[Profiler] Avoid recording empty regions

These are redundant.

Author: hamishknight

lib/SIL/IR/SILProfiler.cpp

@@ -582,6 +582,11 @@ class SourceMappingRegion {
     return *EndLoc;
   }
 
+  /// Whether the region has a non-empty range.
+  bool hasNonEmptyRange() const {
+    return StartLoc && EndLoc && *StartLoc != *EndLoc;
+  }
+
   void print(llvm::raw_ostream &OS, const SourceManager &SM) const {
     OS << "[";
     if (hasStartLoc())
@@ -1006,6 +1011,7 @@ struct CoverageMapping : public ASTWalker {
     assert(I != E && "parent not in stack");
     auto ParentIt = I;
     SourceLoc EndLoc = ParentIt->getEndLoc();
+    assert(ParentIt->hasNonEmptyRange() && "Pushed node with empty range?");
 
     unsigned FirstPoppedIndex = SourceRegions.size();
     (void)FirstPoppedIndex;
@@ -1015,6 +1021,12 @@ struct CoverageMapping : public ASTWalker {
         continue;
       if (!I->hasEndLoc())
         I->setEndLoc(EndLoc);
+
+      // If the range ended up being empty, ignore it (this can happen when we
+      // replace the counter, and don't extend the region any further).
+      if (!I->hasNonEmptyRange())
+        continue;
+
       SourceRegions.push_back(std::move(*I));
     }
 

test/Profiler/coverage_switch.swift

@@ -51,17 +51,18 @@ enum Algebraic {
 func nop() {}
 
 // CHECK-LABEL: sil_coverage_map {{.*}}// coverage_switch.f2
-func f2(_ x : Algebraic) -> Int32 { // CHECK-NEXT: [[@LINE]]:35 -> [[@LINE+15]]:2 : 0
+func f2(_ x : Algebraic) -> Int32 { // CHECK-NEXT: [[@LINE]]:35 -> [[@LINE+16]]:2 : 0
   switch(x) {                       // CHECK-NEXT: [[@LINE]]:9 -> [[@LINE]]:12 : 0
   case let .Type1(y, z):            // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE+1]]:10 : 1
     nop()
   case .Type2(let b):               // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE+2]]:16 : 2
     nop()
     fallthrough
-  case .Type3:                      // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE+3]]:6 : (2 + 3)
+  case .Type3:                      // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE+4]]:7 : (2 + 3)
     if (false) {                    // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE]]:15 : (2 + 3)
       fallthrough                   // CHECK-NEXT: [[@LINE-1]]:16 -> [[@LINE+1]]:6 : 4
-    }                               // CHECK-NEXT: [[@LINE]]:6 -> [[@LINE]]:6 : ((2 + 3) - 4)
+    }                               // CHECK-NEXT: [[@LINE]]:6 -> [[@LINE+1]]:7 : ((2 + 3) - 4)
+    () // Here to make sure this region is non empty ^
   case .Type4:                      // CHECK-NEXT: [[@LINE]]:3 -> [[@LINE+1]]:10 : (4 + 5)
     break
   } // CHECK-NEXT: [[@LINE]]:4 -> [[@LINE+1]]:11 : (((1 + 2) + 3) + 5)
@@ -91,23 +92,25 @@ f2(Algebraic.Type3)
 f3(Simple.Second)
 
