ci: Use -fsanitize=undefined,alignment,address in linux tasks

We have coverage of the various sanitizers in the buildfarm. The sanitizers
however particularly interesting during the development of patches, where the
likelihood of bugs is even higher. There also have been complaints about only
seeing such failures on the buildfarm, rather than before commit.

This commit enables a reasonable set of sanitizers in CI. Use the linux task
for that, as it currently is one of the fastests tasks. Also several of the
sanitizers work best on linux.

The overhead of alignment sanitizer is low, undefined behaviour has moderate
overhead. Test alignment sanitizer in the meson task, as it does both 32 and
64 bit builds and is thus more likely to expose alignment bugs.

Address sanitizer in contrast somewhat expensive. Enable it in the autoconf
task, as the meson task tests both 32 and 64bit which would exacerbate the
cost.

Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20220323173537.ll7klrglnp4gn2um@alap3.anarazel.de
Discussion: https://postgr.es/m/20221121220903.kf5u7rokfzbmqskm@alap3.anarazel.de

.cirrus.yml

@@ -235,8 +235,28 @@ task:
     CCACHE_DIR: /tmp/ccache_dir
     DEBUGINFOD_URLS: "https://debuginfod.debian.net"
 
-    CFLAGS: -Og -ggdb
-    CXXFLAGS: -Og -ggdb
+    # Enable a reasonable set of sanitizers. Use the linux task for that, as
+    # it one of the fastest tasks (without sanitizers). Also several of the
+    # sanitizers work best on linux.
+    #
+    # The overhead of alignment sanitizer is low, undefined behaviour has
+    # moderate overhead. Test alignment sanitizer in the meson task, as it
+    # does both 32 and 64 bit builds and is thus more likely to expose
+    # alignment bugs.
+    #
+    # Address sanitizer in contrast is somewhat expensive. Enable it in the
+    # autoconf task, as the meson task tests both 32 and 64bit.
+    #
+    # disable_coredump=0, abort_on_error=1: for useful backtraces in case of crashes
+    # print_stacktraces=1,verbosity=2, duh
+    # detect_leaks=0: too many uninteresting leak errors in short-lived binaries
+    UBSAN_OPTIONS: print_stacktrace=1:disable_coredump=0:abort_on_error=1:verbosity=2
+    ASAN_OPTIONS: print_stacktrace=1:disable_coredump=0:abort_on_error=1:detect_leaks=0
+
+    # SANITIZER_FLAGS is set in the tasks below
+    CFLAGS: -Og -ggdb -fno-sanitize-recover=all $SANITIZER_FLAGS
+    CXXFLAGS: $CFLAGS
+    LDFLAGS: $SANITIZER_FLAGS
     CC: ccache gcc
     CXX: ccache g++
 
@@ -280,6 +300,9 @@ task:
   matrix:
     - name: Linux - Debian Bullseye - Autoconf
 
+      env:
+        SANITIZER_FLAGS: -fsanitize=address
+
       configure_script: |
         su postgres <<-EOF
           ./configure \
@@ -306,6 +329,7 @@ task:
 
       env:
         CCACHE_MAXSIZE: "400M" # tests two different builds
+        SANITIZER_FLAGS: -fsanitize=alignment,undefined
 
       configure_script: |
         su postgres <<-EOF