1 //===-- DWARFCompileUnit.cpp ------------------------------------*- C++ -*-===//
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 "DWARFCompileUnit.h"
10 
11 #include "SymbolFileDWARF.h"
12 #include "lldb/Utility/Stream.h"
13 #include "llvm/Object/Error.h"
14 
15 using namespace lldb;
16 using namespace lldb_private;
17 
18 DWARFCompileUnit::DWARFCompileUnit(SymbolFileDWARF *dwarf2Data)
19     : DWARFUnit(dwarf2Data) {}
20 
21 llvm::Expected<DWARFUnitSP>
22 DWARFCompileUnit::extract(SymbolFileDWARF *dwarf2Data,
23                           const DWARFDataExtractor &debug_info,
24                           lldb::offset_t *offset_ptr) {
25   assert(debug_info.ValidOffset(*offset_ptr));
26 
27   // std::make_shared would require the ctor to be public.
28   std::shared_ptr<DWARFCompileUnit> cu_sp(new DWARFCompileUnit(dwarf2Data));
29 
30   cu_sp->m_offset = *offset_ptr;
31 
32   dw_offset_t abbr_offset;
33   const DWARFDebugAbbrev *abbr = dwarf2Data->DebugAbbrev();
34   if (!abbr)
35     return llvm::make_error<llvm::object::GenericBinaryError>(
36         "No debug_abbrev data");
37 
38   cu_sp->m_length = debug_info.GetDWARFInitialLength(offset_ptr);
39   cu_sp->m_version = debug_info.GetU16(offset_ptr);
40 
41   if (cu_sp->m_version == 5) {
42     cu_sp->m_unit_type = debug_info.GetU8(offset_ptr);
43     cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
44     abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
45 
46     if (cu_sp->m_unit_type == llvm::dwarf::DW_UT_skeleton)
47       cu_sp->m_dwo_id = debug_info.GetU64(offset_ptr);
48   } else {
49     abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
50     cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
51   }
52 
53   bool length_OK =
54       debug_info.ValidOffset(cu_sp->GetNextCompileUnitOffset() - 1);
55   bool version_OK = SymbolFileDWARF::SupportedVersion(cu_sp->m_version);
56   bool abbr_offset_OK =
57       dwarf2Data->get_debug_abbrev_data().ValidOffset(abbr_offset);
58   bool addr_size_OK = (cu_sp->m_addr_size == 4) || (cu_sp->m_addr_size == 8);
59 
60   if (!length_OK)
61     return llvm::make_error<llvm::object::GenericBinaryError>(
62         "Invalid compile unit length");
63   if (!version_OK)
64     return llvm::make_error<llvm::object::GenericBinaryError>(
65         "Unsupported compile unit version");
66   if (!abbr_offset_OK)
67     return llvm::make_error<llvm::object::GenericBinaryError>(
68         "Abbreviation offset for compile unit is not valid");
69   if (!addr_size_OK)
70     return llvm::make_error<llvm::object::GenericBinaryError>(
71         "Invalid compile unit address size");
72 
73   cu_sp->m_abbrevs = abbr->GetAbbreviationDeclarationSet(abbr_offset);
74   if (!cu_sp->m_abbrevs)
75     return llvm::make_error<llvm::object::GenericBinaryError>(
76         "No abbrev exists at the specified offset.");
77 
78   return cu_sp;
79 }
80 
81 void DWARFCompileUnit::Dump(Stream *s) const {
82   s->Printf("0x%8.8x: Compile Unit: length = 0x%8.8x, version = 0x%4.4x, "
83             "abbr_offset = 0x%8.8x, addr_size = 0x%2.2x (next CU at "
84             "{0x%8.8x})\n",
85             m_offset, m_length, m_version, GetAbbrevOffset(), m_addr_size,
86             GetNextCompileUnitOffset());
87 }
88 
89 uint32_t DWARFCompileUnit::GetHeaderByteSize() const {
90   if (m_version < 5)
91     return 11;
92 
93   switch (m_unit_type) {
94   case llvm::dwarf::DW_UT_compile:
95   case llvm::dwarf::DW_UT_partial:
96     return 12;
97   case llvm::dwarf::DW_UT_skeleton:
98   case llvm::dwarf::DW_UT_split_compile:
99     return 20;
100   case llvm::dwarf::DW_UT_type:
101   case llvm::dwarf::DW_UT_split_type:
102     return 24;
103   }
104   llvm_unreachable("invalid UnitType.");
105 }
106 
107 const lldb_private::DWARFDataExtractor &DWARFCompileUnit::GetData() const {
108   return m_dwarf->get_debug_info_data();
109 }
110