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# DP: Turn on -D_FORTIFY_SOURCE=2 by default for C, C++, ObjC, ObjC++,
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# DP: if the optimization level is > 0
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gcc/doc/invoke.texi | 6 ++++++
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gcc/c-family/c-cppbuiltin.c | 3 +
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2 files changed, 9 insertions(+), 0 deletions(-)
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Index: b/src/gcc/doc/invoke.texi
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===================================================================
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--- a/src/gcc/doc/invoke.texi
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+++ b/src/gcc/doc/invoke.texi
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@@ -6886,6 +6886,12 @@ also turns on the following optimization
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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 Ubuntu 8.10 and later versions, @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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Optimize yet more. @option{-O3} turns on all optimizations specified
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Index: b/src/gcc/c-family/c-cppbuiltin.c
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===================================================================
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--- a/src/gcc/c-family/c-cppbuiltin.c
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+++ b/src/gcc/c-family/c-cppbuiltin.c
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@@ -951,6 +951,10 @@ 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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+ builtin_define_with_int_value ("_FORTIFY_SOURCE", 2);
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if (flag_gnu89_inline)
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cpp_define (pfile, "__GNUC_GNU_INLINE__");