Add support for COFF secidx relocations

bfd	* coff-i386.c (in_reloc_p): Add R_SECTION.
	(howto_table): Add R_SECTION.
	(coff_pe_i386_relocation_section): Add support for R_SECTION.
	(coff_i386_reloc_type_lookup): Add support for
	BFD_RELOC_16_SECCIDX.
	* coff-x86_64.c (in_reloc_p): Add R_SECTION.
	(howto_table): Add R_SECTION.
	(coff_pe_amd64_relocation_section): Add support for R_SECTION.
	(coff_amd64_reloc_type_lookup): Add support for
	BFD_RELOC_16_SECCIDX.
	* reloc.c: Add BFD_RELOC_16_SECIDX.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.

gas	* config/tc-i386.c (pe_directive_secidx): New function.
	(md_pseudo_table): Add support for secidx.
	(x86_cons_fix_new): Likewise.
	(tc_gen_reloc): Likewise.
	* expr.c (op_rank): Add O_secidx.
	* expr.h (operatorT): Likewise.
	* symbols.c (resolve_symbol_value): Add support for O_secidx.
	* testsuite/gas/i386/secidx.s: New test source file.
	* testsuite/gas/i386/secidx.d: New test driver file.
	* testsuite/gas/i386/i386.exp: Run new test.

include	* coff/i386.h: Define R_SECTION.
	* coff/x86_64.h: Likewise.

ld	* testsuite/ld-pe/secidx1.s: New test source file.
	* testsuite/ld-pe/secidx2.s: New test source file.
	* testsuite/ld-pe/secidx.d: New test driver file.
	* testsuite/ld-pe/secidx_64.d: New test driver file.
	* testsuite/ld-pe/pe.exp: Add new tests.

6 files changed, 206 insertions, 12 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 98f0bab..5b53258 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,19 @@
+2022-04-07  Mark Harmstone  <mark@harmstone.com>
+
+	* coff-i386.c (in_reloc_p): Add R_SECTION.
+	(howto_table): Add R_SECTION.
+	(coff_pe_i386_relocation_section): Add support for R_SECTION.
+	(coff_i386_reloc_type_lookup): Add support for
+	BFD_RELOC_16_SECCIDX.
+	* coff-x86_64.c (in_reloc_p): Add R_SECTION.
+	(howto_table): Add R_SECTION.
+	(coff_pe_amd64_relocation_section): Add support for R_SECTION.
+	(coff_amd64_reloc_type_lookup): Add support for
+	BFD_RELOC_16_SECCIDX.
+	* reloc.c: Add BFD_RELOC_16_SECIDX.
+	* bfd-in2.h: Regenerate.
+	* libbfd.h: Regenerate.
+
 2022-04-01  John Baldwin  <jhb@FreeBSD.org>
 
 	* elf-bfd.h (elfcore_write_x86_segbases): New.
diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 404dae2..eb3b79e 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -2229,6 +2229,7 @@ the section containing the relocation.  It depends on the specific target.  */
 
 /* Section relative relocations.  Some targets need this for DWARF2.  */
   BFD_RELOC_32_SECREL,
+  BFD_RELOC_16_SECIDX,
 
 /* For ELF.  */
   BFD_RELOC_32_GOT_PCREL,
diff --git a/bfd/coff-i386.c b/bfd/coff-i386.c
index 0670c59..32a4993 100644
--- a/bfd/coff-i386.c
+++ b/bfd/coff-i386.c
@@ -190,8 +190,10 @@ coff_i386_reloc (bfd *abfd,
 static bool
 in_reloc_p (bfd *abfd ATTRIBUTE_UNUSED, reloc_howto_type *howto)
 {
-  return ! howto->pc_relative && howto->type != R_IMAGEBASE
-	 && howto->type != R_SECREL32;
+  return ! howto->pc_relative
+    && howto->type != R_IMAGEBASE
+    && howto->type != R_SECREL32
+    && howto->type != R_SECTION;
 }
 #endif /* COFF_WITH_PE */
 
@@ -236,8 +238,21 @@ static reloc_howto_type howto_table[] =
 	 false),		/* pcrel_offset */
   EMPTY_HOWTO (010),
   EMPTY_HOWTO (011),
-  EMPTY_HOWTO (012),
 #ifdef COFF_WITH_PE
+  /* 16-bit word section relocation (012).  */
+  HOWTO (R_SECTION,		/* type */
+	 0,			/* rightshift */
+	 1,			/* size (0 = byte, 1 = short, 2 = long) */
+	 16,			/* bitsize */
+	 false,			/* pc_relative */
+	 0,			/* bitpos */
+	 complain_overflow_bitfield, /* complain_on_overflow */
+	 coff_i386_reloc,	/* special_function */
+	 "secidx",		/* name */
+	 true,			/* partial_inplace */
+	 0xffffffff,		/* src_mask */
+	 0xffffffff,		/* dst_mask */
+	 true),			/* pcrel_offset */
   /* 32-bit longword section relative relocation (013).  */
   HOWTO (R_SECREL32,		/* type */
 	 0,			/* rightshift */
@@ -253,6 +268,7 @@ static reloc_howto_type howto_table[] =
 	 0xffffffff,		/* dst_mask */
 	 true),			/* pcrel_offset */
 #else
+  EMPTY_HOWTO (012),
   EMPTY_HOWTO (013),
 #endif
   EMPTY_HOWTO (014),
@@ -407,9 +423,9 @@ static reloc_howto_type howto_table[] =
 
