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<rdar://problem/13748253>

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Combine N_GSYM stab entries with their non-stab counterpart (data symbols) to make the symbol table smaller with less duplicate named symbols.

llvm-svn: 181841
This commit is contained in:
Greg Clayton
2013-05-14 22:19:37 +00:00
parent bc8d23956c
commit dacc4a953d
1 changed files with 144 additions and 94 deletions
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238
lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
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@@ -1712,8 +1712,10 @@ ObjectFileMachO::ParseSymtab (bool minimize)
std::vector<uint32_t> N_COMM_indexes;
typedef std::map <uint64_t, uint32_t> ValueToSymbolIndexMap;
typedef std::map <uint32_t, uint32_t> NListIndexToSymbolIndexMap;
typedef std::map <const char *, uint32_t> ConstNameToSymbolIndexMap;
ValueToSymbolIndexMap N_FUN_addr_to_sym_idx;
ValueToSymbolIndexMap N_STSYM_addr_to_sym_idx;
ConstNameToSymbolIndexMap N_GSYM_name_to_sym_idx;
// Any symbols that get merged into another will get an entry
// in this map so we know
NListIndexToSymbolIndexMap m_nlist_idx_to_sym_idx;
@@ -1970,6 +1972,7 @@ ObjectFileMachO::ParseSymtab (bool minimize)
bool add_nlist = true;
bool is_debug = ((nlist.n_type & NlistMaskStab) != 0);
bool demangled_is_synthesized = false;
bool is_gsym = false;
assert (sym_idx < num_syms);
@@ -1997,6 +2000,7 @@ ObjectFileMachO::ParseSymtab (bool minimize)
add_nlist = false;
else
{
is_gsym = true;
sym[sym_idx].SetExternal(true);
if (nlist.n_value != 0)
symbol_section = section_info.GetSection (nlist.n_sect, nlist.n_value);
@@ -2510,53 +2514,10 @@ ObjectFileMachO::ParseSymtab (bool minimize)
if (symbol_name)
{
sym[sym_idx].GetMangled().SetValue(ConstString(symbol_name), symbol_name_is_mangled);
}
}
if (is_debug == false)
{
if (type == eSymbolTypeCode)
{
// See if we can find a N_FUN entry for any code symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the function symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_FUN_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_FUN_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_FUN flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
}
else if (type == eSymbolTypeData)
{
// See if we can find a N_STSYM entry for any data symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the Static symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_STSYM_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_STSYM_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_STSYM flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
ConstString const_symbol_name(symbol_name);
if (is_gsym)
N_GSYM_name_to_sym_idx[const_symbol_name.GetCString()] = sym_idx;
sym[sym_idx].GetMangled().SetValue(const_symbol_name, symbol_name_is_mangled);
}
}
if (symbol_section)
@@ -2612,6 +2573,71 @@ ObjectFileMachO::ParseSymtab (bool minimize)
symbol_value -= section_file_addr;
}
if (is_debug == false)
{
if (type == eSymbolTypeCode)
{
// See if we can find a N_FUN entry for any code symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the function symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_FUN_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_FUN_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_FUN flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
}
else if (type == eSymbolTypeData)
{
// See if we can find a N_STSYM entry for any data symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the Static symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_STSYM_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_STSYM_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_STSYM flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
else
{
// Combine N_GSYM stab entries with the non stab symbol
ConstNameToSymbolIndexMap::const_iterator pos = N_GSYM_name_to_sym_idx.find(sym[sym_idx].GetMangled().GetMangledName().GetCString());
if (pos != N_GSYM_name_to_sym_idx.end())
{
const uint32_t GSYM_sym_idx = pos->second;
m_nlist_idx_to_sym_idx[nlist_idx] = GSYM_sym_idx;
// Copy the address, because often the N_GSYM address has an invalid address of zero
// when the global is a common symbol
sym[GSYM_sym_idx].GetAddress().SetSection (symbol_section);
sym[GSYM_sym_idx].GetAddress().SetOffset (symbol_value);
