SymbolFile/DWARF/DWARFDebugInfo.cpp

//===-- DWARFDebugInfo.cpp --------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "SymbolFileDWARF.h"

#include <algorithm>
#include <set>

#include "lldb/Host/PosixApi.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Utility/RegularExpression.h"
#include "lldb/Utility/Stream.h"

#include "DWARFCompileUnit.h"
#include "DWARFDebugAranges.h"
#include "DWARFDebugAranges.h"
#include "DWARFDebugInfo.h"
#include "DWARFDebugInfoEntry.h"
#include "DWARFFormValue.h"
#include "LogChannelDWARF.h"

using namespace lldb;
using namespace lldb_private;
using namespace std;

//----------------------------------------------------------------------
// Constructor
//----------------------------------------------------------------------
DWARFDebugInfo::DWARFDebugInfo()
    : m_dwarf2Data(NULL), m_compile_units(), m_cu_aranges_ap() {}

//----------------------------------------------------------------------
// SetDwarfData
//----------------------------------------------------------------------
void DWARFDebugInfo::SetDwarfData(SymbolFileDWARF *dwarf2Data) {
  m_dwarf2Data = dwarf2Data;
  m_compile_units.clear();
}

DWARFDebugAranges &DWARFDebugInfo::GetCompileUnitAranges() {
  if (m_cu_aranges_ap.get() == NULL && m_dwarf2Data) {
    Log *log(LogChannelDWARF::GetLogIfAll(DWARF_LOG_DEBUG_ARANGES));

    m_cu_aranges_ap.reset(new DWARFDebugAranges());
    const DWARFDataExtractor &debug_aranges_data =
        m_dwarf2Data->get_debug_aranges_data();
    if (debug_aranges_data.GetByteSize() > 0) {
      if (log)
        log->Printf(
            "DWARFDebugInfo::GetCompileUnitAranges() for \"%s\" from "
            ".debug_aranges",
            m_dwarf2Data->GetObjectFile()->GetFileSpec().GetPath().c_str());
      m_cu_aranges_ap->Extract(debug_aranges_data);
    }

    // Make a list of all CUs represented by the arange data in the file.
    std::set<dw_offset_t> cus_with_data;
    for (size_t n = 0; n < m_cu_aranges_ap.get()->GetNumRanges(); n++) {
      dw_offset_t offset = m_cu_aranges_ap.get()->OffsetAtIndex(n);
      if (offset != DW_INVALID_OFFSET)
        cus_with_data.insert(offset);
    }

    // Manually build arange data for everything that wasn't in the
    // .debug_aranges table.
    bool printed = false;
    const size_t num_compile_units = GetNumCompileUnits();
    for (size_t idx = 0; idx < num_compile_units; ++idx) {
      DWARFCompileUnit *cu = GetCompileUnitAtIndex(idx);

      dw_offset_t offset = cu->GetOffset();
      if (cus_with_data.find(offset) == cus_with_data.end()) {
        if (log) {
          if (!printed)
            log->Printf(
                "DWARFDebugInfo::GetCompileUnitAranges() for \"%s\" by parsing",
                m_dwarf2Data->GetObjectFile()->GetFileSpec().GetPath().c_str());
          printed = true;
        }
        cu->BuildAddressRangeTable(m_dwarf2Data, m_cu_aranges_ap.get());
      }
    }

    const bool minimize = true;
    m_cu_aranges_ap->Sort(minimize);
  }
  return *m_cu_aranges_ap.get();
}

void DWARFDebugInfo::ParseCompileUnitHeadersIfNeeded() {
  if (m_compile_units.empty()) {
    if (m_dwarf2Data != NULL) {
      lldb::offset_t offset = 0;
      const DWARFDataExtractor &debug_info_data =
          m_dwarf2Data->get_debug_info_data();
      while (debug_info_data.ValidOffset(offset)) {
        DWARFCompileUnitSP cu_sp(new DWARFCompileUnit(m_dwarf2Data));
        // Out of memory?
        if (cu_sp.get() == NULL)
          break;

        if (cu_sp->Extract(debug_info_data, &offset) == false)
          break;

        m_compile_units.push_back(cu_sp);

        offset = cu_sp->GetNextCompileUnitOffset();
      }
    }
  }
}

size_t DWARFDebugInfo::GetNumCompileUnits() {
  ParseCompileUnitHeadersIfNeeded();
  return m_compile_units.size();
}

