[NFC][Coro] Add helpers for coro cloning with a TimeTraceScope (#112948)

A helper (2 overloads) that consolidates corocloner creation and the
actual cloning. The helpers create a TimeTraceScope to make it easier to
see how long the cloning takes.

Extracted from #109032 (commit 1)

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

@@ -60,6 +60,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Coroutines/ABI.h"
 #include "llvm/Transforms/Coroutines/CoroInstr.h"
@@ -118,7 +119,6 @@ class CoroCloner {
 
   TargetTransformInfo &TTI;
 
-public:
   /// Create a cloner for a switch lowering.
   CoroCloner(Function &OrigF, const Twine &Suffix, coro::Shape &Shape,
              Kind FKind, TargetTransformInfo &TTI)
@@ -140,6 +140,30 @@ class CoroCloner {
     assert(ActiveSuspend && "need active suspend point for continuation");
   }
 
+public:
+  /// Create a clone for a switch lowering.
+  static Function *createClone(Function &OrigF, const Twine &Suffix,
+                               coro::Shape &Shape, Kind FKind,
+                               TargetTransformInfo &TTI) {
+    TimeTraceScope FunctionScope("CoroCloner");
+
+    CoroCloner Cloner(OrigF, Suffix, Shape, FKind, TTI);
+    Cloner.create();
+    return Cloner.getFunction();
+  }
+
+  /// Create a clone for a continuation lowering.
+  static Function *createClone(Function &OrigF, const Twine &Suffix,
+                               coro::Shape &Shape, Function *NewF,
+                               AnyCoroSuspendInst *ActiveSuspend,
+                               TargetTransformInfo &TTI) {
+    TimeTraceScope FunctionScope("CoroCloner");
+
+    CoroCloner Cloner(OrigF, Suffix, Shape, NewF, ActiveSuspend, TTI);
+    Cloner.create();
+    return Cloner.getFunction();
+  }
+
   Function *getFunction() const {
     assert(NewF != nullptr && "declaration not yet set");
     return NewF;
@@ -1466,13 +1490,16 @@ struct SwitchCoroutineSplitter {
                     TargetTransformInfo &TTI) {
     assert(Shape.ABI == coro::ABI::Switch);
 
+    // Create a resume clone by cloning the body of the original function,
+    // setting new entry block and replacing coro.suspend an appropriate value
+    // to force resume or cleanup pass for every suspend point.
     createResumeEntryBlock(F, Shape);
-    auto *ResumeClone =
-        createClone(F, ".resume", Shape, CoroCloner::Kind::SwitchResume, TTI);
-    auto *DestroyClone =
-        createClone(F, ".destroy", Shape, CoroCloner::Kind::SwitchUnwind, TTI);
-    auto *CleanupClone =
-        createClone(F, ".cleanup", Shape, CoroCloner::Kind::SwitchCleanup, TTI);
+    auto *ResumeClone = CoroCloner::createClone(
+        F, ".resume", Shape, CoroCloner::Kind::SwitchResume, TTI);
+    auto *DestroyClone = CoroCloner::createClone(
+        F, ".destroy", Shape, CoroCloner::Kind::SwitchUnwind, TTI);
+    auto *CleanupClone = CoroCloner::createClone(
+        F, ".cleanup", Shape, CoroCloner::Kind::SwitchCleanup, TTI);
 
     postSplitCleanup(*ResumeClone);
     postSplitCleanup(*DestroyClone);
@@ -1562,17 +1589,6 @@ struct SwitchCoroutineSplitter {
   }
 
 private:
-  // Create a resume clone by cloning the body of the original function, setting
-  // new entry block and replacing coro.suspend an appropriate value to force
-  // resume or cleanup pass for every suspend point.
-  static Function *createClone(Function &F, const Twine &Suffix,
-                               coro::Shape &Shape, CoroCloner::Kind FKind,
-                               TargetTransformInfo &TTI) {
-    CoroCloner Cloner(F, Suffix, Shape, FKind, TTI);
-    Cloner.create();
-    return Cloner.getFunction();
-  }
-
   // Create an entry block for a resume function with a switch that will jump to
   // suspend points.
   static void createResumeEntryBlock(Function &F, coro::Shape &Shape) {
@@ -1872,7 +1888,8 @@ void coro::AsyncABI::splitCoroutine(Function &F, coro::Shape &Shape,
     auto *Suspend = Shape.CoroSuspends[Idx];
     auto *Clone = Clones[Idx];
 
-    CoroCloner(F, "resume." + Twine(Idx), Shape, Clone, Suspend, TTI).create();
+    CoroCloner::createClone(F, "resume." + Twine(Idx), Shape, Clone, Suspend,
+                            TTI);
   }
 }
 
@@ -2001,7 +2018,8 @@ void coro::AnyRetconABI::splitCoroutine(Function &F, coro::Shape &Shape,
     auto Suspend = Shape.CoroSuspends[i];
     auto Clone = Clones[i];
 
-    CoroCloner(F, "resume." + Twine(i), Shape, Clone, Suspend, TTI).create();
+    CoroCloner::createClone(F, "resume." + Twine(i), Shape, Clone, Suspend,
+                            TTI);
   }
 }