• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 //===- DWARFVerifier.h ----------------------------------------------------===//
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_DWARF_DWARFVERIFIER_H
11 #define LLVM_DEBUGINFO_DWARF_DWARFVERIFIER_H
12 
13 #include "llvm/DebugInfo/DIContext.h"
14 #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
15 #include "llvm/DebugInfo/DWARF/DWARFAddressRange.h"
16 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
17 
18 #include <cstdint>
19 #include <map>
20 #include <set>
21 
22 namespace llvm {
23 class raw_ostream;
24 struct DWARFAttribute;
25 class DWARFContext;
26 class DWARFDie;
27 class DWARFUnit;
28 class DWARFCompileUnit;
29 class DWARFDataExtractor;
30 class DWARFDebugAbbrev;
31 class DataExtractor;
32 struct DWARFSection;
33 
34 /// A class that verifies DWARF debug information given a DWARF Context.
35 class DWARFVerifier {
36 public:
37   /// A class that keeps the address range information for a single DIE.
38   struct DieRangeInfo {
39     DWARFDie Die;
40 
41     /// Sorted DWARFAddressRanges.
42     std::vector<DWARFAddressRange> Ranges;
43 
44     /// Sorted DWARFAddressRangeInfo.
45     std::set<DieRangeInfo> Children;
46 
47     DieRangeInfo() = default;
DieRangeInfoDieRangeInfo48     DieRangeInfo(DWARFDie Die) : Die(Die) {}
49 
50     /// Used for unit testing.
DieRangeInfoDieRangeInfo51     DieRangeInfo(std::vector<DWARFAddressRange> Ranges)
52         : Ranges(std::move(Ranges)) {}
53 
54     typedef std::vector<DWARFAddressRange>::const_iterator
55         address_range_iterator;
56     typedef std::set<DieRangeInfo>::const_iterator die_range_info_iterator;
57 
58     /// Inserts the address range. If the range overlaps with an existing
59     /// range, the range is *not* added and an iterator to the overlapping
60     /// range is returned.
61     ///
62     /// This is used for finding overlapping ranges within the same DIE.
63     address_range_iterator insert(const DWARFAddressRange &R);
64 
65     /// Finds an address range in the sorted vector of ranges.
findRangeDieRangeInfo66     address_range_iterator findRange(const DWARFAddressRange &R) const {
67       auto Begin = Ranges.begin();
68       auto End = Ranges.end();
69       auto Iter = std::upper_bound(Begin, End, R);
70       if (Iter != Begin)
71         --Iter;
72       return Iter;
73     }
74 
75     /// Inserts the address range info. If any of its ranges overlaps with a
76     /// range in an existing range info, the range info is *not* added and an
77     /// iterator to the overlapping range info.
78     ///
79     /// This is used for finding overlapping children of the same DIE.
80     die_range_info_iterator insert(const DieRangeInfo &RI);
81 
82     /// Return true if ranges in this object contains all ranges within RHS.
83     bool contains(const DieRangeInfo &RHS) const;
84 
85     /// Return true if any range in this object intersects with any range in
86     /// RHS.
87     bool intersects(const DieRangeInfo &RHS) const;
88   };
89 
90 private:
91   raw_ostream &OS;
92   DWARFContext &DCtx;
93   DIDumpOptions DumpOpts;
94   /// A map that tracks all references (converted absolute references) so we
95   /// can verify each reference points to a valid DIE and not an offset that
96   /// lies between to valid DIEs.
97   std::map<uint64_t, std::set<uint32_t>> ReferenceToDIEOffsets;
98   uint32_t NumDebugLineErrors = 0;
99 
100   raw_ostream &error() const;
101   raw_ostream &warn() const;
102   raw_ostream &note() const;
103 
104   /// Verifies the abbreviations section.
105   ///
106   /// This function currently checks that:
107   /// --No abbreviation declaration has more than one attributes with the same
108   /// name.
109   ///
110   /// \param Abbrev Pointer to the abbreviations section we are verifying
111   /// Abbrev can be a pointer to either .debug_abbrev or debug_abbrev.dwo.
112   ///
113   /// \returns The number of errors that occurred during verification.
114   unsigned verifyAbbrevSection(const DWARFDebugAbbrev *Abbrev);
115 
116   /// Verifies the header of a unit in the .debug_info section.
117   ///
118   /// This function currently checks for:
119   /// - Unit is in 32-bit DWARF format. The function can be modified to
120   /// support 64-bit format.
