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/Log.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::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp, 101 ConstString &object_name, 102 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 LLDB_INVALID_ADDRESS; 110 } 111 112 lldb::VariableSP var_sp; 113 lldb::ValueObjectSP valobj_sp; 114 115 valobj_sp = 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 if (!err.Success() || !valobj_sp.get()) 124 return LLDB_INVALID_ADDRESS; 125 126 lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS); 127 128 if (ret == LLDB_INVALID_ADDRESS) { 129 err.SetErrorStringWithFormat( 130 "Couldn't load '%s' because its value couldn't be evaluated", 131 object_name.AsCString()); 132 return LLDB_INVALID_ADDRESS; 133 } 134 135 return ret; 136 } 137 138 lldb::ExpressionResults 139 UserExpression::Evaluate(ExecutionContext &exe_ctx, 140 const EvaluateExpressionOptions &options, 141 llvm::StringRef expr, llvm::StringRef prefix, 142 lldb::ValueObjectSP &result_valobj_sp, Status &error, 143 std::string *fixed_expression, ValueObject *ctx_obj) { 144 Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS | 145 LIBLLDB_LOG_STEP)); 146 147 if (ctx_obj) { 148 static unsigned const ctx_type_mask = 149 lldb::TypeFlags::eTypeIsClass | lldb::TypeFlags::eTypeIsStructUnion; 150 if (!(ctx_obj->GetTypeInfo() & ctx_type_mask)) { 151 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of " 152 "an invalid type, can't run expressions."); 153 error.SetErrorString("a context object of an invalid type passed"); 154 return lldb::eExpressionSetupError; 155 } 156 } 157 158 lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy(); 159 lldb::LanguageType language = options.GetLanguage(); 160 const ResultType desired_type = options.DoesCoerceToId() 161 ? UserExpression::eResultTypeId 162 : UserExpression::eResultTypeAny; 163 lldb::ExpressionResults execution_results = lldb::eExpressionSetupError; 164 165 Target *target = exe_ctx.GetTargetPtr(); 166 if (!target) { 167 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a NULL target, can't " 168 "run expressions."); 169 error.SetErrorString("expression passed a null target"); 170 return lldb::eExpressionSetupError; 171 } 172 173 Process *process = exe_ctx.GetProcessPtr(); 174 175 if (process == nullptr || process->GetState() != lldb::eStateStopped) { 176 if (execution_policy == eExecutionPolicyAlways) { 177 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 178 "is not constant =="); 179 180 error.SetErrorString("expression needed to run but couldn't"); 181 182 return execution_results; 183 } 184 } 185 186 // Explicitly force the IR interpreter to evaluate the expression when the 187 // there is no process that supports running the expression for us. Don't 188 // change the execution policy if we have the special top-level policy that 189 // doesn't contain any expression and there is nothing to interpret. 190 if (execution_policy != eExecutionPolicyTopLevel && 191 (process == nullptr || !process->CanJIT())) 192 execution_policy = eExecutionPolicyNever; 193 194 // We need to set the expression execution thread here, turns out parse can 195 // call functions in the process of looking up symbols, which will escape the 196 // context set by exe_ctx passed to Execute. 197 lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP(); 198 ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher( 199 thread_sp); 200 201 llvm::StringRef full_prefix; 202 llvm::StringRef option_prefix(options.GetPrefix()); 203 std::string full_prefix_storage; 204 if (!prefix.empty() && !option_prefix.empty()) { 205 full_prefix_storage = std::string(prefix); 206 full_prefix_storage.append(std::string(option_prefix)); 207 full_prefix = full_prefix_storage; 208 } else if (!prefix.empty()) 209 full_prefix = prefix; 210 else 211 full_prefix = option_prefix; 212 213 // If the language was not specified in the expression command, set it to the 214 // language in the target's properties if specified, else default to the 215 // langage for the frame. 216 if (language == lldb::eLanguageTypeUnknown) { 217 if (target->GetLanguage() != lldb::eLanguageTypeUnknown) 218 language = target->GetLanguage(); 219 else if (StackFrame *frame = exe_ctx.GetFramePtr()) 220 language = frame->GetLanguage(); 221 } 222 223 lldb::UserExpressionSP user_expression_sp( 224 target->GetUserExpressionForLanguage(expr, full_prefix, language, 225 desired_type, options, ctx_obj, 226 error)); 227 if (error.Fail()) { 228 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==", 229 error.AsCString()); 230 return lldb::eExpressionSetupError; 231 } 232 233 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==", 234 expr.str()); 235 236 const bool keep_expression_in_memory = true; 237 const bool generate_debug_info = options.GetGenerateDebugInfo(); 238 239 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) { 240 error.SetErrorString("expression interrupted by callback before parse"); 241 result_valobj_sp = ValueObjectConstResult::Create( 242 exe_ctx.GetBestExecutionContextScope(), error); 243 return lldb::eExpressionInterrupted; 244 } 245 246 DiagnosticManager diagnostic_manager; 247 248 bool parse_success = 249 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy, 250 keep_expression_in_memory, generate_debug_info); 251 252 // Calculate the fixed expression always, since we need it for errors. 