On Wed, Mar 12, 2014 at 10:52 PM, Wei Mi <w...@google.com> wrote:
> I saw the problem last patch had on ia32. Without explicit call in rtl
> template, scheduler may schedule the sp adjusting insn across tls
> descriptor and break the alignment assumption.
> I am testing the updated patch on x86_64.
>
> Can we combine the last two patches, both adding call explicitly in
> rtl template for tls_local_dynamic_base_32/tls_global_dynamic_32, and
> set ix86_tls_descriptor_calls_expanded_in_cfun to true only after
> reload complete?
>
My ia32 change generates much worse code:
[hjl@gnu-6 gcc]$ cat /tmp/c.i
static __thread char ccc, bbb;
int __cxa_get_globals()
{
return &ccc - &bbb;
}
[hjl@gnu-6 gcc]$ ./xgcc -B./ -S -O2 -fPIC /tmp/c.i
[hjl@gnu-6 gcc]$ cat c.s
.file "c.i"
.section .text.unlikely,"ax",@progbits
.LCOLDB0:
.text
.LHOTB0:
.p2align 4,,15
.globl __cxa_get_globals
.type __cxa_get_globals, @function
__cxa_get_globals:
.LFB0:
.cfi_startproc
subq $8, %rsp
.cfi_def_cfa_offset 16
leaq ccc@tlsld(%rip), %rdi
call __tls_get_addr@PLT
addq $8, %rsp
.cfi_def_cfa_offset 8
leaq ccc@dtpoff(%rax), %rcx
leaq bbb@dtpoff(%rax), %rdx
movq %rcx, %rax
subq %rdx, %rax
ret
.cfi_endproc
.LFE0:
.size __cxa_get_globals, .-__cxa_get_globals
.section .text.unlikely
.LCOLDE0:
.text
.LHOTE0:
.section .tbss,"awT",@nobits
.type bbb, @object
.size bbb, 1
bbb:
.zero 1
.type ccc, @object
.size ccc, 1
ccc:
.zero 1
.ident "GCC: (GNU) 4.9.0 20140312 (experimental)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-6 gcc]$ cat /tmp/c.i
static __thread char ccc, bbb;
int __cxa_get_globals()
{
return &ccc - &bbb;
}
[hjl@gnu-6 gcc]$ ./xgcc -B./ -S -O2 -fPIC /tmp/c.i -m32
[hjl@gnu-6 gcc]$ cat c.s
.file "c.i"
.section .text.unlikely,"ax",@progbits
.LCOLDB0:
.text
.LHOTB0:
.p2align 4,,15
.globl __cxa_get_globals
.type __cxa_get_globals, @function
__cxa_get_globals:
.LFB0:
.cfi_startproc
pushl %esi
.cfi_def_cfa_offset 8
.cfi_offset 6, -8
pushl %ebx
.cfi_def_cfa_offset 12
.cfi_offset 3, -12
call __x86.get_pc_thunk.bx
addl $_GLOBAL_OFFSET_TABLE_, %ebx
subl $4, %esp
.cfi_def_cfa_offset 16
leal ccc@tlsldm(%ebx), %eax
call ___tls_get_addr@PLT
leal ccc@dtpoff(%eax), %esi
leal ccc@tlsldm(%ebx), %eax
call ___tls_get_addr@PLT
addl $4, %esp
.cfi_def_cfa_offset 12
leal bbb@dtpoff(%eax), %eax
popl %ebx
.cfi_restore 3
.cfi_def_cfa_offset 8
subl %eax, %esi
movl %esi, %eax
popl %esi
.cfi_restore 6
.cfi_def_cfa_offset 4
ret
.cfi_endproc
Maybe we should keep the original patterns and
split them to add CALL.
--
H.J.
