https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98751
Bug ID: 98751
Summary: libgccjit fails in DWARF 5 handling with
"`.Ldebug_loc2' is already defined" asm error
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: dmalcolm at gcc dot gnu.org
Target Milestone: ---
Most of the jit.exp testsuite is failing, where the tests fail on 3rd
in-process iteration, with asm errors of the form:
symbol `.Ldebug_loc2' is already defined
test-factorial.c.exe iteration 3 of 5: writing reproducer to
./test-factorial.c.exe.reproducer.c
/tmp/libgccjit-7lPSFo/fake.s: Assembler messages:
/tmp/libgccjit-7lPSFo/fake.s:145: Error: symbol `.Ldebug_loc2' is already
defined
./test-factorial.c.exe: error: error invoking gcc driver
FAILED: test-factorial.c.exe iteration 3 of 5: verify_code: result is
NULL
Adding this to set_options in jit.dg/harness.h:
gcc_jit_context_set_bool_option (
ctxt,
GCC_JIT_BOOL_OPTION_KEEP_INTERMEDIATES,
1);
allows the asm to be inspected after the test runs which has:
1st iteration:
138 │ .section .debug_loclists,"",@progbits
139 │ .long .Ldebug_loc3-.Ldebug_loc2
140 │ .Ldebug_loc2:
141 │ .value 0x5
142 │ .byte 0x8
143 │ .byte 0
144 │ .long 0
145 │ .Ldebug_loc0:
146 │ .LLST0:
2nd iteration:
138 │ .section .debug_loclists,"",@progbits
139 │ .long .Ldebug_loc3-.Ldebug_loc2
140 │ .Ldebug_loc2:
141 │ .value 0x5
142 │ .byte 0x8
143 │ .byte 0
144 │ .long 0
145 │ .Ldebug_loc1:
146 │ .LLST0:
3rd iteration:
138 │ .section .debug_loclists,"",@progbits
139 │ .long .Ldebug_loc3-.Ldebug_loc2
140 │ .Ldebug_loc2:
141 │ .value 0x5
142 │ .byte 0x8
143 │ .byte 0
144 │ .long 0
145 │ .Ldebug_loc2:
146 │ .LLST0:
Note how line 145's number increments each time, and on the 3rd iteration is a
duplicate, leading to failure.
The bogus label is being emitted at:
31673 ASM_OUTPUT_LABEL (asm_out_file, loc_section_label);
init_sections_and_labels:
ASM_GENERATE_INTERNAL_LABEL (loc_section_label, DEBUG_LOC_SECTION_LABEL,
generation);
where "generations" is a static local to init_sections_and_labels that
increments, and thus eventually hits the duplicate value.
It looks like generations is meant to be just 0 or 1, but in libgccjit the
compilation code can get repeatedly invoked an arbitrary number of times in
process. If generations is meant to be just 0 or 1, should this value be reset
to 0 at the end of toplev::main ? Doing so is likely to fix this bug.
