) {
s->Printf("\n #%zu: ", idx);
wpres->Dump(s);
}
idx++;
}
}
}
// 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 hit_count = %-4u ignore_count = %-4u", 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)
++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;
int old_watch_modify = m_watch_modify;
m_watch_read = (type & LLDB_WATCH_TYPE_READ) != 0;
m_watch_write = (type & LLDB_WATCH_TYPE_WRITE) != 0;
m_watch_modify = (type & LLDB_WATCH_TYPE_MODIFY) != 0;
if (notify &&
(old_watch_read != m_watch_read || old_watch_write != m_watch_write ||
old_watch_modify != m_watch_modify))
SendWatchpointChangedEvent(eWatchpointEventTypeTypeChanged);
}
bool Watchpoint::WatchpointRead() const { return m_watch_read != 0; }
bool Watchpoint::WatchpointWrite() const { return m_watch_write != 0; }
bool Watchpoint::WatchpointModify() const { return m_watch_modify != 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, {}, {}, 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();
return nullptr;
}
void Watchpoint::SendWatchpointChangedEvent(
lldb::WatchpointEventType eventKind) {
if (GetTarget().EventTypeHasListeners(
Target::eBroadcastBitWatchpointChanged)) {
auto data_sp =
std::make_shared<WatchpointEventData>(eventKind, shared_from_this());
GetTarget().BroadcastEvent(Target::eBroadcastBitWatchpointChanged, data_sp);
}
}
Watchpoint::WatchpointEventData::WatchpointEventData(
WatchpointEventType sub_type, const WatchpointSP &new_watchpoint_sp)
: m_watchpoint_event(sub_type), m_new_watchpoint_sp(new_watchpoint_sp) {}
Watchpoint::WatchpointEventData::~WatchpointEventData() = default;
llvm::StringRef Watchpoint::WatchpointEventData::GetFlavorString() {
return "Watchpoint::WatchpointEventData";
}
llvm::StringRef 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;
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;
}
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