[sdcc-devel] [ sdcc-Bugs-1981238 ] Size of structure with zero length bitfield is incorrect

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Bugs item #1981238, was opened at 2008-06-01 12:00
Message generated for change (Comment added) made by bortel
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Laszlo BORTEL (bortel)
Assigned to: Nobody/Anonymous (nobody)
Summary: Size of structure with zero length bitfield is incorrect

Initial Comment:
The following code correctly produces a one-byte-size structure in code memory, because the zero length bitfield p.a occupies no memory. The problem is that sizeof(p) incorrectly reports that the size of the structure is 2 bytes!

code struct {
        char a:0;
        char b;
} p ={1, 2};

int main (void) {
  return sizeof(p);
}

Command to compile:
C:\>sdcc BugReport19.c
C:\>sdcc -v
SDCC : mcs51/gbz80/z80/avr/ds390/pic16/pic14/TININative/xa51/ds400/hc08 2.8.1 #5
187 (May 31 2008) (MINGW32)


(My reason of using the normally useless zero length bitfield is to temporarily "hide" a field for development/debugging purposes, without deleting or commenting out one-by-one all the initialiser values of the structure array.)

----------------------------------------------------------------------

>Comment By: Laszlo BORTEL (bortel)
Date: 2008-06-01 13:59

Message:
Logged In: YES 
user_id=1063737
Originator: YES

Please consider implementing the closely related optimization request "[
1856455 ] zero length bitfield starts new byte allocation" when fixing this
bug.

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