374 lines
11 KiB
Plaintext
374 lines
11 KiB
Plaintext
# This shell script emits a C file. -*- C -*-
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# It does some substitutions.
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cat >em_${EMULATION_NAME}.c <<EOF
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/* This file is is generated by a shell script. DO NOT EDIT! */
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/* PowerPC/POWER emulation for the linker.
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Copyright (C) 1994 Free Software Foundation, Inc.
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Written by Ian Lance Taylor, Cygnus Support
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This file is part of GLD, the Gnu Linker.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* This file is similar to generic.em. However, we need to build
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linker stubs to handle calls to different modules. A PowerPC call
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is emitted as a two instruction sequence:
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bl .{function}
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cror 31,31,31
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When linking, if the function symbol is defined and in the same
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module, we leave it alone (actually, if it is more than 26 bits
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away we should treat it as though it were in a different module).
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If the function symbol is not defined, we must construct a linker
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stub. We reroute the call to go to the linker stub instead, and we
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change the cror instruction to reload the TOC register value. The
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linker stub looks like this
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l r12,{function}(r2)
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st r2,20(r1)
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l r0,0(r12)
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l r2,4(r12)
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mtctr r0
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bcc
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Since we do not yet support dynamic linking, all function symbols
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are in the same module. However, we still need to create a stub
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for an undefined symbol.
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This is actually probably not correct for the PowerPC ABI.
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However, I do not have that ABI yet. */
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#define TARGET_IS_${EMULATION_NAME}
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#include "bfd.h"
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#include "sysdep.h"
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#include "bfdlink.h"
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/* FIXME! */
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#include "genlink.h"
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#include "ld.h"
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#include "config.h"
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#include "ldmain.h"
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#include "ldemul.h"
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#include "ldfile.h"
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#include "ldmisc.h"
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#include "ldexp.h"
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#include "ldlang.h"
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static void gld${EMULATION_NAME}_before_parse PARAMS ((void));
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static char *gld${EMULATION_NAME}_get_script PARAMS ((int *isfile));
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static void gld${EMULATION_NAME}_create_output_section_statements
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PARAMS ((void));
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static void gld${EMULATION_NAME}_before_allocation PARAMS ((void));
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static boolean gld${EMULATION_NAME}_check_symbol
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PARAMS ((struct bfd_link_hash_entry *, PTR));
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static void
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gld${EMULATION_NAME}_before_parse()
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{
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ldfile_output_architecture = bfd_arch_${ARCH};
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}
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/* Section in which we build stubs. */
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static asection *stub_sec;
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/* Section in which we build TOC entries for stubs. */
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static asection *stub_toc_sec;
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/* This is called before the input files are opened. We create a new
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fake input file to hold the stub section. */
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static void
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gld${EMULATION_NAME}_create_output_section_statements ()
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{
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lang_input_statement_type *stub_file;
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stub_file = lang_add_input_file ("linker stubs",
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lang_input_file_is_fake_enum,
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(char *) NULL);
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stub_file->the_bfd = bfd_create ("linker stubs", output_bfd);
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if (stub_file->the_bfd == (bfd *) NULL
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|| ! bfd_set_arch_mach (stub_file->the_bfd,
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bfd_get_arch (output_bfd),
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bfd_get_mach (output_bfd)))
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{
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einfo ("%X%P: can not create BFD: %E");
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return;
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}
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stub_sec = bfd_make_section_old_way (stub_file->the_bfd, ".text");
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stub_toc_sec = bfd_make_section_old_way (stub_file->the_bfd, ".toc");
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if (stub_sec == (asection *) NULL
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|| stub_toc_sec == (asection *) NULL
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|| ! bfd_set_section_flags (stub_file->the_bfd, stub_sec,
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(SEC_HAS_CONTENTS
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| SEC_ALLOC
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| SEC_LOAD
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| SEC_CODE
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| SEC_RELOC
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| SEC_IN_MEMORY))
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|| ! bfd_set_section_flags (stub_file->the_bfd, stub_toc_sec,
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(SEC_HAS_CONTENTS
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| SEC_ALLOC
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| SEC_LOAD
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| SEC_DATA
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| SEC_RELOC
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| SEC_IN_MEMORY)))
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{
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einfo ("%X%P: can not create stub sections: %E");
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return;
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}
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ldlang_add_file (stub_file);
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}
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/* This is called after the input sections have been attached to the
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output sections but before the output section sizes have been set.
