Basic: Add -analyze-request-evaluator flag to dump request cache statistics

Author: slavapestov

include/swift/AST/Evaluator.h

@@ -283,6 +283,8 @@ class Evaluator {
     return activeRequests.count(ActiveRequest(request));
   }
 
+  void dump(llvm::raw_ostream &out) { cache.dump(out); }
+
 private:
   /// Diagnose a cycle detected in the evaluation of the given
   /// request.

include/swift/AST/RequestCache.h

@@ -18,6 +18,7 @@
 #include "swift/AST/DependencyCollector.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/raw_ostream.h"
 
 #ifndef SWIFT_AST_REQUEST_CACHE_H
 #define SWIFT_AST_REQUEST_CACHE_H
@@ -162,14 +163,22 @@ class RequestKey<Request, typename detail::TupleHasDenseMapInfo<
 class PerRequestCache {
   void *Storage;
   std::function<void(void *)> Deleter;
+  std::function<void(llvm::raw_ostream &out, void *)> Dumper;
 
-  PerRequestCache(void *storage, std::function<void(void *)> deleter)
-      : Storage(storage), Deleter(deleter) {}
+  PerRequestCache(void *storage,
+                  std::function<void(void *)> deleter,
+                  std::function<void(llvm::raw_ostream &out, void *)> dumper)
+      : Storage(storage), Deleter(deleter), Dumper(dumper) {}
 
 public:
-  PerRequestCache() : Storage(nullptr), Deleter([](void *) {}) {}
+  PerRequestCache()
+    : Storage(nullptr),
+      Deleter([](void *) {}),
+      Dumper([](llvm::raw_ostream &, void *) {}) {}
   PerRequestCache(PerRequestCache &&other)
-      : Storage(other.Storage), Deleter(std::move(other.Deleter)) {
+      : Storage(other.Storage),
+        Deleter(std::move(other.Deleter)),
+        Dumper(std::move(other.Dumper)) {
     other.Storage = nullptr;
   }
 
@@ -190,7 +199,17 @@ class PerRequestCache {
         llvm::DenseMap<RequestKey<Request>,
                        typename Request::OutputType>;
     return PerRequestCache(new Map(),
-                           [](void *ptr) { delete static_cast<Map *>(ptr); });
+                           [](void *ptr) { delete static_cast<Map *>(ptr); },
+                           [](llvm::raw_ostream &out, void *storage) {
+                             out << TypeID<Request>::getName() << "\t";
+                             if (auto *map = static_cast<Map *>(storage)) {
+                               out << map->size() << "\t"
+                                   << llvm::capacity_in_bytes(*map);
+                             } else {
+                               out << "0\t0";
+                             }
+                             out << "\n";
+                           });
   }
 
   template <typename Request>
@@ -204,11 +223,28 @@ class PerRequestCache {
     return static_cast<Map *>(Storage);
   }
 
+  template <typename Request>
+  std::pair<size_t, size_t>
+  size() const {
+    using Map =
+        llvm::DenseMap<RequestKey<Request>,
+                       typename Request::OutputType>;
+    if (!Storage)
+      return std::make_pair(0, 0);
+
+    auto map = static_cast<Map *>(Storage);
+    return std::make_pair(map.size(), llvm::capacity_in_bytes(map));
+  }
+
   bool isNull() const { return !Storage; }
   ~PerRequestCache() {
     if (Storage)
       Deleter(Storage);
   }
+
+  void dump(llvm::raw_ostream &out) {
+    Dumper(out, Storage);
+  }
 };
 
 /// Data structure for caching results of requests. Sharded by the type ID
@@ -275,6 +311,15 @@ class RequestCache {
   void clear() {
 #define SWIFT_TYPEID_ZONE(Name, Id) Name##ZoneCache.clear();
 #include "swift/Basic/TypeIDZones.def"
+#undef SWIFT_TYPEID_ZONE
+  }
+
+  void dump(llvm::raw_ostream &out) {
+#define SWIFT_TYPEID_ZONE(Name, Id)                                            \
+    for (auto &entry : Name##ZoneCache) {                                      \
+      entry.dump(out);                                                         \
+    }
+#include "swift/Basic/TypeIDZones.def"
 #undef SWIFT_TYPEID_ZONE
   }
 };

include/swift/Basic/LangOptions.h

@@ -531,6 +531,9 @@ namespace swift {
     ASTVerifierOverrideKind ASTVerifierOverride =
         ASTVerifierOverrideKind::NoOverride;
 
+    /// Dumps request evaluator cache statistics at the end of compilation.
+    bool AnalyzeRequestEvaluator = false;
+
     /// Enables dumping rewrite systems from the requirement machine.
     bool DumpRequirementMachine = false;
 

include/swift/Option/FrontendOptions.td

@@ -415,6 +415,10 @@ def dump_macro_expansions : Flag<["-"], "dump-macro-expansions">,
 def emit_macro_expansion_files : Separate<["-"], "emit-macro-expansion-files">,
   HelpText<"Specify when to emit macro expansion file: 'none', 'debug', or 'diagnostics'">;
 
+def analyze_request_evaluator : Flag<["-"], "analyze-request-evaluator">,
+  Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
+  HelpText<"Print out request evaluator cache statistics at the end of the compilation job">;
+
 def analyze_requirement_machine : Flag<["-"], "analyze-requirement-machine">,
   Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
   HelpText<"Print out requirement machine statistics at the end of the compilation job">;

lib/AST/ASTContext.cpp

@@ -804,6 +804,8 @@ ASTContext::ASTContext(
 }
 
 ASTContext::~ASTContext() {
+  if (LangOpts.AnalyzeRequestEvaluator)
+    evaluator.dump(llvm::dbgs());
   getImpl().~Implementation();
 }
 

lib/Frontend/CompilerInvocation.cpp

@@ -1472,6 +1472,9 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.DisableSubstSILFunctionTypes =
       Args.hasArg(OPT_disable_subst_sil_function_types);
 
+  Opts.AnalyzeRequestEvaluator = Args.hasArg(
+      OPT_analyze_request_evaluator);
+
   Opts.DumpRequirementMachine = Args.hasArg(
       OPT_dump_requirement_machine);
   Opts.AnalyzeRequirementMachine = Args.hasArg(