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 || process->GetState() != lldb::eStateStopped) { 198 if (execution_policy == eExecutionPolicyAlways) { 199 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 200 "is not constant =="); 201 202 error.SetErrorString("expression needed to run but couldn't"); 203 204 return execution_results; 205 } 206 } 207 208 // Explicitly force the IR interpreter to evaluate the expression when the 209 // there is no process that supports running the expression for us. Don't 210 // change the execution policy if we have the special top-level policy that 211 // doesn't contain any expression and there is nothing to interpret. 212 if (execution_policy != eExecutionPolicyTopLevel && 213 (process == nullptr || !process->CanJIT())) 214 execution_policy = eExecutionPolicyNever; 215 216 // We need to set the expression execution thread here, turns out parse can 217 // call functions in the process of looking up symbols, which will escape the 218 // context set by exe_ctx passed to Execute. 219 lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP(); 220 ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher( 221 thread_sp); 222 223 llvm::StringRef full_prefix; 224 llvm::StringRef option_prefix(options.GetPrefix()); 225 std::string full_prefix_storage; 226 if (!prefix.empty() && !option_prefix.empty()) { 227 full_prefix_storage = std::string(prefix); 228 full_prefix_storage.append(std::string(option_prefix)); 229 full_prefix = full_prefix_storage; 230 } else if (!prefix.empty()) 231 full_prefix = prefix; 232 else 233 full_prefix = option_prefix; 234 235 // If the language was not specified in the expression command, set it to the 236 // language in the target's properties if specified, else default to the 237 // langage for the frame. 238 if (language == lldb::eLanguageTypeUnknown) { 239 if (target->GetLanguage() != lldb::eLanguageTypeUnknown) 240 language = target->GetLanguage(); 241 else if (StackFrame *frame = exe_ctx.GetFramePtr()) 242 language = frame->GetLanguage(); 243 } 244 245 lldb::UserExpressionSP user_expression_sp( 246 target->GetUserExpressionForLanguage(expr, full_prefix, language, 247 desired_type, options, ctx_obj, 248 error)); 249 if (error.Fail()) { 250 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==", 251 error.AsCString()); 252 return lldb::eExpressionSetupError; 253 } 254 255 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==", 256 expr.str()); 257 258 const bool keep_expression_in_memory = true; 259 const bool generate_debug_info = options.GetGenerateDebugInfo(); 260 261 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) { 262 error.SetErrorString("expression interrupted by callback before parse"); 263 result_valobj_sp = ValueObjectConstResult::Create( 264 exe_ctx.GetBestExecutionContextScope(), error); 265 return lldb::eExpressionInterrupted; 266 } 267 268 DiagnosticManager diagnostic_manager; 269 270 bool parse_success = 271 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy, 272 keep_expression_in_memory, generate_debug_info); 273 274 // Calculate the fixed expression always, since we need it for errors. 275 std::string tmp_fixed_expression; 276 if (fixed_expression == nullptr) 277 fixed_expression = &tmp_fixed_expression; 278 279 *fixed_expression = user_expression_sp->GetFixedText().str(); 280 281 // If there is a fixed expression, try to parse it: 282 if (!parse_success) { 283 // Delete the expression that failed to parse before attempting to parse 284 // the next expression. 285 user_expression_sp.reset(); 286 287 execution_results = lldb::eExpressionParseError; 288 if (!fixed_expression->empty() && options.GetAutoApplyFixIts()) { 289 const uint64_t max_fix_retries = options.GetRetriesWithFixIts(); 290 for (uint64_t i = 0; i < max_fix_retries; ++i) { 291 // Try parsing the fixed expression. 