[Driver] Move some string definitions around (NFC)

include/swift/Driver/Action.h

@@ -17,6 +17,8 @@
 #include "swift/Driver/Types.h"
 #include "swift/Driver/Util.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/TimeValue.h"
 
 namespace llvm {

lib/Driver/Compilation.cpp

@@ -36,6 +36,8 @@
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/YAMLParser.h"
 
+#include "CompilationRecord.h"
+
 using namespace swift;
 using namespace swift::sys;
 using namespace swift::driver;
@@ -190,27 +192,24 @@ static void writeCompilationRecord(StringRef path, StringRef argsHash,
     out << "[" << time.seconds() << ", " << time.nanoseconds() << "]";
   };
 
-  out << "version: \"" << llvm::yaml::escape(version::getSwiftFullVersion())
+  using compilation_record::TopLevelKey;
+  out << compilation_record::getName(TopLevelKey::Version) << ": \""
+      << llvm::yaml::escape(version::getSwiftFullVersion())
       << "\"\n";
-  out << "options: \"" << llvm::yaml::escape(argsHash) << "\"\n";
-  out << "build_time: ";
+  out << compilation_record::getName(TopLevelKey::Options) << ": \""
+      << llvm::yaml::escape(argsHash) << "\"\n";
+  out << compilation_record::getName(TopLevelKey::BuildTime) << ": ";
   writeTimeValue(out, buildTime);
   out << "\n";
-  out << "inputs:\n";
+  out << compilation_record::getName(TopLevelKey::Inputs) << ":\n";
 
   for (auto &entry : inputs) {
     out << "  \"" << llvm::yaml::escape(entry.first->getValue()) << "\": ";
 
-    switch (entry.second.status) {
-    case CompileJobAction::InputInfo::UpToDate:
-      break;
-    case CompileJobAction::InputInfo::NewlyAdded:
-    case CompileJobAction::InputInfo::NeedsCascadingBuild:
-      out << "!dirty ";
-      break;
-    case CompileJobAction::InputInfo::NeedsNonCascadingBuild:
-      out << "!private ";
-      break;
+    using compilation_record::getIdentifierForInputInfoStatus;
+    auto Name = getIdentifierForInputInfoStatus(entry.second.status);
+    if (!Name.empty()) {
+      out << Name << " ";
     }
 
     writeTimeValue(out, entry.second.previousModTime);

lib/Driver/CompilationRecord.h

@@ -0,0 +1,85 @@
+//===--- CompilationRecord.h ------------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_DRIVER_COMPILATIONRECORD_H
+#define SWIFT_DRIVER_COMPILATIONRECORD_H
+
+#include "swift/Driver/Action.h"
+
+namespace swift {
+namespace driver {
+namespace compilation_record {
+
+/// Compilation record files (.swiftdeps files) are YAML files composed of these
+/// top-level keys.
+enum class TopLevelKey {
+  /// The key for the Swift compiler version used to produce the compilation
+  /// record.
+  Version,
+  /// The key for the list of arguments passed to the Swift compiler when
+  /// producing the compilation record.
+  Options,
+  /// The key for the time at which the build that produced the compilation
+  /// record started.
+  BuildTime,
+  /// The key for the list of inputs to the compilation that produced the
+  /// compilation record.
+  Inputs,
+};
+
+/// \returns A string representation of the given key.
+inline static StringRef getName(TopLevelKey Key) {
+  switch (Key) {
+  case TopLevelKey::Version: return "version";
+  case TopLevelKey::Options: return "options";
+  case TopLevelKey::BuildTime: return "build_time";
+  case TopLevelKey::Inputs: return "inputs";
+  }
+}
+
+/// \returns The string identifier used to represent the given status in a
+/// compilation record file (.swiftdeps file).
+///
+/// \note Not every InputInfo::Status has a unique identifier. For example,
+/// both NewlyAdded and NeedsCascadingBuild are represented as "!dirty".
+/// Therefore, this will not cleanly round-trip between InputInfo::Status and
+/// string identifiers.
+inline static StringRef
+getIdentifierForInputInfoStatus(CompileJobAction::InputInfo::Status Status) {
+  switch (Status) {
+  case CompileJobAction::InputInfo::UpToDate:
+    return "";
+  case CompileJobAction::InputInfo::NewlyAdded:
+  case CompileJobAction::InputInfo::NeedsCascadingBuild:
+    return "!dirty";
+  case CompileJobAction::InputInfo::NeedsNonCascadingBuild:
+    return "!private";
+  }
+}
+
+/// \returns The status corresponding to the string identifier used in a
+/// compilation record file (.swiftdeps file).
+inline static Optional<CompileJobAction::InputInfo::Status>
+getInfoStatusForIdentifier(StringRef Identifier) {
+  return llvm::StringSwitch<Optional<
+      CompileJobAction::InputInfo::Status>>(Identifier)
+    .Case("", CompileJobAction::InputInfo::UpToDate)
+    .Case("!dirty", CompileJobAction::InputInfo::NeedsCascadingBuild)
+    .Case("!private", CompileJobAction::InputInfo::NeedsNonCascadingBuild)
+    .Default(None);
+}
+
+} // end namespace compilation_record
+} // end namespace driver
+} // end namespace swift
+
+#endif

