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/StreamFile.h" 18 #include "lldb/Core/ValueObjectConstResult.h" 19 #include "lldb/Expression/DiagnosticManager.h" 20 #include "lldb/Expression/ExpressionVariable.h" 21 #include "lldb/Expression/IRExecutionUnit.h" 22 #include "lldb/Expression/IRInterpreter.h" 23 #include "lldb/Expression/Materializer.h" 24 #include "lldb/Expression/UserExpression.h" 25 #include "lldb/Host/HostInfo.h" 26 #include "lldb/Symbol/Block.h" 27 #include "lldb/Symbol/Function.h" 28 #include "lldb/Symbol/ObjectFile.h" 29 #include "lldb/Symbol/SymbolVendor.h" 30 #include "lldb/Symbol/Type.h" 31 #include "lldb/Symbol/TypeSystem.h" 32 #include "lldb/Symbol/VariableList.h" 33 #include "lldb/Target/ExecutionContext.h" 34 #include "lldb/Target/Process.h" 35 #include "lldb/Target/StackFrame.h" 36 #include "lldb/Target/Target.h" 37 #include "lldb/Target/ThreadPlan.h" 38 #include "lldb/Target/ThreadPlanCallUserExpression.h" 39 #include "lldb/Utility/ConstString.h" 40 #include "lldb/Utility/LLDBLog.h" 41 #include "lldb/Utility/Log.h" 42 #include "lldb/Utility/State.h" 43 #include "lldb/Utility/StreamString.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 lldb::LanguageType language, 52 ResultType desired_type, 53 const EvaluateExpressionOptions &options) 54 : Expression(exe_scope), m_expr_text(std::string(expr)), 55 m_expr_prefix(std::string(prefix)), m_language(language), 56 m_desired_type(desired_type), m_options(options) {} 57 58 UserExpression::~UserExpression() = default; 59 60 void UserExpression::InstallContext(ExecutionContext &exe_ctx) { 61 m_jit_process_wp = exe_ctx.GetProcessSP(); 62 63 lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP(); 64 65 if (frame_sp) 66 m_address = frame_sp->GetFrameCodeAddress(); 67 } 68 69 bool UserExpression::LockAndCheckContext(ExecutionContext &exe_ctx, 70 lldb::TargetSP &target_sp, 71 lldb::ProcessSP &process_sp, 72 lldb::StackFrameSP &frame_sp) { 73 lldb::ProcessSP expected_process_sp = m_jit_process_wp.lock(); 74 process_sp = exe_ctx.GetProcessSP(); 75 76 if (process_sp != expected_process_sp) 77 return false; 78 79 process_sp = exe_ctx.GetProcessSP(); 80 target_sp = exe_ctx.GetTargetSP(); 81 frame_sp = exe_ctx.GetFrameSP(); 82 83 if (m_address.IsValid()) { 84 if (!frame_sp) 85 return false; 86 return (Address::CompareLoadAddress(m_address, 87 frame_sp->GetFrameCodeAddress(), 88 target_sp.get()) == 0); 89 } 90 91 return true; 92 } 93 94 bool UserExpression::MatchesContext(ExecutionContext &exe_ctx) { 95 lldb::TargetSP target_sp; 96 lldb::ProcessSP process_sp; 97 lldb::StackFrameSP frame_sp; 98 99 return LockAndCheckContext(exe_ctx, target_sp, process_sp, frame_sp); 100 } 101 102 lldb::ValueObjectSP UserExpression::GetObjectPointerValueObject( 103 lldb::StackFrameSP frame_sp, ConstString const &object_name, Status &err) { 104 err.Clear(); 105 106 if (!frame_sp) { 107 err.SetErrorStringWithFormat( 108 "Couldn't load '%s' because the context is incomplete", 109 object_name.AsCString()); 110 return {}; 111 } 112 113 lldb::VariableSP var_sp; 114 lldb::ValueObjectSP valobj_sp; 115 116 return frame_sp->GetValueForVariableExpressionPath( 117 object_name.GetStringRef(), lldb::eNoDynamicValues, 118 StackFrame::eExpressionPathOptionCheckPtrVsMember | 119 StackFrame::eExpressionPathOptionsNoFragileObjcIvar | 120 StackFrame::eExpressionPathOptionsNoSyntheticChildren | 121 StackFrame::eExpressionPathOptionsNoSyntheticArrayRange, 122 var_sp, err); 123 } 124 125 lldb::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp, 126 ConstString &object_name, 127 Status &err) { 128 auto valobj_sp = 129 GetObjectPointerValueObject(std::move(frame_sp), object_name, err); 130 131 if (!err.Success() || !valobj_sp.get()) 132 return LLDB_INVALID_ADDRESS; 133 134 lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS); 135 136 if (ret == LLDB_INVALID_ADDRESS) { 137 err.SetErrorStringWithFormat( 138 "Couldn't load '%s' because its value couldn't be evaluated", 139 object_name.AsCString()); 140 return LLDB_INVALID_ADDRESS; 141 } 142 143 return ret; 144 } 145 146 lldb::ExpressionResults 147 UserExpression::Evaluate(ExecutionContext &exe_ctx, 148 const EvaluateExpressionOptions &options, 149 llvm::StringRef expr, llvm::StringRef prefix, 150 lldb::ValueObjectSP &result_valobj_sp, Status &error, 151 std::string *fixed_expression, ValueObject *ctx_obj) { 152 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step)); 153 154 if (ctx_obj) { 155 static unsigned const ctx_type_mask = lldb::TypeFlags::eTypeIsClass | 156 lldb::TypeFlags::eTypeIsStructUnion | 157 lldb::TypeFlags::eTypeIsReference; 158 if (!