1 //===-- SectionLoadList.cpp -----------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "lldb/Target/SectionLoadList.h"
10 
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/Section.h"
13 #include "lldb/Symbol/Block.h"
14 #include "lldb/Symbol/Symbol.h"
15 #include "lldb/Symbol/SymbolContext.h"
16 #include "lldb/Utility/LLDBLog.h"
17 #include "lldb/Utility/Log.h"
18 #include "lldb/Utility/Stream.h"
19 
20 using namespace lldb;
21 using namespace lldb_private;
22 
23 SectionLoadList::SectionLoadList(const SectionLoadList &rhs)
24     : m_addr_to_sect(), m_sect_to_addr(), m_mutex() {
25   std::lock_guard<std::recursive_mutex> guard(rhs.m_mutex);
26   m_addr_to_sect = rhs.m_addr_to_sect;
27   m_sect_to_addr = rhs.m_sect_to_addr;
28 }
29 
30 void SectionLoadList::operator=(const SectionLoadList &rhs) {
31   std::lock(m_mutex, rhs.m_mutex);
32   std::lock_guard<std::recursive_mutex> lhs_guard(m_mutex, std::adopt_lock);
33   std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_mutex, std::adopt_lock);
34   m_addr_to_sect = rhs.m_addr_to_sect;
35   m_sect_to_addr = rhs.m_sect_to_addr;
36 }
37 
38 bool SectionLoadList::IsEmpty() const {
39   std::lock_guard<std::recursive_mutex> guard(m_mutex);
40   return m_addr_to_sect.empty();
41 }
42 
43 void SectionLoadList::Clear() {
44   std::lock_guard<std::recursive_mutex> guard(m_mutex);
45   m_addr_to_sect.clear();
46   m_sect_to_addr.clear();
47 }
48 
49 addr_t
50 SectionLoadList::GetSectionLoadAddress(const lldb::SectionSP &section) const {
51   // TODO: add support for the same section having multiple load addresses
52   addr_t section_load_addr = LLDB_INVALID_ADDRESS;
53   if (section) {
54     std::lock_guard<std::recursive_mutex> guard(m_mutex);
55     sect_to_addr_collection::const_iterator pos =
56         m_sect_to_addr.find(section.get());
57 
58     if (pos != m_sect_to_addr.end())
59       section_load_addr = pos->second;
60   }
61   return section_load_addr;
62 }
63 
64 bool SectionLoadList::SetSectionLoadAddress(const lldb::SectionSP &section,
65                                             addr_t load_addr,
66                                             bool warn_multiple) {
67   Log *log = GetLog(LLDBLog::DynamicLoader);
68   ModuleSP module_sp(section->GetModule());
69 
70   if (module_sp) {
71     LLDB_LOGV(log, "(section = {0} ({1}.{2}), load_addr = {3:x}) module = {4}",
72               section.get(), module_sp->GetFileSpec(), section->GetName(),
73               load_addr, module_sp.get());
74 
75     if (section->GetByteSize() == 0)
76       return false; // No change
77 
78     // Fill in the section -> load_addr map
79     std::lock_guard<std::recursive_mutex> guard(m_mutex);
80     sect_to_addr_collection::iterator sta_pos =
81         m_sect_to_addr.find(section.get());
82     if (sta_pos != m_sect_to_addr.end()) {
83       if (load_addr == sta_pos->second)
84         return false; // No change...
85       else
86         sta_pos->second = load_addr;
87     } else
88       m_sect_to_addr[section.get()] = load_addr;
89 
90     // Fill in the load_addr -> section map
91     addr_to_sect_collection::iterator ats_pos = m_addr_to_sect.find(load_addr);
92     if (ats_pos != m_addr_to_sect.end()) {
93       // Some sections are ok to overlap, and for others we should warn. When
94       // we have multiple load addresses that correspond to a section, we will
95       // always attribute the section to the be last section that claims it
96       // exists at that address. Sometimes it is ok for more that one section
97       // to be loaded at a specific load address, and other times it isn't. The
98       // "warn_multiple" parameter tells us if we should warn in this case or
99       // not. The DynamicLoader plug-in subclasses should know which sections
100       // should warn and which shouldn't (darwin shared cache modules all
101       // shared the same "__LINKEDIT" sections, so the dynamic loader can pass
102       // false for "warn_multiple").
103       if (warn_multiple && section != ats_pos->second) {
104         ModuleSP module_sp(section->GetModule());
105         if (module_sp) {
106           ModuleSP curr_module_sp(ats_pos->second->GetModule());
107           if (curr_module_sp) {
108             module_sp->ReportWarning(
109                 "address {0:x16} maps to more than one section: {1}.{2} and "
110                 "{3}.{4}",
111                 load_addr, module_sp->GetFileSpec().GetFilename().GetCString(),
112                 section->GetName().GetCString(),
113                 curr_module_sp->GetFileSpec().GetFilename().GetCString(),
114                 ats_pos->second->GetName().GetCString());
115           }
116         }
117       }
118       ats_pos->second = section;
119     } else {
120       // Remove the old address->section entry, if
121       // there is one.
