Commit | Line | Data |
---|---|---|
7b107cce AW |
1 | ;;; Guile VM code converters |
2 | ||
9b7ca73c | 3 | ;; Copyright (C) 2001, 2009, 2010 Free Software Foundation, Inc. |
7b107cce | 4 | |
53befeb7 NJ |
5 | ;;;; This library is free software; you can redistribute it and/or |
6 | ;;;; modify it under the terms of the GNU Lesser General Public | |
7 | ;;;; License as published by the Free Software Foundation; either | |
8 | ;;;; version 3 of the License, or (at your option) any later version. | |
9 | ;;;; | |
10 | ;;;; This library is distributed in the hope that it will be useful, | |
11 | ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | ;;;; Lesser General Public License for more details. | |
14 | ;;;; | |
15 | ;;;; You should have received a copy of the GNU Lesser General Public | |
16 | ;;;; License along with this library; if not, write to the Free Software | |
17 | ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
7b107cce AW |
18 | |
19 | ;;; Code: | |
20 | ||
21 | (define-module (language assembly decompile-bytecode) | |
22 | #:use-module (system vm instruction) | |
23 | #:use-module (system base pmatch) | |
24 | #:use-module (srfi srfi-4) | |
15939985 | 25 | #:use-module (rnrs bytevector) |
7b107cce | 26 | #:use-module (language assembly) |
6cf48307 | 27 | #:use-module ((system vm objcode) #:select (byte-order)) |
7b107cce AW |
28 | #:export (decompile-bytecode)) |
29 | ||
30 | (define (decompile-bytecode x env opts) | |
31 | (let ((i 0) (size (u8vector-length x))) | |
32 | (define (pop) | |
33 | (let ((b (cond ((< i size) (u8vector-ref x i)) | |
34 | ((= i size) #f) | |
35 | (else (error "tried to decode too many bytes"))))) | |
36 | (if b (set! i (1+ i))) | |
37 | b)) | |
38 | (let ((ret (decode-load-program pop))) | |
39 | (if (= i size) | |
40 | (values ret env) | |
41 | (error "bad bytecode: only decoded ~a out of ~a bytes" i size))))) | |
42 | ||
6fe6a2a2 AW |
43 | (define (br-instruction? x) |
44 | (memq x '(br br-if br-if-not br-if-eq br-if-not-eq br-if-null br-if-not-null))) | |
8b652112 AW |
45 | (define (br-nargs-instruction? x) |
46 | (memq x '(br-if-nargs-ne br-if-nargs-lt br-if-nargs-gt))) | |
6fe6a2a2 | 47 | |
97fcf583 AW |
48 | (define (bytes->s24 a b c) |
49 | (let ((x (+ (ash a 16) (ash b 8) c))) | |
50 | (if (zero? (logand (ash 1 23) x)) | |
6fe6a2a2 | 51 | x |
97fcf583 | 52 | (- x (ash 1 24))))) |
6fe6a2a2 | 53 | |
ccf77d95 | 54 | ;; FIXME: this is a little-endian disassembly!!! |
7b107cce | 55 | (define (decode-load-program pop) |
56164a5a | 56 | (let* ((a (pop)) (b (pop)) (c (pop)) (d (pop)) |
9aeaabdc | 57 | (e (pop)) (f (pop)) (g (pop)) (h (pop)) |
7b107cce | 58 | (len (+ a (ash b 8) (ash c 16) (ash d 24))) |
9aeaabdc | 59 | (metalen (+ e (ash f 8) (ash g 16) (ash h 24))) |
6fe6a2a2 | 60 | (labels '()) |
7b107cce | 61 | (i 0)) |
97fcf583 AW |
62 | (define (ensure-label rel1 rel2 rel3) |
63 | (let ((where (+ i (bytes->s24 rel1 rel2 rel3)))) | |
6fe6a2a2 AW |
64 | (or (assv-ref labels where) |
