1 //===-- ClangUserExpression.h -----------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef liblldb_ClangUserExpression_h_ 11 #define liblldb_ClangUserExpression_h_ 12 13 // C Includes 14 // C++ Includes 15 #include <string> 16 #include <map> 17 #include <vector> 18 19 // Other libraries and framework includes 20 // Project includes 21 22 #include "lldb/lldb-forward.h" 23 #include "lldb/lldb-private.h" 24 #include "lldb/Core/Address.h" 25 #include "lldb/Core/ClangForward.h" 26 #include "lldb/Expression/ClangExpression.h" 27 #include "lldb/Expression/ClangExpressionVariable.h" 28 #include "lldb/Expression/IRForTarget.h" 29 #include "lldb/Expression/Materializer.h" 30 #include "lldb/Symbol/TaggedASTType.h" 31 #include "lldb/Target/ExecutionContext.h" 32 33 #include "llvm/ExecutionEngine/JITMemoryManager.h" 34 35 namespace lldb_private 36 { 37 38 //---------------------------------------------------------------------- 39 /// @class ClangUserExpression ClangUserExpression.h "lldb/Expression/ClangUserExpression.h" 40 /// @brief Encapsulates a single expression for use with Clang 41 /// 42 /// LLDB uses expressions for various purposes, notably to call functions 43 /// and as a backend for the expr command. ClangUserExpression encapsulates 44 /// the objects needed to parse and interpret or JIT an expression. It 45 /// uses the Clang parser to produce LLVM IR from the expression. 46 //---------------------------------------------------------------------- 47 class ClangUserExpression : public ClangExpression 48 { 49 public: 50 typedef std::shared_ptr<ClangUserExpression> ClangUserExpressionSP; 51 52 enum { kDefaultTimeout = 500000u }; 53 //------------------------------------------------------------------ 54 /// Constructor 55 /// 56 /// @param[in] expr 57 /// The expression to parse. 58 /// 59 /// @param[in] expr_prefix 60 /// If non-NULL, a C string containing translation-unit level 61 /// definitions to be included when the expression is parsed. 62 /// 63 /// @param[in] language 64 /// If not eLanguageTypeUnknown, a language to use when parsing 65 /// the expression. Currently restricted to those languages 66 /// supported by Clang. 67 /// 68 /// @param[in] desired_type 69 /// If not eResultTypeAny, the type to use for the expression 70 /// result. 71 //------------------------------------------------------------------ 72 ClangUserExpression (const char *expr, 73 const char *expr_prefix, 74 lldb::LanguageType language, 75 ResultType desired_type); 76 77 //------------------------------------------------------------------ 78 /// Destructor 79 //------------------------------------------------------------------ 80 virtual 81 ~ClangUserExpression (); 82 83 //------------------------------------------------------------------ 84 /// Parse the expression 85 /// 86 /// @param[in] error_stream 87 /// A stream to print parse errors and warnings to. 88 /// 89 /// @param[in] exe_ctx 90 /// The execution context to use when looking up entities that 91 /// are needed for parsing (locations of functions, types of 92 /// variables, persistent variables, etc.) 93 /// 94 /// @param[in] execution_policy 95 /// Determines whether interpretation is possible or mandatory. 96 /// 97 /// @param[in] keep_result_in_memory 98 /// True if the resulting persistent variable should reside in 99 /// target memory, if applicable. 100 /// 101 /// @return 102 /// True on success (no errors); false otherwise. 103 //------------------------------------------------------------------ 104 bool 105 Parse (Stream &error_stream, 106 ExecutionContext &exe_ctx, 107 lldb_private::ExecutionPolicy execution_policy, 108 bool keep_result_in_memory); 109 110 bool CanInterpret()111 CanInterpret () 112 { 113 return m_can_interpret; 114 } 115 116 bool 117 MatchesContext (ExecutionContext &exe_ctx); 118 119 //------------------------------------------------------------------ 120 /// Execute the parsed expression 121 /// 122 /// @param[in] error_stream 123 /// A stream to print errors to. 124 /// 125 /// @param[in] exe_ctx 126 /// The execution context to use when looking up entities that 127 /// are needed for parsing (locations of variables, etc.) 128 /// 129 /// @param[in] unwind_on_error 130 /// If true, and the execution stops before completion, we unwind the 131 /// function call, and return the program state to what it was before the 132 /// execution. If false, we leave the program in the stopped state. 