1//===- DWARFFormValue.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_DWARFFORMVALUE_H
10#define LLVM_DEBUGINFO_DWARFFORMVALUE_H
11
12#include "llvm/ADT/ArrayRef.h"
13#include "llvm/ADT/None.h"
14#include "llvm/ADT/Optional.h"
15#include "llvm/BinaryFormat/Dwarf.h"
16#include "llvm/DebugInfo/DIContext.h"
17#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
18#include <cstdint>
19
20namespace llvm {
21
22class DWARFContext;
23class DWARFUnit;
24class raw_ostream;
25
26class DWARFFormValue {
27public:
28  enum FormClass {
29    FC_Unknown,
30    FC_Address,
31    FC_Block,
32    FC_Constant,
33    FC_String,
34    FC_Flag,
35    FC_Reference,
36    FC_Indirect,
37    FC_SectionOffset,
38    FC_Exprloc
39  };
40
41private:
42  struct ValueType {
43    ValueType() { uval = 0; }
44    ValueType(int64_t V) : sval(V) {}
45    ValueType(uint64_t V) : uval(V) {}
46    ValueType(const char *V) : cstr(V) {}
47
48    union {
49      uint64_t uval;
50      int64_t sval;
51      const char *cstr;
52    };
53    const uint8_t *data = nullptr;
54    uint64_t SectionIndex;      /// Section index for reference forms.
55  };
56
57  dwarf::Form Form;             /// Form for this value.
58  ValueType Value;              /// Contains all data for the form.
59  const DWARFUnit *U = nullptr; /// Remember the DWARFUnit at extract time.
60  const DWARFContext *C = nullptr; /// Context for extract time.
61
62  DWARFFormValue(dwarf::Form F, ValueType V) : Form(F), Value(V) {}
63
64public:
65  DWARFFormValue(dwarf::Form F = dwarf::Form(0)) : Form(F) {}
66
67  static DWARFFormValue createFromSValue(dwarf::Form F, int64_t V);
68  static DWARFFormValue createFromUValue(dwarf::Form F, uint64_t V);
69  static DWARFFormValue createFromPValue(dwarf::Form F, const char *V);
70  static DWARFFormValue createFromBlockValue(dwarf::Form F,
71                                             ArrayRef<uint8_t> D);
72  static DWARFFormValue createFromUnit(dwarf::Form F, const DWARFUnit *Unit,
73                                       uint64_t *OffsetPtr);
74
75  dwarf::Form getForm() const { return Form; }
76  uint64_t getRawUValue() const { return Value.uval; }
77
78  bool isFormClass(FormClass FC) const;
79  const DWARFUnit *getUnit() const { return U; }
80  void dump(raw_ostream &OS, DIDumpOptions DumpOpts = DIDumpOptions()) const;
81  void dumpSectionedAddress(raw_ostream &OS, DIDumpOptions DumpOpts,
82                            object::SectionedAddress SA) const;
83  static void dumpAddressSection(const DWARFObject &Obj, raw_ostream &OS,
84                                 DIDumpOptions DumpOpts, uint64_t SectionIndex);
85
86  /// Extracts a value in \p Data at offset \p *OffsetPtr. The information
87  /// in \p FormParams is needed to interpret some forms. The optional
88  /// \p Context and \p Unit allows extracting information if the form refers
89  /// to other sections (e.g., .debug_str).
90  bool extractValue(const DWARFDataExtractor &Data, uint64_t *OffsetPtr,
91                    dwarf::FormParams FormParams,
92                    const DWARFContext *Context = nullptr,
93                    const DWARFUnit *Unit = nullptr);
94
95  bool extractValue(const DWARFDataExtractor &Data, uint64_t *OffsetPtr,
96                    dwarf::FormParams FormParams, const DWARFUnit *U) {
97    return extractValue(Data, OffsetPtr, FormParams, nullptr, U);
98  }
99
100  bool isInlinedCStr() const {
101    return Value.data != nullptr && Value.data == (const uint8_t *)Value.cstr;
102  }
103
104  /// getAsFoo functions below return the extracted value as Foo if only
105  /// DWARFFormValue has form class is suitable for representing Foo.
