MCAssembler: Remove getWriterPtr

Commit 8728e09 (2018) introduced
getWriterPtr, which might be nullptr for MCAsmStreamer. This lured call
sites to use getWriterPtr when it's guaranteed to be non-null for
MCObjectstreamer. Remove this misleading API.

Author: MaskRay

llvm/include/llvm/MC/MCAssembler.h

@@ -187,8 +187,6 @@ class MCAssembler {
 
   MCCodeEmitter *getEmitterPtr() const { return Emitter.get(); }
 
-  MCObjectWriter *getWriterPtr() const { return Writer.get(); }
-
   MCAsmBackend &getBackend() const { return *Backend; }
 
   MCCodeEmitter &getEmitter() const { return *Emitter; }

llvm/lib/MC/MCAssembler.cpp

@@ -101,8 +101,8 @@ void MCAssembler::reset() {
     getBackendPtr()->reset();
   if (getEmitterPtr())
     getEmitterPtr()->reset();
-  if (getWriterPtr())
-    getWriterPtr()->reset();
+  if (Writer)
+    Writer->reset();
 }
 
 bool MCAssembler::registerSection(MCSection &Section) {
@@ -195,9 +195,9 @@ bool MCAssembler::evaluateFixup(const MCFixup &Fixup, const MCFragment *DF,
       const MCSymbol &SA = A->getSymbol();
       if (A->getKind() != MCSymbolRefExpr::VK_None || SA.isUndefined()) {
         IsResolved = false;
-      } else if (auto *Writer = getWriterPtr()) {
+      } else {
         IsResolved = (FixupFlags & MCFixupKindInfo::FKF_Constant) ||
-                     Writer->isSymbolRefDifferenceFullyResolvedImpl(
+                     getWriter().isSymbolRefDifferenceFullyResolvedImpl(
                          *this, SA, *DF, false, true);
       }
     }

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

@@ -560,11 +560,7 @@ bool RISCVAsmBackend::evaluateTargetFixup(const MCAssembler &Asm,
   if (A->getKind() != MCSymbolRefExpr::VK_None || SA.isUndefined())
     return false;
 
-  auto *Writer = Asm.getWriterPtr();
-  if (!Writer)
-    return false;
-
-  bool IsResolved = Writer->isSymbolRefDifferenceFullyResolvedImpl(
+  bool IsResolved = Asm.getWriter().isSymbolRefDifferenceFullyResolvedImpl(
       Asm, SA, *AUIPCDF, false, true);
   if (!IsResolved)
     return false;