[PATCH] LoongArch: Fix the issue of excessive relocation generated by IE
Lulu Cai
cailulu@loongson.cn
Sun Feb 4 03:18:19 GMT 2024
Currently, whether GD and IE generate dynamic repositioning is
determined by SYMBOL_REFERENCES_LOCAL and bfd_link_executable.
This results in dynamic relocations still being generated in some
situations where dynamic relocations are not necessary (such as
the undefined weak symbol in static links).
We use RLARCH_TLS_GD_IE_NEED_DYN_RELOC macros to determine whether
GD/IE needs dynamic relocation. If GD/IE requires dynamic relocation,
set need_reloc/need_relocs to true and indx to be a dynamic index.
---
bfd/elfnn-loongarch.c | 156 +++++++++++++++++++++++-------------------
1 file changed, 86 insertions(+), 70 deletions(-)
diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
index 172c45ef5cb..68c88e6f52b 100644
--- a/bfd/elfnn-loongarch.c
+++ b/bfd/elfnn-loongarch.c
@@ -159,6 +159,26 @@ struct loongarch_elf_link_hash_table
|| (R_TYPE) == R_LARCH_TLS_LE64_LO20 \
|| (R_TYPE) == R_LARCH_TLS_LE64_HI12)
+/* If TLS GD/IE need dynamic relocations, INDX will be the dynamic indx,
+ and set NEED_RELOC to true used in allocate_dynrelocs and
+ loongarch_elf_relocate_section for TLS GD/IE. */
+#define LARCH_TLS_GD_IE_NEED_DYN_RELOC(INFO, DYN, H, INDX, NEED_RELOC) \
+ do \
+ { \
+ if ((H) != NULL \
+ && (H)->dynindx != -1 \
+ && WILL_CALL_FINISH_DYNAMIC_SYMBOL ((DYN), \
+ bfd_link_pic (INFO), (H))) \
+ (INDX) = (H)->dynindx; \
+ if (((H) == NULL \
+ || ELF_ST_VISIBILITY ((H)->other) == STV_DEFAULT \
+ || (H)->root.type != bfd_link_hash_undefweak) \
+ && (!bfd_link_executable (INFO) \
+ || (INDX) != 0)) \
+ (NEED_RELOC) = true; \
+ } \
+ while (0)
+
/* Generate a PLT header. */
static bool
@@ -1276,40 +1296,24 @@ allocate_dynrelocs (struct elf_link_hash_entry *h, void *inf)
h->got.offset = s->size;
if (tls_type & (GOT_TLS_GD | GOT_TLS_IE | GOT_TLS_GDESC))
{
+ int indx = 0;
+ bool need_reloc = false;
+ LARCH_TLS_GD_IE_NEED_DYN_RELOC (info, dyn, h, indx,
+ need_reloc);
/* TLS_GD needs two dynamic relocs and two GOT slots. */
if (tls_type & GOT_TLS_GD)
{
s->size += 2 * GOT_ENTRY_SIZE;
- if (bfd_link_executable (info))
- {
- /* Link exe and not defined local. */
- if (!SYMBOL_REFERENCES_LOCAL (info, h))
- htab->elf.srelgot->size += 2 * sizeof (ElfNN_External_Rela);
- }
- else
- {
- if (SYMBOL_REFERENCES_LOCAL (info, h))
- htab->elf.srelgot->size += sizeof (ElfNN_External_Rela);
- else
- htab->elf.srelgot->size += 2 * sizeof (ElfNN_External_Rela);
- }
+ if (need_reloc)
+ htab->elf.srelgot->size += 2 * sizeof (ElfNN_External_Rela);
}
/* TLS_IE needs one dynamic reloc and one GOT slot. */
if (tls_type & GOT_TLS_IE)
{
s->size += GOT_ENTRY_SIZE;
-
- if (bfd_link_executable (info))
- {
- /* Link exe and not defined local. */
- if (!SYMBOL_REFERENCES_LOCAL (info, h))
- htab->elf.srelgot->size += sizeof (ElfNN_External_Rela);
- }
- else
- {
- htab->elf.srelgot->size += sizeof (ElfNN_External_Rela);
- }
+ if (need_reloc)
+ htab->elf.srelgot->size += sizeof (ElfNN_External_Rela);
}
/* TLS_DESC needs one dynamic reloc and two GOT slot. */
@@ -2548,6 +2552,19 @@ loongarch_reloc_is_fatal (struct bfd_link_info *info,
})
+#define TP_OFFSET 0
+
+/* Return the relocation value for a static TLS tp-relative relocation. */
+static bfd_vma
+tls_blockoff (struct bfd_link_info *info, bfd_vma addr)
+{
+ /* If tls_sec is NULL, we should have signalled an error already. */
+ if (elf_hash_table (info)->tls_sec == NULL)
+ return 0;
+ return addr - elf_hash_table (info)->tls_sec->vma - TP_OFFSET;
+}
+
+
static int
loongarch_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
bfd *input_bfd, asection *input_section,
@@ -3663,53 +3680,56 @@ loongarch_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
{
Elf_Internal_Rela rela;
asection *relgot = htab->elf.srelgot;
- bfd_vma tls_block_off = 0;
