Attachment 15270 Details for Bug 31179 – proposed solution with the tag to keep compatible

[patch] proposed solution with the tag to keep compatible

0001-RISC-V-PR31179-Add-a-reserved-elf-attribute-tag-for-.patch (text/plain), 4.45 KB, created by Nelson Chu on 2023-12-22 05:52:04 UTC

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Creator: Nelson Chu

Created: 2023-12-22 05:52:04 UTC

Size: 4.45 KB

patch

obsolete

>From 43bfb743d24d95354aa94ff36bca96abff521c93 Mon Sep 17 00:00:00 2001
>From: Nelson Chu <nelson@rivosinc.com>
>Date: Fri, 22 Dec 2023 13:34:39 +0800
>Subject: [PATCH] RISC-V: PR31179, Add a reserved elf attribute tag for
> compatible.
>
>The object which marked by the tag means it won't have any non-zero
>addend in SUB_ULEB128, so we don't need to ignore them to get the
>correct calculation.  Since the tag is non-standard in psabi, so
>need use elf_other_obj_attributes_proc rather than
>elf_known_obj_attributes_proc api to access.
>---
> bfd/elfnn-riscv.c     | 27 ++++++++++++++++++++++++---
> binutils/readelf.c    | 15 +++++++++++++++
> gas/config/tc-riscv.c |  8 ++++++++
> include/elf/riscv.h   |  5 ++++-
> 4 files changed, 51 insertions(+), 4 deletions(-)
>
>diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
>index 6a1f1d9884f..f3de6e6cdc8 100644
>--- a/bfd/elfnn-riscv.c
>+++ b/bfd/elfnn-riscv.c
>@@ -1735,9 +1735,30 @@ perform_relocation (const reloc_howto_type *howto,
>   if (howto->pc_relative)
>     value -= sec_addr (input_section) + rel->r_offset;
> 
>-  /* PR31179, ignore the non-zero addend of R_RISCV_SUB_ULEB128.  */
>-  if (ELFNN_R_TYPE (rel->r_info) != R_RISCV_SUB_ULEB128)
>-    value += rel->r_addend;
>+  switch (ELFNN_R_TYPE (rel->r_info))
>+    {
>+    case R_RISCV_SUB_ULEB128:
>+      {
>+        /* PR31179, ignore the non-zero addend of R_RISCV_SUB_ULEB128.  */
>+	obj_attribute_list *list = elf_other_obj_attributes_proc (input_bfd);
>+	for (; list; list = list->next)
>+	  if (list->tag == Tag_RISCV_uleb128_zero_addend && list->attr.i)
>+	    {
>+	      value -= rel->r_addend;
>+	      break;
>+	    }
>+      }
>+      break;
>+    case R_RISCV_SUB6:
>+    case R_RISCV_SUB8:
>+    case R_RISCV_SUB16:
>+    case R_RISCV_SUB32:
>+    case R_RISCV_SUB64:
>+      value -= rel->r_addend;
>+      break;
>+    default:
>+      value += rel->r_addend;
>+    }
> 
>   switch (ELFNN_R_TYPE (rel->r_info))
>     {
>diff --git a/binutils/readelf.c b/binutils/readelf.c
>index 775106fb99c..1eb4f773995 100644
>--- a/binutils/readelf.c
>+++ b/binutils/readelf.c
>@@ -18440,6 +18440,8 @@ static struct riscv_attr_tag_t riscv_attr_tag[] =
>   T(priv_spec_revision),
>   T(unaligned_access),
>   T(stack_align),
>+  /* Non-standard.  */
>+  T(uleb128_zero_addend),
> #undef T
> };
> 
>@@ -18496,6 +18498,19 @@ display_riscv_attribute (unsigned char *p,
>     case Tag_RISCV_arch:
>       p = display_tag_value (-1, p, end);
>       break;
>+    /* Non-standard.  */
>+    case Tag_RISCV_uleb128_zero_addend:
>+      READ_ULEB (val, p, end);
>+      switch (val)
>+	{
>+	  case 0:
>+	    printf (_("no\n"));
>+	    break;
>+	  case 1:
>+	    printf (_("yes\n"));
>+	    break;
>+	}
>+      break;
>     default:
>       return display_tag_value (tag, p, end);
>     }
>diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
>index b902c6ba2c1..9a825310dd8 100644
>--- a/gas/config/tc-riscv.c
>+++ b/gas/config/tc-riscv.c
>@@ -5120,6 +5120,7 @@ riscv_insert_uleb128_fixes (bfd *abfd ATTRIBUTE_UNUSED,
> {
>   segment_info_type *seginfo = seg_info (sec);
>   struct frag *fragP;
>+  bool generate_tag = false;
> 
>   subseg_set (sec, 0);
> 
>@@ -5152,7 +5153,11 @@ riscv_insert_uleb128_fixes (bfd *abfd ATTRIBUTE_UNUSED,
>       fix_new_exp (fragP, fragP->fr_fix, 0,
> 		   exp_dup, 0, BFD_RELOC_RISCV_SUB_ULEB128);
>       free ((void *) exp_dup);
>+      generate_tag = true;
>     }
>+
>+  if (generate_tag)
>+    bfd_elf_add_proc_attr_int (abfd, Tag_RISCV_uleb128_zero_addend, 1);
> }
> 
> /* Called after all assembly has been done.  */
>@@ -5198,12 +5203,15 @@ riscv_convert_symbolic_attribute (const char *name)
>     /* When you modify this table you should
>        also modify the list in doc/c-riscv.texi.  */
> #define T(tag) {#tag, Tag_RISCV_##tag}, {"Tag_RISCV_" #tag, Tag_RISCV_##tag}
>+    /* Standard.  */
>     T(arch),
>     T(priv_spec),
>     T(priv_spec_minor),
>     T(priv_spec_revision),
>     T(unaligned_access),
>     T(stack_align),
>+    /* Non-standard.  */
>+    T(uleb128_zero_addend),
> #undef T
>   };
> 
>diff --git a/include/elf/riscv.h b/include/elf/riscv.h
>index 56d419c665b..9c091f3154c 100644
>--- a/include/elf/riscv.h
>+++ b/include/elf/riscv.h
>@@ -147,12 +147,15 @@ END_RELOC_NUMBERS (R_RISCV_max)
> enum
> {
>   /* 0-3 are generic.  */
>+  /* Standard.  */
>   Tag_RISCV_stack_align = 4,
>   Tag_RISCV_arch = 5,
>   Tag_RISCV_unaligned_access = 6,
>   Tag_RISCV_priv_spec = 8,
>   Tag_RISCV_priv_spec_minor = 10,
>-  Tag_RISCV_priv_spec_revision = 12
>+  Tag_RISCV_priv_spec_revision = 12,
>+  /* Non-standard.  */
>+  Tag_RISCV_uleb128_zero_addend = 32768,
> };
> 
> #endif /* _ELF_RISCV_H */
>-- 
>2.39.3 (Apple Git-145)
>

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Attachments on bug 31179: 15267 | 15270