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/ValueObjectConstResult.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 43 using namespace lldb_private; 44 45 char UserExpression::ID; 46 47 UserExpression::UserExpression(ExecutionContextScope &exe_scope, 48 llvm::StringRef expr, llvm::StringRef prefix, 49 lldb::LanguageType language, 50 ResultType desired_type, 51 const EvaluateExpressionOptions &options) 52 : Expression(exe_scope), m_expr_text(std::string(expr)), 53 m_expr_prefix(std::string(prefix)), m_language(language), 54 m_desired_type(desired_type), m_options(options) {} 55 56 UserExpression::~UserExpression() = default; 57 58 void UserExpression::InstallContext(ExecutionContext &exe_ctx) { 59 m_jit_process_wp = exe_ctx.GetProcessSP(); 60 61 lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP(); 62 63 if (frame_sp) 64 m_address = frame_sp->GetFrameCodeAddress(); 65 } 66 67 bool UserExpression::LockAndCheckContext(ExecutionContext &exe_ctx, 68 lldb::TargetSP &target_sp, 69 lldb::ProcessSP &process_sp, 70 lldb::StackFrameSP &frame_sp) { 71 lldb::ProcessSP expected_process_sp = m_jit_process_wp.lock(); 72 process_sp = exe_ctx.GetProcessSP(); 73 74 if (process_sp != expected_process_sp) 75 return false; 76 77 process_sp = exe_ctx.GetProcessSP(); 78 target_sp = exe_ctx.GetTargetSP(); 79 frame_sp = exe_ctx.GetFrameSP(); 80 81 if (m_address.IsValid()) { 82 if (!frame_sp) 83 return false; 84 return (Address::CompareLoadAddress(m_address, 85 frame_sp->GetFrameCodeAddress(), 86 target_sp.get()) == 0); 87 } 88 89 return true; 90 } 91 92 bool UserExpression::MatchesContext(ExecutionContext &exe_ctx) { 93 lldb::TargetSP target_sp; 94 lldb::ProcessSP process_sp; 95 lldb::StackFrameSP frame_sp; 96 97 return LockAndCheckContext(exe_ctx, target_sp, process_sp, frame_sp); 98 } 99 100 lldb::ValueObjectSP UserExpression::GetObjectPointerValueObject( 101 lldb::StackFrameSP frame_sp, llvm::StringRef object_name, Status &err) { 102 err.Clear(); 103 104 if (!frame_sp) { 105 err.SetErrorStringWithFormatv( 106 "Couldn't load '{0}' because the context is incomplete", object_name); 107 return {}; 108 } 109 110 lldb::VariableSP var_sp; 111 lldb::ValueObjectSP valobj_sp; 112 113 return frame_sp->GetValueForVariableExpressionPath( 114 object_name, lldb::eNoDynamicValues, 115 StackFrame::eExpressionPathOptionCheckPtrVsMember | 116 StackFrame::eExpressionPathOptionsNoFragileObjcIvar | 117 StackFrame::eExpressionPathOptionsNoSyntheticChildren | 118 StackFrame::eExpressionPathOptionsNoSyntheticArrayRange, 119 var_sp, err); 120 } 121 122 lldb::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp, 123 llvm::StringRef object_name, 124 Status &err) { 125 auto valobj_sp = 126 GetObjectPointerValueObject(std::move(frame_sp), object_name, err); 127 128 if (!err.Success() || !valobj_sp.get()) 129 return LLDB_INVALID_ADDRESS; 130 131 lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS); 132 133 if (ret == LLDB_INVALID_ADDRESS) { 134 err.SetErrorStringWithFormatv( 135 "Couldn't load '{0}' because its value couldn't be evaluated", 136 object_name); 137 return LLDB_INVALID_ADDRESS; 138 } 139 140 return ret; 141 } 142 143 lldb::ExpressionResults 144 UserExpression::Evaluate(ExecutionContext &exe_ctx, 145 const EvaluateExpressionOptions &options, 146 llvm::StringRef expr, llvm::StringRef prefix, 147 lldb::ValueObjectSP &result_valobj_sp, Status &error, 148 std::string *fixed_expression, ValueObject *ctx_obj) { 149 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step)); 150 151 if (ctx_obj) { 152 static unsigned const ctx_type_mask = lldb::TypeFlags::eTypeIsClass | 153 lldb::TypeFlags::eTypeIsStructUnion | 154 lldb::TypeFlags::eTypeIsReference; 155 if (!(ctx_obj->GetTypeInfo() & ctx_type_mask)) { 156 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 157 "an invalid type, can't run expressions."); 158 error.SetErrorString("a context object of an invalid type passed"); 159 return lldb::eExpressionSetupError; 160 } 161 } 162 163 if (ctx_obj && ctx_obj->GetTypeInfo() & lldb::TypeFlags::eTypeIsReference) { 164 Status error; 165 lldb::ValueObjectSP deref_ctx_sp = ctx_obj->Dereference(error); 166 if (!error.Success()) { 167 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 168 "a reference type that can't be dereferenced, can't run " 169 "expressions."); 170 error.SetErrorString( 171 "passed context object of an reference type cannot be deferenced"); 172 return lldb::eExpressionSetupError; 173 } 174 175 ctx_obj = deref_ctx_sp.get(); 176 } 177 178 lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy(); 179 lldb::LanguageType language = options.GetLanguage(); 180 const ResultType desired_type = options.DoesCoerceToId() 181 ? UserExpression::eResultTypeId 182 : UserExpression::eResultTypeAny; 183 lldb::ExpressionResults execution_results = lldb::eExpressionSetupError; 184 185 Target *target = exe_ctx.GetTargetPtr(); 186 if (!target) { 187 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a NULL target, can't " 188 "run expressions."); 189 error.SetErrorString("expression passed a null target"); 190 return lldb::eExpressionSetupError; 191 } 192 193 Process *process = exe_ctx.GetProcessPtr(); 194 195 if (process == nullptr && execution_policy == eExecutionPolicyAlways) { 196 LLDB_LOG(log, "== [UserExpression::Evaluate] No process, but the policy is " 197 "eExecutionPolicyAlways"); 198 199 error.SetErrorString("expression needed to run but couldn't: no process"); 200 201 return execution_results; 202 } 203 204 // Since we might need to allocate memory, we need to be stopped to run 205 // an expression. 