[LLVMdev] Problem returning structures by value from C

[Lockal]

I have a simple structure in my program:

struct pair { double value; int32_t type; };

Also I have 2 functions, which are called from LLVM code:

extern "C" void dump(pair s) {
    unsigned char *p = reinterpret_cast<unsigned char *>(&s);
    printf("#dump, %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x\n",
      p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11]);
}

extern "C" pair set() {
    pair ret = { 0, 3 };

    unsigned char *p = reinterpret_cast<unsigned char *>(&ret);
    printf("#set, %02x%02x%02x%02x %02x%02x%02x%02x %02x%02x%02x%02x\n",
      p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7], p[8], p[9], p[10], p[11]);

    return ret;
}

LLVM code contains the same structure definition and prototypes for functions:

%0 = type { double, i32 }
declare %0 @set()
declare void @dump(%0)


So the question is: why the structure data is smashed after this code?

%a = call %0 @set()
call void @dump(%0 %a)

Output:
#set, 00000000 00000000 03000000
#dump, 00000000 0000f8ff 88b93709

Is there any way to return structure from C to LLVM by value?