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::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp, 102 ConstString &object_name, 103 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 LLDB_INVALID_ADDRESS; 111 } 112 113 lldb::VariableSP var_sp; 114 lldb::ValueObjectSP valobj_sp; 115 116 valobj_sp = 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 if (!err.Success() || !valobj_sp.get()) 125 return LLDB_INVALID_ADDRESS; 126 127 lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS); 128 129 if (ret == LLDB_INVALID_ADDRESS) { 130 err.SetErrorStringWithFormat( 131 "Couldn't load '%s' because its value couldn't be evaluated", 132 object_name.AsCString()); 133 return LLDB_INVALID_ADDRESS; 134 } 135 136 return ret; 137 } 138 139 lldb::ExpressionResults 140 UserExpression::Evaluate(ExecutionContext &exe_ctx, 141 const EvaluateExpressionOptions &options, 142 llvm::StringRef expr, llvm::StringRef prefix, 143 lldb::ValueObjectSP &result_valobj_sp, Status &error, 144 std::string *fixed_expression, ValueObject *ctx_obj) { 145 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step)); 146 147 if (ctx_obj) { 148 static unsigned const ctx_type_mask = lldb::TypeFlags::eTypeIsClass | 149 lldb::TypeFlags::eTypeIsStructUnion | 150 lldb::TypeFlags::eTypeIsReference; 151 if (!(ctx_obj->GetTypeInfo() & ctx_type_mask)) { 152 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 153 "an invalid type, can't run expressions."); 154 error.SetErrorString("a context object of an invalid type passed"); 155 return lldb::eExpressionSetupError; 156 } 157 } 158 159 if (ctx_obj && ctx_obj->GetTypeInfo() & lldb::TypeFlags::eTypeIsReference) { 160 Status error; 161 lldb::ValueObjectSP deref_ctx_sp = ctx_obj->Dereference(error); 162 if (!error.Success()) { 163 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 164 "a reference type that can't be dereferenced, can't run " 165 "expressions."); 166 error.SetErrorString( 167 "passed context object of an reference type cannot be deferenced"); 168 return lldb::eExpressionSetupError; 169 } 170 171 ctx_obj = deref_ctx_sp.get(); 172 } 173 174 lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy(); 175 lldb::LanguageType language = options.GetLanguage(); 176 const ResultType desired_type = options.DoesCoerceToId() 177 ? UserExpression::eResultTypeId 178 : UserExpression::eResultTypeAny; 179 lldb::ExpressionResults execution_results = lldb::eExpressionSetupError; 180 181 Target *target = exe_ctx.GetTargetPtr(); 182 if (!target) { 183 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a NULL target, can't " 184 "run expressions."); 185 error.SetErrorString("expression passed a null target"); 186 return lldb::eExpressionSetupError; 187 } 188 189 Process *process = exe_ctx.GetProcessPtr(); 190 191 if (process == nullptr || process->GetState() != lldb::eStateStopped) { 192 if (execution_policy == eExecutionPolicyAlways) { 193 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 194 "is not constant =="); 195 196 error.SetErrorString("expression needed to run but couldn't"); 197 198 return execution_results; 199 } 200 } 201 202 // Explicitly force the IR interpreter to evaluate the expression when the 203 // there is no process that supports running the expression for us. Don't 204 // change the execution policy if we have the special top-level policy that 205 // doesn't contain any expression and there is nothing to interpret. 206 if (execution_policy != eExecutionPolicyTopLevel && 207 (process == nullptr || !process->CanJIT())) 208 execution_policy = eExecutionPolicyNever; 209 210 // We need to set the expression execution thread here, turns out parse can 211 // call functions in the process of looking up symbols, which will escape the 212 // context set by exe_ctx passed to Execute. 213 lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP(); 214 ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher( 215 thread_sp); 216 217 llvm::StringRef full_prefix; 218 llvm::StringRef option_prefix(options.GetPrefix()); 219 std::string full_prefix_storage; 220 if (!prefix.empty() && !option_prefix.empty()) { 221 full_prefix_storage = std::string(prefix); 222 full_prefix_storage.append(std::string(option_prefix)); 223 full_prefix = full_prefix_storage; 224 } else if (!prefix.empty()) 225 full_prefix = prefix; 226 else 227 full_prefix = option_prefix; 228 229 // If the language was not specified in the expression command, set it to the 230 // language in the target's properties if specified, else default to the 231 // langage for the frame. 232 if (language == lldb::eLanguageTypeUnknown) { 233 if (target->GetLanguage() != lldb::eLanguageTypeUnknown) 234 language = target->GetLanguage(); 235 else if (StackFrame *frame = exe_ctx.GetFramePtr()) 236 language = frame->GetLanguage(); 237 } 238 239 lldb::UserExpressionSP user_expression_sp( 240 target->GetUserExpressionForLanguage(expr, full_prefix, language, 241 desired_type, options, ctx_obj, 242 error)); 243 if (error.Fail()) { 244 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==", 245 error.AsCString()); 246 return lldb::eExpressionSetupError; 247 } 248 249 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==", 250 expr.str()); 251 252 const bool keep_expression_in_memory = true; 253 const bool generate_debug_info = options.GetGenerateDebugInfo(); 254 255 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) { 256 error.SetErrorString("expression interrupted by callback before parse"); 257 result_valobj_sp = ValueObjectConstResult::Create( 258 exe_ctx.GetBestExecutionContextScope(), error); 259 return lldb::eExpressionInterrupted; 260 } 261 262 DiagnosticManager diagnostic_manager; 263 264 bool parse_success = 265 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy, 266 keep_expression_in_memory, generate_debug_info); 267 268 // Calculate the fixed expression always, since we need it for errors. 