[v1] LoongArch: Fix relaxation alignment with ld -r (PR 33236)
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Commit Message
LoongArch has the same issue as RISC-V for PR 33236 [1].
Section alignment can't be adjusted for objects generated by ld -r.
If previous sections are relaxed, the subsequent section maybe misaligned.
To fix this, add an align section and an align relocation before each section
when ld -r. And disabling the default section start address calculation.
ld.lld has fixed this issue in the following two patches [2] [3].
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=33236
[2] https://github.com/llvm/llvm-project/pull/151639
[3] https://github.com/llvm/llvm-project/pull/198147
---
bfd/elfnn-loongarch.c | 152 +++++++++++++++
bfd/elfxx-loongarch.h | 10 +
ld/emultempl/loongarchelf.em | 182 ++++++++++++++++++
ld/ldlang.c | 8 +-
.../ld-loongarch-elf/relax-align-ld-r.d | 9 +
.../ld-loongarch-elf/relax-align-ld-r.s | 12 ++
ld/testsuite/ld-loongarch-elf/relax.exp | 4 +
7 files changed, 376 insertions(+), 1 deletion(-)
create mode 100644 ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d
create mode 100644 ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s
Comments
Gentle ping.
在 2026/5/29 15:43, mengqinggang 写道:
> LoongArch has the same issue as RISC-V for PR 33236 [1].
>
> Section alignment can't be adjusted for objects generated by ld -r.
> If previous sections are relaxed, the subsequent section maybe misaligned.
>
> To fix this, add an align section and an align relocation before each section
> when ld -r. And disabling the default section start address calculation.
>
> ld.lld has fixed this issue in the following two patches [2] [3].
>
> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=33236
> [2] https://github.com/llvm/llvm-project/pull/151639
> [3] https://github.com/llvm/llvm-project/pull/198147
> ---
> bfd/elfnn-loongarch.c | 152 +++++++++++++++
> bfd/elfxx-loongarch.h | 10 +
> ld/emultempl/loongarchelf.em | 182 ++++++++++++++++++
> ld/ldlang.c | 8 +-
> .../ld-loongarch-elf/relax-align-ld-r.d | 9 +
> .../ld-loongarch-elf/relax-align-ld-r.s | 12 ++
> ld/testsuite/ld-loongarch-elf/relax.exp | 4 +
> 7 files changed, 376 insertions(+), 1 deletion(-)
> create mode 100644 ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d
> create mode 100644 ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s
>
> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
> index 8f8ec3b0789..ddd321d896f 100644
> --- a/bfd/elfnn-loongarch.c
> +++ b/bfd/elfnn-loongarch.c
> @@ -7067,6 +7067,158 @@ elf_loongarch64_hash_symbol (struct elf_link_hash_entry *h)
> return _bfd_elf_hash_symbol (h);
> }
>
> +/* Write nops to align section. */
> +
> +static bool
> +loongarch_build_align_nops (asection *section, asection *align_section)
> +{
> + if (section->output_section == NULL
> + || align_section->output_section == NULL)
> + {
> + _bfd_error_handler (_("Could not assign to an output section."));
> + return false;
> + }
> +
> + bfd_byte *loc = align_section->contents;
> + for (bfd_size_type i = 0; i < (align_section->size / 4); i++)
> + {
> + bfd_putl32 (LARCH_NOP, loc);
> + loc += 4;
> + }
> +
> + return true;
> +}
> +
> +/* Emit an align relocation and a related undefined symbol. */
> +
> +static bool
> +loongarch_add_align_relocs (asection *sec,
> + asection *align_sec,
> + bfd* align_bfd)
> +{
> + elf_backend_data *bed = get_elf_backend_data (align_bfd);
> +
> + if (elf_section_data (align_sec)->relocs == NULL)
> + {
> + align_sec->reloc_count = 1;
> + align_sec->flags |= SEC_RELOC;
> +
> + Elf_Internal_Rela *rela = (Elf_Internal_Rela *)
> + bfd_malloc (sizeof (Elf_Internal_Rela));
> + if (rela == NULL)
> + return false;
> +
> + rela->r_offset = 0;
> + rela->r_addend = (1 << sec->alignment_power) - 4;
> + rela->r_info = ELFNN_R_INFO (0, R_LARCH_ALIGN);
> + elf_section_data (align_sec)->relocs = rela;
> +
> + Elf_Internal_Shdr *rela_hdr = (Elf_Internal_Shdr *)
> + bfd_zalloc (align_bfd, sizeof (Elf_Internal_Shdr));
> + if (rela_hdr == NULL)
> + return false;
> +
> + rela_hdr->sh_size = sizeof (Elf_Internal_Rela);
> + rela_hdr->sh_entsize = sizeof (Elf_Internal_Rela);
> + rela_hdr->sh_type = SHT_RELA;
> + rela_hdr->sh_addralign = (bfd_vma) 1 << bed->s->log_file_align;
> + elf_section_data (align_sec)->rela.hdr = rela_hdr;
> + }
> +
> + /* Used in loongarch_elf_relax_section for align relocations. */
> + Elf_Internal_Shdr *symtab_hdr = &elf_symtab_hdr (align_bfd);
> + if (symtab_hdr->contents == NULL)
> + {
> + Elf_Internal_Sym *sym = (Elf_Internal_Sym *)
> + bfd_zmalloc (sizeof (Elf_Internal_Sym));
> + if (sym == NULL)
> + return false;
> +
> + /* Match if (r_symndx < symtab_hdr->sh_info) branch in
> + loongarch_elf_relocate_section to avoid find link failed. */
> + symtab_hdr->sh_info = 1;
> +// symtab_hdr->sh_size = sizeof (Elf_Internal_Sym);
> +// symtab_hdr->sh_entsize = sizeof (Elf_Internal_Sym);
> +// symtab_hdr->sh_type = SHT_SYMTAB;
> +// symtab_hdr->sh_addralign = (bfd_vma) 1 << bed->s->log_file_align;
> + symtab_hdr->contents = (unsigned char *) sym;
> + }
> +
> + return true;
> +}
> +
> +/* Section name for aligns is the associated section name plus this
> + string. */
> +#define ALIGN_SUFFIX ".align"
> +
> +/* Determine and set the size of the align section for a final link. */
> +
> +bool
> +elfNN_loongarch_size_aligns (bfd *output_bfd,
> + bfd *align_bfd,
> + struct bfd_link_info *info,
> + asection * (*add_align_section)
> + (const char *, asection *),
> + void (*layout_sections_again) (void))
> +{
> + bool need_laying_out = false;
> + for (bfd *input_bfd = info->input_bfds; input_bfd != NULL;
> + input_bfd = input_bfd->link.next)
> + {
> + asection *sec;
> + asection *align_sec;
> +
> + if (!is_loongarch_elf (input_bfd)
> + || (input_bfd->flags & BFD_LINKER_CREATED) != 0)
> + continue;
> +
> + for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
> + {
> + /* If this section is not a code section, do nothing. */
> + if ((sec->flags & SEC_CODE) == 0)
> + continue;
> +
> + /* If this section is a link-once section that will be
> + discarded, then don't create any stubs. */
