[Coverage] Do not emit increments in certain implicitly-generated reg…

lib/SILGen/SILGenFunction.h

@@ -465,7 +465,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
 
   /// Emit code to increment a counter for profiling.
   void emitProfilerIncrement(ASTNode N) {
-    if (SGM.Profiler)
+    if (SGM.Profiler && SGM.Profiler->hasRegionCounters())
       SGM.Profiler->emitCounterIncrement(B, N);
   }
 

lib/SILGen/SILGenProfiling.cpp

@@ -29,17 +29,24 @@
 using namespace swift;
 using namespace Lowering;
 
+static bool isUnmappedDecl(Decl *D) {
+  if (isa<ConstructorDecl>(D) || isa<DestructorDecl>(D))
+    return false;
+
+  return D->isImplicit() || isa<EnumCaseDecl>(D);
+}
+
 ProfilerRAII::ProfilerRAII(SILGenModule &SGM, AbstractFunctionDecl *D)
-    : SGM(SGM) {
+    : SGM(SGM), PreviousProfiler(std::move(SGM.Profiler)) {
   const auto &Opts = SGM.M.getOptions();
-  if (!Opts.GenerateProfile)
+  if (!Opts.GenerateProfile || isUnmappedDecl(D))
     return;
   SGM.Profiler =
       llvm::make_unique<SILGenProfiling>(SGM, Opts.EmitProfileCoverageMapping);
   SGM.Profiler->assignRegionCounters(D);
 }
 
-ProfilerRAII::~ProfilerRAII() { SGM.Profiler = nullptr; }
+ProfilerRAII::~ProfilerRAII() { SGM.Profiler = std::move(PreviousProfiler); }
 
 namespace {
 
@@ -55,6 +62,8 @@ struct MapRegionCounters : public ASTWalker {
       : NextCounter(0), CounterMap(CounterMap) {}
 
   bool walkToDeclPre(Decl *D) override {
+    if (isUnmappedDecl(D))
+      return false;
     if (auto *AFD = dyn_cast<AbstractFunctionDecl>(D))
       CounterMap[AFD->getBody()] = NextCounter++;
     return true;
@@ -435,7 +444,7 @@ struct CoverageMapping : public ASTWalker {
   }
 
   bool walkToDeclPre(Decl *D) override {
-    if (D->isImplicit())
+    if (isUnmappedDecl(D))
       return false;
     if (auto *AFD = dyn_cast<AbstractFunctionDecl>(D))
       assignCounter(AFD->getBody());

lib/SILGen/SILGenProfiling.h

@@ -27,12 +27,7 @@ namespace Lowering {
 class SILGenModule;
 class SILGenBuilder;
 
-/// RAII object to set up profiling for a function.
-struct ProfilerRAII {
-  SILGenModule &SGM;
-  ProfilerRAII(SILGenModule &SGM, AbstractFunctionDecl *D);
-  ~ProfilerRAII();
-};
+struct ProfilerRAII;
 
 /// Profiling state.
 class SILGenProfiling {
@@ -57,11 +52,23 @@ class SILGenProfiling {
 
   bool hasRegionCounters() const { return NumRegionCounters != 0; }
 
+  /// Emit SIL to increment the counter for \c Node.
+  void emitCounterIncrement(SILGenBuilder &Builder, ASTNode Node);
+
+private:
   /// Map counters to ASTNodes and set them up for profiling the given function.
   void assignRegionCounters(AbstractFunctionDecl *Root);
 
-  /// Emit SIL to increment the counter for \c Node.
-  void emitCounterIncrement(SILGenBuilder &Builder, ASTNode Node);
+  friend struct ProfilerRAII;
+};
+
+/// RAII object to set up profiling for a function.
+struct ProfilerRAII {
+  SILGenModule &SGM;
+  std::unique_ptr<SILGenProfiling> PreviousProfiler;
+
+  ProfilerRAII(SILGenModule &SGM, AbstractFunctionDecl *D);
+  ~ProfilerRAII();
 };
 
 } // end namespace Lowering

test/SILGen/coverage_smoke.swift

@@ -53,4 +53,15 @@ func main() {
   let _ = Class1()
 }
 
+// rdar://problem/22761498 - enum declaration suppresses coverage
+func foo() {
+  var x : Int32 = 0   // CHECK-COV: 1|{{.*}}[[@LINE]]
+  enum ETy { case A } // CHECK-COV: 1|{{.*}}[[@LINE]]
+  repeat {            // CHECK-COV: 1|{{.*}}[[@LINE]]
+    x += 1            // CHECK-COV: 1|{{.*}}[[@LINE]]
+  } while x == 0      // CHECK-COV: 1|{{.*}}[[@LINE]]
+  x += 1              // CHECK-COV: 1|{{.*}}[[@LINE]]
+}
+
 main()
+foo()