- if (SYMBOL_REFERENCES_LOCAL (info, h))
- {
- BFD_ASSERT (elf_hash_table (info)->tls_sec);
- tls_block_off = relocation
- - elf_hash_table (info)->tls_sec->vma;
- }
+ int indx = 0;
+ bool need_relocs = false;
+ LARCH_TLS_GD_IE_NEED_DYN_RELOC (info, is_dyn, h, indx,
+ need_relocs);
if (tls_type & GOT_TLS_GD)
{
- rela.r_offset = sec_addr (got) + got_off;
- rela.r_addend = 0;
- if (SYMBOL_REFERENCES_LOCAL (info, h))
+ if (need_relocs)
{
- /* Local sym, used in exec, set module id 1. */
- if (bfd_link_executable (info))
- bfd_put_NN (output_bfd, 1, got->contents + got_off);
+ /* Dynamic resolved Module ID. */
+ rela.r_offset = sec_addr (got) + got_off;
+ rela.r_addend = 0;
+ rela.r_info = ELFNN_R_INFO (indx,R_LARCH_TLS_DTPMODNN);
+ bfd_put_NN (output_bfd, 0, got->contents + got_off);
+ loongarch_elf_append_rela (output_bfd, relgot, &rela);
+
+ if (indx == 0)
+ {
+ /* Local symbol, tp offset has been known. */
+ BFD_ASSERT (! unresolved_reloc);
+ bfd_put_NN (output_bfd, tls_blockoff (info,
+ relocation),
+ (got->contents + got_off + GOT_ENTRY_SIZE));
+ }
else
{
- rela.r_info = ELFNN_R_INFO (0, R_LARCH_TLS_DTPMODNN);
+ /* Dynamic resolved block offset. */
+ bfd_put_NN (output_bfd, 0,
+ got->contents + got_off + GOT_ENTRY_SIZE);
+ rela.r_info = ELFNN_R_INFO (indx,
+ R_LARCH_TLS_DTPRELNN);
+ rela.r_offset += GOT_ENTRY_SIZE;
loongarch_elf_append_rela (output_bfd, relgot, &rela);
}
-
- bfd_put_NN (output_bfd, tls_block_off,
- got->contents + got_off + GOT_ENTRY_SIZE);
}
- /* Dynamic resolved. */
else
{
- /* Dynamic relocate module id. */
- rela.r_info = ELFNN_R_INFO (h->dynindx,
- R_LARCH_TLS_DTPMODNN);
- loongarch_elf_append_rela (output_bfd, relgot, &rela);
-
- /* Dynamic relocate offset of block. */
- rela.r_offset += GOT_ENTRY_SIZE;
- rela.r_info = ELFNN_R_INFO (h->dynindx,
- R_LARCH_TLS_DTPRELNN);
- loongarch_elf_append_rela (output_bfd, relgot, &rela);
+ /* In a static link or an executable link with the symbol
+ binding locally. Mark it as belonging to module 1. */
+ bfd_put_NN (output_bfd, 1, got->contents + got_off);
+ bfd_put_NN (output_bfd, tls_blockoff (info, relocation),
+ got->contents + got_off + GOT_ENTRY_SIZE);
}
}
if (tls_type & GOT_TLS_GDESC)
{
/* Unless it is a static link, DESC always emits a
dynamic relocation. */
- int indx = h && h->dynindx != -1 ? h->dynindx : 0;
+ indx = h && h->dynindx != -1 ? h->dynindx : 0;
rela.r_offset = sec_addr (got) + got_off + desc_off;
rela.r_addend = 0;
if (indx == 0)
@@ -3722,28 +3742,24 @@ loongarch_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
}
if (tls_type & GOT_TLS_IE)
{
- rela.r_offset = sec_addr (got) + got_off + ie_off;
- if (SYMBOL_REFERENCES_LOCAL (info, h))
+ if (need_relocs)
{
- /* Local sym, used in exec, set module id 1. */
- if (!bfd_link_executable (info))
- {
- rela.r_info = ELFNN_R_INFO (0, R_LARCH_TLS_TPRELNN);
- rela.r_addend = tls_block_off;
- loongarch_elf_append_rela (output_bfd, relgot, &rela);
- }
+ bfd_put_NN (output_bfd, 0,
+ got->contents + got_off + ie_off);
+ rela.r_offset = sec_addr (got) + got_off + ie_off;
+ rela.r_addend = 0;
- bfd_put_NN (output_bfd, tls_block_off,
- got->contents + got_off + ie_off);
+ if (indx == 0)
+ rela.r_addend = tls_blockoff (info, relocation);
+ rela.r_info = ELFNN_R_INFO (indx, R_LARCH_TLS_TPRELNN);
+ loongarch_elf_append_rela (output_bfd, relgot, &rela);
}
- /* Dynamic resolved. */
else
{
- /* Dynamic relocate offset of block. */
- rela.r_info = ELFNN_R_INFO (h->dynindx,
- R_LARCH_TLS_TPRELNN);
- rela.r_addend = 0;
- loongarch_elf_append_rela (output_bfd, relgot, &rela);
+ /* In a static link or an executable link with the symbol
+ bindinglocally, compute offset directly. */
+ bfd_put_NN (output_bfd, tls_blockoff (info, relocation),
+ got->contents + got_off + ie_off);
}
}
}
--
2.36.0
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