Fix warnings in SIL

Author: Sasha Krassovsky

include/swift/SIL/AbstractionPattern.h

@@ -402,6 +402,7 @@ class AbstractionPattern {
     case Kind::Tuple:
       return false;
     }
+    llvm_unreachable("Unhandled AbstractionPatternKind in switch");
   }
 
   CanGenericSignature getGenericSignature() const {

lib/SIL/SILPrinter.cpp

@@ -2993,6 +2993,12 @@ void SILCoverageMap::dump() const {
 }
 
 #ifndef NDEBUG
+// Disable the "for use only in debugger" warning.
+#if SWIFT_COMPILER_IS_MSVC
+#pragma warning(push)
+#pragma warning(disable : 4996)
+#endif
+
 void SILDebugScope::dump(SourceManager &SM, llvm::raw_ostream &OS,
                          unsigned Indent) const {
   OS << "{\n";
@@ -3026,6 +3032,10 @@ void SILDebugScope::dump(SILModule &Mod) const {
   dump(Mod.getASTContext().SourceMgr);
 }
 
+#if SWIFT_COMPILER_IS_MSVC
+#pragma warning(pop)
+#endif
+
 #endif
 
 void SILSpecializeAttr::print(llvm::raw_ostream &OS) const {