lldb/source/Target/SectionLoadList.cpp

//===-- SectionLoadList.cpp -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "lldb/Target/SectionLoadList.h"

#include "lldb/Core/Module.h"
#include "lldb/Core/Section.h"
#include "lldb/Symbol/Block.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/Stream.h"

using namespace lldb;
using namespace lldb_private;

SectionLoadList::SectionLoadList(const SectionLoadList &rhs)
    : m_addr_to_sect(), m_sect_to_addr(), m_mutex() {
  std::lock_guard<std::recursive_mutex> guard(rhs.m_mutex);
  m_addr_to_sect = rhs.m_addr_to_sect;
  m_sect_to_addr = rhs.m_sect_to_addr;
}

void SectionLoadList::operator=(const SectionLoadList &rhs) {
  std::lock(m_mutex, rhs.m_mutex);
  std::lock_guard<std::recursive_mutex> lhs_guard(m_mutex, std::adopt_lock);
  std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_mutex, std::adopt_lock);
  m_addr_to_sect = rhs.m_addr_to_sect;
  m_sect_to_addr = rhs.m_sect_to_addr;
}

bool SectionLoadList::IsEmpty() const {
  std::lock_guard<std::recursive_mutex> guard(m_mutex);
  return m_addr_to_sect.empty();
}

void SectionLoadList::Clear() {
  std::lock_guard<std::recursive_mutex> guard(m_mutex);
  m_addr_to_sect.clear();
  m_sect_to_addr.clear();
}

addr_t
SectionLoadList::GetSectionLoadAddress(const lldb::SectionSP &section) const {
  // TODO: add support for the same section having multiple load addresses
  addr_t section_load_addr = LLDB_INVALID_ADDRESS;
  if (section) {
    std::lock_guard<std::recursive_mutex> guard(m_mutex);
    sect_to_addr_collection::const_iterator pos =
        m_sect_to_addr.find(section.get());

    if (pos != m_sect_to_addr.end())
      section_load_addr = pos->second;
  }
  return section_load_addr;
}

bool SectionLoadList::SetSectionLoadAddress(const lldb::SectionSP &section,
                                            addr_t load_addr,
                                            bool warn_multiple) {
  Log *log = GetLog(LLDBLog::DynamicLoader);
  ModuleSP module_sp = section->GetModule();

  if (!module_sp) {
    LLDB_LOG(log,
             "SectionLoadList::{0} (section = {1} ({2}), load_addr = {3:x}) "
             "error: module has been deleted",
             __FUNCTION__, static_cast<void *>(section.get()),
             section->GetName(), load_addr);
    return false;
  }

  LLDB_LOG_VERBOSE(log,
                   "(section = {0} ({1}.{2}), load_addr = {3:x}) module = {4}",
                   section.get(), module_sp->GetFileSpec(), section->GetName(),
                   load_addr, module_sp.get());

  if (section->GetByteSize() == 0)
    return false;

  // Fill in the section -> load_addr map.
  std::lock_guard<std::recursive_mutex> guard(m_mutex);
  sect_to_addr_collection::iterator sta_pos =
      m_sect_to_addr.find(section.get());
  addr_t old_load_addr = LLDB_INVALID_ADDRESS;

  if (sta_pos != m_sect_to_addr.end()) {
    if (load_addr == sta_pos->second)
      return false;
    old_load_addr = sta_pos->second;
    sta_pos->second = load_addr;
  } else {
    m_sect_to_addr.insert({section.get(), load_addr});
  }

  // Fill in the load_addr -> section map.
  addr_to_sect_collection::iterator ats_pos = m_addr_to_sect.find(load_addr);
  if (ats_pos != m_addr_to_sect.end()) {
    // Some sections are ok to overlap, and for others we should warn. When
    // we have multiple load addresses that correspond to a section, we will
    // always attribute the section to the be last section that claims it
    // exists at that address. Sometimes it is ok for more that one section
    // to be loaded at a specific load address, and other times it isn't. The
    // "warn_multiple" parameter tells us if we should warn in this case or
    // not. The DynamicLoader plug-in subclasses should know which sections
    // should warn and which shouldn't (darwin shared cache modules all
    // shared the same "__LINKEDIT" sections, so the dynamic loader can pass
    // false for "warn_multiple").
    if (warn_multiple && section != ats_pos->second) {
      if (ModuleSP curr_module_sp = ats_pos->second->GetModule()) {
        module_sp->ReportWarning(
            "address {0:x16} maps to more than one section: {1}.{2} and "
            "{3}.{4}",
            load_addr, module_sp->GetFileSpec().GetFilename(),
            section->GetName(), curr_module_sp->GetFileSpec().GetFilename(),
            ats_pos->second->GetName());
      }
    }
    ats_pos->second = section;
  } else {
    m_addr_to_sect.insert({load_addr, section});
  }

