path: root/scripts/check_gcc.sh

#!/bin/bash
##############################################################################
# Copyright (c) 2026 Eclipse ThreadX contributors
#
# This program and the accompanying materials are made available under the
# terms of the MIT License which is available at
# https://opensource.org/licenses/MIT.
#
# AI Disclosure: This file was largely AI-generated by Claude Code (Opus 5).
# The AI-generated portions may be considered public domain (CC0-1.0)
# and not subject to the project's licence. The human contributor has
# reviewed and verified that the code is correct.
#
# SPDX-License-Identifier: MIT and CC0-1.0
##############################################################################

# Builds the Arm ports with the GNU toolchain, in seven stages: assemble every
# assembly source of every Arm gnu port, assemble again the parts guarded by
# feature macros, compile the common C sources for one core per architecture
# profile, compile the module manager C sources once per Arm module port, link
# the example builds, both the script-driven ones and those driven by CMake,
# and finally assert that the option combinations the Cortex-R52 port refuses
# are in fact refused. Only the linking stages need a target C library.
#
#     scripts/check_gcc.sh                          # both drivers from PATH
#     scripts/check_gcc.sh --arm-none-eabi /path/to/toolchain/bin \
#                          --aarch64-none-elf /path/to/toolchain/bin
#
# Options:
#     --arm-none-eabi <path>     arm-none-eabi-gcc, or the directory holding it.
#                                Defaults to $ARM_NONE_EABI_GCC then to PATH.
#     --aarch64-none-elf <path>  aarch64-none-elf-gcc, or its directory.
#                                Defaults to $AARCH64_NONE_ELF_GCC then to PATH.
#     --asm-only                 Skip the C sources and the example builds.
#     --no-examples              Skip the example builds.
#     --quiet                    Print only failures and the summary.
#
# Exit status is 0 when everything builds and 1 otherwise.
#
# Why this exists: GCC 14 on Linux is the project's default compiler, it is
# what the gnu ports exist for, and it is what nearly every downstream user
# builds with -- and until this script landed, nothing in CI compiled a line
# of any port with it. The only cross-compilation check that ran was the LLVM
# one, so the ATfE path was better guarded than the GNU one, on ports whose
# directory is literally named gnu.
#
# This is the companion to scripts/check_clang.sh and deliberately mirrors it
# stage for stage. They are two scripts rather than one with a --toolchain flag
# because the flag surface differs (a prefixed driver against --target=), the
# C library differs, and the set of examples that can link differs. Folding
# them together makes it easy to weaken one check while working on the other.
#
# It compiles and links; it executes nothing. The Cortex-R52 FVP ctest suite is
# a separate matter, and the RISC-V, MIPS, RX and ARC families are outside it
# entirely -- every skip is printed by name below.
#
# Arm GNU toolchain releases:
#     https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads

set -u

cd "$(dirname "$(realpath "$0")")/.."

# Two toolchains, not one. Arm ships arm-none-eabi (AArch32: every M and R
# profile core and the A32 A-profile ports) and aarch64-none-elf as separate
# downloads, and PORT_TARGET below maps every port to one of exactly those two
# triples. Both are required: making a missing one a soft skip would let a run
# cover half the tree and still say "all checks passed", which is the failure
# this script was written to end.
CC_ARM="${ARM_NONE_EABI_GCC:-}"
CC_AARCH64="${AARCH64_NONE_ELF_GCC:-}"
asm_only=0
no_examples=0
quiet=0

while [ "$#" -gt 0 ]; do
    case "$1" in
        --arm-none-eabi)
            [ "$#" -ge 2 ] || { echo "Error: --arm-none-eabi needs a path" >&2; exit 2; }
            CC_ARM="$2"; shift 2 ;;
        --aarch64-none-elf)
            [ "$#" -ge 2 ] || { echo "Error: --aarch64-none-elf needs a path" >&2; exit 2; }
            CC_AARCH64="$2"; shift 2 ;;
        --asm-only)    asm_only=1; no_examples=1; shift ;;
        --no-examples) no_examples=1; shift ;;
        --quiet)       quiet=1; shift ;;
        -h|--help)     sed -n '17,36p' "$0"; exit 0 ;;
        *) echo "Error: unknown option '$1'" >&2; exit 2 ;;
    esac
done

