[coverage] Special-case calls to noreturn functions.

The code after a noreturn call doesn't execute.

The pattern in the testcase is pretty common in LLVM (a switch with
a default case that calls llvm_unreachable).

The original version of this patch was reverted in r309995 due to a
crash. This version includes a fix for that crash (testcase in 
test/CoverageMapping/md.cpp).

Differential Revision: https://reviews.llvm.org/D36250

llvm-svn: 310406

1 files changed, 11 insertions, 0 deletions

diff --git a/clang/test/CoverageMapping/md.cpp b/clang/test/CoverageMapping/md.cpp
index 20c696c7dfb..5f2b2d61224 100644
--- a/clang/test/CoverageMapping/md.cpp
+++ b/clang/test/CoverageMapping/md.cpp
@@ -27,6 +27,17 @@ void foo(MD i) {
   #include "Inputs/md.def"
 }
 
+// CHECK: bar
+// CHECK-NEXT: File 0, [[@LINE+3]]:12 -> [[@LINE+8]]:2 = #0
+bool isVal1();
+bool isVal2();
+bool bar() {
+ #define HANDLE_MD(X) is##X() ||
+  return
+#include "Inputs/md.def"
+  0;
+}
+
 int main(int argc, const char *argv[]) {
   foo(MD::Val1);
   return 0;