src/llvm/lib/DebugInfo/DWARFDebugArangeSet.cpp

   1 //===-- DWARFDebugArangeSet.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/DWARFDebugArangeSet.h"
  11 #include "llvm/Support/Format.h"
  12 #include "llvm/Support/raw_ostream.h"
  13 #include <algorithm>
  14 #include <cassert>
  15 using namespace llvm;
  16
  17 void DWARFDebugArangeSet::clear() {
  18   Offset = -1U;
  19   std::memset(&HeaderData, 0, sizeof(Header));
  20   ArangeDescriptors.clear();
  21 }
  22
  23 bool
  24 DWARFDebugArangeSet::extract(DataExtractor data, uint32_t *offset_ptr) {
  25   if (data.isValidOffset(*offset_ptr)) {
  26     ArangeDescriptors.clear();
  27     Offset = *offset_ptr;
  28
  29     // 7.20 Address Range Table
  30     //
  31     // Each set of entries in the table of address ranges contained in
  32     // the .debug_aranges section begins with a header consisting of: a
  33     // 4-byte length containing the length of the set of entries for this
  34     // compilation unit, not including the length field itself; a 2-byte
  35     // version identifier containing the value 2 for DWARF Version 2; a
  36     // 4-byte offset into the.debug_infosection; a 1-byte unsigned integer
  37     // containing the size in bytes of an address (or the offset portion of
  38     // an address for segmented addressing) on the target system; and a
  39     // 1-byte unsigned integer containing the size in bytes of a segment
  40     // descriptor on the target system. This header is followed by a series
  41     // of tuples. Each tuple consists of an address and a length, each in
  42     // the size appropriate for an address on the target architecture.
  43     HeaderData.Length = data.getU32(offset_ptr);
  44     HeaderData.Version = data.getU16(offset_ptr);
  45     HeaderData.CuOffset = data.getU32(offset_ptr);
  46     HeaderData.AddrSize = data.getU8(offset_ptr);
  47     HeaderData.SegSize = data.getU8(offset_ptr);
  48
  49     // Perform basic validation of the header fields.
  50     if (!data.isValidOffsetForDataOfSize(Offset, HeaderData.Length) ||
  51         (HeaderData.AddrSize != 4 && HeaderData.AddrSize != 8)) {
  52       clear();
  53       return false;
  54     }
  55
  56     // The first tuple following the header in each set begins at an offset
  57     // that is a multiple of the size of a single tuple (that is, twice the
  58     // size of an address). The header is padded, if necessary, to the
  59     // appropriate boundary.
  60     const uint32_t header_size = *offset_ptr - Offset;
  61     const uint32_t tuple_size = HeaderData.AddrSize * 2;
  62     uint32_t first_tuple_offset = 0;
  63     while (first_tuple_offset < header_size)
  64       first_tuple_offset += tuple_size;
  65
  66     *offset_ptr = Offset + first_tuple_offset;
  67
  68     Descriptor arangeDescriptor;
  69
  70     static_assert(sizeof(arangeDescriptor.Address) ==
  71                       sizeof(arangeDescriptor.Length),
  72                   "Different datatypes for addresses and sizes!");
  73     assert(sizeof(arangeDescriptor.Address) >= HeaderData.AddrSize);
  74
  75     while (data.isValidOffset(*offset_ptr)) {
  76       arangeDescriptor.Address = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
  77       arangeDescriptor.Length = data.getUnsigned(offset_ptr, HeaderData.AddrSize);
  78
  79       // Each set of tuples is terminated by a 0 for the address and 0
  80       // for the length.
  81       if (arangeDescriptor.Address || arangeDescriptor.Length)
  82         ArangeDescriptors.push_back(arangeDescriptor);
  83       else
  84         break; // We are done if we get a zero address and length
  85     }
  86
  87     return !ArangeDescriptors.empty();
  88   }
  89   return false;
  90 }
  91
  92 void DWARFDebugArangeSet::dump(raw_ostream &OS) const {
  93   OS << format("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, ",
  94                HeaderData.Length, HeaderData.Version)
  95      << format("cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n",
  96                HeaderData.CuOffset, HeaderData.AddrSize, HeaderData.SegSize);
  97
  98   const uint32_t hex_width = HeaderData.AddrSize * 2;
  99   for (const auto &Desc : ArangeDescriptors) {
 100     OS << format("[0x%*.*" PRIx64 " -", hex_width, hex_width, Desc.Address)
 101        << format(" 0x%*.*" PRIx64 ")\n",
 102                  hex_width, hex_width, Desc.getEndAddress());
 103   }
 104 }