1 //===- DWARFDie.h -----------------------------------------------*- C++ -*-===// 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 #ifndef LLVM_DEBUGINFO_DWARFDIE_H 10 #define LLVM_DEBUGINFO_DWARFDIE_H 11 12 #include "llvm/ADT/ArrayRef.h" 13 #include "llvm/ADT/Optional.h" 14 #include "llvm/ADT/iterator.h" 15 #include "llvm/ADT/iterator_range.h" 16 #include "llvm/BinaryFormat/Dwarf.h" 17 #include "llvm/DebugInfo/DIContext.h" 18 #include "llvm/DebugInfo/DWARF/DWARFAddressRange.h" 19 #include "llvm/DebugInfo/DWARF/DWARFAttribute.h" 20 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h" 21 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.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 uint64_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 DWARFDie getAttributeValueAsReferencedDie(const DWARFFormValue &V) const; 184 185 /// Extract the range base attribute from this DIE as absolute section offset. 186 /// 187 /// This is a utility function that checks for either the DW_AT_rnglists_base 188 /// or DW_AT_GNU_ranges_base attribute. 189 /// 190 /// \returns anm optional absolute section offset value for the attribute. 191 Optional<uint64_t> getRangesBaseAttribute() const; 192 Optional<uint64_t> getLocBaseAttribute() const; 193 194 /// Get the DW_AT_high_pc attribute value as an address. 195 /// 196 /// In DWARF version 4 and later the high PC can be encoded as an offset from 197 /// the DW_AT_low_pc. This function takes care of extracting the value as an 198 /// address or offset and adds it to the low PC if needed and returns the 199 /// value as an optional in case the DIE doesn't have a DW_AT_high_pc 200 /// attribute. 201 /// 202 /// \param LowPC the low PC that might be needed to calculate the high PC. 203 /// \returns an optional address value for the attribute. 204 Optional<uint64_t> getHighPC(uint64_t LowPC) const; 205 206 /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU. 207 /// Returns true if both attributes are present. 208 bool getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC, 209 uint64_t &SectionIndex) const; 210 211 /// Get the address ranges for this DIE. 212 /// 213 /// Get the hi/low PC range if both attributes are available or exrtracts the 214 /// non-contiguous address ranges from the DW_AT_ranges attribute. 215 /// 216 /// Extracts the range information from this DIE only. This call doesn't look 217 /// for the range in any DW_AT_specification or DW_AT_abstract_origin DIEs. 218 /// 219 /// \returns a address range vector that might be empty if no address range 220 /// information is available. 221 Expected<DWARFAddressRangesVector> getAddressRanges() const; 222 223 /// Get all address ranges for any DW_TAG_subprogram DIEs in this DIE or any 224 /// of its children. 225 /// 226 /// Get the hi/low PC range if both attributes are available or exrtracts the 227 /// non-contiguous address ranges from the DW_AT_ranges attribute for this DIE 228 /// and all children. 229 /// 230 /// \param Ranges the addres range vector to fill in. 231 void collectChildrenAddressRanges(DWARFAddressRangesVector &Ranges) const; 232 233 bool addressRangeContainsAddress(const uint64_t Address) const; 234 235 Expected<DWARFLocationExpressionsVector> 236 getLocations(dwarf::Attribute Attr) const; 237 238 /// If a DIE represents a subprogram (or inlined subroutine), returns its 239 /// mangled name (or short name, if mangled is missing). This name may be 240 /// fetched from specification or abstract origin for this subprogram. 241 /// Returns null if no name is found. 242 const char *getSubroutineName(DINameKind Kind) const; 243 244 /// Return the DIE name resolving DW_AT_specification or DW_AT_abstract_origin 245 /// references if necessary. For the LinkageName case it additionaly searches 246 /// for ShortName if LinkageName is not found. 247 /// Returns null if no name is found. 