* som.c (struct som_misc_symbol_info): Add is_comdat, is_common and

	dup_common fields.
	(setup_sections): Use som_subspace_dictionary_record struct instead
	subspace_dictionary_record.  Set SEC_LINK_ONCE if subspace is
	is_comdat, is_common or dup_common.
	(som_prep_headers): Use som_subspace_dictionary_record struct.  Set
	is_comdat, is_common and dup_common in section subspace_dict from
	copy_data.
	(som_begin_writing): Use som_subspace_dictionary_record struct.
	(som_finish_writing): Likewise.
	(som_bfd_derive_misc_symbol_info): Add support to set is_comdat,
	is_common and dup_common flags in info for symbol.  Add comment
	regarding linker support for these fields.  Slightly reorganize
	function.
	(som_build_and_write_symbol_table): Set is_comdat, is_common and
	dup_common fields in symbol table from symbol info.
	(bfd_som_set_subsection_attributes): Add comdat, common and dup_common
	arguments.  Set corresponding fields in copy_data.  Change all callers.
	(som_bfd_ar_write_symbol_stuff): Set dup_common flag in library
	symbol table.
	(som_vec): Add SEC_LINK_ONCE to applicable section flags.
	* som.h (som_subspace_dictionary_record): Define.
	(som_copyable_section_data_struct): Add is_comdat, is_common and
	dup_common fields.
	(som_section_data_struct): Use som_subspace_dictionary_record struct
	instead of subspace_dictionary_record.
	(bfd_boolean bfd_som_set_subsection_attributes): Adjust prototype.
	* config/obj-som.c (obj_som_init_stab_section): Add new arguments in
	call to obj_set_subsection_attributes.
	(obj_som_init_stab_section): Likewise.
	* config/tc-hppa.c (default_subspace_dict): Add comdat field.
	(pa_def_subspaces): Provide comdat default.
	(pa_subspace): Handle new "comdat" parameter.  Set SEC_LINK_ONCE and
	not SEC_IS_COMMON if section is comdat, common or dup_common.  Update
	calls to create_new_subspace and update_subspace to pass comdat flag.
	(create_new_subspace, update_subspace): Add new comdat argument.  Use
	it in calls to obj_set_subsection_attributes.
	* doc/c-hppa.texi (.subspa, .nsubspa): Document new comdat parameter
	and use of comdat, common and dup_comm parameters.

4 files changed, 103 insertions, 30 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 08a4750..23eee16 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,18 @@
+2004-04-28  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
+
+	* config/obj-som.c (obj_som_init_stab_section): Add new arguments in
+	call to obj_set_subsection_attributes.
+	(obj_som_init_stab_section): Likewise.
+	* config/tc-hppa.c (default_subspace_dict): Add comdat field.
+	(pa_def_subspaces): Provide comdat default.
+	(pa_subspace): Handle new "comdat" parameter.  Set SEC_LINK_ONCE and
+	not SEC_IS_COMMON if section is comdat, common or dup_common.  Update
+	calls to create_new_subspace and update_subspace to pass comdat flag.
+	(create_new_subspace, update_subspace): Add new comdat argument.  Use
+	it in calls to obj_set_subsection_attributes.
+	* doc/c-hppa.texi (.subspa, .nsubspa): Document new comdat parameter
+	and use of comdat, common and dup_comm parameters.
+
 2004-04-26  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/obj-elf.c (obj_elf_change_section): Check if the old
diff --git a/gas/config/obj-som.c b/gas/config/obj-som.c
index 454042a..a736c96 100644
--- a/gas/config/obj-som.c
+++ b/gas/config/obj-som.c
@@ -248,7 +248,7 @@ obj_som_init_stab_section (seg)
      (just created above).  Also set some attributes which BFD does
      not understand.  In particular, access bits, sort keys, and load
      quadrant.  */
-  obj_set_subsection_attributes (seg, space, 0x1f, 73, 0);
+  obj_set_subsection_attributes (seg, space, 0x1f, 73, 0, 0, 0, 0);
   bfd_set_section_alignment (stdoutput, seg, 2);
 
