1 //===- DWARFDie.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 LLVM_DEBUGINFO_DWARFDIE_H 11 #define LLVM_DEBUGINFO_DWARFDIE_H 12 13 #include "llvm/ADT/ArrayRef.h" 14 #include "llvm/ADT/Optional.h" 15 #include "llvm/ADT/iterator.h" 16 #include "llvm/ADT/iterator_range.h" 17 #include "llvm/BinaryFormat/Dwarf.h" 18 #include "llvm/DebugInfo/DIContext.h" 19 #include "llvm/DebugInfo/DWARF/DWARFAddressRange.h" 20 #include "llvm/DebugInfo/DWARF/DWARFAttribute.h" 21 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h" 22 #include <cassert> 23 #include <cstdint> 24 #include <iterator> 25 26 namespace llvm { 27 28 class DWARFUnit; 29 class raw_ostream; 30 31 //===----------------------------------------------------------------------===// 32 /// Utility class that carries the DWARF compile/type unit and the debug info 33 /// entry in an object. 34 /// 35 /// When accessing information from a debug info entry we always need to DWARF 36 /// compile/type unit in order to extract the info correctly as some information 37 /// is relative to the compile/type unit. Prior to this class the DWARFUnit and 38 /// the DWARFDebugInfoEntry was passed around separately and there was the 39 /// possibility for error if the wrong DWARFUnit was used to extract a unit 40 /// relative offset. This class helps to ensure that this doesn't happen and 41 /// also simplifies the attribute extraction calls by not having to specify the 42 /// DWARFUnit for each call. 43 class DWARFDie { 44 DWARFUnit *U = nullptr; 45 const DWARFDebugInfoEntry *Die = nullptr; 46 47 public: 48 DWARFDie() = default; 49 DWARFDie(DWARFUnit *Unit, const DWARFDebugInfoEntry *D) : U(Unit), Die(D) {} 50 51 bool isValid() const { return U && Die; } 52 explicit operator bool() const { return isValid(); } 53 const DWARFDebugInfoEntry *getDebugInfoEntry() const { return Die; } 54 DWARFUnit *getDwarfUnit() const { return U; } 55 56 /// Get the abbreviation declaration for this DIE. 57 /// 58 /// \returns the abbreviation declaration or NULL for null tags. 59 const DWARFAbbreviationDeclaration *getAbbreviationDeclarationPtr() const { 60 assert(isValid() && "must check validity prior to calling"); 61 return Die->getAbbreviationDeclarationPtr(); 62 } 63 64 /// Get the absolute offset into the debug info or types section. 65 /// 66 /// \returns the DIE offset or -1U if invalid. 67 uint32_t getOffset() const { 68 assert(isValid() && "must check validity prior to calling"); 69 return Die->getOffset(); 70 } 71 72 dwarf::Tag getTag() const { 73 auto AbbrevDecl = getAbbreviationDeclarationPtr(); 74 if (AbbrevDecl) 75 return AbbrevDecl->getTag(); 76 return dwarf::DW_TAG_null; 77 } 78 79 bool hasChildren() const { 80 assert(isValid() && "must check validity prior to calling"); 81 return Die->hasChildren(); 82 } 83 84 /// Returns true for a valid DIE that terminates a sibling chain. 85 bool isNULL() const { return getAbbreviationDeclarationPtr() == nullptr; } 86 87 /// Returns true if DIE represents a subprogram (not inlined). 88 bool isSubprogramDIE() const; 89 90 /// Returns true if DIE represents a subprogram or an inlined subroutine. 91 bool isSubroutineDIE() const; 92 93 /// Get the parent of this DIE object. 94 /// 95 /// \returns a valid DWARFDie instance if this object has a parent or an 96 /// invalid DWARFDie instance if it doesn't. 97 DWARFDie getParent() const; 98 99 /// Get the sibling of this DIE object. 100 /// 101 /// \returns a valid DWARFDie instance if this object has a sibling or an 102 /// invalid DWARFDie instance if it doesn't. 103 DWARFDie getSibling() const; 104 105 /// Get the previous sibling of this DIE object. 106 /// 107 /// \returns a valid DWARFDie instance if this object has a sibling or an 108 /// invalid DWARFDie instance if it doesn't. 109 DWARFDie getPreviousSibling() const; 110 111 /// Get the first child of this DIE object. 112 /// 113 /// \returns a valid DWARFDie instance if this object has children or an 114 /// invalid DWARFDie instance if it doesn't. 115 DWARFDie getFirstChild() const; 116 117 /// Get the last child of this DIE object. 118 /// 119 /// \returns a valid null DWARFDie instance if this object has children or an 120 /// invalid DWARFDie instance if it doesn't. 121 DWARFDie getLastChild() const; 122 123 /// Dump the DIE and all of its attributes to the supplied stream. 124 /// 125 /// \param OS the stream to use for output. 