Fix build failure on windows (NFC)

DamonFool · DamonFool · commit b225f2d5d737 · 2023-10-01T08:06:34.000+08:00
C:\buildbot\mlir-x64-windows-ninja\llvm-project\llvm\lib\Object\MachOUniversalWriter.cpp(352) : error C2220: the following warning is treated as an error
C:\buildbot\mlir-x64-windows-ninja\llvm-project\llvm\lib\Object\MachOUniversalWriter.cpp(352) : warning C4715: 'llvm::object::writeUniversalBinaryToStream': not all control paths return a value
diff --git a/llvm/lib/Object/MachOUniversalWriter.cpp b/llvm/lib/Object/MachOUniversalWriter.cpp
@@ -349,6 +349,8 @@ Error object::writeUniversalBinaryToStream(ArrayRef<Slice> Slices,
     return writeUniversalArchsToStream<MachO::fat_arch>(FatHeader, Slices, Out);
     break;
   }
+
+  llvm_unreachable("Invalid fat header type");
 }
 
 Error object::writeUniversalBinary(ArrayRef<Slice> Slices,

Original file line number	Diff line number	Diff line change
`@@ -349,6 +349,8 @@ Error object::writeUniversalBinaryToStream(ArrayRef<Slice> Slices,`
`349`	`349`	`return writeUniversalArchsToStream<MachO::fat_arch>(FatHeader, Slices, Out);`
`350`	`350`	`break;`
`351`	`351`	`}`
	`352`	`+`
	`353`	`+ llvm_unreachable("Invalid fat header type");`
`352`	`354`	`}`
`353`	`355`
`354`	`356`	`Error object::writeUniversalBinary(ArrayRef<Slice> Slices,`