[NFC] Upgrade CompileJobAction::InputInfo::Status to an enum class

Author: CodaFi

include/swift/Driver/Action.h

@@ -130,15 +130,28 @@ class JobAction : public Action {
 class IncrementalJobAction : public JobAction {
 public:
   struct InputInfo {
-    enum Status {
+    /// The status of an input known to the driver. These are used to affect
+    /// the scheduling decisions made during an incremental build.
+    ///
+    /// \Note The order of cases matters. They are ordered from least to
+    /// greatest impact on the incremental build schedule.
+    enum class Status {
+      /// The input to this job is up to date.
       UpToDate,
+      /// The input to this job has changed in a way that requires this job to
+      /// be rerun, but not in such a way that it requires a cascading rebuild.
       NeedsNonCascadingBuild,
+      /// The input to this job has changed in a way that requires this job to
+      /// be rerun, and in such a way that all jobs dependent upon this one
+      /// must be scheduled as well.
       NeedsCascadingBuild,
+      /// The input to this job was not known to the driver when it was last
+      /// run.
       NewlyAdded
     };
 
   public:
-    Status status = UpToDate;
+    Status status = Status::UpToDate;
     llvm::sys::TimePoint<> previousModTime;
 
     InputInfo() = default;

lib/Driver/Compilation.cpp

@@ -1608,8 +1608,8 @@ namespace driver {
           CompileJobAction::InputInfo info;
           info.previousModTime = entry.first->getInputModTime();
           info.status = entry.second ?
-            CompileJobAction::InputInfo::NeedsCascadingBuild :
-            CompileJobAction::InputInfo::NeedsNonCascadingBuild;
+            CompileJobAction::InputInfo::Status::NeedsCascadingBuild :
+            CompileJobAction::InputInfo::Status::NeedsNonCascadingBuild;
           inputs[&inputFile->getInputArg()] = info;
         }
       }
@@ -1626,7 +1626,7 @@ namespace driver {
 
           CompileJobAction::InputInfo info;
           info.previousModTime = entry->getInputModTime();
-          info.status = CompileJobAction::InputInfo::UpToDate;
+          info.status = CompileJobAction::InputInfo::Status::UpToDate;
           inputs[&inputFile->getInputArg()] = info;
         }
       }

lib/Driver/Driver.cpp

@@ -2755,6 +2755,7 @@ static void
 handleCompileJobCondition(Job *J, CompileJobAction::InputInfo inputInfo,
                           StringRef input, bool alwaysRebuildDependents) {
   if (inputInfo.status == CompileJobAction::InputInfo::NewlyAdded) {
+  using InputStatus = CompileJobAction::InputInfo::Status;
     J->setCondition(Job::Condition::NewlyAdded);
     return;
   }
@@ -2769,24 +2770,24 @@ handleCompileJobCondition(Job *J, CompileJobAction::InputInfo inputInfo,
   Job::Condition condition;
   if (hasValidModTime && J->getInputModTime() == inputInfo.previousModTime) {
     switch (inputInfo.status) {
-    case CompileJobAction::InputInfo::UpToDate:
-      if (llvm::sys::fs::exists(J->getOutput().getPrimaryOutputFilename()))
+    case InputStatus::UpToDate:
+      if (llvm::sys::fs::exists(output))
         condition = Job::Condition::CheckDependencies;
       else
         condition = Job::Condition::RunWithoutCascading;
       break;
-    case CompileJobAction::InputInfo::NeedsCascadingBuild:
+    case InputStatus::NeedsCascadingBuild:
       condition = Job::Condition::Always;
       break;
-    case CompileJobAction::InputInfo::NeedsNonCascadingBuild:
+    case InputStatus::NeedsNonCascadingBuild:
       condition = Job::Condition::RunWithoutCascading;
       break;
-    case CompileJobAction::InputInfo::NewlyAdded:
+    case InputStatus::NewlyAdded:
       llvm_unreachable("handled above");
     }
   } else {
     if (alwaysRebuildDependents ||
-        inputInfo.status == CompileJobAction::InputInfo::NeedsCascadingBuild) {
+        inputInfo.status == InputStatus::NeedsCascadingBuild) {
       condition = Job::Condition::Always;
     } else {
       condition = Job::Condition::RunWithoutCascading;