// We just need the flags from the linker symbol, so put these flags
// into the N_STSYM flags to avoid duplicate symbols in the symbol table
sym[GSYM_sym_idx].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
}
}
sym[sym_idx].SetID (nlist_idx);
sym[sym_idx].SetType (type);
sym[sym_idx].GetAddress().SetSection (symbol_section);
@@ -2711,6 +2737,7 @@ ObjectFileMachO::ParseSymtab (bool minimize)
SectionSP symbol_section;
lldb::addr_t symbol_byte_size = 0;
bool add_nlist = true;
bool is_gsym = false;
bool is_debug = ((nlist.n_type & NlistMaskStab) != 0);
bool demangled_is_synthesized = false;
@@ -2740,6 +2767,7 @@ ObjectFileMachO::ParseSymtab (bool minimize)
add_nlist = false;
else
{
is_gsym = true;
sym[sym_idx].SetExternal(true);
if (nlist.n_value != 0)
symbol_section = section_info.GetSection (nlist.n_sect, nlist.n_value);
@@ -3258,53 +3286,10 @@ ObjectFileMachO::ParseSymtab (bool minimize)
if (symbol_name)
{
sym[sym_idx].GetMangled().SetValue(ConstString(symbol_name), symbol_name_is_mangled);
}
}
if (is_debug == false)
{
if (type == eSymbolTypeCode)
{
// See if we can find a N_FUN entry for any code symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the function symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_FUN_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_FUN_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_FUN flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
}
else if (type == eSymbolTypeData)
{
// See if we can find a N_STSYM entry for any data symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the Static symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_STSYM_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_STSYM_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_STSYM flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
ConstString const_symbol_name(symbol_name);
if (is_gsym)
N_GSYM_name_to_sym_idx[const_symbol_name.GetCString()] = sym_idx;
sym[sym_idx].GetMangled().SetValue(const_symbol_name, symbol_name_is_mangled);
}
}
if (symbol_section)
@@ -3355,6 +3340,71 @@ ObjectFileMachO::ParseSymtab (bool minimize)
symbol_value -= section_file_addr;
}
if (is_debug == false)
{
if (type == eSymbolTypeCode)
{
// See if we can find a N_FUN entry for any code symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the function symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_FUN_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_FUN_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_FUN flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
}
else if (type == eSymbolTypeData)
{
// See if we can find a N_STSYM entry for any data symbols.
// If we do find a match, and the name matches, then we
// can merge the two into just the Static symbol to avoid
// duplicate entries in the symbol table
ValueToSymbolIndexMap::const_iterator pos = N_STSYM_addr_to_sym_idx.find (nlist.n_value);
if (pos != N_STSYM_addr_to_sym_idx.end())
{
if ((symbol_name_is_mangled == true && sym[sym_idx].GetMangled().GetMangledName() == sym[pos->second].GetMangled().GetMangledName()) ||
(symbol_name_is_mangled == false && sym[sym_idx].GetMangled().GetDemangledName() == sym[pos->second].GetMangled().GetDemangledName()))
{
m_nlist_idx_to_sym_idx[nlist_idx] = pos->second;
// We just need the flags from the linker symbol, so put these flags
// into the N_STSYM flags to avoid duplicate symbols in the symbol table
sym[pos->second].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
else
{
// Combine N_GSYM stab entries with the non stab symbol
ConstNameToSymbolIndexMap::const_iterator pos = N_GSYM_name_to_sym_idx.find(sym[sym_idx].GetMangled().GetMangledName().GetCString());
if (pos != N_GSYM_name_to_sym_idx.end())
{
const uint32_t GSYM_sym_idx = pos->second;
m_nlist_idx_to_sym_idx[nlist_idx] = GSYM_sym_idx;
// Copy the address, because often the N_GSYM address has an invalid address of zero
// when the global is a common symbol
sym[GSYM_sym_idx].GetAddress().SetSection (symbol_section);
sym[GSYM_sym_idx].GetAddress().SetOffset (symbol_value);
// We just need the flags from the linker symbol, so put these flags
// into the N_STSYM flags to avoid duplicate symbols in the symbol table
sym[GSYM_sym_idx].SetFlags (nlist.n_type << 16 | nlist.n_desc);
sym[sym_idx].Clear();
continue;
}
}
}
}
sym[sym_idx].SetID (nlist_idx);
sym[sym_idx].SetType (type);
sym[sym_idx].GetAddress().SetSection (symbol_section);