Simplify making IL base JIT Helpers (#108349)

- Currently, for best performance, one needs to know to update a switch statement in jitinterface.cpp whenever a helper is moved to managed
- Instead, with this change, if the helper has a specified managed method implementation, that check will just work
- Also, if there is a native implementation, then the native implementation will take precedence. (This is to allow for helpers to have alternative assembly based implementations)
- NOTE, it is also possible to disable using an indirection, as that produces slightly smaller code, which is useful for helpers which are used only in cold code paths. This is done by using `DYNAMICJITHELPER_NOINDIRECT` to define the helper.

This should help fix a regression #108203 introduced with my recent work around generics lookups.

src/coreclr/inc/jithelpers.h

@@ -23,6 +23,12 @@
 #define DYNAMICJITHELPER(code,fn,binderId) JITHELPER(code,fn,binderId)
 #endif
 
+#ifndef DYNAMICJITHELPER_NOINDIRECT
+//I should try to call these methods via a non-indirect call, as those are typically smaller
+//and that is an improvement for these dynamic helpers.
+#define DYNAMICJITHELPER_NOINDIRECT(code,fn,binderId) DYNAMICJITHELPER(code,fn,binderId)
+#endif
+
 // pfnHelper is set to NULL if it is a stubbed helper.
 // It will be set in InitJITHelpers2
 
@@ -119,11 +125,11 @@
     DYNAMICJITHELPER(CORINFO_HELP_THROW,        IL_Throw,           METHOD__NIL)
     DYNAMICJITHELPER(CORINFO_HELP_RETHROW,      IL_Rethrow,         METHOD__NIL)
     JITHELPER(CORINFO_HELP_USER_BREAKPOINT,     JIT_UserBreakpoint, METHOD__NIL)
-    DYNAMICJITHELPER(CORINFO_HELP_RNGCHKFAIL,   NULL,               METHOD__THROWHELPERS__THROWINDEXOUTOFRANGEEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_OVERFLOW,     NULL,               METHOD__THROWHELPERS__THROWOVERFLOWEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_THROWDIVZERO, NULL,               METHOD__THROWHELPERS__THROWDIVIDEBYZEROEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_THROWNULLREF, NULL,               METHOD__THROWHELPERS__THROWNULLREFEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_VERIFICATION, NULL,               METHOD__THROWHELPERS__THROWVERIFICATIONEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_RNGCHKFAIL,   NULL,               METHOD__THROWHELPERS__THROWINDEXOUTOFRANGEEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_OVERFLOW,     NULL,               METHOD__THROWHELPERS__THROWOVERFLOWEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROWDIVZERO, NULL,               METHOD__THROWHELPERS__THROWDIVIDEBYZEROEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROWNULLREF, NULL,               METHOD__THROWHELPERS__THROWNULLREFEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_VERIFICATION, NULL,               METHOD__THROWHELPERS__THROWVERIFICATIONEXCEPTION)
     JITHELPER(CORINFO_HELP_FAIL_FAST,           JIT_FailFast,       METHOD__NIL)
     JITHELPER(CORINFO_HELP_METHOD_ACCESS_EXCEPTION,JIT_ThrowMethodAccessException, METHOD__NIL)
     JITHELPER(CORINFO_HELP_FIELD_ACCESS_EXCEPTION,JIT_ThrowFieldAccessException, METHOD__NIL)
@@ -285,13 +291,13 @@
     JITHELPER(CORINFO_HELP_LOOP_CLONE_CHOICE_ADDR, JIT_LoopCloneChoiceAddr, METHOD__NIL)
     JITHELPER(CORINFO_HELP_DEBUG_LOG_LOOP_CLONING, JIT_DebugLogLoopCloning, METHOD__NIL)
 