 #else /* COFF_WITH_PE */
 
-/* The PE relocate section routine.  The only difference between this
-   and the regular routine is that we don't want to do anything for a
-   relocatable link.  */
+/* The PE relocate section routine.  We handle secidx relocations here,
+   as well as making sure that we don't do anything for a relocatable
+   link.  */
 
 static bool
 coff_pe_i386_relocate_section (bfd *output_bfd,
@@ -421,9 +437,78 @@ coff_pe_i386_relocate_section (bfd *output_bfd,
 			       struct internal_syment *syms,
 			       asection **sections)
 {
+  struct internal_reloc *rel;
+  struct internal_reloc *relend;
+
   if (bfd_link_relocatable (info))
     return true;
 
+  rel = relocs;
+  relend = rel + input_section->reloc_count;
+
+  for (; rel < relend; rel++)
+    {
+      long symndx;
+      struct coff_link_hash_entry *h;
+      asection *sec, *s;
+      uint16_t idx = 0, i = 1;
+
+      if (rel->r_type != R_SECTION)
+	continue;
+
+      /* Make sure that _bfd_coff_generic_relocate_section won't parse
+         this reloc after us.  */
+      rel->r_type = 0;
+
+      symndx = rel->r_symndx;
+
+      if (symndx < 0
+	  || (unsigned long) symndx >= obj_raw_syment_count (input_bfd))
+	continue;
+
+      h = obj_coff_sym_hashes (input_bfd)[symndx];
+
+      if (h == NULL)
+	sec = sections[symndx];
+      else
+	{
+	  if (h->root.type == bfd_link_hash_defined
+	      || h->root.type == bfd_link_hash_defweak)
+	    {
+	      /* Defined weak symbols are a GNU extension.  */
+	      sec = h->root.u.def.section;
+	    }
+	  else
+	    {
+	      sec = NULL;
+	    }
+	}
+
+      if (!sec)
+	continue;
+
+      if (bfd_is_abs_section (sec))
+	continue;
+
+      if (discarded_section (sec))
+	continue;
+
+      s = output_bfd->sections;
+      while (s)
+	{
+	  if (s == sec->output_section)
+	    {
+	      idx = i;
+	      break;
+	    }
+
+	  i++;
+	  s = s->next;
+	}
+
+      bfd_putl16 (idx, contents + rel->r_vaddr - input_section->vma);
+    }
+
   return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,
 					     input_section, contents,
 					     relocs, syms, sections);
@@ -573,6 +658,8 @@ coff_i386_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
 #ifdef COFF_WITH_PE
     case BFD_RELOC_32_SECREL:
       return howto_table + R_SECREL32;
+    case BFD_RELOC_16_SECIDX:
+      return howto_table + R_SECTION;
 #endif
     default:
       BFD_FAIL ();
diff --git a/bfd/coff-x86_64.c b/bfd/coff-x86_64.c
index c2da0f4..e8e16d3 100644
--- a/bfd/coff-x86_64.c
+++ b/bfd/coff-x86_64.c
@@ -224,8 +224,10 @@ coff_amd64_reloc (bfd *abfd,
 static bool
 in_reloc_p (bfd *abfd ATTRIBUTE_UNUSED, reloc_howto_type *howto)
 {
-  return ! howto->pc_relative && howto->type != R_AMD64_IMAGEBASE
-	 && howto->type != R_AMD64_SECREL;
+  return ! howto->pc_relative
+    && howto->type != R_AMD64_IMAGEBASE
+    && howto->type != R_AMD64_SECREL
+    && howto->type != R_AMD64_SECTION;
 }
 #endif /* COFF_WITH_PE */
 
