RequirementMachine: Add histograms for symbol kinds and term length

Author: slavapestov

lib/AST/RequirementMachine/RewriteContext.cpp

@@ -19,6 +19,13 @@
 using namespace swift;
 using namespace rewriting;
 
+RewriteContext::RewriteContext(ASTContext &ctx)
+    : Context(ctx),
+      Stats(ctx.Stats),
+      SymbolHistogram(Symbol::NumKinds),
+      TermHistogram(4, /*Start=*/1) {
+}
+
 Term RewriteContext::getTermForType(CanType paramType,
                                     const ProtocolDecl *proto) {
   return Term::get(getMutableTermForType(paramType, proto), *this);
@@ -271,4 +278,16 @@ Type RewriteContext::getRelativeTypeForTerm(
   return getTypeForSymbolRange(
       term.begin() + prefix.size(), term.end(), genericParam,
       { }, protos, Context);
+}
+
+/// We print stats in the destructor, which should get executed at the end of
+/// a compilation job.
+RewriteContext::~RewriteContext() {
+  if (Context.LangOpts.AnalyzeRequirementMachine) {
+    llvm::dbgs() << "--- Requirement Machine Statistics ---\n";
+    llvm::dbgs() << "\n* Symbol kind:\n";
+    SymbolHistogram.dump(llvm::dbgs(), Symbol::Kinds);
+    llvm::dbgs() << "\n* Term length:\n";
+    TermHistogram.dump(llvm::dbgs());
+  }
 }

lib/AST/RequirementMachine/RewriteContext.h

@@ -18,7 +18,9 @@
 #include "swift/Basic/Statistic.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/Support/Allocator.h"
-#include "RewriteSystem.h"
+#include "Histogram.h"
+#include "Symbol.h"
+#include "Term.h"
 
 namespace swift {
 
@@ -50,10 +52,14 @@ class RewriteContext final {
   ASTContext &Context;
 
 public:
-  /// Statistical counters.
+  /// Statistics.
   UnifiedStatsReporter *Stats;
 
-  RewriteContext(ASTContext &ctx) : Context(ctx), Stats(ctx.Stats) {}
+  /// Histograms.
+  Histogram SymbolHistogram;
+  Histogram TermHistogram;
+
+  explicit RewriteContext(ASTContext &ctx);
 
   Term getTermForType(CanType paramType, const ProtocolDecl *proto);
 
@@ -73,6 +79,8 @@ class RewriteContext final {
   Type getRelativeTypeForTerm(
                       const MutableTerm &term, const MutableTerm &prefix,
                       const ProtocolGraph &protos) const;
+
+  ~RewriteContext();
 };
 
 } // end namespace rewriting

lib/AST/RequirementMachine/RewriteSystem.cpp

@@ -23,6 +23,14 @@
 using namespace swift;
 using namespace rewriting;
 
+RewriteSystem::RewriteSystem(RewriteContext &ctx)
+    : Context(ctx) {
+  DebugSimplify = false;
+  DebugAdd = false;
+  DebugMerge = false;
+  DebugCompletion = false;
+}
+
 void Rule::dump(llvm::raw_ostream &out) const {
   out << LHS << " => " << RHS;
   if (deleted)

lib/AST/RequirementMachine/RewriteSystem.h

@@ -134,12 +134,7 @@ class RewriteSystem final {
   unsigned DebugCompletion : 1;
 
 public:
-  explicit RewriteSystem(RewriteContext &ctx) : Context(ctx) {
-    DebugSimplify = false;
-    DebugAdd = false;
-    DebugMerge = false;
-    DebugCompletion = false;
-  }
+  explicit RewriteSystem(RewriteContext &ctx);
 
   RewriteSystem(const RewriteSystem &) = delete;
   RewriteSystem(RewriteSystem &&) = delete;

lib/AST/RequirementMachine/Symbol.cpp

@@ -24,6 +24,16 @@
 using namespace swift;
 using namespace rewriting;
 
+const StringRef Symbol::Kinds[] = {
+  "protocol",
+  "assocty",
+  "generic",
+  "name",
+  "layout",
+  "super",
+  "concrete"
+};
+
 /// Symbols are uniqued and immutable, stored as a single pointer;
 /// the Storage type is the allocated backing storage.
 struct Symbol::Storage final
@@ -209,6 +219,7 @@ Symbol Symbol::forName(Identifier name,
 #endif
 
   ctx.Symbols.InsertNode(symbol, insertPos);
+  ctx.SymbolHistogram.add(unsigned(Kind::Name));
 
   return symbol;
 }
@@ -237,6 +248,7 @@ Symbol Symbol::forProtocol(const ProtocolDecl *proto,
 #endif
 
   ctx.Symbols.InsertNode(symbol, insertPos);
+  ctx.SymbolHistogram.add(unsigned(Kind::Protocol));
 
   return symbol;
 }
@@ -280,6 +292,7 @@ Symbol Symbol::forAssociatedType(ArrayRef<const ProtocolDecl *> protos,
 #endif
 
   ctx.Symbols.InsertNode(symbol, insertPos);
+  ctx.SymbolHistogram.add(unsigned(Kind::AssociatedType));
 
   return symbol;
 }
@@ -310,6 +323,7 @@ Symbol Symbol::forGenericParam(GenericTypeParamType *param,
 #endif
 
   ctx.Symbols.InsertNode(symbol, insertPos);
+  ctx.SymbolHistogram.add(unsigned(Kind::GenericParam));
 
   return symbol;
 }
@@ -336,6 +350,7 @@ Symbol Symbol::forLayout(LayoutConstraint layout,
 #endif
 
   ctx.Symbols.InsertNode(symbol, insertPos);
+  ctx.SymbolHistogram.add(unsigned(Kind::Layout));
 
   return symbol;
 }
@@ -367,6 +382,7 @@ Symbol Symbol::forSuperclass(CanType type, ArrayRef<Term> substitutions,
 #endif
 
   ctx.Symbols.InsertNode(symbol, insertPos);
+  ctx.SymbolHistogram.add(unsigned(Kind::Superclass));
 
   return symbol;
 }
@@ -397,6 +413,7 @@ Symbol Symbol::forConcreteType(CanType type, ArrayRef<Term> substitutions,
 #endif
 
   ctx.Symbols.InsertNode(symbol, insertPos);
+  ctx.SymbolHistogram.add(unsigned(Kind::ConcreteType));
 
   return symbol;
 }

lib/AST/RequirementMachine/Symbol.h

@@ -109,6 +109,10 @@ class Symbol final {
     ConcreteType,
   };
 
+  static const unsigned NumKinds = 7;
+
+  static const StringRef Kinds[];
+
 private:
   friend class RewriteContext;
 

lib/AST/RequirementMachine/Term.cpp

@@ -101,6 +101,7 @@ Term Term::get(const MutableTerm &mutableTerm, RewriteContext &ctx) {
     term->getElements()[i] = mutableTerm[i];
 
   ctx.Terms.InsertNode(term, insertPos);
+  ctx.TermHistogram.add(size);
 
   return term;
 }