[Stats] Reduce layering violations in FrontendStatsTracer.

include/swift/Basic/Statistic.h

@@ -13,7 +13,6 @@
 #ifndef SWIFT_BASIC_STATISTIC_H
 #define SWIFT_BASIC_STATISTIC_H
 
-#include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Statistic.h"
 #include "swift/AST/Identifier.h"
@@ -86,19 +85,29 @@ public:
     int dummyInstanceVariableToGetConstructorToParse;
   };
 
-  typedef llvm::PointerUnion4<const Decl*,
-                              const clang::Decl*,
-                              const Expr*,
-                              const SILFunction*> TraceEntity;
+  // To trace an entity, you have to provide a TraceFormatter for it. This is a
+  // separate type since we do not have retroactive conformances in C++, and it
+  // is a type that takes void* arguments since we do not have existentials
+  // separate from objects in C++. Pity us.
+  struct TraceFormatter {
+    virtual void traceName(const void *Entity, raw_ostream &OS) const = 0;
+    virtual void traceLoc(const void *Entity,
+                          SourceManager *SourceMgr,
+                          clang::SourceManager *ClangSourceMgr,
+                          raw_ostream &OS) const = 0;
+    virtual ~TraceFormatter();
+  };
 
   struct FrontendStatsTracer
   {
     UnifiedStatsReporter *Reporter;
     llvm::TimeRecord SavedTime;
     StringRef EventName;
-    TraceEntity Entity;
+    const void *Entity;
+    const TraceFormatter *Formatter;
     FrontendStatsTracer(StringRef EventName,
-                        TraceEntity Entity,
+                        const void *Entity,
+                        const TraceFormatter *Formatter,
                         UnifiedStatsReporter *Reporter);
     FrontendStatsTracer();
     FrontendStatsTracer(FrontendStatsTracer&& other);
@@ -117,7 +126,8 @@ public:
     StringRef CounterName;
     size_t CounterDelta;
     size_t CounterValue;
-    TraceEntity Entity;
+    const void *Entity;
+    const TraceFormatter *Formatter;
   };
 
 private:
@@ -162,9 +172,10 @@ public:
   AlwaysOnFrontendCounters &getFrontendCounters();
   AlwaysOnFrontendRecursiveSharedTimers &getFrontendRecursiveSharedTimers();
   void noteCurrentProcessExitStatus(int);
-  // We provide 4 explicit overloads here, rather than a single function that
-  // takes a TraceEntity, to save all of our clients from having to include all
-  // 4 headers that define these 4 forward-declared types.
+  // We declare 4 explicit overloads here, but the _definitions_ live in the
+  // upper-level files (in libswiftAST or libswiftSIL) that provide the types
+  // being traced. If you want to trace those types, it's assumed you're linking
+  // with the object files that define the tracer.
   FrontendStatsTracer getStatsTracer(StringRef EventName, const Decl *D);
   FrontendStatsTracer getStatsTracer(StringRef EventName, const clang::Decl*D);
   FrontendStatsTracer getStatsTracer(StringRef EventName, const Expr *E);

lib/AST/Decl.cpp

@@ -5658,3 +5658,37 @@ void Decl::setClangNode(ClangNode Node) {
   }
   *(ptr - 1) = Node.getOpaqueValue();
 }
+
+// See swift/Basic/Statistic.h for declaration: this enables tracing Decls, is
+// defined here to avoid too much layering violation / circular linkage
+// dependency.
+
+struct DeclTraceFormatter : public UnifiedStatsReporter::TraceFormatter {
+  void traceName(const void *Entity, raw_ostream &OS) const {
+    if (!Entity)
+      return;
+    const Decl *D = static_cast<const Decl *>(Entity);
+    if (auto const *VD = dyn_cast<const ValueDecl>(D)) {
+      VD->getFullName().print(OS, false);
+    }
+  }
+  void traceLoc(const void *Entity, SourceManager *SM,
+                clang::SourceManager *CSM, raw_ostream &OS) const {
+    if (!Entity)
+      return;
+    const Decl *D = static_cast<const Decl *>(Entity);
+    D->getSourceRange().print(OS, *SM, false);
+  }
+};
+
+static DeclTraceFormatter TF;
+
+UnifiedStatsReporter::FrontendStatsTracer
+UnifiedStatsReporter::getStatsTracer(StringRef EventName, const Decl *D) {
+  if (LastTracedFrontendCounters)
+    // Return live tracer object.
+    return FrontendStatsTracer(EventName, D, &TF, this);
+  else
+    // Return inert tracer object.
+    return FrontendStatsTracer();
+}

