Small cleanups in SysV classification.

- Clean up/clarify the logic in CEEInfo::getSystemVAmd64PassStructInRegisterDescriptor
- Move a static helper function off of MethodTable

3 files changed, 14 insertions, 39 deletions

diff --git a/src/vm/jitinterface.cpp b/src/vm/jitinterface.cpp
index c331a30001..6ca4299f63 100644
--- a/src/vm/jitinterface.cpp
+++ b/src/vm/jitinterface.cpp
@@ -2577,14 +2577,14 @@ bool CEEInfo::getSystemVAmd64PassStructInRegisterDescriptor(
 
     _ASSERTE(structPassInRegDescPtr != nullptr);
     TypeHandle th(structHnd);
+
+    structPassInRegDescPtr->passedInRegisters = false;
     
     // Make sure this is a value type.
     if (th.IsValueType())
     {
         _ASSERTE(CorInfoType2UnixAmd64Classification(th.GetInternalCorElementType()) == SystemVClassificationTypeStruct);
 
-        MethodTable* methodTablePtr = nullptr;
-
         // The useNativeLayout in this case tracks whether the classification
         // is for a native layout of the struct or not.
         // If the struct has special marshaling it has a native layout. 
@@ -2592,43 +2592,23 @@ bool CEEInfo::getSystemVAmd64PassStructInRegisterDescriptor(
         // For structs with no native layout, the managed layout should be used
         // even if classified for the purposes of marshaling/PInvoke passing.
         bool useNativeLayout = false;
+        MethodTable* methodTablePtr = nullptr;
         if (!th.IsTypeDesc())
         {
             methodTablePtr = th.AsMethodTable();
-            _ASSERTE(methodTablePtr != nullptr);
-        }
-        else if (th.IsTypeDesc())
-        {
-            if (th.IsNativeValueType())
-            {
-                methodTablePtr = th.AsNativeValueType();
-                useNativeLayout = true;
-                _ASSERTE(methodTablePtr != nullptr);
-            }
-            else
-            {
-                _ASSERTE(false && "Unhandled TypeHandle for struct!");
-            }
-        }
-
-        bool isPassableInRegs = false;
-
-        if (useNativeLayout)
-        {
-            _ASSERTE(th.IsNativeValueType());
-            isPassableInRegs = methodTablePtr->GetLayoutInfo()->IsNativeStructPassedInRegisters();
         }
         else
         {
-            _ASSERTE(!th.IsNativeValueType());
-            isPassableInRegs = methodTablePtr->IsRegPassedStruct();
-        }
+            _ASSERTE(th.IsNativeValueType());
 
-        if (!isPassableInRegs)
-        {
-            structPassInRegDescPtr->passedInRegisters = false;
+            useNativeLayout = true;
+            methodTablePtr = th.AsNativeValueType();
         }
-        else
+        _ASSERTE(methodTablePtr != nullptr);
+
+        bool canPassInRegisters = useNativeLayout ? methodTablePtr->GetLayoutInfo()->IsNativeStructPassedInRegisters()
+                                                : methodTablePtr->IsRegPassedStruct();
+        if (canPassInRegisters)
         {
             SystemVStructRegisterPassingHelper helper((unsigned int)th.GetSize());
             bool result = methodTablePtr->ClassifyEightBytes(&helper, 0, 0, useNativeLayout);
@@ -2647,10 +2627,8 @@ bool CEEInfo::getSystemVAmd64PassStructInRegisterDescriptor(
                 structPassInRegDescPtr->eightByteOffsets[i] = helper.eightByteOffsets[i];
             }
         }
-    }
-    else
-    {
-        structPassInRegDescPtr->passedInRegisters = false;
+
+        _ASSERTE(structPassInRegDescPtr->passedInRegisters == canPassInRegisters);
     }
 
     EE_TO_JIT_TRANSITION();
diff --git a/src/vm/methodtable.cpp b/src/vm/methodtable.cpp
index ca8ababd4f..f06138ad60 100644
--- a/src/vm/methodtable.cpp
+++ b/src/vm/methodtable.cpp
@@ -2316,7 +2316,7 @@ bool MethodTable::ClassifyEightBytes(SystemVStructRegisterPassingHelperPtr helpe
 // If we have a field classification already, but there is a union, we must merge the classification type of the field. Returns the
 // new, merged classification type.
 /* static */
-SystemVClassificationType MethodTable::ReClassifyField(SystemVClassificationType originalClassification, SystemVClassificationType newFieldClassification)
+static SystemVClassificationType ReClassifyField(SystemVClassificationType originalClassification, SystemVClassificationType newFieldClassification)
 {
     _ASSERTE((newFieldClassification == SystemVClassificationTypeInteger) ||
              (newFieldClassification == SystemVClassificationTypeIntegerReference) ||
diff --git a/src/vm/methodtable.h b/src/vm/methodtable.h
index 2dd532a6b0..a7cfce779a 100644
--- a/src/vm/methodtable.h
+++ b/src/vm/methodtable.h
@@ -1046,9 +1046,6 @@ public:
     void CheckRunClassInitAsIfConstructingThrowing();
 
 #if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING_ITF)
-    // Helper function for ClassifyEightBytesWithManagedLayout and ClassifyEightBytesWithNativeLayout
-    static SystemVClassificationType ReClassifyField(SystemVClassificationType originalClassification, SystemVClassificationType newFieldClassification);
-
     // Builds the internal data structures and classifies struct eightbytes for Amd System V calling convention.
     bool ClassifyEightBytes(SystemVStructRegisterPassingHelperPtr helperPtr, unsigned int nestingLevel, unsigned int startOffsetOfStruct, bool isNativeStruct);
 #endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING_ITF)