   /* Make some space for the first special stab entry and zero the memory.
@@ -271,7 +271,7 @@ obj_som_init_stab_section (seg)
      not understand.  In particular, access bits, sort keys, and load
      quadrant.  */
   seg = bfd_get_section_by_name (stdoutput, "$GDB_STRINGS$");
-  obj_set_subsection_attributes (seg, space, 0x1f, 72, 0);
+  obj_set_subsection_attributes (seg, space, 0x1f, 72, 0, 0, 0, 0);
   bfd_set_section_alignment (stdoutput, seg, 2);
 
   subseg_set (saved_seg, saved_subseg);
diff --git a/gas/config/tc-hppa.c b/gas/config/tc-hppa.c
index 77563a9..72abe1d 100644
--- a/gas/config/tc-hppa.c
+++ b/gas/config/tc-hppa.c
@@ -363,6 +363,9 @@ struct default_subspace_dict
     /* Nonzero if this subspace contains only code.  */
     char code_only;
 
+    /* Nonzero if this is a comdat subspace.  */
+    char comdat;
+
     /* Nonzero if this is a common subspace.  */
     char common;
 
@@ -555,13 +558,13 @@ static sd_chain_struct *create_new_space PARAMS ((char *, int, int,
 						  asection *, int));
 static ssd_chain_struct *create_new_subspace PARAMS ((sd_chain_struct *,
 						      char *, int, int,
-						      int, int, int,
+						      int, int, int, int,
 						      int, int, int, int,
 						      int, asection *));
 static ssd_chain_struct *update_subspace PARAMS ((sd_chain_struct *,
 						  char *, int, int, int,
 						  int, int, int, int,
-						  int, int, int,
+						  int, int, int, int,
 						  asection *));
 static sd_chain_struct *is_defined_space PARAMS ((char *));
 static ssd_chain_struct *is_defined_subspace PARAMS ((char *));
@@ -1117,12 +1120,12 @@ static const struct selector_entry selector_table[] =
 
 static struct default_subspace_dict pa_def_subspaces[] =
 {
-  {"$CODE$", 1, 1, 1, 0, 0, 0, 24, 0x2c, 0, 8, 0, 0, SUBSEG_CODE},
-  {"$DATA$", 1, 1, 0, 0, 0, 0, 24, 0x1f, 1, 8, 1, 1, SUBSEG_DATA},
-  {"$LIT$", 1, 1, 0, 0, 0, 0, 16, 0x2c, 0, 8, 0, 0, SUBSEG_LIT},
-  {"$MILLICODE$", 1, 1, 0, 0, 0, 0, 8, 0x2c, 0, 8, 0, 0, SUBSEG_MILLI},
-  {"$BSS$", 1, 1, 0, 0, 0, 1, 80, 0x1f, 1, 8, 1, 1, SUBSEG_BSS},
-  {NULL, 0, 1, 0, 0, 0, 0, 255, 0x1f, 0, 4, 0, 0, 0}
+  {"$CODE$", 1, 1, 1, 0, 0, 0, 0, 24, 0x2c, 0, 8, 0, 0, SUBSEG_CODE},
+  {"$DATA$", 1, 1, 0, 0, 0, 0, 0, 24, 0x1f, 1, 8, 1, 1, SUBSEG_DATA},
+  {"$LIT$", 1, 1, 0, 0, 0, 0, 0, 16, 0x2c, 0, 8, 0, 0, SUBSEG_LIT},
+  {"$MILLICODE$", 1, 1, 0, 0, 0, 0, 0, 8, 0x2c, 0, 8, 0, 0, SUBSEG_MILLI},
+  {"$BSS$", 1, 1, 0, 0, 0, 0, 1, 80, 0x1f, 1, 8, 1, 1, SUBSEG_BSS},
+  {NULL, 0, 1, 0, 0, 0, 0, 0, 255, 0x1f, 0, 4, 0, 0, 0}
 };
 
