ARROW-3972: misc fixes for LLVM7

ci/travis_env_common.sh

@@ -23,7 +23,7 @@ export MINICONDA=$HOME/miniconda
 export CONDA_PKGS_DIRS=$HOME/.conda_packages
 export CONDA_BINUTILS_VERSION=2.31
 
-export ARROW_LLVM_VERSION=7
+export ARROW_LLVM_VERSION=7.0
 export CONDA_LLVM_VERSION="7.0.*"
 
 export ARROW_CPP_DIR=$TRAVIS_BUILD_DIR/cpp

ci/travis_install_clang_tools.sh

@@ -22,8 +22,11 @@ set -ex
 
 source $TRAVIS_BUILD_DIR/ci/travis_env_common.sh
 
+# extract the major version
+ARROW_LLVM_MAJOR_VERSION=$(echo $ARROW_LLVM_VERSION | cut -d. -f1)
+
 wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key|sudo apt-key add -
 sudo apt-add-repository -y \
-     "deb https://llvm.org/apt/$DISTRO_CODENAME/ llvm-toolchain-$DISTRO_CODENAME-$ARROW_LLVM_VERSION main"
+     "deb https://apt.llvm.org/$DISTRO_CODENAME/ llvm-toolchain-$DISTRO_CODENAME-$ARROW_LLVM_MAJOR_VERSION main"
 sudo apt-get update -qq
-sudo apt-get install -q clang-$ARROW_LLVM_VERSION clang-format-$ARROW_LLVM_VERSION clang-tidy-$ARROW_LLVM_VERSION
+sudo apt-get install -q clang-$ARROW_LLVM_MAJOR_VERSION clang-format-$ARROW_LLVM_MAJOR_VERSION clang-tidy-$ARROW_LLVM_MAJOR_VERSION

ci/travis_install_linux.sh

@@ -37,16 +37,13 @@ if [ "$ARROW_TRAVIS_COVERAGE" == "1" ]; then
     sudo apt-get install -y -qq lcov
 fi
 
+set -x
 if [ "$ARROW_TRAVIS_GANDIVA" == "1" ]; then
     sudo apt-get install -y -qq llvm-$ARROW_LLVM_VERSION-dev
 fi
 
 set -x
 if [ "$DISTRO_CODENAME" != "trusty" ]; then
-    if [ "$ARROW_TRAVIS_GANDIVA" == "1" ]; then
-        sudo apt-get install -y -qq llvm-$ARROW_LLVM_VERSION-dev
-    fi
-
     sudo apt-get install -y -qq maven
 
     # Remove Travis-specific versions of Java

cpp/README.md

@@ -300,7 +300,7 @@ sudo apt-get install llvm-7.0-dev
 On macOS, you can use [Homebrew][1]:
 
 ```shell
-brew install llvm@6
+brew install llvm@7
 ```
 
 The optional `gandiva` libraries and tests can be built by passing

cpp/cmake_modules/FindLLVM.cmake

@@ -25,7 +25,7 @@ if (APPLE)
   find_program(BREW_BIN brew)
   if (BREW_BIN)
     execute_process(
-      COMMAND ${BREW_BIN} --prefix "llvm@6"
+      COMMAND ${BREW_BIN} --prefix "llvm@7"
       OUTPUT_VARIABLE LLVM_BREW_PREFIX
       OUTPUT_STRIP_TRAILING_WHITESPACE
     )
@@ -43,16 +43,6 @@ message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")
 # Find the libraries that correspond to the LLVM components
 llvm_map_components_to_libnames(LLVM_LIBS core mcjit native ipo bitreader target linker analysis debuginfodwarf)
 
-find_program(CLANG_EXECUTABLE
-  NAMES clang-${ARROW_LLVM_VERSION}
-  clang-${ARROW_LLVM_MAJOR_VERSION}
-  HINTS ${LLVM_TOOLS_BINARY_DIR})
-if (CLANG_EXECUTABLE)
-  message(STATUS "Found clang ${CLANG_EXECUTABLE}")
-else ()
-  message(FATAL_ERROR "Couldn't find clang")
-endif ()
-
 find_program(LLVM_LINK_EXECUTABLE llvm-link
   HINTS ${LLVM_TOOLS_BINARY_DIR})
 if (LLVM_LINK_EXECUTABLE)
@@ -61,6 +51,24 @@ else ()
   message(FATAL_ERROR "Couldn't find llvm-link")
 endif ()
 
+find_program(CLANG_EXECUTABLE
+  NAMES clang-${ARROW_LLVM_VERSION}
+  clang-${ARROW_LLVM_MAJOR_VERSION}
+  HINTS ${LLVM_TOOLS_BINARY_DIR})
+if (CLANG_EXECUTABLE)
+  message(STATUS "Found clang ${ARROW_LLVM_VERSION} ${CLANG_EXECUTABLE}")
+else ()
+  # If clang-7 not available, switch to normal clang.
+  find_program(CLANG_EXECUTABLE
+    NAMES clang
+    HINTS ${LLVM_TOOLS_BINARY_DIR})
+  if (CLANG_EXECUTABLE)
+    message(STATUS "Found clang ${CLANG_EXECUTABLE}")
+  else ()
+    message(FATAL_ERROR "Couldn't find clang")
+  endif ()
+endif ()
+
 add_library(LLVM::LLVM_INTERFACE INTERFACE IMPORTED)
 
 set_target_properties(LLVM::LLVM_INTERFACE PROPERTIES

dev/tasks/gandiva-jars/travis.linux.yml

@@ -50,8 +50,8 @@ before_script:
 
 script:
   - mkdir -p dist
-  - arrow/dev/tasks/gandiva-jars/build-cpp.sh
-  - arrow/dev/tasks/gandiva-jars/build-java.sh
+  - arrow/dev/tasks/gandiva-jars/build-cpp.sh || travis_terminate 1
+  - arrow/dev/tasks/gandiva-jars/build-java.sh || travis_terminate 1
 
 deploy:
   provider: releases

dev/tasks/gandiva-jars/travis.osx.yml

@@ -40,8 +40,8 @@ before_script:
 
 script:
   - mkdir -p dist
-  - arrow/dev/tasks/gandiva-jars/build-cpp.sh
-  - arrow/dev/tasks/gandiva-jars/build-java.sh
+  - arrow/dev/tasks/gandiva-jars/build-cpp.sh || travis_terminate 1
+  - arrow/dev/tasks/gandiva-jars/build-java.sh || travis_terminate 1
 
 deploy:
   provider: releases