travis: Add code coverage on success

Update the code coverage of the project on codecov for easy viewing.

Also the gcov on travis uses a different version which cannot
find the directory of the given files, and it needs to be specified
in the -o flag. Hence now we loop over the list of files and
run them independently.

.travis.yml

@@ -70,6 +70,10 @@ before_cache:
 after_failure:
   - tests/travis/travis_after_failure.sh
 
+after_success:
+  - tree build
+  - bash <(curl -s https://codecov.io/bash) -a '-o src/ src/*.c'
+
 notifications:
   email:
     on_success: change

Makefile

@@ -160,7 +160,9 @@ check: test
 
 ifeq ($(TEST_COVER), 1)
 cover: check
-	gcov -pbcu $(COVER_OBJ)
+	@- $(foreach COV_OBJ, $(COVER_OBJ), \
+		gcov -pbcul -o $(shell dirname $(COV_OBJ)) $(COV_OBJ) > gcov.log || cat gcov.log; \
+	)
 endif
 
 clean:

tests/travis/run_test.sh

@@ -94,5 +94,5 @@ if [ ${TASK} == "cpp_test" ]; then
     make -f dmlc-core/scripts/packages.mk gtest
     echo "TEST_COVER=1" >> config.mk
     echo "GTEST_PATH="${CACHE_PREFIX} >> config.mk
-    make check
+    make cover
 fi