[hjl@gnu-cfl-1 tmp]$ cat x.cc
extern void foo (void);
int
func ()
{
try {
foo ();
}
catch (int x) {
return (x != 5);
}
return 1;
}
[hjl@gnu-cfl-1 tmp]$ clang -fexceptions -fcf-protection -O2 -S x.cc -o llvm.s
[hjl@gnu-cfl-1 tmp]$ cat llvm.s
.text
.section .note.gnu.property,"a",@note
.p2align 3
.long 4
.long 16
.long 5
.asciz "GNU"
.long 3221225474
.long 4
.long 3
.p2align 3
.Lsec_end0:
.text
.file "x.cc"
.globl _Z4funcv # -- Begin function _Z4funcv
.p2align 4, 0x90
.type _Z4funcv,@function
_Z4funcv: # @_Z4funcv
.Lfunc_begin0:
.cfi_startproc
.cfi_personality 3, __gxx_personality_v0
.cfi_lsda 3, .Lexception0
# %bb.0:
endbr64
pushq %rbx
.cfi_def_cfa_offset 16
.cfi_offset %rbx, -16
movl $1, %ebx
.Ltmp0:
callq _Z3foov
.Ltmp1:
.LBB0_2:
movl %ebx, %eax
popq %rbx
.cfi_def_cfa_offset 8
retq
.LBB0_1:
.cfi_def_cfa_offset 16
.Ltmp2:
movq %rax, %rdi
callq __cxa_begin_catch
xorl %ebx, %ebx
cmpl $5, (%rax)
setne %bl
callq __cxa_end_catch
jmp .LBB0_2
.Lfunc_end0:
.size _Z4funcv, .Lfunc_end0-_Z4funcv
.cfi_endproc
.section .gcc_except_table,"a",@progbits
.p2align 2
GCC_except_table0:
.Lexception0:
.byte 255 # @LPStart Encoding = omit
.byte 3 # @TType Encoding = udata4
.uleb128 .Lttbase0-.Lttbaseref0
.Lttbaseref0:
.byte 1 # Call site Encoding = uleb128
.uleb128 .Lcst_end0-.Lcst_begin0
.Lcst_begin0:
.uleb128 .Ltmp0-.Lfunc_begin0 # >> Call Site 1 <<
.uleb128 .Ltmp1-.Ltmp0 # Call between .Ltmp0 and .Ltmp1
.uleb128 .Ltmp2-.Lfunc_begin0 # jumps to .Ltmp2
.byte 1 # On action: 1
.uleb128 .Ltmp1-.Lfunc_begin0 # >> Call Site 2 <<
.uleb128 .Lfunc_end0-.Ltmp1 # Call between .Ltmp1 and .Lfunc_end0
.byte 0 # has no landing pad
.byte 0 # On action: cleanup
.Lcst_end0:
.byte 1 # >> Action Record 1 <<
# Catch TypeInfo 1
.byte 0 # No further actions
.p2align 2
# >> Catch TypeInfos <<
.long _ZTIi # TypeInfo 1
.Lttbase0:
.p2align 2
# -- End function
.ident "clang version 9.0.1 (Fedora 9.0.1-2.fc31)"
.section ".note.GNU-stack","",@progbits
.addrsig
.addrsig_sym __gxx_personality_v0
.addrsig_sym _ZTIi
There is no ENDBR at exception landing pad, which may be reached
via indirect branch, and program will crash on CET enabled machine.
[hjl@gnu-cfl-1 tmp]$ gcc -fexceptions -fcf-protection -O2 -S x.cc -o gcc.s
[hjl@gnu-cfl-1 tmp]$ cat gcc.s
.file "x.cc"
.text
.section .text.unlikely,"ax",@progbits
.LCOLDB0:
.text
.LHOTB0:
.p2align 4
.globl _Z4funcv
.type _Z4funcv, @function
_Z4funcv:
.LFB0:
.cfi_startproc
.cfi_personality 0x3,__gxx_personality_v0
.cfi_lsda 0x3,.LLSDA0
endbr64
subq $24, %rsp
.cfi_def_cfa_offset 32
.LEHB0:
call _Z3foov
.LEHE0:
movl $1, %eax
.L1:
addq $24, %rsp
.cfi_remember_state
.cfi_def_cfa_offset 8
ret
.L5:
.cfi_restore_state
endbr64 <<<<<<<<< ENDBR
movq %rax, %rdi
movq %rdx, %rax
jmp .L2
.globl __gxx_personality_v0
.section .gcc_except_table,"a",@progbits
.align 4
.LLSDA0:
.byte 0xff
.byte 0x3
.uleb128 .LLSDATT0-.LLSDATTD0
.LLSDATTD0:
.byte 0x1
.uleb128 .LLSDACSE0-.LLSDACSB0
.LLSDACSB0:
.uleb128 .LEHB0-.LFB0
.uleb128 .LEHE0-.LEHB0
.uleb128 .L5-.LFB0
.uleb128 0x1
.LLSDACSE0:
.byte 0x1
.byte 0
.align 4
.long _ZTIi
.LLSDATT0:
.text
.cfi_endproc
.section .text.unlikely
.cfi_startproc
.cfi_personality 0x3,__gxx_personality_v0
.cfi_lsda 0x3,.LLSDAC0
.type _Z4funcv.cold, @function
_Z4funcv.cold:
.LFSB0:
.L2:
.cfi_def_cfa_offset 32
subq $1, %rax
jne .L8
call __cxa_begin_catch
cmpl $5, (%rax)
setne %al
movzbl %al, %eax
movl %eax, 12(%rsp)
call __cxa_end_catch
movl 12(%rsp), %eax
jmp .L1
.L8:
.LEHB1:
call _Unwind_Resume
.LEHE1:
.cfi_endproc
.LFE0:
.section .gcc_except_table
.align 4
.LLSDAC0:
.byte 0xff
.byte 0x3
.uleb128 .LLSDATTC0-.LLSDATTDC0
.LLSDATTDC0:
.byte 0x1
.uleb128 .LLSDACSEC0-.LLSDACSBC0
.LLSDACSBC0:
.uleb128 .LEHB1-.LCOLDB0
.uleb128 .LEHE1-.LEHB1
.uleb128 0
.uleb128 0
.LLSDACSEC0:
.byte 0x1
.byte 0
.align 4
.long _ZTIi
.LLSDATTC0:
.section .text.unlikely
.text
.size _Z4funcv, .-_Z4funcv
.section .text.unlikely
.size _Z4funcv.cold, .-_Z4funcv.cold
.LCOLDE0:
.text
.LHOTE0:
.ident "GCC: (GNU) 9.2.1 20200123 (Red Hat 9.2.1-3)"
.section .note.GNU-stack,"",@progbits
.section .note.gnu.property,"a"
.align 8
.long 1f - 0f
.long 4f - 1f
.long 5
0:
.string "GNU"
1:
.align 8
.long 0xc0000002
.long 3f - 2f
2:
.long 0x3
3:
.align 8
4:
[hjl@gnu-cfl-1 tmp]$
