[Bug target/123846] New: mips(el): incorrect symbol .size emitted for struct containing VLA

[equinox-gccbugs at diac24 dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123846

            Bug ID: 123846
           Summary: mips(el): incorrect symbol .size emitted for struct
                    containing VLA
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: equinox-gccbugs at diac24 dot net
  Target Milestone: ---

mipsel-*-gcc emits an incorrect symbol size for a struct with a VLA at the end
with initializers.  Minimal testcase:

/******/
struct foo {
        int a;
        int b[];
} foovar = {
        .a = 1,
        .b = { 2, 3, 4, },
};
/******/

Assembling with mipsel-linux-gnu-gcc (Gentoo build of current HEAD ==
54c716b6fce2) results in:

/******/
        .file   1 "tc.c"
        .section .mdebug.abi32
        .previous
        .nan    legacy
        .module fp=32
        .module nooddspreg
        .module arch=mips1
        .abicalls
        .text
        .globl  foovar
        .data
        .align  2
        .type   foovar, @object
        .size   foovar, 4
foovar:
        .word   1
        .word   2
        .word   3
        .word   4
        .ident  "GCC: (Gentoo Hardened 16.0.9999 p, commit
54c716b6fce290b84871acc99da8dd8d28392069) 16.0.1 20260127 (experimental)
fe050fa9d1249a7a528a30a499d1abc23f47f2c8"
        .section        .note.GNU-stack,"",@progbits
/******/

meanwhile the other architectures I had at hand compile it correctly:

$ grep size *.S
aarch64-linux-gnu-tc.S: .size   foovar, 16
arm-linux-gnueabihf-tc.S:       .size   foovar, 16
mipsel-linux-gnu-tc.S:  .size   foovar, 4
powerpc64-linux-gnu-tc.S:       .size   foovar, 16
powerpc-linux-gnu-tc.S: .size   foovar, 16
x86_64-pc-linux-gnu-tc.S:       .size   foovar, 16

Note the data itself is actually output even on mipsel, so it works "most of
the time". But with a shared library, the incorrect size results in crashes
when the linker creates a copy relocation for such a symbol, truncating it in
the process.