DWARFCompileUnit *DWARFDebugInfo::GetCompileUnitAtIndex(uint32_t idx) {
  DWARFCompileUnit *cu = NULL;
  if (idx < GetNumCompileUnits())
    cu = m_compile_units[idx].get();
  return cu;
}

bool DWARFDebugInfo::ContainsCompileUnit(const DWARFCompileUnit *cu) const {
  // Not a verify efficient function, but it is handy for use in assertions
  // to make sure that a compile unit comes from a debug information file.
  CompileUnitColl::const_iterator end_pos = m_compile_units.end();
  CompileUnitColl::const_iterator pos;

  for (pos = m_compile_units.begin(); pos != end_pos; ++pos) {
    if (pos->get() == cu)
      return true;
  }
  return false;
}

bool DWARFDebugInfo::OffsetLessThanCompileUnitOffset(
    dw_offset_t offset, const DWARFCompileUnitSP &cu_sp) {
  return offset < cu_sp->GetOffset();
}

DWARFCompileUnit *DWARFDebugInfo::GetCompileUnit(dw_offset_t cu_offset,
                                                 uint32_t *idx_ptr) {
  DWARFCompileUnitSP cu_sp;
  uint32_t cu_idx = DW_INVALID_INDEX;
  if (cu_offset != DW_INVALID_OFFSET) {
    ParseCompileUnitHeadersIfNeeded();

    // Watch out for single compile unit executable as they are pretty common
    const size_t num_cus = m_compile_units.size();
    if (num_cus == 1) {
      if (m_compile_units[0]->GetOffset() == cu_offset) {
        cu_sp = m_compile_units[0];
        cu_idx = 0;
      }
    } else if (num_cus) {
      CompileUnitColl::const_iterator end_pos = m_compile_units.end();
      CompileUnitColl::const_iterator begin_pos = m_compile_units.begin();
      CompileUnitColl::const_iterator pos = std::upper_bound(
          begin_pos, end_pos, cu_offset, OffsetLessThanCompileUnitOffset);
      if (pos != begin_pos) {
        --pos;
        if ((*pos)->GetOffset() == cu_offset) {
          cu_sp = *pos;
          cu_idx = std::distance(begin_pos, pos);
        }
      }
    }
  }
  if (idx_ptr)
    *idx_ptr = cu_idx;
  return cu_sp.get();
}

DWARFCompileUnit *DWARFDebugInfo::GetCompileUnit(const DIERef &die_ref) {
  if (die_ref.cu_offset == DW_INVALID_OFFSET)
    return GetCompileUnitContainingDIEOffset(die_ref.die_offset);
  else
    return GetCompileUnit(die_ref.cu_offset);
}

DWARFCompileUnit *
DWARFDebugInfo::GetCompileUnitContainingDIEOffset(dw_offset_t die_offset) {
  ParseCompileUnitHeadersIfNeeded();

  DWARFCompileUnitSP cu_sp;

  // Watch out for single compile unit executable as they are pretty common
  const size_t num_cus = m_compile_units.size();
  if (num_cus == 1) {
    if (m_compile_units[0]->ContainsDIEOffset(die_offset))
      return m_compile_units[0].get();
  } else if (num_cus) {
    CompileUnitColl::const_iterator end_pos = m_compile_units.end();
    CompileUnitColl::const_iterator begin_pos = m_compile_units.begin();
    CompileUnitColl::const_iterator pos = std::upper_bound(
        begin_pos, end_pos, die_offset, OffsetLessThanCompileUnitOffset);
    if (pos != begin_pos) {
      --pos;
      if ((*pos)->ContainsDIEOffset(die_offset))
        return (*pos).get();
    }
  }

  return nullptr;
}

DWARFDIE
DWARFDebugInfo::GetDIEForDIEOffset(dw_offset_t die_offset) {
  DWARFCompileUnit *cu = GetCompileUnitContainingDIEOffset(die_offset);
  if (cu)
    return cu->GetDIE(die_offset);
  return DWARFDIE();
}

//----------------------------------------------------------------------
// GetDIE()
//
// Get the DIE (Debug Information Entry) with the specified offset.
//----------------------------------------------------------------------
DWARFDIE
DWARFDebugInfo::GetDIE(const DIERef &die_ref) {
  DWARFCompileUnit *cu = GetCompileUnit(die_ref);
  if (cu)
    return cu->GetDIE(die_ref.die_offset);
  return DWARFDIE(); // Not found
}

