//===-- InstrumentationRuntimeMainThreadChecker.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 "InstrumentationRuntimeMainThreadChecker.h"

#include "Plugins/Process/Utility/HistoryThread.h"

#include "lldb/Breakpoint/StoppointCallbackContext.h"

#include "lldb/Core/Module.h"

#include "lldb/Core/PluginManager.h"

#include "lldb/Symbol/Symbol.h"

#include "lldb/Symbol/SymbolContext.h"

#include "lldb/Symbol/Variable.h"

#include "lldb/Symbol/VariableList.h"

#include "lldb/Target/InstrumentationRuntimeStopInfo.h"

#include "lldb/Target/RegisterContext.h"

#include "lldb/Target/SectionLoadList.h"

#include "lldb/Target/StopInfo.h"

#include "lldb/Target/Target.h"

#include "lldb/Target/Thread.h"

#include "lldb/Utility/RegularExpression.h"

#include <memory>

using namespace lldb;

using namespace lldb_private;

LLDB_PLUGIN_DEFINE(InstrumentationRuntimeMainThreadChecker)

InstrumentationRuntimeMainThreadChecker::

    ~InstrumentationRuntimeMainThreadChecker() {

  Deactivate();

}

lldb::InstrumentationRuntimeSP

InstrumentationRuntimeMainThreadChecker::CreateInstance(

    const lldb::ProcessSP &process_sp) {

  return InstrumentationRuntimeSP(

      new InstrumentationRuntimeMainThreadChecker(process_sp));

}

void InstrumentationRuntimeMainThreadChecker::Initialize() {

  PluginManager::RegisterPlugin(

      GetPluginNameStatic(),

      "MainThreadChecker instrumentation runtime plugin.", CreateInstance,

      GetTypeStatic);

}

void InstrumentationRuntimeMainThreadChecker::Terminate() {

  PluginManager::UnregisterPlugin(CreateInstance);

}

lldb::InstrumentationRuntimeType

InstrumentationRuntimeMainThreadChecker::GetTypeStatic() {

  return eInstrumentationRuntimeTypeMainThreadChecker;

}

const RegularExpression &

InstrumentationRuntimeMainThreadChecker::GetPatternForRuntimeLibrary() {

  static RegularExpression regex(llvm::StringRef("libMainThreadChecker.dylib"));

  return regex;

}

bool InstrumentationRuntimeMainThreadChecker::CheckIfRuntimeIsValid(

    const lldb::ModuleSP module_sp) {

  static ConstString test_sym("__main_thread_checker_on_report");

  const Symbol *symbol =

      module_sp->FindFirstSymbolWithNameAndType(test_sym, lldb::eSymbolTypeAny);

  return symbol != nullptr;

}

StructuredData::ObjectSP

InstrumentationRuntimeMainThreadChecker::RetrieveReportData(

    ExecutionContextRef exe_ctx_ref) {

  ProcessSP process_sp = GetProcessSP();

  if (!process_sp)

    return StructuredData::ObjectSP();

  ThreadSP thread_sp = exe_ctx_ref.GetThreadSP();

  StackFrameSP frame_sp =

      thread_sp->GetSelectedFrame(DoNoSelectMostRelevantFrame);

  ModuleSP runtime_module_sp = GetRuntimeModuleSP();

  Target &target = process_sp->GetTarget();

  if (!frame_sp)

    return StructuredData::ObjectSP();

  RegisterContextSP regctx_sp = frame_sp->GetRegisterContext();

  if (!regctx_sp)

    return StructuredData::ObjectSP();

  const RegisterInfo *reginfo = regctx_sp->GetRegisterInfoByName("arg1");

  if (!reginfo)

    return StructuredData::ObjectSP();

  uint64_t apiname_ptr = regctx_sp->ReadRegisterAsUnsigned(reginfo, 0);

  if (!apiname_ptr)

    return StructuredData::ObjectSP();

  std::string apiName;

  Status read_error;

  target.ReadCStringFromMemory(apiname_ptr, apiName, read_error);

  if (read_error.Fail())

    return StructuredData::ObjectSP();

  std::string className;

  std::string selector;

  if (apiName.substr(0, 2) == "-[") {

    size_t spacePos = apiName.find(' ');

    if (spacePos != std::string::npos) {

      className = apiName.substr(2, spacePos - 2);

      selector = apiName.substr(spacePos + 1, apiName.length() - spacePos - 2);

    }

  }

  // Gather the PCs of the user frames in the backtrace.