lib/Driver/Driver.cpp

@@ -52,6 +52,8 @@
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/raw_ostream.h"
 
+#include "CompilationRecord.h"
+
 #include <memory>
 
 using namespace swift;
@@ -262,20 +264,21 @@ static bool populateOutOfDateMap(InputInfoMap &map, StringRef argsHashStr,
     auto *key = cast<yaml::ScalarNode>(i->getKey());
     StringRef keyStr = key->getValue(scratch);
 
-    if (keyStr == "version") {
+    using compilation_record::TopLevelKey;
+    if (keyStr == compilation_record::getName(TopLevelKey::Version)) {
       auto *value = dyn_cast<yaml::ScalarNode>(i->getValue());
       if (!value)
         return true;
       versionValid =
           (value->getValue(scratch) == version::getSwiftFullVersion());
 
-    } else if (keyStr == "options") {
+    } else if (keyStr == compilation_record::getName(TopLevelKey::Options)) {
       auto *value = dyn_cast<yaml::ScalarNode>(i->getValue());
       if (!value)
         return true;
       optionsMatch = (argsHashStr == value->getValue(scratch));
 
-    } else if (keyStr == "build_time") {
+    } else if (keyStr == compilation_record::getName(TopLevelKey::BuildTime)) {
       auto *value = dyn_cast<yaml::SequenceNode>(i->getValue());
       if (!value)
         return true;
@@ -284,7 +287,7 @@ static bool populateOutOfDateMap(InputInfoMap &map, StringRef argsHashStr,
         return true;
       map[nullptr] = { InputInfo::NeedsCascadingBuild, timeVal };
 
-    } else if (keyStr == "inputs") {
+    } else if (keyStr == compilation_record::getName(TopLevelKey::Inputs)) {
       auto *inputMap = dyn_cast<yaml::MappingNode>(i->getValue());
       if (!inputMap)
         return true;
@@ -300,13 +303,9 @@ static bool populateOutOfDateMap(InputInfoMap &map, StringRef argsHashStr,
         if (!value)
           return true;
 
+        using compilation_record::getInfoStatusForIdentifier;
         auto previousBuildState =
-            llvm::StringSwitch<Optional<InputInfo::Status>>(value->getRawTag())
-              .Case("", InputInfo::UpToDate)
-              .Case("!dirty", InputInfo::NeedsCascadingBuild)
-              .Case("!private", InputInfo::NeedsNonCascadingBuild)
-              .Default(None);
-
+          getInfoStatusForIdentifier(value->getRawTag());
         if (!previousBuildState)
           return true;