[binutils-gdb] [PR ld/22263][PR ld/25694] RISC-V: Avoid dynamic TLS relocs in PIE.

[binutils-gdb] [PR ld/22263][PR ld/25694] RISC-V: Avoid dynamic TLS relocs in PIE.

[Nelson Chu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=225df051d3d4cf714d1791b9035966a6686b3f3d

commit 225df051d3d4cf714d1791b9035966a6686b3f3d
Author: Nelson Chu <nelson@nelson.ba.rivosinc.com>
Date:   Thu May 4 17:08:50 2023 +0800

    [PR ld/22263][PR ld/25694] RISC-V: Avoid dynamic TLS relocs in PIE.
    
    Lots of targets already fixed the TEXTREL problem for TLS in PIE.
    
    * For PR ld/25694,
    In the check_reloc, refer to spare and loongarch, they don't need to reserve
    any local dynamic reloc for TLS LE in pie/pde, and similar to other targets.
    So it seems like riscv was too conservative to estimate the TLS LE before.
    Just break and don't goto static_reloc for TLS LE in pie/pde can fix the
    TEXTREL problem.
    
    * For PR ld/22263,
    The risc-v code for TLS GD/IE in the relocate_section seems same as MIPS port.
    So similar to MIPS, pr22570, commits 9143e72c6d4d and 1cb83cac9a89, it seems
    also the right way to do the same thing for risc-v.
    
    On risc-v, fixes
    FAIL: Build pr22263-1
    
    RISC-V haven't supported the TLS transitions, so will need the same fix (use
    bfd_link_dll) in the future.
    
    bfd/
            PR ld/22263
            PR ld/25694
            * elfnn-riscv.c (riscv_elf_check_relocs): Replace bfd_link_pic with
            bfd_link_dll for TLS IE.  Don't need to reserve the local dynamic
            relocation for TLS LE in pie/pde, and report error in pic just like
            before.
            (riscv_elf_relocate_section): For TLS GD/IE, use bfd_link_dll rather
            than !bfd_link_pic in determining the dynamic symbol index.  Avoid
            the index of -1.

Diff:
---
 bfd/elfnn-riscv.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index 75af040cf92..762ea231c0b 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -824,7 +824,7 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
 	  break;
 
 	case R_RISCV_TLS_GOT_HI20:
-	  if (bfd_link_pic (info))
+	  if (bfd_link_dll (info))
 	    info->flags |= DF_STATIC_TLS;
 	  if (!riscv_elf_record_got_reference (abfd, info, h, r_symndx)
 	      || !riscv_elf_record_tls_type (abfd, h, r_symndx, GOT_TLS_IE))
@@ -920,11 +920,12 @@ riscv_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
 	  goto static_reloc;
 
 	case R_RISCV_TPREL_HI20:
+	  /* This is not allowed in the pic, but okay in pie.  */
 	  if (!bfd_link_executable (info))
 	    return bad_static_reloc (abfd, r_type, h);
 	  if (h != NULL)
 	    riscv_elf_record_tls_type (abfd, h, r_symndx, GOT_TLS_LE);
-	  goto static_reloc;
+	  break;
 
 	case R_RISCV_HI20:
 	  if (bfd_link_pic (info))
@@ -2880,24 +2881,20 @@ riscv_elf_relocate_section (bfd *output_bfd,
 	      if (htab->elf.srelgot == NULL)
 		abort ();
 
-	      if (h != NULL)
-		{
-		  bool dyn, pic;
-		  dyn = htab->elf.dynamic_sections_created;
-		  pic = bfd_link_pic (info);
-
-		  if (WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, pic, h)
-		      && (!pic || !SYMBOL_REFERENCES_LOCAL (info, h)))
-		    indx = h->dynindx;
-		}
+	      bool dyn = elf_hash_table (info)->dynamic_sections_created;
+	      if (h != NULL
+		  && h->dynindx != -1
+		  && WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, bfd_link_pic (info), h)
+		  && (bfd_link_dll (info) || !SYMBOL_REFERENCES_LOCAL (info, h)))
+		indx = h->dynindx;
 
 	      /* The GOT entries have not been initialized yet.  Do it
 		 now, and emit any relocations.  */
-	      if ((bfd_link_pic (info) || indx != 0)
+	      if ((bfd_link_dll (info) || indx != 0)
 		  && (h == NULL
 		      || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
 		      || h->root.type != bfd_link_hash_undefweak))
-		    need_relocs = true;
+		need_relocs = true;
 
 	      if (tls_type & GOT_TLS_GD)
 		{