lldb/source/Commands/CommandObjectExpression.cpp

   1 //===-- CommandObjectExpression.cpp ---------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/ADT/StringRef.h"
  10
  11 #include "CommandObjectExpression.h"
  12 #include "lldb/Core/Debugger.h"
  13 #include "lldb/Expression/ExpressionVariable.h"
  14 #include "lldb/Expression/REPL.h"
  15 #include "lldb/Expression/UserExpression.h"
  16 #include "lldb/Host/OptionParser.h"
  17 #include "lldb/Interpreter/CommandInterpreter.h"
  18 #include "lldb/Interpreter/CommandOptionArgumentTable.h"
  19 #include "lldb/Interpreter/CommandReturnObject.h"
  20 #include "lldb/Interpreter/OptionArgParser.h"
  21 #include "lldb/Target/Language.h"
  22 #include "lldb/Target/Process.h"
  23 #include "lldb/Target/StackFrame.h"
  24 #include "lldb/Target/Target.h"
  25 #include "lldb/lldb-enumerations.h"
  26 #include "lldb/lldb-private-enumerations.h"
  27
  28 using namespace lldb;
  29 using namespace lldb_private;
  30
  31 CommandObjectExpression::CommandOptions::CommandOptions() = default;
  32
  33 CommandObjectExpression::CommandOptions::~CommandOptions() = default;
  34
  35 #define LLDB_OPTIONS_expression
  36 #include "CommandOptions.inc"
  37
  38 Status CommandObjectExpression::CommandOptions::SetOptionValue(
  39     uint32_t option_idx, llvm::StringRef option_arg,
  40     ExecutionContext *execution_context) {
  41   Status error;
  42
  43   const int short_option = GetDefinitions()[option_idx].short_option;
  44
  45   switch (short_option) {
  46   case 'l':
  47     language = Language::GetLanguageTypeFromString(option_arg);
  48     if (language == eLanguageTypeUnknown) {
  49       StreamString sstr;
  50       sstr.Printf("unknown language type: '%s' for expression. "
  51                   "List of supported languages:\n",
  52                   option_arg.str().c_str());
  53
  54       Language::PrintSupportedLanguagesForExpressions(sstr, "  ", "\n");
  55       error.SetErrorString(sstr.GetString());
  56     }
  57     break;
  58
  59   case 'a': {
  60     bool success;
  61     bool result;
  62     result = OptionArgParser::ToBoolean(option_arg, true, &success);
  63     if (!success)
  64       error.SetErrorStringWithFormat(
  65           "invalid all-threads value setting: \"%s\"",
  66           option_arg.str().c_str());
  67     else
  68       try_all_threads = result;
  69   } break;
  70
  71   case 'i': {
  72     bool success;
  73     bool tmp_value = OptionArgParser::ToBoolean(option_arg, true, &success);
  74     if (success)
  75       ignore_breakpoints = tmp_value;
  76     else
  77       error.SetErrorStringWithFormat(
  78           "could not convert \"%s\" to a boolean value.",
  79           option_arg.str().c_str());
  80     break;
  81   }
  82
  83   case 'j': {
  84     bool success;
  85     bool tmp_value = OptionArgParser::ToBoolean(option_arg, true, &success);
  86     if (success)
  87       allow_jit = tmp_value;
  88     else
  89       error.SetErrorStringWithFormat(
  90           "could not convert \"%s\" to a boolean value.",
  91           option_arg.str().c_str());
  92     break;
  93   }
  94
  95   case 't':
  96     if (option_arg.getAsInteger(0, timeout)) {
  97       timeout = 0;
  98       error.SetErrorStringWithFormat("invalid timeout setting \"%s\"",
  99                                      option_arg.str().c_str());
 100     }
 101     break;
 102
 103   case 'u': {
 104     bool success;
 105     bool tmp_value = OptionArgParser::ToBoolean(option_arg, true, &success);
 106     if (success)
 107       unwind_on_error = tmp_value;
 108     else
 109       error.SetErrorStringWithFormat(
 110           "could not convert \"%s\" to a boolean value.",
 111           option_arg.str().c_str());
 112     break;
 113   }
 114
 115   case 'v':
 116     if (option_arg.empty()) {
 117       m_verbosity = eLanguageRuntimeDescriptionDisplayVerbosityFull;
 118       break;
 119     }
 120     m_verbosity = (LanguageRuntimeDescriptionDisplayVerbosity)
 121         OptionArgParser::ToOptionEnum(
 122             option_arg, GetDefinitions()[option_idx].enum_values, 0, error);
 123     if (!error.Success())
 124       error.SetErrorStringWithFormat(
