Deal with cross-bitness compilation warnings Pt.2 (#19781)

* Disable ASMCONSTANTS_C_ASSERT in cross-bitness scenario in src/vm/ceeload.cpp

* Adjust MAXFIELDMARSHALERSIZE for cross-bitness scenario in src/vm/arm/cgencpu.h

* Make ALLOC_ALIGN_CONSTANT host specific in src/inc/stdmacros.h

* Make PRECODE_ALIGNMENT host specific in src/vm/arm/cgencpu.h

* Disable unreachable code in src/vm/arm/stubs.cpp

* Adjust CorDBIPC_BUFFER_SIZE for cross-bitness scenario in src/debug/inc/dbgipcevents.h

* Disable warning C4359 in src/vm/arm/cgencpu.h

* Deal with warning C4267: 'initializing': conversion from 'size_t' to 'int' in src/vm/stublink.cpp

* Deal with warning C4267: 'initializing': conversion from 'size_t' to 'int' in src/vm/callingconvention.h

* Disable unreachable REGDISPLAY constructor in src/inc/regdisp.h

8 files changed, 37 insertions, 13 deletions

diff --git a/src/debug/inc/dbgipcevents.h b/src/debug/inc/dbgipcevents.h
index b91bb5b549..653ec0d202 100644
--- a/src/debug/inc/dbgipcevents.h
+++ b/src/debug/inc/dbgipcevents.h
@@ -179,7 +179,11 @@ struct MSLAYOUT DebuggerIPCRuntimeOffsets
 // aren't any embedded buffers in the DebuggerIPCControlBlock).
 
 #if defined(DBG_TARGET_X86) || defined(DBG_TARGET_ARM)
+#ifdef _WIN64
+#define CorDBIPC_BUFFER_SIZE (2096)
+#else
 #define CorDBIPC_BUFFER_SIZE (2088) // hand tuned to ensure that ipc block in IPCHeader.h fits in 1 page.
+#endif
 #else  // !_TARGET_X86_ && !_TARGET_ARM_
 // This is the size of a DebuggerIPCEvent.  You will hit an assert in Cordb::Initialize() (DI\process.cpp)
 // if this is not defined correctly.  AMD64 actually has a page size of 0x1000, not 0x2000.
diff --git a/src/inc/regdisp.h b/src/inc/regdisp.h
index 06ceaf24a6..7875edf653 100644
--- a/src/inc/regdisp.h
+++ b/src/inc/regdisp.h
@@ -250,7 +250,7 @@ struct REGDISPLAY : public REGDISPLAY_BASE {
     ArmVolatileContextPointer     volatileCurrContextPointers;
 
     DWORD *  pPC;                // processor neutral name
-
+#ifndef CROSSGEN_COMPILE
     REGDISPLAY()
     {
         // Initialize regdisplay
@@ -259,6 +259,10 @@ struct REGDISPLAY : public REGDISPLAY_BASE {
         // Setup the pointer to ControlPC field
         pPC = &ControlPC;
     }
+#else
+private:
+    REGDISPLAY();
+#endif
 };
 
 // This function tells us if the given stack pointer is in one of the frames of the functions called by the given frame
diff --git a/src/inc/stdmacros.h b/src/inc/stdmacros.h
index d60abf56f5..6a7f286443 100644
--- a/src/inc/stdmacros.h
+++ b/src/inc/stdmacros.h
@@ -138,7 +138,7 @@
 
 
 #ifndef ALLOC_ALIGN_CONSTANT
-#define ALLOC_ALIGN_CONSTANT ((1<<LOG2_PTRSIZE)-1)
+#define ALLOC_ALIGN_CONSTANT (sizeof(void*)-1)
 #endif
 
 
diff --git a/src/vm/arm/cgencpu.h b/src/vm/arm/cgencpu.h
index 745626bd40..62891170c4 100644
--- a/src/vm/arm/cgencpu.h
+++ b/src/vm/arm/cgencpu.h
@@ -102,7 +102,11 @@ EXTERN_C void setFPReturn(int fpSize, INT64 retVal);
 // as large as the largest FieldMarshaler subclass. This requirement
 // is guarded by an assert.
 //=======================================================================
+#ifdef _WIN64
+#define MAXFIELDMARSHALERSIZE               40
+#else
 #define MAXFIELDMARSHALERSIZE               24
+#endif
 
