Backend -ftime-trace entries should be demangled

[Trass3r]

Bugzilla Link	46556
Version	trunk
OS	All

Extended Description

While Frontend entries are properly demangled the Backend entries are not:

"name":"OptFunction","args":{"detail":"ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC2EPKcRKS3"}

[Trass3r]

Which is because of this

llvm-project/llvm/lib/IR/LegacyPassManager.cpp

Line 1411 in 961439c

llvm::TimeTraceScope FunctionScope("OptFunction", F.getName());

not using something like this

llvm-project/clang/lib/CodeGen/CodeGenModule.cpp

Lines 3570 to 3576 in 781b491

	llvm::TimeTraceScope TimeScope("CodeGen Function", [&]() {
	std::string Name;
	llvm::raw_string_ostream OS(Name);
	FD->getNameForDiagnostic(OS, getContext().getPrintingPolicy(),
	/*Qualified=*/true);
	return Name;
	});

Of course the problem is that in IR (llvm::Function) you only have the mangled name. Not sure if something like abi::__cxa_demangle(name, NULL, NULL, &status) is desirable there.

Can't find anything equivalent in the new pass manager:

llvm-project/llvm/lib/IR/PassManager.cpp

Line 124 in 961439c

PreservedAnalyses PassPA = Pass->run(F, FAM);

But seems like the old OptFunction code is still being used.