> + if (sec->output_section == NULL
> + || sec->output_section->owner != output_bfd)
> + continue;
> +
> + if (sec->alignment_power > 2)
> + {
> + char *s_name;
> + size_t namelen;
> + bfd_size_type len;
> + namelen = strlen (sec->name);
> + len = namelen + sizeof (ALIGN_SUFFIX);
> + s_name = bfd_alloc (align_bfd, len);
> + if (s_name == NULL)
> + return false;
> + memcpy (s_name, sec->name, namelen);
> + memcpy (s_name + namelen, ALIGN_SUFFIX, sizeof (ALIGN_SUFFIX));
> +
> + align_sec = add_align_section (s_name, sec);
> +
> + if (align_sec == NULL)
> + return false;
> +
> + if (! loongarch_build_align_nops (sec, align_sec))
> + return false;
> +
> + if (! loongarch_add_align_relocs (sec, align_sec, align_bfd))
> + return false;
> +
> + need_laying_out = true;
> + }
> + }
> + }
> +
> + if (need_laying_out)
> + layout_sections_again ();
> +
> + return true;
> +}
> +
> #define TARGET_LITTLE_SYM loongarch_elfNN_vec
> #define TARGET_LITTLE_NAME "elfNN-loongarch"
> #define ELF_ARCH bfd_arch_loongarch
> diff --git a/bfd/elfxx-loongarch.h b/bfd/elfxx-loongarch.h
> index 400b7377ccd..b295b7a9070 100644
> --- a/bfd/elfxx-loongarch.h
> +++ b/bfd/elfxx-loongarch.h
> @@ -45,6 +45,16 @@ bfd_elf64_loongarch_set_data_segment_info (struct bfd_link_info *, int *);
> bfd_byte *
> loongarch_write_unsigned_leb128 (bfd_byte *, size_t, bfd_vma) ATTRIBUTE_HIDDEN;
>
> +extern bool elf64_loongarch_size_aligns
> + (bfd *, bfd *, struct bfd_link_info *,
> + struct bfd_section * (*) (const char *, struct bfd_section *),
> + void (*) (void));
> +
> +extern bool elf32_loongarch_size_aligns
> + (bfd *, bfd *, struct bfd_link_info *,
> + struct bfd_section * (*) (const char *, struct bfd_section *),
> + void (*) (void));
> +
> /* TRUE if this is a PLT reference to a local IFUNC. */
> #define PLT_LOCAL_IFUNC_P(INFO, H) \
> ((H)->dynindx == -1 \
> diff --git a/ld/emultempl/loongarchelf.em b/ld/emultempl/loongarchelf.em
> index 5f9d4106629..bbb9c378781 100644
> --- a/ld/emultempl/loongarchelf.em
> +++ b/ld/emultempl/loongarchelf.em
> @@ -41,6 +41,10 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
> '
>
> fragment <<EOF
> +
> +/* Fake input file for align. */
> +static lang_input_statement_type *align_file;
> +
> static void
> larch_elf_before_allocation (void)
> {
> @@ -61,6 +65,136 @@ larch_elf_before_allocation (void)
> link_info.relax_pass = 3;
> }
>
> +/* Traverse the linker tree to insert the align section
> + before input section. */
> +
> +static bool
> +hook_in_align (lang_statement_list_type add,
> + asection *input_section,
> + lang_statement_union_type **lp)
> +{
> + bool ret;
> + lang_statement_union_type *l;
> +
> + for (; (l = *lp) != NULL; lp = &l->header.next)
> + {
> + switch (l->header.type)
> + {
> + case lang_constructors_statement_enum:
> + ret = hook_in_align (add, input_section, &constructor_list.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_output_section_statement_enum:
> + ret = hook_in_align (add, input_section,
> + &l->output_section_statement.children.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_wild_statement_enum:
> + ret = hook_in_align (add, input_section,
> + &l->wild_statement.children.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_group_statement_enum:
> + ret = hook_in_align (add, input_section,
> + &l->group_statement.children.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_input_section_enum:
> + if (l->input_section.section == input_section)
> + {
> + /* We've found our section. Insert the align immediately
> + before its associated input section. */
> + //*(add.tail) = l->header.next;
> + //l->header.next = add.head;
> + *lp = add.head;
> + add.head->header.next = l;
> + return true;
> + }
> + break;
> +
> + case lang_data_statement_enum:
> + case lang_reloc_statement_enum:
> + case lang_object_symbols_statement_enum:
> + case lang_output_statement_enum:
> + case lang_target_statement_enum:
> + case lang_input_statement_enum:
> + case lang_assignment_statement_enum:
> + case lang_padding_statement_enum:
> + case lang_address_statement_enum:
> + case lang_fill_statement_enum:
> + break;
> +
> + default:
> + FAIL ();
> + break;
> + }
> + }
> +
> + return false;
> +}
> +
> +/* Create a new align section, and arrange for it to be linked
> + immediately before INPUT_SECTION. */
> +
> +static asection *
> +elf${ELFSIZE}_loongarch_add_align_section (const char *align_sec_name,
> + asection *input_section)
> +{
> + flagword flags;
> + asection *align_sec;
> + asection *output_section;
> + lang_statement_list_type add_child;
> + lang_output_section_statement_type *os;
> +
> + flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
> + | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
> + align_sec = bfd_make_section_anyway_with_flags (align_file->the_bfd,
> + align_sec_name, flags);
> + if (align_sec == NULL)
> + goto err_ret;
> +
> + align_sec->veneer = 1;
> + bfd_set_section_alignment (align_sec, 2);
> +
> + output_section = input_section->output_section;
> + os = lang_output_section_get (output_section);
> +
> + lang_list_init (&add_child);
> + lang_add_section (&add_child, align_sec, NULL, NULL, os);
> +
> + if (add_child.head == NULL)
> + goto err_ret;
> +
> + align_sec->size = (1 << input_section->alignment_power) - 4;
> + align_sec->contents = bfd_alloc (align_file->the_bfd, align_sec->size);
> + if (align_sec->contents == NULL && align_sec->size != 0)
> + goto err_ret;
> + align_sec->alloced = 1;
> +
> + if (hook_in_align (add_child, input_section, &os->children.head))
> + return align_sec;
> +
> + err_ret:
> + einfo (_("%X%P: can not make align section: %E\n"));
> + return NULL;
> +}
> +
> +static void
> +gldloongarch_layout_sections_again (void)
> +{
> + /* If we have changed sizes of the align sections, then we need
> + to recalculate all the section offsets. */
> + ldelf_map_segments (true);
> +}
> +
> static void
> gld${EMULATION_NAME}_after_allocation (void)
> {
> @@ -78,6 +212,21 @@ gld${EMULATION_NAME}_after_allocation (void)
> }
> }
>
> + /* If generating a relocatable output file, we have to add align
> + at the start of sections. */
> + if (align_file != NULL && bfd_link_relocatable (&link_info))