 125           "unrecognized value for description-verbosity '%s'",
 126           option_arg.str().c_str());
 127     break;
 128
 129   case 'g':
 130     debug = true;
 131     unwind_on_error = false;
 132     ignore_breakpoints = false;
 133     break;
 134
 135   case 'p':
 136     top_level = true;
 137     break;
 138
 139   case 'X': {
 140     bool success;
 141     bool tmp_value = OptionArgParser::ToBoolean(option_arg, true, &success);
 142     if (success)
 143       auto_apply_fixits = tmp_value ? eLazyBoolYes : eLazyBoolNo;
 144     else
 145       error.SetErrorStringWithFormat(
 146           "could not convert \"%s\" to a boolean value.",
 147           option_arg.str().c_str());
 148     break;
 149   }
 150
 151   case '\x01': {
 152     bool success;
 153     bool persist_result =
 154         OptionArgParser::ToBoolean(option_arg, true, &success);
 155     if (success)
 156       suppress_persistent_result = !persist_result ? eLazyBoolYes : eLazyBoolNo;
 157     else
 158       error.SetErrorStringWithFormat(
 159           "could not convert \"%s\" to a boolean value.",
 160           option_arg.str().c_str());
 161     break;
 162   }
 163
 164   default:
 165     llvm_unreachable("Unimplemented option");
 166   }
 167
 168   return error;
 169 }
 170
 171 void CommandObjectExpression::CommandOptions::OptionParsingStarting(
 172     ExecutionContext *execution_context) {
 173   auto process_sp =
 174       execution_context ? execution_context->GetProcessSP() : ProcessSP();
 175   if (process_sp) {
 176     ignore_breakpoints = process_sp->GetIgnoreBreakpointsInExpressions();
 177     unwind_on_error = process_sp->GetUnwindOnErrorInExpressions();
 178   } else {
 179     ignore_breakpoints = true;
 180     unwind_on_error = true;
 181   }
 182
 183   show_summary = true;
 184   try_all_threads = true;
 185   timeout = 0;
 186   debug = false;
 187   language = eLanguageTypeUnknown;
 188   m_verbosity = eLanguageRuntimeDescriptionDisplayVerbosityCompact;
 189   auto_apply_fixits = eLazyBoolCalculate;
 190   top_level = false;
 191   allow_jit = true;
 192   suppress_persistent_result = eLazyBoolCalculate;
 193 }
 194
 195 llvm::ArrayRef<OptionDefinition>
 196 CommandObjectExpression::CommandOptions::GetDefinitions() {
 197   return llvm::ArrayRef(g_expression_options);
 198 }
 199
 200 EvaluateExpressionOptions
 201 CommandObjectExpression::CommandOptions::GetEvaluateExpressionOptions(
 202     const Target &target, const OptionGroupValueObjectDisplay &display_opts) {
 203   EvaluateExpressionOptions options;
 204   options.SetCoerceToId(display_opts.use_objc);
 205   options.SetUnwindOnError(unwind_on_error);
 206   options.SetIgnoreBreakpoints(ignore_breakpoints);
 207   options.SetKeepInMemory(true);
 208   options.SetUseDynamic(display_opts.use_dynamic);
 209   options.SetTryAllThreads(try_all_threads);
 210   options.SetDebug(debug);
 211   options.SetLanguage(language);
 212   options.SetExecutionPolicy(
 213       allow_jit ? EvaluateExpressionOptions::default_execution_policy
 214                 : lldb_private::eExecutionPolicyNever);
 215
 216   bool auto_apply_fixits;
 217   if (this->auto_apply_fixits == eLazyBoolCalculate)
 218     auto_apply_fixits = target.GetEnableAutoApplyFixIts();
 219   else
 220     auto_apply_fixits = this->auto_apply_fixits == eLazyBoolYes;
 221
 222   options.SetAutoApplyFixIts(auto_apply_fixits);
 223   options.SetRetriesWithFixIts(target.GetNumberOfRetriesWithFixits());
 224
 225   if (top_level)
 226     options.SetExecutionPolicy(eExecutionPolicyTopLevel);
 227
 228   // If there is any chance we are going to stop and want to see what went
 229   // wrong with our expression, we should generate debug info
 230   if (!ignore_breakpoints || !unwind_on_error)
 231     options.SetGenerateDebugInfo(true);
 232
 233   if (timeout > 0)
 234     options.SetTimeout(std::chrono::microseconds(timeout));
 235   else
 236     options.SetTimeout(std::nullopt);
 237   return options;
 238 }
 239
 240 bool CommandObjectExpression::CommandOptions::ShouldSuppressResult(
 241     const OptionGroupValueObjectDisplay &display_opts) const {
 242   // Explicitly disabling persistent results takes precedence over the
 243   // m_verbosity/use_objc logic.