  // Remove the old address->section entry if there was one.
  if (old_load_addr != LLDB_INVALID_ADDRESS && old_load_addr != load_addr)
    m_addr_to_sect.erase(old_load_addr);

  return true;
}

size_t SectionLoadList::SetSectionUnloaded(const lldb::SectionSP &section_sp) {
  size_t unload_count = 0;

  if (section_sp) {
    Log *log = GetLog(LLDBLog::DynamicLoader);

    if (log && log->GetVerbose()) {
      ModuleSP module_sp = section_sp->GetModule();
      std::string module_name("<Unknown>");
      if (module_sp) {
        const FileSpec &module_file_spec(
            section_sp->GetModule()->GetFileSpec());
        module_name = module_file_spec.GetPath();
      }
      LLDB_LOG(log, "SectionLoadList::{0} (section = {1} ({2}.{3}))",
               __FUNCTION__, static_cast<void *>(section_sp.get()), module_name,
               section_sp->GetName());
    }

    std::lock_guard<std::recursive_mutex> guard(m_mutex);

    sect_to_addr_collection::iterator sta_pos =
        m_sect_to_addr.find(section_sp.get());
    if (sta_pos != m_sect_to_addr.end()) {
      ++unload_count;
      addr_t load_addr = sta_pos->second;
      m_sect_to_addr.erase(sta_pos);

      addr_to_sect_collection::iterator ats_pos =
          m_addr_to_sect.find(load_addr);
      if (ats_pos != m_addr_to_sect.end())
        m_addr_to_sect.erase(ats_pos);
    }
  }
  return unload_count;
}

bool SectionLoadList::SetSectionUnloaded(const lldb::SectionSP &section_sp,
                                         addr_t load_addr) {
  Log *log = GetLog(LLDBLog::DynamicLoader);

  if (log && log->GetVerbose()) {
    ModuleSP module_sp = section_sp->GetModule();
    std::string module_name("<Unknown>");
    if (module_sp) {
      const FileSpec &module_file_spec(section_sp->GetModule()->GetFileSpec());
      module_name = module_file_spec.GetPath();
    }
    LLDB_LOG(log,
             "SectionLoadList::{0} (section = {1:x} ({2}.{3}), load_addr = "
             "{4:x16})",
             __FUNCTION__, static_cast<void *>(section_sp.get()),
             module_name.c_str(), section_sp->GetName(), load_addr);
  }
  bool erased = false;
  std::lock_guard<std::recursive_mutex> guard(m_mutex);
  sect_to_addr_collection::iterator sta_pos =
      m_sect_to_addr.find(section_sp.get());
  if (sta_pos != m_sect_to_addr.end()) {
    erased = true;
    m_sect_to_addr.erase(sta_pos);
  }

  addr_to_sect_collection::iterator ats_pos = m_addr_to_sect.find(load_addr);
  if (ats_pos != m_addr_to_sect.end()) {
    erased = true;
    m_addr_to_sect.erase(ats_pos);
  }

  return erased;
}

bool SectionLoadList::ResolveLoadAddress(addr_t load_addr, Address &so_addr,
                                         bool allow_section_end) const {
  // First find the top level section that this load address exists in
  std::lock_guard<std::recursive_mutex> guard(m_mutex);
  if (!m_addr_to_sect.empty()) {
    addr_to_sect_collection::const_iterator pos =
        m_addr_to_sect.lower_bound(load_addr);
    if (pos != m_addr_to_sect.end()) {
      if (load_addr != pos->first && pos != m_addr_to_sect.begin())
        --pos;
      const addr_t pos_load_addr = pos->first;
      if (load_addr >= pos_load_addr) {
        addr_t offset = load_addr - pos_load_addr;
        if (offset < pos->second->GetByteSize() + (allow_section_end ? 1 : 0)) {
          // We have found the top level section, now we need to find the
          // deepest child section.
          return pos->second->ResolveContainedAddress(offset, so_addr,
                                                      allow_section_end);
        }
      }
    } else {
      // There are no entries that have an address that is >= load_addr, so we
      // need to check the last entry on our collection.
      addr_to_sect_collection::const_reverse_iterator rpos =
          m_addr_to_sect.rbegin();
      if (load_addr >= rpos->first) {
        addr_t offset = load_addr - rpos->first;
        if (offset <
            rpos->second->GetByteSize() + (allow_section_end ? 1 : 0)) {
          // We have found the top level section, now we need to find the
          // deepest child section.
          return rpos->second->ResolveContainedAddress(offset, so_addr,
                                                       allow_section_end);
        }
      }
    }
  }
  so_addr.Clear();
  return false;
}

void SectionLoadList::Dump(Stream &s, Target *target) {
  std::lock_guard<std::recursive_mutex> guard(m_mutex);
  addr_to_sect_collection::const_iterator pos, end;
  for (pos = m_addr_to_sect.begin(), end = m_addr_to_sect.end(); pos != end;
       ++pos) {
    s.Printf("addr = 0x%16.16" PRIx64 ", section = %p: ", pos->first,
             static_cast<void *>(pos->second.get()));
    pos->second->Dump(s.AsRawOstream(), s.GetIndentLevel(), target, 0);
  }
}