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_sepcification or DW_AT_abstract_origin 245 /// references if necessary. Returns null if no name is found. 246 const char *getName(DINameKind Kind) const; 247 248 /// Returns the declaration line (start line) for a DIE, assuming it specifies 249 /// a subprogram. This may be fetched from specification or abstract origin 250 /// for this subprogram by resolving DW_AT_sepcification or 251 /// DW_AT_abstract_origin references if necessary. 252 uint64_t getDeclLine() const; 253 254 /// Retrieves values of DW_AT_call_file, DW_AT_call_line and DW_AT_call_column 255 /// from DIE (or zeroes if they are missing). This function looks for 256 /// DW_AT_call attributes in this DIE only, it will not resolve the attribute 257 /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs. 258 /// \param CallFile filled in with non-zero if successful, zero if there is no 259 /// DW_AT_call_file attribute in this DIE. 260 /// \param CallLine filled in with non-zero if successful, zero if there is no 261 /// DW_AT_call_line attribute in this DIE. 262 /// \param CallColumn filled in with non-zero if successful, zero if there is 263 /// no DW_AT_call_column attribute in this DIE. 264 /// \param CallDiscriminator filled in with non-zero if successful, zero if 265 /// there is no DW_AT_GNU_discriminator attribute in this DIE. 266 void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine, 267 uint32_t &CallColumn, uint32_t &CallDiscriminator) const; 268 269 class attribute_iterator; 270 271 /// Get an iterator range to all attributes in the current DIE only. 272 /// 273 /// \returns an iterator range for the attributes of the current DIE. 274 iterator_range<attribute_iterator> attributes() const; 275 276 class iterator; 277 278 iterator begin() const; 279 iterator end() const; 280 281 std::reverse_iterator<iterator> rbegin() const; 282 std::reverse_iterator<iterator> rend() const; 283 284 iterator_range<iterator> children() const; 285 }; 286 287 class DWARFDie::attribute_iterator 288 : public iterator_facade_base<attribute_iterator, std::forward_iterator_tag, 289 const DWARFAttribute> { 290 /// The DWARF DIE we are extracting attributes from. 291 DWARFDie Die; 292 /// The value vended to clients via the operator*() or operator->(). 293 DWARFAttribute AttrValue; 294 /// The attribute index within the abbreviation declaration in Die. 295 uint32_t Index; 296 297 friend bool operator==(const attribute_iterator &LHS, 298 const attribute_iterator &RHS); 299 300 /// Update the attribute index and attempt to read the attribute value. If the 301 /// attribute is able to be read, update AttrValue and the Index member 302 /// variable. If the attribute value is not able to be read, an appropriate 303 /// error will be set if the Err member variable is non-NULL and the iterator 304 /// will be set to the end value so iteration stops. 305 void updateForIndex(const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I); 306 307 public: 308 attribute_iterator() = delete; 309 explicit attribute_iterator(DWARFDie D, bool End); 310 311 attribute_iterator &operator++(); 312 attribute_iterator &operator--(); 313 explicit operator bool() const { return AttrValue.isValid(); } 314 const DWARFAttribute &operator*() const { return AttrValue; } 315 }; 316 317 inline bool operator==(const DWARFDie::attribute_iterator &LHS, 318 const DWARFDie::attribute_iterator &RHS) { 319 return LHS.Index == RHS.Index; 320 } 321 322 inline bool operator!=(const DWARFDie::attribute_iterator &LHS, 323 const DWARFDie::attribute_iterator &RHS) { 324 return !(LHS == RHS); 325 } 326 327 inline bool operator==(const DWARFDie &LHS, const DWARFDie &RHS) { 328 return LHS.getDebugInfoEntry() == RHS.getDebugInfoEntry() && 329 LHS.getDwarfUnit() == RHS.getDwarfUnit(); 330 } 331 332 inline bool operator!