FunctionCaller.h revision 296417
1//===-- FunctionCaller.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_FunctionCaller_h_ 11#define liblldb_FunctionCaller_h_ 12 13// C Includes 14// C++ Includes 15#include <list> 16#include <memory> 17#include <string> 18#include <vector> 19 20// Other libraries and framework includes 21// Project includes 22#include "lldb/Core/Address.h" 23#include "lldb/Core/Value.h" 24#include "lldb/Expression/Expression.h" 25#include "lldb/Expression/ExpressionParser.h" 26#include "lldb/Symbol/CompilerType.h" 27 28namespace lldb_private 29{ 30 31//---------------------------------------------------------------------- 32/// @class FunctionCaller FunctionCaller.h "lldb/Expression/FunctionCaller.h" 33/// @brief Encapsulates a function that can be called. 34/// 35/// A given FunctionCaller object can handle a single function signature. 36/// Once constructed, it can set up any number of concurrent calls to 37/// functions with that signature. 38/// 39/// It performs the call by synthesizing a structure that contains the pointer 40/// to the function and the arguments that should be passed to that function, 41/// and producing a special-purpose JIT-compiled function that accepts a void* 42/// pointing to this struct as its only argument and calls the function in the 43/// struct with the written arguments. This method lets Clang handle the 44/// vagaries of function calling conventions. 45/// 46/// The simplest use of the FunctionCaller is to construct it with a 47/// function representative of the signature you want to use, then call 48/// ExecuteFunction(ExecutionContext &, Stream &, Value &). 49/// 50/// If you need to reuse the arguments for several calls, you can call 51/// InsertFunction() followed by WriteFunctionArguments(), which will return 52/// the location of the args struct for the wrapper function in args_addr_ref. 53/// 54/// If you need to call the function on the thread plan stack, you can also 55/// call InsertFunction() followed by GetThreadPlanToCallFunction(). 56/// 57/// Any of the methods that take arg_addr_ptr or arg_addr_ref can be passed 58/// a pointer set to LLDB_INVALID_ADDRESS and new structure will be allocated 59/// and its address returned in that variable. 60/// 61/// Any of the methods that take arg_addr_ptr can be passed nullptr, and the 62/// argument space will be managed for you. 63//---------------------------------------------------------------------- 64class FunctionCaller : public Expression 65{ 66public: 67 //------------------------------------------------------------------ 68 /// Constructor 69 /// 70 /// @param[in] exe_scope 71 /// An execution context scope that gets us at least a target and 72 /// process. 73 /// 74 /// @param[in] ast_context 75 /// The AST context to evaluate argument types in. 76 /// 77 /// @param[in] return_qualtype 78 /// An opaque Clang QualType for the function result. Should be 79 /// defined in ast_context. 80 /// 81 /// @param[in] function_address 82 /// The address of the function to call. 83 /// 84 /// @param[in] arg_value_list 85 /// The default values to use when calling this function. Can 86 /// be overridden using WriteFunctionArguments(). 87 //------------------------------------------------------------------ 88 FunctionCaller (ExecutionContextScope &exe_scope, 89 const CompilerType &return_type, 90 const Address& function_address, 91 const ValueList &arg_value_list, 92 const char *name); 93 94 //------------------------------------------------------------------ 95 /// Destructor 96 //------------------------------------------------------------------ 97 ~FunctionCaller() override; 98 99 //------------------------------------------------------------------ 100 /// Compile the wrapper function 101 /// 102 /// @param[in] errors 103 /// The stream to print parser errors to. 104 /// 105 /// @return 106 /// The number of errors. 107 //------------------------------------------------------------------ 108 virtual unsigned 109 CompileFunction (Stream &errors) = 0; 110 111 //------------------------------------------------------------------ 112 /// Insert the default function wrapper and its default argument struct 113 /// 114 /// @param[in] exe_ctx 115 /// The execution context to insert the function and its arguments 116 /// into. 117 /// 118 /// @param[in,out] args_addr_ref 119 /// The address of the structure to write the arguments into. May 120 /// be LLDB_INVALID_ADDRESS; if it is, a new structure is allocated 121 /// and args_addr_ref is pointed to it. 122 /// 123 /// @param[in] errors 124 /// The stream to write errors to. 125 /// 126 /// @return 127 /// True on success; false otherwise. 128 //------------------------------------------------------------------ 129 bool 130 InsertFunction (ExecutionContext &exe_ctx, 131 lldb::addr_t &args_addr_ref, 132 Stream &errors); 133 134 //------------------------------------------------------------------ 135 /// Insert the default function wrapper (using the JIT) 136 /// 137 /// @param[in] exe_ctx 138 /// The execution context to insert the function and its arguments 139 /// into. 140 /// 141 /// @param[in] errors 142 /// The stream to write errors to. 143 /// 144 /// @return 145 /// True on success; false otherwise. 