Enrolled the Cortex-R52 port in the LLVM C check and exposed the skipped examples (#600)

Two gaps in check_clang.sh, both of which made the Cortex-R52 port look better
covered than it was.

C_CORES gains cortex_r52. That list is described as one core per architecture
profile, and Armv8-R AArch32 is a profile rather than a variant of Armv7-R: the
port is written by hand instead of generated from ports_arch, so cortex_r5 does
not stand in for its tx_port.h. The assembly was already covered, since #593
added the PORT_TARGET entry, but the common C sources had never been compiled
against that header.

The example stage skipped any directory lacking both driver scripts, and did so
in silence. A port absent from the count reads as covered, which is how the two
CMake based example builds under ports/cortex_r52 looked like part of the total
while never being built. The stage now reports what it passed over, in the two
distinct cases that exist. The comment above EXAMPLES_EXPECTED_TO_FAIL already
asks for gaps to stay visible; this makes the code agree with it.

Four Cortex-M ports turn out to carry build_threadx.sh with no
build_threadx_sample.sh, so they were skipped despite having a driver:
cortex_m23, cortex_m33, cortex_m55 and cortex_m85. Reported, not fixed. Whether
those want a sample script is a separate question.

The expected-to-fail test now runs before the Arm test rather than after. arm9
and arm11 are on that list but carry no PORT_TARGET entry, so testing for Arm
first dropped them from the report entirely, reintroducing the same silence for
two ports that were already being named.

Verified with Arm Toolchain for Embedded 22.1.0, the version CI pins: 711 of 711
assembly sources, 185 of 185 common C sources for each of the nine cores
including cortex_r52, and 38 of 38 example builds linking, so the built set is
unchanged by this commit. The remaining driverless ports report as cortex_r52,
cortex_a5_smp, cortex_a7_smp and cortex_a9_smp, the three A profile SMP ports
having no example scripts and the R52 examples being driven by CMake. --help
still frames the intended lines, since the additions sit below the range it
selects by number.

Assisted-by: Claude Code (Opus 5) <noreply@anthropic.com>

scripts/check_clang.sh

@@ -142,7 +142,12 @@ declare -A PORT_TARGET=(
 # One core per architecture profile for the C sources. Compiling all of them
 # for every core would multiply the run time without adding coverage, since the
 # port headers differ by profile rather than by core.
-C_CORES="cortex_m0 cortex_m4 cortex_m23 cortex_m33 cortex_m55 cortex_a7 cortex_a53 cortex_r5"
+#
+# cortex_r52 earns a slot of its own next to cortex_r5 because Armv8-R AArch32
+# is a separate profile rather than a variant of Armv7-R. That port is written
+# by hand instead of generated from ports_arch, and its tx_port.h differs
+# accordingly, so cortex_r5 does not stand in for it.
+C_CORES="cortex_m0 cortex_m4 cortex_m23 cortex_m33 cortex_m55 cortex_a7 cortex_a53 cortex_r5 cortex_r52"
 
 # Example builds that are not expected to link, with the reason. Named by
 # their port directory, which covers both ports/ and ports_smp/. Listed
@@ -225,12 +230,37 @@ if [ "$no_examples" -eq 0 ]; then
     example_ok=0
     example_total=0
     example_known=""
+    example_nodriver=""
+    example_nosample=""
     for dir in ports/*/gnu/example_build ports_smp/*/gnu/example_build; do
-        [ -f "$dir/build_threadx.sh" ] && [ -f "$dir/build_threadx_sample.sh" ] || continue
+        [ -d "$dir" ] || continue
         core="$(echo "$dir" | cut -d/ -f2)"
+
+        # Anything on the expected-to-fail list is reported before any other
+        # filter is applied, so a name placed there can never drop out of the
+        # output. arm9 and arm11 are the cases that matter: they are Arm ports
+        # with example drivers, but they carry no PORT_TARGET entry, so the
+        # Arm test below would discard them.
         case " $EXAMPLES_EXPECTED_TO_FAIL " in
             *" $core "*) example_known="$example_known $core"; continue ;;
         esac
+
+        # Arm ports only, the same rule the assembly stage applies. Naming
+        # linux or mips32 as a gap here would be noise, not information.
+        [ -n "${PORT_TARGET[$core]:-}" ] || continue
+
+        # A driverless example is not covered by this stage, so say so rather
+        # than dropping out in silence. A port that is simply absent from the
+        # count reads as covered: the CMake based example builds under
+        # ports/cortex_r52 looked like part of the 35 while never being built.
+        if [ ! -f "$dir/build_threadx.sh" ]; then
+            example_nodriver="$example_nodriver $core"
+            continue
+        fi
+        if [ ! -f "$dir/build_threadx_sample.sh" ]; then
+            example_nosample="$example_nosample $core"
+            continue
+        fi
         example_total=$((example_total + 1))
 
         rm -f "$dir"/*.o "$dir"/*.a "$dir"/*.out "$dir"/*.map 2>/dev/null || true
@@ -252,6 +282,12 @@ if [ "$no_examples" -eq 0 ]; then
     if [ -n "$example_known" ]; then
         say "  known not to link, see the list at the top of this script:$example_known"
     fi
+    if [ -n "$example_nosample" ]; then
+        say "  has build_threadx.sh but no build_threadx_sample.sh, so not linked:$example_nosample"
+    fi
+    if [ -n "$example_nodriver" ]; then
+        say "  no script driver, so outside this stage:$example_nodriver"
+    fi
 fi
 # --------------------------------------------------------------------------
 say ""