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
  45     union {
  46       uint64_t uval;
  47       int64_t sval;
  48       const char *cstr;
  49     };
  50     const uint8_t *data = nullptr;
  51     uint64_t SectionIndex;      /// Section index for reference forms.
  52   };
  53
  54   dwarf::Form Form;             /// Form for this value.
  55   ValueType Value;              /// Contains all data for the form.
  56   const DWARFUnit *U = nullptr; /// Remember the DWARFUnit at extract time.
  57   const DWARFContext *C = nullptr; /// Context for extract time.
  58 public:
  59   DWARFFormValue(dwarf::Form F = dwarf::Form(0)) : Form(F) {}
  60
  61   dwarf::Form getForm() const { return Form; }
  62   uint64_t getRawUValue() const { return Value.uval; }
  63   void setForm(dwarf::Form F) { Form = F; }
  64   void setUValue(uint64_t V) { Value.uval = V; }
  65   void setSValue(int64_t V) { Value.sval = V; }
  66   void setPValue(const char *V) { Value.cstr = V; }
  67
  68   void setBlockValue(const ArrayRef<uint8_t> &Data) {
  69     Value.data = Data.data();
  70     setUValue(Data.size());
  71   }
  72
  73   bool isFormClass(FormClass FC) const;
  74   const DWARFUnit *getUnit() const { return U; }
  75   void dump(raw_ostream &OS, DIDumpOptions DumpOpts = DIDumpOptions()) const;
  76   void dumpSectionedAddress(raw_ostream &OS, DIDumpOptions DumpOpts,
  77                             SectionedAddress SA) const;
  78   static void dumpAddressSection(const DWARFObject &Obj, raw_ostream &OS,
  79                                  DIDumpOptions DumpOpts, uint64_t SectionIndex);
  80
  81   /// Extracts a value in \p Data at offset \p *OffsetPtr. The information
  82   /// in \p FormParams is needed to interpret some forms. The optional
  83   /// \p Context and \p Unit allows extracting information if the form refers
  84   /// to other sections (e.g., .debug_str).
  85   bool extractValue(const DWARFDataExtractor &Data, uint32_t *OffsetPtr,
  86                     dwarf::FormParams FormParams,
  87                     const DWARFContext *Context = nullptr,
  88                     const DWARFUnit *Unit = nullptr);
  89
  90   bool extractValue(const DWARFDataExtractor &Data, uint32_t *OffsetPtr,
  91                     dwarf::FormParams FormParams, const DWARFUnit *U) {
  92     return extractValue(Data, OffsetPtr, FormParams, nullptr, U);
  93   }
  94
  95   bool isInlinedCStr() const {
  96     return Value.data != nullptr && Value.data == (const uint8_t *)Value.cstr;
  97   }
  98
  99   /// getAsFoo functions below return the extracted value as Foo if only
 100   /// DWARFFormValue has form class is suitable for representing Foo.
 101   Optional<uint64_t> getAsReference() const;
 102   Optional<uint64_t> getAsUnsignedConstant() const;
 103   Optional<int64_t> getAsSignedConstant() const;
 104   Optional<const char *> getAsCString() const;
 105   Optional<uint64_t> getAsAddress() const;
 106   Optional<SectionedAddress> getAsSectionedAddress() const;
 107   Optional<uint64_t> getAsSectionOffset() const;
 108   Optional<ArrayRef<uint8_t>> getAsBlock() const;
 109   Optional<uint64_t> getAsCStringOffset() const;
 110   Optional<uint64_t> getAsReferenceUVal() const;
 111
 112   /// Skip a form's value in \p DebugInfoData at the offset specified by
 113   /// \p OffsetPtr.
 114   ///
 115   /// Skips the bytes for the current form and updates the offset.
 116   ///
 117   /// \param DebugInfoData The data where we want to skip the value.
 118   /// \param OffsetPtr A reference to the offset that will be updated.
 119   /// \param Params DWARF parameters to help interpret forms.
 120   /// \returns true on success, false if the form was not skipped.
 121   bool skipValue(DataExtractor DebugInfoData, uint32_t *OffsetPtr,
 122                  const dwarf::FormParams Params) const {
 123     return DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr, Params);
 124   }
 125
 126   /// Skip a form's value in \p DebugInfoData at the offset specified by
 127   /// \p OffsetPtr.
 128   ///
 129   /// Skips the bytes for the specified form and updates the offset.
 130   ///
 131   /// \param Form The DW_FORM enumeration that indicates the form to skip.
 132   /// \param DebugInfoData The data where we want to skip the value.
 133   /// \param OffsetPtr A reference to the offset that will be updated.
 134   /// \param FormParams DWARF parameters to help interpret forms.
 135   /// \returns true on success, false if the form was not skipped.
 136   static bool skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
 137                         uint32_t *OffsetPtr,
 138                         const dwarf::FormParams FormParams);
 139
 140 private:
 141   void dumpString(raw_ostream &OS) const;
 142 };
 143
 144 namespace dwarf {
 145
 146 /// Take an optional DWARFFormValue and try to extract a string value from it.
 147 ///
 148 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 149 /// \returns an optional value that contains a value if the form value
 150 /// was valid and was a string.
 151 inline Optional<const char *> toString(const Optional<DWARFFormValue> &V) {
 152   if (V)
 153     return V->getAsCString();
 154   return None;
 155 }
 156
 157 /// Take an optional DWARFFormValue and extract a string value from it.
 158 ///
 159 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 160 /// \param Default the default value to return in case of failure.
