Coverage Report

Created: 2022-01-25 06:29

/Users/buildslave/jenkins/workspace/coverage/llvm-project/lldb/source/Plugins/InstrumentationRuntime/UBSan/InstrumentationRuntimeUBSan.cpp
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//===-- InstrumentationRuntimeUBSan.cpp -----------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "InstrumentationRuntimeUBSan.h"
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#include "Plugins/Process/Utility/HistoryThread.h"
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#include "lldb/Breakpoint/StoppointCallbackContext.h"
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#include "lldb/Core/Debugger.h"
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#include "lldb/Core/Module.h"
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#include "lldb/Core/PluginInterface.h"
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#include "lldb/Core/PluginManager.h"
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#include "lldb/Core/StreamFile.h"
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#include "lldb/Core/ValueObject.h"
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#include "lldb/Expression/UserExpression.h"
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#include "lldb/Interpreter/CommandReturnObject.h"
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#include "lldb/Symbol/Symbol.h"
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#include "lldb/Symbol/SymbolContext.h"
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#include "lldb/Symbol/Variable.h"
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#include "lldb/Symbol/VariableList.h"
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#include "lldb/Target/InstrumentationRuntimeStopInfo.h"
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#include "lldb/Target/SectionLoadList.h"
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#include "lldb/Target/StopInfo.h"
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#include "lldb/Target/Target.h"
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#include "lldb/Target/Thread.h"
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#include "lldb/Utility/RegularExpression.h"
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#include "lldb/Utility/Stream.h"
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#include <cctype>
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#include <memory>
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using namespace lldb;
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using namespace lldb_private;
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LLDB_PLUGIN_DEFINE(InstrumentationRuntimeUBSan)
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InstrumentationRuntimeUBSan::~InstrumentationRuntimeUBSan() { Deactivate(); }
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lldb::InstrumentationRuntimeSP
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InstrumentationRuntimeUBSan::CreateInstance(const lldb::ProcessSP &process_sp) {
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  return InstrumentationRuntimeSP(new InstrumentationRuntimeUBSan(process_sp));
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}
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void InstrumentationRuntimeUBSan::Initialize() {
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  PluginManager::RegisterPlugin(
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      GetPluginNameStatic(),
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      "UndefinedBehaviorSanitizer instrumentation runtime plugin.",
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      CreateInstance, GetTypeStatic);
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}
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void InstrumentationRuntimeUBSan::Terminate() {
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  PluginManager::UnregisterPlugin(CreateInstance);
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}
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lldb::InstrumentationRuntimeType InstrumentationRuntimeUBSan::GetTypeStatic() {
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  return eInstrumentationRuntimeTypeUndefinedBehaviorSanitizer;
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}
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static const char *ub_sanitizer_retrieve_report_data_prefix = R"(
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extern "C" {
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void
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__ubsan_get_current_report_data(const char **OutIssueKind,
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    const char **OutMessage, const char **OutFilename, unsigned *OutLine,
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    unsigned *OutCol, char **OutMemoryAddr);
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}
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struct data {
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  const char *issue_kind;
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  const char *message;
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  const char *filename;
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  unsigned line;
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  unsigned col;
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  char *memory_addr;
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};
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)";
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static const char *ub_sanitizer_retrieve_report_data_command = R"(
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data t;
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__ubsan_get_current_report_data(&t.issue_kind, &t.message, &t.filename, &t.line,
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                                &t.col, &t.memory_addr);
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t;
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)";
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static addr_t RetrieveUnsigned(ValueObjectSP return_value_sp,
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                               ProcessSP process_sp,
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                               const std::string &expression_path) {
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  return return_value_sp->GetValueForExpressionPath(expression_path.c_str())
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      ->GetValueAsUnsigned(0);
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}
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static std::string RetrieveString(ValueObjectSP return_value_sp,
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                                  ProcessSP process_sp,
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                                  const std::string &expression_path) {
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  addr_t ptr = RetrieveUnsigned(return_value_sp, process_sp, expression_path);
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  std::string str;
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  Status error;
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  process_sp->ReadCStringFromMemory(ptr, str, error);
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  return str;
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}
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StructuredData::ObjectSP InstrumentationRuntimeUBSan::RetrieveReportData(
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    ExecutionContextRef exe_ctx_ref) {
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  ProcessSP process_sp = GetProcessSP();
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  if (!process_sp)
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    return StructuredData::ObjectSP();
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  ThreadSP thread_sp = exe_ctx_ref.GetThreadSP();
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  StackFrameSP frame_sp = thread_sp->GetSelectedFrame();
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  ModuleSP runtime_module_sp = GetRuntimeModuleSP();
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  Target &target = process_sp->GetTarget();
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  if (!frame_sp)
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    return StructuredData::ObjectSP();
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  StreamFileSP Stream = target.GetDebugger().GetOutputStreamSP();
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  EvaluateExpressionOptions options;
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  options.SetUnwindOnError(true);
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  options.SetTryAllThreads(true);
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  options.SetStopOthers(true);
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  options.SetIgnoreBreakpoints(true);
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  options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
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  options.SetPrefix(ub_sanitizer_retrieve_report_data_prefix);
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  options.SetAutoApplyFixIts(false);
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  options.SetLanguage(eLanguageTypeObjC_plus_plus);
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  ValueObjectSP main_value;
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  ExecutionContext exe_ctx;
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  Status eval_error;
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  frame_sp->CalculateExecutionContext(exe_ctx);
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  ExpressionResults result = UserExpression::Evaluate(
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      exe_ctx, options, ub_sanitizer_retrieve_report_data_command, "",
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      main_value, eval_error);
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  if (result != eExpressionCompleted) {
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    target.GetDebugger().GetAsyncOutputStream()->Printf(
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        "Warning: Cannot evaluate UndefinedBehaviorSanitizer expression:\n%s\n",
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        eval_error.AsCString());
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    return StructuredData::ObjectSP();
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  }
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  // Gather the PCs of the user frames in the backtrace.
