[MC] Replace getSymA()->getSymbol() with getAddSym. NFC

We will replace the MCSymbolRefExpr member in MCValue with MCSymbol.
This change reduces dependence on MCSymbolRefExpr.

Author: MaskRay

llvm/lib/MC/MCAssembler.cpp

@@ -164,14 +164,11 @@ bool MCAssembler::evaluateFixup(const MCFixup &Fixup, const MCFragment *DF,
   bool IsPCRel = FixupFlags & MCFixupKindInfo::FKF_IsPCRel;
   bool IsResolved = false;
   if (IsPCRel) {
-    if (Target.getSubSym()) {
-      IsResolved = false;
-    } else if (!Target.getSymA()) {
+    if (Target.getSubSym() || !Target.getAddSym()) {
       IsResolved = false;
     } else {
-      const MCSymbolRefExpr *A = Target.getSymA();
-      const MCSymbol &SA = A->getSymbol();
-      if (A->getKind() != MCSymbolRefExpr::VK_None || SA.isUndefined()) {
+      auto &SA = *Target.getAddSym();
+      if (Target.getSymSpecifier() || SA.isUndefined()) {
         IsResolved = false;
       } else {
         IsResolved = (FixupFlags & MCFixupKindInfo::FKF_Constant) ||

llvm/lib/MC/MCExpr.cpp

@@ -578,7 +578,7 @@ bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
       break;
     case MCUnaryExpr::Minus:
       /// -(a - b + const) ==> (b - a - const)
-      if (Value.getSymA() && !Value.getSubSym())
+      if (Value.getAddSym() && !Value.getSubSym())
         return false;
 
       // The cast avoids undefined behavior if the constant is INT64_MIN.

llvm/lib/MC/MCObjectStreamer.cpp

@@ -676,8 +676,7 @@ MCObjectStreamer::emitRelocDirective(const MCExpr &Offset, StringRef Name,
     return std::make_pair(false,
                           std::string(".reloc offset is not representable"));
 
-  const MCSymbolRefExpr &SRE = cast<MCSymbolRefExpr>(*OffsetVal.getSymA());
-  const MCSymbol &Symbol = SRE.getSymbol();
+  const MCSymbol &Symbol = *OffsetVal.getAddSym();
   if (Symbol.isDefined()) {
     uint32_t SymbolOffset = 0;
     std::optional<std::pair<bool, std::string>> Error =
@@ -693,8 +692,7 @@ MCObjectStreamer::emitRelocDirective(const MCExpr &Offset, StringRef Name,
   }
 
   PendingFixups.emplace_back(
-      &SRE.getSymbol(), DF,
-      MCFixup::create(OffsetVal.getConstant(), Expr, Kind, Loc));
+      &Symbol, DF, MCFixup::create(OffsetVal.getConstant(), Expr, Kind, Loc));
   return std::nullopt;
 }
 

llvm/lib/MC/WasmObjectWriter.cpp

@@ -519,8 +519,7 @@ void WasmObjectWriter::recordRelocation(MCAssembler &Asm,
   }
 
   // We either rejected the fixup or folded B into C at this point.
-  const MCSymbolRefExpr *RefA = Target.getSymA();
-  const auto *SymA = cast<MCSymbolWasm>(&RefA->getSymbol());
+  const auto *SymA = cast<MCSymbolWasm>(Target.getAddSym());
 
   // The .init_array isn't translated as data, so don't do relocations in it.
   if (FixupSection.getName().starts_with(".init_array")) {
@@ -607,7 +606,7 @@ void WasmObjectWriter::recordRelocation(MCAssembler &Asm,
     SymA->setUsedInReloc();
   }
 
-  switch (RefA->getKind()) {
+  switch (Target.getSymSpecifier()) {
   case MCSymbolRefExpr::VK_GOT:
   case MCSymbolRefExpr::VK_WASM_GOT_TLS:
     SymA->setUsedInGOT();

llvm/lib/MC/WinCOFFObjectWriter.cpp

@@ -837,9 +837,9 @@ void WinCOFFWriter::recordRelocation(MCAssembler &Asm,
                                      const MCFragment *Fragment,
                                      const MCFixup &Fixup, MCValue Target,
                                      uint64_t &FixedValue) {
-  assert(Target.getSymA() && "Relocation must reference a symbol!");
+  assert(Target.getAddSym() && "Relocation must reference a symbol!");
 
-  const MCSymbol &A = Target.getSymA()->getSymbol();
+  const MCSymbol &A = *Target.getAddSym();
   if (!A.isRegistered()) {
     Asm.getContext().reportError(Fixup.getLoc(), Twine("symbol '") +
                                                      A.getName() +