 static struct default_space_dict pa_def_spaces[] =
@@ -7454,7 +7457,7 @@ pa_subspace (create_new)
      int create_new;
 {
   char *name, *ss_name, c;
-  char loadable, code_only, common, dup_common, zero, sort;
+  char loadable, code_only, comdat, common, dup_common, zero, sort;
   int i, access, space_index, alignment, quadrant, applicable, flags;
   sd_chain_struct *space;
   ssd_chain_struct *ssd;
@@ -7480,6 +7483,7 @@ pa_subspace (create_new)
       sort = 0;
       access = 0x7f;
       loadable = 1;
+      comdat = 0;
       common = 0;
       dup_common = 0;
       code_only = 0;
@@ -7514,6 +7518,7 @@ pa_subspace (create_new)
 	      if (strcasecmp (pa_def_subspaces[i].name, ss_name) == 0)
 		{
 		  loadable = pa_def_subspaces[i].loadable;
+		  comdat = pa_def_subspaces[i].comdat;
 		  common = pa_def_subspaces[i].common;
 		  dup_common = pa_def_subspaces[i].dup_common;
 		  code_only = pa_def_subspaces[i].code_only;
@@ -7577,6 +7582,11 @@ pa_subspace (create_new)
 		  *input_line_pointer = c;
 		  loadable = 0;
 		}
+	      else if ((strncasecmp (name, "comdat", 6) == 0))
+		{
+		  *input_line_pointer = c;
+		  comdat = 1;
+		}
 	      else if ((strncasecmp (name, "common", 6) == 0))
 		{
 		  *input_line_pointer = c;
@@ -7609,8 +7619,17 @@ pa_subspace (create_new)
 	flags |= (SEC_ALLOC | SEC_LOAD);
       if (code_only)
 	flags |= SEC_CODE;
-      if (common || dup_common)
-	flags |= SEC_IS_COMMON;
+
+      /* These flags are used to implement various flavors of initialized
+	 common.  The SOM linker discards duplicate subspaces when they
+	 have the same "key" symbol name.  This support is more like
+	 GNU linkonce than BFD common.  Further, pc-relative relocations
+	 are converted to section relative relocations in BFD common
+	 sections.  This complicates the handling of relocations in
+	 common sections containing text and isn't currently supported
+	 correctly in the SOM BFD backend.  */
+      if (comdat || common || dup_common)
+	flags |= SEC_LINK_ONCE;
 
       flags |= SEC_RELOC | SEC_HAS_CONTENTS;
 
@@ -7652,16 +7671,16 @@ pa_subspace (create_new)
       if (ssd)
 
 	current_subspace = update_subspace (space, ss_name, loadable,
-					    code_only, common, dup_common,
-					    sort, zero, access, space_index,
-					    alignment, quadrant,
+					    code_only, comdat, common,
+					    dup_common, sort, zero, access,
+					    space_index, alignment, quadrant,
 					    section);
       else
 	current_subspace = create_new_subspace (space, ss_name, loadable,
-						code_only, common,
+						code_only, comdat, common,
 						dup_common, zero, sort,
 						access, space_index,
-					      alignment, quadrant, section);
+						alignment, quadrant, section);
 
       demand_empty_rest_of_line ();
       current_subspace->ssd_seg = section;
@@ -7782,6 +7801,7 @@ pa_spaces_begin ()
       create_new_subspace (space, name,
 			   pa_def_subspaces[i].loadable,
 			   pa_def_subspaces[i].code_only,
+			   pa_def_subspaces[i].comdat,
 			   pa_def_subspaces[i].common,
 			   pa_def_subspaces[i].dup_common,
 			   pa_def_subspaces[i].zero,
@@ -7883,12 +7903,12 @@ create_new_space (name, spnum, loadable, defined, private,
    order as defined by the SORT entries.  */
 
 static ssd_chain_struct *
-create_new_subspace (space, name, loadable, code_only, common,
+create_new_subspace (space, name, loadable, code_only, comdat, common,
 		     dup_common, is_zero, sort, access, space_index,
 		     alignment, quadrant, seg)
      sd_chain_struct *space;
      char *name;
-     int loadable, code_only, common, dup_common, is_zero;
+     int loadable, code_only, comdat, common, dup_common, is_zero;
      int sort;
      int access;
      int space_index;
@@ -7945,8 +7965,8 @@ create_new_subspace (space, name, loadable, code_only, common,
     }
 
