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/DWARFAttribute.h" 20#include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h" 21#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.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 { 86 return getAbbreviationDeclarationPtr() == nullptr; 87 } 88 89 /// Returns true if DIE represents a subprogram (not inlined). 90 bool isSubprogramDIE() const; 91 92 /// Returns true if DIE represents a subprogram or an inlined subroutine. 93 bool isSubroutineDIE() const; 94 95 /// Get the parent of this DIE object. 96 /// 97 /// \returns a valid DWARFDie instance if this object has a parent or an 98 /// invalid DWARFDie instance if it doesn't. 99 DWARFDie getParent() const; 100 101 /// Get the sibling of this DIE object. 102 /// 103 /// \returns a valid DWARFDie instance if this object has a sibling or an 104 /// invalid DWARFDie instance if it doesn't. 105 DWARFDie getSibling() const; 106 107 /// Get the first child of this DIE object. 108 /// 109 /// \returns a valid DWARFDie instance if this object has children or an 110 /// invalid DWARFDie instance if it doesn't. 111 DWARFDie getFirstChild() const { 112 if (isValid() && Die->hasChildren()) 113 return DWARFDie(U, Die + 1); 114 return DWARFDie(); 115 } 116 117 /// Dump the DIE and all of its attributes to the supplied stream. 118 /// 119 /// \param OS the stream to use for output. 120 /// \param indent the number of characters to indent each line that is output. 121 void dump(raw_ostream &OS, unsigned indent = 0, 122 DIDumpOptions DumpOpts = DIDumpOptions()) const; 123 124 125 /// Convenience zero-argument overload for debugging. 126 LLVM_DUMP_METHOD void dump() const; 127 128 /// Extract the specified attribute from this DIE. 129 /// 130 /// Extract an attribute value from this DIE only. This call doesn't look 131 /// for the attribute value in any DW_AT_specification or 132 /// DW_AT_abstract_origin referenced DIEs. 133 /// 134 /// \param Attr the attribute to extract. 135 /// \returns an optional DWARFFormValue that will have the form value if the 136 /// attribute was successfully extracted. 137 Optional<DWARFFormValue> find(dwarf::Attribute Attr) const; 138 139 /// Extract the first value of any attribute in Attrs from this DIE. 140 /// 141 /// Extract the first attribute that matches from this DIE only. This call 142 /// doesn't look for the attribute value in any DW_AT_specification or 143 /// DW_AT_abstract_origin referenced DIEs. The attributes will be searched 144 /// linearly in the order they are specified within Attrs. 145 /// 146 /// \param Attrs an array of DWARF attribute to look for. 147 /// \returns an optional that has a valid DWARFFormValue for the first 148 /// matching attribute in Attrs, or None if none of the attributes in Attrs 149 /// exist in this DIE. 150 Optional<DWARFFormValue> find(ArrayRef<dwarf::Attribute> Attrs) const; 151 152 /// Extract the first value of any attribute in Attrs from this DIE and 153 /// recurse into any DW_AT_specification or DW_AT_abstract_origin referenced 154 /// DIEs. 155 /// 156 /// \param Attrs an array of DWARF attribute to look for. 157 /// \returns an optional that has a valid DWARFFormValue for the first 158 /// matching attribute in Attrs, or None if none of the attributes in Attrs 159 /// exist in this DIE or in any DW_AT_specification or DW_AT_abstract_origin 160 /// DIEs. 161 Optional<DWARFFormValue> 162 findRecursively(ArrayRef<dwarf::Attribute> Attrs) const; 163 164 /// Extract the specified attribute from this DIE as the referenced DIE. 165 /// 166 /// Regardless of the reference type, return the correct DWARFDie instance if 167 /// the attribute exists. The returned DWARFDie object might be from another 168 /// DWARFUnit, but that is all encapsulated in the new DWARFDie object. 