[Bug target/104781] New: [12 regression] SEGV in _Unwind_GetGR during i386 Ada bootstrap

["ro at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104781

            Bug ID: 104781
           Summary: [12 regression] SEGV in _Unwind_GetGR during i386 Ada
                    bootstrap
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: hjl at gcc dot gnu.org
  Target Milestone: ---
            Target: i?86-pc-solaris2.11

Between 20220303 (c083e654bd0f29a365ec957c4c0d4e713fb0b010) and
20220304 (49bc9c6c1ef9441c3db586882e1985da3be9cfa1), 32-bit Solaris/x86 Ada
bootstrap got broken: in stage3, I see

xgcc: internal compiler error: Segmentation Fault signal terminated program
gnat1
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
See <https://gcc.gnu.org/bugs/> for instructions.
make[3]: ***
[/vol/gcc/src/hg/master/local/gcc/ada/gcc-interface/Make-lang.in:167:
ada/casing.o] Error 4

 /var/gcc/regression/master/11.4-gcc/build/./prev-gcc/gnat1 -I - -I . -I
ada/generated -I ada -I /vol/gcc/src/hg/master/local/gcc/ada -I ada/libgnat -I
/vol/gcc/src/hg/master/local/gcc/ada/libgnat -I ada/gcc-interface -I
/vol/gcc/src/hg/master/local/gcc/ada/gcc-interface -quiet -nostdinc -O2 -Wextra
-Wall -dumpdir ada/ -dumpbase casing.adb -dumpbase-ext .adb -gnatwa
-fchecking=1 -g -fchecking=1 -gnatpg -gnata -mtune=generic -march=pentium4
-gnatO ada/casing.o /vol/gcc/src/hg/master/local/gcc/ada/casing.adb -o casing.s

Thread 2 received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1 (LWP 1)]
_Unwind_GetGR (regno=5, context=0xfeffc110) at
/vol/gcc/src/hg/master/local/libgcc/unwind-dw2.c:251
251         return * (_Unwind_Ptr *) (_Unwind_Internal_Ptr) val;
(gdb) bt
#0  _Unwind_GetGR (regno=5, context=0xfeffc110) at
/vol/gcc/src/hg/master/local/libgcc/unwind-dw2.c:251
#1  execute_stack_op (op_ptr=0xb0209f9 "\004e\001", op_ptr@entry=0xb0209f7
"ul\004e\001", op_end=op_end@entry=0xb0209f9 "\004e\001",
context=context@entry=0xfeffc110, initial=<optimized out>) at
/vol/gcc/src/hg/master/local/libgcc/unwind-dw2.c:705
#2  0x0abd2fb7 in uw_update_context_1 (context=context@entry=0xfeffc2d0,
fs=fs@entry=0xfeffc1e0) at
/vol/gcc/src/hg/master/local/libgcc/unwind-dw2.c:1483
#3  0x0abd40bd in uw_init_context_1 (context=context@entry=0xfeffc2d0,
outer_cfa=outer_cfa@entry=0xfeffc4b0, outer_ra=<optimized out>) at
/vol/gcc/src/hg/master/local/libgcc/unwind-dw2.c:1613
#4  0x0abd4792 in _Unwind_RaiseException (exc=0xce14220) at
/vol/gcc/src/hg/master/local/libgcc/unwind.inc:93
#5  0x09223417 in ada.exceptions.exception_propagation.propagate_gcc_exception
()
#6  0x09223461 in ada.exceptions.exception_propagation.propagate_exception ()
#7  0x09223874 in ada.exceptions.complete_and_propagate_occurrence ()
#8  0x09223899 in __gnat_raise_exception ()
#9  0x0921ffcf in system.perfect_hash_generators.compute ()
#10 0x08f3fc06 in exp_imgv.build_enumeration_image_tables ()
#11 0x08eb86e6 in exp_ch13.expand_n_freeze_entity ()
#12 0x08f6c2c5 in expander.expand ()
#13 0x0900abc9 in sem.analyze ()
#14 0x0900c011 in sem.insert_list_before_and_analyze ()
#15 0x08f5b39f in exp_util.insert_actions.part ()
#16 0x08f7ee6f in freeze.freeze_expression ()
#17 0x0916ff2b in sem_res.resolve ()
#18 0x09176bc2 in sem_res.resolve_range ()
#19 0x09170b2d in sem_res.resolve ()
#20 0x09090e6d in sem_ch3.process_range_expr_in_decl ()
#21 0x09091ca0 in sem_ch3.set_scalar_range_for_subtype ()
#22 0x0909317d in sem_ch3.process_subtype ()
#23 0x09094947 in sem_ch3.analyze_subtype_declaration ()
#24 0x0900ae9d in sem.analyze ()
#25 0x09084b93 in sem_ch3.analyze_declarations ()
#26 0x090def7b in sem_ch7.analyze_package_specification ()
#27 0x0900b49b in sem.analyze ()
#28 0x090e1a5e in sem_ch7.analyze_package_declaration ()
#29 0x0900adcf in sem.analyze ()
#30 0x09039fa9 in sem_ch10.analyze_compilation_unit ()
#31 0x0900b112 in sem.analyze ()
#32 0x0900c611 in sem.semantics ()
#33 0x0903a31a in sem_ch10.analyze_compilation_unit ()
#34 0x0900b112 in sem.analyze ()
#35 0x0900c611 in sem.semantics ()
#36 0x08f82689 in frontend ()
#37 0x09230fcd in gnat1drv ()
#38 0x08da2142 in gnat_parse_file() ()
#39 0x0980c91d in compile_file() ()
#40 0x0980fe4a in toplev::main(int, char**) ()
#41 0x0a855761 in main ()
(gdb) p val
$1 = (_Unwind_Context_Reg_Val) 0x0

I'm higly suspicious of

commit 609e8c492d62d92465460eae3d43dfc4b2c68288
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Sat Feb 26 14:17:23 2022 -0800

    x86: Always return pseudo register in ix86_gen_scratch_sse_rtx

and am current re-bootstrapping with that patch reverted locally.