contrib/llvm/tools/lldb/source/Breakpoint/Watchpoint.cpp

   1 //===-- Watchpoint.cpp ------------------------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 // C Includes
  11 // C++ Includes
  12 // Other libraries and framework includes
  13 // Project includes
  14 #include "lldb/Breakpoint/Watchpoint.h"
  15
  16 #include "lldb/Breakpoint/StoppointCallbackContext.h"
  17 #include "lldb/Core/Value.h"
  18 #include "lldb/Core/ValueObject.h"
  19 #include "lldb/Core/ValueObjectMemory.h"
  20 #include "lldb/Expression/UserExpression.h"
  21 #include "lldb/Symbol/ClangASTContext.h"
  22 #include "lldb/Target/Process.h"
  23 #include "lldb/Target/Target.h"
  24 #include "lldb/Target/ThreadSpec.h"
  25 #include "lldb/Utility/Stream.h"
  26
  27 using namespace lldb;
  28 using namespace lldb_private;
  29
  30 Watchpoint::Watchpoint(Target &target, lldb::addr_t addr, uint32_t size,
  31                        const CompilerType *type, bool hardware)
  32     : StoppointLocation(0, addr, size, hardware), m_target(target),
  33       m_enabled(false), m_is_hardware(hardware), m_is_watch_variable(false),
  34       m_is_ephemeral(false), m_disabled_count(0), m_watch_read(0),
  35       m_watch_write(0), m_watch_was_read(0), m_watch_was_written(0),
  36       m_ignore_count(0), m_false_alarms(0), m_decl_str(), m_watch_spec_str(),
  37       m_type(), m_error(), m_options(), m_being_created(true) {
  38   if (type && type->IsValid())
  39     m_type = *type;
  40   else {
  41     // If we don't have a known type, then we force it to unsigned int of the
  42     // right size.
  43     ClangASTContext *ast_context = target.GetScratchClangASTContext();
  44     m_type = ast_context->GetBuiltinTypeForEncodingAndBitSize(eEncodingUint,
  45                                                               8 * size);
  46   }
  47
  48   // Set the initial value of the watched variable:
  49   if (m_target.GetProcessSP()) {
  50     ExecutionContext exe_ctx;
  51     m_target.GetProcessSP()->CalculateExecutionContext(exe_ctx);
  52     CaptureWatchedValue(exe_ctx);
  53   }
  54   m_being_created = false;
  55 }
  56
  57 Watchpoint::~Watchpoint() = default;
  58
  59 // This function is used when "baton" doesn't need to be freed
  60 void Watchpoint::SetCallback(WatchpointHitCallback callback, void *baton,
  61                              bool is_synchronous) {
  62   // The default "Baton" class will keep a copy of "baton" and won't free
  63   // or delete it when it goes goes out of scope.
  64   m_options.SetCallback(callback, std::make_shared<UntypedBaton>(baton),
  65                         is_synchronous);
  66
  67   SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
  68 }
  69
  70 // This function is used when a baton needs to be freed and therefore is
  71 // contained in a "Baton" subclass.
  72 void Watchpoint::SetCallback(WatchpointHitCallback callback,
  73                              const BatonSP &callback_baton_sp,
  74                              bool is_synchronous) {
  75   m_options.SetCallback(callback, callback_baton_sp, is_synchronous);
  76   SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
  77 }
  78
  79 void Watchpoint::ClearCallback() {
  80   m_options.ClearCallback();
  81   SendWatchpointChangedEvent(eWatchpointEventTypeCommandChanged);
  82 }
  83
  84 void Watchpoint::SetDeclInfo(const std::string &str) { m_decl_str = str; }
  85
  86 std::string Watchpoint::GetWatchSpec() { return m_watch_spec_str; }
  87
  88 void Watchpoint::SetWatchSpec(const std::string &str) {
  89   m_watch_spec_str = str;
  90 }
  91
  92 // Override default impl of StoppointLocation::IsHardware() since m_is_hardware
  93 // member field is more accurate.