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We can identify the required stubs because they are undefined
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symbols beginning with ".". For each such symbol, we build a stub
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in the .text section. */
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static void
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gld${EMULATION_NAME}_before_allocation ()
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{
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bfd_link_hash_traverse (link_info.hash,
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gld${EMULATION_NAME}_check_symbol,
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(PTR) NULL);
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}
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/* If a particular symbol is undefined and starts with a ".", then we
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need to make a stub for it. */
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/*ARGSUSED*/
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static boolean
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gld${EMULATION_NAME}_check_symbol (h, info)
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struct bfd_link_hash_entry *h;
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PTR info;
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{
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bfd *stub_bfd;
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bfd_byte *p;
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arelent *r;
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struct bfd_link_hash_entry *hnew;
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asymbol *sym;
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if (h->type != bfd_link_hash_undefined
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|| h->root.string[0] != '.')
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return true;
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stub_bfd = stub_sec->owner;
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/* Define this symbol to be the current location in stub_sec. */
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h->type = bfd_link_hash_defined;
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h->u.def.value = bfd_section_size (stub_bfd, stub_sec);
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h->u.def.section = stub_sec;
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/* We want to add this:
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LONG (0x81820000) lwz r12,{TOC index}(r2)
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LONG (0x90410014) stw r2,20(r1)
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LONG (0x800c0000) lwz r0,0(r12)
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LONG (0x804c0004) lwz r2,4(r12)
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LONG (0x7c0903a6) mtctr r0
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LONG (0x4e800420) bctr
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LONG (0) Traceback table
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LONG (0xc8000)
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LONG (0)
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*/
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if (! bfd_set_section_size (stub_bfd, stub_sec,
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h->u.def.value + 9 * 4))
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{
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einfo ("%P%X: can not set section size: %E");
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return false;
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}
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stub_sec->contents = ((bfd_byte *)
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xrealloc ((PTR) stub_sec->contents,
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bfd_section_size (stub_bfd, stub_sec)));
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p = stub_sec->contents + h->u.def.value;
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bfd_put_32 (stub_bfd,
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(bfd_vma) 0x81820000 + bfd_section_size (stub_bfd, stub_toc_sec),
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p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0x90410014, p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0x800c0000, p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0x804c0004, p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0x7c0903a6, p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0x4e800420, p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0, p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0xc8000, p);
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p += 4;
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bfd_put_32 (stub_bfd, (bfd_vma) 0, p);
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/* Add an undefined symbol for the TOC reference. This is the name
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without the leading ".". */
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hnew = bfd_link_hash_lookup (link_info.hash, h->root.string + 1, true,
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false, true);
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if (hnew == (struct bfd_link_hash_entry *) NULL)
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einfo ("%P%F: bfd_link_hash_lookup failed: %E");
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if (hnew->type == bfd_link_hash_new)
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{
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hnew->type = bfd_link_hash_undefined;
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hnew->u.undef.abfd = stub_bfd;
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bfd_link_add_undef (link_info.hash, hnew);
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}
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/* Add a relocation entry for the TOC reference in the first
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instruction. */
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++stub_sec->reloc_count;
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stub_sec->relocation = ((arelent *)
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xrealloc ((PTR) stub_sec->relocation,
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(stub_sec->reloc_count
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* sizeof (arelent))));
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r = &stub_sec->relocation[stub_sec->reloc_count - 1];
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r->sym_ptr_ptr = stub_toc_sec->symbol_ptr_ptr;
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r->address = h->u.def.value;
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if (stub_bfd->xvec->byteorder_big_p)
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r->address += 2;
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r->addend = 0;
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r->howto = bfd_reloc_type_lookup (stub_bfd, BFD_RELOC_PPC_TOC16);
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if (r->howto == (reloc_howto_type *) NULL)
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einfo ("%P%F: no howto for TOC reference: %E");
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/* Add a relocation entry in the TOC section. */
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++stub_toc_sec->reloc_count;
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stub_toc_sec->relocation = ((arelent *)
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xrealloc ((PTR) stub_toc_sec->relocation,
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(stub_toc_sec->reloc_count
