Introduce HandleKindDataIsInvariant helper (#99744)

* Introduce `HandleKindDataIsInvariant` helper

Small helper to identify if a handle kind is invariant.

* Update src/coreclr/jit/gentree.cpp

Co-authored-by: Filip Navara <[email protected]>

---------

Co-authored-by: Filip Navara <[email protected]>

Author: BruceForstall

src/coreclr/jit/fgdiagnostic.cpp

@@ -3411,20 +3411,17 @@ void Compiler::fgDebugCheckFlags(GenTree* tree, BasicBlock* block)
                 GenTreeFlags handleKind = op1->GetIconHandleFlag();
 
                 // Some of these aren't handles to invariant data...
-                if ((handleKind == GTF_ICON_STATIC_HDL) || // Pointer to a mutable class Static variable
-                    (handleKind == GTF_ICON_BBC_PTR) ||    // Pointer to a mutable basic block count value
-                    (handleKind == GTF_ICON_FTN_ADDR) ||   // Pointer to a potentially mutable VM slot
-                    (handleKind == GTF_ICON_GLOBAL_PTR))   // Pointer to mutable data from the VM state
+                if (GenTree::HandleKindDataIsInvariant(handleKind) && (handleKind != GTF_ICON_FTN_ADDR))
+                {
+                    expectedFlags |= GTF_IND_INVARIANT;
+                }
+                else
                 {
                     // For statics, we expect the GTF_GLOB_REF to be set. However, we currently
                     // fail to set it in a number of situations, and so this check is disabled.
                     // TODO: enable checking of GTF_GLOB_REF.
                     // expectedFlags |= GTF_GLOB_REF;
                 }
-                else // All the other handle indirections are considered invariant
-                {
-                    expectedFlags |= GTF_IND_INVARIANT;
-                }
 
                 // Currently we expect all indirections with constant addresses to be nonfaulting.
                 expectedFlags |= GTF_IND_NONFAULTING;

src/coreclr/jit/gentree.cpp

@@ -7726,8 +7726,8 @@ GenTreeFlags Compiler::gtTokenToIconFlags(unsigned token)
 //    Returns a GT_IND node representing value at the address provided by 'addr'
 //
 // Notes:
-//    The GT_IND node is marked as non-faulting
-//    If the indType is GT_REF we also mark the indNode as GTF_GLOB_REF
+//    The GT_IND node is marked as non-faulting.
+//    If the indirection is not invariant, we also mark the indNode as GTF_GLOB_REF.
 //
 GenTree* Compiler::gtNewIndOfIconHandleNode(var_types indType, size_t addr, GenTreeFlags iconFlags, bool isInvariant)
 {
@@ -7736,9 +7736,7 @@ GenTree* Compiler::gtNewIndOfIconHandleNode(var_types indType, size_t addr, GenT
 
     if (isInvariant)
     {
-        assert(iconFlags != GTF_ICON_STATIC_HDL); // Pointer to a mutable class Static variable
-        assert(iconFlags != GTF_ICON_BBC_PTR);    // Pointer to a mutable basic block count value
-        assert(iconFlags != GTF_ICON_GLOBAL_PTR); // Pointer to mutable data from the VM state
+        assert(GenTree::HandleKindDataIsInvariant(iconFlags));
 
         // This indirection also is invariant.
         indirFlags |= GTF_IND_INVARIANT;
@@ -10814,6 +10812,27 @@ void GenTree::SetIndirExceptionFlags(Compiler* comp)
     }
 }
 
+//------------------------------------------------------------------------------
+// HandleKindDataIsInvariant: Returns true if the data referred to by a handle
+// address is guaranteed to be invariant. Note that GTF_ICON_FTN_ADDR handles may
+// or may not point to invariant data.
+//
+// Arguments:
+//    flags - GenTree flags for handle.
+//
+/* static */
+bool GenTree::HandleKindDataIsInvariant(GenTreeFlags flags)
+{
+    GenTreeFlags handleKind = flags & GTF_ICON_HDL_MASK;
+    assert(handleKind != GTF_EMPTY);
+
+    // All handle types are assumed invariant except those specifically listed here.
+
+    return (handleKind != GTF_ICON_STATIC_HDL) && // Pointer to a mutable class Static variable
+           (handleKind != GTF_ICON_BBC_PTR) &&    // Pointer to a mutable basic block count value
+           (handleKind != GTF_ICON_GLOBAL_PTR);   // Pointer to mutable data from the VM state
+}
+
 #ifdef DEBUG
 
 /* static */ int GenTree::gtDispFlags(GenTreeFlags flags, GenTreeDebugFlags debugFlags)

src/coreclr/jit/gentree.h

@@ -2249,6 +2249,7 @@ struct GenTree
     }
 
 #if defined(TARGET_XARCH) && defined(FEATURE_HW_INTRINSICS)
+
     bool IsEmbMaskOp()
     {
         return OperIsHWIntrinsic() && ((gtFlags & GTF_HW_EM_OP) != 0);
@@ -2263,6 +2264,8 @@ struct GenTree
 
 #endif // TARGET_XARCH && FEATURE_HW_INTRINSICS
 
+    static bool HandleKindDataIsInvariant(GenTreeFlags flags);
+
     bool IsCall() const
     {
         return OperGet() == GT_CALL;