x86: Restore PC16 relocation overflow check

The x86-64 psABI has

---
A program or object file using R_X86_64_8, R_X86_64_16, R_X86_64_PC16
or R_X86_64_PC8 relocations is not conformant to this ABI, these
relocations are only added for documentation purposes.
---

Since x86 PC16 relocations have been used for 16-bit programs in an ELF32
or ELF64 container, PC16 relocation should wrap-around in 16-bit address
space.  Revert

commit a7664973b24a242cd9ea17deb5eaf503065fc0bd
Author: Jan Beulich <jbeulich@suse.com>
Date:   Mon Apr 26 10:41:35 2021 +0200

    x86: correct overflow checking for 16-bit PC-relative relocs

and xfail the related tests.  Also revert

commit 50c95a739c91ae70cf8481936611aa1f5397a384
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed May 26 12:13:13 2021 -0700

    x86: Propery check PC16 reloc overflow in 16-bit mode instructions

while keeping PR ld/27905 tests for PC16 relocation in 16-bit programs.

bfd/

	PR ld/27905
	* elf32-i386.c: Don't include "libiberty.h".
	(elf_howto_table): Revert commits a7664973b24 and 50c95a739c9.
	(elf_i386_rtype_to_howto): Revert commit 50c95a739c9.
	(elf_i386_info_to_howto_rel): Likewise.
	(elf_i386_tls_transition): Likewise.
	(elf_i386_relocate_section): Likewise.
	* elf64-x86-64.c (x86_64_elf_howto_table): Revert commits
	a7664973b24 and 50c95a739c9.
	(elf_x86_64_rtype_to_howto): Revert commit 50c95a739c9.
	* elfxx-x86.c (_bfd_x86_elf_parse_gnu_properties): Likewise.
	* elfxx-x86.h (elf_x86_obj_tdata): Likewise.
	(elf_x86_has_code16): Likewise.

binutils/

	PR ld/27905
	* readelf.c (decode_x86_feature_2): Revert commit 50c95a739c9.

gas/

	PR ld/27905
	* config/tc-i386.c (set_code_flag): Revert commit 50c95a739c9.
	(set_16bit_gcc_code_flag): Likewise.
	(x86_cleanup): Likewise.
	* testsuite/gas/i386/code16-2.d: Updated.
	* testsuite/gas/i386/x86-64-code16-2.d: Likewise.

include/

	PR ld/27905
	* elf/common.h (GNU_PROPERTY_X86_FEATURE_2_CODE16): Removed.

ld/

	PR ld/27905
	* testsuite/ld-i386/pcrel16-2.d: xfail.
	* testsuite/ld-x86-64/pcrel16-2.d: Likewise.

4 files changed, 27 insertions, 47 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 3e2120d..49d2ceb 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,12 @@
+2021-05-28  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/27905
+	* config/tc-i386.c (set_code_flag): Revert commit 50c95a739c9.
+	(set_16bit_gcc_code_flag): Likewise.
+	(x86_cleanup): Likewise.
+	* testsuite/gas/i386/code16-2.d: Updated.
+	* testsuite/gas/i386/x86-64-code16-2.d: Likewise.
+
 2021-05-27  Peter Bergner  <bergner@linux.ibm.com>
 
 	* testsuite/gas/ppc/vsx.d <xxmr, xxlnot>: Add tests.
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index c17f4da..d344198 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -2695,10 +2695,6 @@ static void
 set_code_flag (int value)
 {
   update_code_flag (value, 0);
-#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
-  if (value == CODE_16BIT)
-    x86_feature_2_used |= GNU_PROPERTY_X86_FEATURE_2_CODE16;
-#endif
 }
 
 static void
@@ -2710,10 +2706,6 @@ set_16bit_gcc_code_flag (int new_code_flag)
   cpu_arch_flags.bitfield.cpu64 = 0;
   cpu_arch_flags.bitfield.cpuno64 = 1;
   stackop_size = LONG_MNEM_SUFFIX;
-#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF)
-  if (new_code_flag == CODE_16BIT)
-    x86_feature_2_used |= GNU_PROPERTY_X86_FEATURE_2_CODE16;
-#endif
 }
 
 static void
@@ -9040,7 +9032,7 @@ x86_cleanup (void)
   unsigned int isa_1_descsz_raw, feature_2_descsz_raw;
   unsigned int padding;
 
-  if (!IS_ELF || (!x86_used_note && !x86_feature_2_used))
+  if (!IS_ELF || !x86_used_note)
     return;
 
   x86_feature_2_used |= GNU_PROPERTY_X86_FEATURE_2_X86;
@@ -9080,23 +9072,15 @@ x86_cleanup (void)
   bfd_set_section_alignment (sec, alignment);
   elf_section_type (sec) = SHT_NOTE;
 
