https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89362
Bug ID: 89362
Summary: [8/9 regression] zlib support breaks libbacktrace on
strict-alignment platforms
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: libbacktrace
Assignee: unassigned at gcc dot gnu.org
Reporter: ebotcazou at gcc dot gnu.org
CC: ian at gcc dot gnu.org
Target Milestone: ---
The new zlib support (PR other/67165) has broken the library on
strict-alignment platforms, for example SPARC64/Linux. Here's a typical ICE
report:
ebotcazou@gcc202:~/build$ gcc/cc1 -quiet pr35318.c -m32 -mcpu=ultrasparc
pr35318.c: In function 'foo':
pr35318.c:9:1: error: unrecognizable insn:
9 | }
| ^
(insn 14 28 29 2 (parallel [
(set (reg:DF 10 %o2 [orig:113 x ] [113])
(asm_operands/v:DF ("") ("=r,r") 0 [
(reg:SI 11 %o3 [orig:113 x+4 ] [113])
(mem/c:DF (plus:SI (reg/f:SI 30 %fp)
(const_int -24 [0xffffffffffffffe8])) [3
%sfp+-24 S8 A64])
]
[
(asm_input:DF ("%0,0") pr35318.c:8)
(asm_input:SI ("m,r") pr35318.c:8)
]
[] pr35318.c:8))
(set (reg:DF 2 %g2 [orig:114 y ] [114])
(asm_operands/v:DF ("") ("=r,r") 1 [
(reg:SI 11 %o3 [orig:113 x+4 ] [113])
(mem/c:DF (plus:SI (reg/f:SI 30 %fp)
(const_int -24 [0xffffffffffffffe8])) [3
%sfp+-24 S8 A64])
]
[
(asm_input:DF ("%0,0") pr35318.c:8)
(asm_input:SI ("m,r") pr35318.c:8)
]
[] pr35318.c:8))
]) "pr35318.c":8:3 -1
(nil))
during RTL pass: reload
during RTL pass: reload
pr35318.c:9:1: internal compiler error: in extract_constrain_insn, at
recog.c:2211
pr35318.c:9:1: internal compiler error: Bus error
Bus error
Program received signal SIGBUS, Bus error.
0x0000010000138ab4 in elf_uncompress_chdr (state=0xfff8000100044000,
compressed=0xfff8000104ca48af "", compressed_size=4074875,
zdebug_table=0xfff800010353e000, error_callback=
0x1000011dfc4 <__sanitizer::(anonymous namespace)::ErrorCallback(void*,
char const*, int)>, data=0x7feffffd5b8, uncompressed=0x7feffffc670,
uncompressed_size=0x7feffffc668)
at
/home/ebotcazou/src/libsanitizer/libbacktrace/../../libbacktrace/elf.c:2580
2580 if (chdr->ch_type != ELFCOMPRESS_ZLIB)
The problem is that most debug sections have alignment 1 so you cannot do:
chdr = (const b_elf_chdr *) compressed;
and expect to have a valid b_elf_chdr on strict-alignment platforms.
This also breaks the sanitizer on these platforms.
