[MC] Replace HasAggressiveSymbolFolding with SetDirectiveSuppressesReloc. NFC

The variable and its comment could lead to confusion (AMDGPU
unnecessarily set it).

Author: MaskRay

llvm/include/llvm/MC/MCAsmInfo.h

@@ -348,21 +348,6 @@ class MCAsmInfo {
   ///   .long a
   bool SetDirectiveSuppressesReloc = false;
 
-  /// False if the assembler requires that we use
-  /// \code
-  ///   Lc = a - b
-  ///   .long Lc
-  /// \endcode
-  //
-  /// instead of
-  //
-  /// \code
-  ///   .long a - b
-  /// \endcode
-  ///
-  ///  Defaults to true.
-  bool HasAggressiveSymbolFolding = true;
-
   /// True is .comm's and .lcomms optional alignment is to be specified in bytes
   /// instead of log2(n).  Defaults to true.
   bool COMMDirectiveAlignmentIsInBytes = true;
@@ -722,8 +707,6 @@ class MCAsmInfo {
     return SetDirectiveSuppressesReloc;
   }
 
-  bool hasAggressiveSymbolFolding() const { return HasAggressiveSymbolFolding; }
-
   bool getCOMMDirectiveAlignmentIsInBytes() const {
     return COMMDirectiveAlignmentIsInBytes;
   }

llvm/lib/MC/MCAsmInfoDarwin.cpp

@@ -76,9 +76,6 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
   HasMachoZeroFillDirective = true;  // Uses .zerofill
   HasMachoTBSSDirective = true; // Uses .tbss
 
-  // FIXME: Change this once MC is the system assembler.
-  HasAggressiveSymbolFolding = false;
-
   HiddenVisibilityAttr = MCSA_PrivateExtern;
   HiddenDeclarationVisibilityAttr = MCSA_Invalid;
 

llvm/lib/MC/MCDwarf.cpp

@@ -320,9 +320,10 @@ MCDwarfLineTableHeader::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
 static const MCExpr *forceExpAbs(MCStreamer &OS, const MCExpr* Expr) {
   MCContext &Context = OS.getContext();
   assert(!isa<MCSymbolRefExpr>(Expr));
-  if (Context.getAsmInfo()->hasAggressiveSymbolFolding())
+  if (!Context.getAsmInfo()->doesSetDirectiveSuppressReloc())
     return Expr;
 
+  // On Mach-O, try to avoid a relocation by using a set directive.
   MCSymbol *ABS = Context.createTempSymbol();
   OS.emitAssignment(ABS, Expr);
   return MCSymbolRefExpr::create(ABS, Context);

llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCAsmInfo.cpp

@@ -34,7 +34,6 @@ AMDGPUMCAsmInfo::AMDGPUMCAsmInfo(const Triple &TT,
   UsesELFSectionDirectiveForBSS = true;
 
   //===--- Global Variable Emission Directives --------------------------===//
-  HasAggressiveSymbolFolding = true;
   COMMDirectiveAlignmentIsInBytes = false;
   HasNoDeadStrip = true;
   //===--- Dwarf Emission Directives -----------------------------------===//