Xtensa: Migrate to newer relocation specifier representation

* Rename specifier constants from XtensaMCExpr::Specifier::VK_ to
  Xtensa::S_, following Sparc and VE.
* Use MCAsmInfo::printSpecifierExpr instead of MCExpr::print.
* Remove unneeded XtensaMCExpr. Just use MCSpecifierExpr when a
  specifier is needed.

Author: MaskRay

llvm/lib/Target/Xtensa/MCTargetDesc/CMakeLists.txt

@@ -4,7 +4,6 @@ add_llvm_component_library(LLVMXtensaDesc
   XtensaInstPrinter.cpp
   XtensaMCAsmInfo.cpp
   XtensaMCCodeEmitter.cpp
-  XtensaMCExpr.cpp
   XtensaMCTargetDesc.cpp
   XtensaTargetStreamer.cpp
 

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaInstPrinter.cpp

@@ -15,6 +15,7 @@
 #include "XtensaInstPrinter.h"
 #include "MCTargetDesc/XtensaMCExpr.h"
 #include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegister.h"
@@ -35,14 +36,7 @@ static void printExpr(const MCExpr *Expr, raw_ostream &OS) {
   if (!(SRE = cast<MCSymbolRefExpr>(Expr)))
     assert(false && "Unexpected MCExpr type.");
 
-  auto Spec = XtensaMCExpr::Specifier(SRE->getKind());
-  switch (Spec) {
-  case XtensaMCExpr::VK_None:
-    break;
-  // TODO
-  default:
-    report_fatal_error("Invalid kind!");
-  }
+  assert(SRE->getSpecifier() == 0);
 
   OS << SRE->getSymbol();
 
@@ -51,9 +45,6 @@ static void printExpr(const MCExpr *Expr, raw_ostream &OS) {
       OS << '+';
     OS << Offset;
   }
-
-  if (Spec != XtensaMCExpr::VK_None)
-    OS << ')';
 }
 
 void XtensaInstPrinter::printOperand(const MCOperand &MC, raw_ostream &O) {
@@ -97,7 +88,7 @@ void XtensaInstPrinter::printBranchTarget(const MCInst *MI, uint64_t Address,
     int64_t Val = MC.getImm() + 4;
     printPCRelImm(Address, Val, O);
   } else if (MC.isExpr())
-    MC.getExpr()->print(O, &MAI);
+    MAI.printExpr(O, *MC.getExpr());
   else
     llvm_unreachable("Invalid operand");
 }
@@ -109,7 +100,7 @@ void XtensaInstPrinter::printLoopTarget(const MCInst *MI, uint64_t Address,
     int64_t Val = MC.getImm() + 4;
     printPCRelImm(Address, Val, O);
   } else if (MC.isExpr())
-    MC.getExpr()->print(O, &MAI, true);
+    MAI.printExpr(O, *MC.getExpr());
   else
     llvm_unreachable("Invalid operand");
 }
@@ -121,7 +112,7 @@ void XtensaInstPrinter::printJumpTarget(const MCInst *MI, uint64_t Address,
     int64_t Val = MC.getImm() + 4;
     printPCRelImm(Address, Val, O);
   } else if (MC.isExpr())
-    MC.getExpr()->print(O, &MAI);
+    MAI.printExpr(O, *MC.getExpr());
   else
     llvm_unreachable("Invalid operand");
   ;
@@ -168,7 +159,7 @@ void XtensaInstPrinter::printL32RTarget(const MCInst *MI, uint64_t Address,
       printPCRelImm(Address, Value, O);
     }
   } else if (MC.isExpr())
-    MC.getExpr()->print(O, &MAI);
+    MAI.printExpr(O, *MC.getExpr());
   else
     llvm_unreachable("Invalid operand");
 }

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCAsmInfo.cpp

@@ -13,6 +13,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "XtensaMCAsmInfo.h"
+#include "XtensaMCExpr.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/Triple.h"
 
 using namespace llvm;
@@ -30,3 +32,22 @@ XtensaMCAsmInfo::XtensaMCAsmInfo(const Triple &TT) {
   ExceptionsType = ExceptionHandling::DwarfCFI;
   AlignmentIsInBytes = false;
 }
+
+void XtensaMCAsmInfo::printSpecifierExpr(raw_ostream &OS,
+                                         const MCSpecifierExpr &Expr) const {
+  StringRef S = Xtensa::getSpecifierName(Expr.getSpecifier());
+  if (!S.empty())
+    OS << '%' << S << '(';
+  printExpr(OS, *Expr.getSubExpr());
+  if (!S.empty())
+    OS << ')';
+}
+
+uint8_t Xtensa::parseSpecifier(StringRef name) { return 0; }
+
+StringRef Xtensa::getSpecifierName(uint8_t S) {
+  switch (S) {
+  default:
+    llvm_unreachable("Invalid ELF symbol kind");
+  }
+}