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  StructuredData::Array *trace = new StructuredData::Array();
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  auto trace_sp = StructuredData::ObjectSP(trace);
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  for (unsigned I = 0; I < thread_sp->GetStackFrameCount(); ++I) {
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    const Address FCA = thread_sp->GetStackFrameAtIndex(I)
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                            ->GetFrameCodeAddressForSymbolication();
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    if (FCA.GetModule() == runtime_module_sp) // Skip PCs from the runtime.
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      continue;
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    lldb::addr_t PC = FCA.GetLoadAddress(&target);
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    trace->AddItem(StructuredData::ObjectSP(new StructuredData::Integer(PC)));
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  }
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  std::string IssueKind = RetrieveString(main_value, process_sp, ".issue_kind");
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  std::string ErrMessage = RetrieveString(main_value, process_sp, ".message");
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  std::string Filename = RetrieveString(main_value, process_sp, ".filename");
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  unsigned Line = RetrieveUnsigned(main_value, process_sp, ".line");
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  unsigned Col = RetrieveUnsigned(main_value, process_sp, ".col");
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  uintptr_t MemoryAddr =
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      RetrieveUnsigned(main_value, process_sp, ".memory_addr");
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  auto *d = new StructuredData::Dictionary();
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  auto dict_sp = StructuredData::ObjectSP(d);
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  d->AddStringItem("instrumentation_class", "UndefinedBehaviorSanitizer");
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  d->AddStringItem("description", IssueKind);
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  d->AddStringItem("summary", ErrMessage);
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  d->AddStringItem("filename", Filename);
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  d->AddIntegerItem("line", Line);
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  d->AddIntegerItem("col", Col);
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  d->AddIntegerItem("memory_address", MemoryAddr);
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  d->AddIntegerItem("tid", thread_sp->GetID());
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  d->AddItem("trace", trace_sp);
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  return dict_sp;
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}
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static std::string GetStopReasonDescription(StructuredData::ObjectSP report) {
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  llvm::StringRef stop_reason_description_ref;
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  report->GetAsDictionary()->GetValueForKeyAsString(
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      "description", stop_reason_description_ref);
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  std::string stop_reason_description =
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      std::string(stop_reason_description_ref);
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  if (!stop_reason_description.size()) {
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    stop_reason_description = "Undefined behavior detected";
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  } else {
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    stop_reason_description[0] = toupper(stop_reason_description[0]);
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    for (unsigned I = 1; I < stop_reason_description.size(); ++I)
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      if (stop_reason_description[I] == '-')
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        stop_reason_description[I] = ' ';
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  }
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  return stop_reason_description;
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}
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bool InstrumentationRuntimeUBSan::NotifyBreakpointHit(
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    void *baton, StoppointCallbackContext *context, user_id_t break_id,
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    user_id_t break_loc_id) {
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  assert(baton && "null baton");
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  if (!baton)
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    return false; ///< false => resume execution.