say()  { [ "$quiet" -eq 1 ] || echo "$@"; }
fail() { echo "  FAIL: $*"; }

# The C stages treat any compiler output as a failure, and a #pragma message is
# a deliberate notice to callers rather than a defect in the file that carries
# it -- txm_module_manager_absolute_load.c deprecates itself in favour of the
# extended entry point, and the module manager stage compiles it once per port.
#
# check_clang.sh suppresses these at the compiler with -Wno-#pragma-messages.
# GCC has no equivalent: the note is unconditional, and neither -Wno-pragmas
# nor any other -W option silences it -- verified with 14.3.rel1. So it is
# filtered out of the output here instead, along with the source quote and
# caret GCC prints beneath it. The skip ends at the next line that starts a
# diagnostic of its own, so an error following a waived note is still reported.
strip_pragma_messages() {
    awk '
        /note: .#pragma message:/ { skip = 1; next }
        skip && /^ *[0-9]* *\|/  { next }
        { skip = 0; print }
    '
}

# Accept either the driver itself or the directory holding it, since a
# toolchain is unpacked as a tree and naming its bin directory is the natural
# thing to reach for. Resolve to an absolute path: the example stages run the
# build scripts from inside their own directories, so a relative path would
# stop resolving there.
resolve_gcc() {
    triple="$1"
    given="$2"

    if [ -z "$given" ]; then
        command -v "${triple}-gcc" >/dev/null 2>&1 || return 1
        command -v "${triple}-gcc"
        return 0
    fi
    if [ -d "$given" ]; then
        for candidate in "$given/${triple}-gcc" "$given/bin/${triple}-gcc"; do
            [ -x "$candidate" ] && { realpath "$candidate"; return 0; }
        done
        return 1
    fi
    [ -x "$given" ] || return 1
    realpath "$given"
}

missing=""
CC_ARM="$(resolve_gcc arm-none-eabi "$CC_ARM")"     || missing="$missing arm-none-eabi"
CC_AARCH64="$(resolve_gcc aarch64-none-elf "$CC_AARCH64")" || missing="$missing aarch64-none-elf"

if [ -n "$missing" ]; then
    echo "Error: compiler(s) not found:$missing"
    echo "Pass --arm-none-eabi and --aarch64-none-elf, set ARM_NONE_EABI_GCC and"
    echo "AARCH64_NONE_ELF_GCC, or put both drivers on PATH. Downloads:"
    echo "  https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads"
    exit 1
fi

say ""
say "Using: $CC_ARM"
say "       $("$CC_ARM" --version | head -1)"
say "       $CC_AARCH64"
say "       $("$CC_AARCH64" --version | head -1)"

# The example build scripts and the CMake toolchain file call the drivers by
# their bare prefixed names, so both bin directories go on PATH for the linking
# stages. Done once, here, rather than per stage: a second toolchain arriving
# on PATH halfway through a run is exactly the kind of difference that makes a
# failure irreproducible.
PATH="$(dirname "$CC_ARM"):$(dirname "$CC_AARCH64"):$PATH"
export PATH

# Pick the driver for a port from its triple, so the map below stays the single
# place a port's architecture is decided.
cc_for() {
    case "$1" in
        aarch64-none-elf) echo "$CC_AARCH64" ;;
        *)                echo "$CC_ARM" ;;
    esac
}

