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Commit: MSP430: Add support for low & high memory regions


Hi Guys,

  This patch adds support to the MSP430 assembler and linker for the
  automatic placement of code and data into either low (< 64K) or high
  memory.  It works in conjunction with a compiler patch, which will be
  submitted soon.

  Code that should be placed into low memory until that runs out and
  then into high memory is held in a section called .either.text.  When
  the linker detects input sections of this name it attempts to place
  them into a section called .lower.text until this is full.  Then it
  starts to place them into a section called .upper.text.  This requires
  the cooperation of the linker scripts to make sure that the relevant
  sections are available.

  A similar technique is used for data, although this involves sections
  called .upper.data, .upper.rodata and .upper.bss.
  
  The patch also updates the assembler so that the init symbols for the
  high data regions are created.

Cheers
  Nick

gas/ChangeLog
2015-05-05  Nick Clifton  <nickc@redhat.com>

	* config/tc-msp430.c (MAX_OP_LEN): Increase to 4096.
	(msp430_make_init_symbols): New function.
	(msp430_section): Call it.
	(msp430_frob_section): Likewise.

ld/ChangeLog
2015-05-05  Nick Clifton  <nickc@redhat.com>

	* emulparams/msp430elf.sh (TEMPLATE_NAME): Change to msp430.
	* scripttempl/msp430.sc (.text): Add .lower.text and .either.text.
	(.data): Add .lower.data and .either.data.
	(.bss): Add .lower.bss and .either.bss.
	(.rodata): Add .lower.rodata and .either.rodata.
	* emultempl/msp430.em: New file.  Implements a new orphan
	placement algorithm that divides sections between lower and upper
	memory regions.
	* Makefile.am (emsp430elf.c): Depend upon msp430.em.
	*emsp430X.c): Likewise.
	* Makefine.in: Regenerate.

diff --git a/gas/config/tc-msp430.c b/gas/config/tc-msp430.c
index 2891c13..5307746 100644
--- a/gas/config/tc-msp430.c
+++ b/gas/config/tc-msp430.c
@@ -255,7 +255,7 @@ relax_typeS md_relax_table[] =
 };
 
 
-#define MAX_OP_LEN	256
+#define MAX_OP_LEN	4096
 
 typedef enum msp_isa
 {
@@ -840,14 +840,11 @@ md_parse_option (int c, char * arg)
 
    The code which initializes these sections should have a global
    label for these symbols, and should be marked with KEEP() in the
-   linker script.
- */
+   linker script.  */
+
 static void
-msp430_section (int arg)
+msp430_make_init_symbols (const char * name)
 {
-  char * saved_ilp = input_line_pointer;
-  char * name = obj_elf_section_name ();
-
   if (strncmp (name, ".bss", 4) == 0
       || strncmp (name, ".gnu.linkonce.b.", 16) == 0)
     (void) symbol_find_or_make ("__crt0_init_bss");
@@ -856,6 +853,27 @@ msp430_section (int arg)
       || strncmp (name, ".gnu.linkonce.d.", 16) == 0)
     (void) symbol_find_or_make ("__crt0_movedata");
 
+  /* Note - data assigned to the .either.data section may end up being
+     placed in the .upper.data section if the .lower.data section is
+     full.  Hence the need to define the crt0 symbol.  */
+  if (strncmp (name, ".either.data", 12) == 0
+      || strncmp (name, ".upper.data", 11) == 0)
+    (void) symbol_find_or_make ("__crt0_move_highdata");
+
+  /* See note about .either.data above.  */
+  if (strncmp (name, ".upper.bss", 10) == 0
+      || strncmp (name, ".either.bss", 11) == 0)
+    (void) symbol_find_or_make ("__crt0_init_highbss");
+}
+
+static void
+msp430_section (int arg)
+{
+  char * saved_ilp = input_line_pointer;
+  char * name = obj_elf_section_name ();
+
+  msp430_make_init_symbols (name);
+    
   input_line_pointer = saved_ilp;
   obj_elf_section (arg);
 }
@@ -868,13 +886,7 @@ msp430_frob_section (asection *sec)
   if (sec->size == 0)
     return;
 
