lib/DebugInfo/DWARF/DWARFDataExtractor.cpp

   1 //===- DWARFDataExtractor.cpp ---------------------------------------------===//
   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 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
  10 #include "llvm/BinaryFormat/Dwarf.h"
  11 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
  12
  13 using namespace llvm;
  14
  15 uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint64_t *Off,
  16                                                uint64_t *SecNdx,
  17                                                Error *Err) const {
  18   if (SecNdx)
  19     *SecNdx = object::SectionedAddress::UndefSection;
  20   if (!Section)
  21     return getUnsigned(Off, Size, Err);
  22   Optional<RelocAddrEntry> E = Obj->find(*Section, *Off);
  23   uint64_t A = getUnsigned(Off, Size, Err);
  24   if (!E)
  25     return A;
  26   if (SecNdx)
  27     *SecNdx = E->SectionIndex;
  28   uint64_t R = E->Resolver(E->Reloc, E->SymbolValue, A);
  29   if (E->Reloc2)
  30     R = E->Resolver(*E->Reloc2, E->SymbolValue2, R);
  31   return R;
  32 }
  33
  34 Optional<uint64_t>
  35 DWARFDataExtractor::getEncodedPointer(uint64_t *Offset, uint8_t Encoding,
  36                                       uint64_t PCRelOffset) const {
  37   if (Encoding == dwarf::DW_EH_PE_omit)
  38     return None;
  39
  40   uint64_t Result = 0;
  41   uint64_t OldOffset = *Offset;
  42   // First get value
  43   switch (Encoding & 0x0F) {
  44   case dwarf::DW_EH_PE_absptr:
  45     switch (getAddressSize()) {
  46     case 2:
  47     case 4:
  48     case 8:
  49       Result = getUnsigned(Offset, getAddressSize());
  50       break;
  51     default:
  52       return None;
  53     }
  54     break;
  55   case dwarf::DW_EH_PE_uleb128:
  56     Result = getULEB128(Offset);
  57     break;
  58   case dwarf::DW_EH_PE_sleb128:
  59     Result = getSLEB128(Offset);
  60     break;
  61   case dwarf::DW_EH_PE_udata2:
  62     Result = getUnsigned(Offset, 2);
  63     break;
  64   case dwarf::DW_EH_PE_udata4:
  65     Result = getUnsigned(Offset, 4);
  66     break;
  67   case dwarf::DW_EH_PE_udata8:
  68     Result = getUnsigned(Offset, 8);
  69     break;
  70   case dwarf::DW_EH_PE_sdata2:
  71     Result = getSigned(Offset, 2);
  72     break;
  73   case dwarf::DW_EH_PE_sdata4:
  74     Result = getSigned(Offset, 4);
  75     break;
  76   case dwarf::DW_EH_PE_sdata8:
  77     Result = getSigned(Offset, 8);
  78     break;
  79   default:
  80     return None;
  81   }
  82   // Then add relative offset, if required
  83   switch (Encoding & 0x70) {
  84   case dwarf::DW_EH_PE_absptr:
  85     // do nothing
  86     break;
  87   case dwarf::DW_EH_PE_pcrel:
  88     Result += PCRelOffset;
  89     break;
  90   case dwarf::DW_EH_PE_datarel:
  91   case dwarf::DW_EH_PE_textrel:
  92   case dwarf::DW_EH_PE_funcrel:
  93   case dwarf::DW_EH_PE_aligned:
  94   default:
  95     *Offset = OldOffset;
  96     return None;
  97   }
  98
  99   return Result;
 100 }