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_DWARF_DWARFDIE_H
10#define LLVM_DEBUGINFO_DWARF_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
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 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
300class 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
320public:
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
330inline bool operator==(const DWARFDie::attribute_iterator &LHS,
331 const DWARFDie::attribute_iterator &RHS) {
332 return LHS.Index == RHS.Index;
333}
334
335inline bool operator!=(const DWARFDie::attribute_iterator &LHS,
336 const DWARFDie::attribute_iterator &RHS) {
337 return !(LHS == RHS);
338}
339
340inline bool operator==(const DWARFDie &LHS, const DWARFDie &RHS) {
341 return LHS.getDebugInfoEntry() == RHS.getDebugInfoEntry() &&
342 LHS.getDwarfUnit() == RHS.getDwarfUnit();
343}
344
345inline bool operator!=(const DWARFDie &LHS, const DWARFDie &RHS) {
346 return !(LHS == RHS);
347}
348
349inline bool operator<(const DWARFDie &LHS, const DWARFDie &RHS) {
350 return LHS.getOffset() < RHS.getOffset();
351}
352
353class 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
362public:
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
380inline 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.
387inline DWARFDie::iterator DWARFDie::begin() const {
388 return iterator(getFirstChild());
389}
390
391inline DWARFDie::iterator DWARFDie::end() const {
392 return iterator(getLastChild());
393}
394
395inline iterator_range<DWARFDie::iterator> DWARFDie::children() const {
396 return make_range(begin(), end());
397}
398
399} // end namespace llvm
400
401namespace std {
402
403template <>
404class 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
409private:
410 llvm::DWARFDie Die;
411 bool AtEnd;
412
413public:
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
459namespace llvm {
460
461inline bool operator==(const std::reverse_iterator<DWARFDie::iterator> &LHS,
462 const std::reverse_iterator<DWARFDie::iterator> &RHS) {
463 return LHS.equals(RHS);
464}
465
466inline bool operator!=(const std::reverse_iterator<DWARFDie::iterator> &LHS,
467 const std::reverse_iterator<DWARFDie::iterator> &RHS) {
468 return !(LHS == RHS);
469}
470
471inline std::reverse_iterator<DWARFDie::iterator> DWARFDie::rbegin() const {
472 return llvm::make_reverse_iterator(end());
473}
474
475inline 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_DWARF_DWARFDIE_H
482