Add IsDevirtualizationCandidate

dotnet · Feb 18, 2025 · ba26707 · ba26707
1 parent 8a79637
commit ba26707
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Showing 4 changed files with 48 additions and 6 deletions.
diff --git a/src/coreclr/jit/fginline.cpp b/src/coreclr/jit/fginline.cpp
@@ -573,7 +573,7 @@ class SubstitutePlaceholdersAndDevirtualizeWalker : public GenTreeVisitor<Substi
         if (tree->OperGet() == GT_CALL)
         {
             GenTreeCall* call          = tree->AsCall();
-            bool         tryLateDevirt = call->IsVirtual() && (call->gtCallType == CT_USER_FUNC);
+            bool         tryLateDevirt = call->IsDevirtualizationCandidate(m_compiler);
 
 #ifdef DEBUG
             tryLateDevirt = tryLateDevirt && (JitConfig.JitEnableLateDevirtualization() == 1);
@@ -610,7 +610,7 @@ class SubstitutePlaceholdersAndDevirtualizeWalker : public GenTreeVisitor<Substi
                 m_compiler->impDevirtualizeCall(call, nullptr, &method, &methodFlags, &contextInput, &context,
                                                 isLateDevirtualization, explicitTailCall);
 
-                if (!call->IsVirtual())
+                if (!call->IsDevirtualizationCandidate(m_compiler))
                 {
                     assert(context != nullptr);
                     CORINFO_CALL_INFO callInfo = {};

diff --git a/src/coreclr/jit/gentree.cpp b/src/coreclr/jit/gentree.cpp
@@ -2417,6 +2417,44 @@ int GenTreeCall::GetNonStandardAddedArgCount(Compiler* compiler) const
     return 0;
 }
 
+//-------------------------------------------------------------------------
+// IsDevirtualizationCandidate: Determine if this GT_CALL node is a devirtualization candidate.
+//                              A call will be unmarked from devirtualization candidate if it
+//                              is devirtualized.
+//
+// Arguments:
+//     compiler - the compiler instance so that we can call eeFindHelper
+//
+// Return Value:
+//     Returns true if this GT_CALL node is a devirtualization candidate.
+//
+bool GenTreeCall::IsDevirtualizationCandidate(Compiler* compiler) const
+{
+    return (IsVirtual() && gtCallType == CT_USER_FUNC) ||
+           (gtCallType == CT_INDIRECT && gtCallAddr->IsCall() &&
+            gtCallAddr->AsCall()->IsVirtualFunctionPointerLookup(compiler));
+}
+
+//-------------------------------------------------------------------------
+// IsVirtualFunctionPointerLookup: Determine if this GT_CALL node is a virtual function pointer lookup.
+//
+// Arguments:
+//     compiler - the compiler instance so that we can call eeFindHelper
+//
+// Return Value:
+//     Returns true if this GT_CALL node is a virtual function pointer lookup.
+//
+bool GenTreeCall::IsVirtualFunctionPointerLookup(Compiler* compiler) const
+{
+    return gtCallAddr->IsHelperCall(compiler, CORINFO_HELP_VIRTUAL_FUNC_PTR) ||
+           gtCallAddr->IsHelperCall(compiler, CORINFO_HELP_GVMLOOKUP_FOR_SLOT)
+#ifdef FEATURE_READYTORUN
+           || gtCallAddr->IsHelperCall(compiler, CORINFO_HELP_READYTORUN_VIRTUAL_FUNC_PTR) ||
+           gtCallAddr->IsHelperCall(compiler, CORINFO_HELP_READYTORUN_GENERIC_HANDLE)
+#endif // FEATURE_READYTORUN
+        ;
+}
+
 //-------------------------------------------------------------------------
 // IsHelperCall: Determine if this GT_CALL node is a specific helper call.
 //

diff --git a/src/coreclr/jit/gentree.h b/src/coreclr/jit/gentree.h
@@ -5331,6 +5331,10 @@ struct GenTreeCall final : public GenTree
     {
         return (gtFlags & GTF_CALL_VIRT_KIND_MASK) == GTF_CALL_VIRT_VTABLE;
     }
+
+    bool IsDevirtualizationCandidate(Compiler* compiler) const;
+    bool IsVirtualFunctionPointerLookup(Compiler* compiler) const;
+
     bool IsInlineCandidate() const
     {
         return (gtFlags & GTF_CALL_INLINE_CANDIDATE) != 0;

diff --git a/src/coreclr/jit/importercalls.cpp b/src/coreclr/jit/importercalls.cpp
@@ -949,7 +949,7 @@ var_types Compiler::impImportCall(OPCODE                  opcode,
     // See if we can devirt if we aren't probing.
     if (!probing && opts.OptimizationEnabled())
     {
-        if (call->AsCall()->IsVirtual())
+        if (call->AsCall()->IsDevirtualizationCandidate(this))
         {
             // only true object pointers can be virtual
             assert(call->AsCall()->gtArgs.HasThisPointer() &&
@@ -965,7 +965,7 @@ var_types Compiler::impImportCall(OPCODE                  opcode,
                                 // inlinees.
                                 rawILOffset);
 
-            const bool wasDevirtualized = !call->AsCall()->IsVirtual();
+            const bool wasDevirtualized = !call->AsCall()->IsDevirtualizationCandidate(this);
 
             if (wasDevirtualized)
             {
@@ -8020,9 +8020,9 @@ void Compiler::impDevirtualizeCall(GenTreeCall*            call,
     assert(methodFlags != nullptr);
     assert(pContextHandle != nullptr);
 
-    // This should be a virtual vtable or virtual stub call.
+    // This should be a devirtualization candidate.
     //
-    assert(call->IsVirtual());
+    assert(call->IsDevirtualizationCandidate(this));
     assert(opts.OptimizationEnabled());
 
 #if defined(DEBUG)