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Shrink-to-fit our std::vector<DWARFDebugInfoEntry> collections and save 20% 

to 30% of memory. The size doubling was killing us and we ended up with up to
just under 50% of empty capacity. Cleaning this up saves us a ton of memory.

llvm-svn: 145086
This commit is contained in:
Greg Clayton 2011-11-22 21:35:27 +00:00
parent 01575f86aa
commit 1959df2c9c
3 changed files with 16 additions and 8 deletions
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10
lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.cpp
View File

@ -271,7 +271,17 @@ DWARFCompileUnit::ExtractDIEsIfNeeded (bool cu_die_only)
}
fprintf (stderr, "warning: DWARF compile unit extends beyond its bounds cu 0x%8.8x at 0x%8.8x in '%s'\n", GetOffset(), offset, path);
}
// Since std::vector objects will double their size, we really need to
// make a new array with the perfect size so we don't end up wasting
// space. So here we copy and swap to make sure we don't have any extra
// memory taken up.
if (m_die_array.size () < m_die_array.capacity())
{
DWARFDebugInfoEntry::collection exact_size_die_array (m_die_array.begin(), m_die_array.end());
exact_size_die_array.swap (m_die_array);
}
LogSP log (LogChannelDWARF::GetLogIfAll (DWARF_LOG_DEBUG_INFO));
if (log)
{

10
lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.h
View File

@ -74,13 +74,11 @@ public:
}
void
AddDIE(DWARFDebugInfoEntry& die)
AddDIE (DWARFDebugInfoEntry& die)
{
// The average bytes per DIE entry has been seen to be
// around 14-20 so lets pre-reserve the needed memory for
// our DIE entries accordingly. Search forward for "Compute
// average bytes per DIE" to see #if'ed out code that does
// that determination.
// around 14-20 so lets pre-reserve half of that since
// we are now stripping the NULL tags.
// Only reserve the memory if we are adding children of
// the main compile unit DIE. The compile unit DIE is always
@ -88,7 +86,7 @@ public:
// the first compile unit child DIE and should reserve
// the memory.
if (m_die_array.empty())
m_die_array.reserve(GetDebugInfoSize() / 14);
m_die_array.reserve(GetDebugInfoSize() / 24);
m_die_array.push_back(die);
}

4
lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
View File

@ -1926,8 +1926,8 @@ DWARFDebugInfoEntry::DumpDIECollection (Stream &strm, DWARFDebugInfoEntry::colle
{
DWARFDebugInfoEntry::const_iterator pos;
DWARFDebugInfoEntry::const_iterator end = die_collection.end();
puts("offset parent sibling child");
puts("-------- -------- -------- --------");
strm.PutCString("\noffset parent sibling child\n");
strm.PutCString("-------- -------- -------- --------\n");
for (pos = die_collection.begin(); pos != end; ++pos)
{
const DWARFDebugInfoEntry& die_ref = *pos;