1 //===-- DWARFCompileUnit.cpp ------------------------------------*- C++ -*-===//
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 "DWARFCompileUnit.h"
11 
12 #include "SymbolFileDWARF.h"
13 #include "lldb/Utility/Stream.h"
14 
15 using namespace lldb;
16 using namespace lldb_private;
17 
18 extern int g_verbose;
19 
20 DWARFCompileUnit::DWARFCompileUnit(SymbolFileDWARF *dwarf2Data)
21     : DWARFUnit(dwarf2Data) {}
22 
23 DWARFUnitSP DWARFCompileUnit::Extract(SymbolFileDWARF *dwarf2Data,
24                                       const DWARFDataExtractor &debug_info,
25                                       lldb::offset_t *offset_ptr) {
26   // std::make_shared would require the ctor to be public.
27   std::shared_ptr<DWARFCompileUnit> cu_sp(new DWARFCompileUnit(dwarf2Data));
28 
29   cu_sp->m_offset = *offset_ptr;
30 
31   if (debug_info.ValidOffset(*offset_ptr)) {
32     dw_offset_t abbr_offset;
33     const DWARFDebugAbbrev *abbr = dwarf2Data->DebugAbbrev();
34     cu_sp->m_length = debug_info.GetDWARFInitialLength(offset_ptr);
35     cu_sp->m_is_dwarf64 = debug_info.IsDWARF64();
36     cu_sp->m_version = debug_info.GetU16(offset_ptr);
37 
38     if (cu_sp->m_version == 5) {
39       cu_sp->m_unit_type = debug_info.GetU8(offset_ptr);
40       cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
41       abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
42 
43       if (cu_sp->m_unit_type == llvm::dwarf::DW_UT_skeleton)
44         cu_sp->m_dwo_id = debug_info.GetU64(offset_ptr);
45     } else {
46       abbr_offset = debug_info.GetDWARFOffset(offset_ptr);
47       cu_sp->m_addr_size = debug_info.GetU8(offset_ptr);
48     }
49 
50     bool length_OK =
51         debug_info.ValidOffset(cu_sp->GetNextCompileUnitOffset() - 1);
52     bool version_OK = SymbolFileDWARF::SupportedVersion(cu_sp->m_version);
53     bool abbr_offset_OK =
54         dwarf2Data->get_debug_abbrev_data().ValidOffset(abbr_offset);
55     bool addr_size_OK = (cu_sp->m_addr_size == 4) || (cu_sp->m_addr_size == 8);
56 
57     if (length_OK && version_OK && addr_size_OK && abbr_offset_OK &&
58         abbr != NULL) {
59       cu_sp->m_abbrevs = abbr->GetAbbreviationDeclarationSet(abbr_offset);
60       return cu_sp;
61     }
62 
63     // reset the offset to where we tried to parse from if anything went wrong
64     *offset_ptr = cu_sp->m_offset;
65   }
66 
67   return nullptr;
68 }
69 
70 void DWARFCompileUnit::Dump(Stream *s) const {
71   s->Printf("0x%8.8x: Compile Unit: length = 0x%8.8x, version = 0x%4.4x, "
72             "abbr_offset = 0x%8.8x, addr_size = 0x%2.2x (next CU at "
73             "{0x%8.8x})\n",
74             m_offset, m_length, m_version, GetAbbrevOffset(), m_addr_size,
75             GetNextCompileUnitOffset());
76 }
77 
78 uint32_t DWARFCompileUnit::GetHeaderByteSize() const {
79   if (m_version < 5)
80     return m_is_dwarf64 ? 23 : 11;
81 
82   switch (m_unit_type) {
83   case llvm::dwarf::DW_UT_compile:
84   case llvm::dwarf::DW_UT_partial:
85     return 12;
86   case llvm::dwarf::DW_UT_skeleton:
87   case llvm::dwarf::DW_UT_split_compile:
88     return 20;
89   case llvm::dwarf::DW_UT_type:
90   case llvm::dwarf::DW_UT_split_type:
91     return 24;
92   }
93   llvm_unreachable("invalid UnitType.");
94 }
95 
96 const lldb_private::DWARFDataExtractor &DWARFCompileUnit::GetData() const {
97   return m_dwarf->get_debug_info_data();
98 }
99