Add a test to validate libclang's ABI compatibility on Fedora

This test uses abi-compliance-checker in order to compare the ABI of the
current libclang.so with previous versions that are stored in a separate
git-lfs repository.

This new test may take as long as 20 minutes to complete and consumes
far more RAM than previous tests (up to 8 GiB).

abi/main.fmf

@@ -0,0 +1,22 @@
+summary: Test ABI compatibility.
+test: ./test.sh
+framework: shell
+tier: 1
+component:
+  - llvm-toolset
+  - clang
+require:
+  - abi-compliance-checker
+  - binutils
+  - gzip
+  - clang-devel
+  - clang-libs
+  - clang-libs-debuginfo
+  - wget
+  - xz
+duration: 40m
+
+adjust:
+  # TODO: Test on rhel before enabling it
+  - enabled: false
+    when: distro == rhel or distro == centos

abi/test.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/sh -ex
+
+# Test the compatibility of the current libclang with specific versions that
+# have been previously generated.
+# The artifacts used as input in this test are maintained in this git-lfs
+# repo: https://gitlab.com/tuliom-rh/llvm-fedora-el-abi
+
+is_fedora=`rpm -E %{fedora}`
+arch=`rpm -E %{_arch}`
+
+case $(rpm -E %dist) in
+    .fc*) dist_prefix=fc;;
+    .el*) dist_prefix=el;;
+    *) echo "Error: which distro is this ($(rpm -E %dist))?" >&2
+esac
+
+# Download ABI dumps from previous versions.
+wget -q https://gitlab.com/tuliom-rh/llvm-fedora-el-abi/-/archive/main/llvm-fedora-el-abi-main.tar.gz
+tar xzf llvm-fedora-el-abi-main.tar.gz --strip-components=1 '*/libclang.*.abi.xz'
+
+for f in *.abi.xz; do
+    unxz $f
+done
+
+abi_files=$(ls libclang*.$dist_prefix*.$arch.abi)
+
+abi_file=libclang.$(rpm -q clang-libs | sed 's/~//g').abi
+version=$(rpm -q --qf "%{V}-%{R}.%{ARCH}\n" clang-libs)
+library=$(rpm -ql clang-libs | grep -E 'libclang\.so\..*' | sort | head -n 1)
+debuginfo=$(rpm -ql clang-libs-debuginfo | grep -E 'libclang\.so.*\.debug')
+
+# Create the ABI dump from the current version. This takes a long time.
+abi-dumper -quiet -lver $version \
+    -skip-cxx \
+    -public-headers /usr/include/clang-c \
+    --search-debuginfo=/usr/lib/debug \
+    -o $abi_file $library
+
+sed -i 's/LLVM_[0-9]\+/LLVM_NOVERSION/' $abi_file
+
+for old_abi_file in $abi_files; do
+    abi-compliance-checker -l libclang.so -old $old_abi_file -new $abi_file
+done

build-gating.fmf

@@ -64,4 +64,4 @@ execute:
     how: tmt
 provision:
   hardware:
-    memory: ">= 4 GiB"
+    memory: ">= 8 GiB"