 #ifdef obj_set_subsection_attributes
-  obj_set_subsection_attributes (seg, space->sd_seg, access,
-				 sort, quadrant);
+  obj_set_subsection_attributes (seg, space->sd_seg, access, sort,
+				 quadrant, comdat, common, dup_common);
 #endif
 
   return chain_entry;
@@ -7956,12 +7976,13 @@ create_new_subspace (space, name, loadable, code_only, common,
    various arguments.   Return the modified subspace chain entry.  */
 
 static ssd_chain_struct *
-update_subspace (space, name, loadable, code_only, common, dup_common, sort,
-		 zero, access, space_index, alignment, quadrant, section)
+update_subspace (space, name, loadable, code_only, comdat, common, dup_common,
+		 sort, zero, access, space_index, alignment, quadrant, section)
      sd_chain_struct *space;
      char *name;
      int loadable;
      int code_only;
+     int comdat;
      int common;
      int dup_common;
      int zero;
@@ -7977,8 +7998,8 @@ update_subspace (space, name, loadable, code_only, common, dup_common, sort,
   chain_entry = is_defined_subspace (name);
 
 #ifdef obj_set_subsection_attributes
-  obj_set_subsection_attributes (section, space->sd_seg, access,
-				 sort, quadrant);
+  obj_set_subsection_attributes (section, space->sd_seg, access, sort,
+				 quadrant, comdat, common, dup_common);
 #endif
 
   return chain_entry;
diff --git a/gas/doc/c-hppa.texi b/gas/doc/c-hppa.texi
index 7e9ea30..9970188 100644
--- a/gas/doc/c-hppa.texi
+++ b/gas/doc/c-hppa.texi
@@ -245,14 +245,51 @@ identified by keywords.  The keywords recognized are @samp{quad=@var{expr}}
 beginning of this subsection; a power of two), @samp{access=@var{expr}} (value
 for ``access rights'' field), @samp{sort=@var{expr}} (sorting order for this
 subspace in link), @samp{code_only} (subsection contains only code),
-@samp{unloadable} (subsection cannot be loaded into memory), @samp{common}
-(subsection is common block), @samp{dup_comm} (initialized data may have
-duplicate names), or @samp{zero} (subsection is all zeros, do not write in
-object file).
+@samp{unloadable} (subsection cannot be loaded into memory), @samp{comdat}
+(subsection is comdat), @samp{common} (subsection is common block),
+@samp{dup_comm} (subsection may have duplicate names), or @samp{zero}
+(subsection is all zeros, do not write in object file).
 
 @code{.nsubspa} always creates a new subspace with the given name, even
 if one with the same name already exists.
 
+@samp{comdat}, @samp{common} and @samp{dup_comm} can be used to implement
+various flavors of one-only support when using the SOM linker.  The SOM
+linker only supports specific combinations of these flags.  The details
+are not documented.  A brief description is provided here.
+
+@samp{comdat} provides a form of linkonce support.  It is useful for
+both code and data subspaces.  A @samp{comdat} subspace has a key symbol
+marked by the @samp{is_comdat} flag or @samp{ST_COMDAT}.  Only the first
+subspace for any given key is selected.  The key symbol becomes universal
+in shared links.  This is similar to the behavior of @samp{secondary_def}
+symbols.
+
+@samp{common} provides Fortran named common support.  It is only useful
+for data subspaces.  Symbols with the flag @samp{is_common} retain this
+flag in shared links.  Referencing a @samp{is_common} symbol in a shared
+library from outside the library doesn't work.  Thus, @samp{is_common}
+symbols must be output whenever they are needed.
+
+@samp{common} and @samp{dup_comm} together provide Cobol common support.
+The subspaces in this case must all be the same length.  Otherwise, this
+support is similar to the Fortran common support.
+
+@samp{dup_comm} by itself provides a type of one-only support for code.
+Only the first @samp{dup_comm} subspace is selected.  There is a rather
+complex algorithm to compare subspaces.  Code symbols marked with the
+@samp{dup_common} flag are hidden.  This support was intended for "C++
+duplicate inlines".
+
+A simplified technique is used to mark the flags of symbols based on
+the flags of their subspace.  A symbol with the scope SS_UNIVERSAL and
+type ST_ENTRY, ST_CODE or ST_DATA is marked with the corresponding
+settings of @samp{comdat}, @samp{common} and @samp{dup_comm} from the
+subspace, respectively.  This avoids having to introduce additional
+directives to mark these symbols.  The HP assembler sets @samp{is_common}
+from @samp{common}.  However, it doesn't set the @samp{dup_common} from
+@samp{dup_comm}.  It doesn't have @samp{comdat} support.
+
 @item .version "@var{str}"
 Write @var{str} as version identifier in object code.
 @end table