=(const DWARFDie &LHS, const DWARFDie &RHS) { 333 return !(LHS == RHS); 334 } 335 336 inline bool operator<(const DWARFDie &LHS, const DWARFDie &RHS) { 337 return LHS.getOffset() < RHS.getOffset(); 338 } 339 340 class DWARFDie::iterator 341 : public iterator_facade_base<iterator, std::bidirectional_iterator_tag, 342 const DWARFDie> { 343 DWARFDie Die; 344 345 friend std::reverse_iterator<llvm::DWARFDie::iterator>; 346 friend bool operator==(const DWARFDie::iterator &LHS, 347 const DWARFDie::iterator &RHS); 348 349 public: 350 iterator() = default; 351 352 explicit iterator(DWARFDie D) : Die(D) {} 353 354 iterator &operator++() { 355 Die = Die.getSibling(); 356 return *this; 357 } 358 359 iterator &operator--() { 360 Die = Die.getPreviousSibling(); 361 return *this; 362 } 363 364 const DWARFDie &operator*() const { return Die; } 365 }; 366 367 inline bool operator==(const DWARFDie::iterator &LHS, 368 const DWARFDie::iterator &RHS) { 369 return LHS.Die == RHS.Die; 370 } 371 372 inline bool operator!=(const DWARFDie::iterator &LHS, 373 const DWARFDie::iterator &RHS) { 374 return !(LHS == RHS); 375 } 376 377 // These inline functions must follow the DWARFDie::iterator definition above 378 // as they use functions from that class. 379 inline DWARFDie::iterator DWARFDie::begin() const { 380 return iterator(getFirstChild()); 381 } 382 383 inline DWARFDie::iterator DWARFDie::end() const { 384 return iterator(getLastChild()); 385 } 386 387 inline iterator_range<DWARFDie::iterator> DWARFDie::children() const { 388 return make_range(begin(), end()); 389 } 390 391 } // end namespace llvm 392 393 namespace std { 394 395 template <> 396 class reverse_iterator<llvm::DWARFDie::iterator> 397 : public llvm::iterator_facade_base< 398 reverse_iterator<llvm::DWARFDie::iterator>, 399 bidirectional_iterator_tag, const llvm::DWARFDie> { 400 401 private: 402 llvm::DWARFDie Die; 403 bool AtEnd; 404 405 public: 406 reverse_iterator(llvm::DWARFDie::iterator It) 407 : Die(It.Die), AtEnd(!It.Die.getPreviousSibling()) { 408 if (!AtEnd) 409 Die = Die.getPreviousSibling(); 410 } 411 412 llvm::DWARFDie::iterator base() const { 413 return llvm::DWARFDie::iterator(AtEnd ? Die : Die.getSibling()); 414 } 415 416 reverse_iterator<llvm::DWARFDie::iterator> &operator++() { 417 assert(!AtEnd && "Incrementing rend"); 418 llvm::DWARFDie D = Die.getPreviousSibling(); 419 if (D) 420 Die = D; 421 else 422 AtEnd = true; 423 return *this; 424 } 425 426 reverse_iterator<llvm::DWARFDie::iterator> &operator--() { 427 if (AtEnd) { 428 AtEnd = false; 429 return *this; 430 } 431 Die = Die.getSibling(); 432 assert(!Die.isNULL() && "Decrementing rbegin"); 433 return *this; 434 } 435 436 const llvm::DWARFDie &operator*() const { 437 assert(Die.isValid()); 438 return Die; 439 } 440 441 // FIXME: We should be able to specify the equals operator as a friend, but 442 // that causes the compiler to think the operator overload is ambiguous 443 // with the friend declaration and the actual definition as candidates. 444 bool equals(const reverse_iterator<llvm::DWARFDie::iterator> &RHS) const { 445 return Die == RHS.Die && AtEnd == RHS.AtEnd; 446 } 447 }; 448 449 } // namespace std 450 451 namespace llvm { 452 453 inline bool operator==(const std::reverse_iterator<DWARFDie::iterator> &LHS, 454 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 455 return LHS.equals(RHS); 456 } 457 458 inline bool operator!=(const std::reverse_iterator<DWARFDie::iterator> &LHS, 459 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 460 return !(LHS == RHS); 461 } 462 463 inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rbegin() const { 464 return llvm::make_reverse_iterator(end()); 465 } 466 467 inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rend() const { 468 return llvm::make_reverse_iterator(begin()); 469 } 470 471 } // end namespace llvm 472 473 #endif // LLVM_DEBUGINFO_DWARFDIE_H 474