126 /// \param indent the number of characters to indent each line that is output. 127 void dump(raw_ostream &OS, unsigned indent = 0, 128 DIDumpOptions DumpOpts = DIDumpOptions()) const; 129 130 /// Convenience zero-argument overload for debugging. 131 LLVM_DUMP_METHOD void dump() const; 132 133 /// Extract the specified attribute from this DIE. 134 /// 135 /// Extract an attribute value from this DIE only. This call doesn't look 136 /// for the attribute value in any DW_AT_specification or 137 /// DW_AT_abstract_origin referenced DIEs. 138 /// 139 /// \param Attr the attribute to extract. 140 /// \returns an optional DWARFFormValue that will have the form value if the 141 /// attribute was successfully extracted. 142 Optional<DWARFFormValue> find(dwarf::Attribute Attr) const; 143 144 /// Extract the first value of any attribute in Attrs from this DIE. 145 /// 146 /// Extract the first attribute that matches from this DIE only. This call 147 /// doesn't look for the attribute value in any DW_AT_specification or 148 /// DW_AT_abstract_origin referenced DIEs. The attributes will be searched 149 /// linearly in the order they are specified within Attrs. 150 /// 151 /// \param Attrs an array of DWARF attribute to look for. 152 /// \returns an optional that has a valid DWARFFormValue for the first 153 /// matching attribute in Attrs, or None if none of the attributes in Attrs 154 /// exist in this DIE. 155 Optional<DWARFFormValue> find(ArrayRef<dwarf::Attribute> Attrs) const; 156 157 /// Extract the first value of any attribute in Attrs from this DIE and 158 /// recurse into any DW_AT_specification or DW_AT_abstract_origin referenced 159 /// DIEs. 160 /// 161 /// \param Attrs an array of DWARF attribute to look for. 162 /// \returns an optional that has a valid DWARFFormValue for the first 163 /// matching attribute in Attrs, or None if none of the attributes in Attrs 164 /// exist in this DIE or in any DW_AT_specification or DW_AT_abstract_origin 165 /// DIEs. 166 Optional<DWARFFormValue> 167 findRecursively(ArrayRef<dwarf::Attribute> Attrs) const; 168 169 /// Extract the specified attribute from this DIE as the referenced DIE. 170 /// 171 /// Regardless of the reference type, return the correct DWARFDie instance if 172 /// the attribute exists. The returned DWARFDie object might be from another 173 /// DWARFUnit, but that is all encapsulated in the new DWARFDie object. 174 /// 175 /// Extract an attribute value from this DIE only. This call doesn't look 176 /// for the attribute value in any DW_AT_specification or 177 /// DW_AT_abstract_origin referenced DIEs. 178 /// 179 /// \param Attr the attribute to extract. 180 /// \returns a valid DWARFDie instance if the attribute exists, or an invalid 181 /// DWARFDie object if it doesn't. 182 DWARFDie getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const; 183 184 /// Extract the range base attribute from this DIE as absolute section offset. 185 /// 186 /// This is a utility function that checks for either the DW_AT_rnglists_base 187 /// or DW_AT_GNU_ranges_base attribute. 188 /// 189 /// \returns anm optional absolute section offset value for the attribute. 190 Optional<uint64_t> getRangesBaseAttribute() const; 191 192 /// Get the DW_AT_high_pc attribute value as an address. 193 /// 194 /// In DWARF version 4 and later the high PC can be encoded as an offset from 195 /// the DW_AT_low_pc. This function takes care of extracting the value as an 196 /// address or offset and adds it to the low PC if needed and returns the 197 /// value as an optional in case the DIE doesn't have a DW_AT_high_pc 198 /// attribute. 199 /// 200 /// \param LowPC the low PC that might be needed to calculate the high PC. 201 /// \returns an optional address value for the attribute. 202 Optional<uint64_t> getHighPC(uint64_t LowPC) const; 203 204 /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU. 205 /// Returns true if both attributes are present. 206 bool getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC, 207 uint64_t &SectionIndex) const; 208 209 /// Get the address ranges for this DIE. 210 /// 211 /// Get the hi/low PC range if both attributes are available or exrtracts the 212 /// non-contiguous address ranges from the DW_AT_ranges attribute. 