MCExpr: Remove VK_None

`enum VariantKind` is deprecated. Targets are encouraged to use their
own relocation specifier constants. MCSymbolRefExpr::create callers with
a VK_None argument should switch to the overload with a VariantKind
parameter.

Author: MaskRay

llvm/include/llvm/MC/MCExpr.h

@@ -196,9 +196,7 @@ class MCSymbolRefExpr : public MCExpr {
   // expressions with @). MCTargetExpr, as used by AArch64 and RISC-V, offers a
   // cleaner approach.
   enum VariantKind : uint16_t {
-    VK_None,
-
-    VK_SECREL,
+    VK_SECREL = 1,
     VK_WEAKREF, // The link between the symbols in .weakref foo, bar
 
     VK_COFF_IMGREL32, // symbol@imgrel (image-relative)
@@ -219,7 +217,7 @@ class MCSymbolRefExpr : public MCExpr {
 
   static const MCSymbolRefExpr *create(const MCSymbol *Symbol, MCContext &Ctx,
                                        SMLoc Loc = SMLoc()) {
-    return MCSymbolRefExpr::create(Symbol, VK_None, Ctx, Loc);
+    return MCSymbolRefExpr::create(Symbol, 0, Ctx, Loc);
   }
 
   LLVM_ABI static const MCSymbolRefExpr *create(const MCSymbol *Symbol,

llvm/lib/CodeGen/AsmPrinter/WinException.cpp

@@ -308,10 +308,8 @@ void WinException::endFuncletImpl() {
 const MCExpr *WinException::create32bitRef(const MCSymbol *Value) {
   if (!Value)
     return MCConstantExpr::create(0, Asm->OutContext);
-  return MCSymbolRefExpr::create(Value, useImageRel32
-                                            ? MCSymbolRefExpr::VK_COFF_IMGREL32
-                                            : MCSymbolRefExpr::VK_None,
-                                 Asm->OutContext);
+  auto Spec = useImageRel32 ? uint16_t(MCSymbolRefExpr::VK_COFF_IMGREL32) : 0;
+  return MCSymbolRefExpr::create(Value, Spec, Asm->OutContext);
 }
 
 const MCExpr *WinException::create32bitRef(const GlobalValue *GV) {