292 lldb::UserExpressionSP fixed_expression_sp( 293 target->GetUserExpressionForLanguage( 294 fixed_expression->c_str(), full_prefix, language, desired_type, 295 options, ctx_obj, error)); 296 DiagnosticManager fixed_diagnostic_manager; 297 parse_success = fixed_expression_sp->Parse( 298 fixed_diagnostic_manager, exe_ctx, execution_policy, 299 keep_expression_in_memory, generate_debug_info); 300 if (parse_success) { 301 diagnostic_manager.Clear(); 302 user_expression_sp = fixed_expression_sp; 303 break; 304 } else { 305 // The fixed expression also didn't parse. Let's check for any new 306 // Fix-Its we could try. 307 if (!fixed_expression_sp->GetFixedText().empty()) { 308 *fixed_expression = fixed_expression_sp->GetFixedText().str(); 309 } else { 310 // Fixed expression didn't compile without a fixit, don't retry and 311 // don't tell the user about it. 312 fixed_expression->clear(); 313 break; 314 } 315 } 316 } 317 } 318 319 if (!parse_success) { 320 std::string msg; 321 { 322 llvm::raw_string_ostream os(msg); 323 os << "expression failed to parse:\n"; 324 if (!diagnostic_manager.Diagnostics().empty()) 325 os << diagnostic_manager.GetString(); 326 else 327 os << "unknown error"; 328 if (target->GetEnableNotifyAboutFixIts() && fixed_expression && 329 !fixed_expression->empty()) 330 os << "\nfixed expression suggested:\n " << *fixed_expression; 331 } 332 error.SetExpressionError(execution_results, msg.c_str()); 333 } 334 } 335 336 if (parse_success) { 337 lldb::ExpressionVariableSP expr_result; 338 339 if (execution_policy == eExecutionPolicyNever && 340 !user_expression_sp->CanInterpret()) { 341 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 342 "is not constant =="); 343 344 if (!diagnostic_manager.Diagnostics().size()) 345 error.SetExpressionError(lldb::eExpressionSetupError, 346 "expression needed to run but couldn't"); 347 } else if (execution_policy == eExecutionPolicyTopLevel) { 348 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 349 return lldb::eExpressionCompleted; 350 } else { 351 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) { 352 error.SetExpressionError( 353 lldb::eExpressionInterrupted, 354 "expression interrupted by callback before execution"); 355 result_valobj_sp = ValueObjectConstResult::Create( 356 exe_ctx.GetBestExecutionContextScope(), error); 357 return lldb::eExpressionInterrupted; 358 } 359 360 diagnostic_manager.Clear(); 361 362 LLDB_LOG(log, "== [UserExpression::Evaluate] Executing expression =="); 363 364 execution_results = 365 user_expression_sp->Execute(diagnostic_manager, exe_ctx, options, 366 user_expression_sp, expr_result); 367 368 if (execution_results != lldb::eExpressionCompleted) { 369 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 370 "abnormally =="); 371 372 if (!diagnostic_manager.Diagnostics().size()) 373 error.SetExpressionError( 374 execution_results, "expression failed to execute, unknown error"); 375 else 376 error.SetExpressionError(execution_results, 377 diagnostic_manager.GetString().c_str()); 378 } else { 379 if (expr_result) { 380 result_valobj_sp = expr_result->GetValueObject(); 381 result_valobj_sp->SetPreferredDisplayLanguage(language); 382 383 LLDB_LOG(log, 384 "== [UserExpression::Evaluate] Execution completed " 385 "normally with result {0} ==", 386 result_valobj_sp->GetValueAsCString()); 387 } else { 388 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 389 "normally with no result =="); 390 391 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 392 } 393 } 394 } 395 } 396 397 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) { 398 error.SetExpressionError( 399 lldb::eExpressionInterrupted, 400 "expression interrupted by callback after complete"); 401 return lldb::eExpressionInterrupted; 402 } 403 404 if (result_valobj_sp.get() == nullptr) { 405 result_valobj_sp = ValueObjectConstResult::Create( 406 exe_ctx.GetBestExecutionContextScope(), error); 407 } 408 409 return execution_results; 410 } 411 412 lldb::ExpressionResults 413 UserExpression::Execute(DiagnosticManager &diagnostic_manager, 414 ExecutionContext &exe_ctx, 415 const EvaluateExpressionOptions &options, 416 lldb::UserExpressionSP &shared_ptr_to_me, 417 lldb::ExpressionVariableSP &result_var) { 418 lldb::ExpressionResults expr_result = DoExecute( 419 diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var); 420 Target *target = exe_ctx.GetTargetPtr(); 421 if (options.GetResultIsInternal() && result_var && target) { 422 if (auto *persistent_state = 423 target->GetPersistentExpressionStateForLanguage(m_language)) 424 persistent_state->RemovePersistentVariable(result_var); 425 } 426 return expr_result; 427 } 428