@@ -356,8 +358,21 @@ static reloc_howto_type howto_table[] =
 	 0xffffffff,		/* src_mask */
 	 0xffffffff,		/* dst_mask */
 	 PCRELOFFSET),		/* pcrel_offset */
-  EMPTY_HOWTO (10), /* R_AMD64_SECTION 10  */
 #if defined(COFF_WITH_PE)
+  /* 16-bit word section relocation (10).  */
+  HOWTO (R_AMD64_SECTION,	/* type */
+	 0,			/* rightshift */
+	 1,			/* size (0 = byte, 1 = short, 2 = long) */
+	 16,			/* bitsize */
+	 false,			/* pc_relative */
+	 0,			/* bitpos */
+	 complain_overflow_bitfield, /* complain_on_overflow */
+	 coff_amd64_reloc,	/* special_function */
+	 "IMAGE_REL_AMD64_SECTION", /* name */
+	 true,			/* partial_inplace */
+	 0x0000ffff,		/* src_mask */
+	 0x0000ffff,		/* dst_mask */
+	 true),
   /* 32-bit longword section relative relocation (11).  */
   HOWTO (R_AMD64_SECREL,	/* type */
 	 0,			/* rightshift */
@@ -373,6 +388,7 @@ static reloc_howto_type howto_table[] =
 	 0xffffffff,		/* dst_mask */
 	 true),			/* pcrel_offset */
 #else
+  EMPTY_HOWTO (10),
   EMPTY_HOWTO (11),
 #endif
   EMPTY_HOWTO (12),
@@ -545,9 +561,9 @@ static reloc_howto_type howto_table[] =
 
 #else /* COFF_WITH_PE */
 
-/* The PE relocate section routine.  The only difference between this
-   and the regular routine is that we don't want to do anything for a
-   relocatable link.  */
+/* The PE relocate section routine.  We handle secidx relocations here,
+   as well as making sure that we don't do anything for a relocatable
+   link.  */
 
 static bool
 coff_pe_amd64_relocate_section (bfd *output_bfd,
@@ -559,9 +575,78 @@ coff_pe_amd64_relocate_section (bfd *output_bfd,
 				struct internal_syment *syms,
 				asection **sections)
 {
+  struct internal_reloc *rel;
+  struct internal_reloc *relend;
+
   if (bfd_link_relocatable (info))
     return true;
 
+  rel = relocs;
+  relend = rel + input_section->reloc_count;
+
+  for (; rel < relend; rel++)
+    {
+      long symndx;
+      struct coff_link_hash_entry *h;
+      asection *sec, *s;
+      uint16_t idx = 0, i = 1;
+
+      if (rel->r_type != R_SECTION)
+	continue;
+
+      /* Make sure that _bfd_coff_generic_relocate_section won't parse
+         this reloc after us.  */
+      rel->r_type = 0;
+
+      symndx = rel->r_symndx;
+
+      if (symndx < 0
+	  || (unsigned long) symndx >= obj_raw_syment_count (input_bfd))
+	continue;
+
+      h = obj_coff_sym_hashes (input_bfd)[symndx];
+
+      if (h == NULL)
+	sec = sections[symndx];
+      else
+	{
+	  if (h->root.type == bfd_link_hash_defined
+	      || h->root.type == bfd_link_hash_defweak)
+	    {
+	      /* Defined weak symbols are a GNU extension.  */
+	      sec = h->root.u.def.section;
+	    }
+	  else
+	    {
+	      sec = NULL;
+	    }
+	}
+
+      if (!sec)
+	continue;
+
+      if (bfd_is_abs_section (sec))
+	continue;
+
+      if (discarded_section (sec))
+	continue;
+
+      s = output_bfd->sections;
+      while (s)
+	{
+	  if (s == sec->output_section)
+	    {
+	      idx = i;
+	      break;
+	    }
+
+	  i++;
+	  s = s->next;
+	}
+
+      bfd_putl16 (idx, contents + rel->r_vaddr - input_section->vma);
+    }
+
   return _bfd_coff_generic_relocate_section (output_bfd, info, input_bfd,input_section, contents,relocs, syms, sections);
 }
 
@@ -716,6 +801,8 @@ coff_amd64_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED, bfd_reloc_code_real_ty
 #if defined(COFF_WITH_PE)
     case BFD_RELOC_32_SECREL:
       return howto_table + R_AMD64_SECREL;
+    case BFD_RELOC_16_SECIDX:
+      return howto_table + R_AMD64_SECTION;
 #endif
     default:
       BFD_FAIL ();
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index 6e62e55..8c02e29 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -1040,6 +1040,7 @@ static const char *const bfd_reloc_code_real_names[] = { "@@uninitialized@@",
   "BFD_RELOC_12_PCREL",
   "BFD_RELOC_8_PCREL",
   "BFD_RELOC_32_SECREL",
+  "BFD_RELOC_16_SECIDX",
   "BFD_RELOC_32_GOT_PCREL",
   "BFD_RELOC_16_GOT_PCREL",
   "BFD_RELOC_8_GOT_PCREL",
diff --git a/bfd/reloc.c b/bfd/reloc.c
index 1640603..5098e0a 100644
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -1621,6 +1621,8 @@ the section containing the relocation.  It depends on the specific target.
 
 ENUM
   BFD_RELOC_32_SECREL
+ENUMX
+  BFD_RELOC_16_SECIDX
 ENUMDOC
   Section relative relocations.  Some targets need this for DWARF2.