106  Optional<uint64_t> getAsReference() const;
107  struct UnitOffset {
108    DWARFUnit *Unit;
109    uint64_t Offset;
110  };
111  Optional<UnitOffset> getAsRelativeReference() const;
112  Optional<uint64_t> getAsUnsignedConstant() const;
113  Optional<int64_t> getAsSignedConstant() const;
114  Optional<const char *> getAsCString() const;
115  Optional<uint64_t> getAsAddress() const;
116  Optional<object::SectionedAddress> getAsSectionedAddress() const;
117  Optional<uint64_t> getAsSectionOffset() const;
118  Optional<ArrayRef<uint8_t>> getAsBlock() const;
119  Optional<uint64_t> getAsCStringOffset() const;
120  Optional<uint64_t> getAsReferenceUVal() const;
121
122  /// Skip a form's value in \p DebugInfoData at the offset specified by
123  /// \p OffsetPtr.
124  ///
125  /// Skips the bytes for the current form and updates the offset.
126  ///
127  /// \param DebugInfoData The data where we want to skip the value.
128  /// \param OffsetPtr A reference to the offset that will be updated.
129  /// \param Params DWARF parameters to help interpret forms.
130  /// \returns true on success, false if the form was not skipped.
131  bool skipValue(DataExtractor DebugInfoData, uint64_t *OffsetPtr,
132                 const dwarf::FormParams Params) const {
133    return DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr, Params);
134  }
135
136  /// Skip a form's value in \p DebugInfoData at the offset specified by
137  /// \p OffsetPtr.
138  ///
139  /// Skips the bytes for the specified form and updates the offset.
140  ///
141  /// \param Form The DW_FORM enumeration that indicates the form to skip.
142  /// \param DebugInfoData The data where we want to skip the value.
143  /// \param OffsetPtr A reference to the offset that will be updated.
144  /// \param FormParams DWARF parameters to help interpret forms.
145  /// \returns true on success, false if the form was not skipped.
146  static bool skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
147                        uint64_t *OffsetPtr,
148                        const dwarf::FormParams FormParams);
149
150private:
151  void dumpString(raw_ostream &OS) const;
152};
153
154namespace dwarf {
155
156/// Take an optional DWARFFormValue and try to extract a string value from it.
157///
158/// \param V and optional DWARFFormValue to attempt to extract the value from.
159/// \returns an optional value that contains a value if the form value
160/// was valid and was a string.
161inline Optional<const char *> toString(const Optional<DWARFFormValue> &V) {
162  if (V)
163    return V->getAsCString();
164  return None;
165}
166
167/// Take an optional DWARFFormValue and try to extract a string value from it.
168///
169/// \param V and optional DWARFFormValue to attempt to extract the value from.
170/// \returns an optional value that contains a value if the form value
171/// was valid and was a string.
172inline StringRef toStringRef(const Optional<DWARFFormValue> &V,
173                             StringRef Default = {}) {
174  if (V)
175    if (auto S = V->getAsCString())
176      return *S;
177  return Default;
178}
179
180/// Take an optional DWARFFormValue and extract a string value from it.
181///
182/// \param V and optional DWARFFormValue to attempt to extract the value from.
183/// \param Default the default value to return in case of failure.
184/// \returns the string value or Default if the V doesn't have a value or the
185/// form value's encoding wasn't a string.
186inline const char *toString(const Optional<DWARFFormValue> &V,
187                            const char *Default) {
188  return toString(V).getValueOr(Default);
189}
190
191/// Take an optional DWARFFormValue and try to extract an unsigned constant.
192///
193/// \param V and optional DWARFFormValue to attempt to extract the value from.
194/// \returns an optional value that contains a value if the form value
195/// was valid and has a unsigned constant form.
196inline Optional<uint64_t> toUnsigned(const Optional<DWARFFormValue> &V) {
197  if (V)
198    return V->getAsUnsignedConstant();
199  return None;
200}
201
202/// Take an optional DWARFFormValue and extract a unsigned constant.
203///
204/// \param V and optional DWARFFormValue to attempt to extract the value from.
205/// \param Default the default value to return in case of failure.
206/// \returns the extracted unsigned value or Default if the V doesn't have a
207/// value or the form value's encoding wasn't an unsigned constant form.
208inline uint64_t toUnsigned(const Optional<DWARFFormValue> &V,
209                           uint64_t Default) {
210  return toUnsigned(V).getValueOr(Default);
211}
212
213/// Take an optional DWARFFormValue and try to extract an reference.