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCAsmInfo.h

@@ -23,6 +23,9 @@ class Triple;
 class XtensaMCAsmInfo : public MCAsmInfoELF {
 public:
   explicit XtensaMCAsmInfo(const Triple &TT);
+
+  void printSpecifierExpr(raw_ostream &OS,
+                          const MCSpecifierExpr &Expr) const override;
 };
 
 } // namespace llvm

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCExpr.cpp

@@ -20,24 +20,13 @@
 namespace llvm {
 
 class StringRef;
-class XtensaMCExpr : public MCSpecifierExpr {
-public:
-  using Specifier = uint16_t;
-  enum { VK_None, VK_TPOFF };
 
-private:
-  explicit XtensaMCExpr(const MCExpr *Expr, Specifier S)
-      : MCSpecifierExpr(Expr, S) {}
+namespace Xtensa {
+enum Specifier { S_None, S_TPOFF };
 
-public:
-  static const XtensaMCExpr *create(const MCExpr *Expr, Specifier,
-                                    MCContext &Ctx);
-
-  void printImpl(raw_ostream &OS, const MCAsmInfo *MAI) const override;
-
-  static Specifier parseSpecifier(StringRef name);
-  static StringRef getSpecifierName(Specifier Kind);
-};
+uint8_t parseSpecifier(StringRef name);
+StringRef getSpecifierName(uint8_t S);
+} // namespace Xtensa
 
 } // end namespace llvm.
 

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaMCExpr.h

@@ -32,13 +32,13 @@
 
 using namespace llvm;
 
-static XtensaMCExpr::Specifier
+static Xtensa::Specifier
 getModifierSpecifier(XtensaCP::XtensaCPModifier Modifier) {
   switch (Modifier) {
   case XtensaCP::no_modifier:
-    return XtensaMCExpr::VK_None;
+    return Xtensa::S_None;
   case XtensaCP::TPOFF:
-    return XtensaMCExpr::VK_TPOFF;
+    return Xtensa::S_TPOFF;
   }
   report_fatal_error("Invalid XtensaCPModifier!");
 }
@@ -92,7 +92,7 @@ void XtensaAsmPrinter::emitMachineConstantPoolValue(
   MCSymbol *LblSym = GetCPISymbol(ACPV->getLabelId());
   auto *TS =
       static_cast<XtensaTargetStreamer *>(OutStreamer->getTargetStreamer());
-  XtensaMCExpr::Specifier VK = getModifierSpecifier(ACPV->getModifier());
+  auto Spec = getModifierSpecifier(ACPV->getModifier());
 
   if (ACPV->getModifier() != XtensaCP::no_modifier) {
     std::string SymName(MCSym->getName());
@@ -101,7 +101,7 @@ void XtensaAsmPrinter::emitMachineConstantPoolValue(
     MCSym = OutContext.getOrCreateSymbol(SymName);
   }
 
-  const MCExpr *Expr = MCSymbolRefExpr::create(MCSym, VK, OutContext);
+  const MCExpr *Expr = MCSymbolRefExpr::create(MCSym, Spec, OutContext);
   TS->emitLiteral(LblSym, Expr, false);
 }
 
@@ -227,8 +227,6 @@ XtensaAsmPrinter::LowerSymbolOperand(const MachineOperand &MO,
                                      MachineOperand::MachineOperandType MOTy,
                                      unsigned Offset) const {
   const MCSymbol *Symbol;
-  XtensaMCExpr::Specifier Kind = XtensaMCExpr::VK_None;
-
   switch (MOTy) {
   case MachineOperand::MO_GlobalAddress:
     Symbol = getSymbol(MO.getGlobal());
@@ -257,7 +255,6 @@ XtensaAsmPrinter::LowerSymbolOperand(const MachineOperand &MO,
   }
 
   const MCExpr *ME = MCSymbolRefExpr::create(Symbol, OutContext);
-
   if (Offset) {
     // Assume offset is never negative.
     assert(Offset > 0);