added a lightweight GC profiling option

src/inc/corprof.idl

@@ -627,9 +627,13 @@ typedef enum
 
     COR_PRF_HIGH_DISABLE_TIERED_COMPILATION         = 0x00000008,
 
+    COR_PRF_HIGH_BASIC_GC                           = 0x00000010,
+
     COR_PRF_HIGH_REQUIRE_PROFILE_IMAGE              = 0,
 
-    COR_PRF_HIGH_ALLOWABLE_AFTER_ATTACH             = COR_PRF_HIGH_IN_MEMORY_SYMBOLS_UPDATED | COR_PRF_HIGH_MONITOR_DYNAMIC_FUNCTION_UNLOADS,
+    COR_PRF_HIGH_ALLOWABLE_AFTER_ATTACH             = COR_PRF_HIGH_IN_MEMORY_SYMBOLS_UPDATED | 
+                                                      COR_PRF_HIGH_MONITOR_DYNAMIC_FUNCTION_UNLOADS | 
+                                                      COR_PRF_HIGH_BASIC_GC,
 
     // MONITOR_IMMUTABLE represents all flags that may only be set during initialization.
     // Trying to change any of these flags elsewhere will result in a

src/inc/profilepriv.inl

@@ -727,6 +727,20 @@ inline BOOL CORProfilerDisableTieredCompilation()
          ((&g_profControlBlock)->dwEventMaskHigh & COR_PRF_HIGH_DISABLE_TIERED_COMPILATION));
 }
 
+inline BOOL CORProfilerTrackBasicGC()
+{
+    CONTRACTL 
+    {
+        NOTHROW;
+        GC_NOTRIGGER;
+        CANNOT_TAKE_LOCK;
+    }
+    CONTRACTL_END;
+
+    return (CORProfilerPresent() &&
+         ((&g_profControlBlock)->dwEventMaskHigh & COR_PRF_HIGH_BASIC_GC));
+}
+
 #if defined(PROFILING_SUPPORTED) && !defined(CROSSGEN_COMPILE)
 
 #if defined(FEATURE_PROFAPI_ATTACH_DETACH)

src/pal/prebuilt/inc/corprof.h

@@ -544,8 +544,9 @@ enum __MIDL___MIDL_itf_corprof_0000_0000_0006
         COR_PRF_HIGH_IN_MEMORY_SYMBOLS_UPDATED	= 0x2,
         COR_PRF_HIGH_MONITOR_DYNAMIC_FUNCTION_UNLOADS	= 0x4,
         COR_PRF_HIGH_DISABLE_TIERED_COMPILATION	= 0x8,
+        COR_PRF_HIGH_BASIC_GC = 0x10,
         COR_PRF_HIGH_REQUIRE_PROFILE_IMAGE	= 0,
-        COR_PRF_HIGH_ALLOWABLE_AFTER_ATTACH	= ( COR_PRF_HIGH_IN_MEMORY_SYMBOLS_UPDATED | COR_PRF_HIGH_MONITOR_DYNAMIC_FUNCTION_UNLOADS ) ,
+        COR_PRF_HIGH_ALLOWABLE_AFTER_ATTACH	= ( COR_PRF_HIGH_IN_MEMORY_SYMBOLS_UPDATED | COR_PRF_HIGH_MONITOR_DYNAMIC_FUNCTION_UNLOADS | COR_PRF_HIGH_BASIC_GC) ,
         COR_PRF_HIGH_MONITOR_IMMUTABLE	= COR_PRF_HIGH_DISABLE_TIERED_COMPILATION
     } 	COR_PRF_HIGH_MONITOR;
 

src/vm/eetoprofinterfaceimpl.cpp

@@ -6196,7 +6196,7 @@ HRESULT EEToProfInterfaceImpl::GarbageCollectionStarted(int cGenerations, BOOL g
         LL_INFO10000, 
         "**PROF: GarbageCollectionStarted.\n"));
 
-    _ASSERTE(!GCHeapUtilities::GetGCHeap()->IsConcurrentGCEnabled());
+    _ASSERTE(!CORProfilerTrackGC() || !GCHeapUtilities::GetGCHeap()->IsConcurrentGCEnabled());
 
     {            
         // All callbacks are really NOTHROW, but that's enforced partially by the profiler,
@@ -6233,7 +6233,7 @@ HRESULT EEToProfInterfaceImpl::GarbageCollectionFinished()
         LL_INFO10000, 
         "**PROF: GarbageCollectionFinished.\n"));
 
-    _ASSERTE(!GCHeapUtilities::GetGCHeap()->IsConcurrentGCEnabled());
+    _ASSERTE(!CORProfilerTrackGC() || !GCHeapUtilities::GetGCHeap()->IsConcurrentGCEnabled());
 
     {        
         // All callbacks are really NOTHROW, but that's enforced partially by the profiler,

src/vm/gcenv.ee.cpp

@@ -742,17 +742,24 @@ void GCToEEInterface::DiagGCStart(int gen, bool isInduced)
 void GCToEEInterface::DiagUpdateGenerationBounds()
 {
 #ifdef GC_PROFILING
-    if (CORProfilerTrackGC())
+    if (CORProfilerTrackGC() || CORProfilerTrackBasicGC())
         UpdateGenerationBounds();
 #endif // GC_PROFILING
 }
 
 void GCToEEInterface::DiagGCEnd(size_t index, int gen, int reason, bool fConcurrent)
 {
 #ifdef GC_PROFILING
+    // We were only doing generation bounds and GC finish callback for non concurrent GCs so
+    // I am keeping that behavior to not break profilers. But if BasicGC monitoring is enabled
+    // we will do these for all GCs.
     if (!fConcurrent)
     {
         GCProfileWalkHeap();
+    }
+
+    if (CORProfilerTrackBasicGC() || (!fConcurrent && CORProfilerTrackGC()))
+    {
         DiagUpdateGenerationBounds();
         GarbageCollectionFinishedCallback();
     }

src/vm/proftoeeinterfaceimpl.cpp

@@ -684,7 +684,7 @@ void __stdcall GarbageCollectionStartedCallback(int generation, BOOL induced)
 
     // Notify the profiler of start of the collection
     {
-        BEGIN_PIN_PROFILER(CORProfilerTrackGC());
+        BEGIN_PIN_PROFILER(CORProfilerTrackGC() || CORProfilerTrackBasicGC());
         BOOL generationCollected[COR_PRF_GC_LARGE_OBJECT_HEAP+1];
         if (generation == COR_PRF_GC_GEN_2)
             generation = COR_PRF_GC_LARGE_OBJECT_HEAP;
@@ -718,7 +718,7 @@ void __stdcall GarbageCollectionFinishedCallback()
 #ifdef PROFILING_SUPPORTED
     // Notify the profiler of end of the collection
     {
-        BEGIN_PIN_PROFILER(CORProfilerTrackGC());
+        BEGIN_PIN_PROFILER(CORProfilerTrackGC() || CORProfilerTrackBasicGC());
         g_profControlBlock.pProfInterface->GarbageCollectionFinished();
         END_PIN_PROFILER();
     }
@@ -858,7 +858,7 @@ void __stdcall UpdateGenerationBounds()
 
 #ifdef PROFILING_SUPPORTED
     // Notify the profiler of start of the collection
-    if (CORProfilerTrackGC())
+    if (CORProfilerTrackGC() || CORProfilerTrackBasicGC())
     {
         // generate a new generation table
         GenerationTable *newGenerationTable = new (nothrow) GenerationTable();