llvm-cov: add test for function & file association in the reports.

[arphaman]

Summary

The attached patch contains a test which checks that the functions defined in header files will get associated with header files rather than source files for the reports.
This is a standalone test patch without any functionality change, because I've originally intended to create a patch which changes the association (so that the header defined functions will be associated with the non-header files), but now I think that the default approach is better.

[arphaman]

Closed by commit rL218673 (authored by @arphaman).

llvm/trunk/test/tools/llvm-cov/Inputs/reportFunctionPlacement.h

+
+void foo(int x) {
+  int y = x + 1;
+}
+
+void bar() {
+
+}

llvm/trunk/test/tools/llvm-cov/reportFunctionPlacement.cpp

+// RUN: llvm-cov report %S/Inputs/reportFunctionPlacement.covmapping -instr-profile %S/Inputs/reportFunctionPlacement.profdata -no-colors 2>&1 | FileCheck %s
+// This test checks that the functions defined in header files will get
+// associated with header files rather than source files for the reports.
+
+#include "Inputs/reportFunctionPlacement.h"
+
+// CHECK: Filename                    Regions    Miss   Cover Functions  Executed
+// CHECK: ---
+// CHECK: ...ortFunctionPlacement.h         2       1  50.00%         2    50.00%
+// CHECK: ...tFunctionPlacement.cpp         2       0 100.00%         2   100.00%
+// CHECK: ---
+// CHECK: TOTAL                             4       1  75.00%         4    75.00%
+
+void func() {
+}
+
+int main() {
+  foo(10);
+  func();
+  return 0;
+}
+
+// llvm-cov doesn't work on big endian yet
+// XFAIL: powerpc64-, s390x, mips-, mips64-, sparc