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/StreamString.h" 43 44 using namespace lldb_private; 45 46 char UserExpression::ID; 47 48 UserExpression::UserExpression(ExecutionContextScope &exe_scope, 49 llvm::StringRef expr, llvm::StringRef prefix, 50 lldb::LanguageType language, 51 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, ConstString const &object_name, Status &err) { 103 err.Clear(); 104 105 if (!frame_sp) { 106 err.SetErrorStringWithFormat( 107 "Couldn't load '%s' because the context is incomplete", 108 object_name.AsCString()); 109 return {}; 110 } 111 112 lldb::VariableSP var_sp; 113 lldb::ValueObjectSP valobj_sp; 114 115 return frame_sp->GetValueForVariableExpressionPath( 116 object_name.GetStringRef(), lldb::eNoDynamicValues, 117 StackFrame::eExpressionPathOptionCheckPtrVsMember | 118 StackFrame::eExpressionPathOptionsNoFragileObjcIvar | 119 StackFrame::eExpressionPathOptionsNoSyntheticChildren | 120 StackFrame::eExpressionPathOptionsNoSyntheticArrayRange, 121 var_sp, err); 122 } 123 124 lldb::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp, 125 ConstString &object_name, 126 Status &err) { 127 auto valobj_sp = 128 GetObjectPointerValueObject(std::move(frame_sp), object_name, err); 129 130 if (!err.Success() || !valobj_sp.get()) 131 return LLDB_INVALID_ADDRESS; 132 133 lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS); 134 135 if (ret == LLDB_INVALID_ADDRESS) { 136 err.SetErrorStringWithFormat( 137 "Couldn't load '%s' because its value couldn't be evaluated", 138 object_name.AsCString()); 139 return LLDB_INVALID_ADDRESS; 140 } 141 142 return ret; 143 } 144 145 lldb::ExpressionResults 146 UserExpression::Evaluate(ExecutionContext &exe_ctx, 147 const EvaluateExpressionOptions &options, 148 llvm::StringRef expr, llvm::StringRef prefix, 149 lldb::ValueObjectSP &result_valobj_sp, Status &error, 150 std::string *fixed_expression, ValueObject *ctx_obj) { 151 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step)); 152 153 if (ctx_obj) { 154 static unsigned const ctx_type_mask = lldb::TypeFlags::eTypeIsClass | 155 lldb::TypeFlags::eTypeIsStructUnion | 156 lldb::TypeFlags::eTypeIsReference; 157 if (!(ctx_obj->GetTypeInfo() & ctx_type_mask)) { 158 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 159 "an invalid type, can't run expressions."); 160 error.SetErrorString("a context object of an invalid type passed"); 161 return lldb::eExpressionSetupError; 162 } 163 } 164 165 if (ctx_obj && ctx_obj->GetTypeInfo() & lldb::TypeFlags::eTypeIsReference) { 166 Status error; 167 lldb::ValueObjectSP deref_ctx_sp = ctx_obj->Dereference(error); 168 if (!error.Success()) { 169 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 170 "a reference type that can't be dereferenced, can't run " 171 "expressions."); 172 error.SetErrorString( 173 "passed context object of an reference type cannot be deferenced"); 174 return lldb::eExpressionSetupError; 175 } 176 177 ctx_obj = deref_ctx_sp.get(); 178 } 179 180 lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy(); 181 lldb::LanguageType language = options.GetLanguage(); 182 const ResultType desired_type = options.DoesCoerceToId() 183 ? UserExpression::eResultTypeId 184 : UserExpression::eResultTypeAny; 185 lldb::ExpressionResults execution_results = lldb::eExpressionSetupError; 186 187 Target *target = exe_ctx.GetTargetPtr(); 188 if (!target) { 189 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a NULL target, can't " 190 "run expressions."); 191 error.SetErrorString("expression passed a null target"); 192 return lldb::eExpressionSetupError; 193 } 194 195 Process *process = exe_ctx.GetProcessPtr(); 196 197 if (process == nullptr && execution_policy == eExecutionPolicyAlways) { 198 LLDB_LOG(log, "== [UserExpression::Evaluate] No process, but the policy is " 199 "eExecutionPolicyAlways"); 200 201 error.SetErrorString("expression needed to run but couldn't: no process"); 202 203 return execution_results; 204 } 205 // Since we might need to call allocate memory and maybe call code to make 206 // the caller, we need to be stopped. 