169 /// 170 /// Extract an attribute value from this DIE only. This call doesn't look 171 /// for the attribute value in any DW_AT_specification or 172 /// DW_AT_abstract_origin referenced DIEs. 173 /// 174 /// \param Attr the attribute to extract. 175 /// \returns a valid DWARFDie instance if the attribute exists, or an invalid 176 /// DWARFDie object if it doesn't. 177 DWARFDie getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const; 178 179 /// Extract the range base attribute from this DIE as absolute section offset. 180 /// 181 /// This is a utility function that checks for either the DW_AT_rnglists_base 182 /// or DW_AT_GNU_ranges_base attribute. 183 /// 184 /// \returns anm optional absolute section offset value for the attribute. 185 Optional<uint64_t> getRangesBaseAttribute() const; 186 187 /// Get the DW_AT_high_pc attribute value as an address. 188 /// 189 /// In DWARF version 4 and later the high PC can be encoded as an offset from 190 /// the DW_AT_low_pc. This function takes care of extracting the value as an 191 /// address or offset and adds it to the low PC if needed and returns the 192 /// value as an optional in case the DIE doesn't have a DW_AT_high_pc 193 /// attribute. 194 /// 195 /// \param LowPC the low PC that might be needed to calculate the high PC. 196 /// \returns an optional address value for the attribute. 197 Optional<uint64_t> getHighPC(uint64_t LowPC) const; 198 199 /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU. 200 /// Returns true if both attributes are present. 201 bool getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC, 202 uint64_t &SectionIndex) const; 203 204 /// Get the address ranges for this DIE. 205 /// 206 /// Get the hi/low PC range if both attributes are available or exrtracts the 207 /// non-contiguous address ranges from the DW_AT_ranges attribute. 208 /// 209 /// Extracts the range information from this DIE only. This call doesn't look 210 /// for the range in any DW_AT_specification or DW_AT_abstract_origin DIEs. 211 /// 212 /// \returns a address range vector that might be empty if no address range 213 /// information is available. 214 DWARFAddressRangesVector getAddressRanges() const; 215 216 /// Get all address ranges for any DW_TAG_subprogram DIEs in this DIE or any 217 /// of its children. 218 /// 219 /// Get the hi/low PC range if both attributes are available or exrtracts the 220 /// non-contiguous address ranges from the DW_AT_ranges attribute for this DIE 221 /// and all children. 222 /// 223 /// \param Ranges the addres range vector to fill in. 224 void collectChildrenAddressRanges(DWARFAddressRangesVector &Ranges) const; 225 226 bool addressRangeContainsAddress(const uint64_t Address) const; 227 228 /// If a DIE represents a subprogram (or inlined subroutine), returns its 229 /// mangled name (or short name, if mangled is missing). This name may be 230 /// fetched from specification or abstract origin for this subprogram. 231 /// Returns null if no name is found. 232 const char *getSubroutineName(DINameKind Kind) const; 233 234 /// Return the DIE name resolving DW_AT_sepcification or DW_AT_abstract_origin 235 /// references if necessary. Returns null if no name is found. 236 const char *getName(DINameKind Kind) const; 237 238 /// Returns the declaration line (start line) for a DIE, assuming it specifies 239 /// a subprogram. This may be fetched from specification or abstract origin 240 /// for this subprogram by resolving DW_AT_sepcification or 241 /// DW_AT_abstract_origin references if necessary. 