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Improved name demangling performance by 20% on darwin. 

llvm-svn: 113032
This commit is contained in:
Greg Clayton 2010-09-03 23:26:12 +00:00
parent 207b9d6218
commit e41e58997c
5 changed files with 55 additions and 23 deletions
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6
lldb/include/lldb/Core/ConstString.h
View File

@ -290,7 +290,11 @@ public:
/// @li \b false if the contained string is not empty.
//------------------------------------------------------------------
bool
IsEmpty () const;
IsEmpty () const
{
return m_string == NULL || m_string[0] == '\0';
}
//------------------------------------------------------------------
/// Set the C string value.

1
lldb/lldb.xcodeproj/project.pbxproj
View File

@ -2295,6 +2295,7 @@
isa = PBXProject;
buildConfigurationList = 1DEB91EF08733DB70010E9CD /* Build configuration list for PBXProject "lldb" */;
compatibilityVersion = "Xcode 3.1";
developmentRegion = English;
hasScannedForEncodings = 1;
knownRegions = (
en,

9
lldb/source/Core/ConstString.cpp
View File

@ -390,15 +390,6 @@ ConstString::DumpDebug(Stream *s) const
s->Printf("%*p: ConstString, string = %s%s%s, length = %zu", (int)sizeof(void*) * 2, this, parens, cstr, parens, cstr_len);
}
//----------------------------------------------------------------------
// Returns true if the contained string is empty.
//----------------------------------------------------------------------
bool
ConstString::IsEmpty() const
{
return m_string == NULL || m_string[0] == '\0';
}
//----------------------------------------------------------------------
// Set the string value in the object by uniquing the "cstr" string
// value in our global string pool.

45
lldb/source/Core/Mangled.cpp
View File

@ -9,6 +9,8 @@
#include <cxxabi.h>
#include "llvm/ADT/DenseMap.h"
#include "lldb/Core/ConstString.h"
#include "lldb/Core/Mangled.h"
#include "lldb/Core/Stream.h"
@ -142,18 +144,47 @@ Mangled::GetDemangledName () const
const char * mangled = m_mangled.AsCString();
if (mangled[0])
{
char *demangled_name = abi::__cxa_demangle (mangled, NULL, NULL, NULL);
// Since demangling can be a costly, and since all names that go
// into a ConstString (like our m_mangled and m_demangled members)
// end up being unique "const char *" values, we can use a DenseMap
// to speed up our lookup. We do this because often our symbol table
// and our debug information both have the mangled names which they
// would each need to demangle. Also, with GCC we end up with the one
// definition rule where a lot of STL code produces symbols that are
// in multiple compile units and the mangled names end up being in
// the same binary multiple times. The performance win isn't huge,
// but we showed a 20% improvement on darwin.
typedef llvm::DenseMap<const char *, const char *> MangledToDemangledMap;
static MangledToDemangledMap g_mangled_to_demangled;
if (demangled_name)
// Check our mangled string pointer to demangled string pointer map first
MangledToDemangledMap::const_iterator pos = g_mangled_to_demangled.find (mangled);
if (pos != g_mangled_to_demangled.end())
{
m_demangled.SetCString (demangled_name);
free (demangled_name);
// We have already demangled this string, we can just use our saved result!
m_demangled.SetCString(pos->second);
}
else
{
// Set the demangled string to the empty string to indicate we
// tried to parse it once and failed.
m_demangled.SetCString("");
// We didn't already mangle this name, demangle it and if all goes well
// add it to our map.
char *demangled_name = abi::__cxa_demangle (mangled, NULL, NULL, NULL);
if (demangled_name)
{
m_demangled.SetCString (demangled_name);
// Now that the name has been uniqued, add the uniqued C string
// pointer from m_mangled as the key to the uniqued C string
// pointer in m_demangled.
g_mangled_to_demangled.insert (std::make_pair (mangled, m_demangled.GetCString()));
free (demangled_name);
}
else
{
// Set the demangled string to the empty string to indicate we
// tried to parse it once and failed.
m_demangled.SetCString("");
}
}
}
}

17
lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.cpp
View File

@ -9,6 +9,7 @@
#include "DWARFCompileUnit.h"
#include "lldb/Core/Mangled.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/Timer.h"
@ -591,7 +592,7 @@ DWARFCompileUnit::Index
DWARFDebugInfoEntry::Attributes attributes;
const char *name = NULL;
const char *mangled = NULL;
Mangled mangled;
bool is_variable = false;
bool is_declaration = false;
bool is_artificial = false;
@ -629,7 +630,7 @@ DWARFCompileUnit::Index
case DW_AT_MIPS_linkage_name:
if (attributes.ExtractFormValueAtIndex(m_dwarf2Data, i, form_value))
mangled = form_value.AsCString(debug_str);
mangled.GetMangledName().SetCString(form_value.AsCString(debug_str));
break;
case DW_AT_low_pc:
@ -761,8 +762,10 @@ DWARFCompileUnit::Index
else
base_name_to_function_die.Append(ConstString(name).AsCString(), die.GetOffset());
}
if (mangled)
full_name_to_function_die.Append(ConstString(mangled).AsCString(), die.GetOffset());
if (mangled.GetMangledName())
full_name_to_function_die.Append(mangled.GetMangledName().AsCString(), die.GetOffset());
if (mangled.GetDemangledName())
full_name_to_function_die.Append(mangled.GetDemangledName().AsCString(), die.GetOffset());
}
break;
@ -771,8 +774,10 @@ DWARFCompileUnit::Index
{
if (name)
base_name_to_function_die.Append(ConstString(name).AsCString(), die.GetOffset());
if (mangled)
full_name_to_function_die.Append(ConstString(mangled).AsCString(), die.GetOffset());
if (mangled.GetMangledName())
full_name_to_function_die.Append(mangled.GetMangledName().AsCString(), die.GetOffset());
if (mangled.GetDemangledName())
full_name_to_function_die.Append(mangled.GetDemangledName().AsCString(), die.GetOffset());
}
break;