43 lines
1.7 KiB
Diff
43 lines
1.7 KiB
Diff
From 666d0aeb808ac9c10d065ae7b196695c81a25a20 Mon Sep 17 00:00:00 2001
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From: Ariadne Conill <ariadne@dereferenced.org>
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Date: Fri, 21 Aug 2020 06:46:22 +0000
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Subject: [PATCH] Turn on -D_FORTIFY_SOURCE=2 by default for C, C++, ObjC,
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ObjC++, if the optimization level is > 0
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---
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gcc/c-family/c-cppbuiltin.cc | 4 ++++
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gcc/doc/invoke.texi | 6 ++++++
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2 files changed, 10 insertions(+)
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diff --git a/gcc/c-family/c-cppbuiltin.cc b/gcc/c-family/c-cppbuiltin.cc
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index 4672ae8486a..573c021e1e8 100644
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--- a/gcc/c-family/c-cppbuiltin.cc
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+++ b/gcc/c-family/c-cppbuiltin.cc
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@@ -1510,6 +1510,10 @@ c_cpp_builtins (cpp_reader *pfile)
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builtin_define_with_value ("__REGISTER_PREFIX__", REGISTER_PREFIX, 0);
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builtin_define_with_value ("__USER_LABEL_PREFIX__", user_label_prefix, 0);
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+ /* Fortify Source enabled by default for optimization levels > 0 */
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+ if (optimize)
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+ builtin_define_with_int_value ("_FORTIFY_SOURCE", 2);
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+
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/* Misc. */
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if (flag_gnu89_inline)
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cpp_define (pfile, "__GNUC_GNU_INLINE__");
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diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
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index 83bd1bde433..dda299a9987 100644
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--- a/gcc/doc/invoke.texi
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+++ b/gcc/doc/invoke.texi
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@@ -10896,6 +10896,12 @@ also turns on the following optimization flags:
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Please note the warning under @option{-fgcse} about
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invoking @option{-O2} on programs that use computed gotos.
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+NOTE: In Alpine Linux, @option{-D_FORTIFY_SOURCE=2} is
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+set by default, and is activated when @option{-O} is set to 2 or higher.
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+This enables additional compile-time and run-time checks for several libc
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+functions. To disable, specify either @option{-U_FORTIFY_SOURCE} or
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+@option{-D_FORTIFY_SOURCE=0}.
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+
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@item -O3
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@opindex O3
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Optimize yet more. @option{-O3} turns on all optimizations specified
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