1 //===- DWARFDebugRangesList.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/DWARFDebugRangeList.h"
10 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
11 #include "llvm/Support/Errc.h"
12 #include "llvm/Support/Format.h"
13 #include "llvm/Support/raw_ostream.h"
14 #include <cinttypes>
15 #include <cstdint>
16 
17 using namespace llvm;
18 
19 bool DWARFDebugRangeList::RangeListEntry::isBaseAddressSelectionEntry(
20     uint8_t AddressSize) const {
21   assert(DWARFContext::isAddressSizeSupported(AddressSize));
22   return StartAddress == dwarf::computeTombstoneAddress(AddressSize);
23 }
24 
25 void DWARFDebugRangeList::clear() {
26   Offset = -1ULL;
27   AddressSize = 0;
28   Entries.clear();
29 }
30 
31 Error DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
32                                    uint64_t *offset_ptr) {
33   clear();
34   if (!data.isValidOffset(*offset_ptr))
35     return createStringError(errc::invalid_argument,
36                        "invalid range list offset 0x%" PRIx64, *offset_ptr);
37 
38   AddressSize = data.getAddressSize();
39   if (Error SizeErr = DWARFContext::checkAddressSizeSupported(
40           AddressSize, errc::invalid_argument,
41           "range list at offset 0x%" PRIx64, *offset_ptr))
42     return SizeErr;
43   Offset = *offset_ptr;
44   while (true) {
45     RangeListEntry Entry;
46     Entry.SectionIndex = -1ULL;
47 
48     uint64_t prev_offset = *offset_ptr;
49     Entry.StartAddress = data.getRelocatedAddress(offset_ptr);
50     Entry.EndAddress =
51         data.getRelocatedAddress(offset_ptr, &Entry.SectionIndex);
52 
53     // Check that both values were extracted correctly.
54     if (*offset_ptr != prev_offset + 2 * AddressSize) {
55       clear();
56       return createStringError(errc::invalid_argument,
57                          "invalid range list entry at offset 0x%" PRIx64,
58                          prev_offset);
59     }
60     if (Entry.isEndOfListEntry())
61       break;
62     Entries.push_back(Entry);
63   }
64   return Error::success();
65 }
66 
67 void DWARFDebugRangeList::dump(raw_ostream &OS) const {
68   const char *AddrFmt;
69   switch (AddressSize) {
70   case 2:
71     AddrFmt = "%08" PRIx64 " %04" PRIx64 " %04" PRIx64 "\n";
72     break;
73   case 4:
74     AddrFmt = "%08" PRIx64 " %08" PRIx64 " %08" PRIx64 "\n";
75     break;
76   case 8:
77     AddrFmt = "%08" PRIx64 " %016" PRIx64 " %016" PRIx64 "\n";
78     break;
79   default:
80     llvm_unreachable("unsupported address size");
81   }
82   for (const RangeListEntry &RLE : Entries)
83     OS << format(AddrFmt, Offset, RLE.StartAddress, RLE.EndAddress);
84   OS << format("%08" PRIx64 " <End of list>\n", Offset);
85 }
86 
87 DWARFAddressRangesVector DWARFDebugRangeList::getAbsoluteRanges(
88     llvm::Optional<object::SectionedAddress> BaseAddr) const {
89   DWARFAddressRangesVector Res;
90   // debug_addr can't use the max integer tombstone because that's used for the
91   // base address specifier entry - so use max-1.
92   uint64_t Tombstone = dwarf::computeTombstoneAddress(AddressSize) - 1;
93   for (const RangeListEntry &RLE : Entries) {
94     if (RLE.isBaseAddressSelectionEntry(AddressSize)) {
95       BaseAddr = {RLE.EndAddress, RLE.SectionIndex};
96       continue;
97     }
98 
99     DWARFAddressRange E;
100     E.LowPC = RLE.StartAddress;
101     if (E.LowPC == Tombstone)
102       continue;
103     E.HighPC = RLE.EndAddress;
104     E.SectionIndex = RLE.SectionIndex;
105     // Base address of a range list entry is determined by the closest preceding
106     // base address selection entry in the same range list. It defaults to the
107     // base address of the compilation unit if there is no such entry.
108     if (BaseAddr) {
109       if (BaseAddr->Address == Tombstone)
110         continue;
111       E.LowPC += BaseAddr->Address;
112       E.HighPC += BaseAddr->Address;
113       if (E.SectionIndex == -1ULL)
114         E.SectionIndex = BaseAddr->SectionIndex;
115     }
116     Res.push_back(E);
117   }
118   return Res;
119 }
120