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Add unwind annotations for freebsd/x86 getcontext.S.

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Rearrange the code to put the slow branch out of main body,
and pinch the fixed amount of stack space to be able to annotate
the code.
This commit is contained in:
Konstantin Belousov 2010-05-02 17:06:24 +03:00
parent b73c618a31
commit c84005e9c8
1 changed files with 24 additions and 17 deletions
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41
src/x86/getcontext-freebsd.S
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@ -29,8 +29,10 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
_Ux86_getcontext:
.cfi_startproc
pushl %eax
.cfi_adjust_cfa_offset 4
mov 8(%esp),%eax /* ucontext_t* */
popl FREEBSD_UC_MCONTEXT_EAX_OFF(%eax)
.cfi_adjust_cfa_offset 4
movl %ebx, FREEBSD_UC_MCONTEXT_EBX_OFF(%eax)
movl %ecx, FREEBSD_UC_MCONTEXT_ECX_OFF(%eax)
movl %edx, FREEBSD_UC_MCONTEXT_EDX_OFF(%eax)
@ -59,7 +61,9 @@ _Ux86_getcontext:
movl %ecx, FREEBSD_UC_MCONTEXT_CS_OFF(%eax)
pushfl
.cfi_adjust_cfa_offset 4
popl FREEBSD_UC_MCONTEXT_EFLAGS_OFF(%eax)
.cfi_adjust_cfa_offset -4
movl $0, FREEBSD_UC_MCONTEXT_TRAPNO_OFF(%eax)
@ -77,27 +81,30 @@ _Ux86_getcontext:
*/
leal FREEBSD_UC_MCONTEXT_FPSTATE_OFF(%eax), %edx
testl $0xf, %edx
je 1f
movl %edx, %edi
movl %esp, %edx
subl $512, %esp
andl $~0xf, %esp
fxsave (%esp)
movl %esp, %esi
movl $512/4,%ecx
rep; movsl
movl %edx, %esp
movl FREEBSD_UC_MCONTEXT_ESI_OFF(%eax), %esi
movl FREEBSD_UC_MCONTEXT_EDI_OFF(%eax), %edi
jmp 2f
1: fxsave (%edx)
2:
movl $FREEBSD_UC_MCONTEXT_MC_LEN_VAL,\
jne 2f
fxsave (%edx) /* fast path, passed ucontext save area was aligned */
1: movl $FREEBSD_UC_MCONTEXT_MC_LEN_VAL,\
FREEBSD_UC_MCONTEXT_MC_LEN_OFF(%eax)
xorl %eax, %eax
ret
2: movl %edx, %edi /* not aligned, do the dance */
subl $512 + 16, %esp /* save area and 16 bytes for alignment */
.cfi_adjust_cfa_offset 512 + 16
movl %esp, %edx
orl $0xf, %edx /* align *%edx to 16-byte up */
incl %edx
fxsave (%edx)
movl %edx, %esi /* copy to the final destination */
movl $512/4,%ecx
rep; movsl
addl $512 + 16, %esp /* restore the stack */
.cfi_adjust_cfa_offset -512 - 16
movl FREEBSD_UC_MCONTEXT_ESI_OFF(%eax), %esi
movl FREEBSD_UC_MCONTEXT_EDI_OFF(%eax), %edi
jmp 1b
.cfi_endproc
.size _Ux86_getcontext, . - _Ux86_getcontext