Patch to "generalize" setting section start addresses via command line

[Thomas de Lellis <tdel at windriver dot com>]

Patch to "generalize" setting of section start addresses
via the command line.

The GNU ld linker only allows -T with the
.text, .data, and .bss sections via the command line
options:

-Ttext org
-Tdata org
-Tbss org

The gnu linker is also quirky in that -T is used for both
section start addresses and using external linker command files.
If you use -T with ANY other name besides text/data/bss, it
assumes it's looking for an external linker command script.

We needed a simple way to set start adresses of other sections
from the command line, but, we also use -T for external linker
scripts so wanted to preserve all the present ld behavior. We
ended up adding a new command line option:

--section-start sectionname=org

sectionname can be any section instead of just .text/.data/.bss
and you must include all the characters (.) in your section
names... (the syntax is like that of -defsym)

--section-start .mysection=0x20000

:
:

-Ttext 0x1234 translates to --section-start .text=0x1234

=======================================================================
ld/ChangeLog
2000-05-15  Thomas de Lellis  <tdel@windriver.com>

        * ld.1: added documentation for new command line option
        --section-start sectionname=sectionorg
        This is a generic version of -Ttext etc. which accepts
        any section name as a parameter instead of just
        text/data/bss.
        * ld.texinfo: more docs.
        * ldgram.y: add code for processing of --section-start option
        * ldlex.h: ditto.
        * ldlex.l: ditto.
        * ldlexsup: (parse_args): recognize new command line option.
        
=======================================================================
*** ld.1	Thu May 18 18:13:24 2000
--- ld.1.new	Thu May 18 18:27:00 2000
*************** ld \- the GNU linker
*** 122,127 ****
--- 122,133 ----
  .RB "[\|" "\-T\ "\c
  .I commandfile\c
  \&\|]  
+ .br
+ .RB "[\|" "\-\-section\-start\ "\c
+ .I sectionname\c
+ \& = \c
+ .I sectionorg\c
+ \&\|]
  .RB "[\|" "\-Ttext\ "\c
  .I textorg\c
  \&\|] 
*************** The exceptions\(em\&which may meaningful
*** 253,260 ****
  .B \-format\c
  \&), \c
  .B \-defsym\c
! \&,
! \c
  .B \-L\c
  \&, \c
  .B \-l\c
--- 259,267 ----
  .B \-format\c
  \&), \c
  .B \-defsym\c
! \&, \c
! .B \-\-section\-start\c
! \&, \c
  .B \-L\c
  \&, \c
  .B \-l\c
*************** relocations one output section will cont
*** 888,893 ****
--- 895,919 ----
  Similar to
  .B \-split\-by\-reloc
  but creates a new output section for each input file.
+ 
+ .TP
+ .BI "--section-start " "sectionname" "\fR = \fP" expression
+ Locate a section in the output file at the absolute
+ address given by \c
+ .I expression\c
+ \&.  You may use this option as many
+ times as necessary to locate multiple sections in the command line.  A
+ limited form of arithmetic is supported for the \c
+ .I expression\c
+ \& in this
+ context: you may give a hexadecimal constant or the name of an existing
+ symbol, or use \c
+ .B +\c
+ \& and \c
+ .B \-\c
+ \& to add or subtract hexadecimal
+ constants or symbols.  If you need more elaborate expressions, consider
+ using the linker command language from a script.
  
  .TP
  .BI "\-Tbss " "org"\c
=======================================================================
*** ld/ld.texinfo	Fri May 19 11:02:15 2000
--- newld/ld.texinfo	Fri May 19 11:16:15 2000
*************** full debugging information by over 30 pe
*** 1143,1148 ****
--- 1143,1162 ----
  trouble).  The @samp{--traditional-format} switch tells @code{ld} to not
  combine duplicate entries.
  
+ @kindex --section-start @var{sectionname}=@var{exp}
+ @item --section-start @var{sectionname}=@var{expression}
+ Locate a section in the output file at the absolute
+ address given by @var{expression}.  You may use this option as many
+ times as necessary to locate multiple sections in the command line.  A
+ limited form of arithmetic is supported for the @var{expression} in this
+ context: you may give a hexadecimal constant or the name of an existing
+ symbol, or use @code{+} and @code{-} to add or subtract hexadecimal
+ constants or symbols.  If you need more elaborate expressions, consider
+ using the linker command language from a script (@pxref{Assignments,,
+ Assignment: Symbol Definitions}).  @emph{Note:} there should be no white
+ space between @var{symbol}, the equals sign (``@key{=}''), and
+ @var{expression}.
+ 
  @kindex -Tbss @var{org}
  @kindex -Tdata @var{org}
  @kindex -Ttext @var{org}
=======================================================================
*** ld/ldgram.y	Fri May 19 11:02:16 2000
--- newld/ldgram.y	Fri May 19 13:24:17 2000
*************** static int error_index;
*** 144,149 ****
--- 144,150 ----
  %token GLOBAL LOCAL VERSIONK INPUT_VERSION_SCRIPT
  %token KEEP
  %token EXCLUDE_FILE
+ %token INPUT_SECTION_START 
  %type <versyms> vers_defns
  %type <versnode> vers_tag
  %type <deflist> verdep
*************** file:	
*** 155,160 ****
--- 156,162 ----
  	|	INPUT_MRI_SCRIPT mri_script_file
  	|	INPUT_VERSION_SCRIPT version_script_file
  	|	INPUT_DEFSYM defsym_expr
+ 	|	INPUT_SECTION_START section_start_expr
  	;
  