121   /// - The DWARF version is valid
122   /// - The unit type is valid (if unit is in version >=5)
123   /// - The unit doesn't extend beyond .debug_info section
124   /// - The address size is valid
125   /// - The offset in the .debug_abbrev section is valid
126   ///
127   /// \param DebugInfoData The .debug_info section data
128   /// \param Offset A reference to the offset start of the unit. The offset will
129   /// be updated to point to the next unit in .debug_info
130   /// \param UnitIndex The index of the unit to be verified
131   /// \param UnitType A reference to the type of the unit
132   /// \param isUnitDWARF64 A reference to a flag that shows whether the unit is
133   /// in 64-bit format.
134   ///
135   /// \returns true if the header is verified successfully, false otherwise.
136   bool verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
137                         uint32_t *Offset, unsigned UnitIndex, uint8_t &UnitType,
138                         bool &isUnitDWARF64);
139 
140   /// Verifies the header of a unit in the .debug_info section.
141   ///
142   /// This function currently verifies:
143   ///  - The debug info attributes.
144   ///  - The debug info form=s.
145   ///  - The presence of a root DIE.
146   ///  - That the root DIE is a unit DIE.
147   ///  - If a unit type is provided, that the unit DIE matches the unit type.
148   ///  - The DIE ranges.
149   ///
150   /// \param Unit      The DWARF Unit to verifiy.
151   /// \param UnitType  An optional unit type which will be used to verify the
152   ///                  type of the unit DIE.
153   ///
154   /// \returns true if the content is verified successfully, false otherwise.
155   bool verifyUnitContents(DWARFUnit &Unit, uint8_t UnitType = 0);
156 
157   /// Verify that all Die ranges are valid.
158   ///
159   /// This function currently checks for:
160   /// - cases in which lowPC >= highPC
161   ///
162   /// \returns Number of errors that occurred during verification.
163   unsigned verifyDieRanges(const DWARFDie &Die, DieRangeInfo &ParentRI);
164 
165   /// Verifies the attribute's DWARF attribute and its value.
166   ///
167   /// This function currently checks for:
168   /// - DW_AT_ranges values is a valid .debug_ranges offset
169   /// - DW_AT_stmt_list is a valid .debug_line offset
170   ///
171   /// \param Die          The DWARF DIE that owns the attribute value
172   /// \param AttrValue    The DWARF attribute value to check
173   ///
174   /// \returns NumErrors The number of errors occurred during verification of
175   /// attributes' values in a .debug_info section unit
176   unsigned verifyDebugInfoAttribute(const DWARFDie &Die,
177                                     DWARFAttribute &AttrValue);
178 
179   /// Verifies the attribute's DWARF form.
180   ///
181   /// This function currently checks for:
182   /// - All DW_FORM_ref values that are CU relative have valid CU offsets
183   /// - All DW_FORM_ref_addr values have valid .debug_info offsets
184   /// - All DW_FORM_strp values have valid .debug_str offsets
185   ///
186   /// \param Die          The DWARF DIE that owns the attribute value
187   /// \param AttrValue    The DWARF attribute value to check
188   ///
189   /// \returns NumErrors The number of errors occurred during verification of
190   /// attributes' forms in a .debug_info section unit
191   unsigned verifyDebugInfoForm(const DWARFDie &Die, DWARFAttribute &AttrValue);
192 
193   /// Verifies the all valid references that were found when iterating through
194   /// all of the DIE attributes.
195   ///
196   /// This function will verify that all references point to DIEs whose DIE
197   /// offset matches. This helps to ensure if a DWARF link phase moved things
198   /// around, that it doesn't create invalid references by failing to relocate
199   /// CU relative and absolute references.
200   ///
201   /// \returns NumErrors The number of errors occurred during verification of
202   /// references for the .debug_info section
203   unsigned verifyDebugInfoReferences();
204 
205   /// Verify the DW_AT_stmt_list encoding and value and ensure that no
206   /// compile units that have the same DW_AT_stmt_list value.
207   void verifyDebugLineStmtOffsets();
208 
209   /// Verify that all of the rows in the line table are valid.
210   ///
211   /// This function currently checks for:
212   /// - addresses within a sequence that decrease in value
213   /// - invalid file indexes
214   void verifyDebugLineRows();
215 
216   /// Verify that an Apple-style accelerator table is valid.
