Kbuild fixes for v4.18

- introduce __diag_* macros and suppress -Wattribute-alias warnings from GCC 8
 
 - fix stack protector test script for x86_64
 
 - fix line number handling in Kconfig
 
 - document that '#' starts a comment in Kconfig
 
 - handle P_SYMBOL property in dump debugging of Kconfig
 
 - correct help message of LD_DEAD_CODE_DATA_ELIMINATION
 
 - fix occasional segmentation faults in Kconfig
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQIcBAABAgAGBQJbN450AAoJED2LAQed4NsGFdAP/0fc2NhkzQMvz1EBEc2n93LC
 FUXew75tsX2ZewssoLzb4Iepkb/mHU+fjhBaE65S+Xu2/6mNfId9a7HAtywvFyO2
 ZUQPXHjMHnLEPRKuzQy34uCy9/wWCiqi8rpWUsOEohmNIcLaF0vMZf5Ifod7wIr7
 pnix3b9Q+dY+l49TSsSv4MX7F9qs5fXRhEarcQ3jYEb3yRUEXgmli3hV1wRita/n
 tJhFDiIdJDeISDkgmHUuOhjFnv5Yf3WJTXi/ILZ2zvpGjjqNDAwxtyzGnPMShQEc
 fxk3/1nkg9h/ScVAaGavrYYmiiH8XsqWY2q6p52jTK3kD+yTXaVakPSmxw8UHImh
 aNWQutzMF8GYEsb+ld1ncsNrwfgd40mA25mEyb/ZPSw2IdNBrXtIVbw7XiBLi8eH
 recAlRN0MouzD7+sXafgtoKopqanQbB/rMqDO4ULfnVvZLWDmZVbfreCc+qrJtiJ
 mqydBMUVxrvB+qf5SHQ7WlDmXWHY1xQuxXzS0gRVGT14EsyD6yhC2D62pEHnB7uG
 zE1pGemOCzOlGY6nDAbtQVR1n5AAWEZYveZXUuFn+vuqR7ZtYxCFUFOS0u621zFI
 HMI9B81ifdNV2efT2VTVi6Tnnvn44sAXOYjaULX6566EyX0/mOL5CWZlTqn5SKOn
 PwNxc7ZeCylTbkZww2c4
 =oABr
 -----END PGP SIGNATURE-----

Merge tag 'kbuild-fixes-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - introduce __diag_* macros and suppress -Wattribute-alias warnings
   from GCC 8

 - fix stack protector test script for x86_64

 - fix line number handling in Kconfig

 - document that '#' starts a comment in Kconfig

 - handle P_SYMBOL property in dump debugging of Kconfig

 - correct help message of LD_DEAD_CODE_DATA_ELIMINATION

 - fix occasional segmentation faults in Kconfig

* tag 'kbuild-fixes-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: loop boundary condition fix
  kbuild: reword help of LD_DEAD_CODE_DATA_ELIMINATION
  kconfig: handle P_SYMBOL in print_symbol()
  kconfig: document Kconfig source file comments
  kconfig: fix line numbers for if-entries in menu tree
  stack-protector: Fix test with 32-bit userland and CONFIG_64BIT=y
  powerpc: Remove -Wattribute-alias pragmas
  disable -Wattribute-alias warning for SYSCALL_DEFINEx()
  kbuild: add macro for controlling warnings to linux/compiler.h

scripts/gcc-x86_64-has-stack-protector.sh

@@ -1,4 +1,4 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
-echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -O0 -mcmodel=kernel -fno-PIE -fstack-protector - -o - 2> /dev/null | grep -q "%gs"
+echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -m64 -O0 -mcmodel=kernel -fno-PIE -fstack-protector - -o - 2> /dev/null | grep -q "%gs"

scripts/kconfig/expr.h

@@ -171,6 +171,9 @@ struct symbol {
  * config BAZ
  *         int "BAZ Value"
  *         range 1..255
+ *
+ * Please, also check zconf.y:print_symbol() when modifying the
+ * list of property types!
  */
 enum prop_type {
 	P_UNKNOWN,

scripts/kconfig/preprocess.c

@@ -156,7 +156,7 @@ static char *do_shell(int argc, char *argv[])
 		nread--;
 
 	/* remove trailing new lines */
-	while (buf[nread - 1] == '\n')
+	while (nread > 0 && buf[nread - 1] == '\n')
 		nread--;
 
 	buf[nread] = 0;

scripts/kconfig/zconf.y

@@ -31,7 +31,7 @@ struct symbol *symbol_hash[SYMBOL_HASHSIZE];
 static struct menu *current_menu, *current_entry;
 
 %}
-%expect 32
+%expect 31
 
 %union
 {
@@ -337,7 +337,7 @@ choice_block:
 
 /* if entry */
 
-if_entry: T_IF expr nl
+if_entry: T_IF expr T_EOL
 {
 	printd(DEBUG_PARSE, "%s:%d:if\n", zconf_curname(), zconf_lineno());
 	menu_add_entry(NULL);
@@ -717,6 +717,10 @@ static void print_symbol(FILE *out, struct menu *menu)
 			print_quoted_string(out, prop->text);
 			fputc('\n', out);
 			break;
+		case P_SYMBOL:
+			fputs( "  symbol ", out);
+			fprintf(out, "%s\n", prop->sym->name);
+			break;
 		default:
 			fprintf(out, "  unknown prop %d!\n", prop->type);
 			break;