ARROW-3440: [Gandiva] fix typos and address review

- label all gandiva tests with gandiva

ci/travis_script_gandiva_cpp.sh

@@ -23,10 +23,10 @@ source $TRAVIS_BUILD_DIR/ci/travis_env_common.sh
 
 pushd $CPP_BUILD_DIR
 
-PATH=$ARROW_BUILD_TYPE:$PATH ctest -j2 --output-on-failure -L unittest
+PATH=$ARROW_BUILD_TYPE:$PATH ctest -j2 --output-on-failure -L gandiva,unittest
 
 # not running in parallel, since some of them are benchmarks
-PATH=$ARROW_BUILD_TYPE:$PATH ctest -VV -L integ
+PATH=$ARROW_BUILD_TYPE:$PATH ctest -VV -L gandiva,integ
 
 popd
 

cpp/README.md

@@ -227,13 +227,18 @@ still in Alpha stages, and subject to API changes without deprecation warnings.
 
 ### Building and developing Gandiva (optional)
 
-In addition to the arrow dependancies, gandiva requires :
+The Gandiva library supports compiling and evaluating expressions on arrow
+data. It uses LLVM for doing just-in-time compilation of the expressions.
+
+In addition to the arrow dependencies, gandiva requires :
 * On linux, gcc 4.9 or higher C++11-enabled compiler.
 * LLVM
 
 On Ubuntu/Debian you can install these requirements with:
 
 ```shell
+sudo apt-add-repository -y "deb http://llvm.org/apt/trusty/ llvm-toolchain-trusty-6.0 main"
+sudo apt-get update -qq
 sudo apt-get install llvm-6.0-dev
 ```
 
@@ -249,8 +254,7 @@ The optional `gandiva` libraries and tests can be built by passing
 ```shell
 cmake .. -DARROW_GANDIVA=on
 make
-ctest -L unitest
-ctest -L integ
+ctest -L gandiva
 ```
 
 This library is still in Alpha stages, and subject to API changes without

cpp/cmake_modules/GandivaBuildUtils.cmake

@@ -94,7 +94,7 @@ function(add_gandiva_unit_test REL_TEST_NAME)
     PRIVATE arrow_shared ${GANDIVA_TEST_LINK_LIBS} Boost::boost
   )
   add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME})
-  set_property(TEST ${TEST_NAME} PROPERTY LABELS unittest ${TEST_NAME})
+  set_property(TEST ${TEST_NAME} PROPERTY LABELS gandiva,unittest ${TEST_NAME})
 endfunction(add_gandiva_unit_test REL_TEST_NAME)
 
 # Add a unittest executable for a precompiled file (used to generate IR)
@@ -109,7 +109,7 @@ function(add_precompiled_unit_test REL_TEST_NAME)
   target_compile_definitions(${TEST_NAME} PRIVATE GANDIVA_UNIT_TEST=1)
   target_compile_definitions(${TEST_NAME} PRIVATE -DGDV_HELPERS)
   add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME})
-  set_property(TEST ${TEST_NAME} PROPERTY LABELS unittest ${TEST_NAME})
+  set_property(TEST ${TEST_NAME} PROPERTY LABELS gandiva,unittest ${TEST_NAME})
 endfunction(add_precompiled_unit_test REL_TEST_NAME)
 
 # Add an integ executable, with its dependencies.
@@ -121,7 +121,7 @@ function(add_gandiva_integ_test REL_TEST_NAME GANDIVA_LIB)
   target_link_libraries(${TEST_NAME}_${GANDIVA_LIB} PRIVATE ${GANDIVA_LIB} ${GANDIVA_TEST_LINK_LIBS})
 
   add_test(NAME ${TEST_NAME}_${GANDIVA_LIB} COMMAND ${TEST_NAME}_${GANDIVA_LIB})
-  set_property(TEST ${TEST_NAME}_${GANDIVA_LIB} PROPERTY LABELS integ ${TEST_NAME}_${GANDIVA_LIB})
+  set_property(TEST ${TEST_NAME}_${GANDIVA_LIB} PROPERTY LABELS gandiva,integ ${TEST_NAME}_${GANDIVA_LIB})
 endfunction(add_gandiva_integ_test REL_TEST_NAME)
 
 function(prevent_in_source_builds)

cpp/src/gandiva/jni/CMakeLists.txt

@@ -17,8 +17,6 @@
 
 project(gandiva_jni)
 
-set(Protobuf_USE_STATIC_LIBS "ON")
-
 # Find JNI
 find_package(JNI REQUIRED)