> + {
> + if (! elf${ELFSIZE}_loongarch_size_aligns (link_info.output_bfd,
> + align_file->the_bfd,
> + &link_info,
> + &elf${ELFSIZE}_loongarch_add_align_section,
> + &gldloongarch_layout_sections_again))
> + {
> + einfo (_("%X%P: can not size align section: %E\n"));
> + return;
> + }
> + }
> +
> /* The program header size of executable file may increase. */
> if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour
> && !bfd_link_relocatable (&link_info))
> @@ -101,7 +250,40 @@ gld${EMULATION_NAME}_after_allocation (void)
> ldelf_map_segments (need_layout);
> }
>
> +/* This is called before the input files are opened. We create a new
> + fake input file to hold the align sections. */
> +
> +static void
> +loongarch_elf_create_output_section_statements (void)
> +{
> + if (! bfd_link_relocatable (&link_info))
> + return;
> +
> + align_file = lang_add_input_file ("linker aligns",
> + lang_input_file_is_fake_enum,
> + NULL);
> + align_file->the_bfd = bfd_create ("linker aligns",
> + link_info.output_bfd);
> + if (align_file->the_bfd == NULL
> + || ! bfd_set_arch_mach (align_file->the_bfd,
> + bfd_get_arch (link_info.output_bfd),
> + bfd_get_mach (link_info.output_bfd)))
> + {
> + fatal (_("%P: can not create BFD: %E\n"));
> + return;
> + }
> +
> + align_file->the_bfd->flags |= BFD_LINKER_CREATED;
> +
> + Elf_Internal_Ehdr *ehdr = elf_elfheader (align_file->the_bfd);
> + elf_backend_data *bed = get_elf_backend_data (link_info.output_bfd);
> + ehdr->e_ident[EI_CLASS] = bed->s->elfclass;
> +
> + ldlang_add_file (align_file);
> +}
> +
> EOF
>
> LDEMUL_BEFORE_ALLOCATION=larch_elf_before_allocation
> LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
> +LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=loongarch_elf_create_output_section_statements
> diff --git a/ld/ldlang.c b/ld/ldlang.c
> index 48dd33a49bb..8c3c287a3a0 100644
> --- a/ld/ldlang.c
> +++ b/ld/ldlang.c
> @@ -5769,6 +5769,10 @@ size_input_section
> {
> bfd_size_type alignment_needed;
>
> + bool synthesize_align = bfd_link_relocatable (&link_info)
> + && (i->flags & SEC_CODE) != 0
> + && bfd_get_arch (i->owner) == bfd_arch_loongarch;
> +
> /* Align this section first to the input sections requirement,
> then to the output section's requirement. If this alignment
> is greater than any seen before, then record it too. Perform
> @@ -5788,7 +5792,9 @@ size_input_section
>
> alignment_needed = align_power (dot, i->alignment_power) - dot;
>
> - if (alignment_needed != 0)
> + /* If synthesized ALIGN may be needed, add one align section
> + and one align relocation and disable the default handling. */
> + if (alignment_needed != 0 && ! synthesize_align)
> {
> insert_pad (this_ptr, fill, TO_SIZE (alignment_needed), o, dot);
> dot += alignment_needed;
> diff --git a/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d
> new file mode 100644
> index 00000000000..a2d19734a59
> --- /dev/null
> +++ b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d
> @@ -0,0 +1,9 @@
> +#as:
> +#ld: -r
> +#objdump: -Dr
> +
> +#...
> +.*R_LARCH_ALIGN.*
> +#...
> +.*R_LARCH_ALIGN.*
> +#...
> diff --git a/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s
> new file mode 100644
> index 00000000000..19555a7148e
> --- /dev/null
> +++ b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s
> @@ -0,0 +1,12 @@
> +# Add an align section before text section when ld -r.
> +# There will be two R_LARCH_ALIGN relocations after ld -r.
> +.text
> + addi.d $a0, $a0, 1
> + call36 func
> + .align 3
> +func:
> + addi.d $a0, $a0, 1
> +
> +# Only add a align section for code section.
> +.data
> + .4byte 0x1234
> diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp b/ld/testsuite/ld-loongarch-elf/relax.exp
> index 7c32a65244c..066f1893042 100644
> --- a/ld/testsuite/ld-loongarch-elf/relax.exp
> +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
> @@ -46,6 +46,10 @@ proc run_partial_linking_align_test {} {
> }
> }
>
> +if [istarget loongarch*-*-*] {
> + run_dump_test "relax-align-ld-r"
> +}
> +
> if [istarget loongarch64-*-*] {
> if [isbuild loongarch64-*-*] {
> run_dump_test "relax-align-ignore-start"
On Fri, 2026-05-29 at 15:43 +0800, mengqinggang wrote:
> + /* Match if (r_symndx < symtab_hdr->sh_info) branch in
> + loongarch_elf_relocate_section to avoid find link failed. */
> + symtab_hdr->sh_info = 1;
> +// symtab_hdr->sh_size = sizeof (Elf_Internal_Sym);
> +// symtab_hdr->sh_entsize = sizeof (Elf_Internal_Sym);
> +// symtab_hdr->sh_type = SHT_SYMTAB;
> +// symtab_hdr->sh_addralign = (bfd_vma) 1 << bed->s->log_file_align;
Hmm, just remove them?
> + symtab_hdr->contents = (unsigned char *) sym;
I'll test if the change will break Linux kernel module this weekend.
On Fri, 2026-06-05 at 17:56 +0800, Xi Ruoyao via Binutils wrote:
> On Fri, 2026-05-29 at 15:43 +0800, mengqinggang wrote:
> > + /* Match if (r_symndx < symtab_hdr->sh_info) branch in
> > + loongarch_elf_relocate_section to avoid find link failed.
> > */
> > + symtab_hdr->sh_info = 1;
> > +// symtab_hdr->sh_size = sizeof (Elf_Internal_Sym);
> > +// symtab_hdr->sh_entsize = sizeof (Elf_Internal_Sym);
> > +// symtab_hdr->sh_type = SHT_SYMTAB;
> > +// symtab_hdr->sh_addralign = (bfd_vma) 1 << bed->s-
> > >log_file_align;
>
> Hmm, just remove them?
>
> > + symtab_hdr->contents = (unsigned char *) sym;
>
> I'll test if the change will break Linux kernel module this weekend.
It does not insert the nops when no inputs have R_LARCH_ALIGN, so kernel
module should be ok.
I've not seriously reviewed all the code change though (well I don't
think I'm really capable to do :).
Hi Alan, this patch modifies |ld/ldlang.c|. Could you please help review
it? Thanks!
在 2026/5/29 15:43, mengqinggang 写道:
> LoongArch has the same issue as RISC-V for PR 33236 [1].
>
> Section alignment can't be adjusted for objects generated by ld -r.
> If previous sections are relaxed, the subsequent section maybe misaligned.
>
> To fix this, add an align section and an align relocation before each section
> when ld -r. And disabling the default section start address calculation.
>
> ld.lld has fixed this issue in the following two patches [2] [3].
