[ARM] Add FDPIC OSABI flag support.

ELF files targetting ARM FDPIC use the ELFOSABI_ARM_FDPIC flag.
Set it appropriately in file generators (eg. gas), and handle it in
readers (eg. readelf).

2018-04-25  Christophe Lyon  <christophe.lyon@st.com>
	Mickaël Guêné  <mickael.guene@st.com>

	bfd/
	* elf32-arm.c (elf32_arm_print_private_bfd_data): Support
	EF_ARM_PIC and ELFOSABI_ARM_FDPIC.
	(elf32_arm_post_process_headers): Support ELFOSABI_ARM_FDPIC.
	(ELF_OSABI): Define to ELFOSABI_ARM_FDPIC.

	binutils/
	* readelf.c (decode_ARM_machine_flags): Support EF_ARM_PIC.
	(get_osabi_name): Support ELFOSABI_ARM_FDPIC.

	gas/
	* config/tc-arm.c (arm_fdpic): New.
	(elf32_arm_target_format): Support FDPIC.
	(OPTION_FDPIC): New.
	(md_longopts): Support FDPIC.
	(md_parse_option): Likewise.
	(md_show_usage): Likewise.

	include/
	* elf/arm.h (EF_ARM_FDPIC): New.

8 files changed, 81 insertions, 4 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index ed96fcd..dd28d04 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,6 +1,14 @@
 2018-04-25  Christophe Lyon  <christophe.lyon@st.com>
 	Mickaël Guêné  <mickael.guene@st.com>
 
+	* elf32-arm.c (elf32_arm_print_private_bfd_data): Support
+	EF_ARM_PIC and ELFOSABI_ARM_FDPIC.
+	(elf32_arm_post_process_headers): Support ELFOSABI_ARM_FDPIC.
+	(ELF_OSABI): Define to ELFOSABI_ARM_FDPIC.
+
+2018-04-25  Christophe Lyon  <christophe.lyon@st.com>
+	Mickaël Guêné  <mickael.guene@st.com>
+
 	* config.bfd (arm*-*-linux-*): Add arm_elf32_fdpic_be_vec and
 	arm_elf32_fdpic_le_vec to targ_selvecs. Accept
 	arm*-*-uclinuxfdpiceabi.
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 565bb40..a0b0be3 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -14280,7 +14280,13 @@ elf32_arm_print_private_bfd_data (bfd *abfd, void * ptr)
   if (flags & EF_ARM_RELEXEC)
     fprintf (file, _(" [relocatable executable]"));
 
-  flags &= ~EF_ARM_RELEXEC;
+  if (flags & EF_ARM_PIC)
+    fprintf (file, _(" [position independent]"));
+
+  if (elf_elfheader (abfd)->e_ident[EI_OSABI] == ELFOSABI_ARM_FDPIC)
+    fprintf (file, _(" [FDPIC ABI supplement]"));
+
+  flags &= ~ (EF_ARM_RELEXEC | EF_ARM_PIC);
 
   if (flags)
     fprintf (file, _("<Unrecognised flag bits set>"));
@@ -16642,6 +16648,9 @@ elf32_arm_post_process_headers (bfd * abfd, struct bfd_link_info * link_info ATT
       globals = elf32_arm_hash_table (link_info);
       if (globals != NULL && globals->byteswap_code)
 	i_ehdrp->e_flags |= EF_ARM_BE8;
+
+      if (globals->fdpic_p)
+	i_ehdrp->e_ident[EI_OSABI] |= ELFOSABI_ARM_FDPIC;
     }
 
   if (EF_ARM_EABI_VERSION (i_ehdrp->e_flags) == EF_ARM_EABI_VER5
@@ -19427,6 +19436,8 @@ elf32_arm_nacl_plt_sym_val (bfd_vma i, const asection *plt,
 #define TARGET_BIG_NAME			"elf32-bigarm-fdpic"
 #undef elf_match_priority
 #define elf_match_priority		128
+#undef ELF_OSABI
+#define ELF_OSABI		ELFOSABI_ARM_FDPIC
 
 /* Like elf32_arm_link_hash_table_create -- but overrides
    appropriately for FDPIC.  */
@@ -19454,6 +19465,7 @@ elf32_arm_fdpic_link_hash_table_create (bfd *abfd)
 
 #include "elf32-target.h"
 #undef elf_match_priority
+#undef ELF_OSABI
 
 /* VxWorks Targets.  */
 
diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index 2b2c709..68e5175 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,9 @@
+2018-04-25  Christophe Lyon  <christophe.lyon@st.com>
+	Mickaël Guêné  <mickael.guene@st.com>
+
+	* readelf.c (decode_ARM_machine_flags): Support EF_ARM_PIC.
+	(get_osabi_name): Support ELFOSABI_ARM_FDPIC.
+
 2018-04-25  Alan Modra  <amodra@gmail.com>
 
 	* testsuite/binutils-all/arm/objdump.exp: Remove arm-aout and
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 528954c..e8e1b96 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -2578,6 +2578,12 @@ decode_ARM_machine_flags (unsigned e_flags, char buf[])
       e_flags &= ~ EF_ARM_RELEXEC;
     }
 