213 /// 214 /// Extracts the range information from this DIE only. This call doesn't look 215 /// for the range in any DW_AT_specification or DW_AT_abstract_origin DIEs. 216 /// 217 /// \returns a address range vector that might be empty if no address range 218 /// information is available. 219 Expected<DWARFAddressRangesVector> getAddressRanges() const; 220 221 /// Get all address ranges for any DW_TAG_subprogram DIEs in this DIE or any 222 /// of its children. 223 /// 224 /// Get the hi/low PC range if both attributes are available or exrtracts the 225 /// non-contiguous address ranges from the DW_AT_ranges attribute for this DIE 226 /// and all children. 227 /// 228 /// \param Ranges the addres range vector to fill in. 229 void collectChildrenAddressRanges(DWARFAddressRangesVector &Ranges) const; 230 231 bool addressRangeContainsAddress(const uint64_t Address) const; 232 233 /// If a DIE represents a subprogram (or inlined subroutine), returns its 234 /// mangled name (or short name, if mangled is missing). This name may be 235 /// fetched from specification or abstract origin for this subprogram. 236 /// Returns null if no name is found. 237 const char *getSubroutineName(DINameKind Kind) const; 238 239 /// Return the DIE name resolving DW_AT_sepcification or DW_AT_abstract_origin 240 /// references if necessary. Returns null if no name is found. 241 const char *getName(DINameKind Kind) const; 242 243 /// Returns the declaration line (start line) for a DIE, assuming it specifies 244 /// a subprogram. This may be fetched from specification or abstract origin 245 /// for this subprogram by resolving DW_AT_sepcification or 246 /// DW_AT_abstract_origin references if necessary. 247 uint64_t getDeclLine() const; 248 249 /// Retrieves values of DW_AT_call_file, DW_AT_call_line and DW_AT_call_column 250 /// from DIE (or zeroes if they are missing). This function looks for 251 /// DW_AT_call attributes in this DIE only, it will not resolve the attribute 252 /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs. 253 /// \param CallFile filled in with non-zero if successful, zero if there is no 254 /// DW_AT_call_file attribute in this DIE. 255 /// \param CallLine filled in with non-zero if successful, zero if there is no 256 /// DW_AT_call_line attribute in this DIE. 257 /// \param CallColumn filled in with non-zero if successful, zero if there is 258 /// no DW_AT_call_column attribute in this DIE. 259 /// \param CallDiscriminator filled in with non-zero if successful, zero if 260 /// there is no DW_AT_GNU_discriminator attribute in this DIE. 261 void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine, 262 uint32_t &CallColumn, uint32_t &CallDiscriminator) const; 263 264 class attribute_iterator; 265 266 /// Get an iterator range to all attributes in the current DIE only. 267 /// 268 /// \returns an iterator range for the attributes of the current DIE. 269 iterator_range<attribute_iterator> attributes() const; 270 271 class iterator; 272 273 iterator begin() const; 274 iterator end() const; 275 276 std::reverse_iterator<iterator> rbegin() const; 277 std::reverse_iterator<iterator> rend() const; 278 279 iterator_range<iterator> children() const; 280 }; 281 282 class DWARFDie::attribute_iterator 283 : public iterator_facade_base<attribute_iterator, std::forward_iterator_tag, 284 const DWARFAttribute> { 285 /// The DWARF DIE we are extracting attributes from. 286 DWARFDie Die; 287 /// The value vended to clients via the operator*() or operator->(). 288 DWARFAttribute AttrValue; 289 /// The attribute index within the abbreviation declaration in Die. 290 uint32_t Index; 291 292 friend bool operator==(const attribute_iterator &LHS, 293 const attribute_iterator &RHS); 294 295 /// Update the attribute index and attempt to read the attribute value. If the 296 /// attribute is able to be read, update AttrValue and the Index member 297 /// variable. If the attribute value is not able to be read, an appropriate 298 /// error will be set if the Err member variable is non-NULL and the iterator 299 /// will be set to the end value so iteration stops. 300 void updateForIndex(const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I); 301 302 public: 303 attribute_iterator() = delete; 304 explicit attribute_iterator(DWARFDie D, bool End); 305 306 attribute_iterator &operator++(); 307 attribute_iterator &operator--(); 308 explicit operator bool() const { return AttrValue.isValid(); } 309 const DWARFAttribute &operator*() const { return AttrValue; } 310 }; 311 312 inline bool operator==(const DWARFDie::attribute_iterator &LHS, 313 const DWARFDie::attribute_iterator &RHS) { 314 return LHS.Index == RHS.Index; 315 } 316 317 inline bool operator!