1 //===-- UserExpression.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 <cstdio> 10 #include <sys/types.h> 11 12 #include <cstdlib> 13 #include <map> 14 #include <string> 15 16 #include "lldb/Core/Module.h" 17 #include "lldb/Core/Progress.h" 18 #include "lldb/Expression/DiagnosticManager.h" 19 #include "lldb/Expression/ExpressionVariable.h" 20 #include "lldb/Expression/IRExecutionUnit.h" 21 #include "lldb/Expression/IRInterpreter.h" 22 #include "lldb/Expression/Materializer.h" 23 #include "lldb/Expression/UserExpression.h" 24 #include "lldb/Host/HostInfo.h" 25 #include "lldb/Symbol/Block.h" 26 #include "lldb/Symbol/Function.h" 27 #include "lldb/Symbol/ObjectFile.h" 28 #include "lldb/Symbol/SymbolVendor.h" 29 #include "lldb/Symbol/Type.h" 30 #include "lldb/Symbol/TypeSystem.h" 31 #include "lldb/Symbol/VariableList.h" 32 #include "lldb/Target/ExecutionContext.h" 33 #include "lldb/Target/Process.h" 34 #include "lldb/Target/StackFrame.h" 35 #include "lldb/Target/Target.h" 36 #include "lldb/Target/ThreadPlan.h" 37 #include "lldb/Target/ThreadPlanCallUserExpression.h" 38 #include "lldb/Utility/LLDBLog.h" 39 #include "lldb/Utility/Log.h" 40 #include "lldb/Utility/State.h" 41 #include "lldb/Utility/StreamString.h" 42 #include "lldb/ValueObject/ValueObjectConstResult.h" 43 #include "llvm/BinaryFormat/Dwarf.h" 44 45 using namespace lldb_private; 46 47 char UserExpression::ID; 48 49 UserExpression::UserExpression(ExecutionContextScope &exe_scope, 50 llvm::StringRef expr, llvm::StringRef prefix, 51 SourceLanguage language, ResultType desired_type, 52 const EvaluateExpressionOptions &options) 53 : Expression(exe_scope), m_expr_text(std::string(expr)), 54 m_expr_prefix(std::string(prefix)), m_language(language), 55 m_desired_type(desired_type), m_options(options) {} 56 57 UserExpression::~UserExpression() = default; 58 59 void UserExpression::InstallContext(ExecutionContext &exe_ctx) { 60 m_jit_process_wp = exe_ctx.GetProcessSP(); 61 62 lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP(); 63 64 if (frame_sp) 65 m_address = frame_sp->GetFrameCodeAddress(); 66 } 67 68 bool UserExpression::LockAndCheckContext(ExecutionContext &exe_ctx, 69 lldb::TargetSP &target_sp, 70 lldb::ProcessSP &process_sp, 71 lldb::StackFrameSP &frame_sp) { 72 lldb::ProcessSP expected_process_sp = m_jit_process_wp.lock(); 73 process_sp = exe_ctx.GetProcessSP(); 74 75 if (process_sp != expected_process_sp) 76 return false; 77 78 process_sp = exe_ctx.GetProcessSP(); 79 target_sp = exe_ctx.GetTargetSP(); 80 frame_sp = exe_ctx.GetFrameSP(); 81 82 if (m_address.IsValid()) { 83 if (!frame_sp) 84 return false; 85 return (Address::CompareLoadAddress(m_address, 86 frame_sp->GetFrameCodeAddress(), 87 target_sp.get()) == 0); 88 } 89 90 return true; 91 } 92 93 bool UserExpression::MatchesContext(ExecutionContext &exe_ctx) { 94 lldb::TargetSP target_sp; 95 lldb::ProcessSP process_sp; 96 lldb::StackFrameSP frame_sp; 97 98 return LockAndCheckContext(exe_ctx, target_sp, process_sp, frame_sp); 99 } 100 101 lldb::ValueObjectSP UserExpression::GetObjectPointerValueObject( 102 lldb::StackFrameSP frame_sp, llvm::StringRef object_name, Status &err) { 103 err.Clear(); 104 105 if (!frame_sp) { 106 err = Status::FromErrorStringWithFormatv( 107 "Couldn't load '{0}' because the context is incomplete", object_name); 108 return {}; 109 } 110 111 lldb::VariableSP var_sp; 112 lldb::ValueObjectSP valobj_sp; 113 114 return frame_sp->GetValueForVariableExpressionPath( 115 object_name, lldb::eNoDynamicValues, 116 StackFrame::eExpressionPathOptionCheckPtrVsMember | 117 StackFrame::eExpressionPathOptionsNoFragileObjcIvar | 118 StackFrame::eExpressionPathOptionsNoSyntheticChildren | 119 StackFrame::eExpressionPathOptionsNoSyntheticArrayRange, 120 var_sp, err); 121 } 122 123 lldb::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp, 124 llvm::StringRef object_name, 125 Status &err) { 126 auto valobj_sp = 127 GetObjectPointerValueObject(std::move(frame_sp), object_name, err); 