DWARFDie.h revision 344779
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 26namespace llvm { 27 28class DWARFUnit; 29class 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. 43class DWARFDie { 44 DWARFUnit *U = nullptr; 45 const DWARFDebugInfoEntry *Die = nullptr; 46 47public: 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 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; 192 193 /// Get the DW_AT_high_pc attribute value as an address. 194 /// 195 /// In DWARF version 4 and later the high PC can be encoded as an offset from 196 /// the DW_AT_low_pc. This function takes care of extracting the value as an 197 /// address or offset and adds it to the low PC if needed and returns the 198 /// value as an optional in case the DIE doesn't have a DW_AT_high_pc 199 /// attribute. 200 /// 201 /// \param LowPC the low PC that might be needed to calculate the high PC. 202 /// \returns an optional address value for the attribute. 203 Optional<uint64_t> getHighPC(uint64_t LowPC) const; 204 205 /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU. 206 /// Returns true if both attributes are present. 207 bool getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC, 208 uint64_t &SectionIndex) const; 209 210 /// Get the address ranges for this DIE. 211 /// 212 /// Get the hi/low PC range if both attributes are available or exrtracts the 213 /// non-contiguous address ranges from the DW_AT_ranges attribute. 214 /// 215 /// Extracts the range information from this DIE only. This call doesn't look 216 /// for the range in any DW_AT_specification or DW_AT_abstract_origin DIEs. 217 /// 218 /// \returns a address range vector that might be empty if no address range 219 /// information is available. 220 Expected<DWARFAddressRangesVector> getAddressRanges() const; 221 222 /// Get all address ranges for any DW_TAG_subprogram DIEs in this DIE or any 223 /// of its children. 224 /// 225 /// Get the hi/low PC range if both attributes are available or exrtracts the 226 /// non-contiguous address ranges from the DW_AT_ranges attribute for this DIE 227 /// and all children. 228 /// 229 /// \param Ranges the addres range vector to fill in. 230 void collectChildrenAddressRanges(DWARFAddressRangesVector &Ranges) const; 231 232 bool addressRangeContainsAddress(const uint64_t Address) const; 233 234 /// If a DIE represents a subprogram (or inlined subroutine), returns its 235 /// mangled name (or short name, if mangled is missing). This name may be 236 /// fetched from specification or abstract origin for this subprogram. 237 /// Returns null if no name is found. 238 const char *getSubroutineName(DINameKind Kind) const; 239 240 /// Return the DIE name resolving DW_AT_sepcification or DW_AT_abstract_origin 241 /// references if necessary. Returns null if no name is found. 242 const char *getName(DINameKind Kind) const; 243 244 /// Returns the declaration line (start line) for a DIE, assuming it specifies 245 /// a subprogram. This may be fetched from specification or abstract origin 246 /// for this subprogram by resolving DW_AT_sepcification or 247 /// DW_AT_abstract_origin references if necessary. 248 uint64_t getDeclLine() const; 249 250 /// Retrieves values of DW_AT_call_file, DW_AT_call_line and DW_AT_call_column 251 /// from DIE (or zeroes if they are missing). This function looks for 252 /// DW_AT_call attributes in this DIE only, it will not resolve the attribute 253 /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs. 254 /// \param CallFile filled in with non-zero if successful, zero if there is no 255 /// DW_AT_call_file attribute in this DIE. 256 /// \param CallLine filled in with non-zero if successful, zero if there is no 257 /// DW_AT_call_line attribute in this DIE. 258 /// \param CallColumn filled in with non-zero if successful, zero if there is 259 /// no DW_AT_call_column attribute in this DIE. 260 /// \param CallDiscriminator filled in with non-zero if successful, zero if 261 /// there is no DW_AT_GNU_discriminator attribute in this DIE. 262 void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine, 263 uint32_t &CallColumn, uint32_t &CallDiscriminator) const; 264 265 class attribute_iterator; 266 267 /// Get an iterator range to all attributes in the current DIE only. 268 /// 269 /// \returns an iterator range for the attributes of the current DIE. 270 iterator_range<attribute_iterator> attributes() const; 271 272 class iterator; 273 274 iterator begin() const; 275 iterator end() const; 276 277 std::reverse_iterator<iterator> rbegin() const; 278 std::reverse_iterator<iterator> rend() const; 279 280 iterator_range<iterator> children() const; 281}; 282 283class DWARFDie::attribute_iterator 284 : public iterator_facade_base<attribute_iterator, std::forward_iterator_tag, 285 const DWARFAttribute> { 286 /// The DWARF DIE we are extracting attributes from. 287 DWARFDie Die; 288 /// The value vended to clients via the operator*() or operator->(). 