1 //===- DWARFDataExtractor.cpp ---------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
11 #include "llvm/BinaryFormat/Dwarf.h"
12 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
13 
14 using namespace llvm;
15 
16 uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint32_t *Off,
17                                                uint64_t *SecNdx) const {
18   if (SecNdx)
19     *SecNdx = -1ULL;
20   if (!Section)
21     return getUnsigned(Off, Size);
22   Optional<RelocAddrEntry> Rel = Obj->find(*Section, *Off);
23   if (!Rel)
24     return getUnsigned(Off, Size);
25   if (SecNdx)
26     *SecNdx = Rel->SectionIndex;
27   return getUnsigned(Off, Size) + Rel->Value;
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