128 129 if (!err.Success() || !valobj_sp.get()) 130 return LLDB_INVALID_ADDRESS; 131 132 lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS); 133 134 if (ret == LLDB_INVALID_ADDRESS) { 135 err = Status::FromErrorStringWithFormatv( 136 "Couldn't load '{0}' because its value couldn't be evaluated", 137 object_name); 138 return LLDB_INVALID_ADDRESS; 139 } 140 141 return ret; 142 } 143 144 lldb::ExpressionResults 145 UserExpression::Evaluate(ExecutionContext &exe_ctx, 146 const EvaluateExpressionOptions &options, 147 llvm::StringRef expr, llvm::StringRef prefix, 148 lldb::ValueObjectSP &result_valobj_sp, 149 std::string *fixed_expression, ValueObject *ctx_obj) { 150 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step)); 151 auto set_error = [&](Status error) { 152 result_valobj_sp = ValueObjectConstResult::Create( 153 exe_ctx.GetBestExecutionContextScope(), std::move(error)); 154 }; 155 156 if (ctx_obj) { 157 static unsigned const ctx_type_mask = lldb::TypeFlags::eTypeIsClass | 158 lldb::TypeFlags::eTypeIsStructUnion | 159 lldb::TypeFlags::eTypeIsReference; 160 if (!(ctx_obj->GetTypeInfo() & ctx_type_mask)) { 161 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 162 "an invalid type, can't run expressions."); 163 set_error(Status("a context object of an invalid type passed")); 164 return lldb::eExpressionSetupError; 165 } 166 } 167 168 if (ctx_obj && ctx_obj->GetTypeInfo() & lldb::TypeFlags::eTypeIsReference) { 169 Status error; 170 lldb::ValueObjectSP deref_ctx_sp = ctx_obj->Dereference(error); 171 if (!error.Success()) { 172 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 173 "a reference type that can't be dereferenced, can't run " 174 "expressions."); 175 set_error(Status( 176 "passed context object of an reference type cannot be deferenced")); 177 return lldb::eExpressionSetupError; 178 } 179 180 ctx_obj = deref_ctx_sp.get(); 181 } 182 183 lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy(); 184 SourceLanguage language = options.GetLanguage(); 185 const ResultType desired_type = options.DoesCoerceToId() 186 ? UserExpression::eResultTypeId 187 : UserExpression::eResultTypeAny; 188 Target *target = exe_ctx.GetTargetPtr(); 189 if (!target) { 190 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a NULL target, can't " 191 "run expressions."); 192 set_error(Status("expression passed a null target")); 193 return lldb::eExpressionSetupError; 194 } 195 196 Process *process = exe_ctx.GetProcessPtr(); 197 198 if (!process && execution_policy == eExecutionPolicyAlways) { 199 LLDB_LOG(log, "== [UserExpression::Evaluate] No process, but the policy is " 200 "eExecutionPolicyAlways"); 201 202 set_error(Status("expression needed to run but couldn't: no process")); 203 204 return lldb::eExpressionSetupError; 205 } 206 207 // Since we might need to allocate memory, we need to be stopped to run 208 // an expression. 209 if (process && process->GetState() != lldb::eStateStopped) { 210 set_error(Status::FromErrorStringWithFormatv( 211 "unable to evaluate expression while the process is {0}: the process " 212 "must be stopped because the expression might require allocating " 213 "memory.", 214 StateAsCString(process->GetState()))); 215 return lldb::eExpressionSetupError; 216 } 217 218 // Explicitly force the IR interpreter to evaluate the expression when the 219 // there is no process that supports running the expression for us. Don't 220 // change the execution policy if we have the special top-level policy that 221 // doesn't contain any expression and there is nothing to interpret. 222 if (execution_policy != eExecutionPolicyTopLevel && 223 (process == nullptr || !process->CanJIT())) 224 execution_policy = eExecutionPolicyNever; 225 226 // We need to set the expression execution thread here, turns out parse can 227 // call functions in the process of looking up symbols, which will escape the 228 // context set by exe_ctx passed to Execute. 