# Each port directory is mapped explicitly to a target triple and CPU. Do not
# replace this with prefix matching: cortex_a5* also matches cortex_a53 and
# cortex_a55, which are AArch64, and assembling those as ARM32 produces a flood
# of misleading errors.
#
# Copied verbatim from scripts/check_clang.sh. Keep the two identical -- a port
# covered by one check and not the other is worse than one covered by neither,
# because the checks list implies parity that does not exist.
declare -A PORT_TARGET=(
 [cortex_m0]="arm-none-eabi cortex-m0 -mthumb"
 [cortex_m0+]="arm-none-eabi cortex-m0plus -mthumb"
 [cortex_m3]="arm-none-eabi cortex-m3 -mthumb"
 [cortex_m4]="arm-none-eabi cortex-m4 -mthumb"
 [cortex_m7]="arm-none-eabi cortex-m7 -mthumb"
 [cortex_m23]="arm-none-eabi cortex-m23 -mthumb"
 [cortex_m33]="arm-none-eabi cortex-m33 -mthumb"
 [cortex_m52]="arm-none-eabi cortex-m52 -mthumb -mfloat-abi=hard"
 [cortex_m55]="arm-none-eabi cortex-m55 -mthumb -mfloat-abi=hard"
 [cortex_m85]="arm-none-eabi cortex-m85 -mthumb -mfloat-abi=hard"
 [cortex_a5]="arm-none-eabi cortex-a5"
 [cortex_a7]="arm-none-eabi cortex-a7"
 [cortex_a8]="arm-none-eabi cortex-a8"
 [cortex_a9]="arm-none-eabi cortex-a9"
 [cortex_a12]="arm-none-eabi cortex-a12"
 [cortex_a15]="arm-none-eabi cortex-a15"
 [cortex_a17]="arm-none-eabi cortex-a17"
 [cortex_a5_smp]="arm-none-eabi cortex-a5"
 [cortex_a7_smp]="arm-none-eabi cortex-a7"
 [cortex_a9_smp]="arm-none-eabi cortex-a9"
 [cortex_r4]="arm-none-eabi cortex-r4"
 [cortex_r5]="arm-none-eabi cortex-r5"
 [cortex_r52]="arm-none-eabi cortex-r52"
 [cortex_a34]="aarch64-none-elf cortex-a34"
 [cortex_a35]="aarch64-none-elf cortex-a35"
 [cortex_a53]="aarch64-none-elf cortex-a53"
 [cortex_a55]="aarch64-none-elf cortex-a55"
 [cortex_a57]="aarch64-none-elf cortex-a57"
 [cortex_a65]="aarch64-none-elf cortex-a65"
 [cortex_a65ae]="aarch64-none-elf cortex-a65ae"
 [cortex_a72]="aarch64-none-elf cortex-a72"
 [cortex_a73]="aarch64-none-elf cortex-a73"
 [cortex_a75]="aarch64-none-elf cortex-a75"
 [cortex_a76]="aarch64-none-elf cortex-a76"
 [cortex_a76ae]="aarch64-none-elf cortex-a76ae"
 [cortex_a77]="aarch64-none-elf cortex-a77"
 [cortex_a34_smp]="aarch64-none-elf cortex-a34"
 [cortex_a35_smp]="aarch64-none-elf cortex-a35"
 [cortex_a53_smp]="aarch64-none-elf cortex-a53"
 [cortex_a55_smp]="aarch64-none-elf cortex-a55"
 [cortex_a57_smp]="aarch64-none-elf cortex-a57"
 [cortex_a65_smp]="aarch64-none-elf cortex-a65"
 [cortex_a65ae_smp]="aarch64-none-elf cortex-a65ae"
 [cortex_a72_smp]="aarch64-none-elf cortex-a72"
 [cortex_a73_smp]="aarch64-none-elf cortex-a73"
 [cortex_a75_smp]="aarch64-none-elf cortex-a75"
 [cortex_a76_smp]="aarch64-none-elf cortex-a76"
 [cortex_a76ae_smp]="aarch64-none-elf cortex-a76ae"
 [cortex_a77_smp]="aarch64-none-elf cortex-a77"
 [cortex_a78_smp]="aarch64-none-elf cortex-a78"
)

