https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81361
--- Comment #6 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
It looks like the DW_CFA_set_loc instruction is mishandled in FDEs:
.set L$set$24,LEFDE3-LASFDE3
.long L$set$24 # FDE Length
LASFDE3:
.long LASFDE3-EH_frame1 # FDE CIE offset
.quad LCOLDB1-. # FDE initial location
.set L$set$25,LCOLDE1-LCOLDB1
.quad L$set$25 # FDE address range
.byte 0x8 # uleb128 0x8; Augmentation size
.quad LLSDAC5-. # Language Specific Data Area
.byte 0x1 # DW_CFA_set_loc
.quad LCFI1-.
.byte 0xe # DW_CFA_def_cfa_offset
.byte 0x10 # uleb128 0x10
.byte 0x83 # DW_CFA_offset, column 0x3
.byte 0x2 # uleb128 0x2
yields:
0x00000050: FDE
length: 0x0000002c
CIE_pointer: 0x00000000
start_addr: 0x0000000000000068 ___cold_sect_of___ada_p + 0x0000000a
range_size: 0x000000000000002a (end_addr = 0x0000000000000092)
LSDA address: 0x00000000000000b8
Instructions: 0x0000000000000068: CFA=rsp+8 rip=[rsp]
DW_CFA_set_loc (0xffffffffffffff8e)
DW_CFA_def_cfa_offset (16)
DW_CFA_offset (rbx, -16)
DW_CFA_nop
DW_CFA_nop
0xfffffffffffffff6: CFA=rsp+16 rbx=[rsp] rip=[rsp+8]
so it looks like the PC-relative relocation is not applied to the operand of
the DW_CFA_set_loc, unlike what happens for start_addr and LSDA address.
This DW_CFA_set_loc instruction is emitted by add_cfis_to_fde for the second
FDE generated for the cold part of a function but doesn't seem necessary any
more: the to-be-attached patch yields a clean ACATS on Darwin as well as on
Linux with the -fno-dwarf2-cfi-asm option.
