Testing macros in clang

test.S

.macro bytereg reg
	.if \reg == %r8 || \reg == %r9 || \reg == %r10 || \reg == %r11 || \reg == %r12 || \reg == %r13 || \reg == %r14 || \reg == %r15
		.set breg, \reg\()b
	.elseif \reg == %rax
		.set breg, %al
	.elseif \reg == %rcx
		.set breg, %cl
	.elseif \reg == %rdx
		.set breg, %dl
	.elseif \reg == %rbx
		.set breg, %bl
	.elseif \reg == rsp
		.set breg, %spl
	.elseif \reg == %rbp
		.set breg, %bpl
	.elseif \reg == rsi
		.set breg, %sil
	.elseif \reg == rdi
		.set breg, %dil
	.else
		.error "Invalid register '\reg\()' while expanding macro 'bytereg\()'"
	.endif
.endm

.macro READ_SMALL_DATA_INPUT	TMP
	bytereg \TMP
	movb	0, breg
.endm

test:
	READ_SMALL_DATA_INPUT %r11



// macOS:
// large - how its assembled in the project
// gcc -DHAVE_CONFIG_H -I.  -Wall -nostdinc -mkernel -fno-builtin-printf -Wframe-larger-than=400 -D__KERNEL__ -D_KERNEL 
// -DKERNEL -DKERNEL_PRIVATE -DDRIVER_PRIVATE -UHAVE_LARGE_STACKS -DNAMEDSTREAMS=1 -D__DARWIN_64_BIT_INO_T=1 -DAPPLE 
// -DNeXT -include ./zfs_config.h -I./include/os/macos/spl -I./include/os/macos/zfs -I./module/icp/include -I./include 
// -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Kernel.framework/Headers 
// -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/System/Library/Frameworks/Kernel.framework/PrivateHeaders 
// -I./module/zstd/include -UDEBUG -DNDEBUG  -I/usr/local/opt/gettext/include -I/usr/local/opt/[email protected]/include  
// -O2 -g -MT module/os/macos/../../icp/asm-x86_64/modes/macos_zfs-isalc_gcm128_sse.o -MD -MP -MF 
// module/os/macos/../../icp/asm-x86_64/modes/.deps/macos_zfs-isalc_gcm128_sse.Tpo -c -o 
// module/os/macos/../../icp/asm-x86_64/modes/macos_zfs-test.o `test -f 'module/os/macos/../../icp/asm-x86_64/modes/test.S' || 
// echo './'`module/os/macos/../../icp/asm-x86_64/modes/test.S
//
// llvm-objdump --disassemble macos_zfs-test.o
./module/icp/asm-x86_64/modes/macos_zfs-test.o: file format Mach-O 64-bit x86-64
Disassembly of section __TEXT,__text:

0000000000000000 test:
       0: 44 8a 1c 25 00 00 00 00       movb    0, %r11b


// Windows:
//
//  clang-cl.exe -DAMD64 -DDBG -DDBG=1 -DDEPRECATE_DDK_FUNCTIONS=1 -DMSC_NOOPT -DWIN64 -DWINNT=1 -DZFS_DEBUG -D_AMD64_
// -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_WARNINGS -D_KERNEL -D_LP64 -D_WIN32_WINNT=0x0601 -D_WIN64 -D__KERNEL__ 
// -D__LP64__ -D__x86_64 -D__x86_64__ -I..\..\..\module\icp\include -I..\..\..\include\os\windows 
// -I..\..\..\include\os\windows\spl -I..\..\..\include\os\windows\zfs -I..\..\..\include 
// -I"C:\Program Files (x86)\Windows Kits\10\Include\10.0.22000.0\shared" 
// -I"C:\Program Files (x86)\Windows Kits\10\Include\10.0.22000.0\km" 
// -I"C:\Program Files (x86)\Windows Kits\10\Include\10.0.22000.0\km\crt" /we4013 /wd4057 /wd4100 /wd4152 /wd4200 
// /wd4201 /wd4211 /wd4204 /wd4210 /wd4389 /wd4706 /wd4131 /wd4115 /wd4018 /wd4206 /wd4324 /wd4053 
// /FI C:/src/openzfs/include/os/windows/zfs/zfs_config.h -m64 -Wno-nonportable-include-path -Wno-unknown-pragmas 
// -Wno-ignored-pragma-intrinsic -Wno-pragma-pack -Wno-microsoft-enum-forward-reference -Wno-visibility 
// -Wno-microsoft-anon-tag -Wno-unused-command-line-argument -Wno-unused-local-typedef -Wno-int-to-void-pointer-cast 
// -Wno-misleading-indentation -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-function -Wno-unused-label 
// -Wno-int-conversion /X /Zp8 /GF /GR- /Gz /kernel /FIwarning.h /FIC:/src/openzfs/out/build/x64-Debug/CMakeFiles/wdkflags.h
// /MTd -o module\icp\CMakeFiles\icpkern.dir\asm-x86_64\modes\test.S.obj -c ..\..\..\module\icp\asm-x86_64\modes\test.S
<unknown>:0: error: expression could not be evaluated
clang -cc1as: fatal error: error in backend: unable to evaluate offset for variable 'breg'