lib/AST/Expr.cpp

@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/AST/Expr.h"
+#include "swift/Basic/Statistic.h"
 #include "swift/Basic/Unicode.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/ASTVisitor.h"
@@ -2276,3 +2277,32 @@ void KeyPathExpr::Component::setSubscriptIndexHashableConformances(
     llvm_unreachable("no hashable conformances for this kind");
   }
 }
+
+// See swift/Basic/Statistic.h for declaration: this enables tracing Decls, is
+// defined here to avoid too much layering violation / circular linkage
+// dependency.
+
+struct ExprTraceFormatter : public UnifiedStatsReporter::TraceFormatter {
+  void traceName(const void *Entity, raw_ostream &OS) const {
+    // Exprs don't have names.
+  }
+  void traceLoc(const void *Entity, SourceManager *SM,
+                clang::SourceManager *CSM, raw_ostream &OS) const {
+    if (!Entity)
+      return;
+    const Expr *D = static_cast<const Expr *>(Entity);
+    D->getSourceRange().print(OS, *SM, false);
+  }
+};
+
+static ExprTraceFormatter TF;
+
+UnifiedStatsReporter::FrontendStatsTracer
+UnifiedStatsReporter::getStatsTracer(StringRef EventName, const Expr *E) {
+  if (LastTracedFrontendCounters)
+    // Return live tracer object.
+    return FrontendStatsTracer(EventName, E, &TF, this);
+  else
+    // Return inert tracer object.
+    return FrontendStatsTracer();
+}

lib/Basic/Statistic.cpp

@@ -260,19 +260,23 @@ UnifiedStatsReporter::printAlwaysOnStatsAndTimers(raw_ostream &OS) {
 
 UnifiedStatsReporter::FrontendStatsTracer::FrontendStatsTracer(
     StringRef EventName,
-    TraceEntity Entity,
+    const void *Entity,
+    const TraceFormatter *Formatter,
     UnifiedStatsReporter *Reporter)
   : Reporter(Reporter),
     SavedTime(llvm::TimeRecord::getCurrentTime()),
     EventName(EventName),
-    Entity(Entity)
+    Entity(Entity),
+    Formatter(Formatter)
 {
   if (Reporter)
     Reporter->saveAnyFrontendStatsEvents(*this, true);
 }
 
 UnifiedStatsReporter::FrontendStatsTracer::FrontendStatsTracer()
-  : Reporter(nullptr)
+  : Reporter(nullptr),
+    Entity(nullptr),
+    Formatter(nullptr)
 {
 }
 
@@ -284,6 +288,7 @@ UnifiedStatsReporter::FrontendStatsTracer::operator=(
   SavedTime = other.SavedTime;
   EventName = other.EventName;
   Entity = other.Entity;
+  Formatter = other.Formatter;
   other.Reporter = nullptr;
   return *this;
 }
@@ -293,7 +298,8 @@ UnifiedStatsReporter::FrontendStatsTracer::FrontendStatsTracer(
   : Reporter(other.Reporter),
     SavedTime(other.SavedTime),
     EventName(other.EventName),
-    Entity(other.Entity)
+    Entity(other.Entity),
+    Formatter(other.Formatter)
 {
   other.Reporter = nullptr;
 }
@@ -304,47 +310,6 @@ UnifiedStatsReporter::FrontendStatsTracer::~FrontendStatsTracer()
     Reporter->saveAnyFrontendStatsEvents(*this, false);
 }
 