>
> [1]https://sourceware.org/bugzilla/show_bug.cgi?id=33236
> [2]https://github.com/llvm/llvm-project/pull/151639
> [3]https://github.com/llvm/llvm-project/pull/198147
> ---
> bfd/elfnn-loongarch.c | 152 +++++++++++++++
> bfd/elfxx-loongarch.h | 10 +
> ld/emultempl/loongarchelf.em | 182 ++++++++++++++++++
> ld/ldlang.c | 8 +-
> .../ld-loongarch-elf/relax-align-ld-r.d | 9 +
> .../ld-loongarch-elf/relax-align-ld-r.s | 12 ++
> ld/testsuite/ld-loongarch-elf/relax.exp | 4 +
> 7 files changed, 376 insertions(+), 1 deletion(-)
> create mode 100644 ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d
> create mode 100644 ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s
>
> diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
> index 8f8ec3b0789..ddd321d896f 100644
> --- a/bfd/elfnn-loongarch.c
> +++ b/bfd/elfnn-loongarch.c
> @@ -7067,6 +7067,158 @@ elf_loongarch64_hash_symbol (struct elf_link_hash_entry *h)
> return _bfd_elf_hash_symbol (h);
> }
>
> +/* Write nops to align section. */
> +
> +static bool
> +loongarch_build_align_nops (asection *section, asection *align_section)
> +{
> + if (section->output_section == NULL
> + || align_section->output_section == NULL)
> + {
> + _bfd_error_handler (_("Could not assign to an output section."));
> + return false;
> + }
> +
> + bfd_byte *loc = align_section->contents;
> + for (bfd_size_type i = 0; i < (align_section->size / 4); i++)
> + {
> + bfd_putl32 (LARCH_NOP, loc);
> + loc += 4;
> + }
> +
> + return true;
> +}
> +
> +/* Emit an align relocation and a related undefined symbol. */
> +
> +static bool
> +loongarch_add_align_relocs (asection *sec,
> + asection *align_sec,
> + bfd* align_bfd)
> +{
> + elf_backend_data *bed = get_elf_backend_data (align_bfd);
> +
> + if (elf_section_data (align_sec)->relocs == NULL)
> + {
> + align_sec->reloc_count = 1;
> + align_sec->flags |= SEC_RELOC;
> +
> + Elf_Internal_Rela *rela = (Elf_Internal_Rela *)
> + bfd_malloc (sizeof (Elf_Internal_Rela));
> + if (rela == NULL)
> + return false;
> +
> + rela->r_offset = 0;
> + rela->r_addend = (1 << sec->alignment_power) - 4;
> + rela->r_info = ELFNN_R_INFO (0, R_LARCH_ALIGN);
> + elf_section_data (align_sec)->relocs = rela;
> +
> + Elf_Internal_Shdr *rela_hdr = (Elf_Internal_Shdr *)
> + bfd_zalloc (align_bfd, sizeof (Elf_Internal_Shdr));
> + if (rela_hdr == NULL)
> + return false;
> +
> + rela_hdr->sh_size = sizeof (Elf_Internal_Rela);
> + rela_hdr->sh_entsize = sizeof (Elf_Internal_Rela);
> + rela_hdr->sh_type = SHT_RELA;
> + rela_hdr->sh_addralign = (bfd_vma) 1 << bed->s->log_file_align;
> + elf_section_data (align_sec)->rela.hdr = rela_hdr;
> + }
> +
> + /* Used in loongarch_elf_relax_section for align relocations. */
> + Elf_Internal_Shdr *symtab_hdr = &elf_symtab_hdr (align_bfd);
> + if (symtab_hdr->contents == NULL)
> + {
> + Elf_Internal_Sym *sym = (Elf_Internal_Sym *)
> + bfd_zmalloc (sizeof (Elf_Internal_Sym));
> + if (sym == NULL)
> + return false;
> +
> + /* Match if (r_symndx < symtab_hdr->sh_info) branch in
> + loongarch_elf_relocate_section to avoid find link failed. */
> + symtab_hdr->sh_info = 1;
> +// symtab_hdr->sh_size = sizeof (Elf_Internal_Sym);
> +// symtab_hdr->sh_entsize = sizeof (Elf_Internal_Sym);
> +// symtab_hdr->sh_type = SHT_SYMTAB;
> +// symtab_hdr->sh_addralign = (bfd_vma) 1 << bed->s->log_file_align;
> + symtab_hdr->contents = (unsigned char *) sym;
> + }
> +
> + return true;
> +}
> +
> +/* Section name for aligns is the associated section name plus this
> + string. */
> +#define ALIGN_SUFFIX ".align"
> +
> +/* Determine and set the size of the align section for a final link. */
> +
> +bool
> +elfNN_loongarch_size_aligns (bfd *output_bfd,
> + bfd *align_bfd,
> + struct bfd_link_info *info,
> + asection * (*add_align_section)
> + (const char *, asection *),
> + void (*layout_sections_again) (void))
> +{
> + bool need_laying_out = false;
> + for (bfd *input_bfd = info->input_bfds; input_bfd != NULL;
> + input_bfd = input_bfd->link.next)
> + {
> + asection *sec;
> + asection *align_sec;
> +
> + if (!is_loongarch_elf (input_bfd)
> + || (input_bfd->flags & BFD_LINKER_CREATED) != 0)
> + continue;
> +
> + for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
> + {
> + /* If this section is not a code section, do nothing. */
> + if ((sec->flags & SEC_CODE) == 0)
> + continue;
> +
> + /* If this section is a link-once section that will be
> + discarded, then don't create any stubs. */
> + if (sec->output_section == NULL
> + || sec->output_section->owner != output_bfd)
> + continue;
> +
> + if (sec->alignment_power > 2)
> + {
> + char *s_name;
> + size_t namelen;
> + bfd_size_type len;
> + namelen = strlen (sec->name);
> + len = namelen + sizeof (ALIGN_SUFFIX);
> + s_name = bfd_alloc (align_bfd, len);
> + if (s_name == NULL)
> + return false;
> + memcpy (s_name, sec->name, namelen);
> + memcpy (s_name + namelen, ALIGN_SUFFIX, sizeof (ALIGN_SUFFIX));
> +
> + align_sec = add_align_section (s_name, sec);
> +
> + if (align_sec == NULL)
> + return false;
> +
> + if (! loongarch_build_align_nops (sec, align_sec))
> + return false;
> +
> + if (! loongarch_add_align_relocs (sec, align_sec, align_bfd))
> + return false;
> +
> + need_laying_out = true;
> + }
> + }
> + }
> +
> + if (need_laying_out)
> + layout_sections_again ();
> +
> + return true;
> +}
> +
> #define TARGET_LITTLE_SYM loongarch_elfNN_vec
> #define TARGET_LITTLE_NAME "elfNN-loongarch"
> #define ELF_ARCH bfd_arch_loongarch
> diff --git a/bfd/elfxx-loongarch.h b/bfd/elfxx-loongarch.h
> index 400b7377ccd..b295b7a9070 100644
> --- a/bfd/elfxx-loongarch.h
> +++ b/bfd/elfxx-loongarch.h
> @@ -45,6 +45,16 @@ bfd_elf64_loongarch_set_data_segment_info (struct bfd_link_info *, int *);
