[PATCH v2 3/3] LoongArch: Enable shared library and PIE support for loongarch*-elf

[mengqinggang]

LGTM, thanks!


在 2026/9/9 15:11, mintsuki 写道:
> loongarch*-elf withholds GENERATE_SHLIB_SCRIPT and GENERATE_PIE_SCRIPT,
> so ld refuses -shared and -pie for it.  The exclusion arrived with the
> original LoongArch ld port, copied from the RISC-V emulparams, and no
> reason was recorded for it either.  loongarch*-elf does not set
> EMBEDDED.
>
> The rationale is the one given for the RISC-V patch in this series; it
> applies here unchanged.
>
> ld/
> 	* emulparams/elf32loongarch-defs.sh (GENERATE_SHLIB_SCRIPT): Set
> 	unconditionally rather than only for non-loongarch*-elf targets.
> 	(GENERATE_PIE_SCRIPT): Likewise.
> 	* emulparams/elf64loongarch-defs.sh (GENERATE_SHLIB_SCRIPT):
> 	Likewise.
> 	(GENERATE_PIE_SCRIPT): Likewise.
>
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Mintsuki <mintsuki@protonmail.com>
> ---
>   ld/emulparams/elf32loongarch-defs.sh | 11 ++---------
>   ld/emulparams/elf64loongarch-defs.sh | 11 ++---------
>   2 files changed, 4 insertions(+), 18 deletions(-)
>
> diff --git a/ld/emulparams/elf32loongarch-defs.sh b/ld/emulparams/elf32loongarch-defs.sh
> index f80f5742..05626db0 100644
> --- a/ld/emulparams/elf32loongarch-defs.sh
> +++ b/ld/emulparams/elf32loongarch-defs.sh
> @@ -16,15 +16,8 @@ if test `echo "$host" | sed -e s/64//` = `echo "$target" | sed -e s/64//`; then
>     esac
>   fi
>
> -# Enable shared library support for everything except an embedded elf target.
> -case "$target" in
> -  loongarch*-elf)
> -    ;;
> -  *)
> -    GENERATE_SHLIB_SCRIPT=yes
> -    GENERATE_PIE_SCRIPT=yes
> -    ;;
> -esac
> +GENERATE_SHLIB_SCRIPT=yes
> +GENERATE_PIE_SCRIPT=yes
>
>   IREL_IN_PLT=
>   TEXT_START_ADDR=0x10000
> diff --git a/ld/emulparams/elf64loongarch-defs.sh b/ld/emulparams/elf64loongarch-defs.sh
> index a8147bf7..9b9deabb 100644
> --- a/ld/emulparams/elf64loongarch-defs.sh
> +++ b/ld/emulparams/elf64loongarch-defs.sh
> @@ -16,15 +16,8 @@ if test `echo "$host" | sed -e s/64//` = `echo "$target" | sed -e s/64//`; then
>     esac
>   fi
>
> -# Enable shared library support for everything except an embedded elf target.
> -case "$target" in
> -  loongarch*-elf)
> -    ;;
> -  *)
> -    GENERATE_SHLIB_SCRIPT=yes
> -    GENERATE_PIE_SCRIPT=yes
> -    ;;
> -esac
> +GENERATE_SHLIB_SCRIPT=yes
> +GENERATE_PIE_SCRIPT=yes
>
>   # In all cases, the number is big-endian.
>   # LoongArch nop is 'andi $r0,$r0,0'.
> --
> 2.55.0
>
>
> On Wednesday, September 9th, 2026 at 9:04 AM, mintsuki <mintsuki@protonmail.com> wrote:
>
>> ld refuses both -shared and -pie for riscv*-elf and loongarch*-elf,
>> because their emulparams files withhold GENERATE_SHLIB_SCRIPT and
>> GENERATE_PIE_SCRIPT from those two targets specifically.  This is not
>> the EMBEDDED policy at work -- neither file sets EMBEDDED -- but a pair
>> of one-off "case $target" checks: be1dce26256a for RISC-V, copied into
>> the LoongArch port from it.  Other bare-metal ELF targets generate the
>> scripts; aarch64*-elf was given PIE support on purpose in 3af09e8db308,
>> and f2aaebdb9797, which would have taken it away from EMBEDDED targets
>> generally, was reverted in 8a46e447a88d:
>>
>>    https://inbox.sourceware.org/binutils/20191108103411.GU6708@bubble.grove.modra.org/
>>
>> What this blocks in practice is freestanding relocatable outputs.
>> Those need -pie (or, alternatively, -shared -Bsymbolic), as already
>> supported by x86_64-elf, i686-elf, aarch64-elf, etc...
>> On riscv64-elf and loongarch64-elf compilers accept -fPIE and -fPIC,
>> but the link step using ld.bfd dies with "-pie not supported" or
>> "-shared not supported", so a bare-metal toolchain, that is otherwise
>> complete, cannot build a freestanding relocatable output. A *-linux
>> (or otherwise other hosted) ld.bfd (or LLVM's lld) has to be used
>> for the link step instead.
>>
>> Patch 2 is testsuite preparation.  Three LoongArch DT_RELR tests write
>> out the symbol index of r_info in full, and that index depends on the
>> default hash style: GNU hash requires undefined symbols to precede
>> defined ones in .dynsym, so an undefined weak in those tests sorts to
>> index 2 under the linux default of "both" and to the end of the table
>> under the bare-metal default of sysv.  The relocations themselves are
>> correct either way.  Without that patch, patch 3 turns those three from
>> unsupported into FAIL.
>>
>> Based on 2986ed8ba365 ("Constify targ_desc").  Tested with gcc 16.2.0
>> riscv64-elf and loongarch64-elf toolchains and dejagnu 1.6.3.
>> make check-ld, before and after the series:
>>
>>    riscv64-elf       541 -> 763 passes, 0 unexpected failures either way
>>    loongarch64-elf   540 -> 703 passes, 0 unexpected failures either way
>>
>> No test regresses on either target, and there are no unexpected
>> successes; the increase is the shared and PIE tests that were previously
>> skipped now running.  I have not tested the 32-bit variants, riscv32-elf
>> and loongarch32-elf, which the same emulparams files cover.
>>
>> Mintsuki (3):
>>    RISC-V: Enable shared library and PIE support for riscv*-elf
>>    ld: Pin the hash style in the LoongArch DT_RELR shared tests
>>    LoongArch: Enable shared library and PIE support for loongarch*-elf
>>
>>   ld/emulparams/elf32loongarch-defs.sh                | 11 ++---------
>>   ld/emulparams/elf32lriscv-defs.sh                   | 11 ++---------
>>   ld/emulparams/elf64loongarch-defs.sh                | 11 ++---------
>>   ld/testsuite/ld-loongarch-elf/relr-data-shared.d    |  2 +-
>>   ld/testsuite/ld-loongarch-elf/relr-discard-shared.d |  2 +-
>>   ld/testsuite/ld-loongarch-elf/relr-got-shared.d     |  2 +-
>>   6 files changed, 9 insertions(+), 30 deletions(-)
>>