IMPALA-11110: Switch debug builds to use -Og

GCC's -Og applies optimizations that are compatible with
being debuggable. It is similar to -O1 and results
in a modest speed-up. This modifies the default debug
build to use -Og, so it is now more akin to a fastdebug
mode.

Even though -Og is intended to preserve debuggability,
optimization always impacts debuggability and -Og is
no exception. To enable the old behavior, this adds
a DEBUG_NOOPT build mode that retains the old
non-optimized behavior. Using the -debug_noopt flag
with buildall.sh enables this behavior.

Change-Id: Ie06c149c8181c90572b8668bd01dfd26c0a5971e
Reviewed-on: http://gerrit.cloudera.org:8080/18200
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Reviewed-by: Laszlo Gaal (Cloudera) <laszlo.gaal@cloudera.com>
Reviewed-by: Csaba Ringhofer <csringhofer@cloudera.com>

buildall.sh

@@ -75,6 +75,7 @@ BUILD_UBSAN=0
 BUILD_UBSAN_FULL=0
 BUILD_TSAN=0
 BUILD_TSAN_FULL=0
+BUILD_DEBUG_NOOPT=0
 BUILD_SHARED_LIBS=0
 # Export MAKE_CMD so it is visible in scripts that invoke make, e.g. copy-udfs-udas.sh
 export MAKE_CMD=make
@@ -145,9 +146,12 @@ do
     -tsan)
       BUILD_TSAN=1
       ;;
-     -full_tsan)
+    -full_tsan)
       BUILD_TSAN_FULL=1
       ;;
+    -debug_noopt)
+      BUILD_DEBUG_NOOPT=1
+      ;;
     -testpairwise)
       EXPLORATION_STRATEGY=pairwise
       ;;
@@ -226,6 +230,10 @@ do
       echo "[-full_ubsan] : Undefined behavior sanitizer build, including code generated"\
            "by cross-compilation to LLVM IR. Much slower queries than plain -ubsan"\
            "[Default: False]"
+      echo "[-debug_noopt] : Debug build without optimizations applied. The regular"\
+           "debug build applies basic optimizations, but even these optimizations may"\
+           "impact debuggability, so this is an option to omit the optimizations."\
+           "[Default: False]"
       echo "[-skiptests] : Skips execution of all tests"
       echo "[-notests] : Skips building and execution of all tests"
       echo "[-start_minicluster] : Start test cluster including Impala and all"\
@@ -325,6 +333,10 @@ if [[ ${BUILD_TSAN_FULL} -eq 1 ]]; then
   CMAKE_BUILD_TYPE_LIST+=(TSAN_FULL)
   export TSAN_FULL=1
 fi
+if [[ ${BUILD_DEBUG_NOOPT} -eq 1 ]]; then
+  CMAKE_BUILD_TYPE_LIST+=(DEBUG_NOOPT)
+  export DEBUG_NOOPT=1
+fi
 if [[ -n "${CMAKE_BUILD_TYPE_LIST:+1}" ]]; then
   if [[ ${#CMAKE_BUILD_TYPE_LIST[@]} -gt 1 ]]; then
     echo "ERROR: more than one CMake build type defined: ${CMAKE_BUILD_TYPE_LIST[@]}"