Make coff backend data read-only

The bfd_coff_backend_data struct should be read-only, the only thing
preventing this is that objcopy writes to one of the fields,
_bfd_coff_long_section_names.  This patch creates a copy of the field
in bfd coff_obj_tdata, which makes more sense anyway.  When enabling
long section names the intent is to do so for a particular bfd, not
for all bfds that might happen to be using the target xvec.

bfd/
	* coffcode.h: Update coff long section name comment.
	(bfd_coff_set_long_section_names_allowed): Use macro accessor
	to set flag.
	(bfd_coff_set_long_section_names_disallowed): Tidy.
	(coff_backend_info): Return a const pointer.
	(bfd_coff_std_swap_table, ticoff0_swap_table, ticoff1_swap_table),
	(bigobj_swap_table): Make const.
	(bfd_coff_long_section_names): Use tdata copy.
	(coff_mkobject): Set long_section_names from coff_backend_info.
	* coff-go32.c (_bfd_go32_mkobject): Likewise.
	* peicode.h (pe_mkobject): Likewise.
	* coff-sh.c (bfd_coff_small_swap_table): Make const.
	* libcoff-in.h (struct coff_tdata): Add long_section_names,
	reorder fields.
	* libcoff.h: Regenerate.
binutils/
	* objcopy.c (set_long_section_mode): Move earlier in file.
	(copy_object): Call set_long_section_mode here, after setting
	output format.
	(copy_file): Don't call set_long_section_mode.

6 files changed, 56 insertions, 34 deletions

diff --git a/bfd/coff-go32.c b/bfd/coff-go32.c
index 2088b2c..501f88f 100644
--- a/bfd/coff-go32.c
+++ b/bfd/coff-go32.c
@@ -80,6 +80,9 @@ _bfd_go32_mkobject (bfd * abfd)
 
   coff_data (abfd)->go32 = true;
 
+  bfd_coff_long_section_names (abfd)
+    = coff_backend_info (abfd)->_bfd_coff_long_section_names;
+
   return true;
 }
 
diff --git a/bfd/coff-sh.c b/bfd/coff-sh.c
index f043dc2..cc6faac 100644
--- a/bfd/coff-sh.c
+++ b/bfd/coff-sh.c
@@ -3079,7 +3079,7 @@ coff_small_new_section_hook (bfd *abfd, asection *section)
 /* This is copied from bfd_coff_std_swap_table so that we can change
    the default section alignment power.  */
 
-static bfd_coff_backend_data bfd_coff_small_swap_table =
+static const bfd_coff_backend_data bfd_coff_small_swap_table =
 {
   coff_swap_aux_in, coff_swap_sym_in, coff_swap_lineno_in,
   coff_swap_aux_out, coff_swap_sym_out,
diff --git a/bfd/coffcode.h b/bfd/coffcode.h
index 81d5cb0..e952bd7 100644
--- a/bfd/coffcode.h
+++ b/bfd/coffcode.h
@@ -134,9 +134,10 @@ SUBSUBSECTION
 	in output BFDs at runtime; if it is false, as it will be by default
 	when generating an executable image, long section names are truncated;
 	if true, the long section names extension is employed.  The hook
-	points to a function that allows the value of the flag to be altered
-	at runtime, on formats that support long section names at all; on
-	other formats it points to a stub that returns an error indication.
+	points to a function that allows the value of a copy of the flag
+	in coff object tdata to be altered at runtime, on formats that
+	support long section names at all; on other formats it points
+	to a stub that returns an error indication.
 
