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/Target/UnwindAssembly.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
26using namespace lldb;
27using namespace lldb_private;
28
29UnwindTable::UnwindTable (ObjectFile& objfile) :
30    m_object_file (objfile),
31    m_unwinds (),
32    m_initialized (false),
33    m_assembly_profiler (NULL),
34    m_eh_frame (NULL)
35{
36}
37
38// We can't do some of this initialization when the ObjectFile is running its ctor; delay doing it
39// until needed for something.
40
41void
42UnwindTable::Initialize ()
43{
44    if (m_initialized)
45        return;
46
47    SectionList* sl = m_object_file.GetSectionList ();
48    if (sl)
49    {
50        SectionSP sect = sl->FindSectionByType (eSectionTypeEHFrame, true);
51        if (sect.get())
52        {
53            m_eh_frame = new DWARFCallFrameInfo(m_object_file, sect, eRegisterKindGCC, true);
54        }
55    }
56
57    ArchSpec arch;
58    if (m_object_file.GetArchitecture (arch))
59    {
60        m_assembly_profiler = UnwindAssembly::FindPlugin (arch);
61        m_initialized = true;
62    }
63}
64
65UnwindTable::~UnwindTable ()
66{
67    if (m_eh_frame)
68        delete m_eh_frame;
69}
70
71FuncUnwindersSP
72UnwindTable::GetFuncUnwindersContainingAddress (const Address& addr, SymbolContext &sc)
73{
74    FuncUnwindersSP no_unwind_found;
75
76    Initialize();
77
78    // There is an UnwindTable per object file, so we can safely use file handles
79    addr_t file_addr = addr.GetFileAddress();
80    iterator end = m_unwinds.end ();
81    iterator insert_pos = end;
82    if (!m_unwinds.empty())
83    {
84        insert_pos = m_unwinds.lower_bound (file_addr);
85        iterator pos = insert_pos;
86        if ((pos == m_unwinds.end ()) || (pos != m_unwinds.begin() && pos->second->GetFunctionStartAddress() != addr))
87            --pos;
88
89        if (pos->second->ContainsAddress (addr))
90            return pos->second;
91    }
92
93    AddressRange range;
94    if (!sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0, false, range) || !range.GetBaseAddress().IsValid())
95    {
96        // Does the eh_frame unwind info has a function bounds for this addr?
97        if (m_eh_frame == NULL || !m_eh_frame->GetAddressRange (addr, range))
98        {
99            return no_unwind_found;
100        }
101    }
102
103    FuncUnwindersSP func_unwinder_sp(new FuncUnwinders(*this, m_assembly_profiler, range));
104    m_unwinds.insert (insert_pos, std::make_pair(range.GetBaseAddress().GetFileAddress(), func_unwinder_sp));
105//    StreamFile s(stdout);
106//    Dump (s);
107    return func_unwinder_sp;
108}
109
110// Ignore any existing FuncUnwinders for this function, create a new one and don't add it to the
111// UnwindTable.  This is intended for use by target modules show-unwind where we want to create
112// new UnwindPlans, not re-use existing ones.
113
114FuncUnwindersSP
115UnwindTable::GetUncachedFuncUnwindersContainingAddress (const Address& addr, SymbolContext &sc)
116{
117    FuncUnwindersSP no_unwind_found;
118    Initialize();
119
120    AddressRange range;
121    if (!sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0, false, range) || !range.GetBaseAddress().IsValid())
122    {
123        // Does the eh_frame unwind info has a function bounds for this addr?
124        if (m_eh_frame == NULL || !m_eh_frame->GetAddressRange (addr, range))
125        {
126            return no_unwind_found;
127        }
128    }
129
130    FuncUnwindersSP func_unwinder_sp(new FuncUnwinders(*this, m_assembly_profiler, range));
131    return func_unwinder_sp;
132}
133
134
135void
136UnwindTable::Dump (Stream &s)
137{
138    s.Printf("UnwindTable for '%s':\n", m_object_file.GetFileSpec().GetPath().c_str());
139    const_iterator begin = m_unwinds.begin();
140    const_iterator end = m_unwinds.end();
141    for (const_iterator pos = begin; pos != end; ++pos)
142    {
143        s.Printf ("[%u] 0x%16.16" PRIx64 "\n", (unsigned)std::distance (begin, pos), pos->first);
144    }
145    s.EOL();
146}
147
148DWARFCallFrameInfo *
149UnwindTable::GetEHFrameInfo ()
150{
151    Initialize();
152    return m_eh_frame;
153}
154