optionally postpone assignment of Common

[John Reiser <jreiser@BitWagon.com>]

This patch against today's CVS add a new commandline option
--no-define-common and corresponding script command
INHIBIT_COMMON_ALLOCATION, which postpone the assignment of
addresses for Common symbols.  Tested on i386.

If a Common block is left "dangling" (no allocation in some
other module before runtime) then some existing rtld
(such as Linux /lib/ld-2.1.3.so) allocate it in .text,
but that is a problem that is outside of binutils.


Index: ChangeLog
===================================================================
RCS file: /cvs/src/src/ld/ChangeLog,v
retrieving revision 1.490
diff -u -r1.490 ChangeLog
--- ChangeLog	2001/09/24 21:16:47	1.490
+++ ChangeLog	2001/09/25 18:38:07
@@ -1,3 +1,13 @@
+2001-09-25  John Reiser  <jreiser@BitWagon.com>
+
+	* ldlang.c(lang_common): Conditionally inhibit Common allocation.
+	* lexsup.c: Add --no-define-common commandline option.
+	* ldgram.y: Add INHIBIT_COMMON_ALLOCATION script command.
+	* ldlex.l: Likewise.
+	* ld.h: Add command_line.inhibit_common_definition .
+	* ldmain.c(main): Initialize.
+	* ld.texinfo: Document.
+	
 2001-09-24  Charles Wilson  <cwilson@ece.gatech.edu>
 
 	* pe-dll.c: Remove obsoleted declaration of
Index: ld.h
===================================================================
RCS file: /cvs/src/src/ld/ld.h,v
retrieving revision 1.14
diff -u -r1.14 ld.h
--- ld.h	2001/08/12 07:59:28	1.14
+++ ld.h	2001/09/25 18:30:49
@@ -102,6 +102,9 @@
 typedef struct {
   /* 1 => assign space to common symbols even if `relocatable_output'.  */
   boolean force_common_definition;
+
+  /* 1 => do not assign addresses to common symbols. */
+  boolean inhibit_common_definition;
   boolean relax;
 
   /* Name of runtime interpreter to invoke.  */
Index: ld.texinfo
===================================================================
RCS file: /cvs/src/src/ld/ld.texinfo,v
retrieving revision 1.51
diff -u -r1.51 ld.texinfo
--- ld.texinfo	2001/09/24 18:35:08	1.51
+++ ld.texinfo	2001/09/25 18:30:56
@@ -950,6 +950,13 @@
 symbol is defined, the first file listed is the location of the
 definition.  The remaining files contain references to the symbol.
 
+@cindex common allocation
+@kindex --no-define-common
+@item --no-define-common
+This option inhibits the assignment of addresses to common symbols.
+The script command @code{INHIBIT_COMMON_ALLOCATION} has the same effect.
+@xref{Miscellaneous Commands}.
+
 @cindex symbols, from command line
 @kindex --defsym @var{symbol}=@var{exp}
 @item --defsym @var{symbol}=@var{expression}
@@ -2310,6 +2317,13 @@
 This command has the same effect as the @samp{-d} command-line option:
 to make @code{ld} assign space to common symbols even if a relocatable
 output file is specified (@samp{-r}).
+
+@item INHIBIT_COMMON_ALLOCATION
+@kindex INHIBIT_COMMON_ALLOCATION
+@cindex common allocation in linker script
+This command has the same effect as the @samp{--no-define-common}
+command-line option: to make @code{ld} omit the assignment of addresses
+to common symbols even for a non-relocatable output file.
 
