[MC] Replace getSpecifier(Target.getSymA()) with Target.getSymSpecifier()

Add MCValue::getSymSpecifier as a workaround for targets that encode the
relocation specifier on SymA. This function asserts that SymA is not
null.

Author: MaskRay

llvm/include/llvm/MC/MCValue.h

@@ -67,6 +67,8 @@ class MCValue {
 
   // Get the relocation specifier from SymA. This is a workaround for targets
   // that do not use MCValue::Specifier.
+  uint16_t getSymSpecifier() const { return SymA->getSpecifier(); }
+  // Get the relocation specifier from SymA, or 0 when SymA is null.
   uint16_t getAccessVariant() const;
 
   static MCValue get(const MCSymbolRefExpr *SymA,

llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp

@@ -8224,7 +8224,7 @@ bool AArch64AsmParser::classifySymbolRef(const MCExpr *Expr,
     return false;
 
   if (Res.getSymA())
-    DarwinSpec = AArch64MCExpr::Specifier(Res.getSymA()->getKind());
+    DarwinSpec = AArch64MCExpr::Specifier(Res.getSymSpecifier());
   Addend = Res.getConstant();
 
   // It's some symbol reference + a constant addend, but really

llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp

@@ -117,9 +117,9 @@ unsigned AArch64ELFObjectWriter::getRelocType(MCContext &Ctx,
   bool IsNC = AArch64MCExpr::isNotChecked(RefKind);
 
   assert((!Target.getSymA() ||
-          getSpecifier(Target.getSymA()) == AArch64MCExpr::None ||
-          getSpecifier(Target.getSymA()) == AArch64MCExpr::VK_PLT ||
-          getSpecifier(Target.getSymA()) == AArch64MCExpr::VK_GOTPCREL) &&
+          Target.getSymSpecifier() == AArch64MCExpr::None ||
+          Target.getSymSpecifier() == AArch64MCExpr::VK_PLT ||
+          Target.getSymSpecifier() == AArch64MCExpr::VK_GOTPCREL) &&
          "Should only be expression-level modifiers here");
 
   switch (SymLoc) {

llvm/lib/Target/AArch64/MCTargetDesc/AArch64MachObjectWriter.cpp

@@ -221,7 +221,7 @@ void AArch64MachObjectWriter::recordRelocation(
     // Check for "_foo@got - .", which comes through here as:
     // Ltmp0:
     //    ... _foo@got - Ltmp0
-    if (getSpecifier(Target.getSymA()) == AArch64MCExpr::M_GOT &&
+    if (Target.getSymSpecifier() == AArch64MCExpr::M_GOT &&
         Asm.getSymbolOffset(*B) ==
             Asm.getFragmentOffset(*Fragment) + Fixup.getOffset()) {
       // SymB is the PC, so use a PC-rel pointer-to-GOT relocation.
@@ -232,7 +232,7 @@ void AArch64MachObjectWriter::recordRelocation(
       MRE.r_word1 = (IsPCRel << 24) | (Log2Size << 25) | (Type << 28);
       Writer->addRelocation(A_Base, Fragment->getParent(), MRE);
       return;
-    } else if (getSpecifier(Target.getSymA()) != AArch64MCExpr::None) {
+    } else if (Target.getSymSpecifier() != AArch64MCExpr::None) {
       // Otherwise, neither symbol can be modified.
       Asm.getContext().reportError(Fixup.getLoc(),
                                    "unsupported relocation of modified symbol");

llvm/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp

@@ -62,7 +62,7 @@ unsigned AArch64WinCOFFObjectWriter::getRelocType(
   }
 
   auto Modifier =
-      Target.isAbsolute() ? AArch64MCExpr::None : Target.getSymA()->getKind();
+      Target.isAbsolute() ? AArch64MCExpr::None : Target.getSymSpecifier();
   const MCExpr *Expr = Fixup.getValue();
 
   if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {

llvm/lib/Target/ARM/MCTargetDesc/ARMWinCOFFObjectWriter.cpp

@@ -44,10 +44,7 @@ unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
                                               const MCFixup &Fixup,
                                               bool IsCrossSection,
                                               const MCAsmBackend &MAB) const {
-  MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute()
-                                              ? MCSymbolRefExpr::VK_None
-                                              : Target.getSymA()->getKind();
-
+  auto Spec = Target.getAddSym() ? Target.getSymSpecifier() : 0;
   unsigned FixupKind = Fixup.getKind();
   if (IsCrossSection) {
     if (FixupKind != FK_Data_4) {
@@ -64,7 +61,7 @@ unsigned ARMWinCOFFObjectWriter::getRelocType(MCContext &Ctx,
     return COFF::IMAGE_REL_ARM_ABSOLUTE;
   }
   case FK_Data_4:
-    switch (Modifier) {
+    switch (Spec) {
     case MCSymbolRefExpr::VK_COFF_IMGREL32:
       return COFF::IMAGE_REL_ARM_ADDR32NB;
     case MCSymbolRefExpr::VK_SECREL:

llvm/lib/Target/PowerPC/MCTargetDesc/PPCXCOFFObjectWriter.cpp

@@ -41,7 +41,7 @@ llvm::createPPCXCOFFObjectWriter(bool Is64Bit) {
 std::pair<uint8_t, uint8_t> PPCXCOFFObjectWriter::getRelocTypeAndSignSize(
     const MCValue &Target, const MCFixup &Fixup, bool IsPCRel) const {
   const auto Specifier =
-      Target.isAbsolute() ? PPCMCExpr::VK_None : getSpecifier(Target.getSymA());
+      Target.isAbsolute() ? PPCMCExpr::VK_None : Target.getSymSpecifier();
   // People from AIX OS team says AIX link editor does not care about
   // the sign bit in the relocation entry "most" of the time.
   // The system assembler seems to set the sign bit on relocation entry

llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp

@@ -51,7 +51,7 @@ unsigned RISCVELFObjectWriter::getRelocType(MCContext &Ctx,
                                             const MCFixup &Fixup,
                                             bool IsPCRel) const {
   assert((!Target.getSymA() ||
-          Target.getSymA()->getKind() == MCSymbolRefExpr::VK_None) &&
+          Target.getSymSpecifier() == MCSymbolRefExpr::VK_None) &&
          "sym@specifier should have been rejected");
   const MCExpr *Expr = Fixup.getValue();
   // Determine the type of the relocation

llvm/lib/Target/SystemZ/MCTargetDesc/SystemZELFObjectWriter.cpp

@@ -220,7 +220,7 @@ unsigned SystemZELFObjectWriter::getRelocType(MCContext &Ctx,
 bool SystemZELFObjectWriter::needsRelocateWithSymbol(const MCValue &V,
                                                      const MCSymbol &Sym,
                                                      unsigned Type) const {
-  switch (getSpecifier(V.getSymA())) {
+  switch (V.getSymSpecifier()) {
   case SystemZMCExpr::VK_GOT:
   case SystemZMCExpr::VK_PLT:
     return true;

llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp

@@ -744,8 +744,7 @@ bool X86AsmBackend::fixupNeedsRelaxationAdvanced(const MCAssembler &Asm,
   if (Fixup.getKind() == FK_Data_1) {
     MCValue Target;
     if (Fixup.getValue()->evaluateAsRelocatable(Target, &Asm) &&
-        Target.getSymA() &&
-        getSpecifier(Target.getSymA()) == X86MCExpr::VK_ABS8)
+        Target.getSymA() && Target.getSymSpecifier() == X86MCExpr::VK_ABS8)
       return false;
   }
   return true;