[llvm][Timer] Use global TimerGroups for both new pass manager and old pass manager timers (#130375)

Additionally, remove the behavior for both pass manager's timer manager
classes (`PassTimingInfo` for the old pass manager and
`TimePassesHandler` for the new pass manager) where these classes would
print the values of their timers upon destruction.

Currently, each pass manager manages their own `TimerGroup`s. This is
problematic because of duplicate `TimerGroup`s (both pass managers have
a `TimerGroup` for pass times with identical names and descriptions).
The result is that in Clang, `-ftime-report` has two "Pass execution
timing report" sections (one for the new pass manager which manages
optimization passes, and one for the old pass manager which manages the
backend). The result of this change is that Clang's `-ftime-report` now
prints both optimization and backend pass timing info in a unified "Pass
execution timing report" section.

Moving the ownership of the `TimerGroups` to globals also makes it
easier to implement JSON-formatted `-ftime-report`. This was not
possible with the old structure because the two pass managers were
created and destroyed in far parts of the codebase and outputting JSON
requires the printing logic to be at the same place because of
formatting.

Previous discourse discussion:
https://discourse.llvm.org/t/difficulties-with-implementing-json-formatted-ftime-report/84353

1 files changed, 21 insertions, 5 deletions

diff --git a/llvm/lib/Support/Timer.cpp b/llvm/lib/Support/Timer.cpp
index eca7268..4d3b4f7 100644
--- a/llvm/lib/Support/Timer.cpp
+++ b/llvm/lib/Support/Timer.cpp
@@ -222,16 +222,27 @@ public:
              StringRef GroupDescription) {
     sys::SmartScopedLock<true> L(timerLock());
 
-    std::pair<TimerGroup*, Name2TimerMap> &GroupEntry = Map[GroupName];
-
-    if (!GroupEntry.first)
-      GroupEntry.first = new TimerGroup(GroupName, GroupDescription);
-
+    std::pair<TimerGroup *, Name2TimerMap> &GroupEntry =
+        getGroupEntry(GroupName, GroupDescription);
     Timer &T = GroupEntry.second[Name];
     if (!T.isInitialized())
       T.init(Name, Description, *GroupEntry.first);
     return T;
   }
+
+  TimerGroup &getTimerGroup(StringRef GroupName, StringRef GroupDescription) {
+    return *getGroupEntry(GroupName, GroupDescription).first;
+  }
+
+private:
+  std::pair<TimerGroup *, Name2TimerMap> &
+  getGroupEntry(StringRef GroupName, StringRef GroupDescription) {
+    std::pair<TimerGroup *, Name2TimerMap> &GroupEntry = Map[GroupName];
+    if (!GroupEntry.first)
+      GroupEntry.first = new TimerGroup(GroupName, GroupDescription);
+
+    return GroupEntry;
+  }
 };
 
 }
@@ -244,6 +255,11 @@ NamedRegionTimer::NamedRegionTimer(StringRef Name, StringRef Description,
                      : &namedGroupedTimers().get(Name, Description, GroupName,
                                                  GroupDescription)) {}
 
+TimerGroup &NamedRegionTimer::getNamedTimerGroup(StringRef GroupName,
+                                                 StringRef GroupDescription) {
+  return namedGroupedTimers().getTimerGroup(GroupName, GroupDescription);
+}
+
 //===----------------------------------------------------------------------===//
 //   TimerGroup Implementation
 //===----------------------------------------------------------------------===//