//----------------------------------------------------------------------
// Parse
//
// Parses the .debug_info section and uses the .debug_abbrev section
// and various other sections in the SymbolFileDWARF class and calls the
// supplied callback function each time a compile unit header, or debug
// information entry is successfully parsed. This function can be used
// for different tasks such as parsing the file contents into a
// structured data, dumping, verifying and much more.
//----------------------------------------------------------------------
void DWARFDebugInfo::Parse(SymbolFileDWARF *dwarf2Data, Callback callback,
                           void *userData) {
  if (dwarf2Data) {
    lldb::offset_t offset = 0;
    uint32_t depth = 0;
    DWARFCompileUnitSP cu(new DWARFCompileUnit(dwarf2Data));
    if (cu.get() == NULL)
      return;
    DWARFDebugInfoEntry die;

    while (cu->Extract(dwarf2Data->get_debug_info_data(), &offset)) {
      const dw_offset_t next_cu_offset = cu->GetNextCompileUnitOffset();

      depth = 0;
      // Call the callback function with no DIE pointer for the compile unit
      // and get the offset that we are to continue to parse from
      offset = callback(dwarf2Data, cu.get(), NULL, offset, depth, userData);

      // Make sure we are within our compile unit
      if (offset < next_cu_offset) {
        // We are in our compile unit, parse starting at the offset
        // we were told to parse
        bool done = false;
        while (!done && die.Extract(dwarf2Data, cu.get(), &offset)) {
          // Call the callback function with DIE pointer that falls within the
          // compile unit
          offset =
              callback(dwarf2Data, cu.get(), &die, offset, depth, userData);

          if (die.IsNULL()) {
            if (depth)
              --depth;
            else
              done = true; // We are done with this compile unit!
          } else if (die.HasChildren())
            ++depth;
        }
      }

      // Make sure the offset returned is valid, and if not stop parsing.
      // Returning DW_INVALID_OFFSET from this callback is a good way to end
      // all parsing
      if (!dwarf2Data->get_debug_info_data().ValidOffset(offset))
        break;

      // See if during the callback anyone retained a copy of the compile
      // unit other than ourselves and if so, let whomever did own the object
      // and create a new one for our own use!
      if (!cu.unique())
        cu.reset(new DWARFCompileUnit(dwarf2Data));

      // Make sure we start on a proper
      offset = next_cu_offset;
    }
  }
}

typedef struct DumpInfo {
  DumpInfo(Stream *init_strm, uint32_t off, uint32_t depth)
      : strm(init_strm), die_offset(off), recurse_depth(depth),
        found_depth(UINT32_MAX), found_die(false), ancestors() {}
  Stream *strm;
  const uint32_t die_offset;
  const uint32_t recurse_depth;
  uint32_t found_depth;
  bool found_die;
  std::vector<DWARFDebugInfoEntry> ancestors;

  DISALLOW_COPY_AND_ASSIGN(DumpInfo);
} DumpInfo;

//----------------------------------------------------------------------
// DumpCallback
//
// A callback function for the static DWARFDebugInfo::Parse() function
// that gets called each time a compile unit header or debug information
// entry is successfully parsed.
//
// This function dump DWARF information and obey recurse depth and
// whether a single DIE is to be dumped (or all of the data).
//----------------------------------------------------------------------
static dw_offset_t DumpCallback(SymbolFileDWARF *dwarf2Data,
                                DWARFCompileUnit *cu, DWARFDebugInfoEntry *die,
                                const dw_offset_t next_offset,
                                const uint32_t curr_depth, void *userData) {
  DumpInfo *dumpInfo = (DumpInfo *)userData;
  Stream *s = dumpInfo->strm;
  bool show_parents =
      s->GetFlags().Test(DWARFDebugInfo::eDumpFlag_ShowAncestors);

  if (die) {
    // Are we dumping everything?
    if (dumpInfo->die_offset == DW_INVALID_OFFSET) {
      // Yes we are dumping everything. Obey our recurse level though
      if (curr_depth < dumpInfo->recurse_depth)
        die->Dump(dwarf2Data, cu, *s, 0);
    } else {
      // We are dumping a specific DIE entry by offset
      if (dumpInfo->die_offset == die->GetOffset()) {
        // We found the DIE we were looking for, dump it!
        if (show_parents) {
          s->SetIndentLevel(0);
          const uint32_t num_ancestors = dumpInfo->ancestors.size();
          if (num_ancestors > 0) {
            for (uint32_t i = 0; i < num_ancestors - 1; ++i) {
              dumpInfo->ancestors[i].Dump(dwarf2Data, cu, *s, 0);
              s->IndentMore();
            }
          }
        }

        dumpInfo->found_depth = curr_depth;

        die->Dump(dwarf2Data, cu, *s, 0);