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* sizeof (arelent))));
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r = &stub_toc_sec->relocation[stub_toc_sec->reloc_count - 1];
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sym = bfd_make_empty_symbol (stub_bfd);
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sym->name = hnew->root.string;
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sym->value = 0;
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sym->flags = BSF_NO_FLAGS;
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sym->section = &bfd_und_section;
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sym->udata = NULL;
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/* FIXME! */
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((struct generic_link_hash_entry *) hnew)->sym = sym;
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r->sym_ptr_ptr = (asymbol **) xmalloc (sizeof (asymbol *));
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*r->sym_ptr_ptr = sym;
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r->address = bfd_section_size (stub_bfd, stub_toc_sec);
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r->addend = 0;
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r->howto = bfd_reloc_type_lookup (stub_bfd, BFD_RELOC_32);
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if (r->howto == (reloc_howto_type *) NULL)
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einfo ("%P%F: no howto for TOC entry: %E");
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/* Add more space to the .toc section. */
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if (! bfd_set_section_size (stub_bfd, stub_toc_sec,
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bfd_section_size (stub_bfd, stub_toc_sec) + 4))
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{
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einfo ("%P%X: can not set section size: %E");
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return false;
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}
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stub_toc_sec->contents = ((bfd_byte *)
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xrealloc ((PTR) stub_toc_sec->contents,
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bfd_section_size (stub_bfd,
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stub_toc_sec)));
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bfd_put_32 (stub_bfd, (bfd_vma) 0,
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(stub_toc_sec->contents
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+ bfd_section_size (stub_bfd, stub_toc_sec)
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- 4));
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return true;
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}
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static char *
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gld${EMULATION_NAME}_get_script(isfile)
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int *isfile;
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EOF
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if test -n "$COMPILE_IN"
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then
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# Scripts compiled in.
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# sed commands to quote an ld script as a C string.
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sc='s/["\\]/\\&/g
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s/$/\\n\\/
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1s/^/"/
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$s/$/n"/
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'
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cat >>em_${EMULATION_NAME}.c <<EOF
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{
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*isfile = 0;
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if (link_info.relocateable == true && config.build_constructors == true)
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return `sed "$sc" ldscripts/${EMULATION_NAME}.xu`;
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else if (link_info.relocateable == true)
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return `sed "$sc" ldscripts/${EMULATION_NAME}.xr`;
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else if (!config.text_read_only)
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return `sed "$sc" ldscripts/${EMULATION_NAME}.xbn`;
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else if (!config.magic_demand_paged)
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return `sed "$sc" ldscripts/${EMULATION_NAME}.xn`;
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else
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return `sed "$sc" ldscripts/${EMULATION_NAME}.x`;
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}
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EOF
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else
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# Scripts read from the filesystem.
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cat >>em_${EMULATION_NAME}.c <<EOF
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{
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*isfile = 1;
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if (link_info.relocateable == true && config.build_constructors == true)
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return "ldscripts/${EMULATION_NAME}.xu";
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else if (link_info.relocateable == true)
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return "ldscripts/${EMULATION_NAME}.xr";
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else if (!config.text_read_only)
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return "ldscripts/${EMULATION_NAME}.xbn";
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else if (!config.magic_demand_paged)
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return "ldscripts/${EMULATION_NAME}.xn";
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else
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return "ldscripts/${EMULATION_NAME}.x";
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}
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EOF
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fi
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cat >>em_${EMULATION_NAME}.c <<EOF
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struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
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{
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gld${EMULATION_NAME}_before_parse,
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syslib_default,
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hll_default,
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after_parse_default,
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after_allocation_default,
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set_output_arch_default,
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ldemul_default_target,
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gld${EMULATION_NAME}_before_allocation,
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gld${EMULATION_NAME}_get_script,
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"${EMULATION_NAME}",
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"${OUTPUT_FORMAT}",
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0,
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gld${EMULATION_NAME}_create_output_section_statements
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};
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EOF
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