-    DYNAMICJITHELPER(CORINFO_HELP_THROW_ARGUMENTEXCEPTION,              NULL,   METHOD__THROWHELPERS__THROWARGUMENTEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_THROW_ARGUMENTOUTOFRANGEEXCEPTION,    NULL,   METHOD__THROWHELPERS__THROWARGUMENTOUTOFRANGEEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_THROW_NOT_IMPLEMENTED,                NULL,   METHOD__THROWHELPERS__THROWNOTIMPLEMENTEDEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_THROW_PLATFORM_NOT_SUPPORTED,         NULL,   METHOD__THROWHELPERS__THROWPLATFORMNOTSUPPORTEDEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_THROW_TYPE_NOT_SUPPORTED,             NULL,   METHOD__THROWHELPERS__THROWTYPENOTSUPPORTED)
-    DYNAMICJITHELPER(CORINFO_HELP_THROW_AMBIGUOUS_RESOLUTION_EXCEPTION, NULL,   METHOD__THROWHELPERS__THROWAMBIGUOUSRESOLUTIONEXCEPTION)
-    DYNAMICJITHELPER(CORINFO_HELP_THROW_ENTRYPOINT_NOT_FOUND_EXCEPTION, NULL,   METHOD__THROWHELPERS__THROWENTRYPOINTNOTFOUNDEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROW_ARGUMENTEXCEPTION,              NULL,   METHOD__THROWHELPERS__THROWARGUMENTEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROW_ARGUMENTOUTOFRANGEEXCEPTION,    NULL,   METHOD__THROWHELPERS__THROWARGUMENTOUTOFRANGEEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROW_NOT_IMPLEMENTED,                NULL,   METHOD__THROWHELPERS__THROWNOTIMPLEMENTEDEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROW_PLATFORM_NOT_SUPPORTED,         NULL,   METHOD__THROWHELPERS__THROWPLATFORMNOTSUPPORTEDEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROW_TYPE_NOT_SUPPORTED,             NULL,   METHOD__THROWHELPERS__THROWTYPENOTSUPPORTED)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROW_AMBIGUOUS_RESOLUTION_EXCEPTION, NULL,   METHOD__THROWHELPERS__THROWAMBIGUOUSRESOLUTIONEXCEPTION)
+    DYNAMICJITHELPER_NOINDIRECT(CORINFO_HELP_THROW_ENTRYPOINT_NOT_FOUND_EXCEPTION, NULL,   METHOD__THROWHELPERS__THROWENTRYPOINTNOTFOUNDEXCEPTION)
 
     JITHELPER(CORINFO_HELP_JIT_PINVOKE_BEGIN,         JIT_PInvokeBegin,     METHOD__NIL)
     JITHELPER(CORINFO_HELP_JIT_PINVOKE_END,           JIT_PInvokeEnd,       METHOD__NIL)
@@ -338,4 +344,4 @@
 #undef JITHELPER
 #undef DYNAMICJITHELPER
 #undef JITHELPER
-#undef DYNAMICJITHELPER
+#undef DYNAMICJITHELPER_NOINDIRECT

src/coreclr/jit/codegenarm64.cpp

@@ -5179,10 +5179,17 @@ void CodeGen::genEmitHelperCall(unsigned helper, int argSize, emitAttr retSize,
 
         callTarget = callTargetReg;
 
-        // adrp + add with relocations will be emitted
-        GetEmitter()->emitIns_R_AI(INS_adrp, EA_PTR_DSP_RELOC, callTarget,
-                                   (ssize_t)pAddr DEBUGARG((size_t)compiler->eeFindHelper(helper))
-                                       DEBUGARG(GTF_ICON_METHOD_HDL));
+        if (compiler->opts.compReloc)
+        {
+            // adrp + add with relocations will be emitted
+            GetEmitter()->emitIns_R_AI(INS_adrp, EA_PTR_DSP_RELOC, callTarget,
+                                       (ssize_t)pAddr DEBUGARG((size_t)compiler->eeFindHelper(helper))
+                                           DEBUGARG(GTF_ICON_METHOD_HDL));
+        }
+        else
+        {
+            instGen_Set_Reg_To_Imm(EA_PTRSIZE, callTarget, (ssize_t)addr);
+        }
         GetEmitter()->emitIns_R_R(INS_ldr, EA_PTRSIZE, callTarget, callTarget);
         callType = emitter::EC_INDIR_R;
     }

src/coreclr/vm/jithelpers.cpp

@@ -4441,7 +4441,7 @@ VMHELPDEF hlpDynamicFuncTable[DYNAMIC_CORINFO_HELP_COUNT] =
 static const BinderMethodID hlpDynamicToBinderMap[DYNAMIC_CORINFO_HELP_COUNT] =
 {
 #define JITHELPER(code, pfnHelper, binderId)
-#define DYNAMICJITHELPER(code, pfnHelper, binderId) (BinderMethodID)binderId,
+#define DYNAMICJITHELPER(code, pfnHelper, binderId) (pfnHelper != NULL) ? (BinderMethodID)METHOD__NIL : (BinderMethodID)binderId, // If pre-compiled code is provided for a jit helper, prefer that over the IL implementation
 #include "jithelpers.h"
 };
 
@@ -4504,6 +4504,34 @@ VMHELPDEF LoadDynamicJitHelper(DynamicCorInfoHelpFunc ftnNum, MethodDesc** metho
     return hlpDynamicFuncTable[ftnNum];
 }
 