 244   if (suppress_persistent_result != eLazyBoolCalculate)
 245     return suppress_persistent_result == eLazyBoolYes;
 246
 247   return display_opts.use_objc &&
 248          m_verbosity == eLanguageRuntimeDescriptionDisplayVerbosityCompact;
 249 }
 250
 251 CommandObjectExpression::CommandObjectExpression(
 252     CommandInterpreter &interpreter)
 253     : CommandObjectRaw(interpreter, "expression",
 254                        "Evaluate an expression on the current "
 255                        "thread.  Displays any returned value "
 256                        "with LLDB's default formatting.",
 257                        "",
 258                        eCommandProcessMustBePaused | eCommandTryTargetAPILock),
 259       IOHandlerDelegate(IOHandlerDelegate::Completion::Expression),
 260       m_format_options(eFormatDefault),
 261       m_repl_option(LLDB_OPT_SET_1, false, "repl", 'r', "Drop into REPL", false,
 262                     true),
 263       m_expr_line_count(0) {
 264   SetHelpLong(
 265       R"(
 266 Single and multi-line expressions:
 267
 268 )"
 269       "    The expression provided on the command line must be a complete expression \
 270 with no newlines.  To evaluate a multi-line expression, \
 271 hit a return after an empty expression, and lldb will enter the multi-line expression editor. \
 272 Hit return on an empty line to end the multi-line expression."
 273
 274       R"(
 275
 276 Timeouts:
 277
 278 )"
 279       "    If the expression can be evaluated statically (without running code) then it will be.  \
 280 Otherwise, by default the expression will run on the current thread with a short timeout: \
 281 currently .25 seconds.  If it doesn't return in that time, the evaluation will be interrupted \
 282 and resumed with all threads running.  You can use the -a option to disable retrying on all \
 283 threads.  You can use the -t option to set a shorter timeout."
 284       R"(
 285
 286 User defined variables:
 287
 288 )"
 289       "    You can define your own variables for convenience or to be used in subsequent expressions.  \
 290 You define them the same way you would define variables in C.  If the first character of \
 291 your user defined variable is a $, then the variable's value will be available in future \
 292 expressions, otherwise it will just be available in the current expression."
 293       R"(
 294
 295 Continuing evaluation after a breakpoint:
 296
 297 )"
 298       "    If the \"-i false\" option is used, and execution is interrupted by a breakpoint hit, once \
 299 you are done with your investigation, you can either remove the expression execution frames \
 300 from the stack with \"thread return -x\" or if you are still interested in the expression result \
 301 you can issue the \"continue\" command and the expression evaluation will complete and the \
 302 expression result will be available using the \"thread.completed-expression\" key in the thread \
 303 format."
 304
 305       R"(
 306
 307 Examples:
 308
 309     expr my_struct->a = my_array[3]
 310     expr -f bin -- (index * 8) + 5
 311     expr unsigned int $foo = 5
 312     expr char c[] = \"foo\"; c[0])");
 313
 314   CommandArgumentEntry arg;
 315   CommandArgumentData expression_arg;
 316
 317   // Define the first (and only) variant of this arg.
