make-compilation-db: trigger relevant dependency fetches in script.

Move the burden to make sure all dependencies are prefetched
from the caller of make-compilation-db.sh to the script itself.

.github/bin/make-compilation-db.sh

@@ -16,19 +16,38 @@
 set -u
 set -e
 
-BANT=${BANT:-bant}
+# Which bazel and bant to use can be chosen by environment variables
+BAZEL=${BAZEL:-bazel}
+BANT=${BANT:-needs-to-be-compiled-locally}
 
-if [ ! -e bazel-bin ]; then
-  echo "Before creating compilation DB, run bazel build first to fetch deps."
-  exit 1
+BAZEL_OPTS="-c opt --noshow_progress"
+if [ "${BANT}" = "needs-to-be-compiled-locally" ]; then
+  # Bant not given, compile from bzlmod dep. We need to do that before
+  # we run other bazel rules below as we change the cxxopt flags. Remember
+  # the full realpath of the resulting binary to be immune to symbolic-link
+  # switcharoo by bazel.
+  ${BAZEL} build ${BAZEL_OPTS} --cxxopt=-std=c++20 @bant//bant:bant
+  BANT=$(realpath bazel-bin/external/bant*/bant/bant)
 fi
 
-bazel run --cxxopt=-std=c++20 @bant//bant:bant -- \
-      -C $(pwd) compile-flags 2>/dev/null > compile_flags.txt
+# Bazel-build all targets that generate files, so that they can be
+# seen in dependency analysis.
+${BAZEL} build ${BAZEL_OPTS} $(${BANT} list-targets | \
+  egrep "genrule|cc_proto_library|genlex|genyacc" | awk '{print $3}')
 
-# Bant does not see yet the flex dependency inside the toolchain
+# Some selected targets to trigger all dependency fetches from MODULE.bazel
+# verilog-y-final to create a header, kzip creator to trigger build of any.pb.h
+# and some test that triggers fetching nlohmann_json and gtest
+${BAZEL} build ${BAZEL_OPTS} //verible/verilog/parser:verilog-y-final \
+  //verible/verilog/tools/kythe:verible-verilog-kythe-kzip-writer \
+  //verible/common/lsp:json-rpc-dispatcher_test
+
+# bant does not distinguish the includes per file yet, so instead of
+# a compile_commands.json, we can just as well create a simpler
+# compile_flags.txt which is easier to digest for all kinds of tools anyway.
+${BANT} compile-flags 2>/dev/null > compile_flags.txt
+
+# Bant does not see the flex dependency inside the toolchain yet.
 for d in bazel-out/../../../external/*flex*/src/FlexLexer.h ; do
   echo "-I$(dirname $d)" >> compile_flags.txt
 done
-
-echo "Now, re-run original build to make all artifacts visible to clang-tidy"

.github/workflows/verible-ci.yml

@@ -72,11 +72,11 @@ jobs:
         apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 15CF4D18AF4F7421
         wget https://apt.llvm.org/llvm.sh
         chmod +x ./llvm.sh
-        ./llvm.sh 17
+        ./llvm.sh 18
 
     - name: Install other Dependencies
       run: |
-        apt -qq -y install clang-tidy-11 clang-tidy-17 build-essential git wget
+        apt -qq -y install clang-tidy-11 clang-tidy-18 build-essential git wget
         source ./.github/settings.sh
         ./.github/bin/install-bazel.sh
 
@@ -97,24 +97,17 @@ jobs:
 
     - name: Run clang tidy
       run: |
-        echo "::group::Trigger fetch and preparation"
-        bazel build -c opt :install-binaries
-        echo "::endgroup::"
-
         echo "::group::Make Compilation DB"
         .github/bin/make-compilation-db.sh
         cat compile_flags.txt
         echo "::endgroup::"
 
-        echo "::group::Re-etablish links"
-        bazel build -c opt :install-binaries
-        echo "::endgroup::"
-
-        # For runtime references, use clang-tidy 11 that still has it, everything else: latest.
+        # For runtime references, use clang-tidy 11 that still has it,
+        # everything else: latest.
         CLANG_TIDY=clang-tidy-11 ./.github/bin/run-clang-tidy-cached.cc --checks="-*,google-runtime-references" \
            || ( cat verible_clang-tidy.out ; exit 1)
 
-        CLANG_TIDY=clang-tidy-17 ./.github/bin/run-clang-tidy-cached.cc \
+        CLANG_TIDY=clang-tidy-18 ./.github/bin/run-clang-tidy-cached.cc \
             || ( cat verible_clang-tidy.out ; exit 1)
 
     - name: 📤 Upload performance graphs