gcc 4.1.1: char *p = "str" puts "str" into rodata

[Denis Vlasenko]

On Sunday 28 January 2007 17:15, Andrew Haley wrote:
> [ off-topic for gcc; redirected to gcc-help ]
> 
> Denis Vlasenko writes:
>  > char p;
>  > int main() {
>  >         p = "";
>  >         return 0;
>  > }
> 
> This is odd code: you're assigning a pointer to a string to a char
> variable.

Sorry, should be "char *p;"
> 
>  > Don't you think that "" should end up in rw data?
> 
> No: it's a literal string.  Many, many years ago, C compilers put
> literal strings into read/write memory and it was possible to alter
> them, but C89 outlawed that practice.

gcc doesn't warn me, it just produces buggy code.

I remember that string literals are special - they decay to "const char *" OR
to "char*" depending on context. In this context, it should decay to "char*",
and it does - gcc doesn't complain "assingment of const to non-const", the bug
is that gcc placed "str" in ro section.

I did get SEGV on this, in busybox project.
--
vda