248 const char *getName(DINameKind Kind) const; 249 250 /// Return the DIE short name resolving DW_AT_specification or 251 /// DW_AT_abstract_origin references if necessary. Returns null if no name 252 /// is found. 253 const char *getShortName() const; 254 255 /// Return the DIE linkage name resolving DW_AT_specification or 256 /// DW_AT_abstract_origin references if necessary. Returns null if no name 257 /// is found. 258 const char *getLinkageName() const; 259 260 /// Returns the declaration line (start line) for a DIE, assuming it specifies 261 /// a subprogram. This may be fetched from specification or abstract origin 262 /// for this subprogram by resolving DW_AT_sepcification or 263 /// DW_AT_abstract_origin references if necessary. 264 uint64_t getDeclLine() const; 265 std::string getDeclFile(DILineInfoSpecifier::FileLineInfoKind Kind) const; 266 267 /// Retrieves values of DW_AT_call_file, DW_AT_call_line and DW_AT_call_column 268 /// from DIE (or zeroes if they are missing). This function looks for 269 /// DW_AT_call attributes in this DIE only, it will not resolve the attribute 270 /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs. 271 /// \param CallFile filled in with non-zero if successful, zero if there is no 272 /// DW_AT_call_file attribute in this DIE. 273 /// \param CallLine filled in with non-zero if successful, zero if there is no 274 /// DW_AT_call_line attribute in this DIE. 275 /// \param CallColumn filled in with non-zero if successful, zero if there is 276 /// no DW_AT_call_column attribute in this DIE. 277 /// \param CallDiscriminator filled in with non-zero if successful, zero if 278 /// there is no DW_AT_GNU_discriminator attribute in this DIE. 279 void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine, 280 uint32_t &CallColumn, uint32_t &CallDiscriminator) const; 281 282 class attribute_iterator; 283 284 /// Get an iterator range to all attributes in the current DIE only. 285 /// 286 /// \returns an iterator range for the attributes of the current DIE. 287 iterator_range<attribute_iterator> attributes() const; 288 289 class iterator; 290 291 iterator begin() const; 292 iterator end() const; 293 294 std::reverse_iterator<iterator> rbegin() const; 295 std::reverse_iterator<iterator> rend() const; 296 297 iterator_range<iterator> children() const; 298 }; 299 300 class DWARFDie::attribute_iterator 301 : public iterator_facade_base<attribute_iterator, std::forward_iterator_tag, 302 const DWARFAttribute> { 303 /// The DWARF DIE we are extracting attributes from. 304 DWARFDie Die; 305 /// The value vended to clients via the operator*() or operator->(). 306 DWARFAttribute AttrValue; 307 /// The attribute index within the abbreviation declaration in Die. 308 uint32_t Index; 309 310 friend bool operator==(const attribute_iterator &LHS, 311 const attribute_iterator &RHS); 312 313 /// Update the attribute index and attempt to read the attribute value. If the 314 /// attribute is able to be read, update AttrValue and the Index member 315 /// variable. If the attribute value is not able to be read, an appropriate 316 /// error will be set if the Err member variable is non-NULL and the iterator 317 /// will be set to the end value so iteration stops. 318 void updateForIndex(const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I); 319 320 public: 321 attribute_iterator() = delete; 322 explicit attribute_iterator(DWARFDie D, bool End); 323 324 attribute_iterator &operator++(); 325 attribute_iterator &operator--(); 326 explicit operator bool() const { return AttrValue.isValid(); } 327 const DWARFAttribute &operator*() const { return AttrValue; } 328 }; 329 330 inline bool operator==(const DWARFDie::attribute_iterator &LHS, 331 const DWARFDie::attribute_iterator &RHS) { 332 return LHS.Index == RHS.Index; 333 } 334 335 inline bool operator!=(const DWARFDie::attribute_iterator &LHS, 336 const DWARFDie::attribute_iterator &RHS) { 337 return !