<rdar://problem/20402026> Remove scope entry/exit log entries

Don't emit scope entry/exit logging code in instrumentation for
playgrounds if -playground-high-performance option is passed.

Swift SVN r27046

include/swift/Frontend/FrontendOptions.h

@@ -196,6 +196,10 @@ public:
   /// Indicates whether the playground transformation should be applied.
   bool PlaygroundTransform = false;
 
+  /// Indicates whether the playground transformation should omit
+  /// instrumentation that has a high runtime performance impact.
+  bool PlaygroundHighPerformance = false;
+
   /// Indicates whether standard help should be shown.
   bool PrintHelp = false;
 

include/swift/Option/FrontendOptions.td

@@ -209,6 +209,9 @@ def print_stats : Flag<["-"], "print-stats">,
 def playground : Flag<["-"], "playground">,
   HelpText<"Apply the playground semantics and transformation">;
 
+def playground_high_performance : Flag<["-"], "playground-high-performance">,
+  HelpText<"Omit instrumentation that has a high runtime performance impact">;
+
 def disable_playground_transform : Flag<["-"], "disable-playground-transform">,
   HelpText<"Disable playground transformation">;
 

include/swift/Subsystems.h

@@ -133,7 +133,10 @@ namespace swift {
 
   /// Once parsing and name-binding are complete, this optionally transforms the
   /// ASTs to add calls to external logging functions.
-  void performPlaygroundTransform(SourceFile &SF);
+  ///
+  /// \param HighPerformance True if the playground transform should omit
+  /// instrumentation that has a high runtime performance impact.
+  void performPlaygroundTransform(SourceFile &SF, bool HighPerformance);
   
   /// Flags used to control type checking.
   enum class TypeCheckingFlags : unsigned {

lib/Frontend/CompilerInvocation.cpp

@@ -112,6 +112,8 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
   Opts.PlaygroundTransform |= Args.hasArg(OPT_playground);
   if (Args.hasArg(OPT_disable_playground_transform))
     Opts.PlaygroundTransform = false;
+  Opts.PlaygroundHighPerformance |=
+    Args.hasArg(OPT_playground_high_performance);
 
   if (const Arg *A = Args.getLastArg(OPT_help, OPT_help_hidden)) {
     if (A->getOption().matches(OPT_help)) {

lib/Frontend/Frontend.cpp

@@ -425,7 +425,7 @@ void CompilerInstance::performSema() {
     } while (!Done);
     
     if (mainIsPrimary && Invocation.getFrontendOptions().PlaygroundTransform)
-      performPlaygroundTransform(MainFile);
+      performPlaygroundTransform(MainFile, Invocation.getFrontendOptions().PlaygroundHighPerformance);
     if (!mainIsPrimary)
       performNameBinding(MainFile);
   }

lib/Sema/PlaygroundTransform.cpp

@@ -45,6 +45,7 @@ private:
   ASTContext &Context;
   DeclContext *TypeCheckDC;
   unsigned TmpNameIndex = 0;
+  bool HighPerformance;
 
   struct BracePair {
   public:
@@ -110,6 +111,9 @@ private:
   // all the braces up to its target.
   size_t escapeToTarget(BracePair::TargetKinds TargetKind,
                         ElementVector &Elements, size_t EI) {
+    if (HighPerformance)
+      return EI;
+
     for (const BracePair &BP : BracePairs) {
       if (BP.TargetKind == TargetKind) {
         break;
@@ -151,8 +155,9 @@ private:
   ClosureFinder CF;
 
 public:
-  Instrumenter (ASTContext &C, DeclContext *DC, std::mt19937_64 &RNG) :
-    RNG(RNG), Context(C), TypeCheckDC(DC), CF(*this) { }
+  Instrumenter (ASTContext &C, DeclContext *DC, std::mt19937_64 &RNG,
+                bool HP) :
+    RNG(RNG), Context(C), TypeCheckDC(DC), HighPerformance(HP), CF(*this) { }
     
