[ios-clr] Throw descriptive error when a stripped IL body is needed at runtime

src/coreclr/dlls/mscorrc/mscorrc.rc

@@ -606,6 +606,7 @@ BEGIN
         BFA_INVALID_TOKEN_IN_MANIFESTRES        "Invalid token saved in ManifestResource."
         BFA_EMPTY_ASSEMDEF_NAME                 "Empty assembly simple name."
         BFA_BAD_IL                              "Bad IL format."
+        BFA_STRIPPED_IL_BODY                    "A method body required at runtime was stripped from the ReadyToRun image and this runtime has no JIT to compile it."
         BFA_CLASSLOAD_VALUETYPEMISMATCH         "Could not load type '%1' from assembly '%2' due to value type mismatch."
         BFA_METHODDECL_NOT_A_METHODDEF          "Method declaration is not a methoddef."
         BFA_DUPLICATE_DELEGATE_METHOD           "Duplicate definition for runtime implemented delegate method."

src/coreclr/dlls/mscorrc/resource.h

@@ -462,6 +462,7 @@
 #define IDS_EE_INTEROP_STUB_CA_NO_ACCESS_TO_STUB_METHOD             0x2111
 #endif
 
+#define BFA_STRIPPED_IL_BODY                    0x2112
 #define BFA_REFERENCE_ASSEMBLY                  0x2113
 
 #define IDS_E_FIELDACCESS                       0x2114

src/coreclr/vm/prestub.cpp

@@ -18,6 +18,7 @@
 #include "comdelegate.h"
 #include "dbginterface.h"
 #include "stubgen.h"
+#include "openum.h"
 #include "eventtrace.h"
 #include "array.h"
 #include "ecall.h"
@@ -703,6 +704,16 @@ namespace
         if (status == COR_ILMETHOD_DECODER::FORMAT_ERROR)
             COMPlusThrowHR(COR_E_BADIMAGEFORMAT, BFA_BAD_IL);
 
+        Module* pModule = pMD->GetModule();
+        if (pModule->IsReadyToRun()
+            && pModule->GetReadyToRunInfo()->HasStrippedILBodies()
+            && pHeader->GetCodeSize() == 2
+            && pHeader->Code[0] == CEE_LDNULL
+            && pHeader->Code[1] == CEE_THROW)
+        {
+            COMPlusThrowHR(COR_E_BADIMAGEFORMAT, BFA_STRIPPED_IL_BODY);
+        }
+
         return pHeader;
     }