include/llvm/DebugInfo/DWARF/DWARFFormValue.h

   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
  20 namespace llvm {
  21
  22 class DWARFContext;
  23 class DWARFUnit;
  24 class raw_ostream;
  25
  26 class DWARFFormValue {
  27 public:
  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
  41 private:
  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
  64 public:
  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
 150 private:
 151   void dumpString(raw_ostream &OS) const;
 152 };
 153
 154 namespace 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.
 161 inline 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.
 172 inline 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.
 186 inline 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.
 196 inline 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.
 208 inline 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.
 218 inline 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.
 230 inline 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.
 240 inline 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.
 252 inline 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.
 261 inline Optional<uint64_t> toAddress(const Optional<DWARFFormValue> &V) {
 262   if (V)
 263     return V->getAsAddress();
 264   return None;
 265 }
 266
 267 inline Optional<object::SectionedAddress>
 268 toSectionedAddress(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.
 280 inline 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.
 289 inline 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.
 301 inline 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.
 311 inline 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