> bfd_byte *
> loongarch_write_unsigned_leb128 (bfd_byte *, size_t, bfd_vma) ATTRIBUTE_HIDDEN;
>
> +extern bool elf64_loongarch_size_aligns
> + (bfd *, bfd *, struct bfd_link_info *,
> + struct bfd_section * (*) (const char *, struct bfd_section *),
> + void (*) (void));
> +
> +extern bool elf32_loongarch_size_aligns
> + (bfd *, bfd *, struct bfd_link_info *,
> + struct bfd_section * (*) (const char *, struct bfd_section *),
> + void (*) (void));
> +
> /* TRUE if this is a PLT reference to a local IFUNC. */
> #define PLT_LOCAL_IFUNC_P(INFO, H) \
> ((H)->dynindx == -1 \
> diff --git a/ld/emultempl/loongarchelf.em b/ld/emultempl/loongarchelf.em
> index 5f9d4106629..bbb9c378781 100644
> --- a/ld/emultempl/loongarchelf.em
> +++ b/ld/emultempl/loongarchelf.em
> @@ -41,6 +41,10 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
> '
>
> fragment <<EOF + +/* Fake input file for align. */ +static
> lang_input_statement_type *align_file; + static void
> larch_elf_before_allocation (void) { @@ -61,6 +65,136 @@
> larch_elf_before_allocation (void) link_info.relax_pass = 3; } +/*
> Traverse the linker tree to insert the align section + before input
> section. */ + +static bool +hook_in_align (lang_statement_list_type
> add, + asection *input_section, + lang_statement_union_type **lp) +{ +
> bool ret; + lang_statement_union_type *l; + + for (; (l = *lp) !=
> NULL; lp = &l->header.next)
> + {
> + switch (l->header.type)
> + {
> + case lang_constructors_statement_enum:
> + ret = hook_in_align (add, input_section, &constructor_list.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_output_section_statement_enum:
> + ret = hook_in_align (add, input_section,
> + &l->output_section_statement.children.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_wild_statement_enum:
> + ret = hook_in_align (add, input_section,
> + &l->wild_statement.children.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_group_statement_enum:
> + ret = hook_in_align (add, input_section,
> + &l->group_statement.children.head);
> + if (ret)
> + return ret;
> + break;
> +
> + case lang_input_section_enum:
> + if (l->input_section.section == input_section)
> + {
> + /* We've found our section. Insert the align immediately
> + before its associated input section. */
> + //*(add.tail) = l->header.next;
> + //l->header.next = add.head;
> + *lp = add.head;
> + add.head->header.next = l;
> + return true;
> + }
> + break;
> +
> + case lang_data_statement_enum:
> + case lang_reloc_statement_enum:
> + case lang_object_symbols_statement_enum:
> + case lang_output_statement_enum:
> + case lang_target_statement_enum:
> + case lang_input_statement_enum:
> + case lang_assignment_statement_enum:
> + case lang_padding_statement_enum:
> + case lang_address_statement_enum:
> + case lang_fill_statement_enum:
> + break;
> +
> + default:
> + FAIL ();
> + break;
> + }
> + }
> +
> + return false;
> +}
> +
> +/* Create a new align section, and arrange for it to be linked
> + immediately before INPUT_SECTION. */
> +
> +static asection *
> +elf${ELFSIZE}_loongarch_add_align_section (const char *align_sec_name,
> + asection *input_section)
> +{
> + flagword flags;
> + asection *align_sec;
> + asection *output_section;
> + lang_statement_list_type add_child;
> + lang_output_section_statement_type *os;
> +
> + flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
> + | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
> + align_sec = bfd_make_section_anyway_with_flags (align_file->the_bfd,
> + align_sec_name, flags);
> + if (align_sec == NULL)
> + goto err_ret;
> +
> + align_sec->veneer = 1;
> + bfd_set_section_alignment (align_sec, 2);
> +
> + output_section = input_section->output_section;
> + os = lang_output_section_get (output_section);
> +
> + lang_list_init (&add_child);
> + lang_add_section (&add_child, align_sec, NULL, NULL, os);
> +
> + if (add_child.head == NULL)
> + goto err_ret;
> +
> + align_sec->size = (1 << input_section->alignment_power) - 4;
> + align_sec->contents = bfd_alloc (align_file->the_bfd, align_sec->size);
> + if (align_sec->contents == NULL && align_sec->size != 0)
> + goto err_ret;
> + align_sec->alloced = 1;
> +
> + if (hook_in_align (add_child, input_section, &os->children.head))
> + return align_sec;
> +
> + err_ret:
> + einfo (_("%X%P: can not make align section: %E\n"));
> + return NULL;
> +}
> +
> +static void
> +gldloongarch_layout_sections_again (void)
> +{
> + /* If we have changed sizes of the align sections, then we need
> + to recalculate all the section offsets. */
> + ldelf_map_segments (true);
> +}
> +
> static void
> gld${EMULATION_NAME}_after_allocation (void)
> {
> @@ -78,6 +212,21 @@ gld${EMULATION_NAME}_after_allocation (void)
> }
> }
>
> + /* If generating a relocatable output file, we have to add align
> + at the start of sections. */
> + if (align_file != NULL && bfd_link_relocatable (&link_info))
> + {
> + if (! elf${ELFSIZE}_loongarch_size_aligns (link_info.output_bfd,
> + align_file->the_bfd,
> + &link_info,
> + &elf${ELFSIZE}_loongarch_add_align_section,
> + &gldloongarch_layout_sections_again))
> + {
> + einfo (_("%X%P: can not size align section: %E\n")); + return; + } + } + /* The program header size of executable file
> may increase. */ if (bfd_get_flavour (link_info.output_bfd) ==
> bfd_target_elf_flavour && !bfd_link_relocatable (&link_info)) @@
> -101,7 +250,40 @@ gld${EMULATION_NAME}_after_allocation (void)
> ldelf_map_segments (need_layout); } +/* This is called before the
> input files are opened. We create a new + fake input file to hold the
> align sections. */ + +static void
> +loongarch_elf_create_output_section_statements (void) +{ + if (!
