Michael Gong wrote:
> Though it's not related with gcc, could anyone help me with following
> question:
>
> Where is the string literal allocated ? Is it on the stack ?
>
> For example, where is "abc" allocated ?
>
> char * foo() {
> return "abc";
> }
Everyone else has already answered your question directly, but I'd like
to point out that the compiler is not a black box -- you can easily see
exactly what it's doing with a few simple commands. Check the docs for
on -S, -save-temps, -fverbose-asm, etc. For example:
$ echo 'char * foo() { return "abc"; }' | gcc -x c - -S -o
-
.file ""
.section .rodata
.LC0:
.string "abc"
.text
.globl foo
.type foo, @function
foo:
pushl %ebp
movl %esp, %ebp
movl $.LC0, %eax
popl %ebp
ret
.size foo, .-foo
.ident "GCC: (GNU) 4.0.4 20060507 (prerelease) (Debian
4.0.3-3)"
.section .note.GNU-stack,"",@progbits
As you can see, it goes in the .rodata section. The above is the
behavior under linux, but for PE (Win32) it is a different section:
$ echo 'char * foo() { return "abc"; }' | gcc -x c - -S -o -
.file ""
.section .rdata,"dr"
LC0:
.ascii "abc\0"
.text
.globl _foo
.def _foo; .scl 2; .type 32; .endef
_foo:
pushl %ebp
movl %esp, %ebp
movl $LC0, %eax
popl %ebp
ret
That is my second point: this kind of thing is platform-dependant
(although it can never be on the stack), and you didn't mention at all
what platform you are using in your original question, which should be a
requirement for almost any compiler/toolchain question.
Brian