207 if (process != nullptr && process->GetState() != lldb::eStateStopped) { 208 error.SetErrorString("Can't make a function caller while the process is " 209 "running"); 210 return execution_results; 211 } 212 213 214 // Explicitly force the IR interpreter to evaluate the expression when the 215 // there is no process that supports running the expression for us. Don't 216 // change the execution policy if we have the special top-level policy that 217 // doesn't contain any expression and there is nothing to interpret. 218 if (execution_policy != eExecutionPolicyTopLevel && 219 (process == nullptr || !process->CanJIT())) 220 execution_policy = eExecutionPolicyNever; 221 222 // We need to set the expression execution thread here, turns out parse can 223 // call functions in the process of looking up symbols, which will escape the 224 // context set by exe_ctx passed to Execute. 225 lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP(); 226 ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher( 227 thread_sp); 228 229 llvm::StringRef full_prefix; 230 llvm::StringRef option_prefix(options.GetPrefix()); 231 std::string full_prefix_storage; 232 if (!prefix.empty() && !option_prefix.empty()) { 233 full_prefix_storage = std::string(prefix); 234 full_prefix_storage.append(std::string(option_prefix)); 235 full_prefix = full_prefix_storage; 236 } else if (!prefix.empty()) 237 full_prefix = prefix; 238 else 239 full_prefix = option_prefix; 240 241 // If the language was not specified in the expression command, set it to the 242 // language in the target's properties if specified, else default to the 243 // langage for the frame. 244 if (language == lldb::eLanguageTypeUnknown) { 245 if (target->GetLanguage() != lldb::eLanguageTypeUnknown) 246 language = target->GetLanguage(); 247 else if (StackFrame *frame = exe_ctx.GetFramePtr()) 248 language = frame->GetLanguage(); 249 } 250 251 lldb::UserExpressionSP user_expression_sp( 252 target->GetUserExpressionForLanguage(expr, full_prefix, language, 253 desired_type, options, ctx_obj, 254 error)); 255 if (error.Fail()) { 256 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==", 257 error.AsCString()); 258 return lldb::eExpressionSetupError; 259 } 260 261 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==", 262 expr.str()); 263 264 const bool keep_expression_in_memory = true; 265 const bool generate_debug_info = options.GetGenerateDebugInfo(); 266 267 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) { 268 error.SetErrorString("expression interrupted by callback before parse"); 269 result_valobj_sp = ValueObjectConstResult::Create( 270 exe_ctx.GetBestExecutionContextScope(), error); 271 return lldb::eExpressionInterrupted; 272 } 273 274 DiagnosticManager diagnostic_manager; 275 276 bool parse_success = 277 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy, 278 keep_expression_in_memory, generate_debug_info); 279 280 // Calculate the fixed expression always, since we need it for errors. 281 std::string tmp_fixed_expression; 282 if (fixed_expression == nullptr) 283 fixed_expression = &tmp_fixed_expression; 284 285 *fixed_expression = user_expression_sp->GetFixedText().str(); 286 287 // If there is a fixed expression, try to parse it: 288 if (!parse_success) { 289 // Delete the expression that failed to parse before attempting to parse 290 // the next expression. 291 user_expression_sp.reset(); 292 293 execution_results = lldb::eExpressionParseError; 294 if (!fixed_expression->empty() && options.GetAutoApplyFixIts()) { 295 const uint64_t max_fix_retries = options.GetRetriesWithFixIts(); 296 for (uint64_t i = 0; i < max_fix_retries; ++i) { 297 // Try parsing the fixed expression. 