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Add ALIGNOF


This patch adds an ALIGNOF linker script operator. It returns the alignment of an output section.

This is needed for upcoming vxworks __thread support, which is implemented in a target independent fashion that avoids any existing TLS support such a target might have.

ok?

nathan
--
Nathan Sidwell    ::   http://www.codesourcery.com   ::         CodeSourcery
nathan@codesourcery.com    ::     http://www.planetfall.pwp.blueyonder.co.uk

2007-06-11  Nathan Sidwell  <nathan@codesourcery.com>

	ld/
	* ldlex.l, ldgram.y: Add ALIGNOF.
	* ldexp.c (exp_print_token, foldname): Likewise.
	* ld.texinfo: Likewise.

	ld/testsuite/
	* ld-scripts/alignof.s: New.
	* ld-scripts/alignof.t: New
	* ld-scripts/alignof.exp: New.

Index: ld/ldlex.l
===================================================================
--- ld/ldlex.l	(revision 173558)
+++ ld/ldlex.l	(working copy)
@@ -254,6 +254,7 @@ V_IDENTIFIER [*?.$_a-zA-Z\[\]\-\!\^\\]([
 <EXPRESSION,BOTH,SCRIPT>"DATA_SEGMENT_END"	{ RTOKEN(DATA_SEGMENT_END);}
 <EXPRESSION,BOTH,SCRIPT>"ADDR"		{ RTOKEN(ADDR);}
 <EXPRESSION,BOTH,SCRIPT>"LOADADDR"	{ RTOKEN(LOADADDR);}
+<EXPRESSION,BOTH>"ALIGNOF"		{ RTOKEN(ALIGNOF); }
 <EXPRESSION,BOTH>"MAX"			{ RTOKEN(MAX_K); }
 <EXPRESSION,BOTH>"MIN"			{ RTOKEN(MIN_K); }
 <EXPRESSION,BOTH>"ASSERT"		{ RTOKEN(ASSERT_K); }
Index: ld/ldgram.y
===================================================================
--- ld/ldgram.y	(revision 173558)
+++ ld/ldgram.y	(working copy)
@@ -137,7 +137,7 @@ static int error_index;
 %token NOLOAD DSECT COPY INFO OVERLAY
 %token DEFINED TARGET_K SEARCH_DIR MAP ENTRY
 %token <integer> NEXT
-%token SIZEOF ADDR LOADADDR MAX_K MIN_K
+%token SIZEOF ALIGNOF ADDR LOADADDR MAX_K MIN_K
 %token STARTUP HLL SYSLIB FLOAT NOFLOAT NOCROSSREFS
 %token ORIGIN FILL
 %token LENGTH CREATE_OBJECT_SYMBOLS INPUT GROUP OUTPUT CONSTRUCTORS
@@ -837,6 +837,8 @@ exp	:
         |	SIZEOF_HEADERS
 			{ $$ = exp_nameop (SIZEOF_HEADERS,0); }
 
+	|	ALIGNOF '(' NAME ')'
+			{ $$ = exp_nameop (ALIGNOF,$3); }
 	|	SIZEOF '(' NAME ')'
 			{ $$ = exp_nameop (SIZEOF,$3); }
 	|	ADDR '(' NAME ')'
Index: ld/ldexp.c
===================================================================
--- ld/ldexp.c	(revision 173558)
+++ ld/ldexp.c	(working copy)
@@ -97,6 +97,7 @@ exp_print_token (token_code_type code, i
     { MAP, "MAP" },
     { ENTRY, "ENTRY" },
     { NEXT, "NEXT" },
+    { ALIGNOF, "ALIGNOF" },
     { SIZEOF, "SIZEOF" },
     { ADDR, "ADDR" },
     { LOADADDR, "LOADADDR" },
@@ -606,6 +607,7 @@ fold_name (etree_type *tree)
       break;
 
     case SIZEOF:
+    case ALIGNOF:
       if (expld.phase != lang_first_phase_enum)
 	{
 	  int opb = bfd_octets_per_byte (output_bfd);
@@ -620,7 +622,15 @@ fold_name (etree_type *tree)
 	      new_abs (0);
 	    }
 	  else if (os->processed_vma)
-	    new_abs (os->bfd_section->size / opb);
+	    {
+	      bfd_vma val;
+	      
+	      val = tree->type.node_code == SIZEOF
+		? os->bfd_section->size
+		: (bfd_vma)1 << os->bfd_section->alignment_power;
+	      
+	      new_abs (val / opb);
+	    }
 	}
       break;
 