133 /// 134 /// @param[in] ignore_breakpoints 135 /// If true, ignore breakpoints while executing the expression. 136 /// 137 /// @param[in] shared_ptr_to_me 138 /// This is a shared pointer to this ClangUserExpression. This is 139 /// needed because Execute can push a thread plan that will hold onto 140 /// the ClangUserExpression for an unbounded period of time. So you 141 /// need to give the thread plan a reference to this object that can 142 /// keep it alive. 143 /// 144 /// @param[in] result 145 /// A pointer to direct at the persistent variable in which the 146 /// expression's result is stored. 147 /// 148 /// @param[in] try_all_threads 149 /// If true, then we will try to run all threads if the function doesn't complete on 150 /// one thread. See timeout_usec for the interaction of this variable and 151 /// the timeout. 152 /// 153 /// @param[in] timeout_usec 154 /// Timeout value (0 for no timeout). If try_all_threads is true, then we 155 /// will try on one thread for the lesser of .25 sec and half the total timeout. 156 /// then switch to running all threads, otherwise this will be the total timeout. 157 /// 158 /// 159 /// @return 160 /// A Process::Execution results value. 161 //------------------------------------------------------------------ 162 ExecutionResults 163 Execute (Stream &error_stream, 164 ExecutionContext &exe_ctx, 165 bool unwind_on_error, 166 bool ignore_breakpoints, 167 ClangUserExpressionSP &shared_ptr_to_me, 168 lldb::ClangExpressionVariableSP &result, 169 bool try_all_threads, 170 uint32_t timeout_usec); 171 172 ThreadPlan * 173 GetThreadPlanToExecuteJITExpression (Stream &error_stream, 174 ExecutionContext &exe_ctx); 175 176 //------------------------------------------------------------------ 177 /// Apply the side effects of the function to program state. 178 /// 179 /// @param[in] error_stream 180 /// A stream to print errors to. 181 /// 182 /// @param[in] exe_ctx 183 /// The execution context to use when looking up entities that 184 /// are needed for parsing (locations of variables, etc.) 185 /// 186 /// @param[in] result 187 /// A pointer to direct at the persistent variable in which the 188 /// expression's result is stored. 189 /// 190 /// @param[in] function_stack_pointer 191 /// A pointer to the base of the function's stack frame. This 192 /// is used to determine whether the expession result resides in 193 /// memory that will still be valid, or whether it needs to be 194 /// treated as homeless for the purpose of future expressions. 195 /// 196 /// @return 197 /// A Process::Execution results value. 198 //------------------------------------------------------------------ 199 bool 200 FinalizeJITExecution (Stream &error_stream, 201 ExecutionContext &exe_ctx, 202 lldb::ClangExpressionVariableSP &result, 203 lldb::addr_t function_stack_bottom = LLDB_INVALID_ADDRESS, 204 lldb::addr_t function_stack_top = LLDB_INVALID_ADDRESS); 205 206 //------------------------------------------------------------------ 207 /// Return the string that the parser should parse. Must be a full 208 /// translation unit. 209 //------------------------------------------------------------------ 210 const char * Text()211 Text () 212 { 213 return m_transformed_text.c_str(); 214 } 215 216 //------------------------------------------------------------------ 217 /// Return the string that the user typed. 218 //------------------------------------------------------------------ 219 const char * GetUserText()220 GetUserText () 221 { 222 return m_expr_text.c_str(); 223 } 224 225 //------------------------------------------------------------------ 226 /// Return the function name that should be used for executing the 227 /// expression. Text() should contain the definition of this 228 /// function. 229 //------------------------------------------------------------------ 230 const char * FunctionName()231 FunctionName () 232 { 233 return "$__lldb_expr"; 234 } 235 236 //------------------------------------------------------------------ 237 /// Return the language that should be used when parsing. To use 238 /// the default, return eLanguageTypeUnknown. 