 161 /// \returns the string value or Default if the V doesn't have a value or the
 162 /// form value's encoding wasn't a string.
 163 inline const char *toString(const Optional<DWARFFormValue> &V,
 164                             const char *Default) {
 165   return toString(V).getValueOr(Default);
 166 }
 167
 168 /// Take an optional DWARFFormValue and try to extract an unsigned constant.
 169 ///
 170 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 171 /// \returns an optional value that contains a value if the form value
 172 /// was valid and has a unsigned constant form.
 173 inline Optional<uint64_t> toUnsigned(const Optional<DWARFFormValue> &V) {
 174   if (V)
 175     return V->getAsUnsignedConstant();
 176   return None;
 177 }
 178
 179 /// Take an optional DWARFFormValue and extract a unsigned constant.
 180 ///
 181 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 182 /// \param Default the default value to return in case of failure.
 183 /// \returns the extracted unsigned value or Default if the V doesn't have a
 184 /// value or the form value's encoding wasn't an unsigned constant form.
 185 inline uint64_t toUnsigned(const Optional<DWARFFormValue> &V,
 186                            uint64_t Default) {
 187   return toUnsigned(V).getValueOr(Default);
 188 }
 189
 190 /// Take an optional DWARFFormValue and try to extract an reference.
 191 ///
 192 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 193 /// \returns an optional value that contains a value if the form value
 194 /// was valid and has a reference form.
 195 inline Optional<uint64_t> toReference(const Optional<DWARFFormValue> &V) {
 196   if (V)
 197     return V->getAsReference();
 198   return None;
 199 }
 200
 201 /// Take an optional DWARFFormValue and extract a reference.
 202 ///
 203 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 204 /// \param Default the default value to return in case of failure.
 205 /// \returns the extracted reference value or Default if the V doesn't have a
 206 /// value or the form value's encoding wasn't a reference form.
 207 inline uint64_t toReference(const Optional<DWARFFormValue> &V,
 208                             uint64_t Default) {
 209   return toReference(V).getValueOr(Default);
 210 }
 211
 212 /// Take an optional DWARFFormValue and try to extract an signed constant.
 213 ///
 214 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 215 /// \returns an optional value that contains a value if the form value
 216 /// was valid and has a signed constant form.
 217 inline Optional<int64_t> toSigned(const Optional<DWARFFormValue> &V) {
 218   if (V)
 219     return V->getAsSignedConstant();
 220   return None;
 221 }
 222
 223 /// Take an optional DWARFFormValue and extract a signed integer.
 224 ///
 225 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 226 /// \param Default the default value to return in case of failure.
 227 /// \returns the extracted signed integer value or Default if the V doesn't
 228 /// have a value or the form value's encoding wasn't a signed integer form.
 229 inline int64_t toSigned(const Optional<DWARFFormValue> &V, int64_t Default) {
 230   return toSigned(V).getValueOr(Default);
 231 }
 232
 233 /// Take an optional DWARFFormValue and try to extract an address.
 234 ///
 235 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 236 /// \returns an optional value that contains a value if the form value
 237 /// was valid and has a address form.
 238 inline Optional<uint64_t> toAddress(const Optional<DWARFFormValue> &V) {
 239   if (V)
 240     return V->getAsAddress();
 241   return None;
 242 }
 243
 244 inline Optional<SectionedAddress>
 245 toSectionedAddress(const Optional<DWARFFormValue> &V) {
 246   if (V)
 247     return V->getAsSectionedAddress();
 248   return None;
 249 }
 250
 251 /// Take an optional DWARFFormValue and extract a address.
 252 ///
 253 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 254 /// \param Default the default value to return in case of failure.
 255 /// \returns the extracted address value or Default if the V doesn't have a
 256 /// value or the form value's encoding wasn't an address form.
 257 inline uint64_t toAddress(const Optional<DWARFFormValue> &V, uint64_t Default) {
 258   return toAddress(V).getValueOr(Default);
 259 }
 260
 261 /// Take an optional DWARFFormValue and try to extract an section offset.
 262 ///
 263 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 264 /// \returns an optional value that contains a value if the form value
 265 /// was valid and has a section offset form.
 266 inline Optional<uint64_t> toSectionOffset(const Optional<DWARFFormValue> &V) {
 267   if (V)
 268     return V->getAsSectionOffset();
 269   return None;
 270 }
 271
 272 /// Take an optional DWARFFormValue and extract a section offset.
 273 ///
 274 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 275 /// \param Default the default value to return in case of failure.
 276 /// \returns the extracted section offset value or Default if the V doesn't
 277 /// have a value or the form value's encoding wasn't a section offset form.
 278 inline uint64_t toSectionOffset(const Optional<DWARFFormValue> &V,
 279                                 uint64_t Default) {
 280   return toSectionOffset(V).getValueOr(Default);
 281 }
 282
 283 /// Take an optional DWARFFormValue and try to extract block data.
 284 ///
 285 /// \param V and optional DWARFFormValue to attempt to extract the value from.
 286 /// \returns an optional value that contains a value if the form value
 287 /// was valid and has a block form.
 288 inline Optional<ArrayRef<uint8_t>> toBlock(const Optional<DWARFFormValue> &V) {
 289   if (V)
 290     return V->getAsBlock();
 291   return None;
 292 }
 293
 294 } // end namespace dwarf
 295
 296 } // end namespace llvm
 297
 298 #endif // LLVM_DEBUGINFO_DWARFFORMVALUE_H