Remove ~moduleonly Duplicate of Compilation Record

We thought we would need this while exploring  certain pre-build optimizations a la rdar://problem/37725110. This information was never used.

Author: CodaFi

include/swift/Driver/Compilation.h

@@ -206,15 +206,6 @@ class Compilation {
   /// of date.
   bool EnableIncrementalBuild;
 
-  /// When true, emit duplicated compilation record file whose filename is
-  /// suffixed with '~moduleonly'.
-  ///
-  /// This compilation record is used by '-emit-module'-only incremental builds
-  /// so that module-only builds do not affect compilation record file for
-  /// normal builds, while module-only incremental builds are able to use
-  /// artifacts of normal builds if they are already up to date.
-  bool OutputCompilationRecordForModuleOnlyBuild = false;
-
   /// Indicates whether groups of parallel frontend jobs should be merged
   /// together and run in composite "batch jobs" when possible, to reduce
   /// redundant work.
@@ -313,7 +304,6 @@ class Compilation {
               std::unique_ptr<llvm::opt::DerivedArgList> TranslatedArgs,
               InputFileList InputsWithTypes,
               std::string CompilationRecordPath,
-              bool OutputCompilationRecordForModuleOnlyBuild,
               StringRef ArgsHash, llvm::sys::TimePoint<> StartTime,
               llvm::sys::TimePoint<> LastBuildTime,
               size_t FilelistThreshold,

lib/Driver/Compilation.cpp

@@ -108,7 +108,6 @@ Compilation::Compilation(DiagnosticEngine &Diags,
                          std::unique_ptr<DerivedArgList> TranslatedArgs,
                          InputFileList InputsWithTypes,
                          std::string CompilationRecordPath,
-                         bool OutputCompilationRecordForModuleOnlyBuild,
                          StringRef ArgsHash,
                          llvm::sys::TimePoint<> StartTime,
                          llvm::sys::TimePoint<> LastBuildTime,
@@ -140,8 +139,6 @@ Compilation::Compilation(DiagnosticEngine &Diags,
     BuildStartTime(StartTime),
     LastBuildTime(LastBuildTime),
     EnableIncrementalBuild(EnableIncrementalBuild),
-    OutputCompilationRecordForModuleOnlyBuild(
-        OutputCompilationRecordForModuleOnlyBuild),
     EnableBatchMode(EnableBatchMode),
     BatchSeed(BatchSeed),
     BatchCount(BatchCount),
@@ -1815,12 +1812,6 @@ int Compilation::performJobsImpl(bool &abnormalExit,
     checkForOutOfDateInputs(Diags, InputInfo);
     writeCompilationRecord(CompilationRecordPath, ArgsHash, BuildStartTime,
                            InputInfo);
-
-    if (OutputCompilationRecordForModuleOnlyBuild) {
-      // TODO: Optimize with clonefile(2) ?
-      llvm::sys::fs::copy_file(CompilationRecordPath,
-                               CompilationRecordPath + "~moduleonly");
-    }
   }
   abnormalExit = State.hadAnyAbnormalExit();
   return State.getResult();

lib/Driver/Driver.cpp

@@ -404,10 +404,7 @@ class Driver::InputInfoMap
 using InputInfoMap = Driver::InputInfoMap;
 
 /// Get the filename for build record. Returns true if failed.
-/// Additionally, set 'outputBuildRecordForModuleOnlyBuild' to true if this is
-/// full compilation with swiftmodule.
 static bool getCompilationRecordPath(std::string &buildRecordPath,
-                                     bool &outputBuildRecordForModuleOnlyBuild,
                                      const OutputInfo &OI,
                                      const Optional<OutputFileMap> &OFM,
                                      DiagnosticEngine *Diags) {
@@ -430,17 +427,6 @@ static bool getCompilationRecordPath(std::string &buildRecordPath,
     return true;
   }
 
-  // In 'emit-module' only mode, use build-record filename suffixed with
-  // '~moduleonly'. So that module-only mode doesn't mess up build-record
-  // file for full compilation.
-  if (OI.CompilerOutputType == file_types::TY_SwiftModuleFile) {
-    buildRecordPath = buildRecordPath.append("~moduleonly");
-  } else if (OI.ShouldTreatModuleAsTopLevelOutput) {
-    // If we emit module along with full compilation, emit build record
-    // file for '-emit-module' only mode as well.
-    outputBuildRecordForModuleOnlyBuild = true;
-  }
-
   return false;
 }
 
@@ -960,8 +946,7 @@ Driver::buildCompilation(const ToolChain &TC,
       computeIncremental(ArgList.get(), ShowIncrementalBuildDecisions);
 
   std::string buildRecordPath;
-  bool outputBuildRecordForModuleOnlyBuild = false;
-  getCompilationRecordPath(buildRecordPath, outputBuildRecordForModuleOnlyBuild,
+  getCompilationRecordPath(buildRecordPath,
                            OI, OFM, Incremental ? &Diags : nullptr);
 
   SmallString<32> ArgsHash;
@@ -1050,7 +1035,6 @@ Driver::buildCompilation(const ToolChain &TC,
         std::move(TranslatedArgList),
         std::move(Inputs),
         buildRecordPath,
-        outputBuildRecordForModuleOnlyBuild,
         ArgsHash,
         StartTime,
         LastBuildTime,