[PATCH v2] objcopy: Add elf header e_flags option in objcopy.

[liuzhensong <liuzhensong@loongson.cn>]

Specify flags when copying binary to elf file.
This flags will be written to the e_flags of the elf header.

usage:
  objcopy -I binary -O target --alt-elf-eflags=val bin_file  elf_file

binutils/
  * objcopy.c
  * doc/binutils.texi:Add the new objcopy option.
---
 binutils/doc/binutils.texi |  7 +++++++
 binutils/objcopy.c         | 16 ++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/binutils/doc/binutils.texi b/binutils/doc/binutils.texi
index 2c234c682aa..b36aad05c98 100644
--- a/binutils/doc/binutils.texi
+++ b/binutils/doc/binutils.texi
@@ -1302,6 +1302,7 @@ objcopy [@option{-F} @var{bfdname}|@option{--target=}@var{bfdname}]
         [@option{--weaken-symbols=}@var{filename}]
         [@option{--add-symbol} @var{name}=[@var{section}:]@var{value}[,@var{flags}]]
         [@option{--alt-machine-code=}@var{index}]
+        [@option{--alt-elf-eflags=}@var{value}]
         [@option{--prefix-symbols=}@var{string}]
         [@option{--prefix-sections=}@var{string}]
         [@option{--prefix-alloc-sections=}@var{string}]
@@ -1942,6 +1943,12 @@ being used.  For ELF based architectures if the @var{index}
 alternative does not exist then the value is treated as an absolute
 number to be stored in the e_machine field of the ELF header.
 
+@item --alt-elf-eflags=@var{value}
+If the output file has alternate ELF header e_flags, use the @var{vaule}
+instead of the default one.  This is useful in case objcopy a binary to
+an ELF to specify the e_flags. The value is treated as an absolute
+number to be stored in the e_flags field of the ELF header.
+
 @item --writable-text
 Mark the output text as writable.  This option isn't meaningful for all
 object file formats.
diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index 6fb31c8cac7..032caf565d1 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -303,6 +303,10 @@ enum long_section_name_handling
    This is also the only behaviour for 'strip'.  */
 static enum long_section_name_handling long_section_names = KEEP;
 
+/* Use alternative elf header e_flags?  */
+static bool alt_elf_eflags_set = false;
+static unsigned int alt_elf_eflags = 0;
+
 /* 150 isn't special; it's just an arbitrary non-ASCII char value.  */
 enum command_line_switch
 {
@@ -310,6 +314,7 @@ enum command_line_switch
   OPTION_ADD_GNU_DEBUGLINK,
   OPTION_ADD_SYMBOL,
   OPTION_ALT_MACH_CODE,
+  OPTION_ALT_ELF_EFLAGS,
   OPTION_CHANGE_ADDRESSES,
   OPTION_CHANGE_LEADING_CHAR,
   OPTION_CHANGE_SECTION_ADDRESS,
@@ -427,6 +432,7 @@ static struct option copy_options[] =
   {"adjust-vma", required_argument, 0, OPTION_CHANGE_ADDRESSES},
   {"adjust-warnings", no_argument, 0, OPTION_CHANGE_WARNINGS},
   {"alt-machine-code", required_argument, 0, OPTION_ALT_MACH_CODE},
+  {"alt-elf-eflags", required_argument, 0, OPTION_ALT_ELF_EFLAGS},
   {"binary-architecture", required_argument, 0, 'B'},
   {"byte", required_argument, 0, 'b'},
   {"change-addresses", required_argument, 0, OPTION_CHANGE_ADDRESSES},
@@ -660,6 +666,7 @@ copy_usage (FILE *stream, int exit_status)
      --weaken-symbols <file>       -W for all symbols listed in <file>\n\
      --add-symbol <name>=[<section>:]<value>[,<flags>]  Add a symbol\n\
      --alt-machine-code <index>    Use the target's <index>'th alternative machine\n\
+     --alt-elf-eflags=<value>      Use the alternative elf header e_flags\n\
      --writable-text               Mark the output text as writable\n\
      --readonly-text               Make the output text write protected\n\
      --pure                        Mark the output file as demand paged\n\
@@ -3496,6 +3503,10 @@ copy_object (bfd *ibfd, bfd *obfd, const bfd_arch_info_type *input_arch)
 	}
     }
 
+  if (bfd_get_flavour (obfd) == bfd_target_elf_flavour
+      && alt_elf_eflags_set)
+    elf_elfheader (obfd)->e_flags = alt_elf_eflags;
+
   return true;
 }
 
@@ -5863,6 +5874,11 @@ copy_main (int argc, char *argv[])
 	    fatal (_("verilog data width must be at least 1 byte"));
 	  break;
 
+	case OPTION_ALT_ELF_EFLAGS:
+	  alt_elf_eflags_set = true;
+	  alt_elf_eflags = parse_vma (optarg, "--alt-elf-eflags");
+	  break;
+
 	case 0:
 	  /* We've been given a long option.  */
 	  break;
-- 
2.31.1