[LLVMdev] Incorrect execution of global constructor with JIT on ARM

[Renato Golin]

On 15 February 2010 14:49, Martins Mozeiko <49640f8a at gmail.com> wrote:
> #include <stdio.h>
> struct Global {
>  typedef unsigned char ArrayType[4];
>  ArrayType value;
>  Global(const ArrayType& arg) {
>    for (int i = 0; i < 4; i++) this->value[i] = arg[i];
>  }
> };
> static const unsigned char arr[] = { 1, 2, 3, 4 };
> static const Global Constant(arr);
> int main() {
>  for (int i=0; i<4; i++) printf("%i", Constant.value[i]);
> }

Compiling with clang I got lots of errors, but boils down to two problems:

>  typedef unsigned char ArrayType[4];

const_array.cpp:3:2: error: type name does not allow storage class to
be specified
 typedef unsigned char ArrayType[4];
 ^

Which, as far as I can tell, it's confusing ArrayType[4] by a
declaration of an unsigned char[4] type.

I've changed your code slightly to make it compile with clang, but I
haven't been able to make it print 4444, not even with your own code,
not even at -O3. There seems to be nothing wrong with the LLVM IR
generated by your code, too, even at -O3.

#include <stdio.h>
typedef unsigned char ArrayType;
struct Global {
 ArrayType value[4];
 Global(const ArrayType* arg) {
   for (int i = 0; i < 4; i++) this->value[i] = arg[i];
 }
};
static const unsigned char arr[] = { 1, 2, 3, 4 };
static const struct Global Constant(arr);
int main() {
 for (int i=0; i<4; i++) printf("%i", Constant.value[i]);
}

See if that helps. I think it has nothing to do with code generation, though.

cheers,
--renato

http://systemcall.org/

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