  StructuredData::Array *trace = new StructuredData::Array();

  auto trace_sp = StructuredData::ObjectSP(trace);

  StackFrameSP responsible_frame;

  for (unsigned I = 0; I < thread_sp->GetStackFrameCount(); 
++I18
) {

    StackFrameSP frame = thread_sp->GetStackFrameAtIndex(I);

    Address addr = frame->GetFrameCodeAddressForSymbolication();

    if (addr.GetModule() == runtime_module_sp) // Skip PCs from the runtime.

      continue;

    // The first non-runtime frame is responsible for the bug.

    if (!responsible_frame)

      responsible_frame = frame;

    lldb::addr_t PC = addr.GetLoadAddress(&target);

    trace->AddIntegerItem(PC);

  }

  auto *d = new StructuredData::Dictionary();

  auto dict_sp = StructuredData::ObjectSP(d);

  d->AddStringItem("instrumentation_class", "MainThreadChecker");

  d->AddStringItem("api_name", apiName);

  d->AddStringItem("class_name", className);

  d->AddStringItem("selector", selector);

  d->AddStringItem("description",

                   apiName + " must be used from main thread only");

  d->AddIntegerItem("tid", thread_sp->GetIndexID());

  d->AddItem("trace", trace_sp);

  return dict_sp;

}

bool InstrumentationRuntimeMainThreadChecker::NotifyBreakpointHit(

    void *baton, StoppointCallbackContext *context, user_id_t break_id,

    user_id_t break_loc_id) {

  assert(baton && "null baton");

  if (!baton)

    return false; ///< false => resume execution.

  InstrumentationRuntimeMainThreadChecker *const instance =

      static_cast<InstrumentationRuntimeMainThreadChecker *>(baton);

  ProcessSP process_sp = instance->GetProcessSP();

  ThreadSP thread_sp = context->exe_ctx_ref.GetThreadSP();

  if (!process_sp || !thread_sp ||

      process_sp != context->exe_ctx_ref.GetProcessSP())

    return false;

  if (process_sp->GetModIDRef().IsLastResumeForUserExpression())

    return false;

  StructuredData::ObjectSP report =

      instance->RetrieveReportData(context->exe_ctx_ref);

  if (report) {

    std::string description = std::string(report->GetAsDictionary()

                                              ->GetValueForKey("description")

                                              ->GetAsString()

                                              ->GetValue());

    thread_sp->SetStopInfo(

        InstrumentationRuntimeStopInfo::CreateStopReasonWithInstrumentationData(

            *thread_sp, description, report));

    return true;

  }

  return false;

}

void InstrumentationRuntimeMainThreadChecker::Activate() {

  if (IsActive())

    return;

  ProcessSP process_sp = GetProcessSP();

  if (!process_sp)

    return;

  ModuleSP runtime_module_sp = GetRuntimeModuleSP();

  ConstString symbol_name("__main_thread_checker_on_report");

  const Symbol *symbol = runtime_module_sp->FindFirstSymbolWithNameAndType(

      symbol_name, eSymbolTypeCode);

  if (symbol == nullptr)

    return;

  if (!symbol->ValueIsAddress() || !symbol->GetAddressRef().IsValid())

    return;

  Target &target = process_sp->GetTarget();

  addr_t symbol_address = symbol->GetAddressRef().GetOpcodeLoadAddress(&target);

  if (symbol_address == LLDB_INVALID_ADDRESS)

    return;

  Breakpoint *breakpoint =

      process_sp->GetTarget()

          .CreateBreakpoint(symbol_address, /*internal=*/true,

                            /*hardware=*/false)

          .get();

  const bool sync = false;

  breakpoint->SetCallback(

      InstrumentationRuntimeMainThreadChecker::NotifyBreakpointHit, this, sync);

  breakpoint->SetBreakpointKind("main-thread-checker-report");

  SetBreakpointID(breakpoint->GetID());

  SetActive(true);

}

void InstrumentationRuntimeMainThreadChecker::Deactivate() {

  SetActive(false);

  auto BID = GetBreakpointID();

  if (BID == LLDB_INVALID_BREAK_ID)

    return;

  if (ProcessSP process_sp = GetProcessSP()) {

    process_sp->GetTarget().RemoveBreakpointByID(BID);

    SetBreakpointID(LLDB_INVALID_BREAK_ID);

  }

}

lldb::ThreadCollectionSP

InstrumentationRuntimeMainThreadChecker::GetBacktracesFromExtendedStopInfo(

    StructuredData::ObjectSP info) {

  ThreadCollectionSP threads;

  threads = std::make_shared<ThreadCollection>();

  ProcessSP process_sp = GetProcessSP();

  if (info->GetObjectForDotSeparatedPath("instrumentation_class")

          ->GetStringValue() != "MainThreadChecker")

    return threads;

  std::vector<lldb::addr_t> PCs;

  auto trace = info->GetObjectForDotSeparatedPath("trace")->GetAsArray();

  trace->ForEach([&PCs](StructuredData::Object *PC) -> bool {

    PCs.push_back(PC->GetUnsignedIntegerValue());

    return true;

  });

  if (PCs.empty())

    return threads;

  StructuredData::ObjectSP thread_id_obj =

      info->GetObjectForDotSeparatedPath("tid");

  tid_t tid = thread_id_obj ? thread_id_obj->GetUnsignedIntegerValue() : 0;

  // We gather symbolication addresses above, so no need for HistoryThread to

  // try to infer the call addresses.

  bool pcs_are_call_addresses = true;

  ThreadSP new_thread_sp = std::make_shared<HistoryThread>(

      *process_sp, tid, PCs, pcs_are_call_addresses);

  // Save this in the Process' ExtendedThreadList so a strong pointer retains

  // the object

  process_sp->GetExtendedThreadList().AddThread(new_thread_sp);

  threads->AddThread(new_thread_sp);

  return threads;

}