65 | (begin | |
66 | (let ((l (gensym ":L"))) | |
67 | (set! labels (acons where l labels)) | |
68 | l))))) | |
7b107cce | 69 | (define (sub-pop) ;; ...records. ha. ha. |
1f1ec13b AW |
70 | (let ((b (cond ((< i len) (pop)) |
71 | ((= i len) #f) | |
7b107cce AW |
72 | (else (error "tried to decode too many bytes"))))) |
73 | (if b (set! i (1+ i))) | |
74 | b)) | |
75 | (let lp ((out '())) | |
1f1ec13b | 76 | (cond ((> i len) |
7b107cce | 77 | (error "error decoding program -- read too many bytes" out)) |
1f1ec13b | 78 | ((= i len) |
56164a5a | 79 | `(load-program ,(map (lambda (x) (cons (cdr x) (car x))) |
6fe6a2a2 AW |
80 | (reverse labels)) |
81 | ,len | |
1f1ec13b | 82 | ,(if (zero? metalen) #f (decode-load-program pop)) |
7b107cce AW |
83 | ,@(reverse! out))) |
84 | (else | |
85 | (let ((exp (decode-bytecode sub-pop))) | |
6fe6a2a2 | 86 | (pmatch exp |
97fcf583 AW |
87 | ((,br ,rel1 ,rel2 ,rel3) (guard (br-instruction? br)) |
88 | (lp (cons `(,br ,(ensure-label rel1 rel2 rel3)) out))) | |
8b652112 AW |
89 | ((,br ,hi ,lo ,rel1 ,rel2 ,rel3) (guard (br-nargs-instruction? br)) |
90 | (lp (cons `(,br ,hi ,lo ,(ensure-label rel1 rel2 rel3)) out))) | |
97fcf583 | 91 | ((mv-call ,n ,rel1 ,rel2 ,rel3) |
3c365b8e | 92 | (lp (cons `(mv-call ,n ,(ensure-label rel1 rel2 rel3)) out))) |
9b7ca73c AW |
93 | ((prompt ,n0 ,n1 ,rel1 ,rel2 ,rel3) |
94 | (lp (cons `(prompt ,n0 ,n1 ,(ensure-label rel1 rel2 rel3)) out))) | |
6fe6a2a2 AW |
95 | (else |
96 | (lp (cons exp out)))))))))) | |
7b107cce AW |
97 | |
98 | (define (decode-bytecode pop) | |
99 | (and=> (pop) | |
100 | (lambda (opcode) | |
101 | (let ((inst (opcode->instruction opcode))) | |
102 | (cond | |
103 | ((eq? inst 'load-program) | |
104 | (decode-load-program pop)) | |
6cf48307 | 105 | |
7b107cce | 106 | ((< (instruction-length inst) 0) |
6cf48307 MG |
107 | ;; the negative length indicates a variable length |
108 | ;; instruction | |
15939985 | 109 | (let* ((make-sequence |
94ff26b9 | 110 | (if (or (memq inst '(load-array load-wide-string))) |
15939985 LC |
111 | make-bytevector |
112 | make-string)) | |
113 | (sequence-set! | |
94ff26b9 | 114 | (if (or (memq inst '(load-array load-wide-string))) |
15939985 LC |
115 | bytevector-u8-set! |
116 | (lambda (str pos value) | |
117 | (string-set! str pos (integer->char value))))) | |
15939985 | 118 | (len (let* ((a (pop)) (b (pop)) (c (pop))) |
8403b9f5 | 119 | (+ (ash a 16) (ash b 8) c))) |
15939985 | 120 | (seq (make-sequence len))) |
7b107cce AW |
121 | (let lp ((i 0)) |
122 | (if (= i len) | |
94ff26b9 | 123 | `(,inst ,(if (eq? inst 'load-wide-string) |
b158c2c3 | 124 | (utf32->string seq (native-endianness)) |
94ff26b9 | 125 | seq)) |
7b107cce | 126 | (begin |
94ff26b9 | 127 | (sequence-set! seq i (pop)) |
7b107cce AW |
128 | (lp (1+ i))))))) |
129 | (else | |
130 | ;; fixed length | |
131 | (let lp ((n (instruction-length inst)) (out (list inst))) | |
132 | (if (zero? n) | |
133 | (reverse! out) | |
134 | (lp (1- n) (cons (pop) out)))))))))) |