 //**********************************************************************
 // Parameter size
@@ -985,6 +989,11 @@ inline BOOL IsUnmanagedValueTypeReturnedByRef(UINT sizeofvaluetype)
     return (sizeofvaluetype > 4);
 }
 
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable:4359) // Prevent "warning C4359: 'UMEntryThunkCode': Alignment specifier is less than actual alignment (8), and will be ignored." in crossbitness scenario
+#endif // _MSC_VER
+
 struct DECLSPEC_ALIGN(4) UMEntryThunkCode
 {
     WORD        m_code[4];
@@ -1010,6 +1019,10 @@ struct DECLSPEC_ALIGN(4) UMEntryThunkCode
     }
 };
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif // _MSC_VER
+
 struct HijackArgs
 {
     union
@@ -1082,7 +1095,7 @@ inline BOOL ClrFlushInstructionCache(LPCVOID pCodeAddr, size_t sizeOfCode)
 
 EXTERN_C VOID STDCALL PrecodeFixupThunk();
 
-#define PRECODE_ALIGNMENT           CODE_SIZE_ALIGN
+#define PRECODE_ALIGNMENT           sizeof(void*)
 #define SIZEOF_PRECODE_BASE         CODE_SIZE_ALIGN
 #define OFFSETOF_PRECODE_TYPE       0
 
diff --git a/src/vm/arm/stubs.cpp b/src/vm/arm/stubs.cpp
index bd3ad515c9..d2ee3b7c3e 100644
--- a/src/vm/arm/stubs.cpp
+++ b/src/vm/arm/stubs.cpp
@@ -1678,6 +1678,8 @@ VOID StubLinkerCPU::EmitShuffleThunk(ShuffleEntry *pShuffleEntryArray)
     ThumbEmitEpilog();
 }
 
+#ifndef CROSSGEN_COMPILE
+
 void StubLinkerCPU::ThumbEmitCallManagedMethod(MethodDesc *pMD, bool fTailcall)
 {
     bool isRelative = MethodTable::VTableIndir2_t::isRelative
@@ -1747,7 +1749,6 @@ void StubLinkerCPU::ThumbEmitCallManagedMethod(MethodDesc *pMD, bool fTailcall)
     }
 }
 
-#ifndef CROSSGEN_COMPILE
 // Common code used to generate either an instantiating method stub or an unboxing stub (in the case where the
 // unboxing stub also needs to provide a generic instantiation parameter). The stub needs to add the
 // instantiation parameter provided in pHiddenArg and re-arrange the rest of the incoming arguments as a
@@ -2368,7 +2369,6 @@ void TailCallFrame::InitFromContext(T_CONTEXT * pContext)
 }
 
 #endif // !DACCESS_COMPILE
-#endif // !CROSSGEN_COMPILE
 
 void FaultingExceptionFrame::UpdateRegDisplay(const PREGDISPLAY pRD) 
 { 
@@ -2527,7 +2527,8 @@ void HijackFrame::UpdateRegDisplay(const PREGDISPLAY pRD)
 
      SyncRegDisplayToCurrentContext(pRD);
 }
-#endif
+#endif // FEATURE_HIJACK
+#endif // !CROSSGEN_COMPILE
 
 class UMEntryThunk * UMEntryThunk::Decode(void *pCallback)
 {
diff --git a/src/vm/callingconvention.h b/src/vm/callingconvention.h
index a653d8570f..c219d70e8b 100644
--- a/src/vm/callingconvention.h
+++ b/src/vm/callingconvention.h
@@ -1209,7 +1209,7 @@ int ArgIteratorTemplate<ARGITERATOR_BASE>::GetNextOffset()
 
         // Doubles or HFAs containing doubles need the stack aligned appropriately.
         if (fRequiresAlign64Bit)
-            m_idxStack = ALIGN_UP(m_idxStack, 2);
+            m_idxStack = (int)ALIGN_UP(m_idxStack, 2);
 