        // Note that we found the DIE we were looking for
        dumpInfo->found_die = true;

        // Since we are dumping a single DIE, if there are no children we are
        // done!
        if (!die->HasChildren() || dumpInfo->recurse_depth == 0)
          return DW_INVALID_OFFSET; // Return an invalid address to end parsing
      } else if (dumpInfo->found_die) {
        // Are we done with all the children?
        if (curr_depth <= dumpInfo->found_depth)
          return DW_INVALID_OFFSET;

        // We have already found our DIE and are printing it's children. Obey
        // our recurse depth and return an invalid offset if we get done
        // dumping all of the children
        if (dumpInfo->recurse_depth == UINT32_MAX ||
            curr_depth <= dumpInfo->found_depth + dumpInfo->recurse_depth)
          die->Dump(dwarf2Data, cu, *s, 0);
      } else if (dumpInfo->die_offset > die->GetOffset()) {
        if (show_parents)
          dumpInfo->ancestors.back() = *die;
      }
    }

    // Keep up with our indent level
    if (die->IsNULL()) {
      if (show_parents)
        dumpInfo->ancestors.pop_back();

      if (curr_depth <= 1)
        return cu->GetNextCompileUnitOffset();
      else
        s->IndentLess();
    } else if (die->HasChildren()) {
      if (show_parents) {
        DWARFDebugInfoEntry null_die;
        dumpInfo->ancestors.push_back(null_die);
      }
      s->IndentMore();
    }
  } else {
    if (cu == NULL)
      s->PutCString("NULL - cu");
    // We have a compile unit, reset our indent level to zero just in case
    s->SetIndentLevel(0);

    // See if we are dumping everything?
    if (dumpInfo->die_offset == DW_INVALID_OFFSET) {
      // We are dumping everything
      if (cu) {
        cu->Dump(s);
        return cu->GetFirstDIEOffset(); // Return true to parse all DIEs in this
                                        // Compile Unit
      } else {
        return DW_INVALID_OFFSET;
      }
    } else {
      if (show_parents) {
        dumpInfo->ancestors.clear();
        dumpInfo->ancestors.resize(1);
      }

      // We are dumping only a single DIE possibly with it's children and
      // we must find it's compile unit before we can dump it properly
      if (cu && dumpInfo->die_offset < cu->GetFirstDIEOffset()) {
        // Not found, maybe the DIE offset provided wasn't correct?
        //  *ostrm_ptr << "DIE at offset " << HEX32 << dumpInfo->die_offset << "
        //  was not found." << endl;
        return DW_INVALID_OFFSET;
      } else {
        // See if the DIE is in this compile unit?
        if (cu && dumpInfo->die_offset < cu->GetNextCompileUnitOffset()) {
          return next_offset;
          //  // We found our compile unit that contains our DIE, just skip to
          //  dumping the requested DIE...
          //  return dumpInfo->die_offset;
        } else {
          // Skip to the next compile unit as the DIE isn't in the current one!
          if (cu) {
            return cu->GetNextCompileUnitOffset();
          } else {
            return DW_INVALID_OFFSET;
          }
        }
      }
    }
  }

  // Just return the current offset to parse the next CU or DIE entry
  return next_offset;
}

//----------------------------------------------------------------------
// Dump
//
// Dump the information in the .debug_info section to the specified
// ostream. If die_offset is valid, a single DIE will be dumped. If the
// die_offset is invalid, all the DWARF information will be dumped. Both
// cases will obey a "recurse_depth" or how deep to traverse into the
// children of each DIE entry. A recurse_depth of zero will dump all
// compile unit headers. A recurse_depth of 1 will dump all compile unit
// headers and the DW_TAG_compile unit tags. A depth of 2 will also
// dump all types and functions.
//----------------------------------------------------------------------
void DWARFDebugInfo::Dump(Stream *s, SymbolFileDWARF *dwarf2Data,
                          const uint32_t die_offset,
                          const uint32_t recurse_depth) {
  DumpInfo dumpInfo(s, die_offset, recurse_depth);
  s->PutCString(".debug_info contents");
  if (dwarf2Data->get_debug_info_data().GetByteSize() > 0) {
    if (die_offset == DW_INVALID_OFFSET)
      s->PutCString(":\n");
    else {
      s->Printf(" for DIE entry at .debug_info[0x%8.8x]", die_offset);
      if (recurse_depth != UINT32_MAX)
        s->Printf(" recursing %u levels deep.", recurse_depth);
      s->EOL();
    }
  } else {
    s->PutCString(": < EMPTY >\n");
    return;
  }
  DWARFDebugInfo::Parse(dwarf2Data, DumpCallback, &dumpInfo);
}

