maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[lldb] Remove cache in get_demangled_name_without_arguments 

This function has a single-value caching based on function local static variables.

This causes two problems:

* There is no synchronization, so this function randomly returns the demangled
  name of other functions that are demangled at the same time.
* The 1-element cache is not very effective (the cache rate is around 0% when
  running the LLDB test suite that calls this function around 30k times).

I would propose just removing it.

To prevent anyone else the git archeology: the static result variables were
originally added as this returned a ConstString reference, but that has since
been changed so that this returns by value.

Reviewed By: #lldb, JDevlieghere, shafik

Differential Revision: https://reviews.llvm.org/D103107
This commit is contained in:
Raphael Isemann 2021-05-26 17:52:51 +02:00
parent 1b47a3de48
commit d28bc54ff4
1 changed files with 6 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
lldb/source/Core/Mangled.cpp
View File

@ -35,26 +35,8 @@ static inline bool cstring_is_mangled(llvm::StringRef s) {
return Mangled::GetManglingScheme(s) != Mangled::eManglingSchemeNone;
}
static ConstString
get_demangled_name_without_arguments(ConstString mangled,
ConstString demangled) {
// This pair is <mangled name, demangled name without function arguments>
static std::pair<ConstString, ConstString>
g_most_recent_mangled_to_name_sans_args;
// Need to have the mangled & demangled names we're currently examining as
// statics so we can return a const ref to them at the end of the func if we
// don't have anything better.
static ConstString g_last_mangled;
static ConstString g_last_demangled;
if (mangled && g_most_recent_mangled_to_name_sans_args.first == mangled) {
return g_most_recent_mangled_to_name_sans_args.second;
}
g_last_demangled = demangled;
g_last_mangled = mangled;
static ConstString GetDemangledNameWithoutArguments(ConstString mangled,
ConstString demangled) {
const char *mangled_name_cstr = mangled.GetCString();
if (demangled && mangled_name_cstr && mangled_name_cstr[0]) {
@ -73,17 +55,13 @@ get_demangled_name_without_arguments(ConstString mangled,
if (!cxx_method.GetContext().empty())
shortname = cxx_method.GetContext().str() + "::";
shortname += cxx_method.GetBasename().str();
ConstString result(shortname.c_str());
g_most_recent_mangled_to_name_sans_args.first = mangled;
g_most_recent_mangled_to_name_sans_args.second = result;
return g_most_recent_mangled_to_name_sans_args.second;
return ConstString(shortname);
}
}
}
if (demangled)
return g_last_demangled;
return g_last_mangled;
return demangled;
return mangled;
}
#pragma mark Mangled
@ -347,7 +325,7 @@ ConstString Mangled::GetName(Mangled::NamePreference preference) const {
ConstString demangled = GetDemangledName();
if (preference == ePreferDemangledWithoutArguments) {
return get_demangled_name_without_arguments(m_mangled, demangled);
return GetDemangledNameWithoutArguments(m_mangled, demangled);
}
if (preference == ePreferDemangled) {
// Call the accessor to make sure we get a demangled name in case it hasn't