> bfd_link_relocatable (&link_info)) + return; + + align_file =
> lang_add_input_file ("linker aligns",
> + lang_input_file_is_fake_enum,
> + NULL);
> + align_file->the_bfd = bfd_create ("linker aligns",
> + link_info.output_bfd);
> + if (align_file->the_bfd == NULL
> + || ! bfd_set_arch_mach (align_file->the_bfd,
> + bfd_get_arch (link_info.output_bfd),
> + bfd_get_mach (link_info.output_bfd)))
> + {
> + fatal (_("%P: can not create BFD: %E\n"));
> + return;
> + }
> +
> + align_file->the_bfd->flags |= BFD_LINKER_CREATED;
> +
> + Elf_Internal_Ehdr *ehdr = elf_elfheader (align_file->the_bfd);
> + elf_backend_data *bed = get_elf_backend_data (link_info.output_bfd);
> + ehdr->e_ident[EI_CLASS] = bed->s->elfclass;
> +
> + ldlang_add_file (align_file);
> +}
> +
> EOF
>
> LDEMUL_BEFORE_ALLOCATION=larch_elf_before_allocation
> LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
> +LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=loongarch_elf_create_output_section_statements
> diff --git a/ld/ldlang.c b/ld/ldlang.c
> index 48dd33a49bb..8c3c287a3a0 100644
> --- a/ld/ldlang.c
> +++ b/ld/ldlang.c
> @@ -5769,6 +5769,10 @@ size_input_section
> {
> bfd_size_type alignment_needed;
>
> + bool synthesize_align = bfd_link_relocatable (&link_info)
> + && (i->flags & SEC_CODE) != 0
> + && bfd_get_arch (i->owner) == bfd_arch_loongarch;
> +
> /* Align this section first to the input sections requirement,
> then to the output section's requirement. If this alignment
> is greater than any seen before, then record it too. Perform
> @@ -5788,7 +5792,9 @@ size_input_section
>
> alignment_needed = align_power (dot, i->alignment_power) - dot;
>
> - if (alignment_needed != 0)
> + /* If synthesized ALIGN may be needed, add one align section
> + and one align relocation and disable the default handling. */
> + if (alignment_needed != 0 && ! synthesize_align)
> {
> insert_pad (this_ptr, fill, TO_SIZE (alignment_needed), o, dot);
> dot += alignment_needed;
> diff --git a/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d
> new file mode 100644
> index 00000000000..a2d19734a59
> --- /dev/null
> +++ b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.d
> @@ -0,0 +1,9 @@
> +#as:
> +#ld: -r
> +#objdump: -Dr
> +
> +#...
> +.*R_LARCH_ALIGN.*
> +#...
> +.*R_LARCH_ALIGN.*
> +#...
> diff --git a/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s
> new file mode 100644
> index 00000000000..19555a7148e
> --- /dev/null
> +++ b/ld/testsuite/ld-loongarch-elf/relax-align-ld-r.s
> @@ -0,0 +1,12 @@
> +# Add an align section before text section when ld -r.
> +# There will be two R_LARCH_ALIGN relocations after ld -r.
> +.text
> + addi.d $a0, $a0, 1
> + call36 func
> + .align 3
> +func:
> + addi.d $a0, $a0, 1
> +
> +# Only add a align section for code section.
> +.data
> + .4byte 0x1234
> diff --git a/ld/testsuite/ld-loongarch-elf/relax.exp b/ld/testsuite/ld-loongarch-elf/relax.exp
> index 7c32a65244c..066f1893042 100644
> --- a/ld/testsuite/ld-loongarch-elf/relax.exp
> +++ b/ld/testsuite/ld-loongarch-elf/relax.exp
> @@ -46,6 +46,10 @@ proc run_partial_linking_align_test {} {
> }
> }
>
> +if [istarget loongarch*-*-*] {
> + run_dump_test "relax-align-ld-r"
> +}
> +
> if [istarget loongarch64-*-*] {
> if [isbuild loongarch64-*-*] {
> run_dump_test "relax-align-ignore-start"
On Mon, Jun 08, 2026 at 02:24:01PM +0800, mengqinggang wrote:
> > diff --git a/ld/ldlang.c b/ld/ldlang.c
> > index 48dd33a49bb..8c3c287a3a0 100644
> > --- a/ld/ldlang.c
> > +++ b/ld/ldlang.c
> > @@ -5769,6 +5769,10 @@ size_input_section
> > {
> > bfd_size_type alignment_needed;
> > + bool synthesize_align = bfd_link_relocatable (&link_info)
> > + && (i->flags & SEC_CODE) != 0
> > + && bfd_get_arch (i->owner) == bfd_arch_loongarch;
> > +
> > /* Align this section first to the input sections requirement,
> > then to the output section's requirement. If this alignment
> > is greater than any seen before, then record it too. Perform
> > @@ -5788,7 +5792,9 @@ size_input_section
> > alignment_needed = align_power (dot, i->alignment_power) - dot;
> > - if (alignment_needed != 0)
> > + /* If synthesized ALIGN may be needed, add one align section
> > + and one align relocation and disable the default handling. */
> > + if (alignment_needed != 0 && ! synthesize_align)
> > {
> > insert_pad (this_ptr, fill, TO_SIZE (alignment_needed), o, dot);
> > dot += alignment_needed;
Architecture specific code isn't supposed to be in ldlang.c. Yes, I
know there is a bfd_arch_tic54x test in there. I don't like that one
either.
I haven't looked too deeply into what your patch does, but I think you
should be able to stop ldlang.c:size_input_section padding by changing
the input section alignment_power in add_align_section (and tweak
loongarch_add_align_relocs to not use the sec->alignment_power but
instead align_sec->size).
Thanks for your feedback. I will make changes based on your advice.
在 2026/6/11 06:50, Alan Modra 写道:
> On Mon, Jun 08, 2026 at 02:24:01PM +0800, mengqinggang wrote:
>>> diff --git a/ld/ldlang.c b/ld/ldlang.c
>>> index 48dd33a49bb..8c3c287a3a0 100644
>>> --- a/ld/ldlang.c
>>> +++ b/ld/ldlang.c
>>> @@ -5769,6 +5769,10 @@ size_input_section
>>> {
>>> bfd_size_type alignment_needed;
>>> + bool synthesize_align = bfd_link_relocatable (&link_info)
>>> + && (i->flags & SEC_CODE) != 0
>>> + && bfd_get_arch (i->owner) == bfd_arch_loongarch;
>>> +
>>> /* Align this section first to the input sections requirement,
>>> then to the output section's requirement. If this alignment
>>> is greater than any seen before, then record it too. Perform
>>> @@ -5788,7 +5792,9 @@ size_input_section
>>> alignment_needed = align_power (dot, i->alignment_power) - dot;
>>> - if (alignment_needed != 0)
>>> + /* If synthesized ALIGN may be needed, add one align section
>>> + and one align relocation and disable the default handling. */
>>> + if (alignment_needed != 0 && ! synthesize_align)
>>> {
>>> insert_pad (this_ptr, fill, TO_SIZE (alignment_needed), o, dot);
>>> dot += alignment_needed;
> Architecture specific code isn't supposed to be in ldlang.c. Yes, I
> know there is a bfd_arch_tic54x test in there. I don't like that one
> either.
>
> I haven't looked too deeply into what your patch does, but I think you
> should be able to stop ldlang.c:size_input_section padding by changing
> the input section alignment_power in add_align_section (and tweak
> loongarch_add_align_relocs to not use the sec->alignment_power but
> instead align_sec->size).