# Assembly guarded by a feature macro is invisible to the stage above, which
# assembles with default flags and so lets the preprocessor discard every #ifdef
# block before the assembler sees it. These are the macros a user can turn on;
# each file carrying one is assembled again with it defined.
#
# This is not hypothetical, and it is not only clang's finding. The Cortex-M23
# module manager carried "POP {r0, lr}" in exactly these paths -- invalid on
# Armv8-M Baseline, where the 16-bit POP takes r0-r7 and pc only -- for six
# months after the identical fix landed in its non-module sibling, because no
# glob in either script reached ports_module until #672.
FEATURE_MACROS="TX_ENABLE_VFP_SUPPORT TX_ENABLE_FIQ_SUPPORT TX_LOW_POWER
                TX_ENABLE_EXECUTION_CHANGE_NOTIFY TX_EXECUTION_PROFILE_ENABLE"

# TX_ENABLE_IRQ_NESTING and TX_ENABLE_FIQ_NESTING are deliberately not here.
# They guard no assembly in the trees this script walks: the nesting start and
# end routines are separate files compiled unconditionally, and the macros only
# feed the TX_PORT_SPECIFIC_BUILD_OPTIONS bitfield in tx_port.h. Adding them
# would assemble nothing new and imply coverage that does not exist.

# Extra flags for the VFP paths, per core.
#
# check_clang.sh's equivalent map has one entry and a comment saying "Do not
# extend this to the A profile ports ... their defaults are already correct."
# That is true of clang and false of GCC, so do not copy that comment here.
# arm-none-eabi-gcc defaults to -mfloat-abi=soft, which disables the FPU
# outright, and every VFP file then fails with
#
#     selected processor does not support 'vmrs r1,FPSCR' in ARM mode
#
# -mfloat-abi=hard alone is the fix, and it is the right one: it selects the
# core's own default FPU rather than naming one. Naming a -d16 FPU is the trap
# the clang script warns about -- the A-profile paths save D16-D31, which exist
# only on a 32-register FPU, so a -d16 choice turns 28 working files into
# "register expected".
#
# Cortex-R4 is the exception, in both scripts and for the same reason: its FPU
# is an option rather than part of the core, so -mfloat-abi=hard alone gives
# "selected architecture lacks an FPU" and an explicit -mfpu is required. The
# value matches check_clang.sh's, so the two scripts say the same thing about
# the same port.
#
# Every entry below was measured against arm-gnu-toolchain 14.3.rel1. A core
# that acquires a VFP-guarded file without an entry here fails loudly rather
# than silently, which is the intended behaviour.
declare -A VFP_EXTRA=(
    [cortex_a5]="-mfloat-abi=hard"
    [cortex_a7]="-mfloat-abi=hard"
    [cortex_a8]="-mfloat-abi=hard"
    [cortex_a9]="-mfloat-abi=hard"
    [cortex_a12]="-mfloat-abi=hard"
    [cortex_a15]="-mfloat-abi=hard"
    [cortex_a17]="-mfloat-abi=hard"
    [cortex_a5_smp]="-mfloat-abi=hard"
    [cortex_a7_smp]="-mfloat-abi=hard"
    [cortex_a9_smp]="-mfloat-abi=hard"
    [cortex_r4]="-mfpu=vfpv3-d16 -mfloat-abi=softfp"
    [cortex_r5]="-mfloat-abi=hard"
    [cortex_r52]="-mfloat-abi=hard"
)

# 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.
#
# 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 driven by CMake rather than by a build_threadx.sh pair. These
# are covered by their own stage below, so the script-driven loop passes over
# them without reporting them as a gap.
CMAKE_EXAMPLE_CORES="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
# explicitly rather than silently skipped, so the gaps stay visible.
#
# The same four as check_clang.sh, and the reason there is stated in terms of
# GNU tooling because that is where it was reproduced:
#
#   their linker scripts define the .init and .fini sections but not the _init
#   and _fini symbols. Those come from crti.o and crtn.o, which -nostartfiles
#   leaves out, so newlib's fini.c cannot resolve them and the link ends with
#   "undefined reference to `_fini'".
#
# The 27 AArch64 examples failed the same way until #673, which links crti.o
# and crtn.o back. They are deliberately absent from this list: they link.
EXAMPLES_EXPECTED_TO_FAIL="arm9 arm11 cortex_r4 cortex_r5"

failures=0
skipped=""

