Fix CAS failures on rebranch

rdar://133264719 (🌲6.0+1 CAS failures on rebranch)

Because of eb22392, the LinkerOptions have been moved from
MCAssembler to MachObjectWriter, but MachOCASWriter doesn't have access
to those linker options, this patch fixes the bug by moving the
LinkerOptions to MCObjectWriter instead.

Author: rastogishubham

llvm/include/llvm/MC/MCMachObjectWriter.h

@@ -174,9 +174,6 @@ class MachObjectWriter : public MCObjectWriter {
   std::optional<unsigned> PtrAuthABIVersion;
   bool PtrAuthKernelABIVersion;
 
-  // The list of linker options for LC_LINKER_OPTION.
-  std::vector<std::vector<std::string>> LinkerOptions;
-
   MachSymbolData *findSymbolData(const MCSymbol &Sym);
 
   void writeWithPadding(StringRef Str, uint64_t Size);
@@ -281,9 +278,6 @@ class MachObjectWriter : public MCObjectWriter {
   void setPtrAuthKernelABIVersion(bool V) override {
     PtrAuthKernelABIVersion = V;
   }
-  std::vector<std::vector<std::string>> &getLinkerOptions() {
-    return LinkerOptions;
-  }
 
   /// @}
 

llvm/include/llvm/MC/MCObjectWriter.h

@@ -33,6 +33,9 @@ class MCValue;
 /// should be emitted as part of writeObject().
 class MCObjectWriter {
 protected:
+  // The list of linker options for LC_LINKER_OPTION.
+  std::vector<std::vector<std::string>> LinkerOptions;
+
   /// List of declared file names
   SmallVector<std::pair<std::string, size_t>, 0> FileNames;
   // XCOFF specific: Optional compiler version.
@@ -61,6 +64,10 @@ class MCObjectWriter {
   /// \name High-Level API
   /// @{
 
+  std::vector<std::vector<std::string>> &getLinkerOptions() {
+    return LinkerOptions;
+  }
+
   /// Perform any late binding of symbols (for example, to assign symbol
   /// indices for use when generating relocations).
   ///

llvm/lib/MC/MCMachOStreamer.cpp

@@ -232,7 +232,7 @@ void MCMachOStreamer::emitAssemblerFlag(MCAssemblerFlag Flag) {
 }
 
 void MCMachOStreamer::emitLinkerOptions(ArrayRef<std::string> Options) {
-  getWriter().getLinkerOptions().push_back(Options);
+  getMCObjectWriter().getLinkerOptions().push_back(Options);
 }
 
 void MCMachOStreamer::emitDataRegion(MCDataRegionType Kind) {

llvm/lib/MC/MCObjectWriter.cpp

@@ -25,6 +25,7 @@ void MCObjectWriter::reset() {
   EmitAddrsigSection = false;
   SubsectionsViaSymbols = false;
   CGProfile.clear();
+  LinkerOptions.clear();
 }
 
 bool MCObjectWriter::isSymbolRefDifferenceFullyResolved(

llvm/lib/MC/MachObjectWriter.cpp

@@ -63,7 +63,6 @@ void MachObjectWriter::reset() {
   TargetVariantVersionInfo.SDKVersion = VersionTuple();
   PtrAuthABIVersion = std::nullopt;
   PtrAuthKernelABIVersion = false;
-  LinkerOptions.clear();
   MCObjectWriter::reset();
 }
 

llvm/test/MC/MachO/linker-options.ll

@@ -6,6 +6,8 @@
 
 ; RUN: llc -O0 -mtriple=x86_64-apple-darwin -filetype=obj -o - %s | llvm-readobj --macho-linker-options - > %t
 ; RUN: FileCheck --check-prefix=CHECK-OBJ < %t %s
+; RUN: mkdir -p %t.dir/cas
+; RUN: llc -O0 -mtriple=x86_64-apple-darwin -filetype=obj --cas %t.dir/cas -cas-backend -o - %s | llvm-readobj --macho-linker-options - > %t
 
 ; CHECK-OBJ: Linker Options {
 ; CHECK-OBJ:   Size: 16