289 DWARFAttribute AttrValue; 290 /// The attribute index within the abbreviation declaration in Die. 291 uint32_t Index; 292 293 friend bool operator==(const attribute_iterator &LHS, 294 const attribute_iterator &RHS); 295 296 /// Update the attribute index and attempt to read the attribute value. If the 297 /// attribute is able to be read, update AttrValue and the Index member 298 /// variable. If the attribute value is not able to be read, an appropriate 299 /// error will be set if the Err member variable is non-NULL and the iterator 300 /// will be set to the end value so iteration stops. 301 void updateForIndex(const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I); 302 303public: 304 attribute_iterator() = delete; 305 explicit attribute_iterator(DWARFDie D, bool End); 306 307 attribute_iterator &operator++(); 308 attribute_iterator &operator--(); 309 explicit operator bool() const { return AttrValue.isValid(); } 310 const DWARFAttribute &operator*() const { return AttrValue; } 311}; 312 313inline bool operator==(const DWARFDie::attribute_iterator &LHS, 314 const DWARFDie::attribute_iterator &RHS) { 315 return LHS.Index == RHS.Index; 316} 317 318inline bool operator!=(const DWARFDie::attribute_iterator &LHS, 319 const DWARFDie::attribute_iterator &RHS) { 320 return !(LHS == RHS); 321} 322 323inline bool operator==(const DWARFDie &LHS, const DWARFDie &RHS) { 324 return LHS.getDebugInfoEntry() == RHS.getDebugInfoEntry() && 325 LHS.getDwarfUnit() == RHS.getDwarfUnit(); 326} 327 328inline bool operator!=(const DWARFDie &LHS, const DWARFDie &RHS) { 329 return !(LHS == RHS); 330} 331 332inline bool operator<(const DWARFDie &LHS, const DWARFDie &RHS) { 333 return LHS.getOffset() < RHS.getOffset(); 334} 335 336class DWARFDie::iterator 337 : public iterator_facade_base<iterator, std::bidirectional_iterator_tag, 338 const DWARFDie> { 339 DWARFDie Die; 340 341 friend std::reverse_iterator<llvm::DWARFDie::iterator>; 342 friend bool operator==(const DWARFDie::iterator &LHS, 343 const DWARFDie::iterator &RHS); 344 345public: 346 iterator() = default; 347 348 explicit iterator(DWARFDie D) : Die(D) {} 349 350 iterator &operator++() { 351 Die = Die.getSibling(); 352 return *this; 353 } 354 355 iterator &operator--() { 356 Die = Die.getPreviousSibling(); 357 return *this; 358 } 359 360 const DWARFDie &operator*() const { return Die; } 361}; 362 363inline bool operator==(const DWARFDie::iterator &LHS, 364 const DWARFDie::iterator &RHS) { 365 return LHS.Die == RHS.Die; 366} 367 368inline bool operator!=(const DWARFDie::iterator &LHS, 369 const DWARFDie::iterator &RHS) { 370 return !(LHS == RHS); 371} 372 373// These inline functions must follow the DWARFDie::iterator definition above 374// as they use functions from that class. 375inline DWARFDie::iterator DWARFDie::begin() const { 376 return iterator(getFirstChild()); 377} 378 379inline DWARFDie::iterator DWARFDie::end() const { 380 return iterator(getLastChild()); 381} 382 383inline iterator_range<DWARFDie::iterator> DWARFDie::children() const { 384 return make_range(begin(), end()); 385} 386 387} // end namespace llvm 388 389namespace std { 390 391template <> 392class reverse_iterator<llvm::DWARFDie::iterator> 393 : public llvm::iterator_facade_base< 394 reverse_iterator<llvm::DWARFDie::iterator>, 395 bidirectional_iterator_tag, const llvm::DWARFDie> { 396 397private: 398 llvm::DWARFDie Die; 399 bool AtEnd; 400 401public: 402 reverse_iterator(llvm::DWARFDie::iterator It) 403 : Die(It.Die), AtEnd(!It.Die.getPreviousSibling()) { 404 if (!AtEnd) 405 Die = Die.getPreviousSibling(); 406 } 407 408 llvm::DWARFDie::iterator base() const { 409 return llvm::DWARFDie::iterator(AtEnd ? Die : Die.getSibling()); 410 } 411 412 reverse_iterator<llvm::DWARFDie::iterator> &operator++() { 413 assert(!AtEnd && "Incrementing rend"); 414 llvm::DWARFDie D = Die.getPreviousSibling(); 415 if (D) 416 Die = D; 417 else 418 AtEnd = true; 419 return *this; 420 } 421 422 reverse_iterator<llvm::DWARFDie::iterator> &operator--() { 423 if (AtEnd) { 424 AtEnd = false; 425 return *this; 426 } 427 Die = Die.getSibling(); 428 assert(!Die.isNULL() && "Decrementing rbegin"); 429 return *this; 430 } 431 432 const llvm::DWARFDie &operator*() const { 433 assert(Die.isValid()); 434 return Die; 435 } 436 437 // FIXME: We should be able to specify the equals operator as a friend, but 438 // that causes the compiler to think the operator overload is ambiguous 439 // with the friend declaration and the actual definition as candidates. 440 bool equals(const reverse_iterator<llvm::DWARFDie::iterator> &RHS) const { 441 return Die == RHS.Die && AtEnd == RHS.AtEnd; 442 } 443}; 444 445} // namespace std 446 447namespace llvm { 448 449inline bool operator==(const std::reverse_iterator<DWARFDie::iterator> &LHS, 450 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 451 return LHS.equals(RHS); 452} 453 454inline bool operator!=(const std::reverse_iterator<DWARFDie::iterator> &LHS, 455 const std::reverse_iterator<DWARFDie::iterator> &RHS) { 456 return !(LHS == RHS); 457} 458 459inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rbegin() const { 460 return llvm::make_reverse_iterator(end()); 461} 462 463inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rend() const { 464 return llvm::make_reverse_iterator(begin()); 465} 466 467} // end namespace llvm 468 469#endif // LLVM_DEBUGINFO_DWARFDIE_H 470