242 uint64_t getDeclLine() const; 243 244 /// Retrieves values of DW_AT_call_file, DW_AT_call_line and DW_AT_call_column 245 /// from DIE (or zeroes if they are missing). This function looks for 246 /// DW_AT_call attributes in this DIE only, it will not resolve the attribute 247 /// values in any DW_AT_specification or DW_AT_abstract_origin DIEs. 248 /// \param CallFile filled in with non-zero if successful, zero if there is no 249 /// DW_AT_call_file attribute in this DIE. 250 /// \param CallLine filled in with non-zero if successful, zero if there is no 251 /// DW_AT_call_line attribute in this DIE. 252 /// \param CallColumn filled in with non-zero if successful, zero if there is 253 /// no DW_AT_call_column attribute in this DIE. 254 /// \param CallDiscriminator filled in with non-zero if successful, zero if 255 /// there is no DW_AT_GNU_discriminator attribute in this DIE. 256 void getCallerFrame(uint32_t &CallFile, uint32_t &CallLine, 257 uint32_t &CallColumn, uint32_t &CallDiscriminator) const; 258 259 class attribute_iterator; 260 261 /// Get an iterator range to all attributes in the current DIE only. 262 /// 263 /// \returns an iterator range for the attributes of the current DIE. 264 iterator_range<attribute_iterator> attributes() const; 265 266 class iterator; 267 268 iterator begin() const; 269 iterator end() const; 270 iterator_range<iterator> children() const; 271}; 272 273class DWARFDie::attribute_iterator : 274 public iterator_facade_base<attribute_iterator, std::forward_iterator_tag, 275 const DWARFAttribute> { 276 /// The DWARF DIE we are extracting attributes from. 277 DWARFDie Die; 278 /// The value vended to clients via the operator*() or operator->(). 279 DWARFAttribute AttrValue; 280 /// The attribute index within the abbreviation declaration in Die. 281 uint32_t Index; 282 283 /// Update the attribute index and attempt to read the attribute value. If the 284 /// attribute is able to be read, update AttrValue and the Index member 285 /// variable. If the attribute value is not able to be read, an appropriate 286 /// error will be set if the Err member variable is non-NULL and the iterator 287 /// will be set to the end value so iteration stops. 288 void updateForIndex(const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I); 289 290public: 291 attribute_iterator() = delete; 292 explicit attribute_iterator(DWARFDie D, bool End); 293 294 attribute_iterator &operator++(); 295 explicit operator bool() const { return AttrValue.isValid(); } 296 const DWARFAttribute &operator*() const { return AttrValue; } 297 bool operator==(const attribute_iterator &X) const { return Index == X.Index; } 298}; 299 300inline bool operator==(const DWARFDie &LHS, const DWARFDie &RHS) { 301 return LHS.getDebugInfoEntry() == RHS.getDebugInfoEntry() && 302 LHS.getDwarfUnit() == RHS.getDwarfUnit(); 303} 304 305inline bool operator!=(const DWARFDie &LHS, const DWARFDie &RHS) { 306 return !(LHS == RHS); 307} 308 309inline bool operator<(const DWARFDie &LHS, const DWARFDie &RHS) { 310 return LHS.getOffset() < RHS.getOffset(); 311} 312 313class DWARFDie::iterator : public iterator_facade_base<iterator, 314 std::forward_iterator_tag, 315 const DWARFDie> { 316 DWARFDie Die; 317 void skipNull() { 318 if (Die && Die.isNULL()) 319 Die = DWARFDie(); 320 } 321public: 322 iterator() = default; 323 324 explicit iterator(DWARFDie D) : Die(D) { 325 // If we start out with only a Null DIE then invalidate. 326 skipNull(); 327 } 328 329 iterator &operator++() { 330 Die = Die.getSibling(); 331 // Don't include the NULL die when iterating. 332 skipNull(); 333 return *this; 334 } 335 336 explicit operator bool() const { return Die.isValid(); } 337 const DWARFDie &operator*() const { return Die; } 338 bool operator==(const iterator &X) const { return Die == X.Die; } 339}; 340 341// These inline functions must follow the DWARFDie::iterator definition above 342// as they use functions from that class. 343inline DWARFDie::iterator DWARFDie::begin() const { 344 return iterator(getFirstChild()); 345} 346 347inline DWARFDie::iterator DWARFDie::end() const { 348 return iterator(); 349} 350 351inline iterator_range<DWARFDie::iterator> DWARFDie::children() const { 352 return make_range(begin(), end()); 353} 354 355} // end namespace llvm 356 357#endif // LLVM_DEBUGINFO_DWARFDIE_H 358