# --------------------------------------------------------------------------
say ""
say "== Assembly sources of every Arm gnu port =="

total=0
# The module ports keep their assembly in module_manager/src, not src.
# check_clang.sh read ports_module/*/gnu/src until #672; that directory does
# not exist, the [ -d ] guard skipped it in silence, and 116 files across nine
# Arm module ports were assembled by no check with either compiler. This script
# has never had that hole and must not acquire it.
for dir in ports/*/gnu/src ports_smp/*/gnu/src ports_module/*/gnu/module_manager/src; do
    [ -d "$dir" ] || continue
    core="$(echo "$dir" | cut -d/ -f2)"
    spec="${PORT_TARGET[$core]:-}"
    if [ -z "$spec" ]; then
        skipped="$skipped $core"
        continue
    fi
    # shellcheck disable=SC2086
    set -- $spec
    target="$1"; cpu="$2"; shift 2; extra="$*"
    CC="$(cc_for "$target")"

    for src in "$dir"/*.S "$dir"/*.s; do
        [ -f "$src" ] || continue
        total=$((total + 1))
        output="$("$CC" -mcpu="$cpu" $extra -c "$src" -o /dev/null 2>&1)"
        if [ -n "$output" ]; then
            fail "$src"
            echo "$output" | sed 's/^/        /'
            failures=$((failures + 1))
        fi
    done
done
say "  $((total - failures)) of $total assembled"
if [ -n "$skipped" ]; then
    say "  not Arm, skipped:$(echo $skipped | tr ' ' '\n' | sort -u | tr '\n' ' ')"
    say "  (arm9 and arm11 are Arm; they are skipped for having no PORT_TARGET entry)"
fi

# --------------------------------------------------------------------------
say ""
say "== Assembly behind feature macros =="

for macro in $FEATURE_MACROS; do
    macro_total=0
    macro_bad=0
    for src in $(grep -rl "$macro" ports/*/gnu/src/*.S ports_smp/*/gnu/src/*.S \
                 ports_module/*/gnu/module_manager/src/*.S \
                 2>/dev/null | sort); do
        core="$(echo "$src" | cut -d/ -f2)"
        spec="${PORT_TARGET[$core]:-}"
        [ -n "$spec" ] || continue
        # shellcheck disable=SC2086
        set -- $spec
        target="$1"; cpu="$2"; shift 2; extra="$*"
        CC="$(cc_for "$target")"

        # The FPU flags apply to the VFP paths only; the other macros guard no
        # floating-point code and do not need them.
        fpu=""
        if [ "$macro" = "TX_ENABLE_VFP_SUPPORT" ]; then
            fpu="${VFP_EXTRA[$core]:-}"
        fi

        macro_total=$((macro_total + 1))
        output="$("$CC" -mcpu="$cpu" $extra $fpu \
                  -D"$macro" -c "$src" -o /dev/null 2>&1)"
        if [ -n "$output" ]; then
            fail "$src with -D$macro"
            # Not filtered on "error": GCC prefixes its diagnostics with an
            # "Assembler messages:" line and a missing tool says nothing of the
            # kind, so filtering would hide the case worth seeing.
            echo "$output" | head -4 | sed 's/^/        /'
            macro_bad=$((macro_bad + 1))
            failures=$((failures + 1))
        fi
    done
    if [ "$macro_total" -eq 0 ]; then
        say "  $macro: no assembly is guarded by it"
    else
        say "  $macro: $((macro_total - macro_bad)) of $macro_total assembled"
    fi
done