//----------------------------------------------------------------------
// Dump
//
// Dump the contents of this DWARFDebugInfo object as has been parsed
// and/or modified after it has been parsed.
//----------------------------------------------------------------------
void DWARFDebugInfo::Dump(Stream *s, const uint32_t die_offset,
                          const uint32_t recurse_depth) {
  DumpInfo dumpInfo(s, die_offset, recurse_depth);

  s->PutCString("Dumping .debug_info section from internal representation\n");

  CompileUnitColl::const_iterator pos;
  uint32_t curr_depth = 0;
  ParseCompileUnitHeadersIfNeeded();
  for (pos = m_compile_units.begin(); pos != m_compile_units.end(); ++pos) {
    DWARFCompileUnit *cu = pos->get();
    DumpCallback(m_dwarf2Data, cu, NULL, 0, curr_depth, &dumpInfo);

    const DWARFDIE die = cu->DIE();
    if (die)
      die.Dump(s, recurse_depth);
  }
}

//----------------------------------------------------------------------
// FindCallbackString
//
// A callback function for the static DWARFDebugInfo::Parse() function
// that gets called each time a compile unit header or debug information
// entry is successfully parsed.
//
// This function will find the die_offset of any items whose DW_AT_name
// matches the given string
//----------------------------------------------------------------------
typedef struct FindCallbackStringInfoTag {
  const char *name;
  bool ignore_case;
  RegularExpression *regex;
  vector<dw_offset_t> &die_offsets;
} FindCallbackStringInfo;

static dw_offset_t
FindCallbackString(SymbolFileDWARF *dwarf2Data, DWARFCompileUnit *cu,
                   DWARFDebugInfoEntry *die, const dw_offset_t next_offset,
                   const uint32_t curr_depth, void *userData) {
  FindCallbackStringInfo *info = (FindCallbackStringInfo *)userData;

  if (!die)
    return next_offset;

  const char *die_name = die->GetName(dwarf2Data, cu);
  if (!die_name)
    return next_offset;

  if (info->regex) {
    if (info->regex->Execute(llvm::StringRef(die_name)))
      info->die_offsets.push_back(die->GetOffset());
  } else {
    if ((info->ignore_case ? strcasecmp(die_name, info->name)
                           : strcmp(die_name, info->name)) == 0)
      info->die_offsets.push_back(die->GetOffset());
  }

  // Just return the current offset to parse the next CU or DIE entry
  return next_offset;
}

//----------------------------------------------------------------------
// Find
//
// Finds all DIE that have a specific DW_AT_name attribute by manually
// searching through the debug information (not using the
// .debug_pubnames section). The string must match the entire name
// and case sensitive searches are an option.
//----------------------------------------------------------------------
bool DWARFDebugInfo::Find(const char *name, bool ignore_case,
                          vector<dw_offset_t> &die_offsets) const {
  die_offsets.clear();
  if (name && name[0]) {
    FindCallbackStringInfo info = {name, ignore_case, NULL, die_offsets};
    DWARFDebugInfo::Parse(m_dwarf2Data, FindCallbackString, &info);
  }
  return !die_offsets.empty();
}

//----------------------------------------------------------------------
// Find
//
// Finds all DIE that have a specific DW_AT_name attribute by manually
// searching through the debug information (not using the
// .debug_pubnames section). The string must match the supplied regular
// expression.
//----------------------------------------------------------------------
bool DWARFDebugInfo::Find(RegularExpression &re,
                          vector<dw_offset_t> &die_offsets) const {
  die_offsets.clear();
  FindCallbackStringInfo info = {NULL, false, &re, die_offsets};
  DWARFDebugInfo::Parse(m_dwarf2Data, FindCallbackString, &info);
  return !die_offsets.empty();
}