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