253 std::string tmp_fixed_expression; 254 if (fixed_expression == nullptr) 255 fixed_expression = &tmp_fixed_expression; 256 257 *fixed_expression = user_expression_sp->GetFixedText().str(); 258 259 // If there is a fixed expression, try to parse it: 260 if (!parse_success) { 261 // Delete the expression that failed to parse before attempting to parse 262 // the next expression. 263 user_expression_sp.reset(); 264 265 execution_results = lldb::eExpressionParseError; 266 if (!fixed_expression->empty() && options.GetAutoApplyFixIts()) { 267 const uint64_t max_fix_retries = options.GetRetriesWithFixIts(); 268 for (uint64_t i = 0; i < max_fix_retries; ++i) { 269 // Try parsing the fixed expression. 270 lldb::UserExpressionSP fixed_expression_sp( 271 target->GetUserExpressionForLanguage( 272 fixed_expression->c_str(), full_prefix, language, desired_type, 273 options, ctx_obj, error)); 274 DiagnosticManager fixed_diagnostic_manager; 275 parse_success = fixed_expression_sp->Parse( 276 fixed_diagnostic_manager, exe_ctx, execution_policy, 277 keep_expression_in_memory, generate_debug_info); 278 if (parse_success) { 279 diagnostic_manager.Clear(); 280 user_expression_sp = fixed_expression_sp; 281 break; 282 } else { 283 // The fixed expression also didn't parse. Let's check for any new 284 // Fix-Its we could try. 285 if (!fixed_expression_sp->GetFixedText().empty()) { 286 *fixed_expression = fixed_expression_sp->GetFixedText().str(); 287 } else { 288 // Fixed expression didn't compile without a fixit, don't retry and 289 // don't tell the user about it. 290 fixed_expression->clear(); 291 break; 292 } 293 } 294 } 295 } 296 297 if (!parse_success) { 298 std::string msg; 299 { 300 llvm::raw_string_ostream os(msg); 301 os << "expression failed to parse:\n"; 302 if (!diagnostic_manager.Diagnostics().empty()) 303 os << diagnostic_manager.GetString(); 304 else 305 os << "unknown error"; 306 if (target->GetEnableNotifyAboutFixIts() && fixed_expression && 307 !fixed_expression->empty()) 308 os << "\nfixed expression suggested:\n " << *fixed_expression; 309 } 310 error.SetExpressionError(execution_results, msg.c_str()); 311 } 312 } 313 314 if (parse_success) { 315 lldb::ExpressionVariableSP expr_result; 316 317 if (execution_policy == eExecutionPolicyNever && 318 !user_expression_sp->CanInterpret()) { 319 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but " 320 "is not constant =="); 321 322 if (!diagnostic_manager.Diagnostics().size()) 323 error.SetExpressionError(lldb::eExpressionSetupError, 324 "expression needed to run but couldn't"); 325 } else if (execution_policy == eExecutionPolicyTopLevel) { 326 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 327 return lldb::eExpressionCompleted; 328 } else { 329 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) { 330 error.SetExpressionError( 331 lldb::eExpressionInterrupted, 332 "expression interrupted by callback before execution"); 333 result_valobj_sp = ValueObjectConstResult::Create( 334 exe_ctx.GetBestExecutionContextScope(), error); 335 return lldb::eExpressionInterrupted; 336 } 337 338 diagnostic_manager.Clear(); 339 340 LLDB_LOG(log, "== [UserExpression::Evaluate] Executing expression =="); 341 342 execution_results = 343 user_expression_sp->Execute(diagnostic_manager, exe_ctx, options, 344 user_expression_sp, expr_result); 345 346 if (execution_results != lldb::eExpressionCompleted) { 347 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 348 "abnormally =="); 349 350 if (!diagnostic_manager.Diagnostics().size()) 351 error.SetExpressionError( 352 execution_results, "expression failed to execute, unknown error"); 353 else 354 error.SetExpressionError(execution_results, 355 diagnostic_manager.GetString().c_str()); 356 } else { 357 if (expr_result) { 358 result_valobj_sp = expr_result->GetValueObject(); 359 result_valobj_sp->SetPreferredDisplayLanguage(language); 360 361 LLDB_LOG(log, 362 "== [UserExpression::Evaluate] Execution completed " 363 "normally with result {0} ==", 364 result_valobj_sp->GetValueAsCString()); 365 } else { 366 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed " 367 "normally with no result =="); 368 369 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric); 370 } 371 } 372 } 373 } 374 375 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) { 376 error.SetExpressionError( 377 lldb::eExpressionInterrupted, 378 "expression interrupted by callback after complete"); 379 return lldb::eExpressionInterrupted; 380 } 381 382 if (result_valobj_sp.get() == nullptr) { 383 result_valobj_sp = ValueObjectConstResult::Create( 384 exe_ctx.GetBestExecutionContextScope(), error); 385 } 386 387 return execution_results; 388 } 389 390 lldb::ExpressionResults 391 UserExpression::Execute(DiagnosticManager &diagnostic_manager, 392 ExecutionContext &exe_ctx, 393 const EvaluateExpressionOptions &options, 394 lldb::UserExpressionSP &shared_ptr_to_me, 395 lldb::ExpressionVariableSP &result_var) { 396 lldb::ExpressionResults expr_result = DoExecute( 397 diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var); 398 Target *target = exe_ctx.GetTargetPtr(); 399 if (options.GetResultIsInternal() && result_var && target) { 400 if (auto *persistent_state = 401 target->GetPersistentExpressionStateForLanguage(m_language)) 402 persistent_state->RemovePersistentVariable(result_var); 403 } 404 return expr_result; 405 } 406