MCSymbol: Remove setUndefined

The name is misleading, as setting Fragment to nullptr does not
necessarily make it undefined - common and equated symbols have
a nullptr fragment as well.

Author: MaskRay

bolt/lib/Core/BinaryContext.cpp

@@ -2517,7 +2517,7 @@ BinaryContext::calculateEmittedSize(BinaryFunction &BF, bool FixBranches) {
   // Clean-up the effect of the code emission.
   for (const MCSymbol &Symbol : Assembler.symbols()) {
     MCSymbol *MutableSymbol = const_cast<MCSymbol *>(&Symbol);
-    MutableSymbol->setUndefined();
+    MutableSymbol->setFragment(nullptr);
     MutableSymbol->setIsRegistered(false);
   }
 

bolt/lib/Passes/BinaryPasses.cpp

@@ -662,7 +662,7 @@ Error CleanMCState::runOnFunctions(BinaryContext &BC) {
     if (S->isDefined()) {
       LLVM_DEBUG(dbgs() << "BOLT-DEBUG: Symbol \"" << S->getName()
                         << "\" is already defined\n");
-      const_cast<MCSymbol *>(S)->setUndefined();
+      const_cast<MCSymbol *>(S)->setFragment(nullptr);
     }
     if (S->isRegistered()) {
       LLVM_DEBUG(dbgs() << "BOLT-DEBUG: Symbol \"" << S->getName()

llvm/include/llvm/MC/MCSymbol.h

@@ -215,7 +215,7 @@ class MCSymbol {
         Value = nullptr;
         kind = Kind::Regular;
       }
-      setUndefined();
+      Fragment = nullptr;
       IsRedefinable = false;
     }
   }
@@ -259,9 +259,6 @@ class MCSymbol {
     Fragment = F;
   }
 
-  /// Mark the symbol as undefined.
-  void setUndefined() { Fragment = nullptr; }
-
   /// @}
   /// \name Variable Symbols
   /// @{

llvm/lib/MC/MCSymbol.cpp

@@ -53,7 +53,7 @@ void MCSymbol::setVariableValue(const MCExpr *Value) {
          "Cannot equate a common symbol");
   this->Value = Value;
   kind = Kind::Equated;
-  setUndefined();
+  Fragment = nullptr;
 }
 
 void MCSymbol::print(raw_ostream &OS, const MCAsmInfo *MAI) const {

llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp

@@ -220,7 +220,6 @@ static MCSymbolWasm *getOrCreateFunctionTableSymbol(MCContext &Ctx,
     Sym = static_cast<MCSymbolWasm *>(Ctx.getOrCreateSymbol(Name));
     Sym->setFunctionTable(Is64);
     // The default function table is synthesized by the linker.
-    Sym->setUndefined();
   }
   return Sym;
 }

llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp

@@ -113,7 +113,6 @@ MCSymbolWasm *WebAssembly::getOrCreateFunctionTableSymbol(
     Sym = static_cast<MCSymbolWasm *>(Ctx.getOrCreateSymbol(Name));
     Sym->setFunctionTable(is64);
     // The default function table is synthesized by the linker.
-    Sym->setUndefined();
   }
   // MVP object files can't have symtab entries for tables.
   if (!(Subtarget && Subtarget->hasCallIndirectOverlong()))