-  if (strncmp (name, ".bss", 4) == 0
-      || strncmp (name, ".gnu.linkonce.b.", 16) == 0)
-    (void) symbol_find_or_make ("__crt0_init_bss");
-
-  if (strncmp (name, ".data", 5) == 0
-      || strncmp (name, ".gnu.linkonce.d.", 16) == 0)
-    (void) symbol_find_or_make ("__crt0_movedata");
+  msp430_make_init_symbols (name);
 }
 
 static void
diff --git a/ld/Makefile.am b/ld/Makefile.am
index 15f8994..ee22e75 100644
--- a/ld/Makefile.am
+++ b/ld/Makefile.am
@@ -1529,9 +1529,11 @@ emn10300.c: $(srcdir)/emulparams/mn10300.sh \
   $(ELF_DEPS) $(srcdir)/scripttempl/elf.sc ${GEN_DEPENDS}
 
 emsp430elf.c: $(srcdir)/emulparams/msp430elf.sh \
+  $(ELF_DEPS) $(srcdir)/emultempl/msp430.em \
   $(ELF_GEN_DEPS) $(srcdir)/scripttempl/elf32msp430.sc ${GEN_DEPENDS}
 
 emsp430X.c: $(srcdir)/emulparams/msp430elf.sh $(srcdir)/emulparams/msp430X.sh \
+  $(ELF_DEPS) $(srcdir)/emultempl/msp430.em \
   $(ELF_GEN_DEPS) $(srcdir)/scripttempl/elf32msp430.sc ${GEN_DEPENDS}
 
 ends32elf.c: $(srcdir)/emulparams/nds32elf.sh \
diff --git a/ld/emulparams/msp430elf.sh b/ld/emulparams/msp430elf.sh
index b459698..a76e9ee 100644
--- a/ld/emulparams/msp430elf.sh
+++ b/ld/emulparams/msp430elf.sh
@@ -3,7 +3,7 @@
 # This called by genscripts_extra.sh
 
 SCRIPT_NAME=elf32msp430
-TEMPLATE_NAME=generic
+TEMPLATE_NAME=msp430
 EXTRA_EM_FILE=genelf
 OUTPUT_FORMAT="elf32-msp430"
 MACHINE=
diff --git a/ld/scripttempl/elf32msp430.sc b/ld/scripttempl/elf32msp430.sc
index 15d5630..65105e5 100644
--- a/ld/scripttempl/elf32msp430.sc
+++ b/ld/scripttempl/elf32msp430.sc
@@ -154,12 +154,17 @@ SECTIONS
     ${CONSTRUCTING+ __dtors_end = . ; }
 
     ${RELOCATING+. = ALIGN(2);}
+    *(.lower.text.* .lower.text)
+
+    ${RELOCATING+. = ALIGN(2);}
     *(.text)
     ${RELOCATING+. = ALIGN(2);}
     *(.text.*)
     ${RELOCATING+. = ALIGN(2);}
     *(.text:*)
 
+    *(.either.text.* .either.text)
+
     ${RELOCATING+. = ALIGN(2);}
     *(SORT_NONE(.fini9))
     *(SORT_NONE(.fini8))
@@ -178,11 +183,15 @@ SECTIONS
 
   .rodata :
   {
+    ${RELOCATING+. = ALIGN(2);}
+    *(.lower.rodata.* .lower.rodata)
+
     . = ALIGN(2);
     *(.plt)
     *(.rodata .rodata.* .gnu.linkonce.r.* .const .const:*)
     *(.rodata1)
 
+    *(.either.rodata.*) *(.either.rodata)
     *(.eh_frame_hdr)
     KEEP (*(.eh_frame))
 