 	With input BFDs, the flag is set according to whether any long section
 	names are detected while reading the section headers.  For a completely
@@ -462,15 +463,14 @@ static bool ticoff1_bad_format_hook
 static bool
 bfd_coff_set_long_section_names_allowed (bfd *abfd, int enable)
 {
-  coff_backend_info (abfd)->_bfd_coff_long_section_names = enable;
+  bfd_coff_long_section_names (abfd) = enable;
   return true;
 }
 #else /* !defined (COFF_LONG_SECTION_NAMES) */
 static bool
-bfd_coff_set_long_section_names_disallowed (bfd *abfd, int enable)
+bfd_coff_set_long_section_names_disallowed (bfd *abfd ATTRIBUTE_UNUSED,
+					    int enable ATTRIBUTE_UNUSED)
 {
-  (void) abfd;
-  (void) enable;
   return false;
 }
 #endif /* defined (COFF_LONG_SECTION_NAMES) */
@@ -1541,7 +1541,7 @@ Special entry points for gdb to swap in coff symbol table parts:
 .} bfd_coff_backend_data;
 .
 .#define coff_backend_info(abfd) \
-.  ((bfd_coff_backend_data *) (abfd)->xvec->backend_data)
+.  ((const bfd_coff_backend_data *) (abfd)->xvec->backend_data)
 .
 .#define bfd_coff_swap_aux_in(a,e,t,c,ind,num,i) \
 .  ((coff_backend_info (a)->_bfd_coff_swap_aux_in) (a,e,t,c,ind,num,i))
@@ -1584,7 +1584,7 @@ Special entry points for gdb to swap in coff symbol table parts:
 .#define bfd_coff_long_filenames(abfd) \
 .  (coff_backend_info (abfd)->_bfd_coff_long_filenames)
 .#define bfd_coff_long_section_names(abfd) \
-.  (coff_backend_info (abfd)->_bfd_coff_long_section_names)
+.  (coff_data (abfd)->long_section_names)
 .#define bfd_coff_set_long_section_names(abfd, enable) \
 .  ((coff_backend_info (abfd)->_bfd_coff_set_long_section_names) (abfd, enable))
 .#define bfd_coff_default_section_alignment_power(abfd) \
@@ -2067,6 +2067,9 @@ coff_mkobject (bfd * abfd)
   coff->relocbase = 0;
   coff->local_toc_sym_map = 0;
 
+  bfd_coff_long_section_names (abfd)
+    = coff_backend_info (abfd)->_bfd_coff_long_section_names;
+
 /*  make_abs_section(abfd);*/
 
   return true;
@@ -5445,7 +5448,7 @@ coff_final_link_postscript (bfd * abfd ATTRIBUTE_UNUSED,
 #define coff_SWAP_scnhdr_in coff_swap_scnhdr_in
 #endif
 
-static bfd_coff_backend_data bfd_coff_std_swap_table ATTRIBUTE_UNUSED =
+static const bfd_coff_backend_data bfd_coff_std_swap_table ATTRIBUTE_UNUSED =
 {
   coff_SWAP_aux_in, coff_SWAP_sym_in, coff_SWAP_lineno_in,
   coff_SWAP_aux_out, coff_SWAP_sym_out,
@@ -5486,7 +5489,7 @@ static bfd_coff_backend_data bfd_coff_std_swap_table ATTRIBUTE_UNUSED =
 #ifdef TICOFF
 /* COFF0 differs in file/section header size and relocation entry size.  */
 
-static bfd_coff_backend_data ticoff0_swap_table =
+static const bfd_coff_backend_data ticoff0_swap_table =
 {
   coff_SWAP_aux_in, coff_SWAP_sym_in, coff_SWAP_lineno_in,
   coff_SWAP_aux_out, coff_SWAP_sym_out,
@@ -5528,7 +5531,7 @@ static bfd_coff_backend_data ticoff0_swap_table =
 #ifdef TICOFF
 /* COFF1 differs in section header size.  */
 
-static bfd_coff_backend_data ticoff1_swap_table =
+static const bfd_coff_backend_data ticoff1_swap_table =
 {
   coff_SWAP_aux_in, coff_SWAP_sym_in, coff_SWAP_lineno_in,
   coff_SWAP_aux_out, coff_SWAP_sym_out,
@@ -5789,7 +5792,7 @@ coff_bigobj_swap_aux_out (bfd * abfd,
   return AUXESZ;
 }
 
-static bfd_coff_backend_data bigobj_swap_table =
+static const bfd_coff_backend_data bigobj_swap_table =
 {
   coff_bigobj_swap_aux_in, coff_bigobj_swap_sym_in, coff_SWAP_lineno_in,
   coff_bigobj_swap_aux_out, coff_bigobj_swap_sym_out,
diff --git a/bfd/libcoff-in.h b/bfd/libcoff-in.h
index 8dec285..d27e5d4 100644
--- a/bfd/libcoff-in.h
+++ b/bfd/libcoff-in.h
@@ -79,21 +79,34 @@ typedef struct coff_tdata
   /* The unswapped external symbols.  May be NULL.  Read by
      _bfd_coff_get_external_symbols.  */
   void * external_syms;
-  /* If this is TRUE, the external_syms may not be freed.  */
-  bool keep_syms;
 
   /* The string table.  May be NULL.  Read by
      _bfd_coff_read_string_table.  */
   char *strings;
   /* The length of the strings table.  For error checking.  */
   bfd_size_type strings_len;
+
+  /* Set if long section names are supported.  A writable copy of the COFF
+     backend flag _bfd_coff_long_section_names.  */
+  bool long_section_names;
+
+  /* If this is TRUE, the external_syms may not be freed.  */
+  bool keep_syms;
   /* If this is TRUE, the strings may not be freed.  */
   bool keep_strings;
   /* If this is TRUE, the strings have been written out already.  */
   bool strings_written;
 