239 //------------------------------------------------------------------ 240 virtual lldb::LanguageType Language()241 Language () 242 { 243 return m_language; 244 } 245 246 //------------------------------------------------------------------ 247 /// Return the object that the parser should use when resolving external 248 /// values. May be NULL if everything should be self-contained. 249 //------------------------------------------------------------------ 250 ClangExpressionDeclMap * DeclMap()251 DeclMap () 252 { 253 return m_expr_decl_map.get(); 254 } 255 256 //------------------------------------------------------------------ 257 /// Return the object that the parser should allow to access ASTs. 258 /// May be NULL if the ASTs do not need to be transformed. 259 /// 260 /// @param[in] passthrough 261 /// The ASTConsumer that the returned transformer should send 262 /// the ASTs to after transformation. 263 //------------------------------------------------------------------ 264 clang::ASTConsumer * 265 ASTTransformer (clang::ASTConsumer *passthrough); 266 267 //------------------------------------------------------------------ 268 /// Return the desired result type of the function, or 269 /// eResultTypeAny if indifferent. 270 //------------------------------------------------------------------ 271 virtual ResultType DesiredResultType()272 DesiredResultType () 273 { 274 return m_desired_type; 275 } 276 277 //------------------------------------------------------------------ 278 /// Return true if validation code should be inserted into the 279 /// expression. 280 //------------------------------------------------------------------ 281 bool NeedsValidation()282 NeedsValidation () 283 { 284 return true; 285 } 286 287 //------------------------------------------------------------------ 288 /// Return true if external variables in the expression should be 289 /// resolved. 290 //------------------------------------------------------------------ 291 bool NeedsVariableResolution()292 NeedsVariableResolution () 293 { 294 return true; 295 } 296 297 //------------------------------------------------------------------ 298 /// Evaluate one expression and return its result. 299 /// 300 /// @param[in] exe_ctx 301 /// The execution context to use when evaluating the expression. 302 /// 303 /// @param[in] execution_policy 304 /// Determines whether or not to try using the IR interpreter to 305 /// avoid running the expression on the parser. 306 /// 307 /// @param[in] language 308 /// If not eLanguageTypeUnknown, a language to use when parsing 309 /// the expression. Currently restricted to those languages 310 /// supported by Clang. 311 /// 312 /// @param[in] unwind_on_error 313 /// True if the thread's state should be restored in the case 314 /// of an error. 315 /// 316 /// @param[in] ignore_breakpoints 317 /// If true, ignore breakpoints while executing the expression. 318 /// 319 /// @param[in] result_type 320 /// If not eResultTypeAny, the type of the desired result. Will 321 /// result in parse errors if impossible. 322 /// 323 /// @param[in] expr_cstr 324 /// A C string containing the expression to be evaluated. 325 /// 326 /// @param[in] expr_prefix 327 /// If non-NULL, a C string containing translation-unit level 328 /// definitions to be included when the expression is parsed. 329 /// 330 /// @param[in/out] result_valobj_sp 331 /// If execution is successful, the result valobj is placed here. 332 /// 333 /// @param[in] try_all_threads 334 /// If true, then we will try to run all threads if the function doesn't complete on 335 /// one thread. See timeout_usec for the interaction of this variable and 336 /// the timeout. 337 /// 338 /// @param[in] timeout_usec 339 /// Timeout value (0 for no timeout). If try_all_threads is true, then we 340 /// will try on one thread for the lesser of .25 sec and half the total timeout. 341 /// then switch to running all threads, otherwise this will be the total timeout. 342 /// 343 /// @result 344 /// A Process::ExecutionResults value. eExecutionCompleted for success. 