Add MethodImplOptions.AggressiveOptimization and use it for tiering (#20009)

Add MethodImplOptions.AggressiveOptimization and use it for tiering

Part of fix for https://github.com/dotnet/corefx/issues/32235
Workaround for https://github.com/dotnet/coreclr/issues/19751
- Added and set CORJIT_FLAG_AGGRESSIVE_OPT to indicate that a method is flagged with AggressiveOptimization
- For a method flagged with AggressiveOptimization, tiering uses a foreground tier 1 JIT on first call to the method, skipping the tier 0 JIT and call counting
- When tiering is disabled, a method flagged with AggressiveOptimization does not use r2r-pregenerated code
- R2r crossgen does not generate code for a method flagged with AggressiveOptimization

1 files changed, 10 insertions, 12 deletions

diff --git a/src/vm/prestub.cpp b/src/vm/prestub.cpp
index 378dc2e120..1893cf6c23 100644
--- a/src/vm/prestub.cpp
+++ b/src/vm/prestub.cpp
@@ -1745,20 +1745,16 @@ PCODE MethodDesc::DoPrestub(MethodTable *pDispatchingMT)
     // When the TieredCompilationManager has received enough call notifications
     // for this method only then do we back-patch it.
     BOOL fCanBackpatchPrestub = TRUE;
-    BOOL fEligibleForCallCounting = FALSE;
 #ifdef FEATURE_TIERED_COMPILATION
+    BOOL fNeedsCallCounting = FALSE;
     TieredCompilationManager* pTieredCompilationManager = nullptr;
-    BOOL fEligibleForTieredCompilation = IsEligibleForTieredCompilation();
-    BOOL fWasPromotedToTier1 = FALSE;
-    if (fEligibleForTieredCompilation)
+    if (IsEligibleForTieredCompilation() && TieredCompilationManager::RequiresCallCounting(this))
     {
-        fEligibleForCallCounting = g_pConfig->TieredCompilation_CallCounting();
-        if (fEligibleForCallCounting)
-        {
-            pTieredCompilationManager = GetAppDomain()->GetTieredCompilationManager();
-            CallCounter * pCallCounter = GetCallCounter();
-            pCallCounter->OnMethodCalled(this, pTieredCompilationManager, &fCanBackpatchPrestub, &fWasPromotedToTier1);
-        }
+        pTieredCompilationManager = GetAppDomain()->GetTieredCompilationManager();
+        CallCounter * pCallCounter = GetCallCounter();
+        BOOL fWasPromotedToTier1 = FALSE;
+        pCallCounter->OnMethodCalled(this, pTieredCompilationManager, &fCanBackpatchPrestub, &fWasPromotedToTier1);
+        fNeedsCallCounting = !fWasPromotedToTier1;
     }
 #endif
 
@@ -1771,10 +1767,12 @@ PCODE MethodDesc::DoPrestub(MethodTable *pDispatchingMT)
     {
         pCode = GetCodeVersionManager()->PublishVersionableCodeIfNecessary(this, fCanBackpatchPrestub);
 
-        if (pTieredCompilationManager != nullptr && fEligibleForCallCounting && fCanBackpatchPrestub && pCode != NULL && !fWasPromotedToTier1)
+#ifdef FEATURE_TIERED_COMPILATION
+        if (pTieredCompilationManager != nullptr && fNeedsCallCounting && fCanBackpatchPrestub && pCode != NULL)
         {
             pTieredCompilationManager->OnMethodCallCountingStoppedWithoutTier1Promotion(this);
         }
+#endif
 
         fIsPointingToPrestub = IsPointingToPrestub();
     }