269 std::string tmp_fixed_expression; 270 if (fixed_expression == nullptr) 271 fixed_expression = &tmp_fixed_expression; 272 273 *fixed_expression = user_expression_sp->GetFixedText().str(); 274 275 // If there is a fixed expression, try to parse it: 276 if (!parse_success) { 277 // Delete the expression that failed to parse before attempting to parse 278 // the next expression. 279 user_expression_sp.reset(); 280 281 execution_results = lldb::eExpressionParseError; 282 if (!fixed_expression->empty() && options.GetAutoApplyFixIts()) { 283 const uint64_t max_fix_retries = options.GetRetriesWithFixIts(); 284 for (uint64_t i = 0; i < max_fix_retries; ++i) { 285 // Try parsing the fixed expression. 286 lldb::UserExpressionSP fixed_expression_sp( 287 target->GetUserExpressionForLanguage( 288 fixed_expression->c_str(), full_prefix, language, desired_type, 289 options, ctx_obj, error)); 290 DiagnosticManager fixed_diagnostic_manager; 291 parse_success = fixed_expression_sp->Parse( 292 fixed_diagnostic_manager, exe_ctx, execution_policy, 293 keep_expression_in_memory, generate_debug_info); 294 if (parse_success) { 295 diagnostic_manager.Clear(); 296 user_expression_sp = fixed_expression_sp; 297 break; 298 } else { 299 // The fixed expression also didn't parse. Let's check for any new 300 // Fix-Its we could try. 301 if (!fixed_expression_sp->GetFixedText().empty()) { 302 *fixed_expression = fixed_expression_sp->GetFixedText().str(); 303 } else { 304 // Fixed expression didn't compile without a fixit, don't retry and 305 // don't tell the user about it. 306 fixed_expression->clear(); 307 break; 308 } 309 } 310 } 311 } 312 313 if (!parse_success) { 314 std::string msg; 315 { 316 llvm::raw_string_ostream os(msg); 317 os << "expression failed to parse:\n"; 318 if (!diagnostic_manager.Diagnostics().empty()) 319 os << diagnostic_manager.GetString(); 320 else 321 os << "unknown error"; 322 if (target->GetEnableNotifyAboutFixIts() && fixed_expression && 323 !fixed_expression->empty()) 324 os << "\nfixed expression suggested:\n " << *fixed_expression; 325 } 326 error.SetExpressionError(execution_results, msg.c_str()); 327 } 328 } 329 330 if (parse_success) { 331 lldb::ExpressionVariableSP expr_result; 332 333 if (execution_policy == eExecutionPolicyNever && 334 !user_expression_sp->CanInterpret()) { 335 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 336 "is not constant =="); 337 338 if (!diagnostic_manager.Diagnostics().size()) 339 error.SetExpressionError(lldb::eExpressionSetupError, 340 "expression needed to run but couldn't"); 341 } else if (execution_policy == eExecutionPolicyTopLevel) { 342 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 343 return lldb::eExpressionCompleted; 344 } else { 345 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) { 346 error.SetExpressionError( 347 lldb::eExpressionInterrupted, 348 "expression interrupted by callback before execution"); 349 result_valobj_sp = ValueObjectConstResult::Create( 350 exe_ctx.GetBestExecutionContextScope(), error); 351 return lldb::eExpressionInterrupted; 352 } 353 354 diagnostic_manager.Clear(); 355 356 LLDB_LOG(log, "== [UserExpression::Evaluate] Executing expression =="); 357 358 execution_results = 359 user_expression_sp->Execute(diagnostic_manager, exe_ctx, options, 360 user_expression_sp, expr_result); 361 362 if (execution_results != lldb::eExpressionCompleted) { 363 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 364 "abnormally =="); 365 366 if (!diagnostic_manager.Diagnostics().size()) 367 error.SetExpressionError( 368 execution_results, "expression failed to execute, unknown error"); 369 else 370 error.SetExpressionError(execution_results, 371 diagnostic_manager.GetString().c_str()); 372 } else { 373 if (expr_result) { 374 result_valobj_sp = expr_result->GetValueObject(); 375 result_valobj_sp->SetPreferredDisplayLanguage(language); 376 377 LLDB_LOG(log, 378 "== [UserExpression::Evaluate] Execution completed " 379 "normally with result {0} ==", 380 result_valobj_sp->GetValueAsCString()); 381 } else { 382 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 383 "normally with no result =="); 384 385 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 386 } 387 } 388 } 389 } 390 391 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) { 392 error.SetExpressionError( 393 lldb::eExpressionInterrupted, 394 "expression interrupted by callback after complete"); 395 return lldb::eExpressionInterrupted; 396 } 397 398 if (result_valobj_sp.get() == nullptr) { 399 result_valobj_sp = ValueObjectConstResult::Create( 400 exe_ctx.GetBestExecutionContextScope(), error); 401 } 402 403 return execution_results; 404 } 405 406 lldb::ExpressionResults 407 UserExpression::Execute(DiagnosticManager &diagnostic_manager, 408 ExecutionContext &exe_ctx, 409 const EvaluateExpressionOptions &options, 410 lldb::UserExpressionSP &shared_ptr_to_me, 411 lldb::ExpressionVariableSP &result_var) { 412 lldb::ExpressionResults expr_result = DoExecute( 413 diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var); 414 Target *target = exe_ctx.GetTargetPtr(); 415 if (options.GetResultIsInternal() && result_var && target) { 416 if (auto *persistent_state = 417 target->GetPersistentExpressionStateForLanguage(m_language)) 418 persistent_state->RemovePersistentVariable(result_var); 419 } 420 return expr_result; 421 } 422