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 }
101