+bool HasILBasedDynamicJitHelper(DynamicCorInfoHelpFunc ftnNum)
+{
+    STANDARD_VM_CONTRACT;
+
+    _ASSERTE(ftnNum < DYNAMIC_CORINFO_HELP_COUNT);
+
+    return (METHOD__NIL != hlpDynamicToBinderMap[ftnNum]);
+}
+
+bool IndirectionAllowedForJitHelper(CorInfoHelpFunc ftnNum)
+{
+    STANDARD_VM_CONTRACT;
+
+    _ASSERTE(ftnNum < CORINFO_HELP_COUNT);
+
+    if (
+#define DYNAMICJITHELPER(code,fn,binderId)
+#define JITHELPER(code,fn,binderId)
+#define DYNAMICJITHELPER_NOINDIRECT(code,fn,binderId) (code == ftnNum) ||
+#include "jithelpers.h"
+        false)
+    {
+        return false;
+    }
+
+    return true;
+}
+
 /*********************************************************************/
 // Initialize the part of the JIT helpers that require much of the
 // EE infrastructure to be in place.

src/coreclr/vm/jitinterface.cpp

@@ -10701,6 +10701,7 @@ void* CEEJitInfo::getHelperFtn(CorInfoHelpFunc    ftnNum,         /* IN  */
             _ASSERTE(ppIndirection != NULL);
             _ASSERTE(hlpDynamicFuncTable[dynamicFtnNum].pfnHelper != NULL); // Confirm the helper is non-null and doesn't require lazy loading.
             *ppIndirection = &hlpDynamicFuncTable[dynamicFtnNum].pfnHelper;
+            _ASSERTE(IndirectionAllowedForJitHelper(ftnNum));
             result = NULL;
             goto exit;
         }
@@ -10715,28 +10716,7 @@ void* CEEJitInfo::getHelperFtn(CorInfoHelpFunc    ftnNum,         /* IN  */
             goto exit;
         }
 
-        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 ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_ARRADDR_ST ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_LDELEMA_REF ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_MEMSET ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_MEMZERO ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_MEMCPY ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_BULK_WRITEBARRIER ||
-            IN_TARGET_32BIT(dynamicFtnNum == DYNAMIC_CORINFO_HELP_LMUL_OVF ||)
-            IN_TARGET_32BIT(dynamicFtnNum == DYNAMIC_CORINFO_HELP_ULMUL_OVF ||)
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_DBL2INT_OVF ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_DBL2LNG_OVF ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_DBL2UINT_OVF ||
-            dynamicFtnNum == DYNAMIC_CORINFO_HELP_DBL2ULNG_OVF)
+        if (HasILBasedDynamicJitHelper((DynamicCorInfoHelpFunc)dynamicFtnNum))
         {
             MethodDesc* helperMD = NULL;
             (void)LoadDynamicJitHelper((DynamicCorInfoHelpFunc)dynamicFtnNum, &helperMD);
@@ -10774,11 +10754,14 @@ void* CEEJitInfo::getHelperFtn(CorInfoHelpFunc    ftnNum,         /* IN  */
                 }
             }
 
-            Precode* pPrecode = helperMD->GetPrecode();
-            _ASSERTE(pPrecode->GetType() == PRECODE_FIXUP);
-            *ppIndirection = ((FixupPrecode*)pPrecode)->GetTargetSlot();
-            result = NULL;
-            goto exit;
+            if (IndirectionAllowedForJitHelper(ftnNum))
+            {
+                Precode* pPrecode = helperMD->GetPrecode();
+                _ASSERTE(pPrecode->GetType() == PRECODE_FIXUP);
+                *ppIndirection = ((FixupPrecode*)pPrecode)->GetTargetSlot();
+                result = NULL;
+                goto exit;
+            }
         }
 
         pfnHelper = LoadDynamicJitHelper((DynamicCorInfoHelpFunc)dynamicFtnNum).pfnHelper;

src/coreclr/vm/jitinterface.h

@@ -1028,6 +1028,8 @@ GARY_DECL(VMHELPDEF, hlpDynamicFuncTable, DYNAMIC_CORINFO_HELP_COUNT);
 void    _SetJitHelperFunction(DynamicCorInfoHelpFunc ftnNum, void * pFunc);
 
 VMHELPDEF LoadDynamicJitHelper(DynamicCorInfoHelpFunc ftnNum, MethodDesc** methodDesc = NULL);
+bool HasILBasedDynamicJitHelper(DynamicCorInfoHelpFunc ftnNum);
+bool IndirectionAllowedForJitHelper(CorInfoHelpFunc ftnNum);
 
 void *GenFastGetSharedStaticBase(bool bCheckCCtor);