Fix static_cast, move AIX specific code into XCOFFObjectWriter

Author: amy-kwan

llvm/include/llvm/MC/MCAssembler.h

@@ -229,7 +229,6 @@ class MCAssembler {
   }
 
   void setCPU(std::string TargetCPU) { CPU = std::move(TargetCPU); }
-  StringRef getCPU() const { return CPU; }
 
   bool registerSection(MCSection &Section);
   bool registerSymbol(const MCSymbol &Symbol);

llvm/include/llvm/MC/MCObjectWriter.h

@@ -36,8 +36,6 @@ class MCObjectWriter {
   SmallVector<std::pair<std::string, size_t>, 0> FileNames;
   // XCOFF specific: Optional compiler version.
   std::string CompilerVersion;
-  // AIX specific: CPU type.
-  std::string CPUType;
   std::vector<const MCSymbol *> AddrsigSyms;
   bool EmitAddrsigSection = false;
   bool SubsectionsViaSymbols = false;
@@ -102,7 +100,6 @@ class MCObjectWriter {
   void setCompilerVersion(StringRef CompilerVers) {
     CompilerVersion = CompilerVers;
   }
-  void setCPU(StringRef TargetCPU) { CPUType = TargetCPU; }
 
   /// Tell the object writer to emit an address-significance table during
   /// writeObject(). If this function is not called, all symbols are treated as

llvm/include/llvm/MC/MCXCOFFObjectWriter.h

@@ -40,11 +40,16 @@ class MCXCOFFObjectTargetWriter : public MCObjectTargetWriter {
 };
 
 class XCOFFObjectWriter : public MCObjectWriter {
+  // AIX specific CPU type.
+  std::string CPUType;
+
 public:
   virtual void addExceptionEntry(const MCSymbol *Symbol, const MCSymbol *Trap,
                                  unsigned LanguageCode, unsigned ReasonCode,
                                  unsigned FunctionSize, bool hasDebug) = 0;
   virtual void addCInfoSymEntry(StringRef Name, StringRef Metadata) = 0;
+  StringRef getCPUType() const { return CPUType; }
+  void setCPU(StringRef TargetCPU) { CPUType = TargetCPU; }
 };
 
 std::unique_ptr<MCObjectWriter>

llvm/lib/MC/XCOFFObjectWriter.cpp

@@ -1181,7 +1181,7 @@ void XCOFFWriter::writeSymbolTable(MCAssembler &Asm) {
     else
       LangID = XCOFF::TB_CPLUSPLUS;
 
-    uint8_t CpuID = XCOFF::getCpuID(CPUType);
+    uint8_t CpuID = XCOFF::getCpuID(getCPUType());
 
     int NumberOfFileAuxEntries = 1;
     if (!Vers.empty())

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

@@ -37,6 +37,7 @@
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCSymbolELF.h"
 #include "llvm/MC/MCSymbolXCOFF.h"
+#include "llvm/MC/MCXCOFFObjectWriter.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -426,8 +427,8 @@ class PPCTargetXCOFFStreamer : public PPCTargetStreamer {
   }
 
   void emitMachine(StringRef CPU) override {
-    MCXCOFFStreamer &XCOFFStreamer = static_cast<MCXCOFFStreamer &>(Streamer);
-    XCOFFStreamer.getAssembler().getWriter().setCPU(CPU);
+    static_cast<XCOFFObjectWriter &>(Streamer.getAssemblerPtr()->getWriter())
+        .setCPU(CPU);
   }
 
   void emitAbiVersion(int AbiVersion) override {