146 //------------------------------------------------------------------ 147 bool WriteFunctionWrapper (ExecutionContext &exe_ctx, 148 Stream &errors); 149 150 //------------------------------------------------------------------ 151 /// Insert the default function argument struct 152 /// 153 /// @param[in] exe_ctx 154 /// The execution context to insert the function and its arguments 155 /// into. 156 /// 157 /// @param[in,out] args_addr_ref 158 /// The address of the structure to write the arguments into. May 159 /// be LLDB_INVALID_ADDRESS; if it is, a new structure is allocated 160 /// and args_addr_ref is pointed to it. 161 /// 162 /// @param[in] errors 163 /// The stream to write errors to. 164 /// 165 /// @return 166 /// True on success; false otherwise. 167 //------------------------------------------------------------------ 168 bool WriteFunctionArguments (ExecutionContext &exe_ctx, 169 lldb::addr_t &args_addr_ref, 170 Stream &errors); 171 172 //------------------------------------------------------------------ 173 /// Insert an argument struct with a non-default function address and 174 /// non-default argument values 175 /// 176 /// @param[in] exe_ctx 177 /// The execution context to insert the function and its arguments 178 /// into. 179 /// 180 /// @param[in,out] args_addr_ref 181 /// The address of the structure to write the arguments into. May 182 /// be LLDB_INVALID_ADDRESS; if it is, a new structure is allocated 183 /// and args_addr_ref is pointed at it. 184 /// 185 /// @param[in] arg_values 186 /// The values of the function's arguments. 187 /// 188 /// @param[in] errors 189 /// The stream to write errors to. 190 /// 191 /// @return 192 /// True on success; false otherwise. 193 //------------------------------------------------------------------ 194 bool WriteFunctionArguments (ExecutionContext &exe_ctx, 195 lldb::addr_t &args_addr_ref, 196 ValueList &arg_values, 197 Stream &errors); 198 199 //------------------------------------------------------------------ 200 /// Run the function this FunctionCaller was created with. 201 /// 202 /// This is the full version. 203 /// 204 /// @param[in] exe_ctx 205 /// The thread & process in which this function will run. 206 /// 207 /// @param[in] args_addr_ptr 208 /// If nullptr, the function will take care of allocating & deallocating the wrapper 209 /// args structure. Otherwise, if set to LLDB_INVALID_ADDRESS, a new structure 210 /// will be allocated, filled and the address returned to you. You are responsible 211 /// for deallocating it. And if passed in with a value other than LLDB_INVALID_ADDRESS, 212 /// this should point to an already allocated structure with the values already written. 213 /// 214 /// @param[in] errors 215 /// Errors will be written here if there are any. 216 /// 217 /// @param[in] options 218 /// The options for this expression execution. 219 /// 220 /// @param[out] results 221 /// The result value will be put here after running the function. 222 /// 223 /// @return 224 /// Returns one of the ExpressionResults enum indicating function call status. 225 //------------------------------------------------------------------ 226 lldb::ExpressionResults 227 ExecuteFunction(ExecutionContext &exe_ctx, 228 lldb::addr_t *args_addr_ptr, 229 const EvaluateExpressionOptions &options, 230 Stream &errors, 231 Value &results); 232 233 //------------------------------------------------------------------ 234 /// Get a thread plan to run the function this FunctionCaller was created with. 235 /// 236 /// @param[in] exe_ctx 237 /// The execution context to insert the function and its arguments 238 /// into. 239 /// 240 /// @param[in] func_addr 241 /// The address of the function in the target process. 242 /// 243 /// @param[in] args_addr 244 /// The address of the argument struct. 245 /// 246 /// @param[in] errors 247 /// The stream to write errors to. 248 /// 249 /// @param[in] stop_others 250 /// True if other threads should pause during execution. 251 /// 252 /// @param[in] unwind_on_error 253 /// True if the thread plan may simply be discarded if an error occurs. 254 /// 255 /// @return 256 /// A ThreadPlan shared pointer for executing the function. 257 //------------------------------------------------------------------ 258 lldb::ThreadPlanSP 259 GetThreadPlanToCallFunction (ExecutionContext &exe_ctx, 260 lldb::addr_t args_addr, 261 const EvaluateExpressionOptions &options, 262 Stream &errors); 263 264 //------------------------------------------------------------------ 265 /// Get the result of the function from its struct 266 /// 267 /// @param[in] exe_ctx 268 /// The execution context to retrieve the result from. 269 /// 270 /// @param[in] args_addr 271 /// The address of the argument struct. 272 /// 273 /// @param[out] ret_value 274 /// The value returned by the function. 