Review fixes:

Rename isThereAPrimaryInputWithAFilenameAt to isInputPrimary.
Remove spurious delayed_function_body_parsing.
Simply return type of getOutputFilenamesFromCommandLineOrFilelist.

include/swift/Frontend/FrontendOptions.h

@@ -158,7 +158,7 @@ public:
                : Optional<StringRef>();
   }
 
-  bool isThereAPrimaryInputWithAFilenameAt(unsigned i) const {
+  bool isInputPrimary(unsigned i) const {
     assertMustNotBeMoreThanOnePrimaryInput();
     if (Optional<SelectedInput> primaryInput = getOptionalPrimaryInput())
       return primaryInput->isFilename() && primaryInput->Index == i;

include/swift/Option/FrontendOptions.td

@@ -21,10 +21,6 @@ def triple : Separate<["-"], "triple">, Alias<target>;
 def color_diagnostics : Flag<["-"], "color-diagnostics">,
   HelpText<"Print diagnostics in color">;
 
-def delayed_function_body_parsing :
-  Flag<["-"], "delayed-function-body-parsing">,
-  HelpText<"Delay function body parsing until the end of all files">;
-
 def primary_file : Separate<["-"], "primary-file">,
   HelpText<"Produce output for this file, not the whole module">;
 

lib/Frontend/CompilerInvocation.cpp

@@ -288,7 +288,7 @@ private:
   /// Returns the output filenames on the command line or in the output
   /// filelist. If there
   /// were neither -o's nor an output filelist, returns an empty vector.
-  const std::vector<std::string> &getOutputFilenamesFromCommandLineOrFilelist();
+  ArrayRef<std::string> getOutputFilenamesFromCommandLineOrFilelist();
 
   bool checkForUnusedOutputPaths() const;
 
@@ -671,7 +671,7 @@ bool FrontendArgsToOptionsConverter::computeFallbackModuleName() {
     // selected".
     return false;
   }
-  const std::vector<std::string> &outputFilenames =
+  ArrayRef<std::string> outputFilenames =
       getOutputFilenamesFromCommandLineOrFilelist();
 
   bool isOutputAUniqueOrdinaryFile =
@@ -689,7 +689,7 @@ bool FrontendArgsToOptionsConverter::computeOutputFilenames() {
       FrontendOptions::doesActionProduceOutput(Opts.RequestedAction) ||
       !FrontendOptions::doesActionProduceTextualOutput(Opts.RequestedAction));
 
-  const std::vector<std::string> &outputFilenamesFromCommandLineOrFilelist =
+  ArrayRef<std::string> outputFilenamesFromCommandLineOrFilelist =
       getOutputFilenamesFromCommandLineOrFilelist();
 
   if (outputFilenamesFromCommandLineOrFilelist.size() > 1) {
@@ -887,7 +887,7 @@ void FrontendArgsToOptionsConverter::computeLLVMArgs() {
   }
 }
 
-const std::vector<std::string> &
+ArrayRef<std::string>
 FrontendArgsToOptionsConverter::getOutputFilenamesFromCommandLineOrFilelist() {
   if (cachedOutputFilenamesFromCommandLineOrFilelist) {
     return *cachedOutputFilenamesFromCommandLineOrFilelist;

lib/Frontend/Frontend.cpp

@@ -741,8 +741,7 @@ bool CompilerInstance::setUpForFileAt(unsigned i) {
     if (SILMode || (MainMode && filename(File) == "main.swift"))
       MainBufferID = ExistingBufferID.getValue();
 
-    if (Invocation.getFrontendOptions()
-            .Inputs.isThereAPrimaryInputWithAFilenameAt(i))
+    if (Invocation.getFrontendOptions().Inputs.isInputPrimary(i))
       PrimaryBufferID = ExistingBufferID.getValue();
 
     return false; // replaced by a memory buffer.
@@ -784,8 +783,7 @@ bool CompilerInstance::setUpForFileAt(unsigned i) {
   if (SILMode || (MainMode && filename(File) == "main.swift"))
     MainBufferID = BufferID;
 
-  if (Invocation.getFrontendOptions()
-          .Inputs.isThereAPrimaryInputWithAFilenameAt(i))
+  if (Invocation.getFrontendOptions().Inputs.isInputPrimary(i))
     PrimaryBufferID = BufferID;
 
   return false;