@@ -242,23 +251,32 @@ SECTIONS
     *(.data.rel.ro.local) *(.data.rel.ro*)
     *(.dynamic)
 
+    ${RELOCATING+. = ALIGN(2);}
+    *(.lower.data.* .lower.data)
+
     *(.data)
     *(.data.*)
     *(.gnu.linkonce.d*)
     KEEP (*(.gnu.linkonce.d.*personality*))
     *(.data1)
+
+    *(.either.data.* .either.data)
+
     *(.got.plt) *(.got)
     ${RELOCATING+. = ALIGN(2);}
     *(.sdata .sdata.* .gnu.linkonce.s.*)
     ${RELOCATING+. = ALIGN(2);}
     ${RELOCATING+ _edata = . ; }
   } ${RELOCATING+ > data ${RELOCATING+AT> text}}
-  
+
   .bss ${RELOCATING+ SIZEOF(.data) + ADDR(.data)} :
   {
     ${RELOCATING+. = ALIGN(2);}
     ${RELOCATING+ PROVIDE (__bss_start = .) ; }
+    *(.lower.bss.* .lower.bss)
+    ${RELOCATING+. = ALIGN(2);}
     *(.bss)
+    *(.either.bss.* .either.bss)
     *(COMMON)
     ${RELOCATING+ PROVIDE (__bss_end = .) ; }
     ${RELOCATING+ _end = . ;  }

