[AST] Separate SourceFile from FileUnit.h

Like the last commit, SourceFile is used a lot by Parse and Sema, but
less so by the ClangImporter and (de)Serialization. Split it out to
cut down on recompilation times when something changes.

This commit does /not/ split the implementation of SourceFile out of
Module.cpp, which is where most of it lives. That might also be a
reasonable change, but the reason I was reluctant to is because a
number of SourceFile members correspond to the entry points in
ModuleDecl. Someone else can pick this up later if they decide it's a
good idea.

No functionality change.

Author: jrose-apple

include/swift/AST/FileUnit.h

@@ -20,12 +20,12 @@
 
 #include "swift/AST/DiagnosticConsumer.h"
 #include "swift/AST/DiagnosticEngine.h"
-#include "swift/AST/FileUnit.h"
 #include "swift/AST/IRGenOptions.h"
 #include "swift/AST/LinkLibrary.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/SILOptions.h"
 #include "swift/AST/SearchPathOptions.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/Basic/DiagnosticOptions.h"
 #include "swift/Basic/LangOptions.h"
 #include "swift/Basic/SourceManager.h"

include/swift/AST/SourceFile.h

@@ -18,8 +18,8 @@
 
 #include "swift/AST/ASTTypeIDs.h"
 #include "swift/AST/Evaluator.h"
-#include "swift/AST/FileUnit.h"
 #include "swift/AST/SimpleRequest.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/IDE/Utils.h"
 #include "swift/IDE/IDETypeIDs.h"
 

include/swift/Frontend/Frontend.h

@@ -19,6 +19,7 @@
 #define SWIFT_MIGRATOR_ASTMIGRATORPASS_H
 
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/Migrator/EditorAdapter.h"
 
 namespace swift {

include/swift/IDE/IDERequests.h

@@ -37,6 +37,7 @@
 #include "swift/AST/PropertyWrappers.h"
 #include "swift/AST/ProtocolConformance.h"
 #include "swift/AST/RawComment.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/SILLayout.h"
 #include "swift/AST/TypeCheckRequests.h"

include/swift/Migrator/ASTMigratorPass.h

@@ -17,12 +17,12 @@
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/AST/ASTVisitor.h"
-#include "swift/AST/FileUnit.h"
 #include "swift/AST/ForeignErrorConvention.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/ProtocolConformance.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/AST/TypeVisitor.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/QuotedString.h"

lib/AST/ASTContext.cpp

@@ -19,13 +19,13 @@
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Expr.h"
-#include "swift/AST/FileUnit.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/LazyResolver.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/Pattern.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/AST/Stmt.h"
 #include "swift/AST/TypeRepr.h"
 #include "swift/Basic/NullablePtr.h"

lib/AST/ASTDumper.cpp

@@ -20,12 +20,12 @@
 #include "swift/AST/Attr.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Expr.h"
-#include "swift/AST/FileUnit.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/LazyResolver.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/Pattern.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/AST/Stmt.h"
 #include "swift/AST/TypeRepr.h"
 #include "swift/Basic/STLExtras.h"

lib/AST/ASTScope.cpp

@@ -19,13 +19,13 @@
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/Expr.h"
-#include "swift/AST/FileUnit.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/LazyResolver.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
 #include "swift/AST/ParameterList.h"
 #include "swift/AST/Pattern.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/AST/Stmt.h"
 #include "swift/AST/TypeRepr.h"
 #include "swift/Basic/STLExtras.h"