=(const DWARFDie::attribute_iterator &LHS, 318 const DWARFDie::attribute_iterator &RHS) { 319 return !(LHS == RHS); 320 } 321 322 inline bool operator==(const DWARFDie &LHS, const DWARFDie &RHS) { 323 return LHS.getDebugInfoEntry() == RHS.getDebugInfoEntry() && 324 LHS.getDwarfUnit() == RHS.getDwarfUnit(); 325 } 326 327 inline bool operator!=(const DWARFDie &LHS, const DWARFDie &RHS) { 328 return !(LHS == RHS); 329 } 330 331 inline bool operator<(const DWARFDie &LHS, const DWARFDie &RHS) { 332 return LHS.getOffset() < RHS.getOffset(); 333 } 334 335 class DWARFDie::iterator 336 : public iterator_facade_base<iterator, std::bidirectional_iterator_tag, 337 const DWARFDie> { 338 DWARFDie Die; 339 340 friend std::reverse_iterator<llvm::DWARFDie::iterator>; 341 friend bool operator==(const DWARFDie::iterator &LHS, 342 const DWARFDie::iterator &RHS); 343 344 public: 345 iterator() = default; 346 347 explicit iterator(DWARFDie D) : Die(D) {} 348 349 iterator &operator++() { 350 Die = Die.getSibling(); 351 return *this; 352 } 353 354 iterator &operator--() { 355 Die = Die.getPreviousSibling(); 356 return *this; 357 } 358 359 const DWARFDie &operator*() const { return Die; } 360 }; 361 362 inline bool operator==(const DWARFDie::iterator &LHS, 363 const DWARFDie::iterator &RHS) { 364 return LHS.Die == RHS.Die; 365 } 366 367 inline bool operator!=(const DWARFDie::iterator &LHS, 368 const DWARFDie::iterator &RHS) { 369 return !(LHS == RHS); 370 } 371 372 // These inline functions must follow the DWARFDie::iterator definition above 373 // as they use functions from that class. 374 inline DWARFDie::iterator DWARFDie::begin() const { 375 return iterator(getFirstChild()); 376 } 377 378 inline DWARFDie::iterator DWARFDie::end() const { 379 return iterator(getLastChild()); 380 } 381 382 inline iterator_range<DWARFDie::iterator> DWARFDie::children() const { 383 return make_range(begin(), end()); 384 } 385 386 } // end namespace llvm 387 388 namespace std { 389 390 template <> 391 class reverse_iterator<llvm::DWARFDie::iterator> 392 : public llvm::iterator_facade_base< 393 reverse_iterator<llvm::DWARFDie::iterator>, 394 bidirectional_iterator_tag, const llvm::DWARFDie> { 395 396 private: 397 llvm::DWARFDie Die; 398 bool AtEnd; 399 400 public: 401 reverse_iterator(llvm::DWARFDie::iterator It) 402 : Die(It.Die), AtEnd(!It.Die.getPreviousSibling()) { 403 if (!AtEnd) 404 Die = Die.getPreviousSibling(); 405 } 406 407 reverse_iterator<llvm::DWARFDie::iterator> &operator++() { 408 assert(!AtEnd && "Incrementing rend"); 409 llvm::DWARFDie D = Die.getPreviousSibling(); 410 if (D) 411 Die = D; 412 else 413 AtEnd = true; 414 return *this; 415 } 416 417 reverse_iterator<llvm::DWARFDie::iterator> &operator--() { 418 if (AtEnd) { 419 AtEnd = false; 420 return *this; 421 } 422 Die = Die.getSibling(); 423 assert(!Die.isNULL() && "Decrementing rbegin"); 424 return *this; 425 } 426 427 const llvm::DWARFDie &operator*() const { 428 assert(Die.isValid()); 429 return Die; 430 } 431 432 // FIXME: We should be able to specify the equals operator as a friend, but 433 // that causes the compiler to think the operator overload is ambiguous 434 // with the friend declaration and the actual definition as candidates. 435 bool equals(const reverse_iterator<llvm::DWARFDie::iterator> &RHS) const { 436 return Die == RHS.Die && AtEnd == RHS.AtEnd; 437 } 438 }; 439 440 } // namespace std 441 442 namespace llvm { 443 444 inline bool operator==(const std::reverse_iterator<DWARFDie::iterator> &LHS, 445 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 446 return LHS.equals(RHS); 447 } 448 449 inline bool operator!=(const std::reverse_iterator<DWARFDie::iterator> &LHS, 450 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 451 return !(LHS == RHS); 452 } 453 454 inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rbegin() const { 455 return llvm::make_reverse_iterator(end()); 456 } 457 458 inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rend() const { 459 return llvm::make_reverse_iterator(begin()); 460 } 461 462 } // end namespace llvm 463 464 #endif // LLVM_DEBUGINFO_DWARFDIE_H 465