  94 bool Watchpoint::IsHardware() const { return m_is_hardware; }
  95
  96 bool Watchpoint::IsWatchVariable() const { return m_is_watch_variable; }
  97
  98 void Watchpoint::SetWatchVariable(bool val) { m_is_watch_variable = val; }
  99
 100 bool Watchpoint::CaptureWatchedValue(const ExecutionContext &exe_ctx) {
 101   ConstString watch_name("$__lldb__watch_value");
 102   m_old_value_sp = m_new_value_sp;
 103   Address watch_address(GetLoadAddress());
 104   if (!m_type.IsValid()) {
 105     // Don't know how to report new & old values, since we couldn't make a
 106     // scalar type for this watchpoint.
 107     // This works around an assert in ValueObjectMemory::Create.
 108     // FIXME: This should not happen, but if it does in some case we care about,
 109     // we can go grab the value raw and print it as unsigned.
 110     return false;
 111   }
 112   m_new_value_sp = ValueObjectMemory::Create(
 113       exe_ctx.GetBestExecutionContextScope(), watch_name.GetStringRef(),
 114       watch_address, m_type);
 115   m_new_value_sp = m_new_value_sp->CreateConstantValue(watch_name);
 116   return (m_new_value_sp && m_new_value_sp->GetError().Success());
 117 }
 118
 119 void Watchpoint::IncrementFalseAlarmsAndReviseHitCount() {
 120   ++m_false_alarms;
 121   if (m_false_alarms) {
 122     if (m_hit_count >= m_false_alarms) {
 123       m_hit_count -= m_false_alarms;
 124       m_false_alarms = 0;
 125     } else {
 126       m_false_alarms -= m_hit_count;
 127       m_hit_count = 0;
 128     }
 129   }
 130 }
 131
 132 // RETURNS - true if we should stop at this breakpoint, false if we
 133 // should continue.
 134
 135 bool Watchpoint::ShouldStop(StoppointCallbackContext *context) {
 136   IncrementHitCount();
 137
 138   if (!IsEnabled())
 139     return false;
 140
 141   return true;
 142 }
 143
 144 void Watchpoint::GetDescription(Stream *s, lldb::DescriptionLevel level) {
 145   DumpWithLevel(s, level);
 146 }
 147
 148 void Watchpoint::Dump(Stream *s) const {
 149   DumpWithLevel(s, lldb::eDescriptionLevelBrief);
 150 }
 151
 152 // If prefix is nullptr, we display the watch id and ignore the prefix
 153 // altogether.
 154 void Watchpoint::DumpSnapshots(Stream *s, const char *prefix) const {
 155   if (!prefix) {
 156     s->Printf("\nWatchpoint %u hit:", GetID());
 157     prefix = "";
 158   }
 159
 160   if (m_old_value_sp) {
 161     const char *old_value_cstr = m_old_value_sp->GetValueAsCString();
 162     if (old_value_cstr && old_value_cstr[0])
 163       s->Printf("\n%sold value: %s", prefix, old_value_cstr);
 164     else {
 165       const char *old_summary_cstr = m_old_value_sp->GetSummaryAsCString();
 166       if (old_summary_cstr && old_summary_cstr[0])
 167         s->Printf("\n%sold value: %s", prefix, old_summary_cstr);
 168     }
 169   }
 170
 171   if (m_new_value_sp) {
 172     const char *new_value_cstr = m_new_value_sp->GetValueAsCString();
 173     if (new_value_cstr && new_value_cstr[0])
 174       s->Printf("\n%snew value: %s", prefix, new_value_cstr);
 175     else {
 176       const char *new_summary_cstr = m_new_value_sp->GetSummaryAsCString();
 177       if (new_summary_cstr && new_summary_cstr[0])
 178         s->Printf("\n%snew value: %s", prefix, new_summary_cstr);
 179     }
 180   }
 181 }
 182
 183 void Watchpoint::DumpWithLevel(Stream *s,
 184                                lldb::DescriptionLevel description_level) const {
 185   if (s == nullptr)
 186     return;
 187
 188   assert(description_level >= lldb::eDescriptionLevelBrief &&
 189          description_level <= lldb::eDescriptionLevelVerbose);
 190
 191   s->Printf("Watchpoint %u: addr = 0x%8.8" PRIx64
 192             " size = %u state = %s type = %s%s",
 193             GetID(), GetLoadAddress(), m_byte_size,
 194             IsEnabled() ? "enabled" : "disabled", m_watch_read ? "r" : "",
 195             m_watch_write ? "w" : "");
 196
 197   if (description_level >= lldb::eDescriptionLevelFull) {
 198     if (!m_decl_str.empty())
 199       s->Printf("\n    declare @ '%s'", m_decl_str.c_str());
 200     if (!m_watch_spec_str.empty())
 201       s->Printf("\n    watchpoint spec = '%s'", m_watch_spec_str.c_str());
 202
 203     // Dump the snapshots we have taken.
