Bug fixes & module name cleanup.

Unify actionHasOutput w/ doesActionProduceOutput & correct both.
Do not set an output filename if there is no output.
Add test to ensure no output is created in immediate mode.

Restore NFC module name computation.

Author: davidungar

include/swift/Frontend/FrontendOptions.h

@@ -514,9 +514,6 @@ class FrontendOptions {
   /// -dump-scope-maps.
   SmallVector<std::pair<unsigned, unsigned>, 2> DumpScopeMapLocations;
 
-  /// Indicates whether the RequestedAction has output.
-  bool actionHasOutput() const;
-
   /// Indicates whether the RequestedAction will immediately run code.
   bool actionIsImmediate() const;
 
@@ -551,6 +548,7 @@ class FrontendOptions {
 
   static bool doesActionProduceOutput(ActionType);
   static bool doesActionProduceTextualOutput(ActionType);
+  static bool doesActionImplyMainModule(ActionType);
 };
 
 }

lib/Frontend/CompilerInvocation.cpp

@@ -640,7 +640,8 @@ bool FrontendArgsToOptionsConverter::computeModuleName() {
       (Opts.ModuleName != STDLIB_NAME || Opts.ParseStdlib)) {
     return false;
   }
-  if (!Opts.actionHasOutput() || Opts.isCompilingExactlyOneSwiftFile()) {
+  if (FrontendOptions::doesActionImplyMainModule(Opts.RequestedAction) ||
+      Opts.isCompilingExactlyOneSwiftFile()) {
     Opts.ModuleName = "main";
     return false;
   }
@@ -680,10 +681,10 @@ bool FrontendArgsToOptionsConverter::computeFallbackModuleName() {
 }
 
 bool FrontendArgsToOptionsConverter::computeOutputFilenames() {
-  assert(
-      FrontendOptions::doesActionProduceOutput(Opts.RequestedAction) ||
-      !FrontendOptions::doesActionProduceTextualOutput(Opts.RequestedAction));
-
+  if (!FrontendOptions::doesActionProduceOutput(Opts.RequestedAction)) {
+    Opts.OutputFilenames.clear();
+    return false;
+  }
   ArrayRef<std::string> outputFilenamesFromCommandLineOrFilelist =
       getOutputFilenamesFromCommandLineOrFilelist();
 

lib/Frontend/FrontendOptions.cpp

@@ -96,8 +96,8 @@ void FrontendInputs::transformInputFilenames(
   }
 }
 
-bool FrontendOptions::actionHasOutput() const {
-  switch (RequestedAction) {
+bool FrontendOptions::doesActionImplyMainModule(ActionType action) {
+  switch (action) {
   case ActionType::NoneAction:
   case ActionType::Parse:
   case ActionType::Typecheck:
@@ -108,24 +108,24 @@ bool FrontendOptions::actionHasOutput() const {
   case ActionType::PrintAST:
   case ActionType::DumpScopeMaps:
   case ActionType::DumpTypeRefinementContexts:
-    return false;
+    return true;
   case ActionType::EmitPCH:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
   case ActionType::EmitSIBGen:
   case ActionType::EmitSIB:
   case ActionType::EmitModuleOnly:
   case ActionType::MergeModules:
-    return true;
+    return false;
   case ActionType::Immediate:
   case ActionType::REPL:
-    return false;
+    return true;
   case ActionType::EmitAssembly:
   case ActionType::EmitIR:
   case ActionType::EmitBC:
   case ActionType::EmitObject:
   case ActionType::EmitImportedModules:
-    return true;
+    return false;
   }
   llvm_unreachable("Unknown ActionType");
 }
@@ -406,37 +406,35 @@ bool FrontendOptions::canActionEmitModuleDoc(ActionType action) {
 
 bool FrontendOptions::doesActionProduceOutput(ActionType action) {
   switch (action) {
-    // FIXME: Some of these don't actually produce output
-    // but for now stay consistent with the status quo.
-  case ActionType::NoneAction:
-  case ActionType::EmitPCH:
-  case ActionType::EmitSIBGen:
-  case ActionType::EmitSIB:
-  case ActionType::MergeModules:
-  case ActionType::EmitModuleOnly:
-  case ActionType::EmitBC:
-  case ActionType::EmitObject:
   case ActionType::Parse:
   case ActionType::Typecheck:
   case ActionType::DumpParse:
-  case ActionType::DumpInterfaceHash:
   case ActionType::DumpAST:
   case ActionType::EmitSyntax:
+  case ActionType::DumpInterfaceHash:
   case ActionType::PrintAST:
   case ActionType::DumpScopeMaps:
   case ActionType::DumpTypeRefinementContexts:
-  case ActionType::EmitImportedModules:
+  case ActionType::EmitPCH:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
+  case ActionType::EmitSIBGen:
+  case ActionType::EmitSIB:
+  case ActionType::EmitModuleOnly:
   case ActionType::EmitAssembly:
   case ActionType::EmitIR:
+  case ActionType::EmitBC:
+  case ActionType::EmitObject:
+  case ActionType::EmitImportedModules:
+  case ActionType::MergeModules:
     return true;
 
+  case ActionType::NoneAction:
   case ActionType::Immediate:
   case ActionType::REPL:
-    // These modes have no frontend-generated output.
     return false;
   }
+  llvm_unreachable("Unknown ActionType");
 }
 
 bool FrontendOptions::doesActionProduceTextualOutput(ActionType action) {

test/Frontend/immediate-mode-no-output.swift

@@ -0,0 +1 @@
+// RUN: rm -rf %t &&  mkdir -p %t && cd %t && echo >test.swift && %swift  -interpret test.swift &&  rm test.swift && test `ls | wc -w` -eq 0