From 41abd06f7ba97c5b92a2d38c99c357772bba3ade Mon Sep 17 00:00:00 2001
From: Xin Wang <[email protected]>
Date: Fri, 16 Aug 2024 11:28:10 +0800
Subject: [PATCH 113/123] Not append rela for absolute symbol

LoongArch: Not append rela for absolute symbol

Use la.global to get absolute symbol like la.abs.
la.global put address of a global symbol into a got
entry and append a rela for it, which will be used
to relocate by dynamic linker. Dynamic linker should
not relocate for got entry of absolute symbol as it
stores symval not symbol's address.
---
 bfd/elfnn-loongarch.c                         | 19 ++++++++++++++++++-
 ld/testsuite/ld-loongarch-elf/abs-global.out  |  1 +
 ld/testsuite/ld-loongarch-elf/abs-global.s    |  5 +++++
 .../ld-loongarch-elf/get_abs_global_sym.c     |  7 +++++++
 .../ld-loongarch-elf/ld-loongarch-elf.exp     | 12 ++++++++++++
 5 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 ld/testsuite/ld-loongarch-elf/abs-global.out
 create mode 100644 ld/testsuite/ld-loongarch-elf/abs-global.s
 create mode 100644 ld/testsuite/ld-loongarch-elf/get_abs_global_sym.c

diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
index 770483cd..09a9513b 100644
--- a/bfd/elfnn-loongarch.c
+++ b/bfd/elfnn-loongarch.c
@@ -4135,6 +4135,7 @@ loongarch_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
 		      if (!WILL_CALL_FINISH_DYNAMIC_SYMBOL (is_dyn,
 							    bfd_link_pic (info),
 							    h)
+			  && !bfd_is_abs_section(h->root.u.def.section)
 			  && bfd_link_pic (info)
 			  && LARCH_REF_LOCAL (info, h)
 			  && !info->enable_dt_relr)
@@ -4157,7 +4158,8 @@ loongarch_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
 			      && local_got_offsets[r_symndx] != MINUS_ONE);
 
 		  got_off = local_got_offsets[r_symndx] & (~(bfd_vma)1);
-		  if ((local_got_offsets[r_symndx] & 1) == 0)
+		  if (sym->st_shndx != SHN_ABS
+		      && (local_got_offsets[r_symndx] & 1) == 0)
 		    {
 		      if (bfd_link_pic (info) && !info->enable_dt_relr)
 			{
@@ -5314,6 +5316,7 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
       bfd_vma symval;
       asection *sym_sec;
       bool local_got = false;
+      bool is_abs_symbol = false;
       Elf_Internal_Rela *rel = relocs + i;
       struct elf_link_hash_entry *h = NULL;
       unsigned long r_type = ELFNN_R_TYPE (rel->r_info);
@@ -5495,7 +5498,21 @@ loongarch_elf_relax_section (bfd *abfd, asection *sec,
 	  break;
 
 	case R_LARCH_GOT_PC_HI20:
+	  if (h)
+	    is_abs_symbol = bfd_is_abs_section(h->root.u.def.section);
+	  else
+	    {
+	      Elf_Internal_Sym *sym = (Elf_Internal_Sym *)symtab_hdr->contents
+				    + ELFNN_R_SYM (rel->r_info);
+	      is_abs_symbol = sym->st_shndx == SHN_ABS;
+	    }
+	 /* If symval is in the range [-2^31, 2^31), we can relax the
+	    pair of instructions from pcalau12i/ld.d to lu12i.w/ori for
+	    abosulte symbol. This is not implemented yet, so we just
+	    remain the r_type which will be needed when relocate for
+	    absolute symbol. */
 	  if (local_got && 0 == info->relax_pass
+	      && !is_abs_symbol
 	      && (i + 4) <= sec->reloc_count)
 	    {
 	      if (loongarch_relax_pcala_ld (abfd, sec, rel))
diff --git a/ld/testsuite/ld-loongarch-elf/abs-global.out b/ld/testsuite/ld-loongarch-elf/abs-global.out
new file mode 100644
index 00000000..3656652b
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/abs-global.out
@@ -0,0 +1 @@
+abba
diff --git a/ld/testsuite/ld-loongarch-elf/abs-global.s b/ld/testsuite/ld-loongarch-elf/abs-global.s
new file mode 100644
index 00000000..93a5da6d
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/abs-global.s
@@ -0,0 +1,5 @@
+.text
+.globl get_sym
+get_sym:
+ la.global $a0, sym
+ ret
diff --git a/ld/testsuite/ld-loongarch-elf/get_abs_global_sym.c b/ld/testsuite/ld-loongarch-elf/get_abs_global_sym.c
new file mode 100644
index 00000000..29781ad7
--- /dev/null
+++ b/ld/testsuite/ld-loongarch-elf/get_abs_global_sym.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+extern int get_sym();
+int main() {
+	printf("%x\n", get_sym());
+	return 0;
+}
diff --git a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
index cb6d2296..555ebf92 100644
--- a/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
+++ b/ld/testsuite/ld-loongarch-elf/ld-loongarch-elf.exp
@@ -130,6 +130,18 @@ if [istarget "loongarch64-*-*"] {
 		"a.binary" \
 	   ] \
       ]
+
+
+  run_ld_link_exec_tests [list \
+	[list \
+	    "get global abs symbol test" \
+	    "-Wl,-z norelro -Wl,--defsym sym=0xabba" \
+	    "" \
+	    { abs-global.s get_abs_global_sym.c} \
+	    "abs-global" \
+	    "abs-global.out" \
+	] \
+    ]
 }
 
 if [istarget "loongarch64-*-*"] {
-- 
2.33.0