From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw1-x112f.google.com (mail-yw1-x112f.google.com [IPv6:2607:f8b0:4864:20::112f]) by sourceware.org (Postfix) with ESMTPS id CA5523858C39 for ; Fri, 14 Oct 2022 07:24:16 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CA5523858C39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=adacore.com Received: by mail-yw1-x112f.google.com with SMTP id 00721157ae682-357208765adso38303977b3.12 for ; Fri, 14 Oct 2022 00:24:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=adacore.com; s=google; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=Of9t4HMfmQ3iOYIrHcTSH1VenOCwyGEV2oljabQlPvY=; b=jmKBO8pTs/QzHKYB4Zds+FqJ87z8HXDHRCGtpB3ygc0bRFck2nYOGBfon471LyYB0Z XWWXuAJRUMnPKT0LQk5uO0DvzGjYPd99A4+F5niuluW5ZO9egmBezRhwReBVXnLlCa+n ofVWagf9LPpEyea0lMiEJUeNyT+sfKdDlVHJs7njFft1iyXooS18VdPRqEpvzALDz3Gb GODzpkfjSiWRi6uRIFxe4h3mJAYbK3EZgaZdCbAzgAmNCB7p7nPSBjh3PtDh+CVraNJy Cmh74QlePbBEsavAPlrZV711LsTXn7jWZDeMa/1Jf/87WYxPOq6zIb/jiwxvXD4Fe6kS UE3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Of9t4HMfmQ3iOYIrHcTSH1VenOCwyGEV2oljabQlPvY=; b=fKWPZbuEa/mEFsN0KrIcrmP+AFGTB8oaT52QdbdRpVpIbtAAGvQN7jVMNZvQt8iraC ymvAuLvpatga6tBeLw6ZC5bzrythKGh3QlLTlq7xg6mwxRovYXvrm2KR19bssxayCHHk 5dApaL4pNYiEysQqkWsUN+EDBN35iiZ4hVxZXze9xMJyok/uvels57MEEMA0boTNf62w uaMDmhDUZTmCaTULmWBHPqZSFXMYJBrdbMZ8oKEhXyox49SGUppoBUegz0O88Eo12yfa y/rHJfcz2Qhoy3ZwwRmHFBmJUx8Jusw9IqWo+Cj4t1pIILc9ZpWwwZMTCOj2cBAS+5FF w8RQ== X-Gm-Message-State: ACrzQf2iAsH07NkVCOtZ/pey1A71jZ/SFD9fb+OGGh9qpeh7VSEYGGg9 hl6t9zX5NNI1at5PttLgOv/BSUZfVY2tdU2ABlH0VDdwW9ZX3w== X-Google-Smtp-Source: AMsMyM5Tg21fj61jBhawqWuJbkx+yyMOV8xMNqdRSQ6zq6TJxptndDUm4eTvIJl8OmD9vfsjSUH5NDC8gvA8YQd4yF4= X-Received: by 2002:a81:6f88:0:b0:35f:df0e:3a7a with SMTP id k130-20020a816f88000000b0035fdf0e3a7amr3492119ywc.416.1665732256206; Fri, 14 Oct 2022 00:24:16 -0700 (PDT) MIME-Version: 1.0 References: <20221006114628.304185-1-chigot@adacore.com> In-Reply-To: From: =?UTF-8?Q?Cl=C3=A9ment_Chigot?= Date: Fri, 14 Oct 2022 09:24:05 +0200 Message-ID: Subject: Re: [PATCH] RISC-V: fix linker message when relaxation deletes bytes To: Nelson Chu Cc: binutils@sourceware.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-8.5 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Fri, Oct 14, 2022 at 7:08 AM Nelson Chu wrote: > > Hi, > > On Thu, Oct 13, 2022 at 8:06 PM Cl=C3=A9ment Chigot via Binutils > wrote: > > > > Gentle ping > > > > Thanks, > > Cl=C3=A9ment > > > > On Thu, Oct 6, 2022 at 1:46 PM Cl=C3=A9ment Chigot = wrote: > > > > > > The section relaxation can delete some bytes resulting in the symbols= ' > > > value being modified. > > > As the linker messages retrieve a symbol information using the > > > outsymbols field of abfd, it must be updated as well. > > Interesting, I never noticed this. If this is necessary, then other > targets should also update the output symbols when relaxing (nds32 and > sh), but it seems like they don't do that as well. Yeah, I agree there are probably other targets having a similar issue. I don't know at what extend outsymbols is being used for. But the fact that is being filled with "untouched" symbols in object files looks weird to me. Maybe there is something to look into this direction. For now, this patch aims just to fix ld-undefined on Risc-V targets. > > > bfd/ChangeLog: > > > > > > * elfnn-riscv.c (riscv_relax_delete_bytes): Update > > > abfd->outsymbols. > > > > > > ld/ChangeLog: > > > > > > * testsuite/ld-riscv-elf/ld-riscv-elf.exp: New test. > > > * testsuite/ld-riscv-elf/undefined-align.d: New test. > > > * testsuite/ld-riscv-elf/undefined-align.s: New test. > > > --- > > > bfd/elfnn-riscv.c | 23 +++++++++++++++++++= ++ > > > ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp | 1 + > > > ld/testsuite/ld-riscv-elf/undefined-align.d | 5 +++++ > > > ld/testsuite/ld-riscv-elf/undefined-align.s | 10 +++++++++ > > > 4 files changed, 39 insertions(+) > > > create mode 100644 ld/testsuite/ld-riscv-elf/undefined-align.d > > > create mode 100644 ld/testsuite/ld-riscv-elf/undefined-align.s > > > > > > diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c > > > index 3d2ddf4e651..7a6b66dcd8a 100644 > > > --- a/bfd/elfnn-riscv.c > > > +++ b/bfd/elfnn-riscv.c > > > @@ -4060,6 +4060,7 @@ riscv_relax_delete_bytes (bfd *abfd, > > > unsigned int sec_shndx =3D _bfd_elf_section_from_bfd_section (abfd= , sec); > > > struct bfd_elf_section_data *data =3D elf_section_data (sec); > > > bfd_byte *contents =3D data->this_hdr.contents; > > > + asymbol **outsyms =3D bfd_get_outsymbols (abfd); > > > > > > /* Actually delete the bytes. */ > > > sec->size -=3D count; > > > @@ -4158,6 +4159,28 @@ riscv_relax_delete_bytes (bfd *abfd, > > > } > > > } > > > > > > + /* As linker messages are getting symbols through outsymbols field= of abfd, > > > + it must be adjusted too. */ > > > + if (outsyms =3D=3D NULL) > > > + { > > > + if (!bfd_generic_link_read_symbols (abfd)) > > > + link_info->callbacks->einfo (_("%F%P: %pB: could not read sym= bols: %E\n"), abfd); > > > + outsyms =3D bfd_get_outsymbols (abfd); > > > + } > > > + > > > + for (i =3D 0; i < bfd_get_symcount (abfd); i++) > > > + { > > > + asymbol *sym =3D outsyms[i]; > > > + > > > + if (sym->section !=3D sec) > > > + continue; > > > + > > > + /* If the symbol is in the range of memory we just moved, we > > > + have to adjust its value. */ > > > + if (sym->value > addr && sym->value <=3D toaddr) > > > + sym->value -=3D count; > > > + } > > > + > > > return true; > > > } > > > > > > diff --git a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp b/ld/testsuit= e/ld-riscv-elf/ld-riscv-elf.exp > > > index df89e0ee68b..86f1d05bc08 100644 > > > --- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp > > > +++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp > > > @@ -176,6 +176,7 @@ if [istarget "riscv*-*-*"] { > > > [list "Weak reference 64" "-T weakref.ld -m[riscv_choose_lp64= _emul]" "" \ > > > "-march=3Drv64i -mabi=3Dlp64" {weakref64.s} \ > > > {{objdump -d weakref64.d}} "weakref64"]] > > > + run_dump_test "undefined-align" > > > > > > # The following tests require shared library support. > > > if ![check_shared_lib_support] { > > > diff --git a/ld/testsuite/ld-riscv-elf/undefined-align.d b/ld/testsui= te/ld-riscv-elf/undefined-align.d > > > new file mode 100644 > > > index 00000000000..c8cbb84ac7c > > > --- /dev/null > > > +++ b/ld/testsuite/ld-riscv-elf/undefined-align.d > > > @@ -0,0 +1,5 @@ > > > +#name: undefined with alignment > > > +#source: undefined-align.s > > > +#as: > > > +#ld: --relax > > > +#error: \A[^\n]*\.o: in function `_start':\n\(\.text\+0x0\): undefin= ed reference to `foo'\Z > > > diff --git a/ld/testsuite/ld-riscv-elf/undefined-align.s b/ld/testsui= te/ld-riscv-elf/undefined-align.s > > > new file mode 100644 > > > index 00000000000..577557c663a > > > --- /dev/null > > > +++ b/ld/testsuite/ld-riscv-elf/undefined-align.s > > > @@ -0,0 +1,10 @@ > > > +# Make sure that the linker messages take into account the modificat= ion > > > +# of a symbol's value made during the section relaxation. > > > +# Here, "_start" will have an offset made by ".align 4" which will b= e > > > +# removed during the relaxation of R_RISCV_ALIGN. > > > + .text > > > + .align 4 > > > + .globl _start > > > + .type _start, @function > > > +_start: > > > + call foo > > Tested with undefined-align.s, I get the following error message > before applying this patch, > > % riscv64-unknown-elf-ld tmp.o > > riscv64-unknown-elf-ld: tmp.o:(.text+0x0): undefined reference to `foo' > > And get the error after applying this patch, > > % riscv64-unknown-elf-ld tmp.o > > riscv64-unknown-elf-ld: tmp.o: in function `_start': > > (.text+0x0): undefined reference to `foo' > > It reports more detail, but I cannot see if the removed offset may > cause the wrong message? I'm not sure I understand what you mean. As in the object file, _start starts at 0xc, you mean that the error message should be something like: | riscv64-unknown-elf-ld: tmp.o: in function `_start': | (.text+0xc): undefined reference to `foo' ? Thanks, Cl=C3=A9ment