214///
215/// \param V and optional DWARFFormValue to attempt to extract the value from.
216/// \returns an optional value that contains a value if the form value
217/// was valid and has a reference form.
218inline Optional<uint64_t> toReference(const Optional<DWARFFormValue> &V) {
219  if (V)
220    return V->getAsReference();
221  return None;
222}
223
224/// Take an optional DWARFFormValue and extract a reference.
225///
226/// \param V and optional DWARFFormValue to attempt to extract the value from.
227/// \param Default the default value to return in case of failure.
228/// \returns the extracted reference value or Default if the V doesn't have a
229/// value or the form value's encoding wasn't a reference form.
230inline uint64_t toReference(const Optional<DWARFFormValue> &V,
231                            uint64_t Default) {
232  return toReference(V).getValueOr(Default);
233}
234
235/// Take an optional DWARFFormValue and try to extract an signed constant.
236///
237/// \param V and optional DWARFFormValue to attempt to extract the value from.
238/// \returns an optional value that contains a value if the form value
239/// was valid and has a signed constant form.
240inline Optional<int64_t> toSigned(const Optional<DWARFFormValue> &V) {
241  if (V)
242    return V->getAsSignedConstant();
243  return None;
244}
245
246/// Take an optional DWARFFormValue and extract a signed integer.
247///
248/// \param V and optional DWARFFormValue to attempt to extract the value from.
249/// \param Default the default value to return in case of failure.
250/// \returns the extracted signed integer value or Default if the V doesn't
251/// have a value or the form value's encoding wasn't a signed integer form.
252inline int64_t toSigned(const Optional<DWARFFormValue> &V, int64_t Default) {
253  return toSigned(V).getValueOr(Default);
254}
255
256/// Take an optional DWARFFormValue and try to extract an address.
257///
258/// \param V and optional DWARFFormValue to attempt to extract the value from.
259/// \returns an optional value that contains a value if the form value
260/// was valid and has a address form.
261inline Optional<uint64_t> toAddress(const Optional<DWARFFormValue> &V) {
262  if (V)
263    return V->getAsAddress();
264  return None;
265}
266
267inline Optional<object::SectionedAddress>
268toSectionedAddress(const Optional<DWARFFormValue> &V) {
269  if (V)
270    return V->getAsSectionedAddress();
271  return None;
272}
273
274/// Take an optional DWARFFormValue and extract a address.
275///
276/// \param V and optional DWARFFormValue to attempt to extract the value from.
277/// \param Default the default value to return in case of failure.
278/// \returns the extracted address value or Default if the V doesn't have a
279/// value or the form value's encoding wasn't an address form.
280inline uint64_t toAddress(const Optional<DWARFFormValue> &V, uint64_t Default) {
281  return toAddress(V).getValueOr(Default);
282}
283
284/// Take an optional DWARFFormValue and try to extract an section offset.
285///
286/// \param V and optional DWARFFormValue to attempt to extract the value from.
287/// \returns an optional value that contains a value if the form value
288/// was valid and has a section offset form.
289inline Optional<uint64_t> toSectionOffset(const Optional<DWARFFormValue> &V) {
290  if (V)
291    return V->getAsSectionOffset();
292  return None;
293}
294
295/// Take an optional DWARFFormValue and extract a section offset.
296///
297/// \param V and optional DWARFFormValue to attempt to extract the value from.
298/// \param Default the default value to return in case of failure.
299/// \returns the extracted section offset value or Default if the V doesn't
300/// have a value or the form value's encoding wasn't a section offset form.
301inline uint64_t toSectionOffset(const Optional<DWARFFormValue> &V,
302                                uint64_t Default) {
303  return toSectionOffset(V).getValueOr(Default);
304}
305
306/// Take an optional DWARFFormValue and try to extract block data.
307///
308/// \param V and optional DWARFFormValue to attempt to extract the value from.
309/// \returns an optional value that contains a value if the form value
310/// was valid and has a block form.
311inline Optional<ArrayRef<uint8_t>> toBlock(const Optional<DWARFFormValue> &V) {
312  if (V)
313    return V->getAsBlock();
314  return None;
315}
316
317} // end namespace dwarf
318
319} // end namespace llvm
320
321#endif // LLVM_DEBUGINFO_DWARFFORMVALUE_H
322