[...@gnu-6 tmp]$ cat f-1.c
struct line {
int length;
char contents[];
};
void foo (struct line);
struct line
bar ()
{
struct line x;
x.length = sizeof (struct line);
foo (x);
return x;
}
[...@gnu-6 tmp]$ /usr/gcc-4.4/bin/gcc -fno-asynchronous-unwind-tables -O2 -S
f-1.c
[...@gnu-6 tmp]$ cat f-1.s
.file "f-1.c"
.text
.p2align 4,,15
.globl bar
.type bar, @function
bar:
pushq %rbx
movq %rdi, %rbx
subq $32, %rsp
movl $4, (%rdi)
movl $4, (%rsp)
call foo
movl $4, (%rbx)
movq %rbx, %rax
addq $32, %rsp
popq %rbx
ret
.size bar, .-bar
.ident "GCC: (GNU) 4.4.0 20090317 (experimental) [trunk revision
144915]"
.section .note.GNU-stack,"",@progbits
[...@gnu-6 tmp]$ cat f-2.c
struct line {
int length;
struct {} c;
};
void foo (struct line);
struct line
bar ()
{
struct line x;
x.length = sizeof (struct line);
foo (x);
return x;
}
[...@gnu-6 tmp]$ /usr/gcc-4.4/bin/gcc -fno-asynchronous-unwind-tables -O2 -S
f-2.c
[...@gnu-6 tmp]$ cat f-2.s
.file "f-2.c"
.text
.p2align 4,,15
.globl bar
.type bar, @function
bar:
subq $8, %rsp
movl $4, %edi
call foo
movl $4, %eax
addq $8, %rsp
ret
.size bar, .-bar
.ident "GCC: (GNU) 4.4.0 20090317 (experimental) [trunk revision
144915]"
.section .note.GNU-stack,"",@progbits
[...@gnu-6 tmp]$
--
Summary: structures with zero-length array passed/returned
inconsistently
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hjl dot tools at gmail dot com
GCC target triplet: x86_64-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39545
