Hacky LLVM va_arg test

Makefile

CC ?= clang
LLC ?= llc

all:  test

test: va_arg_test
	./va_arg_test

clean:
	rm raw_va_arg.o va_arg_test

raw_va_arg.o: raw_va_arg.ll
	$(LLC) -O0 -filetype=obj -o $@ $<

va_arg_test: va_arg_test.c raw_va_arg.o
	$(CC) -g -O0 -m32 -o $@ $< raw_va_arg.o

raw_va_arg.ll

target triple = "i686-w64-windows-gnu"

define i32 @va_arg_int(i8** %ap) {
    %tmp = va_arg i8** %ap, i32
    ret i32 %tmp
}

define i64 @va_arg_long(i8** %ap) {
    %tmp = va_arg i8** %ap, i64
    ret i64 %tmp
}

va_arg_test.c

#include <stdio.h>
#include <stdarg.h>
#include <assert.h>

extern int va_arg_int(char** ap);
extern long long va_arg_long(char** ap);

long long va_arg_test_c(int argc, ...) {
    va_list ap;
    va_start(ap, argc);
    long long x = va_arg(ap, long long);
    int y = va_arg(ap, int);
    long long z = va_arg(ap, long long);
    return x + (long long)y + z;
}

int va_arg_test_llvm(int argc, ...) {
    va_list ap;
    va_start(ap, argc);
    long long x = va_arg_long(&ap);
    int y = va_arg_int(&ap);
    long long z = va_arg_long(&ap);
    va_end(ap);
    return x + (long long)y + z;
}

int main() {
    assert(va_arg_test_c(3, 0x01LL, 0x02, 0x03LL) == 6);
    assert(va_arg_test_llvm(3, 0x01LL, 0x02, 0x03LL) == 6);
    return 0;
}