[x86/Linux] Port ResolveWorkerAsmStub (#8557)

src/vm/i386/asmhelpers.S

@@ -1066,3 +1066,52 @@ DYNAMICHELPER DynamicHelperFrameFlags_ObjectArg, _Obj
 DYNAMICHELPER (DynamicHelperFrameFlags_ObjectArg | DynamicHelperFrameFlags_ObjectArg2), _ObjObj
 
 #endif // FEATURE_READYTORUN
+
+NESTED_ENTRY ResolveWorkerAsmStub, _TEXT, NoHandler
+ //
+ // The stub arguments are where we want to setup the TransitionBlock. We will
+ // setup the TransitionBlock later once we can trash them
+ //
+ // push ebp-frame
+ // push ebp
+ // mov ebp,esp
+
+ // save CalleeSavedRegisters
+ // push ebx
+
+ push esi
+ push edi
+
+ // push ArgumentRegisters
+ push ecx
+ push edx
+
+ mov esi, esp
+
+ push [esi + 4*4] // dispatch token
+ push [esi + 5*4] // siteAddrForRegisterIndirect
+ push esi // pTransitionBlock
+
+ // Setup up proper EBP frame now that the stub arguments can be trashed
+ mov [esi + 4*4],ebx
+ mov [esi + 5*4],ebp
+ lea ebp, [esi + 5*4]
+
+ // Make the call
+ call C_FUNC(VSD_ResolveWorker)
+
+ // From here on, mustn't trash eax
+
+ // pop ArgumentRegisters
+ pop edx
+ pop ecx
+
+ // pop CalleeSavedRegisters
+ pop edi
+ pop esi
+ pop ebx
+ pop ebp
+
+ // Now jump to the target
+ jmp eax // continue on into the method
+NESTED_END ResolveWorkerAsmStub, _TEXT

src/vm/i386/unixstubs.cpp

@@ -80,11 +80,6 @@ EXTERN_C VOID ResolveWorkerChainLookupAsmStub()
  PORTABILITY_ASSERT("ResolveWorkerChainLookupAsmStub");
 }
 
-EXTERN_C VOID ResolveWorkerAsmStub()
-{
- PORTABILITY_ASSERT("ResolveWorkerAsmStub");
-}
-
 EXTERN_C VOID BackPatchWorkerAsmStub()
 {
  PORTABILITY_ASSERT("BackPatchWorkerAsmStub");