206 if (process != nullptr && process->GetState() != lldb::eStateStopped) { 207 error.SetErrorStringWithFormatv( 208 "unable to evaluate expression while the process is {0}: the process " 209 "must be stopped because the expression might require allocating " 210 "memory.", 211 StateAsCString(process->GetState())); 212 return execution_results; 213 } 214 215 // Explicitly force the IR interpreter to evaluate the expression when the 216 // there is no process that supports running the expression for us. Don't 217 // change the execution policy if we have the special top-level policy that 218 // doesn't contain any expression and there is nothing to interpret. 219 if (execution_policy != eExecutionPolicyTopLevel && 220 (process == nullptr || !process->CanJIT())) 221 execution_policy = eExecutionPolicyNever; 222 223 // We need to set the expression execution thread here, turns out parse can 224 // call functions in the process of looking up symbols, which will escape the 225 // context set by exe_ctx passed to Execute. 226 lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP(); 227 ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher( 228 thread_sp); 229 230 llvm::StringRef full_prefix; 231 llvm::StringRef option_prefix(options.GetPrefix()); 232 std::string full_prefix_storage; 233 if (!prefix.empty() && !option_prefix.empty()) { 234 full_prefix_storage = std::string(prefix); 235 full_prefix_storage.append(std::string(option_prefix)); 236 full_prefix = full_prefix_storage; 237 } else if (!prefix.empty()) 238 full_prefix = prefix; 239 else 240 full_prefix = option_prefix; 241 242 // If the language was not specified in the expression command, set it to the 243 // language in the target's properties if specified, else default to the 244 // langage for the frame. 245 if (language == lldb::eLanguageTypeUnknown) { 246 if (target->GetLanguage() != lldb::eLanguageTypeUnknown) 247 language = target->GetLanguage(); 248 else if (StackFrame *frame = exe_ctx.GetFramePtr()) 249 language = frame->GetLanguage(); 250 } 251 252 lldb::UserExpressionSP user_expression_sp( 253 target->GetUserExpressionForLanguage(expr, full_prefix, language, 254 desired_type, options, ctx_obj, 255 error)); 256 if (error.Fail() || !user_expression_sp) { 257 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==", 258 error.AsCString()); 259 return lldb::eExpressionSetupError; 260 } 261 262 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==", 263 expr.str()); 264 265 const bool keep_expression_in_memory = true; 266 const bool generate_debug_info = options.GetGenerateDebugInfo(); 267 268 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) { 269 error.SetErrorString("expression interrupted by callback before parse"); 270 result_valobj_sp = ValueObjectConstResult::Create( 271 exe_ctx.GetBestExecutionContextScope(), error); 272 return lldb::eExpressionInterrupted; 273 } 274 275 DiagnosticManager diagnostic_manager; 276 277 bool parse_success = 278 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy, 279 keep_expression_in_memory, generate_debug_info); 280 281 // Calculate the fixed expression always, since we need it for errors. 282 std::string tmp_fixed_expression; 283 if (fixed_expression == nullptr) 284 fixed_expression = &tmp_fixed_expression; 285 286 *fixed_expression = user_expression_sp->GetFixedText().str(); 287 288 // If there is a fixed expression, try to parse it: 289 if (!parse_success) { 290 // Delete the expression that failed to parse before attempting to parse 291 // the next expression. 292 user_expression_sp.reset(); 293 294 execution_results = lldb::eExpressionParseError; 295 if (!fixed_expression->empty() && options.GetAutoApplyFixIts()) { 296 const uint64_t max_fix_retries = options.GetRetriesWithFixIts(); 297 for (uint64_t i = 0; i < max_fix_retries; ++i) { 298 // Try parsing the fixed expression. 299 lldb::UserExpressionSP fixed_expression_sp( 300 target->GetUserExpressionForLanguage( 301 fixed_expression->c_str(), full_prefix, language, desired_type, 302 options, ctx_obj, error)); 303 DiagnosticManager fixed_diagnostic_manager; 304 parse_success = fixed_expression_sp->Parse( 305 fixed_diagnostic_manager, exe_ctx, execution_policy, 306 keep_expression_in_memory, generate_debug_info); 307 if (parse_success) { 308 diagnostic_manager.Clear(); 309 user_expression_sp = fixed_expression_sp; 310 break; 311 } else { 312 // The fixed expression also didn't parse. Let's check for any new 313 // Fix-Its we could try. 314 if (!fixed_expression_sp->GetFixedText().empty()) { 315 *fixed_expression = fixed_expression_sp->GetFixedText().str(); 316 } else { 317 // Fixed expression didn't compile without a fixit, don't retry and 318 // don't tell the user about it. 319 fixed_expression->clear(); 320 break; 321 } 322 } 323 } 324 } 325 326 if (!parse_success) { 327 std::string msg; 328 { 329 llvm::raw_string_ostream os(msg); 330 if (!diagnostic_manager.Diagnostics().empty()) 331 os << diagnostic_manager.GetString(); 332 else 333 os << "expression failed to parse (no further compiler diagnostics)"; 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.GetSuppressPersistentResult() && 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