-UnifiedStatsReporter::FrontendStatsTracer
-UnifiedStatsReporter::getStatsTracer(StringRef EventName,
-                                     const Decl *D)
-{
-  if (LastTracedFrontendCounters)
-    // Return live tracer object.
-    return FrontendStatsTracer(EventName, D, this);
-  else
-    // Return inert tracer object.
-    return FrontendStatsTracer();
-}
-
-UnifiedStatsReporter::FrontendStatsTracer
-UnifiedStatsReporter::getStatsTracer(StringRef EventName,
-                                     const Expr *E) {
-  if (LastTracedFrontendCounters)
-    return FrontendStatsTracer(EventName, E, this);
-  else
-    return FrontendStatsTracer();
-}
-
-UnifiedStatsReporter::FrontendStatsTracer
-UnifiedStatsReporter::getStatsTracer(StringRef EventName,
-                                     const clang::Decl *D)
-{
-  if (LastTracedFrontendCounters)
-    return FrontendStatsTracer(EventName, D, this);
-  else
-    return FrontendStatsTracer();
-}
-
-UnifiedStatsReporter::FrontendStatsTracer
-UnifiedStatsReporter::getStatsTracer(StringRef EventName,
-                                     const SILFunction *F)
-{
-  if (LastTracedFrontendCounters)
-    return FrontendStatsTracer(EventName, F, this);
-  else
-    return FrontendStatsTracer();
-}
-
 void
 UnifiedStatsReporter::saveAnyFrontendStatsEvents(
     FrontendStatsTracer const& T,
@@ -366,7 +331,7 @@ UnifiedStatsReporter::saveAnyFrontendStatsEvents(
       LastTracedFrontendCounters->NAME = C.NAME;              \
       FrontendStatsEvents.emplace_back(FrontendStatsEvent {   \
           NowUS, LiveUS, IsEntry, T.EventName, name,          \
-            delta, total, T.Entity});                         \
+            delta, total, T.Entity, T.Formatter});            \
     }                                                         \
   } while (0);
 #include "swift/Basic/Statistics.def"
@@ -382,56 +347,7 @@ UnifiedStatsReporter::AlwaysOnFrontendRecursiveSharedTimers::
       dummyInstanceVariableToGetConstructorToParse(0) {
 }
 
-static inline void
-printTraceEntityName(raw_ostream &OS,
-                     UnifiedStatsReporter::TraceEntity E) {
-  if (auto const *CD = E.dyn_cast<const clang::Decl*>()) {
-    if (auto const *ND = dyn_cast<const clang::NamedDecl>(CD)) {
-      ND->printName(OS);
-    }
-  } else if (auto const *D = E.dyn_cast<const Decl*>()) {
-    if (auto const *VD = dyn_cast<const ValueDecl>(D)) {
-      VD->getFullName().print(OS, false);
-    }
-  } else if (auto const *X = E.dyn_cast<const Expr*>()) {
-    // Exprs don't have names
-  } else if (auto const *F = E.dyn_cast<const SILFunction*>()) {
-    OS << F->getName();
-  }
-}
-
-static inline void
-printClangShortLoc(raw_ostream &OS,
-                   clang::SourceManager *CSM,
-                   clang::SourceLocation L) {
-  if (!L.isValid() || !L.isFileID())
-    return;
-  auto PLoc = CSM->getPresumedLoc(L);
-  OS << llvm::sys::path::filename(PLoc.getFilename())
-     << ':' << PLoc.getLine()
-     << ':' << PLoc.getColumn();
-}
-
-static inline void
-printTraceEntityLoc(raw_ostream &OS,
-                    SourceManager *SM,
-                    clang::SourceManager *CSM,
-                    UnifiedStatsReporter::TraceEntity E) {
-  if (auto const *CD = E.dyn_cast<const clang::Decl*>()) {
-    if (CSM) {
-      auto Range = CD->getSourceRange();
-      printClangShortLoc(OS, CSM, Range.getBegin());
-      OS << '-';
-      printClangShortLoc(OS, CSM, Range.getEnd());
-    }
-  } else if (auto const *D = E.dyn_cast<const Decl*>()) {
-    D->getSourceRange().print(OS, *SM, false);
-  } else if (auto const *X = E.dyn_cast<const Expr*>()) {
-    X->getSourceRange().print(OS, *SM, false);
-  } else if (auto const *F = E.dyn_cast<const SILFunction*>()) {
-    F->getLocation().getSourceRange().print(OS, *SM, false);
-  }
-}
+UnifiedStatsReporter::TraceFormatter::~TraceFormatter() {}
 
 UnifiedStatsReporter::~UnifiedStatsReporter()
 {
@@ -519,10 +435,12 @@ UnifiedStatsReporter::~UnifiedStatsReporter()
               << E.CounterDelta << ','
               << E.CounterValue << ',';
       tstream << '"';
-      printTraceEntityName(tstream, E.Entity);
+      if (E.Formatter)
+        E.Formatter->traceName(E.Entity, tstream);
       tstream << '"' << ',';
       tstream << '"';
-      printTraceEntityLoc(tstream, SourceMgr, ClangSourceMgr, E.Entity);
+      if (E.Formatter)
+        E.Formatter->traceLoc(E.Entity, SourceMgr, ClangSourceMgr, tstream);
       tstream << '"' << '\n';
     }
   }

lib/ClangImporter/ImportDecl.cpp

@@ -8585,3 +8585,53 @@ ClangImporter::getEnumConstantName(const clang::EnumConstantDecl *enumConstant){
       .getBaseIdentifier();
 }
 
