Asking gcc to generate assembler code from your test code I can see that
gcc do not call/malloc any builtin it generates inline code so there is
nothing to free.
-----
.file "check-va.c"
.text
.type passdown, @function
passdown:
.LFB0:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
subq $48, %rsp
movq %rdi, -40(%rbp)
movq %rsi, -48(%rbp)
leaq -32(%rbp), %rax
movq -48(%rbp), %rdx
movq (%rdx), %rcx
movq %rcx, (%rax)
movq 8(%rdx), %rcx
movq %rcx, 8(%rax)
movq 16(%rdx), %rdx
movq %rdx, 16(%rax)
leaq -32(%rbp), %rdx
movq -40(%rbp), %rax
movq %rdx, %rsi
movq %rax, %rdi
call vprintf
movl %eax, -4(%rbp)
movl -4(%rbp), %eax
leave
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE0:
.size passdown, .-passdown
.type myprintf, @function
myprintf:
.LFB1:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
subq $224, %rsp
movq %rsi, -168(%rbp)
movq %rdx, -160(%rbp)
movq %rcx, -152(%rbp)
movq %r8, -144(%rbp)
movq %r9, -136(%rbp)
testb %al, %al
je .L3
movaps %xmm0, -128(%rbp)
movaps %xmm1, -112(%rbp)
movaps %xmm2, -96(%rbp)
movaps %xmm3, -80(%rbp)
movaps %xmm4, -64(%rbp)
movaps %xmm5, -48(%rbp)
movaps %xmm6, -32(%rbp)
movaps %xmm7, -16(%rbp)
.L3:
movq %rdi, -216(%rbp)
movl $8, -200(%rbp)
movl $48, -196(%rbp)
leaq 16(%rbp), %rax
movq %rax, -192(%rbp)
leaq -176(%rbp), %rax
movq %rax, -184(%rbp)
leaq -200(%rbp), %rdx
movq -216(%rbp), %rax
movq %rdx, %rsi
movq %rax, %rdi
call passdown
leave
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE1:
.size myprintf, .-myprintf
.section .rodata
.LC1:
.string "bla"
.LC2:
.string "%s %i %f\n"
.text
.globl main
.type main, @function
main:
.LFB2:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
movsd .LC0(%rip), %xmm0
movl $42, %edx
movl $.LC1, %esi
movl $.LC2, %edi
movl $1, %eax
call myprintf
movl $0, %eax
popq %rbp
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE2:
.size main, .-main
.section .rodata
.align 8
.LC0:
.long 2576980378
.long 1071225241
.ident "GCC: (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3"
.section .note.GNU-stack,"",@progbits
On Sat, Mar 29, 2014 at 9:33 PM, Domingo Alvarez Duarte
<mingo...@gmail.com>wrote:
> Thanks for pointing it and show an example to test !
>
> Now going back to the original problem the original tcc implementation
> leaks memory on:
> ----
> void *__va_copy(struct __va_list_struct *src)
> {
> struct __va_list_struct *dest =
> (struct __va_list_struct *)malloc(sizeof(struct __va_list_struct));
> *dest = *src;
> return dest;
> }
> ----
>
> And I'll continue investigating a way to make it work with fossil-scm for
> the X86_64, the problem that I saw is that there is a double free when the
> process fork somehow the fossil compiled by tcc seem to not duplicate the
> malloced strioneng and both the parent and child free the same string.
>
> Sounds crazy because the os should do that.
>
> Any idea on the memory leak and the process fork ?
>
> Again thanks for you time and attention !
>
>
> On Sat, Mar 29, 2014 at 5:53 PM, Michael Matz <matz....@frakked.de> wrote:
>
>> Hello,
>>
>>
>> On Fri, 28 Mar 2014, Domingo Alvarez Duarte wrote:
>>
>> I found that on X86_64 linux if I do not free the memory on __va_end(),
>>> the
>>> compiled fossil-scm server works, I suspect is something with the
>>> fork/threads.---
>>> void __va_end(struct __va_list_struct *ap)
>>> {
>>> //free(ap);
>>> }
>>>
>>> Cheers !
>>>
>>
>> Errr. I see you now fiddled with that on mob. Commit c025478d7c03,
>> rewriting va* to not use malloc. That's completely wrong. You've
>> effectively changed the ABI of stdarg, and hence interoperability with
>> every non-TCC compiler. The public va_list on x86_64 _must_ be a pointer.
>> To see it breaking try e.g. this:
>>
>> % cat vatest.c
>> #include <stdio.h>
>> #include <stdarg.h>
>>
>> static int passdown (const char *str, va_list ap)
>> {
>> int ret;
>> va_list ap2;
>> va_copy (ap2, ap);
>> ret = vprintf (str, ap2);
>> va_end (ap2);
>> return ret;
>> }
>>
>> static int myprintf (const char *str, ...)
>> {
>> va_list ap;
>> va_start (ap, str);
>> passdown (str, ap);
>> va_end (ap);
>> }
>>
>> int main ()
>> {
>> myprintf ("%s %i %f\n", "bla", 42, 0.4);
>> return 0;
>> }
>>
>> When executed it must print:
>> bla 42 0.400000
>>
>> Before your patch it does, after your patch it prints garbage (on my
>> system " 134514261 0.000000") (without the va_copy and ap2 it even just
>> segfaults now, though strictly speaking that's invalid stdarg usage).
>> Please revert.
>>
>> If you could please _discuss_ changes in parts you don't completely
>> understand on the list before making nilly-willy changes? Just because
>> fossil-scm "works" after your patching doesn't mean much if you don't know
>> _why_ fossil-scm didn't work before, and especially doesn't mean that the
>> change was even correct.
>>
>>
>> Ciao,
>> Michael.
>> _______________________________________________
>> Tinycc-devel mailing list
>> Tinycc-devel@nongnu.org
>> https://lists.nongnu.org/mailman/listinfo/tinycc-devel
>>
>>
>
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