217   ///
218   /// This function currently checks that:
219   /// - The fixed part of the header fits in the section
220   /// - The size of the section is as large as what the header describes
221   /// - There is at least one atom
222   /// - The form for each atom is valid
223   /// - The tag for each DIE in the table is valid
224   /// - The buckets have a valid index, or they are empty
225   /// - Each hashdata offset is valid
226   /// - Each DIE is valid
227   ///
228   /// \param AccelSection pointer to the section containing the acceleration table
229   /// \param StrData pointer to the string section
230   /// \param SectionName the name of the table we're verifying
231   ///
232   /// \returns The number of errors occurred during verification
233   unsigned verifyAppleAccelTable(const DWARFSection *AccelSection,
234                                  DataExtractor *StrData,
235                                  const char *SectionName);
236 
237   unsigned verifyDebugNamesCULists(const DWARFDebugNames &AccelTable);
238   unsigned verifyNameIndexBuckets(const DWARFDebugNames::NameIndex &NI,
239                                   const DataExtractor &StrData);
240   unsigned verifyNameIndexAbbrevs(const DWARFDebugNames::NameIndex &NI);
241   unsigned verifyNameIndexAttribute(const DWARFDebugNames::NameIndex &NI,
242                                     const DWARFDebugNames::Abbrev &Abbr,
243                                     DWARFDebugNames::AttributeEncoding AttrEnc);
244   unsigned verifyNameIndexEntries(const DWARFDebugNames::NameIndex &NI,
245                                   const DWARFDebugNames::NameTableEntry &NTE);
246   unsigned verifyNameIndexCompleteness(const DWARFDie &Die,
247                                        const DWARFDebugNames::NameIndex &NI);
248 
249   /// Verify that the DWARF v5 accelerator table is valid.
250   ///
251   /// This function currently checks that:
252   /// - Headers individual Name Indices fit into the section and can be parsed.
253   /// - Abbreviation tables can be parsed and contain valid index attributes
254   ///   with correct form encodings.
255   /// - The CU lists reference existing compile units.
256   /// - The buckets have a valid index, or they are empty.
257   /// - All names are reachable via the hash table (they have the correct hash,
258   ///   and the hash is in the correct bucket).
259   /// - Information in the index entries is complete (all required entries are
260   ///   present) and consistent with the debug_info section DIEs.
261   ///
262   /// \param AccelSection section containing the acceleration table
263   /// \param StrData string section
264   ///
265   /// \returns The number of errors occurred during verification
266   unsigned verifyDebugNames(const DWARFSection &AccelSection,
267                             const DataExtractor &StrData);
268 
269 public:
270   DWARFVerifier(raw_ostream &S, DWARFContext &D,
271                 DIDumpOptions DumpOpts = DIDumpOptions::getForSingleDIE())
OS(S)272       : OS(S), DCtx(D), DumpOpts(std::move(DumpOpts)) {}
273   /// Verify the information in any of the following sections, if available:
274   /// .debug_abbrev, debug_abbrev.dwo
275   ///
276   /// Any errors are reported to the stream that was this object was
277   /// constructed with.
278   ///
279   /// \returns true if .debug_abbrev and .debug_abbrev.dwo verify successfully,
280   /// false otherwise.
281   bool handleDebugAbbrev();
282 
283   /// Verify the information in the .debug_info section.
284   ///
285   /// Any errors are reported to the stream that was this object was
286   /// constructed with.
287   ///
288   /// \returns true if the .debug_info verifies successfully, false otherwise.
289   bool handleDebugInfo();
290 
291   /// Verify the information in the .debug_line section.
292   ///
293   /// Any errors are reported to the stream that was this object was
294   /// constructed with.
295   ///
296   /// \returns true if the .debug_line verifies successfully, false otherwise.
297   bool handleDebugLine();
298 
299   /// Verify the information in accelerator tables, if they exist.
300   ///
301   /// Any errors are reported to the stream that was this object was
302   /// constructed with.
303   ///
304   /// \returns true if the existing Apple-style accelerator tables verify
305   /// successfully, false otherwise.
306   bool handleAccelTables();
307 };
308 
309 static inline bool operator<(const DWARFVerifier::DieRangeInfo &LHS,
310                              const DWARFVerifier::DieRangeInfo &RHS) {
311   return std::tie(LHS.Ranges, LHS.Die) < std::tie(RHS.Ranges, RHS.Die);
312 }
313 
314 } // end namespace llvm
315 
316 #endif // LLVM_DEBUGINFO_DWARF_DWARFCONTEXT_H
317