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