         // Indicate the stack location of the argument to the caller.
         int argOfs = TransitionBlock::GetOffsetOfArgs() + m_idxStack * 4;
@@ -1231,7 +1231,7 @@ int ArgIteratorTemplate<ARGITERATOR_BASE>::GetNextOffset()
         {
             // The argument requires 64-bit alignment. Align either the next general argument register if
             // we have any left.  See step C.3 in the algorithm in the ABI spec.       
-            m_idxGenReg = ALIGN_UP(m_idxGenReg, 2);
+            m_idxGenReg = (int)ALIGN_UP(m_idxGenReg, 2);
         }
 
         int argOfs = TransitionBlock::GetOffsetOfArgumentRegisters() + m_idxGenReg * 4;
@@ -1262,7 +1262,7 @@ int ArgIteratorTemplate<ARGITERATOR_BASE>::GetNextOffset()
     {
         // The argument requires 64-bit alignment. If it is going to be passed on the stack, align
         // the next stack slot.  See step C.6 in the algorithm in the ABI spec.  
-        m_idxStack = ALIGN_UP(m_idxStack, 2);
+        m_idxStack = (int)ALIGN_UP(m_idxStack, 2);
     }
 
     int argOfs = TransitionBlock::GetOffsetOfArgs() + m_idxStack * 4;
diff --git a/src/vm/ceeload.cpp b/src/vm/ceeload.cpp
index cd9e485af7..b3d2d59cb3 100644
--- a/src/vm/ceeload.cpp
+++ b/src/vm/ceeload.cpp
@@ -14220,8 +14220,10 @@ void Module::ExpandAll()
 #include "clrvarargs.h" /* for VARARG C_ASSERTs in asmconstants.h */
 class CheckAsmOffsets
 {
+#ifndef CROSSBITNESS_COMPILE
 #define ASMCONSTANTS_C_ASSERT(cond) static_assert(cond, #cond);
 #include "asmconstants.h"
+#endif // CROSSBITNESS_COMPILE
 };
 
 //-------------------------------------------------------------------------------
diff --git a/src/vm/stublink.cpp b/src/vm/stublink.cpp
index d9715b7630..98e5b132f1 100644
--- a/src/vm/stublink.cpp
+++ b/src/vm/stublink.cpp
@@ -1624,7 +1624,7 @@ bool StubLinker::EmitUnwindInfo(Stub* pStub, int globalsize, LoaderHeap* pHeap)
         *pUnwindCodes++ = (BYTE)0xFF; // end
     }
 
-    int epilogUnwindCodeIndex = 0;
+    ptrdiff_t epilogUnwindCodeIndex = 0;
 
     //epilog differs from prolog
     if(m_cbStackFrame >= 4096)
@@ -1659,7 +1659,7 @@ bool StubLinker::EmitUnwindInfo(Stub* pStub, int globalsize, LoaderHeap* pHeap)
     }
 
     // Number of 32-bit unwind codes
-    int codeWordsCount = (ALIGN_UP((size_t)pUnwindCodes, sizeof(void*)) - (size_t)pUnwindInfo - sizeof(DWORD))/4;
+    size_t codeWordsCount = (ALIGN_UP((size_t)pUnwindCodes, sizeof(void*)) - (size_t)pUnwindInfo - sizeof(DWORD))/4;
 
     _ASSERTE(epilogUnwindCodeIndex < 32);
 
@@ -1669,8 +1669,8 @@ bool StubLinker::EmitUnwindInfo(Stub* pStub, int globalsize, LoaderHeap* pHeap)
     *(DWORD *)pUnwindInfo = 
         ((functionLength) / 2) |
         (1 << 21) |
-        (epilogUnwindCodeIndex << 23)|
-        (codeWordsCount << 28);  
+        ((int)epilogUnwindCodeIndex << 23)|
+        ((int)codeWordsCount << 28);
 
 #elif defined(_TARGET_ARM64_)
     if (!m_fProlog)