 318   expression_arg.arg_type = eArgTypeExpression;
 319   expression_arg.arg_repetition = eArgRepeatPlain;
 320
 321   // There is only one variant this argument could be; put it into the argument
 322   // entry.
 323   arg.push_back(expression_arg);
 324
 325   // Push the data for the first argument into the m_arguments vector.
 326   m_arguments.push_back(arg);
 327
 328   // Add the "--format" and "--gdb-format"
 329   m_option_group.Append(&m_format_options,
 330                         OptionGroupFormat::OPTION_GROUP_FORMAT |
 331                             OptionGroupFormat::OPTION_GROUP_GDB_FMT,
 332                         LLDB_OPT_SET_1);
 333   m_option_group.Append(&m_command_options);
 334   m_option_group.Append(&m_varobj_options, LLDB_OPT_SET_ALL,
 335                         LLDB_OPT_SET_1 | LLDB_OPT_SET_2);
 336   m_option_group.Append(&m_repl_option, LLDB_OPT_SET_ALL, LLDB_OPT_SET_3);
 337   m_option_group.Finalize();
 338 }
 339
 340 CommandObjectExpression::~CommandObjectExpression() = default;
 341
 342 Options *CommandObjectExpression::GetOptions() { return &m_option_group; }
 343
 344 void CommandObjectExpression::HandleCompletion(CompletionRequest &request) {
 345   EvaluateExpressionOptions options;
 346   options.SetCoerceToId(m_varobj_options.use_objc);
 347   options.SetLanguage(m_command_options.language);
 348   options.SetExecutionPolicy(lldb_private::eExecutionPolicyNever);
 349   options.SetAutoApplyFixIts(false);
 350   options.SetGenerateDebugInfo(false);
 351
 352   ExecutionContext exe_ctx(m_interpreter.GetExecutionContext());
 353
 354   // Get out before we start doing things that expect a valid frame pointer.
 355   if (exe_ctx.GetFramePtr() == nullptr)
 356     return;
 357
 358   Target *exe_target = exe_ctx.GetTargetPtr();
 359   Target &target = exe_target ? *exe_target : GetDummyTarget();
 360
 361   unsigned cursor_pos = request.GetRawCursorPos();
 362   // Get the full user input including the suffix. The suffix is necessary
 363   // as OptionsWithRaw will use it to detect if the cursor is cursor is in the
 364   // argument part of in the raw input part of the arguments. If we cut of
 365   // of the suffix then "expr -arg[cursor] --" would interpret the "-arg" as
 366   // the raw input (as the "--" is hidden in the suffix).
 367   llvm::StringRef code = request.GetRawLineWithUnusedSuffix();
 368
 369   const std::size_t original_code_size = code.size();
 370
 371   // Remove the first token which is 'expr' or some alias/abbreviation of that.
 372   code = llvm::getToken(code).second.ltrim();
 373   OptionsWithRaw args(code);
 374   code = args.GetRawPart();
 375
 376   // The position where the expression starts in the command line.
 377   assert(original_code_size >= code.size());
 378   std::size_t raw_start = original_code_size - code.size();
 379
 380   // Check if the cursor is actually in the expression string, and if not, we
 381   // exit.
 382   // FIXME: We should complete the options here.
 383   if (cursor_pos < raw_start)
 384     return;
 385
 386   // Make the cursor_pos again relative to the start of the code string.
 387   assert(cursor_pos >= raw_start);
 388   cursor_pos -= raw_start;
 389
 390   auto language = exe_ctx.GetFrameRef().GetLanguage();
 391
 392   Status error;
 393   lldb::UserExpressionSP expr(target.GetUserExpressionForLanguage(
 394       code, llvm::StringRef(), language, UserExpression::eResultTypeAny,
 395       options, nullptr, error));
 396   if (error.Fail())
 397     return;
 398
 399   expr->Complete(exe_ctx, request, cursor_pos);
 400 }
 401
 402 static lldb_private::Status
 403 CanBeUsedForElementCountPrinting(ValueObject &valobj) {
 404   CompilerType type(valobj.GetCompilerType());
 405   CompilerType pointee;
 406   if (!type.IsPointerType(&pointee))
 407     return Status("as it does not refer to a pointer");
 408   if (pointee.IsVoidType())
 409     return Status("as it refers to a pointer to void");
 410   return Status();
 411 }
 412
 413 bool CommandObjectExpression::EvaluateExpression(llvm::StringRef expr,
 414                                                  Stream &output_stream,
 415                                                  Stream &error_stream,
 416                                                  CommandReturnObject &result) {
 417   // Don't use m_exe_ctx as this might be called asynchronously after the
 418   // command object DoExecute has finished when doing multi-line expression
 419   // that use an input reader...