-  if (x86_used_note)
-    {
-      /* GNU_PROPERTY_X86_ISA_1_USED: 4-byte type + 4-byte data size
-	 + 4-byte data  */
-      isa_1_descsz_raw = 4 + 4 + 4;
-      /* Align GNU_PROPERTY_X86_ISA_1_USED.  */
-      isa_1_descsz = (isa_1_descsz_raw + align_size_1) & ~align_size_1;
-    }
-  else
-    {
-      isa_1_descsz_raw = 0;
-      isa_1_descsz = 0;
-    }
+  /* GNU_PROPERTY_X86_ISA_1_USED: 4-byte type + 4-byte data size
+				  + 4-byte data  */
+  isa_1_descsz_raw = 4 + 4 + 4;
+  /* Align GNU_PROPERTY_X86_ISA_1_USED.  */
+  isa_1_descsz = (isa_1_descsz_raw + align_size_1) & ~align_size_1;
 
   feature_2_descsz_raw = isa_1_descsz;
   /* GNU_PROPERTY_X86_FEATURE_2_USED: 4-byte type + 4-byte data size
-     + 4-byte data  */
+				      + 4-byte data  */
   feature_2_descsz_raw += 4 + 4 + 4;
   /* Align GNU_PROPERTY_X86_FEATURE_2_USED.  */
   feature_2_descsz = ((feature_2_descsz_raw + align_size_1)
@@ -9118,23 +9102,20 @@ x86_cleanup (void)
   /* Write n_name.  */
   memcpy (p + 4 * 3, "GNU", 4);
 
-  if (isa_1_descsz != 0)
-    {
-      /* Write 4-byte type.  */
-      md_number_to_chars (p + 4 * 4,
-			  (valueT) GNU_PROPERTY_X86_ISA_1_USED, 4);
+  /* Write 4-byte type.  */
+  md_number_to_chars (p + 4 * 4,
+		      (valueT) GNU_PROPERTY_X86_ISA_1_USED, 4);
 
-      /* Write 4-byte data size.  */
-      md_number_to_chars (p + 4 * 5, (valueT) 4, 4);
+  /* Write 4-byte data size.  */
+  md_number_to_chars (p + 4 * 5, (valueT) 4, 4);
 
-      /* Write 4-byte data.  */
-      md_number_to_chars (p + 4 * 6, (valueT) x86_isa_1_used, 4);
+  /* Write 4-byte data.  */
+  md_number_to_chars (p + 4 * 6, (valueT) x86_isa_1_used, 4);
 
-      /* Zero out paddings.  */
-      padding = isa_1_descsz - isa_1_descsz_raw;
-      if (padding)
-	memset (p + 4 * 7, 0, padding);
-    }
+  /* Zero out paddings.  */
+  padding = isa_1_descsz - isa_1_descsz_raw;
+  if (padding)
+    memset (p + 4 * 7, 0, padding);
 
   /* Write 4-byte type.  */
   md_number_to_chars (p + isa_1_descsz + 4 * 4,
diff --git a/gas/testsuite/gas/i386/code16-2.d b/gas/testsuite/gas/i386/code16-2.d
index 37b66c8..f18c8cd 100644
--- a/gas/testsuite/gas/i386/code16-2.d
+++ b/gas/testsuite/gas/i386/code16-2.d
@@ -1,8 +1,3 @@
 #name: i386 code16 2
 #as: -mx86-used-note=no --generate-missing-build-notes=no
 #readelf: -n
-
-Displaying notes found in: .note.gnu.property
-[ 	]+Owner[ 	]+Data size[ 	]+Description
-  GNU                  0x[0-9a-f]+	NT_GNU_PROPERTY_TYPE_0
-      Properties: x86 feature used: x86, CODE16
diff --git a/gas/testsuite/gas/i386/x86-64-code16-2.d b/gas/testsuite/gas/i386/x86-64-code16-2.d
index dbabd67..5052353 100644
--- a/gas/testsuite/gas/i386/x86-64-code16-2.d
+++ b/gas/testsuite/gas/i386/x86-64-code16-2.d
@@ -2,8 +2,3 @@
 #name: x86-64 code16 2
 #as: -mx86-used-note=no --generate-missing-build-notes=no
 #readelf: -n
-
-Displaying notes found in: .note.gnu.property
-[ 	]+Owner[ 	]+Data size[ 	]+Description
-  GNU                  0x[0-9a-f]+	NT_GNU_PROPERTY_TYPE_0
-      Properties: x86 feature used: x86, CODE16