+  /* Is this a GO32 coff file?  */
+  bool go32;
+
   /* Is this a PE format coff file?  */
   int pe;
+
+  /* Copy of some of the f_flags bits in the COFF filehdr structure,
+     used by ARM code.  */
+  flagword flags;
+
   /* Used by the COFF backend linker.  */
   struct coff_link_hash_entry **sym_hashes;
 
@@ -111,13 +124,6 @@ typedef struct coff_tdata
   /* The timestamp from the COFF file header.  */
   long timestamp;
 
-  /* Copy of some of the f_flags bits in the COFF filehdr structure,
-     used by ARM code.  */
-  flagword flags;
-
-  /* Is this a GO32 coff file?  */
-  bool go32;
-
   /* A stub (extra data prepended before the COFF image) and its size.
      Used by coff-go32-exe, it contains executable data that loads the
      COFF object into memory.  */
diff --git a/bfd/libcoff.h b/bfd/libcoff.h
index 9d51cef..f03330f 100644
--- a/bfd/libcoff.h
+++ b/bfd/libcoff.h
@@ -83,21 +83,34 @@ typedef struct coff_tdata
   /* The unswapped external symbols.  May be NULL.  Read by
      _bfd_coff_get_external_symbols.  */
   void * external_syms;
-  /* If this is TRUE, the external_syms may not be freed.  */
-  bool keep_syms;
 
   /* The string table.  May be NULL.  Read by
      _bfd_coff_read_string_table.  */
   char *strings;
   /* The length of the strings table.  For error checking.  */
   bfd_size_type strings_len;
+
+  /* Set if long section names are supported.  A writable copy of the COFF
+     backend flag _bfd_coff_long_section_names.  */
+  bool long_section_names;
+
+  /* If this is TRUE, the external_syms may not be freed.  */
+  bool keep_syms;
   /* If this is TRUE, the strings may not be freed.  */
   bool keep_strings;
   /* If this is TRUE, the strings have been written out already.  */
   bool strings_written;
 
+  /* Is this a GO32 coff file?  */
+  bool go32;
+
   /* Is this a PE format coff file?  */
   int pe;
+
+  /* Copy of some of the f_flags bits in the COFF filehdr structure,
+     used by ARM code.  */
+  flagword flags;
+
   /* Used by the COFF backend linker.  */
   struct coff_link_hash_entry **sym_hashes;
 
@@ -115,13 +128,6 @@ typedef struct coff_tdata
   /* The timestamp from the COFF file header.  */
   long timestamp;
 
-  /* Copy of some of the f_flags bits in the COFF filehdr structure,
-     used by ARM code.  */
-  flagword flags;
-
-  /* Is this a GO32 coff file?  */
-  bool go32;
-
   /* A stub (extra data prepended before the COFF image) and its size.
      Used by coff-go32-exe, it contains executable data that loads the
      COFF object into memory.  */
@@ -841,7 +847,7 @@ typedef struct
 } bfd_coff_backend_data;
 
 #define coff_backend_info(abfd) \
-  ((bfd_coff_backend_data *) (abfd)->xvec->backend_data)
+  ((const bfd_coff_backend_data *) (abfd)->xvec->backend_data)
 
 #define bfd_coff_swap_aux_in(a,e,t,c,ind,num,i) \
   ((coff_backend_info (a)->_bfd_coff_swap_aux_in) (a,e,t,c,ind,num,i))
@@ -884,7 +890,7 @@ typedef struct
 #define bfd_coff_long_filenames(abfd) \
   (coff_backend_info (abfd)->_bfd_coff_long_filenames)
 #define bfd_coff_long_section_names(abfd) \
-  (coff_backend_info (abfd)->_bfd_coff_long_section_names)
+  (coff_data (abfd)->long_section_names)
 #define bfd_coff_set_long_section_names(abfd, enable) \
   ((coff_backend_info (abfd)->_bfd_coff_set_long_section_names) (abfd, enable))
 #define bfd_coff_default_section_alignment_power(abfd) \
diff --git a/bfd/peicode.h b/bfd/peicode.h
index 6b71f20..cc5a54e 100644
--- a/bfd/peicode.h
+++ b/bfd/peicode.h
@@ -292,6 +292,10 @@ pe_mkobject (bfd * abfd)
   pe->dos_message[15] = 0x0;
 
   memset (& pe->pe_opthdr, 0, sizeof pe->pe_opthdr);
+
+  bfd_coff_long_section_names (abfd)
+    = coff_backend_info (abfd)->_bfd_coff_long_section_names;
+
   return true;
 }