[Bug ld/17277] New: ld -shared: bogus DT_TEXTREL marker (and R_ARM_NONE) for PC-relative cross-section relocs (e.g. movw/movt)

[roland at gnu dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17277

            Bug ID: 17277
           Summary: ld -shared: bogus DT_TEXTREL marker (and R_ARM_NONE)
                    for PC-relative cross-section relocs (e.g. movw/movt)
           Product: binutils
           Version: 2.24
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ld
          Assignee: unassigned at sourceware dot org
          Reporter: roland at gnu dot org

Reproduced with:

    $ cat pcrel-shared.s
        .syntax unified
        .arm
        .arch armv7-a

        .text
        .globl foo
        .type foo,%function
    foo:    movw r0, #:lower16:symbol - 1f - 8
        movt r0, #:upper16:symbol - 1f - 8
    1:    add r0, pc
        bx lr

    .data
        .globl symbol
        .hidden symbol
    symbol:    .long 22
    $ arm-linux-gnueabi-as -o pcrel-shared.o pcrel-shared.s
    $ arm-linux-gnueabi-ld -shared -o pcrel-shared.so pcrel-shared.o
    $ readelf -dr pcrel-shared.so

    Dynamic section at offset 0x1e4 contains 10 entries:
      Tag        Type                         Name/Value
     0x00000004 (HASH)                       0x94
     0x00000005 (STRTAB)                     0x184
     0x00000006 (SYMTAB)                     0xd4
     0x0000000a (STRSZ)                      63 (bytes)
     0x0000000b (SYMENT)                     16 (bytes)
     0x00000011 (REL)                        0x1c4
     0x00000012 (RELSZ)                      16 (bytes)
     0x00000013 (RELENT)                     8 (bytes)
     0x00000016 (TEXTREL)                    0x0
     0x00000000 (NULL)                       0x0

    Relocation section '.rel.dyn' at offset 0x1c4 contains 2 entries:
     Offset     Info    Type            Sym.Value  Sym. Name
    00000000  00000000 R_ARM_NONE       
    00000000  00000000 R_ARM_NONE       
    $

The R_ARM_NONE relocs are bogus.  More important is the DT_TEXTREL marker,
which is harmfully bogus.

Appears in 2.24 (and earlier) and trunk du jour.  Gold does not have this bug.

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