 420   ExecutionContext exe_ctx(m_interpreter.GetExecutionContext());
 421   Target *exe_target = exe_ctx.GetTargetPtr();
 422   Target &target = exe_target ? *exe_target : GetDummyTarget();
 423
 424   lldb::ValueObjectSP result_valobj_sp;
 425   StackFrame *frame = exe_ctx.GetFramePtr();
 426
 427   if (m_command_options.top_level && !m_command_options.allow_jit) {
 428     result.AppendErrorWithFormat(
 429         "Can't disable JIT compilation for top-level expressions.\n");
 430     return false;
 431   }
 432
 433   EvaluateExpressionOptions eval_options =
 434       m_command_options.GetEvaluateExpressionOptions(target, m_varobj_options);
 435   // This command manually removes the result variable, make sure expression
 436   // evaluation doesn't do it first.
 437   eval_options.SetSuppressPersistentResult(false);
 438
 439   ExpressionResults success = target.EvaluateExpression(
 440       expr, frame, result_valobj_sp, eval_options, &m_fixed_expression);
 441
 442   // Only mention Fix-Its if the expression evaluator applied them.
 443   // Compiler errors refer to the final expression after applying Fix-It(s).
 444   if (!m_fixed_expression.empty() && target.GetEnableNotifyAboutFixIts()) {
 445     error_stream << "  Evaluated this expression after applying Fix-It(s):\n";
 446     error_stream << "    " << m_fixed_expression << "\n";
 447   }
 448
 449   if (result_valobj_sp) {
 450     Format format = m_format_options.GetFormat();
 451
 452     if (result_valobj_sp->GetError().Success()) {
 453       if (format != eFormatVoid) {
 454         if (format != eFormatDefault)
 455           result_valobj_sp->SetFormat(format);
 456
 457         if (m_varobj_options.elem_count > 0) {
 458           Status error(CanBeUsedForElementCountPrinting(*result_valobj_sp));
 459           if (error.Fail()) {
 460             result.AppendErrorWithFormat(
 461                 "expression cannot be used with --element-count %s\n",
 462                 error.AsCString(""));
 463             return false;
 464           }
 465         }
 466
 467         bool suppress_result =
 468             m_command_options.ShouldSuppressResult(m_varobj_options);
 469
 470         DumpValueObjectOptions options(m_varobj_options.GetAsDumpOptions(
 471             m_command_options.m_verbosity, format));
 472         options.SetHideRootName(suppress_result);
 473         options.SetVariableFormatDisplayLanguage(
 474             result_valobj_sp->GetPreferredDisplayLanguage());
 475
 476         result_valobj_sp->Dump(output_stream, options);
 477
 478         if (suppress_result)
 479           if (auto result_var_sp =
 480                   target.GetPersistentVariable(result_valobj_sp->GetName())) {
 481             auto language = result_valobj_sp->GetPreferredDisplayLanguage();
 482             if (auto *persistent_state =
 483                     target.GetPersistentExpressionStateForLanguage(language))
 484               persistent_state->RemovePersistentVariable(result_var_sp);
 485           }
 486         result.SetStatus(eReturnStatusSuccessFinishResult);
 487       }
 488     } else {
 489       if (result_valobj_sp->GetError().GetError() ==
 490           UserExpression::kNoResult) {
 491         if (format != eFormatVoid && GetDebugger().GetNotifyVoid()) {
 492           error_stream.PutCString("(void)\n");
 493         }
 494
 495         result.SetStatus(eReturnStatusSuccessFinishResult);
 496       } else {
 497         const char *error_cstr = result_valobj_sp->GetError().AsCString();