 204     DumpSnapshots(s, "    ");
 205
 206     if (GetConditionText())
 207       s->Printf("\n    condition = '%s'", GetConditionText());
 208     m_options.GetCallbackDescription(s, description_level);
 209   }
 210
 211   if (description_level >= lldb::eDescriptionLevelVerbose) {
 212     s->Printf("\n    hw_index = %i  hit_count = %-4u  ignore_count = %-4u",
 213               GetHardwareIndex(), GetHitCount(), GetIgnoreCount());
 214   }
 215 }
 216
 217 bool Watchpoint::IsEnabled() const { return m_enabled; }
 218
 219 // Within StopInfo.cpp, we purposely turn on the ephemeral mode right before
 220 // temporarily disable the watchpoint
 221 // in order to perform possible watchpoint actions without triggering further
 222 // watchpoint events.
 223 // After the temporary disabled watchpoint is enabled, we then turn off the
 224 // ephemeral mode.
 225
 226 void Watchpoint::TurnOnEphemeralMode() { m_is_ephemeral = true; }
 227
 228 void Watchpoint::TurnOffEphemeralMode() {
 229   m_is_ephemeral = false;
 230   // Leaving ephemeral mode, reset the m_disabled_count!
 231   m_disabled_count = 0;
 232 }
 233
 234 bool Watchpoint::IsDisabledDuringEphemeralMode() {
 235   return m_disabled_count > 1 && m_is_ephemeral;
 236 }
 237
 238 void Watchpoint::SetEnabled(bool enabled, bool notify) {
 239   if (!enabled) {
 240     if (!m_is_ephemeral)
 241       SetHardwareIndex(LLDB_INVALID_INDEX32);
 242     else
 243       ++m_disabled_count;
 244
 245     // Don't clear the snapshots for now.
 246     // Within StopInfo.cpp, we purposely do disable/enable watchpoint while
 247     // performing watchpoint actions.
 248   }
 249   bool changed = enabled != m_enabled;
 250   m_enabled = enabled;
 251   if (notify && !m_is_ephemeral && changed)
 252     SendWatchpointChangedEvent(enabled ? eWatchpointEventTypeEnabled
 253                                        : eWatchpointEventTypeDisabled);
 254 }
 255
 256 void Watchpoint::SetWatchpointType(uint32_t type, bool notify) {
 257   int old_watch_read = m_watch_read;
 258   int old_watch_write = m_watch_write;
 259   m_watch_read = (type & LLDB_WATCH_TYPE_READ) != 0;
 260   m_watch_write = (type & LLDB_WATCH_TYPE_WRITE) != 0;
 261   if (notify &&
 262       (old_watch_read != m_watch_read || old_watch_write != m_watch_write))
 263     SendWatchpointChangedEvent(eWatchpointEventTypeTypeChanged);
 264 }
 265
 266 bool Watchpoint::WatchpointRead() const { return m_watch_read != 0; }
 267
 268 bool Watchpoint::WatchpointWrite() const { return m_watch_write != 0; }
 269
 270 uint32_t Watchpoint::GetIgnoreCount() const { return m_ignore_count; }
 271
 272 void Watchpoint::SetIgnoreCount(uint32_t n) {
 273   bool changed = m_ignore_count != n;
 274   m_ignore_count = n;
 275   if (changed)
 276     SendWatchpointChangedEvent(eWatchpointEventTypeIgnoreChanged);
 277 }
 278
 279 bool Watchpoint::InvokeCallback(StoppointCallbackContext *context) {
 280   return m_options.InvokeCallback(context, GetID());
 281 }
 282
 283 void Watchpoint::SetCondition(const char *condition) {
 284   if (condition == nullptr || condition[0] == '\0') {
 285     if (m_condition_ap.get())
 286       m_condition_ap.reset();
 287   } else {
 288     // Pass nullptr for expr_prefix (no translation-unit level definitions).
