Why does IDA Pro's pseudocode function not produce for loops?

Question

Question came up in a reverse engineering class. The prof asked this question. I mean, in the grand scheme of things, while loops == for loops, I don't have a problem with that.

IDA Pro book... Google... not seeing anything online here.

So why does IDA pro never produce for loops in its pseudocode generator?

Answer 1

Just because you haven't seem them does not mean they don't exist. In my experience the decompiler produces for loops all the time.

EDIT: Here's just one example:

 loc_804B520:
                 xor     edx, edx
                 jmp     short loc_804B52B

 loc_804B524:
                 mov     al, [edi+edx]
                 mov     [ebx+edx], al
                 inc     edx

 loc_804B52B:
                 cmp     edx, esi
                 jl      short loc_804B524

Output:

  for ( i = 0; i < a2; ++i )
    *(_BYTE *)(v2 + i) = *(_BYTE *)(a1 + i);

Answer 2

The decompiler can produce for loops.

It uses the Ctree statement element cit_for and the Ctree expression cfor_t to represent these code constructs in the decompilation graph.