# --------------------------------------------------------------------------
if [ "$asm_only" -eq 0 ]; then
    say ""
    say "== Common C sources, one core per architecture profile =="

    for core in $C_CORES; do
        spec="${PORT_TARGET[$core]:-}"
        [ -n "$spec" ] || continue
        # shellcheck disable=SC2086
        set -- $spec
        target="$1"; cpu="$2"; shift 2; extra="$*"
        CC="$(cc_for "$target")"

        count=0; bad=0
        for src in common/src/*.c; do
            count=$((count + 1))
            output="$("$CC" -mcpu="$cpu" $extra \
                      -Iports/"$core"/gnu/inc -Icommon/inc -c "$src" -o /dev/null 2>&1)"
            if [ -n "$output" ]; then
                fail "$core: $src"
                echo "$output" | head -4 | sed 's/^/        /'
                bad=$((bad + 1)); failures=$((failures + 1))
            fi
        done
        say "  $core: $((count - bad)) of $count compiled"
    done
fi

# --------------------------------------------------------------------------
if [ "$asm_only" -eq 0 ]; then
    say ""
    say "== Module manager C sources, one per Arm module port =="

    # #689 added this stage to check_clang.sh alone, so the module manager C
    # stayed unbuilt by the project's declared default compiler: 28 files of
    # portable module manager under common_modules, plus the three to nine
    # per-port files under ports_module/<core>/gnu/module_manager/src. This is
    # the GCC half, and it is deliberately the same stage -- same ports, same
    # headers, same counts -- because a port covered by one check and not the
    # other implies a parity the checks list does not have.
    #
    # Each module port ships its own tx_port.h and txm_module_port.h, carrying
    # the control-block extensions the dispatch code needs, so a port is
    # compiled against its own headers rather than the base port's.
    module_skipped=""
    for dir in ports_module/*/gnu/module_manager/src; do
        [ -d "$dir" ] || continue
        core="$(echo "$dir" | cut -d/ -f2)"
        spec="${PORT_TARGET[$core]:-}"
        if [ -z "$spec" ]; then
            module_skipped="$module_skipped $core"
            continue
        fi

        inc="ports_module/$core/gnu/inc"
        if [ ! -f "$inc/tx_port.h" ] || [ ! -f "$inc/txm_module_port.h" ]; then
            module_skipped="$module_skipped $core(headers)"
            continue
        fi

        # shellcheck disable=SC2086
        set -- $spec
        target="$1"; cpu="$2"; shift 2; extra="$*"
        CC="$(cc_for "$target")"

        # An SMP port's control blocks come from common_smp; pairing it with the
        # single-core headers hides _tx_thread_smp_protect behind an implicit
        # declaration instead of compiling the port that is actually shipped.
        case "$core" in
            *_smp) kernel_inc="common_smp/inc" ;;
            *)     kernel_inc="common/inc" ;;
        esac

        # The TrustZone ports carry cmse_nonsecure_entry, which needs -mcmse to
        # be honoured rather than ignored.
        port_extra=""
        if [ -f "$inc/tx_secure_interface.h" ]; then
            port_extra="-mcmse"
        fi

        count=0; bad=0
        for src in common_modules/module_manager/src/*.c "$dir"/*.c; do
            [ -f "$src" ] || continue
            count=$((count + 1))
            output="$("$CC" -mcpu="$cpu" $extra $port_extra \
                      -I"$inc" -I"$kernel_inc" -Icommon_modules/inc \
                      -Icommon_modules/module_manager/inc \
                      -c "$src" -o /dev/null 2>&1 | strip_pragma_messages)"
            if [ -n "$output" ]; then
                fail "$core: $src"
                # Show the error lines when there are any, and otherwise
                # whatever the compiler did say -- a FAIL with nothing under it
                # sends the reader off to reproduce the command by hand.
                if echo "$output" | grep -q "error:"; then
                    echo "$output" | grep "error:" | head -3 | sed 's/^/        /'
                else
                    echo "$output" | head -3 | sed 's/^/        /'
                fi
                bad=$((bad + 1)); failures=$((failures + 1))
            fi
        done
        say "  $core: $((count - bad)) of $count compiled"
    done
    if [ -n "$module_skipped" ]; then
        say "  no target mapping, skipped:$module_skipped"
    fi
fi

# --------------------------------------------------------------------------
if [ "$no_examples" -eq 0 ]; then
    say ""
    say "== Example builds, linked with GNU ld =="

