[llvm-objdump] [NFC] Factor out DisassemblerTarget class.

This is a preparation for ARM64EC/ARM64X binaries, which may contain both ARM64
and x86_64 code in the same file. llvm-objdump already has partial support for
mixing disassemblers for ARM thumb mode support. However, for ARM64EC we can't
share MCContext, MCInstrAnalysis and PrettyPrinter instances. This patch
provides additional abstraction which makes adding mixed code support later in
the series easier.

Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D149093

Author: cjacek

llvm/tools/llvm-objdump/llvm-objdump.cpp

@@ -836,6 +836,92 @@ PrettyPrinter &selectPrettyPrinter(Triple const &Triple) {
     return AArch64PrettyPrinterInst;
   }
 }
+
+class DisassemblerTarget {
+public:
+  const Target *TheTarget;
+  std::unique_ptr<const MCSubtargetInfo> SubtargetInfo;
+  std::shared_ptr<MCContext> Context;
+  std::unique_ptr<MCDisassembler> DisAsm;
+  std::shared_ptr<const MCInstrAnalysis> InstrAnalysis;
+  std::shared_ptr<MCInstPrinter> InstPrinter;
+  PrettyPrinter *PrettyPrinter;
+
+  DisassemblerTarget(const Target *TheTarget, ObjectFile &Obj,
+                     StringRef TripleName, StringRef MCPU,
+                     SubtargetFeatures &Features);
+  DisassemblerTarget(DisassemblerTarget &Other, SubtargetFeatures &Features);
+
+private:
+  MCTargetOptions Options;
+  std::shared_ptr<const MCRegisterInfo> RegisterInfo;
+  std::shared_ptr<const MCAsmInfo> AsmInfo;
+  std::shared_ptr<const MCInstrInfo> InstrInfo;
+  std::shared_ptr<MCObjectFileInfo> ObjectFileInfo;
+};
+
+DisassemblerTarget::DisassemblerTarget(const Target *TheTarget, ObjectFile &Obj,
+                                       StringRef TripleName, StringRef MCPU,
+                                       SubtargetFeatures &Features)
+    : TheTarget(TheTarget),
+      PrettyPrinter(&selectPrettyPrinter(Triple(TripleName))),
+      RegisterInfo(TheTarget->createMCRegInfo(TripleName)) {
+  if (!RegisterInfo)
+    reportError(Obj.getFileName(), "no register info for target " + TripleName);
+
+  // Set up disassembler.
+  AsmInfo.reset(TheTarget->createMCAsmInfo(*RegisterInfo, TripleName, Options));
+  if (!AsmInfo)
+    reportError(Obj.getFileName(), "no assembly info for target " + TripleName);
+
+  SubtargetInfo.reset(
+      TheTarget->createMCSubtargetInfo(TripleName, MCPU, Features.getString()));
+  if (!SubtargetInfo)
+    reportError(Obj.getFileName(),
+                "no subtarget info for target " + TripleName);
+  InstrInfo.reset(TheTarget->createMCInstrInfo());
+  if (!InstrInfo)
+    reportError(Obj.getFileName(),
+                "no instruction info for target " + TripleName);
+  Context =
+      std::make_shared<MCContext>(Triple(TripleName), AsmInfo.get(),
+                                  RegisterInfo.get(), SubtargetInfo.get());
+
+  // FIXME: for now initialize MCObjectFileInfo with default values
+  ObjectFileInfo.reset(
+      TheTarget->createMCObjectFileInfo(*Context, /*PIC=*/false));
+  Context->setObjectFileInfo(ObjectFileInfo.get());
+
+  DisAsm.reset(TheTarget->createMCDisassembler(*SubtargetInfo, *Context));
+  if (!DisAsm)
+    reportError(Obj.getFileName(), "no disassembler for target " + TripleName);
+
+  InstrAnalysis.reset(TheTarget->createMCInstrAnalysis(InstrInfo.get()));
+
+  int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
+  InstPrinter.reset(TheTarget->createMCInstPrinter(Triple(TripleName),
+                                                   AsmPrinterVariant, *AsmInfo,
+                                                   *InstrInfo, *RegisterInfo));
+  if (!InstPrinter)
+    reportError(Obj.getFileName(),
+                "no instruction printer for target " + TripleName);
+  InstPrinter->setPrintImmHex(PrintImmHex);
+  InstPrinter->setPrintBranchImmAsAddress(true);
+  InstPrinter->setSymbolizeOperands(SymbolizeOperands);
+  InstPrinter->setMCInstrAnalysis(InstrAnalysis.get());
+}
+
+DisassemblerTarget::DisassemblerTarget(DisassemblerTarget &Other,
+                                       SubtargetFeatures &Features)
+    : TheTarget(Other.TheTarget),
+      SubtargetInfo(TheTarget->createMCSubtargetInfo(TripleName, MCPU,
+                                                     Features.getString())),
+      Context(Other.Context),
+      DisAsm(TheTarget->createMCDisassembler(*SubtargetInfo, *Context)),
+      InstrAnalysis(Other.InstrAnalysis), InstPrinter(Other.InstPrinter),
+      PrettyPrinter(Other.PrettyPrinter), RegisterInfo(Other.RegisterInfo),
+      AsmInfo(Other.AsmInfo), InstrInfo(Other.InstrInfo),
+      ObjectFileInfo(Other.ObjectFileInfo) {}
 } // namespace
 
