sizeof computation fails for nested derived types (pointer to array or array of pointers)

[ian-ross]

Bug imported from C2HS Trac

Trac ticket created: 2008-08-01T13:32:18-0700; last modified: 2011-01-19T16:39:31-0800

---

c2hs reports the wrong size of nested derived types.

struct pointer_to_array {
  int (*y)[4  ];
} PTA;
struct array_of_pointers {
  int* y[4];
} AOP;

diff fail2_via_c.out fail2_via_c2hs.out
1,2c1,2
< __tydef__array_of_pointers__: 16
< __tydef__pointer_to_array__: 4

---
> __tydef__array_of_pointers__: 4
> __tydef__pointer_to_array__: 16

The reason for this is that the analysis code assumes that pointer to T is represented as CPointerDeclr TDeclr, but it is actually parsed as TDeclr (...(CPointerDeclr)...).

[ian-ross]

Original comment date: 2011-01-19T16:39:31-0800

---

I think this may be related:
bug.h

typedef char inner_t[32];
typedef struct
{
        inner_t first;
        inner_t second;
} outer_t;

bug.chs

module Bug where
#include "bug.h"
main :: IO ()
main = print ({# sizeof inner_t #}, {# sizeof outer_t #})

Running c2hs bug.chs (on a 64-bit machine) gives me�

module Bug where
main :: IO ()
main = print (32, 16)

Shurely schome mischtake?

On the other hand,
okay.h

typedef struct
{
        char first[32];
        char second[32];
} outer_t;

okay.chs

module Okay where
#include "okay.h"
main :: IO ()
main = print {# sizeof outer_t #}

gives�

module Okay where
main :: IO ()
main = print 64

[ian-ross]

I believe this is now fixed, at least for non-bit-field cases..