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