>
@@ -7067,6 +7067,158 @@ elf_loongarch64_hash_symbol (struct elf_link_hash_entry *h)
return _bfd_elf_hash_symbol (h);
}
+/* Write nops to align section. */
+
+static bool
+loongarch_build_align_nops (asection *section, asection *align_section)
+{
+ if (section->output_section == NULL
+ || align_section->output_section == NULL)
+ {
+ _bfd_error_handler (_("Could not assign to an output section."));
+ return false;
+ }
+
+ bfd_byte *loc = align_section->contents;
+ for (bfd_size_type i = 0; i < (align_section->size / 4); i++)
+ {
+ bfd_putl32 (LARCH_NOP, loc);
+ loc += 4;
+ }
+
+ return true;
+}
+
+/* Emit an align relocation and a related undefined symbol. */
+
+static bool
+loongarch_add_align_relocs (asection *sec,
+ asection *align_sec,
+ bfd* align_bfd)
+{
+ elf_backend_data *bed = get_elf_backend_data (align_bfd);
+
+ if (elf_section_data (align_sec)->relocs == NULL)
+ {
+ align_sec->reloc_count = 1;
+ align_sec->flags |= SEC_RELOC;
+
+ Elf_Internal_Rela *rela = (Elf_Internal_Rela *)
+ bfd_malloc (sizeof (Elf_Internal_Rela));
+ if (rela == NULL)
+ return false;
+
+ rela->r_offset = 0;
+ rela->r_addend = (1 << sec->alignment_power) - 4;
+ rela->r_info = ELFNN_R_INFO (0, R_LARCH_ALIGN);
+ elf_section_data (align_sec)->relocs = rela;
+
+ Elf_Internal_Shdr *rela_hdr = (Elf_Internal_Shdr *)
+ bfd_zalloc (align_bfd, sizeof (Elf_Internal_Shdr));
+ if (rela_hdr == NULL)
+ return false;
+
+ rela_hdr->sh_size = sizeof (Elf_Internal_Rela);
+ rela_hdr->sh_entsize = sizeof (Elf_Internal_Rela);
+ rela_hdr->sh_type = SHT_RELA;
+ rela_hdr->sh_addralign = (bfd_vma) 1 << bed->s->log_file_align;
+ elf_section_data (align_sec)->rela.hdr = rela_hdr;
+ }
+
+ /* Used in loongarch_elf_relax_section for align relocations. */
+ Elf_Internal_Shdr *symtab_hdr = &elf_symtab_hdr (align_bfd);
+ if (symtab_hdr->contents == NULL)
+ {
+ Elf_Internal_Sym *sym = (Elf_Internal_Sym *)
+ bfd_zmalloc (sizeof (Elf_Internal_Sym));
+ if (sym == NULL)
+ return false;
+
+ /* Match if (r_symndx < symtab_hdr->sh_info) branch in
+ loongarch_elf_relocate_section to avoid find link failed. */
+ symtab_hdr->sh_info = 1;
+// symtab_hdr->sh_size = sizeof (Elf_Internal_Sym);
+// symtab_hdr->sh_entsize = sizeof (Elf_Internal_Sym);
+// symtab_hdr->sh_type = SHT_SYMTAB;
+// symtab_hdr->sh_addralign = (bfd_vma) 1 << bed->s->log_file_align;
+ symtab_hdr->contents = (unsigned char *) sym;
+ }
+
+ return true;
+}
+
+/* Section name for aligns is the associated section name plus this
+ string. */
+#define ALIGN_SUFFIX ".align"
+
+/* Determine and set the size of the align section for a final link. */
+
+bool
+elfNN_loongarch_size_aligns (bfd *output_bfd,
+ bfd *align_bfd,
+ struct bfd_link_info *info,
+ asection * (*add_align_section)
+ (const char *, asection *),
+ void (*layout_sections_again) (void))
+{
+ bool need_laying_out = false;
+ for (bfd *input_bfd = info->input_bfds; input_bfd != NULL;
+ input_bfd = input_bfd->link.next)
+ {
+ asection *sec;
+ asection *align_sec;
+
+ if (!is_loongarch_elf (input_bfd)
+ || (input_bfd->flags & BFD_LINKER_CREATED) != 0)
+ continue;
+
+ for (sec = input_bfd->sections; sec != NULL; sec = sec->next)
+ {
+ /* If this section is not a code section, do nothing. */
+ if ((sec->flags & SEC_CODE) == 0)
+ continue;
+
+ /* If this section is a link-once section that will be
+ discarded, then don't create any stubs. */
+ if (sec->output_section == NULL
+ || sec->output_section->owner != output_bfd)
+ continue;
+
+ if (sec->alignment_power > 2)
+ {
+ char *s_name;
+ size_t namelen;
+ bfd_size_type len;
+ namelen = strlen (sec->name);
+ len = namelen + sizeof (ALIGN_SUFFIX);
+ s_name = bfd_alloc (align_bfd, len);
+ if (s_name == NULL)
+ return false;
+ memcpy (s_name, sec->name, namelen);
+ memcpy (s_name + namelen, ALIGN_SUFFIX, sizeof (ALIGN_SUFFIX));
+
+ align_sec = add_align_section (s_name, sec);
+
+ if (align_sec == NULL)
+ return false;
+
+ if (! loongarch_build_align_nops (sec, align_sec))
+ return false;
+
+ if (! loongarch_add_align_relocs (sec, align_sec, align_bfd))
+ return false;
+
+ need_laying_out = true;
+ }
+ }
+ }
+
+ if (need_laying_out)
+ layout_sections_again ();
+
+ return true;
+}
+
#define TARGET_LITTLE_SYM loongarch_elfNN_vec
#define TARGET_LITTLE_NAME "elfNN-loongarch"
#define ELF_ARCH bfd_arch_loongarch
@@ -45,6 +45,16 @@ bfd_elf64_loongarch_set_data_segment_info (struct bfd_link_info *, int *);
bfd_byte *
loongarch_write_unsigned_leb128 (bfd_byte *, size_t, bfd_vma) ATTRIBUTE_HIDDEN;
+extern bool elf64_loongarch_size_aligns
+ (bfd *, bfd *, struct bfd_link_info *,
+ struct bfd_section * (*) (const char *, struct bfd_section *),
+ void (*) (void));
+
+extern bool elf32_loongarch_size_aligns
+ (bfd *, bfd *, struct bfd_link_info *,
+ struct bfd_section * (*) (const char *, struct bfd_section *),
+ void (*) (void));
+
/* TRUE if this is a PLT reference to a local IFUNC. */
#define PLT_LOCAL_IFUNC_P(INFO, H) \
((H)->dynindx == -1 \
@@ -41,6 +41,10 @@ PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
'
fragment <<EOF
+
+/* Fake input file for align. */
+static lang_input_statement_type *align_file;
+
static void
larch_elf_before_allocation (void)
{
@@ -61,6 +65,136 @@ larch_elf_before_allocation (void)
link_info.relax_pass = 3;
}
+/* Traverse the linker tree to insert the align section
+ before input section. */
+
+static bool
+hook_in_align (lang_statement_list_type add,
+ asection *input_section,
+ lang_statement_union_type **lp)
+{
+ bool ret;
+ lang_statement_union_type *l;
+
+ for (; (l = *lp) != NULL; lp = &l->header.next)
+ {
+ switch (l->header.type)
+ {
+ case lang_constructors_statement_enum:
+ ret = hook_in_align (add, input_section, &constructor_list.head);
+ if (ret)
+ return ret;
+ break;
+
+ case lang_output_section_statement_enum:
+ ret = hook_in_align (add, input_section,
+ &l->output_section_statement.children.head);
+ if (ret)
+ return ret;
+ break;
+
+ case lang_wild_statement_enum:
+ ret = hook_in_align (add, input_section,