  
*************** defsym_expr:
*** 167,172 ****
--- 169,182 ----
  		{
  		  ldlex_popstate();
  		  lang_add_assignment(exp_assop($3,$2,$4));
+ 		}
+ 
+ section_start_expr:
+ 		{ ldlex_section_start(); }
+ 		NAME '=' exp
+ 		{
+ 		  ldlex_popstate();
+ 		  lang_section_start($2,$4);
  		}
  
  /* SYNTAX WITHIN AN MRI SCRIPT FILE */  
=======================================================================
*** ld/ldlex.h	Fri May 19 11:02:19 2000
--- newld/ldlex.h	Fri May 19 13:27:55 2000
*************** typedef enum input_enum {
*** 29,35 ****
    input_script,
    input_mri_script,
    input_version_script,
!   input_defsym
  } input_type;
  
  extern input_type parser_input;
--- 29,36 ----
    input_script,
    input_mri_script,
    input_version_script,
!   input_defsym,
!   input_section_start
  } input_type;
  
  extern input_type parser_input;
*************** extern void ldlex_mri_script PARAMS ((vo
*** 46,51 ****
--- 47,53 ----
  extern void ldlex_version_script PARAMS ((void));
  extern void ldlex_version_file PARAMS ((void));
  extern void ldlex_defsym PARAMS ((void));
+ extern void ldlex_section_start PARAMS ((void));
  extern void ldlex_expression PARAMS ((void));
  extern void ldlex_both PARAMS ((void));
  extern void ldlex_command PARAMS ((void));
=======================================================================
*** ld/ldlex.l	Fri May 19 11:02:19 2000
--- newld/ldlex.l	Fri May 19 13:41:20 2000
*************** static void lex_warn_invalid PARAMS ((ch
*** 87,93 ****
  	EXPRESSION	definitely in an expression
  	SCRIPT		definitely in a script
  	BOTH		either EXPRESSION or SCRIPT
! 	DEFSYMEXP	in an argument to -defsym
          MRI             in an MRI script
  	VERS_START	starting a Sun style mapfile
  	VERS_SCRIPT	a Sun style mapfile
--- 87,93 ----
  	EXPRESSION	definitely in an expression
  	SCRIPT		definitely in a script
  	BOTH		either EXPRESSION or SCRIPT
! 	DEFSYMEXP	in an argument to -defsym or --start-section
          MRI             in an MRI script
  	VERS_START	starting a Sun style mapfile
  	VERS_SCRIPT	a Sun style mapfile
*************** V_IDENTIFIER [*?.$_a-zA-Z][*?.$_a-zA-Z0-
*** 138,143 ****
--- 138,144 ----
  	case input_mri_script: return INPUT_MRI_SCRIPT; break;
  	case input_version_script: return INPUT_VERSION_SCRIPT; break;
  	case input_defsym: return INPUT_DEFSYM; break;
+ 	case input_section_start: return INPUT_SECTION_START; break;
  	default: abort ();
  	}
      }
*************** ldlex_version_file ()
*** 549,554 ****
--- 550,562 ----
  
  void
  ldlex_defsym ()
+ {
+   *(state_stack_p)++ = yy_start;
+   BEGIN (DEFSYMEXP);
+ }
+ 	   
+ void
+ ldlex_section_start ()
  {
    *(state_stack_p)++ = yy_start;
    BEGIN (DEFSYMEXP);
=======================================================================
*** ld/lexsup.c	Fri May 19 11:02:20 2000
--- newld/lexsup.c	Fri May 19 13:54:38 2000
*************** int parsing_defsym = 0;
*** 123,128 ****
--- 123,129 ----
  #define OPTION_NO_UNDEFINED		(OPTION_MPC860C0 + 1)
  #define OPTION_INIT                     (OPTION_NO_UNDEFINED + 1)
  #define OPTION_FINI                     (OPTION_INIT + 1)
+ #define OPTION_SECTION_START		(OPTION_FINI + 1)
  
  /* The long options.  This structure is used for both the option
     parsing and the help text.  */
*************** static const struct ld_option ld_options
*** 336,341 ****
--- 337,344 ----
        '\0', N_("SYMBOL"), N_("Do task level linking"), TWO_DASHES },
    { {"traditional-format", no_argument, NULL, OPTION_TRADITIONAL_FORMAT},
        '\0', NULL, N_("Use same format as native linker"), TWO_DASHES },
+   { {"section-start", required_argument, NULL, OPTION_SECTION_START},
+       '\0', N_("SYMBOL=EXPRESSION"), N_("Set address of named section"), TWO_DASHES },
    { {"Tbss", required_argument, NULL, OPTION_TBSS},
        '\0', N_("ADDRESS"), N_("Set address of .bss section"), ONE_DASH },
    { {"Tdata", required_argument, NULL, OPTION_TDATA},
*************** parse_args (argc, argv)
*** 585,590 ****
--- 588,600 ----
  	  parsing_defsym = 1;
  	  yyparse ();
  	  parsing_defsym = 0;
+ 	  lex_string = NULL;
+ 	  break;
+ 	case OPTION_SECTION_START:
+ 	  lex_string = optarg;
+ 	  lex_redirect (optarg);
+ 	  parser_input = input_section_start;
+ 	  yyparse ();
  	  lex_string = NULL;
  	  break;
  	case OPTION_DEMANGLE:
=======================================================================