 static uint8_t getElfSymbolType(const ObjectFile &Obj, const SymbolRef &Sym) {
@@ -1326,15 +1412,14 @@ fetchBinaryByBuildID(const ObjectFile &Obj) {
   return std::move(*DebugBinary);
 }
 
-static void disassembleObject(const Target *TheTarget, ObjectFile &Obj,
-                              const ObjectFile &DbgObj, MCContext &Ctx,
-                              MCDisassembler *PrimaryDisAsm,
-                              MCDisassembler *SecondaryDisAsm,
-                              const MCInstrAnalysis *MIA, MCInstPrinter *IP,
-                              const MCSubtargetInfo *PrimarySTI,
-                              const MCSubtargetInfo *SecondarySTI,
-                              PrettyPrinter &PIP, SourcePrinter &SP,
-                              bool InlineRelocs) {
+static void
+disassembleObject(const Target *TheTarget, ObjectFile &Obj,
+                  const ObjectFile &DbgObj, MCContext &Ctx,
+                  MCDisassembler *PrimaryDisAsm,
+                  std::optional<DisassemblerTarget> &SecondaryTarget,
+                  const MCInstrAnalysis *MIA, MCInstPrinter *IP,
+                  const MCSubtargetInfo *PrimarySTI, PrettyPrinter &PIP,
+                  SourcePrinter &SP, bool InlineRelocs) {
   const MCSubtargetInfo *STI = PrimarySTI;
   MCDisassembler *DisAsm = PrimaryDisAsm;
   bool PrimaryIsThumb = false;
@@ -1790,13 +1875,17 @@ static void disassembleObject(const Target *TheTarget, ObjectFile &Obj,
         if (!MappingSymbols.empty()) {
           char Kind = getMappingSymbolKind(MappingSymbols, Index);
           DumpARMELFData = Kind == 'd';
-          if (SecondarySTI) {
+          if (SecondaryTarget) {
             if (Kind == 'a') {
-              STI = PrimaryIsThumb ? SecondarySTI : PrimarySTI;
-              DisAsm = PrimaryIsThumb ? SecondaryDisAsm : PrimaryDisAsm;
+              STI = PrimaryIsThumb ? SecondaryTarget->SubtargetInfo.get()
+                                   : PrimarySTI;
+              DisAsm = PrimaryIsThumb ? SecondaryTarget->DisAsm.get()
+                                      : PrimaryDisAsm;
             } else if (Kind == 't') {
-              STI = PrimaryIsThumb ? PrimarySTI : SecondarySTI;
-              DisAsm = PrimaryIsThumb ? PrimaryDisAsm : SecondaryDisAsm;
+              STI = PrimaryIsThumb ? PrimarySTI
+                                   : SecondaryTarget->SubtargetInfo.get();
+              DisAsm = PrimaryIsThumb ? PrimaryDisAsm
+                                      : SecondaryTarget->DisAsm.get();
             }
           }
         }
@@ -2064,20 +2153,6 @@ static void disassembleObject(ObjectFile *Obj, bool InlineRelocs) {
     Features.AddFeature("+all");
   }
 
-  std::unique_ptr<const MCRegisterInfo> MRI(
-      TheTarget->createMCRegInfo(TripleName));
-  if (!MRI)
-    reportError(Obj->getFileName(),
-                "no register info for target " + TripleName);
-
-  // Set up disassembler.
-  MCTargetOptions MCOptions;
-  std::unique_ptr<const MCAsmInfo> AsmInfo(
-      TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
-  if (!AsmInfo)
-    reportError(Obj->getFileName(),
-                "no assembly info for target " + TripleName);
-
   if (MCPU.empty())
     MCPU = Obj->tryGetCPUName().value_or("").str();
 
@@ -2104,57 +2179,23 @@ static void disassembleObject(ObjectFile *Obj, bool InlineRelocs) {
     }
   }
 