122       for (const auto &entry : m_addr_to_sect) {
123         if (entry.second == section) {
124           const auto &it_pos = m_addr_to_sect.find(entry.first);
125           m_addr_to_sect.erase(it_pos);
126           break;
127         }
128       }
129       m_addr_to_sect[load_addr] = section;
130     }
131     return true; // Changed
132 
133   } else {
134     if (log) {
135       LLDB_LOGF(
136           log,
137           "SectionLoadList::%s (section = %p (%s), load_addr = 0x%16.16" PRIx64
138           ") error: module has been deleted",
139           __FUNCTION__, static_cast<void *>(section.get()),
140           section->GetName().AsCString(), load_addr);
141     }
142   }
143   return false;
144 }
145 
146 size_t SectionLoadList::SetSectionUnloaded(const lldb::SectionSP &section_sp) {
147   size_t unload_count = 0;
148 
149   if (section_sp) {
150     Log *log = GetLog(LLDBLog::DynamicLoader);
151 
152     if (log && log->GetVerbose()) {
153       ModuleSP module_sp = section_sp->GetModule();
154       std::string module_name("<Unknown>");
155       if (module_sp) {
156         const FileSpec &module_file_spec(
157             section_sp->GetModule()->GetFileSpec());
158         module_name = module_file_spec.GetPath();
159       }
160       LLDB_LOGF(log, "SectionLoadList::%s (section = %p (%s.%s))", __FUNCTION__,
161                 static_cast<void *>(section_sp.get()), module_name.c_str(),
162                 section_sp->GetName().AsCString());
163     }
164 
165     std::lock_guard<std::recursive_mutex> guard(m_mutex);
166 
167     sect_to_addr_collection::iterator sta_pos =
168         m_sect_to_addr.find(section_sp.get());
169     if (sta_pos != m_sect_to_addr.end()) {
170       ++unload_count;
171       addr_t load_addr = sta_pos->second;
172       m_sect_to_addr.erase(sta_pos);
173 
174       addr_to_sect_collection::iterator ats_pos =
175           m_addr_to_sect.find(load_addr);
176       if (ats_pos != m_addr_to_sect.end())
177         m_addr_to_sect.erase(ats_pos);
178     }
179   }
180   return unload_count;
181 }
182 
183 bool SectionLoadList::SetSectionUnloaded(const lldb::SectionSP &section_sp,
184                                          addr_t load_addr) {
185   Log *log = GetLog(LLDBLog::DynamicLoader);
186 
187   if (log && log->GetVerbose()) {
188     ModuleSP module_sp = section_sp->GetModule();
189     std::string module_name("<Unknown>");
190     if (module_sp) {
191       const FileSpec &module_file_spec(section_sp->GetModule()->GetFileSpec());
192       module_name = module_file_spec.GetPath();
193     }
194     LLDB_LOGF(
195         log,
196         "SectionLoadList::%s (section = %p (%s.%s), load_addr = 0x%16.16" PRIx64
197         ")",
198         __FUNCTION__, static_cast<void *>(section_sp.get()),
199         module_name.c_str(), section_sp->GetName().AsCString(), load_addr);
200   }
201   bool erased = false;
202   std::lock_guard<std::recursive_mutex> guard(m_mutex);
203   sect_to_addr_collection::iterator sta_pos =
204       m_sect_to_addr.find(section_sp.get());
205   if (sta_pos != m_sect_to_addr.end()) {
206     erased = true;
207     m_sect_to_addr.erase(sta_pos);
208   }
209 
210   addr_to_sect_collection::iterator ats_pos = m_addr_to_sect.find(load_addr);
211   if (ats_pos != m_addr_to_sect.end()) {
212     erased = true;
213     m_addr_to_sect.erase(ats_pos);
214   }
215 
216   return erased;
217 }
218 
219 bool SectionLoadList::ResolveLoadAddress(addr_t load_addr, Address &so_addr,
220                                          bool allow_section_end) const {
221   // First find the top level section that this load address exists in
222   std::lock_guard<std::recursive_mutex> guard(m_mutex);
223   if (!m_addr_to_sect.empty()) {
224     addr_to_sect_collection::const_iterator pos =
225         m_addr_to_sect.lower_bound(load_addr);
226     if (pos != m_addr_to_sect.end()) {
227       if (load_addr != pos->first && pos != m_addr_to_sect.begin())
228         --pos;
229       const addr_t pos_load_addr = pos->first;
230       if (load_addr >= pos_load_addr) {
231         addr_t offset = load_addr - pos_load_addr;
232         if (offset < pos->second->GetByteSize() + (allow_section_end ? 1 : 0)) {
233           // We have found the top level section, now we need to find the
234           // deepest child section.
235           return pos->second->ResolveContainedAddress(offset, so_addr,
236                                                       allow_section_end);
237         }
238       }
239     } else {
240       // There are no entries that have an address that is >= load_addr, so we
241       // need to check the last entry on our collection.
242       addr_to_sect_collection::const_reverse_iterator rpos =
243           m_addr_to_sect.rbegin();
244       if (load_addr >= rpos->first) {
245         addr_t offset = load_addr - rpos->first;
246         if (offset <
247             rpos->second->GetByteSize() + (allow_section_end ? 1 : 0)) {
248           // We have found the top level section, now we need to find the
249           // deepest child section.
250           return rpos->second->ResolveContainedAddress(offset, so_addr,
251                                                        allow_section_end);
252         }
253       }
254     }
255   }
256   so_addr.Clear();
257   return false;
258 }
259 
260 void SectionLoadList::Dump(Stream &s, Target *target) {
261   std::lock_guard<std::recursive_mutex> guard(m_mutex);
262   addr_to_sect_collection::const_iterator pos, end;
263   for (pos = m_addr_to_sect.begin(), end = m_addr_to_sect.end(); pos != end;
264        ++pos) {
265     s.Printf("addr = 0x%16.16" PRIx64 ", section = %p: ", pos->first,
266              static_cast<void *>(pos->second.get()));
267     pos->second->Dump(s.AsRawOstream(), s.GetIndentLevel(), target, 0);
268   }
269 }
270