 // CHECK-LABEL: sil_coverage_map {{.*}}// coverage_switch.f4
-func f4(_ x: Int) throws -> Int { // CHECK-NEXT: [[@LINE]]:33 -> [[@LINE+21]]:2 : 0
-  y: do {                         // CHECK-NEXT: [[@LINE]]:9 -> [[@LINE+18]]:4 : 0
+func f4(_ x: Int) throws -> Int { // CHECK-NEXT: [[@LINE]]:33 -> [[@LINE+23]]:2 : 0
+  y: do {                         // CHECK-NEXT: [[@LINE]]:9 -> [[@LINE+20]]:4 : 0
     switch x {                    // CHECK-NEXT: [[@LINE]]:12 -> [[@LINE]]:13 : 0
     case 1, 2, 3:                 // CHECK-NEXT: [[@LINE]]:5 -> [[@LINE+4]]:18 : 1
       if .random() {              // CHECK-NEXT: [[@LINE]]:10 -> [[@LINE]]:19 : 1
         return 5                  // CHECK-NEXT: [[@LINE-1]]:20 -> [[@LINE+1]]:8 : 2
       }                           // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE+1]]:18 : (1 - 2)
       fallthrough
-    case 4:                       // CHECK-NEXT: [[@LINE]]:5 -> [[@LINE+4]]:8 : ((1 + 3) - 2)
+    case 4:                       // CHECK-NEXT: [[@LINE]]:5 -> [[@LINE+5]]:9 : ((1 + 3) - 2)
       if .random() {              // CHECK-NEXT: [[@LINE]]:10 -> [[@LINE]]:19 : ((1 + 3) - 2)
         struct E : Error {}       // CHECK-NEXT: [[@LINE-1]]:20 -> [[@LINE+2]]:8 : 4
         throw E()
-      }                           // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE]]:8 : (((1 + 3) - 2) - 4)
-    default:                      // CHECK-NEXT: [[@LINE]]:5 -> [[@LINE+3]]:8 : 5
+      }                           // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE+1]]:9 : (((1 + 3) - 2) - 4)
+      () // Here to make sure this region is non empty ^
+    default:                      // CHECK-NEXT: [[@LINE]]:5 -> [[@LINE+4]]:9 : 5
       if .random() {              // CHECK-NEXT: [[@LINE]]:10 -> [[@LINE]]:19 : 5
         break y                   // CHECK-NEXT: [[@LINE-1]]:20 -> [[@LINE+1]]:8 : 6
-      }                           // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE]]:8 : (5 - 6)
+      }                           // CHECK-NEXT: [[@LINE]]:8 -> [[@LINE+1]]:9 : (5 - 6)
+      () // Here to make sure this region is non empty ^
     }
     f1(0)                         // CHECK-NEXT: [[@LINE-1]]:6 -> [[@LINE+1]]:4 : (((((1 + 3) + 5) - 2) - 4) - 6)
   }

test/Profiler/coverage_toplevel.swift

@@ -17,10 +17,9 @@ func f1() {}
 // CHECK-NEXT: [[@LINE+1]]:1 -> [[@LINE+1]]:18 : 1
 var i : Int32 = 0
 
-// CHECK-NEXT: [[@LINE+4]]:1 -> [[@LINE+6]]:2 : 2
-// CHECK-NEXT: [[@LINE+3]]:7 -> [[@LINE+3]]:15 : (2 + 3)
-// CHECK-NEXT: [[@LINE+2]]:16 -> [[@LINE+4]]:2 : 3
-// CHECK-NEXT: [[@LINE+3]]:2 -> [[@LINE+3]]:2 : 2
+// CHECK-NEXT: [[@LINE+3]]:1 -> [[@LINE+5]]:2 : 2
+// CHECK-NEXT: [[@LINE+2]]:7 -> [[@LINE+2]]:15 : (2 + 3)
+// CHECK-NEXT: [[@LINE+1]]:16 -> [[@LINE+3]]:2 : 3
 while (i < 10) {
   i += 1
 }
@@ -30,10 +29,9 @@ while (i < 10) {
 // CHECK-NEXT: [[@LINE+1]]:21 -> [[@LINE+1]]:22 : (4 - 5)
 var i2 = true ? 1 : 0;
 
-// CHECK-NEXT: [[@LINE+4]]:1 -> [[@LINE+6]]:2 : 6
-// CHECK-NEXT: [[@LINE+3]]:4 -> [[@LINE+3]]:10 : 6
-// CHECK-NEXT: [[@LINE+2]]:11 -> [[@LINE+4]]:2 : 7
-// CHECK-NEXT: [[@LINE+3]]:2 -> [[@LINE+3]]:2 : 6
+// CHECK-NEXT: [[@LINE+3]]:1 -> [[@LINE+5]]:2 : 6
+// CHECK-NEXT: [[@LINE+2]]:4 -> [[@LINE+2]]:10 : 6
+// CHECK-NEXT: [[@LINE+1]]:11 -> [[@LINE+3]]:2 : 7
 if (true) {
   i2 = 2
 }

test/Profiler/coverage_while.swift

@@ -123,6 +123,10 @@ func goo() {
   } while false // CHECK-DAG: [[@LINE]]:11 -> [[@LINE]]:16 : ([[RWS8]] - [[RET1]])
 }
 
-eoo()
-foo()
-goo()
+// CHECK-LABEL: sil_coverage_map {{.*}}// coverage_while.hoo
+func hoo() {       // CHECK-NEXT: [[@LINE]]:12 -> [[@LINE+5]]:2 : 0
+  var i: Int = 0
+  while (i < 10) { // CHECK-NEXT: [[@LINE]]:9 -> [[@LINE]]:17 : (0 + 1)
+    i += 1         // CHECK-NEXT: [[@LINE-1]]:18 -> [[@LINE+1]]:4 : 1
+  }                // CHECK-NEXT: [[@LINE]]:4 -> [[@LINE+1]]:2 : 0
+}