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  InstrumentationRuntimeUBSan *const instance =
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      static_cast<InstrumentationRuntimeUBSan *>(baton);
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  ProcessSP process_sp = instance->GetProcessSP();
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  ThreadSP thread_sp = context->exe_ctx_ref.GetThreadSP();
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  if (!process_sp || !thread_sp ||
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      process_sp != context->exe_ctx_ref.GetProcessSP())
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    return false;
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  if (process_sp->GetModIDRef().IsLastResumeForUserExpression())
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    return false;
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  StructuredData::ObjectSP report =
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      instance->RetrieveReportData(context->exe_ctx_ref);
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  if (report) {
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    thread_sp->SetStopInfo(
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        InstrumentationRuntimeStopInfo::CreateStopReasonWithInstrumentationData(
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            *thread_sp, GetStopReasonDescription(report), report));
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    return true;
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  }
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  return false;
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}
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const RegularExpression &
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InstrumentationRuntimeUBSan::GetPatternForRuntimeLibrary() {
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  static RegularExpression regex(llvm::StringRef("libclang_rt\\.(a|t|ub)san_"));
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  return regex;
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}
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bool InstrumentationRuntimeUBSan::CheckIfRuntimeIsValid(
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    const lldb::ModuleSP module_sp) {
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  static ConstString ubsan_test_sym("__ubsan_on_report");
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  const Symbol *symbol = module_sp->FindFirstSymbolWithNameAndType(
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      ubsan_test_sym, lldb::eSymbolTypeAny);
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  return symbol != nullptr;
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}
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// FIXME: Factor out all the logic we have in common with the {a,t}san plugins.
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void InstrumentationRuntimeUBSan::Activate() {
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  if (IsActive())
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    return;
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  ProcessSP process_sp = GetProcessSP();
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  if (!process_sp)
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    return;
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  ModuleSP runtime_module_sp = GetRuntimeModuleSP();
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  ConstString symbol_name("__ubsan_on_report");
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  const Symbol *symbol = runtime_module_sp->FindFirstSymbolWithNameAndType(
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      symbol_name, eSymbolTypeCode);
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  if (symbol == nullptr)
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    return;
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  if (!symbol->ValueIsAddress() || !symbol->GetAddressRef().IsValid())
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    return;
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  Target &target = process_sp->GetTarget();
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  addr_t symbol_address = symbol->GetAddressRef().GetOpcodeLoadAddress(&target);
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  if (symbol_address == LLDB_INVALID_ADDRESS)
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    return;
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  Breakpoint *breakpoint =
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      process_sp->GetTarget()
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          .CreateBreakpoint(symbol_address, /*internal=*/true,
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                            /*hardware=*/false)
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          .get();
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  breakpoint->SetCallback(InstrumentationRuntimeUBSan::NotifyBreakpointHit,
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                          this, true);
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  breakpoint->SetBreakpointKind("undefined-behavior-sanitizer-report");
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  SetBreakpointID(breakpoint->GetID());
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  SetActive(true);
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}
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void InstrumentationRuntimeUBSan::Deactivate() {
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  SetActive(false);
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  auto BID = GetBreakpointID();
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  if (BID == LLDB_INVALID_BREAK_ID)
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    return;
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  if (ProcessSP process_sp = GetProcessSP()) {
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    process_sp->GetTarget().RemoveBreakpointByID(BID);
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    SetBreakpointID(LLDB_INVALID_BREAK_ID);
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  }
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}
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lldb::ThreadCollectionSP
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InstrumentationRuntimeUBSan::GetBacktracesFromExtendedStopInfo(
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    StructuredData::ObjectSP info) {
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  ThreadCollectionSP threads;
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  threads = std::make_shared<ThreadCollection>();
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  ProcessSP process_sp = GetProcessSP();
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  if (info->GetObjectForDotSeparatedPath("instrumentation_class")
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          ->GetStringValue() != "UndefinedBehaviorSanitizer")
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    return threads;
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  std::vector<lldb::addr_t> PCs;
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  auto trace = info->GetObjectForDotSeparatedPath("trace")->GetAsArray();
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  trace->ForEach([&PCs](StructuredData::Object *PC) -> bool {
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    PCs.push_back(PC->GetAsInteger()->GetValue());
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    return true;
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  });
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  if (PCs.empty())
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    return threads;
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  StructuredData::ObjectSP thread_id_obj =
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      info->GetObjectForDotSeparatedPath("tid");
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  tid_t tid = thread_id_obj ? thread_id_obj->GetIntegerValue() : 0;
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  // We gather symbolication addresses above, so no need for HistoryThread to
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  // try to infer the call addresses.
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  bool pcs_are_call_addresses = true;
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  ThreadSP new_thread_sp = std::make_shared<HistoryThread>(
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      *process_sp, tid, PCs, pcs_are_call_addresses);
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  std::string stop_reason_description = GetStopReasonDescription(info);
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  new_thread_sp->SetName(stop_reason_description.c_str());
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  // Save this in the Process' ExtendedThreadList so a strong pointer retains
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  // the object
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  process_sp->GetExtendedThreadList().AddThread(new_thread_sp);
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  threads->AddThread(new_thread_sp);
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  return threads;
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}