298 lldb::UserExpressionSP fixed_expression_sp( 299 target->GetUserExpressionForLanguage( 300 fixed_expression->c_str(), full_prefix, language, desired_type, 301 options, ctx_obj, error)); 302 DiagnosticManager fixed_diagnostic_manager; 303 parse_success = fixed_expression_sp->Parse( 304 fixed_diagnostic_manager, exe_ctx, execution_policy, 305 keep_expression_in_memory, generate_debug_info); 306 if (parse_success) { 307 diagnostic_manager.Clear(); 308 user_expression_sp = fixed_expression_sp; 309 break; 310 } else { 311 // The fixed expression also didn't parse. Let's check for any new 312 // Fix-Its we could try. 313 if (!fixed_expression_sp->GetFixedText().empty()) { 314 *fixed_expression = fixed_expression_sp->GetFixedText().str(); 315 } else { 316 // Fixed expression didn't compile without a fixit, don't retry and 317 // don't tell the user about it. 318 fixed_expression->clear(); 319 break; 320 } 321 } 322 } 323 } 324 325 if (!parse_success) { 326 std::string msg; 327 { 328 llvm::raw_string_ostream os(msg); 329 os << "expression failed to parse:\n"; 330 if (!diagnostic_manager.Diagnostics().empty()) 331 os << diagnostic_manager.GetString(); 332 else 333 os << "unknown error"; 334 if (target->GetEnableNotifyAboutFixIts() && fixed_expression && 335 !fixed_expression->empty()) 336 os << "\nfixed expression suggested:\n " << *fixed_expression; 337 } 338 error.SetExpressionError(execution_results, msg.c_str()); 339 } 340 } 341 342 if (parse_success) { 343 lldb::ExpressionVariableSP expr_result; 344 345 if (execution_policy == eExecutionPolicyNever && 346 !user_expression_sp->CanInterpret()) { 347 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 348 "is not constant =="); 349 350 if (!diagnostic_manager.Diagnostics().size()) 351 error.SetExpressionError(lldb::eExpressionSetupError, 352 "expression needed to run but couldn't"); 353 } else if (execution_policy == eExecutionPolicyTopLevel) { 354 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 355 return lldb::eExpressionCompleted; 356 } else { 357 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) { 358 error.SetExpressionError( 359 lldb::eExpressionInterrupted, 360 "expression interrupted by callback before execution"); 361 result_valobj_sp = ValueObjectConstResult::Create( 362 exe_ctx.GetBestExecutionContextScope(), error); 363 return lldb::eExpressionInterrupted; 364 } 365 366 diagnostic_manager.Clear(); 367 368 LLDB_LOG(log, "== [UserExpression::Evaluate] Executing expression =="); 369 370 execution_results = 371 user_expression_sp->Execute(diagnostic_manager, exe_ctx, options, 372 user_expression_sp, expr_result); 373 374 if (execution_results != lldb::eExpressionCompleted) { 375 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 376 "abnormally =="); 377 378 if (!diagnostic_manager.Diagnostics().size()) 379 error.SetExpressionError( 380 execution_results, "expression failed to execute, unknown error"); 381 else 382 error.SetExpressionError(execution_results, 383 diagnostic_manager.GetString().c_str()); 384 } else { 385 if (expr_result) { 386 result_valobj_sp = expr_result->GetValueObject(); 387 result_valobj_sp->SetPreferredDisplayLanguage(language); 388 389 LLDB_LOG(log, 390 "== [UserExpression::Evaluate] Execution completed " 391 "normally with result {0} ==", 392 result_valobj_sp->GetValueAsCString()); 393 } else { 394 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 395 "normally with no result =="); 396 397 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 398 } 399 } 400 } 401 } 402 403 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) { 404 error.SetExpressionError( 405 lldb::eExpressionInterrupted, 406 "expression interrupted by callback after complete"); 407 return lldb::eExpressionInterrupted; 408 } 409 410 if (result_valobj_sp.get() == nullptr) { 411 result_valobj_sp = ValueObjectConstResult::Create( 412 exe_ctx.GetBestExecutionContextScope(), error); 413 } 414 415 return execution_results; 416 } 417 418 lldb::ExpressionResults 419 UserExpression::Execute(DiagnosticManager &diagnostic_manager, 420 ExecutionContext &exe_ctx, 421 const EvaluateExpressionOptions &options, 422 lldb::UserExpressionSP &shared_ptr_to_me, 423 lldb::ExpressionVariableSP &result_var) { 424 lldb::ExpressionResults expr_result = DoExecute( 425 diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var); 426 Target *target = exe_ctx.GetTargetPtr(); 427 if (options.GetResultIsInternal() && result_var && target) { 428 if (auto *persistent_state = 429 target->GetPersistentExpressionStateForLanguage(m_language)) 430 persistent_state->RemovePersistentVariable(result_var); 431 } 432 return expr_result; 433 } 434