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-rw-r--r--module/language/objcode/elf.scm94
-rw-r--r--module/language/objcode/spec.scm1
2 files changed, 95 insertions, 0 deletions
diff --git a/module/language/objcode/elf.scm b/module/language/objcode/elf.scm
new file mode 100644
index 000000000..9654c0861
--- /dev/null
+++ b/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))))
diff --git a/module/language/objcode/spec.scm b/module/language/objcode/spec.scm
index 7cc85b7f6..022419e9d 100644
--- a/module/language/objcode/spec.scm
+++ b/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)