 498         if (error_cstr && error_cstr[0]) {
 499           const size_t error_cstr_len = strlen(error_cstr);
 500           const bool ends_with_newline = error_cstr[error_cstr_len - 1] == '\n';
 501           if (strstr(error_cstr, "error:") != error_cstr)
 502             error_stream.PutCString("error: ");
 503           error_stream.Write(error_cstr, error_cstr_len);
 504           if (!ends_with_newline)
 505             error_stream.EOL();
 506         } else {
 507           error_stream.PutCString("error: unknown error\n");
 508         }
 509
 510         result.SetStatus(eReturnStatusFailed);
 511       }
 512     }
 513   } else {
 514     error_stream.Printf("error: unknown error\n");
 515   }
 516
 517   return (success != eExpressionSetupError &&
 518           success != eExpressionParseError);
 519 }
 520
 521 void CommandObjectExpression::IOHandlerInputComplete(IOHandler &io_handler,
 522                                                      std::string &line) {
 523   io_handler.SetIsDone(true);
 524   StreamFileSP output_sp = io_handler.GetOutputStreamFileSP();
 525   StreamFileSP error_sp = io_handler.GetErrorStreamFileSP();
 526
 527   CommandReturnObject return_obj(
 528       GetCommandInterpreter().GetDebugger().GetUseColor());
 529   EvaluateExpression(line.c_str(), *output_sp, *error_sp, return_obj);
 530   if (output_sp)
 531     output_sp->Flush();
 532   if (error_sp)
 533     error_sp->Flush();
 534 }
 535
 536 bool CommandObjectExpression::IOHandlerIsInputComplete(IOHandler &io_handler,
 537                                                        StringList &lines) {
 538   // An empty lines is used to indicate the end of input
 539   const size_t num_lines = lines.GetSize();
 540   if (num_lines > 0 && lines[num_lines - 1].empty()) {
 541     // Remove the last empty line from "lines" so it doesn't appear in our
 542     // resulting input and return true to indicate we are done getting lines
 543     lines.PopBack();
 544     return true;
 545   }
 546   return false;
 547 }
 548
 549 void CommandObjectExpression::GetMultilineExpression() {
 550   m_expr_lines.clear();
 551   m_expr_line_count = 0;
 552
 553   Debugger &debugger = GetCommandInterpreter().GetDebugger();
 554   bool color_prompt = debugger.GetUseColor();
 555   const bool multiple_lines = true; // Get multiple lines
 556   IOHandlerSP io_handler_sp(
 557       new IOHandlerEditline(debugger, IOHandler::Type::Expression,
 558                             "lldb-expr", // Name of input reader for history
 559                             llvm::StringRef(), // No prompt
 560                             llvm::StringRef(), // Continuation prompt
 561                             multiple_lines, color_prompt,
 562                             1, // Show line numbers starting at 1
 563                             *this));
 564
 565   StreamFileSP output_sp = io_handler_sp->GetOutputStreamFileSP();
 566   if (output_sp) {
 567     output_sp->PutCString(
 568         "Enter expressions, then terminate with an empty line to evaluate:\n");
 569     output_sp->Flush();
 570   }
 571   debugger.RunIOHandlerAsync(io_handler_sp);
 572 }
 573
 574 static EvaluateExpressionOptions
 575 GetExprOptions(ExecutionContext &ctx,
 576                CommandObjectExpression::CommandOptions command_options) {
 577   command_options.OptionParsingStarting(&ctx);
 578
 579   // Default certain settings for REPL regardless of the global settings.
