GCC compatibility: Ignore -fstack-clash-protection

[sylvestre.ledru]

Looks good, thanks.

[joerg]

I really don't like ignoring options that are supposed to provide actual functionality. Most of the other options are for pointless fine tuning and workarounds for broken gcc behavior in ancient versions.

[tstellar]

I agree with Joerg, I don't think we should be ignoring these kinds of security flags (even though we already ignore -fstack-check).

include/clang/Driver/Options.td

 defm schedule_insns : BooleanFFlag<"schedule-insns">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm schedule_insns2 : BooleanFFlag<"schedule-insns2">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm see : BooleanFFlag<"see">, Group<clang_ignored_f_Group>;
 defm signaling_nans : BooleanFFlag<"signaling-nans">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm single_precision_constant : BooleanFFlag<"single-precision-constant">,
     Group<clang_ignored_gcc_optimization_f_Group>;
 defm spec_constr_count : BooleanFFlag<"spec-constr-count">, Group<clang_ignored_f_Group>;
 defm stack_check : BooleanFFlag<"stack-check">, Group<clang_ignored_f_Group>;
+defm stack_clash_protection : BooleanFFlag<"stack-clash-protection">, Group<clang_ignored_f_Group>;
 defm strength_reduce :
     BooleanFFlag<"strength-reduce">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm tls_model : BooleanFFlag<"tls-model">, Group<clang_ignored_f_Group>;
 defm tracer : BooleanFFlag<"tracer">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm tree_dce : BooleanFFlag<"tree-dce">, Group<clang_ignored_gcc_optimization_f_Group>;
 defm tree_loop_im : BooleanFFlag<"tree_loop_im">,  Group<clang_ignored_gcc_optimization_f_Group>;
 defm tree_loop_ivcanon : BooleanFFlag<"tree_loop_ivcanon">,  Group<clang_ignored_gcc_optimization_f_Group>;
 defm tree_loop_linear : BooleanFFlag<"tree_loop_linear">,  Group<clang_ignored_gcc_optimization_f_Group>;

test/Driver/clang_f_opts.c

 // RUN:     -fno-caller-saves -fcaller-saves                                  \
 // RUN:     -fno-reorder-blocks -freorder-blocks                              \
 // RUN:     -fno-schedule-insns2 -fschedule-insns2                            \
 // RUN:     -fno-stack-check                                                  \
 // RUN:     -fno-check-new -fcheck-new                                        \
 // RUN:     -ffriend-injection                                                \
 // RUN:     -fno-implement-inlines -fimplement-inlines                        \
 // RUN:     -fstack-check                                                     \
+// RUN:     -fstack-clash-protection                                          \
 // RUN:     -fforce-addr                                                      \
 // RUN:     -malign-functions=100                                             \
 // RUN:     -malign-loops=100                                                 \
 // RUN:     -malign-jumps=100                                                 \
 // RUN:     %s 2>&1 | FileCheck --check-prefix=IGNORE %s
 // IGNORE-NOT: error: unknown argument
 
 // Test that the warning is displayed on these.