[LegacyPassManager] Demangling function name in ftime-trace output.

[Sockke]

Summary

Demangling compiled C++ function names so that it makes the data more readable in analyzing platform.

[anton-afanasyev]

Thanks, looks good (after reformatting suggested by lint).
Add @aras-p: hi, Aras, just to warn you about output format changing, which may be sensitive for tools like ClangBuildAnalyzer.

[lebedev.ri]

1. Legacy PM is dead. Why change it? What about NewPM?
2. Is this really an UX improvement? Now instead you can't easily find the LLVM IR function. There is a demangler command, but is there a mangler?

[dexonsmith]

I agree with Roman. Those that want demangled names can just pipe through c++filt, but it's hard to go in the other direction, and the mangled names are easier to copy/paste/integrate with other tooling.

[Sockke]

Thanks, sorry for the delayed reply.
Yes, fair point. How about adding an option to determine whether to demangle the function name or not?

[lebedev.ri]

Please can you explain what problem you are trying to solve, on the higher level?

[Sockke]

In D110326#3029826, @lebedev.ri wrote:

Please can you explain what problem you are trying to solve, on the higher level?

Currently, I just want to make the output data generated by ftime-trace more readable in Chrome.

[anton-afanasyev]

In D110326#3029804, @Sockke wrote:

How about adding an option to determine whether to demangle the function name or not?

Making this a non-default option sounds good.

[Sockke]

This comment was removed by Sockke.

[Sockke]

In D110326#3036509, @anton-afanasyev wrote:

In D110326#3029804, @Sockke wrote:

How about adding an option to determine whether to demangle the function name or not?

Making this a non-default option sounds good.

Sorry for delayed response. Thanks for your review, what is the follow-up of this patch？ Any other thoughts?

[anton-afanasyev]

In D110326#3061751, @Sockke wrote:

In D110326#3036509, @anton-afanasyev wrote:

In D110326#3029804, @Sockke wrote:

How about adding an option to determine whether to demangle the function name or not?

Making this a non-default option sounds good.

Sorry for delayed response. Thanks for your review, what is the follow-up of this patch？ Any other thoughts?

As before, I believe making this a non-default option would be a good compromise.

[lebedev.ri]

This review seems to be stuck/dead, consider abandoning if no longer relevant.

llvm/lib/IR/LegacyPassManager.cpp

 //===- LegacyPassManager.cpp - LLVM Pass Infrastructure Implementation ----===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the legacy LLVM Pass Manager infrastructure.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/LegacyPassManagers.h"
 #include "llvm/IR/LegacyPassNameParser.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/PassTimingInfo.h"
 #include "llvm/IR/PrintPasses.h"
 #include "llvm/IR/StructuralHash.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Demangle/Demangle.h"
 #include <algorithm>
 #include <unordered_set>
 using namespace llvm;
 
 // See PassManagers.h for Pass Manager infrastructure overview.
 
 //===----------------------------------------------------------------------===//
 // Pass debugging information.  Often it is useful to find out what pass is
bool FPPassManager::runOnFunction(Function &F) {
   StringMap<std::pair<unsigned, unsigned>> FunctionToInstrCount;
   bool EmitICRemark = M.shouldEmitInstrCountChangedRemark();
   // Collect the initial size of the module.
   if (EmitICRemark) {
     InstrCount = initSizeRemarkInfo(M, FunctionToInstrCount);
     FunctionSize = F.getInstructionCount();
   }
 
-  llvm::TimeTraceScope FunctionScope("OptFunction", F.getName());
+  llvm::TimeTraceScope FunctionScope("OptFunction", StringRef(demangle(F.getName().str())));
 
   for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
     FunctionPass *FP = getContainedPass(Index);
     bool LocalChanged = false;
 
     llvm::TimeTraceScope PassScope("RunPass", FP->getPassName());
 
     dumpPassInfo(FP, EXECUTION_MSG, ON_FUNCTION_MSG, F.getName());