229 lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP(); 230 ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher( 231 thread_sp); 232 233 llvm::StringRef full_prefix; 234 llvm::StringRef option_prefix(options.GetPrefix()); 235 std::string full_prefix_storage; 236 if (!prefix.empty() && !option_prefix.empty()) { 237 full_prefix_storage = std::string(prefix); 238 full_prefix_storage.append(std::string(option_prefix)); 239 full_prefix = full_prefix_storage; 240 } else if (!prefix.empty()) 241 full_prefix = prefix; 242 else 243 full_prefix = option_prefix; 244 245 // If the language was not specified in the expression command, set it to the 246 // language in the target's properties if specified, else default to the 247 // langage for the frame. 248 if (!language) { 249 if (target->GetLanguage() != lldb::eLanguageTypeUnknown) 250 language = target->GetLanguage(); 251 else if (StackFrame *frame = exe_ctx.GetFramePtr()) 252 language = frame->GetLanguage(); 253 } 254 255 Status error; 256 lldb::UserExpressionSP user_expression_sp( 257 target->GetUserExpressionForLanguage( 258 expr, full_prefix, language, desired_type, options, ctx_obj, error)); 259 if (error.Fail() || !user_expression_sp) { 260 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==", 261 error.AsCString()); 262 set_error(std::move(error)); 263 return lldb::eExpressionSetupError; 264 } 265 266 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==", 267 expr.str()); 268 269 const bool keep_expression_in_memory = true; 270 const bool generate_debug_info = options.GetGenerateDebugInfo(); 271 272 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) { 273 set_error(Status("expression interrupted by callback before parse")); 274 return lldb::eExpressionInterrupted; 275 } 276 277 DiagnosticManager diagnostic_manager; 278 279 bool parse_success = 280 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy, 281 keep_expression_in_memory, generate_debug_info); 282 283 // Calculate the fixed expression always, since we need it for errors. 284 std::string tmp_fixed_expression; 285 if (fixed_expression == nullptr) 286 fixed_expression = &tmp_fixed_expression; 287 288 *fixed_expression = user_expression_sp->GetFixedText().str(); 289 lldb::ExpressionResults execution_results = lldb::eExpressionSetupError; 290 291 // If there is a fixed expression, try to parse it: 292 if (!parse_success) { 293 // Delete the expression that failed to parse before attempting to parse 294 // the next expression. 295 user_expression_sp.reset(); 296 297 execution_results = lldb::eExpressionParseError; 298 if (!fixed_expression->empty() && options.GetAutoApplyFixIts()) { 299 const uint64_t max_fix_retries = options.GetRetriesWithFixIts(); 300 for (uint64_t i = 0; i < max_fix_retries; ++i) { 301 // Try parsing the fixed expression. 302 lldb::UserExpressionSP fixed_expression_sp( 303 target->GetUserExpressionForLanguage( 304 fixed_expression->c_str(), full_prefix, language, desired_type, 305 options, ctx_obj, error)); 306 if (!fixed_expression_sp) 307 break; 308 DiagnosticManager fixed_diagnostic_manager; 309 parse_success = fixed_expression_sp->Parse( 310 fixed_diagnostic_manager, exe_ctx, execution_policy, 311 keep_expression_in_memory, generate_debug_info); 312 if (parse_success) { 313 diagnostic_manager.Clear(); 314 user_expression_sp = fixed_expression_sp; 315 break; 316 } 317 // The fixed expression also didn't parse. Let's check for any new 318 // fixits we could try. 319 if (!fixed_expression_sp->GetFixedText().empty()) { 320 *fixed_expression = fixed_expression_sp->GetFixedText().str(); 321 } else { 322 // Fixed expression didn't compile without a fixit, don't retry and 323 // don't tell the user about it. 324 fixed_expression->clear(); 325 break; 326 } 327 } 328 } 329 330 if (!parse_success) { 331 if (target->GetEnableNotifyAboutFixIts() && fixed_expression && 332 !fixed_expression->empty()) { 333 std::string fixit = 334 "fixed expression suggested:\n " + *fixed_expression; 335 diagnostic_manager.AddDiagnostic(fixit, lldb::eSeverityInfo, 