[#2979] Allow controlling ccache directory location with an environme…

…nt variable

Summary:
Allow controlling ccache directory location with an environment variable. Before this change, we are using the default ~/.ccache directory, except on Jenkins.

Also remove the `--gen-compilation-db` flag from `yb_build.sh` as it has been superseded by the `compilecmds` build type.

Test Plan:
Jenkins: compile only

`export YB_CCACHE_DIR=/some/directory; ./yb_build.sh`

Reviewers: jason, timur

Reviewed By: timur

Subscribers: ybase

Differential Revision: https://phabricator.dev.yugabyte.com/D7595

build-support/common-build-env.sh

@@ -179,6 +179,8 @@ declare -i -r YB_DOWNLOAD_LOCK_TIMEOUT_SEC=120
 
 readonly YB_DOWNLOAD_LOCKS_DIR=/tmp/yb_download_locks
 
+readonly YB_NFS_PATH_RE="^/(n|z|u|net|Volumes/net)/"
+
 # -------------------------------------------------------------------------------------------------
 # Functions
 # -------------------------------------------------------------------------------------------------
@@ -1419,7 +1421,7 @@ is_jenkins_phabricator_build() {
 
 # Check if we're using an NFS partition in YugaByte's build environment.
 is_src_root_on_nfs() {
-  if [[ $YB_SRC_ROOT =~ ^/(n|z|u|net|Volumes/net)/ ]]; then
+  if [[ $YB_SRC_ROOT =~ $YB_NFS_PATH_RE ]]; then
     return 0
   fi
   return 1

build-support/compiler-wrappers/compiler-wrapper.sh

@@ -604,22 +604,28 @@ if which ccache >/dev/null && ! "$compiling_pch" && [[ -z ${YB_NO_CCACHE:-} ]];
   export CCACHE_CC="$compiler_executable"
   export CCACHE_SLOPPINESS="file_macro,pch_defines,time_macros"
   export CCACHE_BASEDIR=$YB_SRC_ROOT
-  if is_jenkins; then
-    # Enable reusing cache entries from builds in different directories, potentially with incorrect
-    # file paths in debug information. This is OK for Jenkins because we probably won't be running
-    # these builds in the debugger.
-    export CCACHE_NOHASHDIR=1
-  fi
+
   # Ensure CCACHE puts temporary files on the local disk.
   export CCACHE_TEMPDIR=${CCACHE_TEMPDIR:-/tmp/ccache_tmp_$USER}
-  jenkins_ccache_dir=/n/jenkins/ccache
-  if [[ $USER == "jenkins" && -d $jenkins_ccache_dir ]] && is_src_root_on_nfs; then
-    if [[ ${YB_DEBUG_CCACHE:-0} == "1" ]] && ! is_jenkins; then
-      log "is_jenkins (based on JOB_NAME) is false for some reason, even though" \
-          "the user is 'jenkins'. Setting CCACHE_DIR to '$jenkins_ccache_dir' anyway." \
-          "This is host $HOSTNAME, and current directory is $PWD."
+  if [[ -n ${YB_CCACHE_DIR:-} ]]; then
+    export CCACHE_DIR=$YB_CCACHE_DIR
+  else
+    jenkins_ccache_dir=/n/jenkins/ccache
+    if [[ $USER == "jenkins" && -d $jenkins_ccache_dir ]] && is_src_root_on_nfs; then
+      # Enable reusing cache entries from builds in different directories, potentially with
+      # incorrect file paths in debug information. This is OK for Jenkins because we probably won't
+      # be running these builds in the debugger.
+      export CCACHE_NOHASHDIR=1
+
+      if [[ ${YB_DEBUG_CCACHE:-0} == "1" ]] && ! is_jenkins; then
+        log "is_jenkins (based on JOB_NAME) is false for some reason, even though" \
+            "the user is 'jenkins'. Setting CCACHE_DIR to '$jenkins_ccache_dir' anyway." \
+            "This is host $HOSTNAME, and current directory is $PWD."
+      fi
+      export CCACHE_DIR=$jenkins_ccache_dir
     fi
-    export CCACHE_DIR=$jenkins_ccache_dir
+  fi
+  if [[ ${CCACHE_DIR:-} =~ $YB_NFS_PATH_RE ]]; then
     # Do not update the stats file, because that involves locking and might be problematic/slow
     # on NFS.
     export CCACHE_NOSTATS=1

yb_build.sh

@@ -591,7 +591,6 @@ java_test_name=""
 show_report=true
 running_any_tests=false
 clean_postgres=false
-export_compile_commands=false
 make_ninja_extra_args=""
 java_lint=false
 
@@ -918,9 +917,6 @@ while [[ $# -gt 0 ]]; do
     --no-postgres|--skip-postgres|--np|--sp)
       export YB_SKIP_POSTGRES_BUILD=1
     ;;
-    --gen-compilation-db|--gcdb)
-      export_compile_commands=true
-    ;;
     --run-java-test-methods-separately|--rjtms)
       export YB_RUN_JAVA_TEST_METHODS_SEPARATELY=1
     ;;
@@ -1056,16 +1052,6 @@ if "$use_nfs_shared_thirdparty" && "$no_shared_thirdparty"; then
   fatal "--use-shared-thirdparty and --no-shared-thirdparty cannot be specified at the same time"
 fi
 
-if "$export_compile_commands" && ! "$force_no_run_cmake"; then
-  force_run_cmake=true
-fi
-
-if "$export_compile_commands"; then
-  log "Will export compile commands (create a compilation database JSON file)"
-  export CMAKE_EXPORT_COMPILE_COMMANDS=1
-  export YB_EXPORT_COMPILE_COMMANDS=1
-fi
-
 configure_remote_compilation
 do_not_use_local_thirdparty_flag_path=$YB_SRC_ROOT/thirdparty/.yb_thirdparty_do_not_use
 
@@ -1086,6 +1072,13 @@ if "$java_lint"; then
   lint_java_code
   exit
 fi
+
+if ! is_jenkins && is_src_root_on_nfs && \
+  [[ -z ${YB_CCACHE_DIR:-} && $HOME =~ $YB_NFS_PATH_RE ]]; then
+  export YB_CCACHE_DIR=$HOME/.ccache
+  log "Setting YB_CCACHE_DIR=$YB_CCACHE_DIR by default for NFS-based builds"
+fi
+
 # -------------------------------------------------------------------------------------------------
 # Recursively invoke this script in order to save the log to a file.
 # -------------------------------------------------------------------------------------------------