scripts/utils: Build a list of "excluded" libc APIs

This script generates a list of exported symbols (functions, global
variables, static inlines and CPP names) which are present in picolibc but
not present in the minimal C library.

These symbols shall not be used by the "core Zephyr kernel"; the
construction of a script that detects use of the is left as an exercise to
the reader.

Signed-off-by: Keith Packard <[email protected]>

scripts/utils/find_id.cocci

@@ -0,0 +1,23 @@
+virtual patch
+virtual report
+
+@initialize:python@
+@@
+
+@find_id@
+identifier id;
+type ty;
+parameter list[nb_params] params;
+position p;
+@@
+(
+  ty id@p(params);
+|
+  extern ty id@p;
+)
+
+@script:python@
+id << find_id.id;
+p << find_id.p;
+@@
+print("identifier %s %s %s" % (id, p[0].file, p[0].line))

scripts/utils/gen-libc-exclude

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+HERE=`dirname "$0"`
+
+if [ -z "$ZEPHYR_SDK_INSTALL_DIR" ]; then
+    echo 'Must define ZEPHYR_SDK_INSTALL_DIR' 1>&2
+    exit 1
+fi
+
+if [ -z "$ZEPHYR_BASE" ]; then
+    echo 'Must define ZEPHYR_BASE' 1>&2
+    exit 1
+fi
+
+gen_syms() {
+    while read i; do
+	spatch --macro-file "$HERE"/libc-macros.h -sp-file "$HERE"/find_id.cocci "$i" 2>/dev/null |
+	    awk '/identifier/ { if ($2 !~ "_.*") print $2; }'
+	grep '^[ \t]*#[ \t]*\(define\|undef\)[ \t][ \t]*[A-Za-z]' "$i" |
+	    sed 's/^[ \t]*#[ \t]*\(define\|undef\)[ \t][ \t]*\([_A-Za-z][_A-Za-z0-9]*\).*$/\1 \2/' |
+	    awk '{ if ($1 == "define") defs[$2] = 1; else defs[$2] = 0; } END { for (id in defs) if (defs[id]) print id; }'
+    done | (LANG=C sort -u)
+}
+
+TMPDIR=`mktemp -d $PWD/gen-libc.XXXXXXXX`
+trap "rm -r $TMPDIR" EXIT
+
+MINIMAL_LIBC_INCLUDE="$ZEPHYR_BASE"/lib/libc/minimal/include
+POSIX_INCLUDE="$ZEPHYR_BASE"/include/zephyr/posix
+MINIMAL_LIBC_SYMS="$TMPDIR"/minimal-names
+
+find "$MINIMAL_LIBC_INCLUDE" "$POSIX_INCLUDE" -type f | gen_syms > "$MINIMAL_LIBC_SYMS"
+
+PICOLIBC_INCLUDE="$ZEPHYR_SDK_INSTALL_DIR"/arm-zephyr-eabi/picolibc/include
+PICOLIBC_LIBC_SYMS="$TMPDIR"/picolibc-names
+
+find "$PICOLIBC_INCLUDE" -type f | gen_syms > "$PICOLIBC_LIBC_SYMS"
+
+LANG=C comm -23 "$PICOLIBC_LIBC_SYMS" "$MINIMAL_LIBC_SYMS"

scripts/utils/libc-macros.h

@@ -0,0 +1 @@
+#define __printf_like(a,b)