Add a swift-ide-test option to not print import declarations.

The import declarations get in the way when looking the results of
-enable-omit-needless-words.

Author: DougGregor

include/swift/AST/PrintOptions.h

@@ -105,6 +105,9 @@ struct PrintOptions {
   /// Whether to print destructors.
   bool SkipDeinit = false;
 
+  /// Whether to skip printing 'import' declarations.
+  bool SkipImports = false;
+
   /// Whether to print a long attribute like '\@available' on a separate line
   /// from the declaration or other attributes.
   bool PrintLongAttrsOnSeparateLines = false;

lib/AST/ASTPrinter.cpp

@@ -678,6 +678,10 @@ bool swift::shouldPrint(const Decl *D, PrintOptions &Options) {
     return false;
   }
 
+  if (Options.SkipImports && isa<ImportDecl>(D)) {
+    return false;
+  }
+
   if (Options.SkipImplicit && D->isImplicit())
     return false;
 

tools/swift-ide-test/swift-ide-test.cpp

@@ -244,6 +244,11 @@ SkipDeinit("skip-deinit",
                    llvm::cl::desc("Whether to skip printing destructors"),
                    llvm::cl::init(true));
 
+static llvm::cl::opt<bool>
+SkipImports("skip-imports",
+            llvm::cl::desc("Whether to skip printing import declarations"),
+            llvm::cl::init(false));
+
 static llvm::cl::opt<bool>
 SkipParameterNames("skip-parameter-names",
                    llvm::cl::desc("Whether to skip parameter names"),
@@ -2545,6 +2550,7 @@ int main(int argc, char *argv[]) {
     PrintOpts.SkipPrivateStdlibDecls = options::SkipPrivateStdlibDecls;
     PrintOpts.SkipUnavailable = options::SkipUnavailable;
     PrintOpts.SkipDeinit = options::SkipDeinit;
+    PrintOpts.SkipImports = options::SkipImports;
     if (options::SkipParameterNames) {
       PrintOpts.ArgAndParamPrinting
         = PrintOptions::ArgAndParamPrintingMode::ArgumentOnly;

utils/omit-needless-words.py

@@ -116,7 +116,7 @@ def help():
 sdkroot = subprocess.check_output(['xcrun', '--show-sdk-path', '--sdk', sdk]).rstrip()
 print('SDK Root = %s' % (sdkroot))
 
-swift_ide_test_cmd = [swift_ide_test, '-print-module', '-source-filename', source_filename, '-sdk', sdkroot, '-target', target, '-module-print-skip-overlay', '-skip-unavailable', '-module-print-submodules', '-skip-parameter-names', '-module-to-print=%s' % (module)]
+swift_ide_test_cmd = [swift_ide_test, '-print-module', '-source-filename', source_filename, '-sdk', sdkroot, '-target', target, '-module-print-skip-overlay', '-skip-unavailable', '-module-print-submodules', '-skip-parameter-names', '-skip-imports', '-module-to-print=%s' % (module)]
 omit_needless_words_args = ['-enable-omit-needless-words', '-enable-infer-default-arguments']
 
 # Determine the output files.