345 //------------------------------------------------------------------ 346 static ExecutionResults 347 Evaluate (ExecutionContext &exe_ctx, 348 lldb_private::ExecutionPolicy execution_policy, 349 lldb::LanguageType language, 350 ResultType desired_type, 351 bool unwind_on_error, 352 bool ignore_breakpoints, 353 const char *expr_cstr, 354 const char *expr_prefix, 355 lldb::ValueObjectSP &result_valobj_sp, 356 bool try_all_threads, 357 uint32_t timeout_usec); 358 359 static ExecutionResults 360 EvaluateWithError (ExecutionContext &exe_ctx, 361 lldb_private::ExecutionPolicy execution_policy, 362 lldb::LanguageType language, 363 ResultType desired_type, 364 bool unwind_on_error, 365 bool ignore_breakpoints, 366 const char *expr_cstr, 367 const char *expr_prefix, 368 lldb::ValueObjectSP &result_valobj_sp, 369 Error &error, 370 bool try_all_threads, 371 uint32_t timeout_usec); 372 373 static const Error::ValueType kNoResult = 0x1001; ///< ValueObject::GetError() returns this if there is no result from the expression. 374 private: 375 //------------------------------------------------------------------ 376 /// Populate m_cplusplus and m_objetivec based on the environment. 377 //------------------------------------------------------------------ 378 379 void 380 ScanContext (ExecutionContext &exe_ctx, 381 lldb_private::Error &err); 382 383 bool 384 PrepareToExecuteJITExpression (Stream &error_stream, 385 ExecutionContext &exe_ctx, 386 lldb::addr_t &struct_address, 387 lldb::addr_t &object_ptr, 388 lldb::addr_t &cmd_ptr); 389 390 void 391 InstallContext (ExecutionContext &exe_ctx); 392 393 bool 394 LockAndCheckContext (ExecutionContext &exe_ctx, 395 lldb::TargetSP &target_sp, 396 lldb::ProcessSP &process_sp, 397 lldb::StackFrameSP &frame_sp); 398 399 lldb::ProcessWP m_process_wp; ///< The process used as the context for the expression. 400 Address m_address; ///< The address the process is stopped in. 401 lldb::addr_t m_stack_frame_bottom; ///< The bottom of the allocated stack frame. 402 lldb::addr_t m_stack_frame_top; ///< The top of the allocated stack frame. 403 404 std::string m_expr_text; ///< The text of the expression, as typed by the user 405 std::string m_expr_prefix; ///< The text of the translation-level definitions, as provided by the user 406 lldb::LanguageType m_language; ///< The language to use when parsing (eLanguageTypeUnknown means use defaults) 407 bool m_allow_cxx; ///< True if the language allows C++. 408 bool m_allow_objc; ///< True if the language allows Objective-C. 409 std::string m_transformed_text; ///< The text of the expression, as send to the parser 410 ResultType m_desired_type; ///< The type to coerce the expression's result to. If eResultTypeAny, inferred from the expression. 411 412 std::unique_ptr<ClangExpressionDeclMap> m_expr_decl_map; ///< The map to use when parsing the expression. 413 std::unique_ptr<IRExecutionUnit> m_execution_unit_ap; ///< The execution unit the expression is stored in. 414 std::unique_ptr<Materializer> m_materializer_ap; ///< The materializer to use when running the expression. 415 std::unique_ptr<ASTResultSynthesizer> m_result_synthesizer; ///< The result synthesizer, if one is needed. 416 417 bool m_enforce_valid_object; ///< True if the expression parser should enforce the presence of a valid class pointer in order to generate the expression as a method. 418 bool m_cplusplus; ///< True if the expression is compiled as a C++ member function (true if it was parsed when exe_ctx was in a C++ method). 419 bool m_objectivec; ///< True if the expression is compiled as an Objective-C method (true if it was parsed when exe_ctx was in an Objective-C method). 420 bool m_static_method; ///< True if the expression is compiled as a static (or class) method (currently true if it was parsed when exe_ctx was in an Objective-C class method). 421 bool m_needs_object_ptr; ///< True if "this" or "self" must be looked up and passed in. False if the expression doesn't really use them and they can be NULL. 422 bool m_const_object; ///< True if "this" is const. 423 Target *m_target; ///< The target for storing persistent data like types and variables. 424 425 bool m_can_interpret; ///< True if the expression could be evaluated statically; false otherwise. 426 lldb::addr_t m_materialized_address; ///< The address at which the arguments to the expression have been materialized. 427 Materializer::DematerializerSP m_dematerializer_sp; ///< The dematerializer. 428 }; 429 430 } // namespace lldb_private 431 432 #endif // liblldb_ClangUserExpression_h_ 433