patches/gcc/0004-Turn-on-D_FORTIFY_SOURCE-2-by-default-for-C-C-ObjC-O.patch

   1 From 36fde4108ebb872cbf0e45d815e76fc3ef69ded5 Mon Sep 17 00:00:00 2001
   2 From: Ariadne Conill <ariadne@dereferenced.org>
   3 Date: Fri, 21 Aug 2020 06:46:22 +0000
   4 Subject: [PATCH] Turn on -D_FORTIFY_SOURCE=2 by default for C, C++, ObjC,
   5  ObjC++, if the optimization level is > 0
   6
   7 ---
   8  gcc/c-family/c-cppbuiltin.c | 4 ++++
   9  gcc/doc/invoke.texi         | 6 ++++++
  10  2 files changed, 10 insertions(+)
  11
  12 diff --git a/gcc/c-family/c-cppbuiltin.c b/gcc/c-family/c-cppbuiltin.c
  13 index 9f993c4aff2..7db314195ff 100644
  14 --- a/gcc/c-family/c-cppbuiltin.c
  15 +++ b/gcc/c-family/c-cppbuiltin.c
  16 @@ -1421,6 +1421,10 @@ c_cpp_builtins (cpp_reader *pfile)
  17    builtin_define_with_value ("__REGISTER_PREFIX__", REGISTER_PREFIX, 0);
  18    builtin_define_with_value ("__USER_LABEL_PREFIX__", user_label_prefix, 0);
  19
  20 +  /* Fortify Source enabled by default for optimization levels > 0 */
  21 +  if (optimize)
  22 +    builtin_define_with_int_value ("_FORTIFY_SOURCE", 2);
  23 +
  24    /* Misc.  */
  25    if (flag_gnu89_inline)
  26      cpp_define (pfile, "__GNUC_GNU_INLINE__");
  27 diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
  28 index 4b8335bbd1f..833164e0a2b 100644
  29 --- a/gcc/doc/invoke.texi
  30 +++ b/gcc/doc/invoke.texi
  31 @@ -10224,6 +10224,12 @@ also turns on the following optimization flags:
  32  Please note the warning under @option{-fgcse} about
  33  invoking @option{-O2} on programs that use computed gotos.
  34
  35 +NOTE: In Alpine Linux, @option{-D_FORTIFY_SOURCE=2} is
  36 +set by default, and is activated when @option{-O} is set to 2 or higher.
  37 +This enables additional compile-time and run-time checks for several libc
  38 +functions.  To disable, specify either @option{-U_FORTIFY_SOURCE} or
  39 +@option{-D_FORTIFY_SOURCE=0}.
  40 +
  41  @item -O3
  42  @opindex O3
  43  Optimize yet more.  @option{-O3} turns on all optimizations specified
  44 --
  45 2.34.1
  46