How to make Ghidra recognize bit fields?

Question

Suppose we have the following C source:

typedef struct {
  int bit0 : 1;
  int bit1 : 1;
  int bit2 : 1;
  int bit3 : 1;
} bit_struct;

bit_struct a;

void setBit3()
{
  a.bit3 = 1;
}

When we compile it and open the result in Ghidra, the decompilation window shows

void setBit3(void)
{
  a = a | 8;
  return;
}

If we give Ghidra the declaration of bit_struct (using File -> Parse C Source), and then go to the location of a and set its data type to bit_struct, the decompilation changes to

a = (bit_struct)((byte)a | 8);

which still doesn't access bit3 by declared name.

How can we make Ghidra properly decompile it?

Answer 1

Looks like full bitfield support for the decompiler is slated for a future release according to a comment on Ghidra's github issues: Bitfields don't seem to decompile very well #1059