 289     Status error;
 290     m_condition_ap.reset(m_target.GetUserExpressionForLanguage(
 291         condition, llvm::StringRef(), lldb::eLanguageTypeUnknown,
 292         UserExpression::eResultTypeAny, EvaluateExpressionOptions(), error));
 293     if (error.Fail()) {
 294       // FIXME: Log something...
 295       m_condition_ap.reset();
 296     }
 297   }
 298   SendWatchpointChangedEvent(eWatchpointEventTypeConditionChanged);
 299 }
 300
 301 const char *Watchpoint::GetConditionText() const {
 302   if (m_condition_ap.get())
 303     return m_condition_ap->GetUserText();
 304   else
 305     return nullptr;
 306 }
 307
 308 void Watchpoint::SendWatchpointChangedEvent(
 309     lldb::WatchpointEventType eventKind) {
 310   if (!m_being_created &&
 311       GetTarget().EventTypeHasListeners(
 312           Target::eBroadcastBitWatchpointChanged)) {
 313     WatchpointEventData *data =
 314         new Watchpoint::WatchpointEventData(eventKind, shared_from_this());
 315     GetTarget().BroadcastEvent(Target::eBroadcastBitWatchpointChanged, data);
 316   }
 317 }
 318
 319 void Watchpoint::SendWatchpointChangedEvent(WatchpointEventData *data) {
 320   if (data == nullptr)
 321     return;
 322
 323   if (!m_being_created &&
 324       GetTarget().EventTypeHasListeners(Target::eBroadcastBitWatchpointChanged))
 325     GetTarget().BroadcastEvent(Target::eBroadcastBitWatchpointChanged, data);
 326   else
 327     delete data;
 328 }
 329
 330 Watchpoint::WatchpointEventData::WatchpointEventData(
 331     WatchpointEventType sub_type, const WatchpointSP &new_watchpoint_sp)
 332     : EventData(), m_watchpoint_event(sub_type),
 333       m_new_watchpoint_sp(new_watchpoint_sp) {}
 334
 335 Watchpoint::WatchpointEventData::~WatchpointEventData() = default;
 336
 337 const ConstString &Watchpoint::WatchpointEventData::GetFlavorString() {
 338   static ConstString g_flavor("Watchpoint::WatchpointEventData");
 339   return g_flavor;
 340 }
 341
 342 const ConstString &Watchpoint::WatchpointEventData::GetFlavor() const {
 343   return WatchpointEventData::GetFlavorString();
 344 }
 345
 346 WatchpointSP &Watchpoint::WatchpointEventData::GetWatchpoint() {
 347   return m_new_watchpoint_sp;
 348 }
 349
 350 WatchpointEventType
 351 Watchpoint::WatchpointEventData::GetWatchpointEventType() const {
 352   return m_watchpoint_event;
 353 }
 354
 355 void Watchpoint::WatchpointEventData::Dump(Stream *s) const {}
 356
 357 const Watchpoint::WatchpointEventData *
 358 Watchpoint::WatchpointEventData::GetEventDataFromEvent(const Event *event) {
 359   if (event) {
 360     const EventData *event_data = event->GetData();
 361     if (event_data &&
 362         event_data->GetFlavor() == WatchpointEventData::GetFlavorString())
 363       return static_cast<const WatchpointEventData *>(event->GetData());
 364   }
 365   return nullptr;
 366 }
 367
 368 WatchpointEventType
 369 Watchpoint::WatchpointEventData::GetWatchpointEventTypeFromEvent(
 370     const EventSP &event_sp) {
 371   const WatchpointEventData *data = GetEventDataFromEvent(event_sp.get());
 372
 373   if (data == nullptr)
 374     return eWatchpointEventTypeInvalidType;
 375   else
 376     return data->GetWatchpointEventType();
 377 }
 378
 379 WatchpointSP Watchpoint::WatchpointEventData::GetWatchpointFromEvent(
 380     const EventSP &event_sp) {
 381   WatchpointSP wp_sp;
 382
 383   const WatchpointEventData *data = GetEventDataFromEvent(event_sp.get());
 384   if (data)
 385     wp_sp = data->m_new_watchpoint_sp;
 386
 387   return wp_sp;
 388 }