Index: ld/ld.texinfo
===================================================================
--- ld/ld.texinfo	(revision 173558)
+++ ld/ld.texinfo	(working copy)
@@ -5004,6 +5004,25 @@ of @code{ALIGN} is used to defines the v
 
 The builtin function @code{NEXT} is closely related to @code{ALIGN}.
 
+@item ALIGNOF(@var{section})
+@kindex ALIGNOF(@var{section})
+@cindex section alignment
+Return the alignment in bytes of the named @var{section}, if that section has
+been allocated.  If the section has not been allocated when this is
+evaluated, the linker will report an error. In the following example,
+the alignment of the @code{.output} section is stored as the first
+value in that section.
+@smallexample
+@group
+SECTIONS@{ @dots{}
+  .output @{
+    LONG (ALIGNOF (.output))
+    @dots{}
+    @}
+@dots{} @}
+@end group
+@end smallexample
+
 @item BLOCK(@var{exp})
 @kindex BLOCK(@var{exp})
 This is a synonym for @code{ALIGN}, for compatibility with older linker
Index: ld/testsuite/ld-scripts/alignof.s
===================================================================
--- ld/testsuite/ld-scripts/alignof.s	(revision 0)
+++ ld/testsuite/ld-scripts/alignof.s	(revision 0)
@@ -0,0 +1,9 @@
+
+	.text
+	.p2align 6
+	.long 0
+
+	.data
+	.p2align 4
+	.long 0
+	
Index: ld/testsuite/ld-scripts/alignof.t
===================================================================
--- ld/testsuite/ld-scripts/alignof.t	(revision 0)
+++ ld/testsuite/ld-scripts/alignof.t	(revision 0)
@@ -0,0 +1,15 @@
+SECTIONS {
+	.text :
+	  {
+	    tmpdir/alignof.o (.text)
+	  }
+	.data : 
+	  { 
+	    tmpdir/alignof.o (.data)
+	    LONG (ALIGNOF(.text))
+	    LONG (ALIGNOF(.data))
+	  }
+}	
+
+alignof_text = ALIGNOF(.text);
+alignof_data = ALIGNOF(.data);
Index: ld/testsuite/ld-scripts/alignof.exp
===================================================================
--- ld/testsuite/ld-scripts/alignof.exp	(revision 0)
+++ ld/testsuite/ld-scripts/alignof.exp	(revision 0)
@@ -0,0 +1,57 @@
+# Test ALIGNOF in a linker script.
+# By Nathan Sidwell <nathan@codesourcery.com>
+#
+# This file is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+
+set testname "ALIGNOF"
+
+if ![ld_assemble $as $srcdir/$subdir/alignof.s tmpdir/alignof.o] {
+    unresolved $testname
+    return
+}
+
+if ![ld_simple_link $ld tmpdir/alignof "-T $srcdir/$subdir/alignof.t tmpdir/alignof.o"] {
+    fail $testname
+    return
+}
+
+if ![ld_nm $nm "" tmpdir/alignof] {
+    unresolved $testname
+    return
+}
+
+if {![info exists nm_output(alignof_text)] \
+     || ![info exists nm_output(alignof_data)]} {
+    send_log "bad output from nm\n"
+    verbose "bad output from nm"
+    fail $testname
+    return
+}
+
+if {$nm_output(alignof_text) != 64} {
+    send_log "alignof_text != 64\n"
+    verbose "alignof_text != 64"
+    fail $testname
+    return
+}
+
+if {$nm_output(alignof_data) != 16} {
+    send_log "alignof_data != 16\n"
+    verbose "alignof_data != 16"
+    fail $testname
+    return
+}
+
+pass $testname

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