+  if (e_flags & EF_ARM_PIC)
+    {
+      strcat (buf, ", position independent");
+      e_flags &= ~ EF_ARM_PIC;
+    }
+
   /* Now handle EABI specific flags.  */
   switch (eabi)
     {
@@ -3718,6 +3724,7 @@ get_osabi_name (Filedata * filedata, unsigned int osabi)
 	    switch (osabi)
 	      {
 	      case ELFOSABI_ARM:	return "ARM";
+	      case ELFOSABI_ARM_FDPIC:	return "ARM FDPIC";
 	      default:
 		break;
 	      }
diff --git a/gas/ChangeLog b/gas/ChangeLog
index e8c0f7d..5db76c9 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2018-04-25  Christophe Lyon  <christophe.lyon@st.com>
+	Mickaël Guêné  <mickael.guene@st.com>
+
+	* config/tc-arm.c (arm_fdpic): New.
+	(elf32_arm_target_format): Support FDPIC.
+	(OPTION_FDPIC): New.
+	(md_longopts): Support FDPIC.
+	(md_parse_option): Likewise.
+	(md_show_usage): Likewise.
+
 2018-04-25  Tamar Christina  <tamar.christina@arm.com>
 
 	* testsuite/gas/aarch64/rdma.s: Test for larger register numbers.
diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c
index f7bddd7..d735609 100644
--- a/gas/config/tc-arm.c
+++ b/gas/config/tc-arm.c
@@ -75,6 +75,9 @@ static struct
   unsigned	  sp_restored:1;
 } unwind;
 
+/* Whether --fdpic was given.  */
+static int arm_fdpic;
+
 #endif /* OBJ_ELF */
 
 /* Results from operand parsing worker functions.  */
@@ -25079,10 +25082,20 @@ elf32_arm_target_format (void)
 	  ? "elf32-bigarm-nacl"
 	  : "elf32-littlearm-nacl");
 #else
-  if (target_big_endian)
-    return "elf32-bigarm";
+  if (arm_fdpic)
+    {
+      if (target_big_endian)
+	return "elf32-bigarm-fdpic";
+      else
+	return "elf32-littlearm-fdpic";
+    }
   else
-    return "elf32-littlearm";
+    {
+      if (target_big_endian)
+	return "elf32-bigarm";
+      else
+	return "elf32-littlearm";
+    }
 #endif
 }
 
@@ -25602,6 +25615,7 @@ const char * md_shortopts = "m:k";
 #endif
 #endif
 #define OPTION_FIX_V4BX (OPTION_MD_BASE + 2)
+#define OPTION_FDPIC (OPTION_MD_BASE + 3)
 
 struct option md_longopts[] =
 {
@@ -25612,6 +25626,9 @@ struct option md_longopts[] =
   {"EL", no_argument, NULL, OPTION_EL},
 #endif
   {"fix-v4bx", no_argument, NULL, OPTION_FIX_V4BX},
+#ifdef OBJ_ELF
+  {"fdpic", no_argument, NULL, OPTION_FDPIC},
+#endif
   {NULL, no_argument, NULL, 0}
 };
 
@@ -26783,6 +26800,12 @@ md_parse_option (int c, const char * arg)
       fix_v4bx = TRUE;
       break;
 
+#ifdef OBJ_ELF
+    case OPTION_FDPIC:
+      arm_fdpic = TRUE;
+      break;
+#endif /* OBJ_ELF */
+
     case 'a':
       /* Listing option.  Just ignore these, we don't support additional
 	 ones.	*/
@@ -26877,6 +26900,11 @@ md_show_usage (FILE * fp)
 
   fprintf (fp, _("\
   --fix-v4bx              Allow BX in ARMv4 code\n"));
+
+#ifdef OBJ_ELF
+  fprintf (fp, _("\
+  --fdpic                 generate an FDPIC object file\n"));
+#endif /* OBJ_ELF */
 }
 
 #ifdef OBJ_ELF
diff --git a/include/ChangeLog b/include/ChangeLog
index 940136e..d159a25 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,8 @@
+2018-04-25  Christophe Lyon  <christophe.lyon@st.com>
+	Mickaël Guêné  <mickael.guene@st.com>
+
+	* elf/arm.h (EF_ARM_FDPIC): New.
+
 2018-04-18  Alan Modra  <amodra@gmail.com>
 
 	* coff/mipspe.h: Delete.
diff --git a/include/elf/common.h b/include/elf/common.h
index f435472..469fe5a 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -78,6 +78,7 @@
 
 #define ELFOSABI_C6000_ELFABI 64 /* Bare-metal TMS320C6000 */
 #define ELFOSABI_C6000_LINUX 65 /* Linux TMS320C6000 */
+#define ELFOSABI_ARM_FDPIC   65 /* ARM FDPIC */
 #define ELFOSABI_ARM	     97	/* ARM */
 #define ELFOSABI_STANDALONE 255	/* Standalone (embedded) application */