1 //===-- UnwindTable.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 "lldb/Symbol/UnwindTable.h"
11
12 #include <stdio.h>
13
14 #include "lldb/Core/Module.h"
15 #include "lldb/Core/Section.h"
16 #include "lldb/Symbol/ObjectFile.h"
17 #include "lldb/Symbol/FuncUnwinders.h"
18 #include "lldb/Symbol/SymbolContext.h"
19 #include "lldb/Symbol/DWARFCallFrameInfo.h"
20 #include "lldb/Symbol/CompactUnwindInfo.h"
21
22 // There is one UnwindTable object per ObjectFile.
23 // It contains a list of Unwind objects -- one per function, populated lazily -- for the ObjectFile.
24 // Each Unwind object has multiple UnwindPlans for different scenarios.
25
26 using namespace lldb;
27 using namespace lldb_private;
28
UnwindTable(ObjectFile & objfile)29 UnwindTable::UnwindTable (ObjectFile& objfile) :
30 m_object_file (objfile),
31 m_unwinds (),
32 m_initialized (false),
33 m_mutex (),
34 m_eh_frame (nullptr),
35 m_compact_unwind (nullptr)
36 {
37 }
38
39 // We can't do some of this initialization when the ObjectFile is running its ctor; delay doing it
40 // until needed for something.
41
42 void
Initialize()43 UnwindTable::Initialize ()
44 {
45 if (m_initialized)
46 return;
47
48 Mutex::Locker locker(m_mutex);
49
50 if (m_initialized) // check again once we've acquired the lock
51 return;
52
53 SectionList* sl = m_object_file.GetSectionList ();
54 if (sl)
55 {
56 SectionSP sect = sl->FindSectionByType (eSectionTypeEHFrame, true);
57 if (sect.get())
58 {
59 m_eh_frame = new DWARFCallFrameInfo(m_object_file, sect, eRegisterKindGCC, true);
60 }
61 sect = sl->FindSectionByType (eSectionTypeCompactUnwind, true);
62 if (sect.get())
63 {
64 m_compact_unwind = new CompactUnwindInfo(m_object_file, sect);
65 }
66 }
67
68 m_initialized = true;
69 }
70
~UnwindTable()71 UnwindTable::~UnwindTable ()
72 {
73 if (m_eh_frame)
74 delete m_eh_frame;
75 }
76
77 FuncUnwindersSP
GetFuncUnwindersContainingAddress(const Address & addr,SymbolContext & sc)78 UnwindTable::GetFuncUnwindersContainingAddress (const Address& addr, SymbolContext &sc)
79 {
80 FuncUnwindersSP no_unwind_found;
81
82 Initialize();
83
84 Mutex::Locker locker(m_mutex);
85
86 // There is an UnwindTable per object file, so we can safely use file handles
87 addr_t file_addr = addr.GetFileAddress();
88 iterator end = m_unwinds.end ();
89 iterator insert_pos = end;
90 if (!m_unwinds.empty())
91 {
92 insert_pos = m_unwinds.lower_bound (file_addr);
93 iterator pos = insert_pos;
94 if ((pos == m_unwinds.end ()) || (pos != m_unwinds.begin() && pos->second->GetFunctionStartAddress() != addr))
95 --pos;
96
97 if (pos->second->ContainsAddress (addr))
98 return pos->second;
99 }
100
101 AddressRange range;
102 if (!sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0, false, range) || !range.GetBaseAddress().IsValid())
103 {
104 // Does the eh_frame unwind info has a function bounds for this addr?
105 if (m_eh_frame == nullptr || !m_eh_frame->GetAddressRange (addr, range))
106 {
107 return no_unwind_found;
108 }
109 }
110
111 FuncUnwindersSP func_unwinder_sp(new FuncUnwinders(*this, range));
112 m_unwinds.insert (insert_pos, std::make_pair(range.GetBaseAddress().GetFileAddress(), func_unwinder_sp));
113 // StreamFile s(stdout, false);
114 // Dump (s);
115 return func_unwinder_sp;
116 }
117
118 // Ignore any existing FuncUnwinders for this function, create a new one and don't add it to the
119 // UnwindTable. This is intended for use by target modules show-unwind where we want to create
120 // new UnwindPlans, not re-use existing ones.
121
122 FuncUnwindersSP
GetUncachedFuncUnwindersContainingAddress(const Address & addr,SymbolContext & sc)123 UnwindTable::GetUncachedFuncUnwindersContainingAddress (const Address& addr, SymbolContext &sc)
124 {
125 FuncUnwindersSP no_unwind_found;
126 Initialize();
127
128 AddressRange range;
129 if (!sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0, false, range) || !range.GetBaseAddress().IsValid())
130 {
131 // Does the eh_frame unwind info has a function bounds for this addr?
132 if (m_eh_frame == nullptr || !m_eh_frame->GetAddressRange (addr, range))
133 {
134 return no_unwind_found;
135 }
136 }
137
138 FuncUnwindersSP func_unwinder_sp(new FuncUnwinders(*this, range));
139 return func_unwinder_sp;
140 }
141
142
143 void
Dump(Stream & s)144 UnwindTable::Dump (Stream &s)
145 {
146 Mutex::Locker locker(m_mutex);
147 s.Printf("UnwindTable for '%s':\n", m_object_file.GetFileSpec().GetPath().c_str());
148 const_iterator begin = m_unwinds.begin();
149 const_iterator end = m_unwinds.end();
150 for (const_iterator pos = begin; pos != end; ++pos)
151 {
152 s.Printf ("[%u] 0x%16.16" PRIx64 "\n", (unsigned)std::distance (begin, pos), pos->first);
153 }
154 s.EOL();
155 }
156
157 DWARFCallFrameInfo *
GetEHFrameInfo()158 UnwindTable::GetEHFrameInfo ()
159 {
160 Initialize();
161 return m_eh_frame;
162 }
163
164 CompactUnwindInfo *
GetCompactUnwindInfo()165 UnwindTable::GetCompactUnwindInfo ()
166 {
167 Initialize();
168 return m_compact_unwind;
169 }
170
171 bool
GetArchitecture(lldb_private::ArchSpec & arch)172 UnwindTable::GetArchitecture (lldb_private::ArchSpec &arch)
173 {
174 return m_object_file.GetArchitecture (arch);
175 }
176