Mar 17, 2022 · Sep 24, 2021 · Feb 22, 2022 · Feb 22, 2022 · Feb 23, 2022 · Feb 24, 2022
diff --git a/src/coreclr/vm/jitinterface.cpp b/src/coreclr/vm/jitinterface.cpp
    // Resolve methodImpl.
    ftn = ftn->GetMethodTable()->MapMethodDeclToMethodImpl(ftn);

    if (!ftn->IsFCall() && ftn->MayHavePrecode() && ftn->GetPrecodeType() == PRECODE_FIXUP)
    if (!ftn->IsFCall() && ftn->IsVersionableWithPrecode() &&(ftn->GetPrecodeType() == PRECODE_FIXUP) && !ftn->IsPointingToStableNativeCode())
    {
        ret = ((FixupPrecode*)ftn->GetOrCreatePrecode())->GetTargetSlot();
        accessType = IAT_PVALUE;
    }
    else
    {
        ret = (void *)ftn->TryGetMultiCallableAddrOfCode(accessFlags);
    }

    // TryGetMultiCallableAddrOfCode returns NULL if indirect access is desired
    if (ret == NULL)
    {
        // should never get here for EnC methods or if interception via remoting stub is required
        _ASSERTE(!ftn->IsEnCMethod());
 // TryGetMultiCallableAddrOfCode returns NULL if indirect access is desired
 if (ret == NULL)
 {
 // should never get here for EnC methods or if interception via remoting stub is required
 _ASSERTE(!ftn->IsEnCMethod());

        ret = (void *)ftn->GetAddrOfSlot();
 ret = (void *)ftn->GetAddrOfSlot();

        accessType = IAT_PVALUE;
            accessType = IAT_PVALUE;
        }
    }


 #if defined(FEATURE_GDBJIT)
    CalledMethod * pCM = new CalledMethod(orig_ftn, ret, m_pCalledMethods);
    m_pCalledMethods = pCM;
        }
 #endif

        if (dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFINTERFACE ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFANY ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFARRAY ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFCLASS ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTANY ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTARRAY ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTINTERFACE ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTCLASS ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTCLASS_SPECIAL ||
            dynamicFtnNum == DYNAMIC_CORINFO_HELP_UNBOX)
        {
            Precode* pPrecode = Precode::GetPrecodeFromEntryPoint((PCODE)hlpDynamicFuncTable[dynamicFtnNum].pfnHelper);
            _ASSERTE(pPrecode->GetType() == PRECODE_FIXUP);
            *ppIndirection = ((FixupPrecode*)pPrecode)->GetTargetSlot();
            return NULL;
        }

        pfnHelper = hlpDynamicFuncTable[dynamicFtnNum].pfnHelper;

 #ifdef _PREFAST_
Original file line number	Diff line number	Diff line change
Expand Up		@@ -9006,28 +9006,27 @@ void CEEInfo::getFunctionEntryPoint(CORINFO_METHOD_HANDLE ftnHnd,
		// Resolve methodImpl.
		ftn = ftn->GetMethodTable()->MapMethodDeclToMethodImpl(ftn);

		if (!ftn->IsFCall() && ftn->MayHavePrecode() && ftn->GetPrecodeType() == PRECODE_FIXUP)
		if (!ftn->IsFCall() && ftn->IsVersionableWithPrecode() &&(ftn->GetPrecodeType() == PRECODE_FIXUP) && !ftn->IsPointingToStableNativeCode())
		{
		ret = ((FixupPrecode*)ftn->GetOrCreatePrecode())->GetTargetSlot();
		accessType = IAT_PVALUE;
		}
		else
		{
		ret = (void *)ftn->TryGetMultiCallableAddrOfCode(accessFlags);
		}

		// TryGetMultiCallableAddrOfCode returns NULL if indirect access is desired
		if (ret == NULL)
		{
		// should never get here for EnC methods or if interception via remoting stub is required
		_ASSERTE(!ftn->IsEnCMethod());
		// TryGetMultiCallableAddrOfCode returns NULL if indirect access is desired
		if (ret == NULL)
		{
		// should never get here for EnC methods or if interception via remoting stub is required
		_ASSERTE(!ftn->IsEnCMethod());

		ret = (void *)ftn->GetAddrOfSlot();
		ret = (void *)ftn->GetAddrOfSlot();

		accessType = IAT_PVALUE;
		accessType = IAT_PVALUE;
		}
		}


		#if defined(FEATURE_GDBJIT)
		CalledMethod * pCM = new CalledMethod(orig_ftn, ret, m_pCalledMethods);
		m_pCalledMethods = pCM;
Expand DownExpand Up		@@ -11134,6 +11133,23 @@ void* CEEJitInfo::getHelperFtn(CorInfoHelpFunc ftnNum, /* IN */
		}
		#endif

		if (dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFINTERFACE \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFANY \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFARRAY \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_ISINSTANCEOFCLASS \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTANY \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTARRAY \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTINTERFACE \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTCLASS \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_CHKCASTCLASS_SPECIAL \|\|
		dynamicFtnNum == DYNAMIC_CORINFO_HELP_UNBOX)
		{
		Precode* pPrecode = Precode::GetPrecodeFromEntryPoint((PCODE)hlpDynamicFuncTable[dynamicFtnNum].pfnHelper);
		_ASSERTE(pPrecode->GetType() == PRECODE_FIXUP);
		ppIndirection = ((FixupPrecode)pPrecode)->GetTargetSlot();
Copy link Member jkotasMar 3, 2022 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. What guarantees that we have the final code of the method by this point? If this is a valid optimization, we should be doing it when filling`hlpDynamicFuncTable`. Copy link MemberAuthor janvorliMar 3, 2022 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. We don't need to have the final code. This just passes the fixup precode indirection slot to the JIT. If we don't have the final code, the slot points to the fixup part of the slot. When we have the JITted code, the slot points to it. Without this optimization, JIT would jump to the beginning of the fixup stub and the indirect jump in there would jump through the slot. So we save one jump by this. I have found this using the performance repo microbenchmarks where the casting benchmarks were consistently slower with my change. With this fix, they are now consistently faster. Copy link MemberAuthor janvorliMar 3, 2022 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. We can modify the`hlpDynamicFuncTable` entry to be able to carry either the indirection or the target address and a flag indicating which one it is. I was going back and forth in my head whether to do that or do it the way I've ended up doing it. However, there is a`_AddrIsJITHelper` function on 32 bit Windows in the debugger controller code that compares addresses of all the helpers with an address that the debugger has stepped into to avoid the debugger stopping in unmanaged runtime code. While I believe we should not call this methods that code for prefix stubs (we should get TRACE_STUB tracetype), I need to double check that. I am talking about the case when the helper was not JITted yet and so the indirection would go to the middle of the fixup stub and the code there would not detect it was in a helper. Copy link Member jkotasMar 3, 2022 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. This just passes the fixup precode indirection slot to the JIT. If we don't have the final code, the slot points to the fixup part of the slot. Ah ok, I have missed that.
		return NULL;
		}

		pfnHelper = hlpDynamicFuncTable[dynamicFtnNum].pfnHelper;

		#ifdef _PREFAST_
Expand Down