    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
        [ -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

        # Covered by the CMake stage below rather than here.
        case " $CMAKE_EXAMPLE_CORES " in
            *" $core "*) continue ;;
        esac

        # 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.
        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))

        # Clean on both sides. A stale sample_threadx.out from a previous
        # toolchain makes a failed link report success, because the success
        # test below is the existence of the output file rather than the exit
        # status of the driver.
        rm -f "$dir"/*.o "$dir"/*.a "$dir"/*.out "$dir"/*.map 2>/dev/null || true

        # TOOLCHAIN is *unset*, not set: the build scripts already default to
        # GNU with `: "${TOOLCHAIN:=gnu}"`, and a stray TOOLCHAIN=atfe from a
        # developer's shell or an earlier command would otherwise make this
        # stage silently check the other compiler.
        log="$(cd "$dir" && unset TOOLCHAIN && ./build_threadx.sh 2>&1 && \
                                              ./build_threadx_sample.sh 2>&1)" || true

        if [ -f "$dir/sample_threadx.out" ]; then
            example_ok=$((example_ok + 1))
        else
            fail "$core: example build produced no image"
            # Not filtered on "error": a missing tool reports "command not
            # found" or "Permission denied", and filtering hid exactly that.
            echo "$log" | tail -6 | sed 's/^/        /'
            failures=$((failures + 1))
        fi
        rm -f "$dir"/*.o "$dir"/*.a "$dir"/*.out "$dir"/*.map 2>/dev/null || true
    done
    say "  $example_ok of $example_total example builds linked"
    if [ -n "$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

# --------------------------------------------------------------------------
# The Cortex-R52 examples are built by CMake, so they need a toolchain file
# rather than the build_threadx.sh pair. Same compiler, same purpose as the
# stage above.
if [ "$no_examples" -eq 0 ]; then
    say ""
    say "== CMake example builds, linked with GNU ld =="

    if ! command -v cmake >/dev/null 2>&1 || ! command -v ninja >/dev/null 2>&1; then
        say "  skipped: cmake and ninja are both required"
    else
        for core in $CMAKE_EXAMPLE_CORES; do
            build_dir="$(mktemp -d)"
            # ARM_TOOLCHAIN_PATH follows --arm-none-eabi, so this stage uses
            # the same compiler as every other stage rather than the absolute
            # path cmake/cortex_r52.cmake pins by default.
            if cmake -S . -B "$build_dir" -G Ninja \
                    -DCMAKE_TOOLCHAIN_FILE="cmake/${core}.cmake" \
                    -DARM_TOOLCHAIN_PATH="$(dirname "$CC_ARM")" \
                    -DTX_R52_BUILD_FVP_EXAMPLE=ON \
                    -DTX_R52_ENABLE_MPU=ON >"$build_dir/configure.log" 2>&1; then
                # Read the image list from the generated graph instead of
                # repeating it here, so adding a target cannot silently escape
                # this check. The images are EXCLUDE_FROM_ALL, so "ninja" alone
                # would build none of them.
                #
                # The cmake_object_order_depends_target_* entries are CMake's
                # own ordering phonies, one per real image and named after it.
                # Counting those doubled the total and reported ten images built
                # where there are five.
                images="$(ninja -C "$build_dir" -t targets all 2>/dev/null \
                          | grep -oE '^[A-Za-z0-9_]+\.elf' \
                          | grep -v '^cmake_' | sort -u)"
                if [ -z "$images" ]; then
                    fail "$core: no .elf targets found in the CMake graph"
                    failures=$((failures + 1))
                else
                    built=0; total=0
                    for image in $images; do
                        total=$((total + 1))
                        if ninja -C "$build_dir" "$image" \
                                >"$build_dir/$image.log" 2>&1; then
                            built=$((built + 1))
                        else
                            fail "$core: $image did not build"
                            tail -6 "$build_dir/$image.log" | sed 's/^/        /'
                            failures=$((failures + 1))
                        fi
                    done
                    say "  $core: $built of $total images linked"
                fi
            else
                fail "$core: CMake configure failed"
                tail -6 "$build_dir/configure.log" | sed 's/^/        /'
                failures=$((failures + 1))
            fi
            rm -rf "$build_dir"
        done
    fi
fi

