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