 @item NOCROSSREFS(@var{section} @var{section} @dots{})
 @kindex NOCROSSREFS(@var{sections})
Index: ldgram.y
===================================================================
RCS file: /cvs/src/src/ld/ldgram.y,v
retrieving revision 1.13
diff -u -r1.13 ldgram.y
--- ldgram.y	2001/08/15 17:10:18	1.13
+++ ldgram.y	2001/09/25 18:30:57
@@ -125,6 +125,7 @@
 %token SECTIONS PHDRS SORT
 %token '{' '}'
 %token SIZEOF_HEADERS OUTPUT_FORMAT FORCE_COMMON_ALLOCATION OUTPUT_ARCH
+%token INHIBIT_COMMON_ALLOCATION
 %token SIZEOF_HEADERS
 %token INCLUDE
 %token MEMORY DEFSYMEND
@@ -321,6 +322,8 @@
 		  { ldfile_set_output_arch($3); }
 	|	FORCE_COMMON_ALLOCATION
 		{ command_line.force_common_definition = true ; }
+	|	INHIBIT_COMMON_ALLOCATION
+		{ command_line.inhibit_common_definition = true ; }
 	|	INPUT '(' input_list ')'
 	|	GROUP
 		  { lang_enter_group (); }
Index: ldlang.c
===================================================================
RCS file: /cvs/src/src/ld/ldlang.c,v
retrieving revision 1.62
diff -u -r1.62 ldlang.c
--- ldlang.c	2001/09/19 05:33:33	1.62
+++ ldlang.c	2001/09/25 18:31:01
@@ -3553,6 +3553,8 @@
 static void
 lang_common ()
 {
+  if (command_line.inhibit_common_definition)
+    return;
   if (link_info.relocateable
       && ! command_line.force_common_definition)
     return;
Index: ldlex.l
===================================================================
RCS file: /cvs/src/src/ld/ldlex.l,v
retrieving revision 1.6
diff -u -r1.6 ldlex.l
--- ldlex.l	2001/09/19 05:33:33	1.6
+++ ldlex.l	2001/09/25 18:31:02
@@ -260,6 +260,7 @@
 <BOTH,SCRIPT>"CREATE_OBJECT_SYMBOLS"	{ RTOKEN(CREATE_OBJECT_SYMBOLS);}
 <BOTH,SCRIPT>"CONSTRUCTORS"		{ RTOKEN( CONSTRUCTORS);}
 <BOTH,SCRIPT>"FORCE_COMMON_ALLOCATION" { RTOKEN(FORCE_COMMON_ALLOCATION);}
+<BOTH,SCRIPT>"INHIBIT_COMMON_ALLOCATION" { RTOKEN(INHIBIT_COMMON_ALLOCATION);}
 <BOTH,SCRIPT>"SECTIONS"		{ RTOKEN(SECTIONS);}
 <BOTH,SCRIPT>"FILL"			{ RTOKEN(FILL);}
 <BOTH,SCRIPT>"STARTUP"		{ RTOKEN(STARTUP);}
Index: ldmain.c
===================================================================
RCS file: /cvs/src/src/ld/ldmain.c,v
retrieving revision 1.34
diff -u -r1.34 ldmain.c
--- ldmain.c	2001/09/19 05:33:33	1.34
+++ ldmain.c	2001/09/25 18:31:03
@@ -205,6 +205,7 @@
   config.split_by_reloc = (unsigned) -1;
   config.split_by_file = (bfd_size_type) -1;
   command_line.force_common_definition = false;
+  command_line.inhibit_common_definition = false;
   command_line.interpreter = NULL;
   command_line.rpath = NULL;
   command_line.warn_mismatch = true;
Index: lexsup.c
===================================================================
RCS file: /cvs/src/src/ld/lexsup.c,v
retrieving revision 1.40
diff -u -r1.40 lexsup.c
--- lexsup.c	2001/09/19 05:33:33	1.40
+++ lexsup.c	2001/09/25 18:31:05
@@ -132,6 +132,7 @@
 #define OPTION_ALLOW_SHLIB_UNDEFINED	(OPTION_TARGET_HELP + 1)
 #define OPTION_DISCARD_NONE		(OPTION_ALLOW_SHLIB_UNDEFINED + 1)
 #define OPTION_SPARE_DYNAMIC_TAGS	(OPTION_DISCARD_NONE + 1)
+#define OPTION_NO_DEFINE_COMMON		(OPTION_SPARE_DYNAMIC_TAGS + 1)
 
 /* The long options.  This structure is used for both the option
    parsing and the help text.  */
@@ -311,6 +312,8 @@
      '\0', N_("SYMBOL"), N_("Call SYMBOL at load-time"), ONE_DASH },
   { {"Map", required_argument, NULL, OPTION_MAP},
       '\0', N_("FILE"), N_("Write a map file"), ONE_DASH },
+  { {"no-define-common", no_argument, NULL, OPTION_NO_DEFINE_COMMON},
+      '\0', NULL, N_("Do not define Common storage"), TWO_DASHES },
   { {"no-demangle", no_argument, NULL, OPTION_NO_DEMANGLE },
       '\0', NULL, N_("Do not demangle symbol names"), TWO_DASHES },
   { {"no-keep-memory", no_argument, NULL, OPTION_NO_KEEP_MEMORY},
@@ -746,6 +749,9 @@
 	case 'n':
 	  config.magic_demand_paged = false;
 	  config.dynamic_link = false;
+	  break;
+	case OPTION_NO_DEFINE_COMMON:
+	  command_line.inhibit_common_definition = true;
 	  break;
 	case OPTION_NO_DEMANGLE:
 	  demangling = false;

-- 
John Reiser, jreiser@BitWagon.com