275 /// 276 /// @return 277 /// True on success; false otherwise. 278 //------------------------------------------------------------------ 279 bool FetchFunctionResults (ExecutionContext &exe_ctx, 280 lldb::addr_t args_addr, 281 Value &ret_value); 282 283 //------------------------------------------------------------------ 284 /// Deallocate the arguments structure 285 /// 286 /// @param[in] exe_ctx 287 /// The execution context to insert the function and its arguments 288 /// into. 289 /// 290 /// @param[in] args_addr 291 /// The address of the argument struct. 292 //------------------------------------------------------------------ 293 void DeallocateFunctionResults (ExecutionContext &exe_ctx, 294 lldb::addr_t args_addr); 295 296 //------------------------------------------------------------------ 297 /// Interface for ClangExpression 298 //------------------------------------------------------------------ 299 300 //------------------------------------------------------------------ 301 /// Return the string that the parser should parse. Must be a full 302 /// translation unit. 303 //------------------------------------------------------------------ 304 const char * 305 Text() override 306 { 307 return m_wrapper_function_text.c_str(); 308 } 309 310 //------------------------------------------------------------------ 311 /// Return the function name that should be used for executing the 312 /// expression. Text() should contain the definition of this 313 /// function. 314 //------------------------------------------------------------------ 315 const char * 316 FunctionName() override 317 { 318 return m_wrapper_function_name.c_str(); 319 } 320 321 //------------------------------------------------------------------ 322 /// Return the object that the parser should use when registering 323 /// local variables. May be nullptr if the Expression doesn't care. 324 //------------------------------------------------------------------ 325 ExpressionVariableList * 326 LocalVariables () 327 { 328 return nullptr; 329 } 330 331 //------------------------------------------------------------------ 332 /// Return true if validation code should be inserted into the 333 /// expression. 334 //------------------------------------------------------------------ 335 bool 336 NeedsValidation() override 337 { 338 return false; 339 } 340 341 //------------------------------------------------------------------ 342 /// Return true if external variables in the expression should be 343 /// resolved. 344 //------------------------------------------------------------------ 345 bool 346 NeedsVariableResolution() override 347 { 348 return false; 349 } 350 351 ValueList 352 GetArgumentValues () const 353 { 354 return m_arg_values; 355 } 356 357protected: 358 // Note: the parser needs to be destructed before the execution unit, so 359 // declare the execution unit first. 360 std::shared_ptr<IRExecutionUnit> m_execution_unit_sp; 361 std::unique_ptr<ExpressionParser> m_parser; ///< The parser responsible for compiling the function. 362 ///< This will get made in CompileFunction, so it is 363 ///< safe to access it after that. 364 365 lldb::ModuleWP m_jit_module_wp; 366 std::string m_name; ///< The name of this clang function - for debugging purposes. 367 368 Function *m_function_ptr; ///< The function we're going to call. May be nullptr if we don't have debug info for the function. 369 Address m_function_addr; ///< If we don't have the FunctionSP, we at least need the address & return type. 370 CompilerType m_function_return_type; ///< The opaque clang qual type for the function return type. 371 372 std::string m_wrapper_function_name; ///< The name of the wrapper function. 373 std::string m_wrapper_function_text; ///< The contents of the wrapper function. 374 std::string m_wrapper_struct_name; ///< The name of the struct that contains the target function address, arguments, and result. 375 std::list<lldb::addr_t> m_wrapper_args_addrs; ///< The addresses of the arguments to the wrapper function. 376 377 bool m_struct_valid; ///< True if the ASTStructExtractor has populated the variables below. 378 379 //------------------------------------------------------------------ 380 /// These values are populated by the ASTStructExtractor 381 size_t m_struct_size; ///< The size of the argument struct, in bytes. 382 std::vector<uint64_t> m_member_offsets; ///< The offset of each member in the struct, in bytes. 383 uint64_t m_return_size; ///< The size of the result variable, in bytes. 384 uint64_t m_return_offset; ///< The offset of the result variable in the struct, in bytes. 385 //------------------------------------------------------------------ 386 387 ValueList m_arg_values; ///< The default values of the arguments. 388 389 bool m_compiled; ///< True if the wrapper function has already been parsed. 390 bool m_JITted; ///< True if the wrapper function has already been JIT-compiled. 391}; 392 393} // namespace lldb_private 394 395#endif // liblldb_FunctionCaller_h_ 396