Statistic: Bring back printing on exit by default

Turns out several external projects relied on llvm printing statistics
on exit. Let's go back to this behaviour by default and have an optional
parameter to disable it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282532 91177308-0d34-0410-b5e6-96231b3b80d8

Author: matze

include/llvm/ADT/Statistic.h

@@ -151,7 +151,7 @@ class Statistic {
   static llvm::Statistic VARNAME = {DEBUG_TYPE, #VARNAME, DESC, {0}, false}
 
 /// \brief Enable the collection and printing of statistics.
-void EnableStatistics();
+void EnableStatistics(bool PrintOnExit = true);
 
 /// \brief Check if statistics are enabled.
 bool AreStatisticsEnabled();

lib/Support/Statistic.cpp

@@ -45,6 +45,7 @@ static cl::opt<bool> StatsAsJSON("stats-json",
                                  cl::desc("Display statistics as json data"));
 
 static bool Enabled;
+static bool PrintOnExit;
 
 namespace {
 /// StatisticInfo - This class is used in a ManagedStatic so that it is created
@@ -91,12 +92,13 @@ void Statistic::RegisterStatistic() {
 
 // Print information when destroyed, iff command line option is specified.
 StatisticInfo::~StatisticInfo() {
-  if (::Stats)
+  if (::Stats || PrintOnExit)
     llvm::PrintStatistics();
 }
 
-void llvm::EnableStatistics() {
+void llvm::EnableStatistics(bool PrintOnExit) {
   Enabled = true;
+  ::PrintOnExit = PrintOnExit;
 }
 
 bool llvm::AreStatisticsEnabled() {