MCAsmInfo: Replace some Mach-O specific check with isMachO(). NFC

`HasMachO*` might lure contributors to add other object file format
propery when it is not really necessary.

Author: MaskRay

llvm/include/llvm/MC/MCAsmInfo.h

@@ -85,14 +85,6 @@ class MCAsmInfo {
   /// Default is false.
   bool HasSubsectionsViaSymbols = false;
 
-  /// True if this is a MachO target that supports the macho-specific .zerofill
-  /// directive for emitting BSS Symbols.  Default is false.
-  bool HasMachoZeroFillDirective = false;
-
-  /// True if this is a MachO target that supports the macho-specific .tbss
-  /// directive for emitting thread local BSS Symbols.  Default is false.
-  bool HasMachoTBSSDirective = false;
-
   /// True if this is a non-GNU COFF target. The COFF port of the GNU linker
   /// doesn't handle associative comdats in the way that we would like to use
   /// them.
@@ -401,10 +393,6 @@ class MCAsmInfo {
   /// undefined symbol.  Defaults to nullptr.
   const char *WeakRefDirective = nullptr;
 
-  /// True if we have a directive to declare a global as being a weak defined
-  /// symbol.  Defaults to false.
-  bool HasWeakDefDirective = false;
-
   /// True if we have a directive to declare a global as being a weak defined
   /// symbol that can be hidden (unexported).  Defaults to false.
   bool HasWeakDefCanBeHiddenDirective = false;
@@ -603,8 +591,7 @@ class MCAsmInfo {
 
   // Accessors.
 
-  bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
-  bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
+  bool isMachO() const { return HasSubsectionsViaSymbols; }
   bool hasCOFFAssociativeComdats() const { return HasCOFFAssociativeComdats; }
   bool hasCOFFComdatConstants() const { return HasCOFFComdatConstants; }
   bool hasVisibilityOnlyWithLinkage() const {
@@ -730,7 +717,6 @@ class MCAsmInfo {
   bool hasAltEntry() const { return HasAltEntry; }
   const char *getWeakDirective() const { return WeakDirective; }
   const char *getWeakRefDirective() const { return WeakRefDirective; }
-  bool hasWeakDefDirective() const { return HasWeakDefDirective; }
 
   bool hasWeakDefCanBeHiddenDirective() const {
     return HasWeakDefCanBeHiddenDirective;

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -636,7 +636,7 @@ void AsmPrinter::emitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
   case GlobalValue::LinkOnceODRLinkage:
   case GlobalValue::WeakAnyLinkage:
   case GlobalValue::WeakODRLinkage:
-    if (MAI->hasWeakDefDirective()) {
+    if (MAI->isMachO()) {
       // .globl _foo
       OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global);
 
@@ -779,8 +779,7 @@ void AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
 
   // If we have a bss global going to a section that supports the
   // zerofill directive, do so here.
-  if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
-      TheSection->isVirtualSection()) {
+  if (GVKind.isBSS() && MAI->isMachO() && TheSection->isVirtualSection()) {
     if (Size == 0)
       Size = 1; // zerofill of 0 bytes is undefined.
     emitLinkage(GV, GVSym);
@@ -825,7 +824,7 @@ void AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
   // TLOF class.  This will also make it more obvious that stuff like
   // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
   // specific code.
-  if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
+  if (GVKind.isThreadLocal() && MAI->isMachO()) {
     // Emit the .tbss symbol
     MCSymbol *MangSym =
         OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));

llvm/lib/MC/MCAsmInfoDarwin.cpp

@@ -69,12 +69,9 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
   InlineAsmEnd = " InlineAsm End";
 
   // Directives:
-  HasWeakDefDirective = true;
   HasWeakDefCanBeHiddenDirective = true;
   WeakRefDirective = "\t.weak_reference ";
   ZeroDirective = "\t.space\t";  // ".space N" emits N zeros.
-  HasMachoZeroFillDirective = true;  // Uses .zerofill
-  HasMachoTBSSDirective = true; // Uses .tbss
 
   HiddenVisibilityAttr = MCSA_PrivateExtern;
   HiddenDeclarationVisibilityAttr = MCSA_Invalid;