 580   command_options.unwind_on_error = false;
 581   command_options.ignore_breakpoints = false;
 582   command_options.debug = false;
 583
 584   EvaluateExpressionOptions expr_options;
 585   expr_options.SetUnwindOnError(command_options.unwind_on_error);
 586   expr_options.SetIgnoreBreakpoints(command_options.ignore_breakpoints);
 587   expr_options.SetTryAllThreads(command_options.try_all_threads);
 588
 589   if (command_options.timeout > 0)
 590     expr_options.SetTimeout(std::chrono::microseconds(command_options.timeout));
 591   else
 592     expr_options.SetTimeout(std::nullopt);
 593
 594   return expr_options;
 595 }
 596
 597 void CommandObjectExpression::DoExecute(llvm::StringRef command,
 598                                         CommandReturnObject &result) {
 599   m_fixed_expression.clear();
 600   auto exe_ctx = GetCommandInterpreter().GetExecutionContext();
 601   m_option_group.NotifyOptionParsingStarting(&exe_ctx);
 602
 603   if (command.empty()) {
 604     GetMultilineExpression();
 605     return;
 606   }
 607
 608   OptionsWithRaw args(command);
 609   llvm::StringRef expr = args.GetRawPart();
 610
 611   if (args.HasArgs()) {
 612     if (!ParseOptionsAndNotify(args.GetArgs(), result, m_option_group, exe_ctx))
 613       return;
 614
 615     if (m_repl_option.GetOptionValue().GetCurrentValue()) {
 616       Target &target = GetSelectedOrDummyTarget();
 617       // Drop into REPL
 618       m_expr_lines.clear();
 619       m_expr_line_count = 0;
 620
 621       Debugger &debugger = target.GetDebugger();
 622
 623       // Check if the LLDB command interpreter is sitting on top of a REPL
 624       // that launched it...
 625       if (debugger.CheckTopIOHandlerTypes(IOHandler::Type::CommandInterpreter,
 626                                           IOHandler::Type::REPL)) {
 627         // the LLDB command interpreter is sitting on top of a REPL that
 628         // launched it, so just say the command interpreter is done and
 629         // fall back to the existing REPL
 630         m_interpreter.GetIOHandler(false)->SetIsDone(true);
 631       } else {
 632         // We are launching the REPL on top of the current LLDB command
 633         // interpreter, so just push one
 634         bool initialize = false;
 635         Status repl_error;
 636         REPLSP repl_sp(target.GetREPL(repl_error, m_command_options.language,
 637                                        nullptr, false));
 638
 639         if (!repl_sp) {
 640           initialize = true;
 641           repl_sp = target.GetREPL(repl_error, m_command_options.language,
 642                                     nullptr, true);
 643           if (!repl_error.Success()) {
 644             result.SetError(repl_error);
 645             return;
 646           }
 647         }
 648
 649         if (repl_sp) {
 650           if (initialize) {
 651             repl_sp->SetEvaluateOptions(
 652                 GetExprOptions(exe_ctx, m_command_options));
 653             repl_sp->SetFormatOptions(m_format_options);
 654             repl_sp->SetValueObjectDisplayOptions(m_varobj_options);
 655           }
 656
 657           IOHandlerSP io_handler_sp(repl_sp->GetIOHandler());
 658           io_handler_sp->SetIsDone(false);
 659           debugger.RunIOHandlerAsync(io_handler_sp);
 660         } else {
 661           repl_error.SetErrorStringWithFormat(
 662               "Couldn't create a REPL for %s",
 663               Language::GetNameForLanguageType(m_command_options.language));
 664           result.SetError(repl_error);
 665           return;
 666         }
 667       }
 668     }
 669     // No expression following options
 670     else if (expr.empty()) {
 671       GetMultilineExpression();
 672       return;
 673     }
 674   }
 675
 676   Target &target = GetSelectedOrDummyTarget();
 677   if (EvaluateExpression(expr, result.GetOutputStream(),
 678                          result.GetErrorStream(), result)) {
 679
 680     if (!m_fixed_expression.empty() && target.GetEnableNotifyAboutFixIts()) {
 681       CommandHistory &history = m_interpreter.GetCommandHistory();
 682       // FIXME: Can we figure out what the user actually typed (e.g. some alias
 683       // for expr???)
 684       // If we can it would be nice to show that.
 685       std::string fixed_command("expression ");
 686       if (args.HasArgs()) {
 687         // Add in any options that might have been in the original command:
 688         fixed_command.append(std::string(args.GetArgStringWithDelimiter()));
 689         fixed_command.append(m_fixed_expression);
 690       } else
 691         fixed_command.append(m_fixed_expression);
 692       history.AppendString(fixed_command);
 693     }
 694     return;
 695   }
 696   result.SetStatus(eReturnStatusFailed);
 697 }