[move-only] Make SILType::getRawASTType() private and make SILPrinter a friend so we can invoke that method.

The only place outside of SILType that uses getRawASTType() is in SILPrinter. It
is really an inner detail of SILType that we don't want to expose. With that in
mind, in this commit we:

1. Made SILType::getRawASTType() private.

2. Forward declared SILPrinter in SILType.h. We don't define it so no one can
use it, but the declaration still lets us make it a friend class of SILType
(allowing SILPrinter to still access getRawASTType()).

Author: gottesmm

include/swift/SIL/SILType.h

@@ -86,6 +86,8 @@ enum class SILValueCategory : uint8_t {
   Address,
 };
 
+class SILPrinter;
+
 /// SILType - A Swift type that has been lowered to a SIL representation type.
 /// In addition to the Swift type system, SIL adds "address" types that can
 /// reference any Swift type (but cannot take the address of an address). *T
@@ -113,6 +115,8 @@ class SILType {
 
   friend class Lowering::TypeConverter;
   friend struct llvm::DenseMapInfo<SILType>;
+  friend class SILPrinter;
+
 public:
   SILType() = default;
 
@@ -186,6 +190,7 @@ class SILType {
   ///    move only-ness of the value (which we can query separately anyways).
   CanType getASTType() const { return withoutMoveOnly().getRawASTType(); }
 
+private:
   /// Returns the canonical AST type references by this SIL type without looking
   /// through move only. Should only be used by internal utilities of SILType.
   CanType getRawASTType() const { return CanType(value.getPointer()); }

lib/SIL/IR/SILPrinter.cpp

@@ -532,8 +532,6 @@ static void printSILFunctionNameAndType(llvm::raw_ostream &OS,
 }
 
 namespace {
-  
-class SILPrinter;
 
 // 1. Accumulate opcode-specific comments in this stream.
 // 2. Start emitting comments: lineComments.start()
@@ -598,6 +596,10 @@ class LineComments : public raw_ostream {
   }
 };
 
+} // namespace
+
+namespace swift {
+
 /// SILPrinter class - This holds the internal implementation details of
 /// printing SIL structures.
 class SILPrinter : public SILInstructionVisitor<SILPrinter> {
@@ -2740,7 +2742,8 @@ class SILPrinter : public SILInstructionVisitor<SILPrinter> {
     }
   }
 };
-} // end anonymous namespace
+
+} // namespace swift
 
 static void printBlockID(raw_ostream &OS, SILBasicBlock *bb) {
   SILPrintContext Ctx(OS);