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      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 void DWARFDebugRangeList::clear() {
     20   Offset = -1ULL;
     21   AddressSize = 0;
     22   Entries.clear();
     23 }
     24 
     25 Error DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
     26                                    uint64_t *offset_ptr) {
     27   clear();
     28   if (!data.isValidOffset(*offset_ptr))
     29     return createStringError(errc::invalid_argument,
     30                        "invalid range list offset 0x%" PRIx64, *offset_ptr);
     31 
     32   AddressSize = data.getAddressSize();
     33   if (AddressSize != 4 && AddressSize != 8)
     34     return createStringError(errc::invalid_argument,
     35                        "invalid address size: %" PRIu8, AddressSize);
     36   Offset = *offset_ptr;
     37   while (true) {
     38     RangeListEntry Entry;
     39     Entry.SectionIndex = -1ULL;
     40 
     41     uint64_t prev_offset = *offset_ptr;
     42     Entry.StartAddress = data.getRelocatedAddress(offset_ptr);
     43     Entry.EndAddress =
     44         data.getRelocatedAddress(offset_ptr, &Entry.SectionIndex);
     45 
     46     // Check that both values were extracted correctly.
     47     if (*offset_ptr != prev_offset + 2 * AddressSize) {
     48       clear();
     49       return createStringError(errc::invalid_argument,
     50                          "invalid range list entry at offset 0x%" PRIx64,
     51                          prev_offset);
     52     }
     53     if (Entry.isEndOfListEntry())
     54       break;
     55     Entries.push_back(Entry);
     56   }
     57   return Error::success();
     58 }
     59 
     60 void DWARFDebugRangeList::dump(raw_ostream &OS) const {
     61   for (const RangeListEntry &RLE : Entries) {
     62     const char *format_str =
     63         (AddressSize == 4 ? "%08" PRIx64 " %08" PRIx64 " %08" PRIx64 "\n"
     64                           : "%08" PRIx64 " %016" PRIx64 " %016" PRIx64 "\n");
     65     OS << format(format_str, Offset, RLE.StartAddress, RLE.EndAddress);
     66   }
     67   OS << format("%08" PRIx64 " <End of list>\n", Offset);
     68 }
     69 
     70 DWARFAddressRangesVector DWARFDebugRangeList::getAbsoluteRanges(
     71     llvm::Optional<object::SectionedAddress> BaseAddr) const {
     72   DWARFAddressRangesVector Res;
     73   // debug_addr can't use the max integer tombstone because that's used for the
     74   // base address specifier entry - so use max-1.
     75   uint64_t Tombstone = dwarf::computeTombstoneAddress(AddressSize) - 1;
     76   for (const RangeListEntry &RLE : Entries) {
     77     if (RLE.isBaseAddressSelectionEntry(AddressSize)) {
     78       BaseAddr = {RLE.EndAddress, RLE.SectionIndex};
     79       continue;
     80     }
     81 
     82     DWARFAddressRange E;
     83     E.LowPC = RLE.StartAddress;
     84     if (E.LowPC == Tombstone)
     85       continue;
     86     E.HighPC = RLE.EndAddress;
     87     E.SectionIndex = RLE.SectionIndex;
     88     // Base address of a range list entry is determined by the closest preceding
     89     // base address selection entry in the same range list. It defaults to the
     90     // base address of the compilation unit if there is no such entry.
     91     if (BaseAddr) {
     92       if (BaseAddr->Address == Tombstone)
     93         continue;
     94       E.LowPC += BaseAddr->Address;
     95       E.HighPC += BaseAddr->Address;
     96       if (E.SectionIndex == -1ULL)
     97         E.SectionIndex = BaseAddr->SectionIndex;
     98     }
     99     Res.push_back(E);
    100   }
    101   return Res;
    102 }
    103