-  std::unique_ptr<const MCSubtargetInfo> STI(
-      TheTarget->createMCSubtargetInfo(TripleName, MCPU, Features.getString()));
-  if (!STI)
-    reportError(Obj->getFileName(),
-                "no subtarget info for target " + TripleName);
-  std::unique_ptr<const MCInstrInfo> MII(TheTarget->createMCInstrInfo());
-  if (!MII)
-    reportError(Obj->getFileName(),
-                "no instruction info for target " + TripleName);
-  MCContext Ctx(Triple(TripleName), AsmInfo.get(), MRI.get(), STI.get());
-  // FIXME: for now initialize MCObjectFileInfo with default values
-  std::unique_ptr<MCObjectFileInfo> MOFI(
-      TheTarget->createMCObjectFileInfo(Ctx, /*PIC=*/false));
-  Ctx.setObjectFileInfo(MOFI.get());
-
-  std::unique_ptr<MCDisassembler> DisAsm(
-      TheTarget->createMCDisassembler(*STI, Ctx));
-  if (!DisAsm)
-    reportError(Obj->getFileName(), "no disassembler for target " + TripleName);
+  DisassemblerTarget PrimaryTarget(TheTarget, *Obj, TripleName, MCPU, Features);
 
   // If we have an ARM object file, we need a second disassembler, because
   // ARM CPUs have two different instruction sets: ARM mode, and Thumb mode.
   // We use mapping symbols to switch between the two assemblers, where
   // appropriate.
-  std::unique_ptr<MCDisassembler> SecondaryDisAsm;
-  std::unique_ptr<const MCSubtargetInfo> SecondarySTI;
-  if (isArmElf(*Obj) && !STI->checkFeatures("+mclass")) {
-    if (STI->checkFeatures("+thumb-mode"))
-      Features.AddFeature("-thumb-mode");
-    else
-      Features.AddFeature("+thumb-mode");
-    SecondarySTI.reset(TheTarget->createMCSubtargetInfo(TripleName, MCPU,
-                                                        Features.getString()));
-    SecondaryDisAsm.reset(TheTarget->createMCDisassembler(*SecondarySTI, Ctx));
-  }
-
-  std::unique_ptr<const MCInstrAnalysis> MIA(
-      TheTarget->createMCInstrAnalysis(MII.get()));
-
-  int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
-  std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
-      Triple(TripleName), AsmPrinterVariant, *AsmInfo, *MII, *MRI));
-  if (!IP)
-    reportError(Obj->getFileName(),
-                "no instruction printer for target " + TripleName);
-  IP->setPrintImmHex(PrintImmHex);
-  IP->setPrintBranchImmAsAddress(true);
-  IP->setSymbolizeOperands(SymbolizeOperands);
-  IP->setMCInstrAnalysis(MIA.get());
+  std::optional<DisassemblerTarget> SecondaryTarget;
 
-  PrettyPrinter &PIP = selectPrettyPrinter(Triple(TripleName));
+  if (isArmElf(*Obj)) {
+    if (!PrimaryTarget.SubtargetInfo->checkFeatures("+mclass")) {
+      if (PrimaryTarget.SubtargetInfo->checkFeatures("+thumb-mode"))
+        Features.AddFeature("-thumb-mode");
+      else
+        Features.AddFeature("+thumb-mode");
+      SecondaryTarget.emplace(PrimaryTarget, Features);
+    }
+  }
 
   const ObjectFile *DbgObj = Obj;
   if (!FetchedBinary.getBinary() && !Obj->hasDebugInfo()) {
@@ -2184,13 +2225,16 @@ static void disassembleObject(ObjectFile *Obj, bool InlineRelocs) {
   SourcePrinter SP(DbgObj, TheTarget->getName());
 
   for (StringRef Opt : DisassemblerOptions)
-    if (!IP->applyTargetSpecificCLOption(Opt))
+    if (!PrimaryTarget.InstPrinter->applyTargetSpecificCLOption(Opt))
       reportError(Obj->getFileName(),
                   "Unrecognized disassembler option: " + Opt);
 
-  disassembleObject(TheTarget, *Obj, *DbgObj, Ctx, DisAsm.get(),
-                    SecondaryDisAsm.get(), MIA.get(), IP.get(), STI.get(),
-                    SecondarySTI.get(), PIP, SP, InlineRelocs);
+  disassembleObject(TheTarget, *Obj, *DbgObj, *PrimaryTarget.Context.get(),
+                    PrimaryTarget.DisAsm.get(), SecondaryTarget,
+                    PrimaryTarget.InstrAnalysis.get(),
+                    PrimaryTarget.InstPrinter.get(),
+                    PrimaryTarget.SubtargetInfo.get(),
+                    *PrimaryTarget.PrettyPrinter, SP, InlineRelocs);
 }
 
 void Dumper::printRelocations() {