+ &l->wild_statement.children.head);
+ if (ret)
+ return ret;
+ break;
+
+ case lang_group_statement_enum:
+ ret = hook_in_align (add, input_section,
+ &l->group_statement.children.head);
+ if (ret)
+ return ret;
+ break;
+
+ case lang_input_section_enum:
+ if (l->input_section.section == input_section)
+ {
+ /* We've found our section. Insert the align immediately
+ before its associated input section. */
+ //*(add.tail) = l->header.next;
+ //l->header.next = add.head;
+ *lp = add.head;
+ add.head->header.next = l;
+ return true;
+ }
+ break;
+
+ case lang_data_statement_enum:
+ case lang_reloc_statement_enum:
+ case lang_object_symbols_statement_enum:
+ case lang_output_statement_enum:
+ case lang_target_statement_enum:
+ case lang_input_statement_enum:
+ case lang_assignment_statement_enum:
+ case lang_padding_statement_enum:
+ case lang_address_statement_enum:
+ case lang_fill_statement_enum:
+ break;
+
+ default:
+ FAIL ();
+ break;
+ }
+ }
+
+ return false;
+}
+
+/* Create a new align section, and arrange for it to be linked
+ immediately before INPUT_SECTION. */
+
+static asection *
+elf${ELFSIZE}_loongarch_add_align_section (const char *align_sec_name,
+ asection *input_section)
+{
+ flagword flags;
+ asection *align_sec;
+ asection *output_section;
+ lang_statement_list_type add_child;
+ lang_output_section_statement_type *os;
+
+ flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
+ | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
+ align_sec = bfd_make_section_anyway_with_flags (align_file->the_bfd,
+ align_sec_name, flags);
+ if (align_sec == NULL)
+ goto err_ret;
+
+ align_sec->veneer = 1;
+ bfd_set_section_alignment (align_sec, 2);
+
+ output_section = input_section->output_section;
+ os = lang_output_section_get (output_section);
+
+ lang_list_init (&add_child);
+ lang_add_section (&add_child, align_sec, NULL, NULL, os);
+
+ if (add_child.head == NULL)
+ goto err_ret;
+
+ align_sec->size = (1 << input_section->alignment_power) - 4;
+ align_sec->contents = bfd_alloc (align_file->the_bfd, align_sec->size);
+ if (align_sec->contents == NULL && align_sec->size != 0)
+ goto err_ret;
+ align_sec->alloced = 1;
+
+ if (hook_in_align (add_child, input_section, &os->children.head))
+ return align_sec;
+
+ err_ret:
+ einfo (_("%X%P: can not make align section: %E\n"));
+ return NULL;
+}
+
+static void
+gldloongarch_layout_sections_again (void)
+{
+ /* If we have changed sizes of the align sections, then we need
+ to recalculate all the section offsets. */
+ ldelf_map_segments (true);
+}
+
static void
gld${EMULATION_NAME}_after_allocation (void)
{
@@ -78,6 +212,21 @@ gld${EMULATION_NAME}_after_allocation (void)
}
}
+ /* If generating a relocatable output file, we have to add align
+ at the start of sections. */
+ if (align_file != NULL && bfd_link_relocatable (&link_info))
+ {
+ if (! elf${ELFSIZE}_loongarch_size_aligns (link_info.output_bfd,
+ align_file->the_bfd,
+ &link_info,
+ &elf${ELFSIZE}_loongarch_add_align_section,
+ &gldloongarch_layout_sections_again))
+ {
+ einfo (_("%X%P: can not size align section: %E\n"));
+ return;
+ }
+ }
+
/* The program header size of executable file may increase. */
if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour
&& !bfd_link_relocatable (&link_info))
@@ -101,7 +250,40 @@ gld${EMULATION_NAME}_after_allocation (void)
ldelf_map_segments (need_layout);
}
+/* This is called before the input files are opened. We create a new
+ fake input file to hold the align sections. */
+
+static void
+loongarch_elf_create_output_section_statements (void)
+{
+ if (! bfd_link_relocatable (&link_info))
+ return;
+
+ align_file = lang_add_input_file ("linker aligns",
+ lang_input_file_is_fake_enum,
+ NULL);
+ align_file->the_bfd = bfd_create ("linker aligns",
+ link_info.output_bfd);
+ if (align_file->the_bfd == NULL
+ || ! bfd_set_arch_mach (align_file->the_bfd,
+ bfd_get_arch (link_info.output_bfd),
+ bfd_get_mach (link_info.output_bfd)))
+ {
+ fatal (_("%P: can not create BFD: %E\n"));
+ return;
+ }
+
+ align_file->the_bfd->flags |= BFD_LINKER_CREATED;
+
+ Elf_Internal_Ehdr *ehdr = elf_elfheader (align_file->the_bfd);
+ elf_backend_data *bed = get_elf_backend_data (link_info.output_bfd);
+ ehdr->e_ident[EI_CLASS] = bed->s->elfclass;
+
+ ldlang_add_file (align_file);
+}
+
EOF
LDEMUL_BEFORE_ALLOCATION=larch_elf_before_allocation
LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
+LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=loongarch_elf_create_output_section_statements
@@ -5769,6 +5769,10 @@ size_input_section
{
bfd_size_type alignment_needed;
+ bool synthesize_align = bfd_link_relocatable (&link_info)
+ && (i->flags & SEC_CODE) != 0
+ && bfd_get_arch (i->owner) == bfd_arch_loongarch;
+
/* Align this section first to the input sections requirement,
then to the output section's requirement. If this alignment
is greater than any seen before, then record it too. Perform
@@ -5788,7 +5792,9 @@ size_input_section
alignment_needed = align_power (dot, i->alignment_power) - dot;
- if (alignment_needed != 0)
+ /* If synthesized ALIGN may be needed, add one align section
+ and one align relocation and disable the default handling. */
+ if (alignment_needed != 0 && ! synthesize_align)
{
insert_pad (this_ptr, fill, TO_SIZE (alignment_needed), o, dot);
dot += alignment_needed;
new file mode 100644
@@ -0,0 +1,9 @@
+#as:
+#ld: -r
+#objdump: -Dr
+
+#...
+.*R_LARCH_ALIGN.*
+#...
+.*R_LARCH_ALIGN.*
+#...
new file mode 100644
@@ -0,0 +1,12 @@
+# Add an align section before text section when ld -r.
+# There will be two R_LARCH_ALIGN relocations after ld -r.
+.text
+ addi.d $a0, $a0, 1
+ call36 func
+ .align 3
+func:
+ addi.d $a0, $a0, 1
+
+# Only add a align section for code section.
+.data
+ .4byte 0x1234
@@ -46,6 +46,10 @@ proc run_partial_linking_align_test {} {
}
}
+if [istarget loongarch*-*-*] {
+ run_dump_test "relax-align-ld-r"
+}
+
if [istarget loongarch64-*-*] {
if [isbuild loongarch64-*-*] {
run_dump_test "relax-align-ignore-start"