336 eDiagnosticOriginLLDB); 337 } 338 if (diagnostic_manager.Diagnostics().empty()) 339 error = Status::FromError(llvm::make_error<ExpressionError>( 340 execution_results, 341 "expression failed to parse (no further compiler diagnostics)")); 342 else 343 error = 344 Status::FromError(diagnostic_manager.GetAsError(execution_results)); 345 } 346 } 347 348 if (parse_success) { 349 lldb::ExpressionVariableSP expr_result; 350 351 if (execution_policy == eExecutionPolicyNever && 352 !user_expression_sp->CanInterpret()) { 353 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 354 "is not constant =="); 355 356 if (diagnostic_manager.Diagnostics().empty()) 357 error = Status::FromError(llvm::make_error<ExpressionError>( 358 lldb::eExpressionSetupError, 359 "expression needed to run but couldn't")); 360 } else if (execution_policy == eExecutionPolicyTopLevel) { 361 set_error(Status(UserExpression::kNoResult, lldb::eErrorTypeGeneric)); 362 return lldb::eExpressionCompleted; 363 } else { 364 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) { 365 set_error(Status::FromError(llvm::make_error<ExpressionError>( 366 lldb::eExpressionInterrupted, 367 "expression interrupted by callback before execution"))); 368 return lldb::eExpressionInterrupted; 369 } 370 371 diagnostic_manager.Clear(); 372 373 LLDB_LOG(log, "== [UserExpression::Evaluate] Executing expression =="); 374 375 execution_results = 376 user_expression_sp->Execute(diagnostic_manager, exe_ctx, options, 377 user_expression_sp, expr_result); 378 379 if (execution_results != lldb::eExpressionCompleted) { 380 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 381 "abnormally =="); 382 383 if (diagnostic_manager.Diagnostics().empty()) 384 error = Status::FromError(llvm::make_error<ExpressionError>( 385 execution_results, 386 "expression failed to execute, unknown error")); 387 else 388 error = Status::FromError( 389 diagnostic_manager.GetAsError(execution_results)); 390 } else { 391 if (expr_result) { 392 result_valobj_sp = expr_result->GetValueObject(); 393 result_valobj_sp->SetPreferredDisplayLanguage( 394 language.AsLanguageType()); 395 396 LLDB_LOG(log, 397 "== [UserExpression::Evaluate] Execution completed " 398 "normally with result {0} ==", 399 result_valobj_sp->GetValueAsCString()); 400 } else { 401 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 402 "normally with no result =="); 403 404 error = Status(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 405 } 406 } 407 } 408 } 409 410 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) { 411 set_error(Status::FromError(llvm::make_error<ExpressionError>( 412 lldb::eExpressionInterrupted, 413 "expression interrupted by callback after complete"))); 414 return lldb::eExpressionInterrupted; 415 } 416 417 if (error.Fail()) 418 set_error(std::move(error)); 419 return execution_results; 420 } 421 422 lldb::ExpressionResults 423 UserExpression::Execute(DiagnosticManager &diagnostic_manager, 424 ExecutionContext &exe_ctx, 425 const EvaluateExpressionOptions &options, 426 lldb::UserExpressionSP &shared_ptr_to_me, 427 lldb::ExpressionVariableSP &result_var) { 428 Debugger *debugger = 429 exe_ctx.GetTargetPtr() ? &exe_ctx.GetTargetPtr()->GetDebugger() : nullptr; 430 std::string details; 431 if (m_options.IsForUtilityExpr()) 432 details = "LLDB utility"; 433 else if (m_expr_text.size() > 15) 434 details = m_expr_text.substr(0, 14) + "…"; 435 else 436 details = m_expr_text; 437 438 Progress progress("Running expression", details, {}, debugger); 439 440 lldb::ExpressionResults expr_result = DoExecute( 441 diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var); 442 Target *target = exe_ctx.GetTargetPtr(); 443 if (options.GetSuppressPersistentResult() && result_var && target) { 444 if (auto *persistent_state = 445 target->GetPersistentExpressionStateForLanguage( 446 m_language.AsLanguageType())) 447 persistent_state->RemovePersistentVariable(result_var); 448 } 449 return expr_result; 450 } 451