(ctx_obj->GetTypeInfo() & ctx_type_mask)) { 159 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 160 "an invalid type, can't run expressions."); 161 error.SetErrorString("a context object of an invalid type passed"); 162 return lldb::eExpressionSetupError; 163 } 164 } 165 166 if (ctx_obj && ctx_obj->GetTypeInfo() & lldb::TypeFlags::eTypeIsReference) { 167 Status error; 168 lldb::ValueObjectSP deref_ctx_sp = ctx_obj->Dereference(error); 169 if (!error.Success()) { 170 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 171 "a reference type that can't be dereferenced, can't run " 172 "expressions."); 173 error.SetErrorString( 174 "passed context object of an reference type cannot be deferenced"); 175 return lldb::eExpressionSetupError; 176 } 177 178 ctx_obj = deref_ctx_sp.get(); 179 } 180 181 lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy(); 182 lldb::LanguageType language = options.GetLanguage(); 183 const ResultType desired_type = options.DoesCoerceToId() 184 ? UserExpression::eResultTypeId 185 : UserExpression::eResultTypeAny; 186 lldb::ExpressionResults execution_results = lldb::eExpressionSetupError; 187 188 Target *target = exe_ctx.GetTargetPtr(); 189 if (!target) { 190 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a NULL target, can't " 191 "run expressions."); 192 error.SetErrorString("expression passed a null target"); 193 return lldb::eExpressionSetupError; 194 } 195 196 Process *process = exe_ctx.GetProcessPtr(); 197 198 if (process == nullptr && execution_policy == eExecutionPolicyAlways) { 199 LLDB_LOG(log, "== [UserExpression::Evaluate] No process, but the policy is " 200 "eExecutionPolicyAlways"); 201 202 error.SetErrorString("expression needed to run but couldn't: no process"); 203 204 return execution_results; 205 } 206 207 // Since we might need to allocate memory, we need to be stopped to run 208 // an expression. 209 if (process != nullptr && process->GetState() != lldb::eStateStopped) { 210 error.SetErrorStringWithFormatv( 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 execution_results; 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 == lldb::eLanguageTypeUnknown) { 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 lldb::UserExpressionSP user_expression_sp( 256 target->GetUserExpressionForLanguage(expr, full_prefix, language, 257 desired_type, options, ctx_obj, 258 error)); 259 if (error.Fail()) { 260 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==", 261 error.AsCString()); 262 return lldb::eExpressionSetupError; 263 } 264 265 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==", 266 expr.str()); 267 268 const bool keep_expression_in_memory = true; 269 const bool generate_debug_info = options.GetGenerateDebugInfo(); 270 271 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) { 272 error.SetErrorString("expression interrupted by callback before parse"); 273 result_valobj_sp = ValueObjectConstResult::Create( 274 exe_ctx.GetBestExecutionContextScope(), error); 275 return lldb::eExpressionInterrupted; 276 } 277 278 DiagnosticManager diagnostic_manager; 279 280 bool parse_success = 281 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy, 282 keep_expression_in_memory, generate_debug_info); 283 284 // Calculate the fixed expression always, since we need it for errors. 