(LHS == RHS); 338 } 339 340 inline bool operator==(const DWARFDie &LHS, const DWARFDie &RHS) { 341 return LHS.getDebugInfoEntry() == RHS.getDebugInfoEntry() && 342 LHS.getDwarfUnit() == RHS.getDwarfUnit(); 343 } 344 345 inline bool operator!=(const DWARFDie &LHS, const DWARFDie &RHS) { 346 return !(LHS == RHS); 347 } 348 349 inline bool operator<(const DWARFDie &LHS, const DWARFDie &RHS) { 350 return LHS.getOffset() < RHS.getOffset(); 351 } 352 353 class DWARFDie::iterator 354 : public iterator_facade_base<iterator, std::bidirectional_iterator_tag, 355 const DWARFDie> { 356 DWARFDie Die; 357 358 friend std::reverse_iterator<llvm::DWARFDie::iterator>; 359 friend bool operator==(const DWARFDie::iterator &LHS, 360 const DWARFDie::iterator &RHS); 361 362 public: 363 iterator() = default; 364 365 explicit iterator(DWARFDie D) : Die(D) {} 366 367 iterator &operator++() { 368 Die = Die.getSibling(); 369 return *this; 370 } 371 372 iterator &operator--() { 373 Die = Die.getPreviousSibling(); 374 return *this; 375 } 376 377 const DWARFDie &operator*() const { return Die; } 378 }; 379 380 inline bool operator==(const DWARFDie::iterator &LHS, 381 const DWARFDie::iterator &RHS) { 382 return LHS.Die == RHS.Die; 383 } 384 385 // These inline functions must follow the DWARFDie::iterator definition above 386 // as they use functions from that class. 387 inline DWARFDie::iterator DWARFDie::begin() const { 388 return iterator(getFirstChild()); 389 } 390 391 inline DWARFDie::iterator DWARFDie::end() const { 392 return iterator(getLastChild()); 393 } 394 395 inline iterator_range<DWARFDie::iterator> DWARFDie::children() const { 396 return make_range(begin(), end()); 397 } 398 399 } // end namespace llvm 400 401 namespace std { 402 403 template <> 404 class reverse_iterator<llvm::DWARFDie::iterator> 405 : public llvm::iterator_facade_base< 406 reverse_iterator<llvm::DWARFDie::iterator>, 407 bidirectional_iterator_tag, const llvm::DWARFDie> { 408 409 private: 410 llvm::DWARFDie Die; 411 bool AtEnd; 412 413 public: 414 reverse_iterator(llvm::DWARFDie::iterator It) 415 : Die(It.Die), AtEnd(!It.Die.getPreviousSibling()) { 416 if (!AtEnd) 417 Die = Die.getPreviousSibling(); 418 } 419 420 llvm::DWARFDie::iterator base() const { 421 return llvm::DWARFDie::iterator(AtEnd ? Die : Die.getSibling()); 422 } 423 424 reverse_iterator<llvm::DWARFDie::iterator> &operator++() { 425 assert(!AtEnd && "Incrementing rend"); 426 llvm::DWARFDie D = Die.getPreviousSibling(); 427 if (D) 428 Die = D; 429 else 430 AtEnd = true; 431 return *this; 432 } 433 434 reverse_iterator<llvm::DWARFDie::iterator> &operator--() { 435 if (AtEnd) { 436 AtEnd = false; 437 return *this; 438 } 439 Die = Die.getSibling(); 440 assert(!Die.isNULL() && "Decrementing rbegin"); 441 return *this; 442 } 443 444 const llvm::DWARFDie &operator*() const { 445 assert(Die.isValid()); 446 return Die; 447 } 448 449 // FIXME: We should be able to specify the equals operator as a friend, but 450 // that causes the compiler to think the operator overload is ambiguous 451 // with the friend declaration and the actual definition as candidates. 452 bool equals(const reverse_iterator<llvm::DWARFDie::iterator> &RHS) const { 453 return Die == RHS.Die && AtEnd == RHS.AtEnd; 454 } 455 }; 456 457 } // namespace std 458 459 namespace llvm { 460 461 inline bool operator==(const std::reverse_iterator<DWARFDie::iterator> &LHS, 462 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 463 return LHS.equals(RHS); 464 } 465 466 inline bool operator!=(const std::reverse_iterator<DWARFDie::iterator> &LHS, 467 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 468 return !(LHS == RHS); 469 } 470 471 inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rbegin() const { 472 return llvm::make_reverse_iterator(end()); 473 } 474 475 inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rend() const { 476 return llvm::make_reverse_iterator(begin()); 477 } 478 479 } // end namespace llvm 480 481 #endif // LLVM_DEBUGINFO_DWARFDIE_H 482