--- /dev/null	2015-05-05 08:07:19.045105421 +0100
+++ ld/emultempl/msp430.em	2015-05-05 11:26:10.736898011 +0100
@@ -0,0 +1,298 @@
+# This shell script emits a C file. -*- C -*-
+# It does some substitutions.
+fragment <<EOF
+/* This file is is generated by a shell script.  DO NOT EDIT! */
+
+/* Emulate the original gld for the given ${EMULATION_NAME}
+   Copyright (C) 2014-2015 Free Software Foundation, Inc.
+   Written by Steve Chamberlain steve@cygnus.com
+   Extended for the MSP430 by Nick Clifton  nickc@redhat.com
+   
+   This file is part of the GNU Binutils.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+   MA 02110-1301, USA.  */
+
+#define TARGET_IS_${EMULATION_NAME}
+
+#include "sysdep.h"
+#include "bfd.h"
+#include "bfdlink.h"
+
+#include "ld.h"
+#include "ldmain.h"
+#include "ldmisc.h"
+#include "ldexp.h"
+#include "ldlang.h"
+#include "ldfile.h"
+#include "ldemul.h"
+#include "libiberty.h"
+
+EOF
+
+# Import any needed special functions and/or overrides.
+#
+if test -n "$EXTRA_EM_FILE" ; then
+  source_em ${srcdir}/emultempl/${EXTRA_EM_FILE}.em
+fi
+
+if test x"$LDEMUL_BEFORE_PARSE" != xgld"$EMULATION_NAME"_before_parse; then
+fragment <<EOF
+
+static void
+gld${EMULATION_NAME}_before_parse (void)
+{
+#ifndef TARGET_			/* I.e., if not generic.  */
+  ldfile_set_output_arch ("`echo ${ARCH}`", bfd_arch_unknown);
+#endif /* not TARGET_ */
+
+  /* The MSP430 port *needs* linker relaxtion in order to cope with large
+     functions where conditional branches do not fit into a +/- 1024 byte range.  */
+  if (! link_info.relocatable)
+    TARGET_ENABLE_RELAXATION;
+}
+
+EOF
+fi
+
+if test x"$LDEMUL_GET_SCRIPT" != xgld"$EMULATION_NAME"_get_script; then
+fragment <<EOF
+
+static char *
+gld${EMULATION_NAME}_get_script (int *isfile)
+EOF
+
+if test x"$COMPILE_IN" = xyes
+then
+# Scripts compiled in.
+
+# sed commands to quote an ld script as a C string.
+sc="-f stringify.sed"
+
+fragment <<EOF
+{
+  *isfile = 0;
+
+  if (link_info.relocatable && config.build_constructors)
+    return
+EOF
+sed $sc ldscripts/${EMULATION_NAME}.xu                 >> e${EMULATION_NAME}.c
+echo '  ; else if (link_info.relocatable) return'      >> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xr                 >> e${EMULATION_NAME}.c
+echo '  ; else if (!config.text_read_only) return'     >> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xbn                >> e${EMULATION_NAME}.c
+echo '  ; else if (!config.magic_demand_paged) return' >> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xn                 >> e${EMULATION_NAME}.c
+echo '  ; else return'                                 >> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.x                  >> e${EMULATION_NAME}.c
+echo '; }'                                             >> e${EMULATION_NAME}.c
+
+else
+# Scripts read from the filesystem.
+
+fragment <<EOF
+{
+  *isfile = 1;
+
+  if (link_info.relocatable && config.build_constructors)
+    return "ldscripts/${EMULATION_NAME}.xu";
+  else if (link_info.relocatable)
+    return "ldscripts/${EMULATION_NAME}.xr";
+  else if (!config.text_read_only)
+    return "ldscripts/${EMULATION_NAME}.xbn";
+  else if (!config.magic_demand_paged)
+    return "ldscripts/${EMULATION_NAME}.xn";
+  else
+    return "ldscripts/${EMULATION_NAME}.x";
+}
+EOF
+fi
+fi
+
+if test x"$LDEMUL_PLACE_ORPHAN" != xgld"$EMULATION_NAME"_place_orphan; then
+fragment <<EOF
+
+/* Helper function for place_orphan that computes the size
+   of sections already mapped to the given statement.  */
+
+static bfd_size_type
+scan_children (lang_statement_union_type * l)
+{
+  bfd_size_type amount = 0;
+
+  while (l != NULL)
+    {
+      switch (l->header.type)
+	{
+	case lang_input_section_enum:
+	  if (l->input_section.section->flags & SEC_ALLOC)
+	    amount += l->input_section.section->size;
+	  break;
+
+	case lang_constructors_statement_enum:
+	case lang_assignment_statement_enum:
+	  break;
+
+	case lang_wild_statement_enum:
+	  amount += scan_children (l->wild_statement.children.head);	  
+	  break;
+
+	default:
+	  fprintf (stderr, "msp430 orphan placer: unhandled lang type %d\n", l->header.type);
+	  break;
+	}
+
+      l = l->header.next;
+    }
+
