[BOLT][NFCI] Use StringRef.split in launchPerfProcess

[Amir]

Summary

Use StringRef method instead of reimplementing the splitting.
Incidentally, it also fixes the duplicate printing of the command arguments:

PERF2BOLT: spawning perf job to read branch events
Launching perf: /usr/bin/perf script^@-F^@pid,ip,brstack -F^@pid,ip,brstack pid,ip,brstack -f -i
PERF2BOLT: spawning perf job to read mem events
Launching perf: /usr/bin/perf script^@-F^@pid,event,addr,ip -F^@pid,event,addr,ip pid,event,addr,ip -f -i
PERF2BOLT: spawning perf job to read process events
Launching perf: /usr/bin/perf script^@--show-mmap-events --show-mmap-events -f -i
PERF2BOLT: spawning perf job to read task events
Launching perf: /usr/bin/perf script^@--show-task-events --show-task-events -f -i

Fixes it to:

PERF2BOLT: spawning perf job to read branch events
Launching perf: /usr/bin/perf script -F pid,ip,brstack -f -i
PERF2BOLT: spawning perf job to read mem events
Launching perf: /usr/bin/perf script -F pid,event,addr,ip -f -i
PERF2BOLT: spawning perf job to read process events
Launching perf: /usr/bin/perf script --show-mmap-events -f -i
PERF2BOLT: spawning perf job to read task events
Launching perf: /usr/bin/perf script --show-task-events -f -i

bolt/lib/Profile/DataAggregator.cpp

 
 void DataAggregator::launchPerfProcess(StringRef Name, PerfProcessInfo &PPI,
                                        const char *ArgsString, bool Wait) {
   SmallVector<StringRef, 4> Argv;
 
   outs() << "PERF2BOLT: spawning perf job to read " << Name << '\n';
   Argv.push_back(PerfPath.data());
 
-  char *WritableArgsString = strdup(ArgsString);
-  char *Str = WritableArgsString;
-  do {
-    Argv.push_back(Str);
-    while (*Str && *Str != ' ')
-      ++Str;
-    if (!*Str)
-      break;
-    *Str++ = 0;
-  } while (true);
-
+  StringRef(ArgsString).split(Argv, ' ');
   Argv.push_back("-f");
   Argv.push_back("-i");
   Argv.push_back(Filename.c_str());
 
   if (std::error_code Errc =
           sys::fs::createTemporaryFile("perf.script", "out", PPI.StdoutPath)) {
     errs() << "PERF2BOLT: failed to create temporary file " << PPI.StdoutPath
            << " with error " << Errc.message() << "\n";
void DataAggregator::launchPerfProcess(StringRef Name, PerfProcessInfo &PPI,
   });
 
   if (Wait)
     PPI.PI.ReturnCode = sys::ExecuteAndWait(PerfPath.data(), Argv,
                                             /*envp*/ std::nullopt, Redirects);
   else
     PPI.PI = sys::ExecuteNoWait(PerfPath.data(), Argv, /*envp*/ std::nullopt,
                                 Redirects);
-
-  free(WritableArgsString);
 }
 
 void DataAggregator::processFileBuildID(StringRef FileBuildID) {
   PerfProcessInfo BuildIDProcessInfo;
   launchPerfProcess("buildid list",
                     BuildIDProcessInfo,
                     "buildid-list",
                     /*Wait = */true);