285 std::string tmp_fixed_expression; 286 if (fixed_expression == nullptr) 287 fixed_expression = &tmp_fixed_expression; 288 289 *fixed_expression = user_expression_sp->GetFixedText().str(); 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 DiagnosticManager fixed_diagnostic_manager; 307 parse_success = fixed_expression_sp->Parse( 308 fixed_diagnostic_manager, exe_ctx, execution_policy, 309 keep_expression_in_memory, generate_debug_info); 310 if (parse_success) { 311 diagnostic_manager.Clear(); 312 user_expression_sp = fixed_expression_sp; 313 break; 314 } else { 315 // The fixed expression also didn't parse. Let's check for any new 316 // Fix-Its we could try. 317 if (!fixed_expression_sp->GetFixedText().empty()) { 318 *fixed_expression = fixed_expression_sp->GetFixedText().str(); 319 } else { 320 // Fixed expression didn't compile without a fixit, don't retry and 321 // don't tell the user about it. 322 fixed_expression->clear(); 323 break; 324 } 325 } 326 } 327 } 328 329 if (!parse_success) { 330 std::string msg; 331 { 332 llvm::raw_string_ostream os(msg); 333 if (!diagnostic_manager.Diagnostics().empty()) 334 os << diagnostic_manager.GetString(); 335 else 336 os << "expression failed to parse (no further compiler diagnostics)"; 337 if (target->GetEnableNotifyAboutFixIts() && fixed_expression && 338 !fixed_expression->empty()) 339 os << "\nfixed expression suggested:\n " << *fixed_expression; 340 } 341 error.SetExpressionError(execution_results, msg.c_str()); 342 } 343 } 344 345 if (parse_success) { 346 lldb::ExpressionVariableSP expr_result; 347 348 if (execution_policy == eExecutionPolicyNever && 349 !user_expression_sp->CanInterpret()) { 350 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 351 "is not constant =="); 352 353 if (!diagnostic_manager.Diagnostics().size()) 354 error.SetExpressionError(lldb::eExpressionSetupError, 355 "expression needed to run but couldn't"); 356 } else if (execution_policy == eExecutionPolicyTopLevel) { 357 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 358 return lldb::eExpressionCompleted; 359 } else { 360 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) { 361 error.SetExpressionError( 362 lldb::eExpressionInterrupted, 363 "expression interrupted by callback before execution"); 364 result_valobj_sp = ValueObjectConstResult::Create( 365 exe_ctx.GetBestExecutionContextScope(), error); 366 return lldb::eExpressionInterrupted; 367 } 368 369 diagnostic_manager.Clear(); 370 371 LLDB_LOG(log, "== [UserExpression::Evaluate] Executing expression =="); 372 373 execution_results = 374 user_expression_sp->Execute(diagnostic_manager, exe_ctx, options, 375 user_expression_sp, expr_result); 376 377 if (execution_results != lldb::eExpressionCompleted) { 378 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 379 "abnormally =="); 380 381 if (!diagnostic_manager.Diagnostics().size()) 382 error.SetExpressionError( 383 execution_results, "expression failed to execute, unknown error"); 384 else 385 error.SetExpressionError(execution_results, 386 diagnostic_manager.GetString().c_str()); 387 } else { 388 if (expr_result) { 389 result_valobj_sp = expr_result->GetValueObject(); 390 result_valobj_sp->SetPreferredDisplayLanguage(language); 391 392 LLDB_LOG(log, 393 "== [UserExpression::Evaluate] Execution completed " 394 "normally with result {0} ==", 395 result_valobj_sp->GetValueAsCString()); 396 } else { 397 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 398 "normally with no result =="); 399 400 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 401 } 402 } 403 } 404 } 405 406 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) { 407 error.SetExpressionError( 408 lldb::eExpressionInterrupted, 409 "expression interrupted by callback after complete"); 410 return lldb::eExpressionInterrupted; 411 } 412 413 if (result_valobj_sp.get() == nullptr) { 414 result_valobj_sp = ValueObjectConstResult::Create( 415 exe_ctx.GetBestExecutionContextScope(), error); 416 } 417 418 return execution_results; 419 } 420 421 lldb::ExpressionResults 422 UserExpression::Execute(DiagnosticManager &diagnostic_manager, 423 ExecutionContext &exe_ctx, 424 const EvaluateExpressionOptions &options, 425 lldb::UserExpressionSP &shared_ptr_to_me, 426 lldb::ExpressionVariableSP &result_var) { 427 lldb::ExpressionResults expr_result = DoExecute( 428 diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var); 429 Target *target = exe_ctx.GetTargetPtr(); 430 if (options.GetSuppressPersistentResult() && result_var && target) { 431 if (auto *persistent_state = 432 target->GetPersistentExpressionStateForLanguage(m_language)) 433 persistent_state->RemovePersistentVariable(result_var); 434 } 435 return expr_result; 436 } 437