+  return amount;
+}
+  
+/* Place an orphan section.  We use this to put .either sections
+   into either their lower or their upper equivalents.  */
+
+static lang_output_section_statement_type *
+gld${EMULATION_NAME}_place_orphan (asection * s,
+				   const char * secname,
+				   int constraint)
+{
+  char * lower_name;
+  char * upper_name;
+  char * name;
+  lang_output_section_statement_type * lower;
+  lang_output_section_statement_type * upper;
+  lang_output_section_statement_type * os;
+
+  if ((s->flags & SEC_ALLOC) == 0)
+    return NULL;
+
+  if (link_info.relocatable)
+    return NULL;
+
+  /* If constraints are involved let the linker handle the placement normally.  */
+  if (constraint != 0)
+    return NULL;
+
+  /* We only need special handling for .either sections.  */
+  if (strncmp (secname, ".either.", 8) != 0)
+    return NULL;
+
+  /* Skip the .either prefix.  */
+  secname += 7;
+
+  /* Compute the names of the corresponding upper and lower
+     sections.  If the input section name contains another period,
+     only use the part of the name before the second dot.  */
+  if (strchr (secname + 1, '.') != NULL)
+    {
+      name = ACONCAT ((secname, NULL));
+
+      * strchr (name + 1, '.') = 0;
+    }
+  else
+    name = (char *) secname;
+  
+  lower_name = ACONCAT ((".lower", name, NULL));
+  upper_name = ACONCAT ((".upper", name, NULL));
+
+  /* Find the corresponding lower and upper sections.  */
+  lower = lang_output_section_find (lower_name);
+  upper = lang_output_section_find (upper_name);
+  /* If the upper section does not exist, try again without the suffix.  */
+  if (upper == NULL)
+    upper = lang_output_section_find (name);
+
+  if (lower == NULL)
+    {
+      os = upper;
+      if (upper == NULL)
+        {
+          einfo ("%P: error: no section named %s or %s in linker script\n", lower_name, upper_name);
+	  return NULL;
+	}
+    }
+  else if (upper == NULL)
+    os = lower;
+  else if (lower->region == NULL)
+    os = lower;
+  /* If the section is too big for the region containing
+     the lower section then do not even try to use it.  */
+  else if (lower->region->length < s->size)
+    os = upper;
+  else
+    {
+      bfd_size_type amount = 0;
+      struct lang_output_section_statement_struct * p;
+
+      amount += scan_children (lower->children.head);
+
+      /* Also check forwards for other statements assigned to the same region.  */
+      for (p = lower->next; p != NULL; p = p->next)
+	if (p->region == lower->region)
+	  amount += scan_children (p->children.head);
+
+      /* Scan backwards as well.  */      
+      for (p = lower->prev; p != NULL; p = p->prev)
+	if (p->region == lower->region)
+	  amount += scan_children (p->children.head);
+
+      if (amount + s->size >= lower->region->length)
+	os = upper;
+      else
+	os = lower;
+    }
+
+  lang_add_section (& os->children, s, NULL, os);
+  return os;
+}
+EOF
+fi
+
+fragment <<EOF
+
+struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
+{
+  ${LDEMUL_BEFORE_PARSE-gld${EMULATION_NAME}_before_parse},
+  ${LDEMUL_SYSLIB-syslib_default},
+  ${LDEMUL_HLL-hll_default},
+  ${LDEMUL_AFTER_PARSE-after_parse_default},
+  ${LDEMUL_AFTER_OPEN-after_open_default},
+  ${LDEMUL_AFTER_ALLOCATION-after_allocation_default},
+  ${LDEMUL_SET_OUTPUT_ARCH-set_output_arch_default},
+  ${LDEMUL_CHOOSE_TARGET-ldemul_default_target},
+  ${LDEMUL_BEFORE_ALLOCATION-before_allocation_default},
+  ${LDEMUL_GET_SCRIPT-gld${EMULATION_NAME}_get_script},
+  "${EMULATION_NAME}",
+  "${OUTPUT_FORMAT}",
+  ${LDEMUL_FINISH-finish_default},
+  ${LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS-NULL},
+  ${LDEMUL_OPEN_DYNAMIC_ARCHIVE-NULL},
+  ${LDEMUL_PLACE_ORPHAN-gld${EMULATION_NAME}_place_orphan},
+  ${LDEMUL_SET_SYMBOLS-NULL},
+  ${LDEMUL_PARSE_ARGS-NULL},
+  ${LDEMUL_ADD_OPTIONS-NULL},
+  ${LDEMUL_HANDLE_OPTION-NULL},
+  ${LDEMUL_UNRECOGNIZED_FILE-NULL},
+  ${LDEMUL_LIST_OPTIONS-NULL},
+  ${LDEMUL_RECOGNIZED_FILE-NULL},
+  ${LDEMUL_FIND_POTENTIAL_LIBRARIES-NULL},
+  ${LDEMUL_NEW_VERS_PATTERN-NULL},
+  ${LDEMUL_EXTRA_MAP_FILE_TEXT-NULL}
+};
+EOF
+# 
+# Local Variables:
+# mode: c
+# End:


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