configure: set the bindgen cross target

Implement a bash version of rust-bindgen rust_to_clang_target() to
convert from rust target to clang target.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20250924120426.2158655-8-marcandre.lureau@redhat.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/scripts/rust-to-clang-target.sh b/scripts/rust-to-clang-target.sh
new file mode 100644
index 0000000000..72db7e1300
--- /dev/null
+++ b/scripts/rust-to-clang-target.sh
@@ -0,0 +1,60 @@
+# Copyright (C) 2025 Red Hat, Inc.
+#
+# Based on rust_to_clang_target() from rust-bindgen.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+rust_to_clang_target() {
+    rust_target="$1"
+
+    # Split the string by hyphens
+    triple_parts=""
+    old_IFS="$IFS"
+    IFS='-'
+    for part in $rust_target; do
+        triple_parts="$triple_parts $part"
+    done
+    IFS="$old_IFS"
+    set -- $triple_parts
+
+    # RISC-V
+    case "$1" in
+        riscv32*)
+            set -- "riscv32" "${2}" "${3}" "${4}"
+            ;;
+        riscv64*)
+            set -- "riscv64" "${2}" "${3}" "${4}"
+            ;;
+    esac
+
+    # Apple
+    if [ "$2" = "apple" ]; then
+        if [ "$1" = "aarch64" ]; then
+            set -- "arm64" "${2}" "${3}" "${4}"
+        fi
+        if [ "$4" = "sim" ]; then
+            set -- "${1}" "${2}" "${3}" "simulator"
+        fi
+    fi
+
+    # ESP-IDF
+    if [ "$3" = "espidf" ]; then
+        set -- "${1}" "${2}" "elf" "${4}"
+    fi
+
+    # Reassemble the string
+    new_triple=""
+    first=1
+    for part in "$@"; do
+        if [ -n "$part" ]; then
+            if [ "$first" -eq 1 ]; then
+                new_triple="$part"
+                first=0
+            else
+                new_triple="$new_triple-$part"
+            fi
+        fi
+    done
+
+    echo "$new_triple"
+}