instead of our custom .go format, use elf

* libguile/objcodes.c: Change to expect objcode on disk to be embedded
  in ELF instead of having the funky cookie.

  (to_native_order): Use already existing SCM_BYTE_ORDER style byte
  order instead of chars.
  (bytecode_to_objcode): No need for word_size arg.
  (scm_bytecode_to_objcode, scm_objcode_to_bytecode): Take optional
  endianness arg instead of sometimes using target-endianness.
  (scm_load_objcode, scm_write_objcode, scm_bytecode_to_native_objcode):
  Remove.

* libguile/objcodes.h: Adapt.

* libguile/vm.c (scm_load_compiled_with_vm): Use
  scm_load_thunk_from_file.
  (make_boot_program): Adapt to use scm_bytecode_to_objcode with
  endianness arg.

* module/Makefile.am (OBJCODE_LANG_SOURCES): Add (language objcode
  elf).
* module/language/objcode/elf.scm: New module, embeds objcode in ELF.

* module/language/bytecode/spec.scm (compile-objcode):
  (decompile-objcode): Use (target-endianness).

* module/language/objcode/spec.scm: use (language objcode elf) for
  write-objcode.

* module/scripts/disassemble.scm (disassemble):
* module/system/repl/command.scm (disassemble-file): Use
  load-thunk-from-file.

* module/system/vm/objcode.scm: Remove load-objcode and write-objcode.

* test-suite/tests/asm-to-bytecode.test (test-target): Adapt to the new
  ELF world.

module/language/objcode/elf.scm

@@ -0,0 +1,94 @@
+;;; Embedding bytecode in ELF
+
+;; Copyright (C) 2012 Free Software Foundation, Inc.
+
+;;;; This library is free software; you can redistribute it and/or
+;;;; modify it under the terms of the GNU Lesser General Public
+;;;; License as published by the Free Software Foundation; either
+;;;; version 3 of the License, or (at your option) any later version.
+;;;; 
+;;;; This library 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
+;;;; Lesser General Public License for more details.
+;;;; 
+;;;; You should have received a copy of the GNU Lesser General Public
+;;;; License along with this library; if not, write to the Free Software
+;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+;;; Code:
+
+;; The eval-when is because (language objcode elf) will not be loaded
+;; yet when we go to compile it, but later passes of the
+;; compiler need it.  So we have to be sure that the module is present
+;; at compile time, with all of its definitions.  The easiest way to do
+;; that is just to go ahead and resolve it now.
+;;
+(define-module (language objcode elf)
+  #:use-module (system vm objcode)
+  #:use-module (system base target)
+  #:use-module (rnrs bytevectors)
+  #:use-module (ice-9 binary-ports)
+  #:use-module (system vm elf)
+  #:export (write-objcode))
+
+(define (bytecode->elf bv)
+  (let ((string-table (make-elf-string-table)))
+    (define (intern-string! string)
+      (call-with-values
+          (lambda () (elf-string-table-intern string-table string))
+        (lambda (table idx)
+          (set! string-table table)
+          idx)))
+    (define (make-object name bv relocs . kwargs)
+      (let ((name-idx (intern-string! (symbol->string name))))
+        (make-elf-object (apply make-elf-section
+                                #:name name-idx
+                                #:size (bytevector-length bv)
+                                kwargs)
+                         bv relocs
+                         (list (make-elf-symbol name 0)))))
+    (define (make-dynamic-section word-size endianness)
+      (define (make-dynamic-section/32)
+        (let ((bv (make-bytevector 24 0)))
+          (bytevector-u32-set! bv 0 DT_GUILE_RTL_VERSION endianness)
+          (bytevector-u32-set! bv 4 #x02000000 endianness)
+          (bytevector-u32-set! bv 8 DT_GUILE_ENTRY endianness)
+          (bytevector-u32-set! bv 12 0 endianness)
+          (bytevector-u32-set! bv 16 DT_NULL endianness)
+          (bytevector-u32-set! bv 20 0 endianness)
+          (values bv (make-elf-reloc 'abs32/1 12 0 '.rtl-text))))
+      (define (make-dynamic-section/64)
+        (let ((bv (make-bytevector 48 0)))
+          (bytevector-u64-set! bv 0 DT_GUILE_RTL_VERSION endianness)
+          (bytevector-u64-set! bv 8 #x02000000 endianness)
+          (bytevector-u64-set! bv 16 DT_GUILE_ENTRY endianness)
+          (bytevector-u64-set! bv 24 0 endianness)
+          (bytevector-u64-set! bv 32 DT_NULL endianness)
+          (bytevector-u64-set! bv 40 0 endianness)
+          (values bv (make-elf-reloc 'abs64/1 24 0 '.rtl-text))))
+      (call-with-values (lambda ()
+                          (case word-size
+                            ((4) (make-dynamic-section/32))
+                            ((8) (make-dynamic-section/64))
+                            (else (error "unexpected word size" word-size))))
+        (lambda (bv reloc)
+          (make-object '.dynamic bv (list reloc)
+                       #:type SHT_DYNAMIC #:flags SHF_ALLOC))))
+    (define (link-string-table)
+      (intern-string! ".shstrtab")
+      (make-object '.shstrtab (link-elf-string-table string-table) '()
+                   #:type SHT_STRTAB #:flags 0))
+    (let* ((word-size (target-word-size))
+           (endianness (target-endianness))
+           (text (make-object '.rtl-text bv '()))
+           (dt (make-dynamic-section word-size endianness))
+           ;; This needs to be linked last, because linking other
+           ;; sections adds entries to the string table.
+           (shstrtab (link-string-table)))
+      (link-elf (list text dt shstrtab)
+                #:endianness endianness #:word-size word-size))))
+
+(define (write-objcode objcode port)
+  (let ((bv (objcode->bytecode objcode (target-endianness))))
+    (put-bytevector port (bytecode->elf bv))))

module/language/objcode/spec.scm

@@ -22,6 +22,7 @@
   #:use-module (system base language)
   #:use-module (system vm objcode)
   #:use-module (system vm program)
+  #:use-module (language objcode elf)
   #:export (objcode))
 
 (define (objcode->value x e opts)