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/ArmUnwindInfo.h"
21 #include "lldb/Symbol/CompactUnwindInfo.h"
22 
23 // There is one UnwindTable object per ObjectFile.
24 // It contains a list of Unwind objects -- one per function, populated lazily -- for the ObjectFile.
25 // Each Unwind object has multiple UnwindPlans for different scenarios.
26 
27 using namespace lldb;
28 using namespace lldb_private;
29 
30 UnwindTable::UnwindTable (ObjectFile& objfile) :
31     m_object_file (objfile),
32     m_unwinds (),
33     m_initialized (false),
34     m_mutex (),
35     m_eh_frame_up (),
36     m_compact_unwind_up (),
37     m_arm_unwind_up ()
38 {
39 }
40 
41 // We can't do some of this initialization when the ObjectFile is running its ctor; delay doing it
42 // until needed for something.
43 
44 void
45 UnwindTable::Initialize ()
46 {
47     if (m_initialized)
48         return;
49 
50     Mutex::Locker locker(m_mutex);
51 
52     if (m_initialized) // check again once we've acquired the lock
53         return;
54 
55     SectionList* sl = m_object_file.GetSectionList ();
56     if (sl)
57     {
58         SectionSP sect = sl->FindSectionByType (eSectionTypeEHFrame, true);
59         if (sect.get())
60         {
61             m_eh_frame_up.reset(new DWARFCallFrameInfo(m_object_file, sect, eRegisterKindEHFrame, true));
62         }
63         sect = sl->FindSectionByType (eSectionTypeCompactUnwind, true);
64         if (sect.get())
65         {
66             m_compact_unwind_up.reset(new CompactUnwindInfo(m_object_file, sect));
67         }
68         sect = sl->FindSectionByType (eSectionTypeARMexidx, true);
69         if (sect.get())
70         {
71             SectionSP sect_extab = sl->FindSectionByType (eSectionTypeARMextab, true);
72             if (sect_extab.get())
73             {
74                 m_arm_unwind_up.reset(new ArmUnwindInfo(m_object_file, sect, sect_extab));
75             }
76         }
77     }
78 
79     m_initialized = true;
80 }
81 
82 UnwindTable::~UnwindTable ()
83 {
84 }
85 
86 FuncUnwindersSP
87 UnwindTable::GetFuncUnwindersContainingAddress (const Address& addr, SymbolContext &sc)
88 {
89     FuncUnwindersSP no_unwind_found;
90 
91     Initialize();
92 
93     Mutex::Locker locker(m_mutex);
94 
95     // There is an UnwindTable per object file, so we can safely use file handles
96     addr_t file_addr = addr.GetFileAddress();
97     iterator end = m_unwinds.end ();
98     iterator insert_pos = end;
99     if (!m_unwinds.empty())
100     {
101         insert_pos = m_unwinds.lower_bound (file_addr);
102         iterator pos = insert_pos;
103         if ((pos == m_unwinds.end ()) || (pos != m_unwinds.begin() && pos->second->GetFunctionStartAddress() != addr))
104             --pos;
105 
106         if (pos->second->ContainsAddress (addr))
107             return pos->second;
108     }
109 
110     AddressRange range;
111     if (!sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0, false, range) || !range.GetBaseAddress().IsValid())
112     {
113         // Does the eh_frame unwind info has a function bounds for this addr?
114         if (m_eh_frame_up == nullptr || !m_eh_frame_up->GetAddressRange (addr, range))
115         {
116             return no_unwind_found;
117         }
118     }
119 
120     FuncUnwindersSP func_unwinder_sp(new FuncUnwinders(*this, range));
121     m_unwinds.insert (insert_pos, std::make_pair(range.GetBaseAddress().GetFileAddress(), func_unwinder_sp));
122 //    StreamFile s(stdout, false);
123 //    Dump (s);
124     return func_unwinder_sp;
125 }
126 
127 // Ignore any existing FuncUnwinders for this function, create a new one and don't add it to the
128 // UnwindTable.  This is intended for use by target modules show-unwind where we want to create
129 // new UnwindPlans, not re-use existing ones.
130 
131 FuncUnwindersSP
132 UnwindTable::GetUncachedFuncUnwindersContainingAddress (const Address& addr, SymbolContext &sc)
133 {
134     FuncUnwindersSP no_unwind_found;
135     Initialize();
136 
137     AddressRange range;
138     if (!sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0, false, range) || !range.GetBaseAddress().IsValid())
139     {
140         // Does the eh_frame unwind info has a function bounds for this addr?
141         if (m_eh_frame_up == nullptr || !m_eh_frame_up->GetAddressRange (addr, range))
142         {
143             return no_unwind_found;
144         }
145     }
146 
147     FuncUnwindersSP func_unwinder_sp(new FuncUnwinders(*this, range));
148     return func_unwinder_sp;
149 }
150 
151 
152 void
153 UnwindTable::Dump (Stream &s)
154 {
155     Mutex::Locker locker(m_mutex);
156     s.Printf("UnwindTable for '%s':\n", m_object_file.GetFileSpec().GetPath().c_str());
157     const_iterator begin = m_unwinds.begin();
158     const_iterator end = m_unwinds.end();
159     for (const_iterator pos = begin; pos != end; ++pos)
160     {
161         s.Printf ("[%u] 0x%16.16" PRIx64 "\n", (unsigned)std::distance (begin, pos), pos->first);
162     }
163     s.EOL();
164 }
165 
166 DWARFCallFrameInfo *
167 UnwindTable::GetEHFrameInfo ()
168 {
169     Initialize();
170     return m_eh_frame_up.get();
171 }
172 
173 CompactUnwindInfo *
174 UnwindTable::GetCompactUnwindInfo ()
175 {
176     Initialize();
177     return m_compact_unwind_up.get();
178 }
179 
180 ArmUnwindInfo *
181 UnwindTable::GetArmUnwindInfo ()
182 {
183     Initialize();
184     return m_arm_unwind_up.get();
185 }
186 
187 bool
188 UnwindTable::GetArchitecture (lldb_private::ArchSpec &arch)
189 {
190     return m_object_file.GetArchitecture (arch);
191 }
192