LLVM wrongly brings unused local macros to the final closure

[marcosps]

When trying to extract function gsmld_open from drivers/tty/n_gsm.c on upstream kernel, the final closure brings not used macros from the original file, like:

#define CR                      0x02                                                                                                 
#define EA                      0x01                                                                                                 
#define PF                      0x10                                                                                                 
#define RR                      0x01                                                                                                 
#define UI                      0x03                                                                                                 
#define RNR                     0x05 

it can be checked by the invocation below:

/usr/local/bin/clang-extract -Wp,-MMD,drivers/tty/.n_gsm.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -fmacro-prefix-map=./= -Werror -std=gnu11 -fshort-wchar -funsigned-char -fno-common -fno-PIE -fno-strict-aliasing -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -fcf-protection=branch -fno-jump-tables -m64 -falign-jumps=1 -falign-loops=1 -mno-80387 -mno-fp-ret-in-387 -mpreferred-stack-boundary=3 -mskip-rax-setup -mtune=generic -mno-red-zone -mcmodel=kernel -Wno-sign-compare -fno-asynchronous-unwind-tables -mindirect-branch=thunk-extern -mindirect-branch-register -mindirect-branch-cs-prefix -mfunction-return=thunk-extern -fno-jump-tables -fpatchable-function-entry=16,16 -fno-delete-null-pointer-checks -O2 -fno-allow-store-data-races -fstack-protector-strong -ftrivial-auto-var-init=zero -fno-stack-clash-protection -pg -mrecord-mcount -mfentry -DCC_USING_FENTRY -falign-functions=16 -fstrict-flex-arrays=3 -fno-strict-overflow -fno-stack-check -fconserve-stack -Wall -Wundef -Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type -Werror=strict-prototypes -Wno-format-security -Wno-trigraphs -Wno-frame-address -Wno-address-of-packed-member -Wmissing-declarations -Wmissing-prototypes -Wframe-larger-than=2048 -Wno-main -Wno-unused-but-set-variable -Wno-unused-const-variable -Wno-dangling-pointer -Wvla -Wno-pointer-sign -Wcast-function-type -Wno-stringop-overflow -Wno-array-bounds -Wno-alloc-size-larger-than -Wimplicit-fallthrough=5 -Werror=date-time -Werror=incompatible-pointer-types -Werror=designated-init -Wenum-conversion -Wno-unused-but-set-variable -Wno-unused-const-variable -Wno-restrict -Wno-packed-not-aligned -Wno-format-overflow -Wno-format-truncation -Wno-stringop-truncation -Wno-missing-field-initializers -Wno-type-limits -Wno-shift-negative-value -Wno-maybe-uninitialized -Wno-sign-compare -g -fsanitize=kernel-address -fasan-shadow-offset=0xdffffc0000000000 --param asan-globals=1 --param asan-instrumentation-with-call-threshold=10000 --param asan-instrument-allocas=1 --param asan-stack=1 --param asan-kernel-mem-intrinsic-prefix=1 -DMODULE -DKBUILD_BASENAME="n_gsm" -DKBUILD_MODNAME="n_gsm" -D__KBUILD_MODNAME=kmod_n_gsm -c -o drivers/tty/n_gsm.o drivers/tty/n_gsm.c -DCE_DEBUGINFO_PATH=/home/mpdesouza/git/linux/drivers/tty/n_gsm.ko -DCE_SYMVERS_PATH=/home/mpdesouza/git/linux/Module.symvers -DCE_OUTPUT_FILE=/home/mpdesouza/kgr/livepatches/gsm_check/ce/linux/work_drivers_tty_n_gsm.c/gsm_check_drivers_tty_n_gsm.c -DCE_OUTPUT_FUNCTION_PROTOTYPE_HEADER=/home/mpdesouza/kgr/livepatches/gsm_check/ce/linux/work_drivers_tty_n_gsm.c/proto.h -DCE_DSC_OUTPUT=/home/mpdesouza/kgr/livepatches/gsm_check/ce/linux/work_drivers_tty_n_gsm.c/lp.dsc -DCE_EXTRACT_FUNCTIONS=gsmld_open -DCE_KEEP_INCLUDES -DCE_RENAME_SYMBOLS

Somehow it remove the unused macros, but it seems that LLVM sees them as used.