Merge pull request swiftlang#21177 from davidungar/A-exp-dep-graph-12-10-18

First cut at graph-based fine-grained experimental dependencies.

Author: David Ungar

include/swift/AST/ExperimentalDependencies.h

@@ -295,6 +295,11 @@ namespace swift {
     /// and faster rebuilds.
     bool EnableExperimentalDependencies = false;
 
+    /// To mimic existing system, set to false.
+    /// To experiment with including file-private and private dependency info,
+    /// set to true.
+    bool ExperimentalDependenciesIncludeIntrafileOnes = false;
+
     /// Sets the target we are building for and updates platform conditions
     /// to match.
     ///

include/swift/Basic/LangOptions.h

@@ -210,6 +210,16 @@ class Compilation {
   /// faster rebuilds.
   const bool EnableExperimentalDependencies;
 
+  /// Helpful for debugging, but slows down the driver. So, only turn on when
+  /// needed.
+  const bool VerifyExperimentalDependencyGraphAfterEveryImport;
+  /// Helpful for debugging, but slows down the driver. So, only turn on when
+  /// needed.
+  const bool EmitExperimentalDependencyDotFileAfterEveryImport;
+
+  /// Experiment with inter-file dependencies
+  const bool ExperimentalDependenciesIncludeIntrafileOnes;
+
   template <typename T>
   static T *unwrap(const std::unique_ptr<T> &p) {
     return p.get();
@@ -220,6 +230,7 @@ class Compilation {
       ArrayRefView<std::unique_ptr<T>, T *, Compilation::unwrap<T>>;
 
 public:
+  // clang-format off
   Compilation(DiagnosticEngine &Diags, const ToolChain &TC,
               OutputInfo const &OI,
               OutputLevel Level,
@@ -239,7 +250,11 @@ class Compilation {
               bool SaveTemps = false,
               bool ShowDriverTimeCompilation = false,
               std::unique_ptr<UnifiedStatsReporter> Stats = nullptr,
-              bool EnableExperimentalDependencies = false);
+              bool EnableExperimentalDependencies = false,
+              bool VerifyExperimentalDependencyGraphAfterEveryImport = false,
+              bool EmitExperimentalDependencyDotFileAfterEveryImport = false,
+              bool ExperimentalDependenciesIncludeIntrafileOnes = false);
+  // clang-format on
   ~Compilation();
 
   ToolChain const &getToolChain() const {
@@ -298,6 +313,18 @@ class Compilation {
     return EnableExperimentalDependencies;
   }
 
+  bool getVerifyExperimentalDependencyGraphAfterEveryImport() const {
+    return VerifyExperimentalDependencyGraphAfterEveryImport;
+  }
+
+  bool getEmitExperimentalDependencyDotFileAfterEveryImport() const {
+    return EmitExperimentalDependencyDotFileAfterEveryImport;
+  }
+
+  bool getExperimentalDependenciesIncludeIntrafileOnes() const {
+    return ExperimentalDependenciesIncludeIntrafileOnes;
+  }
+
   bool getBatchModeEnabled() const {
     return EnableBatchMode;
   }
@@ -312,7 +339,7 @@ class Compilation {
   bool getShowIncrementalBuildDecisions() const {
     return ShowIncrementalBuildDecisions;
   }
-  void setShowsIncrementalBuildDecisions(bool value = true) {
+  void setShowIncrementalBuildDecisions(bool value = true) {
     ShowIncrementalBuildDecisions = value;
   }
 
@@ -335,6 +362,12 @@ class Compilation {
     return Stats.get();
   }
 
+  /// True if extra work has to be done when tracing through the dependency
+  /// graph, either in order to print dependencies or to collect statistics.
+  bool getTraceDependencies() const {
+    return getShowIncrementalBuildDecisions() || getStatsReporter();
+  }
+
   OutputLevel getOutputLevel() const {
     return Level;
   }

include/swift/Driver/Compilation.h

@@ -13,6 +13,7 @@
 #ifndef SWIFT_DRIVER_DEPENDENCYGRAPH_H
 #define SWIFT_DRIVER_DEPENDENCYGRAPH_H
 
+#include "swift/AST/DiagnosticEngine.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/OptionSet.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -121,7 +122,6 @@ class DependencyGraphImpl {
   llvm::StringMap<std::pair<std::vector<DependencyEntryTy>, DependencyMaskTy>> Dependencies;
 
   /// The set of marked nodes.
-
   llvm::SmallPtrSet<const void *, 16> Marked;
 
   /// A list of all external dependencies that cannot be resolved from just this
@@ -231,7 +231,10 @@ class DependencyGraph : public DependencyGraphImpl {
   /// ("depends") are not cleared; new dependencies are considered additive.
   ///
   /// If \p node has already been marked, only its outgoing edges are updated.
-  LoadResult loadFromPath(T node, StringRef path) {
+  /// The third argument is ignored here, but must be present so that the same
+  /// call site can polymorphically call \ref
+  /// experimental_dependencies::ModuleDepGraph::loadFromPath
+  LoadResult loadFromPath(T node, StringRef path, DiagnosticEngine &) {
     return DependencyGraphImpl::loadFromPath(Traits::getAsVoidPointer(node),
                                              path);
   }