JIT: optimize calls on boxed objects

For calls with boxed this objects, invoke the unboxed entry point if available
and modify the box to copy the original value or struct to a local. Pass the
address of this local as the first argument to the unboxed entry point.

Defer for cases where the unboxed entry point requires an extra type parameter.

This may enable subsequent inlining of the method, and if the method has other
boxed parameters, may enable undoing those boxes as well.

The jit is not yet as proficient at eliminating the struct copies, but they
are present with or without this change, and some may even be required when the
methods mutate the fields of `this`.

Closes #14213.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/zap/zapinfo.cpp b/src/zap/zapinfo.cpp
index 4007f678ae..f0e9d9e8c4 100644
--- a/src/zap/zapinfo.cpp
+++ b/src/zap/zapinfo.cpp
@@ -3708,12 +3708,18 @@ void ZapInfo::getMethodVTableOffset(CORINFO_METHOD_HANDLE method,
 CORINFO_METHOD_HANDLE ZapInfo::resolveVirtualMethod(
         CORINFO_METHOD_HANDLE virtualMethod,
         CORINFO_CLASS_HANDLE implementingClass,
-        CORINFO_CONTEXT_HANDLE ownerType
-        )
+        CORINFO_CONTEXT_HANDLE ownerType)
 {
     return m_pEEJitInfo->resolveVirtualMethod(virtualMethod, implementingClass, ownerType);
 }
 
+CORINFO_METHOD_HANDLE ZapInfo::getUnboxedEntry(
+    CORINFO_METHOD_HANDLE ftn,
+    bool* requiresInstMethodTableArg)
+{
+    return m_pEEJitInfo->getUnboxedEntry(ftn, requiresInstMethodTableArg);
+}
+
 CORINFO_CLASS_HANDLE ZapInfo::getDefaultEqualityComparerClass(
     CORINFO_CLASS_HANDLE elemType)
 {