[Bug target/103698] New: [12 regression] Code assigned to __attribute__((section(".data"))) generates invalid dwarf: leb128 operand is an undefined symbol

[slyfox at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103698

            Bug ID: 103698
           Summary: [12 regression] Code assigned to
                    __attribute__((section(".data"))) generates invalid
                    dwarf: leb128 operand is an undefined symbol
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---
            Target: arm-none-eabi

Created attachment 51990
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51990&action=edit
bug.c.orig

One-liner extracted from axoloti-1.0.12:

  $ cat bug.c

    __attribute__((section(".data"))) int flash_Erase_sector1(int sector) {}

gcc-10/binutils-2.35 used to somewhat work. gcc-12/binutils-2.37 gets confused
with dwarf data:

$ arm-none-eabi-gcc-10.3.0 -mcpu=cortex-m4 -O2 -ggdb -c bug.c -o bug.o
/tmp/ccMDYjLi.s: Assembler messages:
/tmp/ccMDYjLi.s:15: Warning: ignoring changed section attributes for .data

$ arm-none-eabi-gcc-12.0.0 -mcpu=cortex-m4 -O2 -ggdb -c bug.c -o bug.o
/tmp/ccBo2IfJ.s: Assembler messages:
/tmp/ccBo2IfJ.s:18: Warning: ignoring changed section attributes for .data
/tmp/ccBo2IfJ.s:29: Warning: dwarf line number information for .data ignored
/tmp/ccBo2IfJ.s:34: Warning: dwarf line number information for .data ignored
/tmp/ccBo2IfJ.s:36: Warning: dwarf line number information for .data ignored
/tmp/ccBo2IfJ.s:174: Error: leb128 operand is an undefined symbol: .LVU2
/tmp/ccBo2IfJ.s:175: Error: leb128 operand is an undefined symbol: .LVU2

Also attached bug.c.orig before reduction to get the idea what was original
code's intent.

$ LANG=C ./12/arm-none-eabi-gcc -v
Using built-in specs.
COLLECT_GCC=/nix/store/396wib4x58qxz0i91ggwhwjx1w63rrh4-arm-none-eabi-stage-final-gcc-debug-12.0.0/bin/arm-none-eabi-gcc
COLLECT_LTO_WRAPPER=/nix/store/396wib4x58qxz0i91ggwhwjx1w63rrh4-arm-none-eabi-stage-final-gcc-debug-12.0.0/libexec/gcc/arm-none-eabi/12.0.0/lto-wrapper
Target: arm-none-eabi
Configured with:
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20211212 (experimental) (GCC)

Is it reasonable to expect it to work? Or `.data` is too speacial to expect
code there for dwarf?