JIT: pgo/devirt diagnostic improvements (#53247)

Several changes to help better diagnose PGO and devirtualization issues:
* Report the source of the PGO data to the jit
* Report the reason for a devirtualization failure to the jit
* Add checking mode that compares result of devirtualization to class profile
* Add reporting mode to assess overall rates of devirtualization failure
  when the jit has exact type information.

Also fix a loophole where in some case we'd still devirtualize if not
optimizing.

Note crossgen2 does not yet set devirtualization failure reasons.

4 files changed, 40 insertions, 10 deletions

diff --git a/src/coreclr/inc/corinfo.h b/src/coreclr/inc/corinfo.h
index 197450f279d..231b669ebee 100644
--- a/src/coreclr/inc/corinfo.h
+++ b/src/coreclr/inc/corinfo.h
@@ -1602,6 +1602,21 @@ struct CORINFO_CALL_INFO
     bool                    wrapperDelegateInvoke;
 };
 
+enum CORINFO_DEVIRTUALIZATION_DETAIL
+{
+    CORINFO_DEVIRTUALIZATION_UNKNOWN,         // no details available
+    CORINFO_DEVIRTUALIZATION_SUCCESS,         // devirtualization was successful
+    CORINFO_DEVIRTUALIZATION_FAILED_CANON,    // object class was canonical
+    CORINFO_DEVIRTUALIZATION_FAILED_COM,      // object class was com
+    CORINFO_DEVIRTUALIZATION_FAILED_CAST,     // object class could not be cast to interface class
+    CORINFO_DEVIRTUALIZATION_FAILED_LOOKUP,   // interface method could not be found
+    CORINFO_DEVIRTUALIZATION_FAILED_DIM,      // interface method was default interface method
+    CORINFO_DEVIRTUALIZATION_FAILED_SUBCLASS, // object not subclass of base class
+    CORINFO_DEVIRTUALIZATION_FAILED_SLOT,     // virtual method installed via explicit override
+    CORINFO_DEVIRTUALIZATION_FAILED_BUBBLE,   // devirtualization crossed version bubble
+    CORINFO_DEVIRTUALIZATION_COUNT,           // sentinel for maximum value
+};
+
 struct CORINFO_DEVIRTUALIZATION_INFO
 {
     //
@@ -1617,10 +1632,12 @@ struct CORINFO_DEVIRTUALIZATION_INFO
     //      invariant is `resolveVirtualMethod(...) == (devirtualizedMethod != nullptr)`.
     // - requiresInstMethodTableArg is set to TRUE if the devirtualized method requires a type handle arg.
     // - exactContext is set to wrapped CORINFO_CLASS_HANDLE of devirt'ed method table.
+    // - details on the computation done by the jit host
     //
-    CORINFO_METHOD_HANDLE       devirtualizedMethod;
-    bool                        requiresInstMethodTableArg;
-    CORINFO_CONTEXT_HANDLE      exactContext;
+    CORINFO_METHOD_HANDLE           devirtualizedMethod;
+    bool                            requiresInstMethodTableArg;
+    CORINFO_CONTEXT_HANDLE          exactContext;
+    CORINFO_DEVIRTUALIZATION_DETAIL detail;
 };
 
 //----------------------------------------------------------------------------
diff --git a/src/coreclr/inc/corjit.h b/src/coreclr/inc/corjit.h
index b6c97d9f5ab..d4a22f2ee3e 100644
--- a/src/coreclr/inc/corjit.h
+++ b/src/coreclr/inc/corjit.h
@@ -396,6 +396,17 @@ public:
         int32_t Other;
     };
 
+    enum class PgoSource
+    {
+        Unknown = 0,    // PGO data source unknown
+        Static = 1,     // PGO data comes from embedded R2R profile data
+        Dynamic = 2,    // PGO data comes from current run
+        Blend = 3,      // PGO data comes from blend of prior runs and current run
+        Text = 4,       // PGO data comes from text file
+        IBC = 5,        // PGO data from classic IBC
+        Sampling= 6,    // PGO data derived from sampling
+    };
+
 #define DEFAULT_UNKNOWN_TYPEHANDLE 1
 #define UNKNOWN_TYPEHANDLE_MIN 1
 #define UNKNOWN_TYPEHANDLE_MAX 33
@@ -412,8 +423,9 @@ public:
             PgoInstrumentationSchema **pSchema,                    // OUT: pointer to the schema table (array) which describes the instrumentation results
                                                                    // (pointer will not remain valid after jit completes).
             uint32_t *                 pCountSchemaItems,          // OUT: pointer to the count of schema items in `pSchema` array.
-            uint8_t **                 pInstrumentationData        // OUT: `*pInstrumentationData` is set to the address of the instrumentation data
+            uint8_t **                 pInstrumentationData,       // OUT: `*pInstrumentationData` is set to the address of the instrumentation data
                                                                    // (pointer will not remain valid after jit completes).
+            PgoSource *                pPgoSource                  // OUT: value describing source of pgo data
             ) = 0;
 
     // Allocate a profile buffer for use in the current process
diff --git a/src/coreclr/inc/icorjitinfoimpl_generated.h b/src/coreclr/inc/icorjitinfoimpl_generated.h
index ebd9813e2c4..c65a0840d6f 100644
--- a/src/coreclr/inc/icorjitinfoimpl_generated.h
+++ b/src/coreclr/inc/icorjitinfoimpl_generated.h
@@ -678,7 +678,8 @@ JITINTERFACE_HRESULT getPgoInstrumentationResults(
           CORINFO_METHOD_HANDLE ftnHnd,
           ICorJitInfo::PgoInstrumentationSchema** pSchema,
           uint32_t* pCountSchemaItems,
-          uint8_t** pInstrumentationData) override;
+          uint8_t** pInstrumentationData,
+          ICorJitInfo::PgoSource* pgoSource) override;
 
 JITINTERFACE_HRESULT allocPgoInstrumentationBySchema(
           CORINFO_METHOD_HANDLE ftnHnd,
diff --git a/src/coreclr/inc/jiteeversionguid.h b/src/coreclr/inc/jiteeversionguid.h
index 54ed6978c7a..548fcf5f7f3 100644
--- a/src/coreclr/inc/jiteeversionguid.h
+++ b/src/coreclr/inc/jiteeversionguid.h
@@ -43,11 +43,11 @@ typedef const GUID *LPCGUID;
 #define GUID_DEFINED
 #endif // !GUID_DEFINED
 
-constexpr GUID JITEEVersionIdentifier = { /* 895f5d24-eb01-4aff-ad6c-1efc6a91498a */
-    0x895f5d24,
-    0xeb01,
-    0x4aff,
-    {0xad, 0x6c, 0x1e, 0xfc, 0x6a, 0x91, 0x49, 0x8a}
+constexpr GUID JITEEVersionIdentifier = { /* 81a5e384-8ca5-4947-8b2e-1d76556728fd */
+    0x81a5e384,
+    0x8ca5,
+    0x4947,
+    {0x8b, 0x2e, 0x1d, 0x76, 0x55, 0x67, 0x28, 0xfd}
 };
 
 //////////////////////////////////////////////////////////////////////////////////////////////////////////