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From: Lulu Cai <cailulu@loongson.cn>
To: binutils@sourceware.org
Cc: xuchenghua@loongson.cn, chenglulu@loongson.cn,
	liuzhensong@loongson.cn, mengqinggang@loongson.cn,
	xry111@xry111.site, i.swmail@xen0n.name, maskray@google.com,
	luweining@loongson.cn, wanglei@loongson.cn,
	hejinyang@loongson.cn, Lulu Cai <cailulu@loongson.cn>
Subject: [PATCH] LoongArch: Fix the issue of excessive relocation generated by IE
Date: Sun,  4 Feb 2024 11:18:19 +0800	[thread overview]
Message-ID: <20240204031819.3982654-1-cailulu@loongson.cn> (raw)

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


             reply	other threads:[~2024-02-04  3:18 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-04  3:18 Lulu Cai [this message]
  -- strict thread matches above, loose matches on Subject: below --
2024-01-23 13:00 Lulu Cai

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