[ASTPrinter] Print expressions

Add new `-print-ast-decl` frontend option for only printing declarations,
to match existing behavior.
Some tests want to print the AST, but don't care about expressions.

The existing `-print-ast` option now prints function bodies and expressions.
Not all expressions are printed yet, but most common ones are.

Author: louisdh

include/swift/AST/PrintOptions.h

@@ -128,6 +128,9 @@ struct PrintOptions {
   /// Whether to print function definitions.
   bool FunctionDefinitions = false;
 
+  /// Whether to print expressions.
+  bool PrintExprs = false;
+  
   /// Whether to print '{ get set }' on readwrite computed properties.
   bool PrintGetSetOnRWProperties = true;
 
@@ -644,6 +647,20 @@ struct PrintOptions {
   ///
   /// This is only intended for debug output.
   static PrintOptions printEverything() {
+    PrintOptions result = printVerbose();
+    result.ExcludeAttrList.clear();
+    result.ExcludeAttrList.push_back(DAK_FixedLayout);
+    result.PrintStorageRepresentationAttrs = true;
+    result.AbstractAccessors = false;
+    result.PrintAccess = true;
+    result.SkipEmptyExtensionDecls = false;
+    result.SkipMissingMemberPlaceholders = false;
+    result.FunctionDefinitions = true;
+    result.PrintExprs = true;
+    return result;
+  }
+
+  static PrintOptions printDeclarations() {
     PrintOptions result = printVerbose();
     result.ExcludeAttrList.clear();
     result.ExcludeAttrList.push_back(DAK_FixedLayout);

include/swift/Frontend/FrontendOptions.h

@@ -118,6 +118,7 @@ class FrontendOptions {
     EmitSyntax,        ///< Parse and dump Syntax tree as JSON
     DumpAST,           ///< Parse, type-check, and dump AST
     PrintAST,          ///< Parse, type-check, and pretty-print AST
+    PrintASTDecl,      ///< Parse, type-check, and pretty-print AST declarations
 
     /// Parse and dump scope map.
     DumpScopeMaps,

include/swift/Option/Options.td

@@ -1051,6 +1051,10 @@ def print_ast : Flag<["-"], "print-ast">,
   HelpText<"Parse and type-check input file(s) and pretty print AST(s)">,
   ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
+def print_ast_decl : Flag<["-"], "print-ast-decl">,
+  HelpText<"Parse and type-check input file(s) and pretty print declarations from AST(s)">,
+  ModeOpt,
+  Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
 def dump_pcm : Flag<["-"], "dump-pcm">,
   HelpText<"Dump debugging information about a precompiled Clang module">,
   ModeOpt,