+// See swift/Basic/Statistic.h for declaration: this enables tracing
+// clang::Decls, is defined here to avoid too much layering violation / circular
+// linkage dependency.
+
+struct ClangDeclTraceFormatter : public UnifiedStatsReporter::TraceFormatter {
+  void traceName(const void *Entity, raw_ostream &OS) const {
+    if (!Entity)
+      return;
+    const clang::Decl *CD = static_cast<const clang::Decl *>(Entity);
+    if (auto const *ND = dyn_cast<const clang::NamedDecl>(CD)) {
+      ND->printName(OS);
+    }
+  }
+
+  static inline void printClangShortLoc(raw_ostream &OS,
+                                        clang::SourceManager *CSM,
+                                        clang::SourceLocation L) {
+    if (!L.isValid() || !L.isFileID())
+      return;
+    auto PLoc = CSM->getPresumedLoc(L);
+    OS << llvm::sys::path::filename(PLoc.getFilename()) << ':' << PLoc.getLine()
+       << ':' << PLoc.getColumn();
+  }
+
+  void traceLoc(const void *Entity, SourceManager *SM,
+                clang::SourceManager *CSM, raw_ostream &OS) const {
+    if (!Entity)
+      return;
+    if (CSM) {
+      const clang::Decl *CD = static_cast<const clang::Decl *>(Entity);
+      auto Range = CD->getSourceRange();
+      printClangShortLoc(OS, CSM, Range.getBegin());
+      OS << '-';
+      printClangShortLoc(OS, CSM, Range.getEnd());
+    }
+  }
+};
+
+static ClangDeclTraceFormatter TF;
+
+UnifiedStatsReporter::FrontendStatsTracer
+UnifiedStatsReporter::getStatsTracer(StringRef EventName,
+                                     const clang::Decl *D) {
+  if (LastTracedFrontendCounters)
+    // Return live tracer object.
+    return FrontendStatsTracer(EventName, D, &TF, this);
+  else
+    // Return inert tracer object.
+    return FrontendStatsTracer();
+}

lib/SIL/SILFunction.cpp

@@ -19,6 +19,7 @@
 #include "swift/SIL/PrettyStackTrace.h"
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/Basic/OptimizationMode.h"
+#include "swift/Basic/Statistic.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/GraphWriter.h"
@@ -490,3 +491,37 @@ SubstitutionList SILFunction::getForwardingSubstitutions() {
 bool SILFunction::shouldVerifyOwnership() const {
   return !hasSemanticsAttr("verify.ownership.sil.never");
 }
+
+// See swift/Basic/Statistic.h for declaration: this enables tracing
+// SILFunctions, is defined here to avoid too much layering violation / circular
+// linkage dependency.
+
+struct SILFunctionTraceFormatter : public UnifiedStatsReporter::TraceFormatter {
+  void traceName(const void *Entity, raw_ostream &OS) const {
+    if (!Entity)
+      return;
+    const SILFunction *F = static_cast<const SILFunction *>(Entity);
+    OS << F->getName();
+  }
+
+  void traceLoc(const void *Entity, SourceManager *SM,
+                clang::SourceManager *CSM, raw_ostream &OS) const {
+    if (!Entity)
+      return;
+    const SILFunction *F = static_cast<const SILFunction *>(Entity);
+    F->getLocation().getSourceRange().print(OS, *SM, false);
+  }
+};
+
+static SILFunctionTraceFormatter TF;
+
+UnifiedStatsReporter::FrontendStatsTracer
+UnifiedStatsReporter::getStatsTracer(StringRef EventName,
+                                     const SILFunction *F) {
+  if (LastTracedFrontendCounters)
+    // Return live tracer object.
+    return FrontendStatsTracer(EventName, F, &TF, this);
+  else
+    // Return inert tracer object.
+    return FrontendStatsTracer();
+}

test/Misc/stats_dir_tracer.swift

@@ -0,0 +1,9 @@
+// RUN: rm -rf %t && mkdir -p %t
+// RUN: %target-swiftc_driver -o %t/main -module-name main -stats-output-dir %t %s -trace-stats-events
+// RUN: %FileCheck -input-file %t/*.csv %s
+
+// CHECK: {{"Sema.NumTypesDeserialized"}}
+
+public func foo() {
+    print("hello")
+}