   Stmt *transformStmt(Stmt *S) { 
     switch (S->getKind()) {
@@ -558,7 +563,7 @@ public:
       }
     }
 
-    if (!TopLevel) {
+    if (!TopLevel && !HighPerformance) {
       Elements.insert(Elements.begin(), buildScopeEntry(BS->getSourceRange()));
       Elements.insert(Elements.end(), buildScopeExit(BS->getSourceRange()));
     }
@@ -579,7 +584,8 @@ public:
   }
 
   // log*() functions return a newly-created log expression to be inserted
-  // after or instead of the expression they're looking at.
+  // after or instead of the expression they're looking at.  Only call this
+  // if the variable has an initializer.
   Expr *logVarDecl(VarDecl *VD) {
     if (llvm::dyn_cast<ConstructorDecl>(TypeCheckDC) &&
         VD->getNameStr().equals("self")) {
@@ -812,16 +818,20 @@ public:
 
 } // end anonymous namespace
 
-void swift::performPlaygroundTransform(SourceFile &SF) {
+void swift::performPlaygroundTransform(SourceFile &SF,
+                                       bool HighPerformance) {
   class ExpressionFinder : public ASTWalker {
   private:
     std::mt19937_64 RNG;
+    bool HighPerformance;
   public:
+    ExpressionFinder(bool HP) : HighPerformance(HP) { }
+
     virtual bool walkToDeclPre(Decl *D) {
       if (AbstractFunctionDecl *FD = llvm::dyn_cast<AbstractFunctionDecl>(D)) {
         if (!FD->isImplicit()) {
           if (BraceStmt *Body = FD->getBody()) {
-            Instrumenter I(FD->getASTContext(), FD, RNG);
+            Instrumenter I(FD->getASTContext(), FD, RNG, HighPerformance);
             BraceStmt *NewBody = I.transformBraceStmt(Body);
             if (NewBody != Body) {
               FD->setBody(NewBody);
@@ -832,7 +842,7 @@ void swift::performPlaygroundTransform(SourceFile &SF) {
       } else if (TopLevelCodeDecl *TLCD = llvm::dyn_cast<TopLevelCodeDecl>(D)) {
         if (!TLCD->isImplicit()) {
           if (BraceStmt *Body = TLCD->getBody()) {
-            Instrumenter I(((Decl*)TLCD)->getASTContext(), TLCD, RNG);
+            Instrumenter I(((Decl*)TLCD)->getASTContext(), TLCD, RNG, HighPerformance);
             BraceStmt *NewBody = I.transformBraceStmt(Body, true);
             if (NewBody != Body) {
               TLCD->setBody(NewBody);
@@ -845,7 +855,7 @@ void swift::performPlaygroundTransform(SourceFile &SF) {
     }
   };
 
-  ExpressionFinder EF;
+  ExpressionFinder EF(HighPerformance);
   for (Decl* D : SF.Decls) {
     D->walk(EF);
   }

test/PlaygroundTransform/high_performance.swift

@@ -0,0 +1,39 @@
+// RUN: rm -rf %t
+// RUN: mkdir %t
+// RUN: cp %s %t/main.swift
+// RUN: %target-build-swift -Xfrontend -playground -Xfrontend -playground-high-performance -Xfrontend -debugger-support -o %t/main %S/Inputs/PlaygroundsRuntime.swift %t/main.swift
+// RUN: %target-run %t/main | FileCheck %s
+
+var a = true
+if (a) {
+  5
+} else {
+  7
+}
+
+for i in 0..<3 {
+  i
+}
+// CHECK: [{{.*}}] $builtin_log[a='true']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='5']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='0']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='1']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='2']
+
+var b = true
+for i in 0..<3 {
+  i
+  continue
+}
+// CHECK-NEXT: [{{.*}}] $builtin_log[b='true']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='0']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='1']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='2']
+
+var c = true
+for i in 0..<3 {
+  i
+  break
+}
+// CHECK-NEXT: [{{.*}}] $builtin_log[c='true']
+// CHECK-NEXT: [{{.*}}] $builtin_log[='0']