# --------------------------------------------------------------------------
# Option combinations the port refuses at configure time.
#
# ports/cortex_r52/gnu/CMakeLists.txt rejects two combinations outright rather
# than letting them reach the compiler. Both are cheap to get wrong in a way
# that is invisible: a typo in a variable name makes the condition constant,
# and a guard that never fires is indistinguishable from one that is never
# tripped. So these assert the exit status AND the text, because a guard that
# fires for the wrong reason would otherwise pass.
#
# No example flags are needed: the port CMakeLists is included by the toolchain
# file alone, so the guards are reached without configuring anything else. That
# keeps the stage to three configures, two of which stop almost immediately.
#
# The third is the positive counterpart, and it is not decoration: a guard that
# rejects everything would satisfy both negative cases on its own. Asserting
# that the supported combination still configures is what distinguishes a guard
# that works from one that is merely always on.
#
# This is the only negative check in the script. Everything else here asserts
# that something builds; this stage asserts that two things refuse to, and that
# a third still does not.
if [ "$asm_only" -eq 0 ]; then
    say ""
    say "== Option combinations the Cortex-R52 port must refuse =="

    if ! command -v cmake >/dev/null 2>&1; then
        say "  skipped: cmake is required"
    else
        # name | expected text in the error | options
        refuse_case() {
            case_name="$1"; want="$2"; shift 2
            build_dir="$(mktemp -d)"
            if cmake -S . -B "$build_dir" -G Ninja \
                    -DCMAKE_TOOLCHAIN_FILE=cmake/cortex_r52.cmake \
                    -DARM_TOOLCHAIN_PATH="$(dirname "$CC_ARM")" \
                    "$@" >"$build_dir/configure.log" 2>&1; then
                fail "$case_name: configure succeeded, but this combination cannot build"
                failures=$((failures + 1))
            elif ! grep -q "$want" "$build_dir/configure.log"; then
                fail "$case_name: configure failed, but not on the expected guard"
                fail "  wanted text: $want"
                tail -6 "$build_dir/configure.log" | sed 's/^/        /'
                failures=$((failures + 1))
            else
                say "  $case_name: refused"
            fi
            rm -rf "$build_dir"
        }

        refuse_case "VFP without a hard float ABI" \
                    "TX_R52_ENABLE_VFP requires TX_R52_FLOAT_ABI=hard" \
                    -DTX_R52_ENABLE_VFP=ON

        refuse_case "FIQ nesting without FIQ" \
                    "TX_R52_ENABLE_FIQ_NESTING requires TX_R52_ENABLE_FIQ" \
                    -DTX_R52_ENABLE_FIQ_NESTING=ON

        # The counterpart: the supported spelling of the first case must still
        # configure, so a guard cannot pass this stage by rejecting everything.
        build_dir="$(mktemp -d)"
        if cmake -S . -B "$build_dir" -G Ninja \
                -DCMAKE_TOOLCHAIN_FILE=cmake/cortex_r52.cmake \
                -DARM_TOOLCHAIN_PATH="$(dirname "$CC_ARM")" \
                -DTX_R52_ENABLE_VFP=ON -DTX_R52_FLOAT_ABI=hard \
                -DTX_R52_ENABLE_FIQ=ON -DTX_R52_ENABLE_FIQ_NESTING=ON \
                >"$build_dir/configure.log" 2>&1; then
            say "  the supported combination: accepted"
        else
            fail "the supported combination was refused"
            tail -6 "$build_dir/configure.log" | sed 's/^/        /'
            failures=$((failures + 1))
        fi
        rm -rf "$build_dir"
    fi
fi

# --------------------------------------------------------------------------
say ""
if [ "$failures" -eq 0 ]; then
    say "All GNU toolchain checks passed."
    exit 0
fi

echo "$failures GNU toolchain check(s) failed."
exit 1