InstrProf: Make sure counts in lambdas don't escape to the parent scope

When generating coverage maps, we were traversing the body as if it
were part of the parent function, but this doesn't make sense since
we're currently counting lambdas as separate functions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@230304 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CoverageMappingGen.cpp

@@ -850,6 +850,11 @@ struct CounterCoverageMappingBuilder
     extendRegion(E->getRHS());
     propagateCounts(getRegionCounter(E), E->getRHS());
   }
+
+  void VisitLambdaExpr(const LambdaExpr *LE) {
+    // Lambdas are treated as their own functions for now, so we shouldn't
+    // propagate counts into them.
+  }
 };
 }
 

test/CoverageMapping/lambda.cpp

@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -x c++ -std=c++11 -triple %itanium_abi_triple -fprofile-instr-generate -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only %s -main-file-name lambda.cpp | FileCheck %s
+
+// CHECK-LABEL: _Z3fooi:
+void foo(int i) { // CHECK: File 0, [[@LINE]]:17 -> {{[0-9]+}}:2 = #0
+  auto f = [](int x) {
+    return x + 1;
+  };
+
+  f(i);
+  // Make sure the zero region after the return doesn't escape the lambda.
+  // CHECK-NOT: File 0, {{[0-9:]+}} -> [[@LINE+1]]:2 = 0
+}
+
+int main(int argc, const char *argv[]) {
+  foo(1);
+  return 0;
+}