[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Tinycc-devel] will touch memory past end of the struct

From: Quentin Carbonneaux
Subject: Re: [Tinycc-devel] will touch memory past end of the struct
Date: Mon, 15 May 2017 16:05:17 +0000
User-agent: Mutt/1.5.23 (2014-03-12)


>From a quick test with tcc, it looks like the
bitfield will be allocated the last 16 bits of
the struct.  When accessing it, tcc generates code
that loads a full 'unsigned int', hence loading
(or writing) 2 bytes after the end of the struct.

Not sure if that answers the question.

By the way, I use bitfields pretty extensively in
my compiler (https://c9x.me/compile/), and it looks
like C99 compound literals are not quite working
yet with those.  For example, the following program
fails to compile:

struct S {
        int x: 2;
        int y: 30;

int f()
        struct S x = {1, 2};
        return (struct S[]){x, {0, 0}}[1].y;



reply via email to

[Prev in Thread] Current Thread [Next in Thread]