about summary refs log tree commit diff stats
path: root/html/074deep_copy.cc.html
blob: bd40721c81c6fbe82ba21190c35cdefe8731b1af (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Mu - 074deep_copy.cc</title>
<meta name="Generator" content="Vim/7.4">
<meta name="plugin-version" content="vim7.4_v2">
<meta name="syntax" content="cpp">
<meta name="settings" content="use_css,pre_wrap,no_foldcolumn,expand_tabs,prevent_copy=">
<meta name="colorscheme" content="minimal">
<style type="text/css">
<!--
pre { white-space: pre-wrap; font-family: monospace; color: #eeeeee; background-color: #080808; }
body { font-size: 12pt; font-family: monospace; color: #eeeeee; background-color: #080808; }
* { font-size: 12pt; font-size: 1em; }
.Constant { color: #00a0a0; }
.cSpecial { color: #008000; }
.traceContains { color: #008000; }
.Comment { color: #9090ff; }
.Delimiter { color: #800080; }
.Special { color: #c00000; }
.Identifier { color: #fcb165; }
.Normal { color: #eeeeee; background-color: #080808; padding-bottom: 1px; }
-->
</style>

<script type='text/javascript'>
<!--

-->
</script>
</head>
<body>
<pre id='vimCodeElement'>
<span class="Comment">// To recursively copy containers and any addresses they contain, use</span>
<span class="Comment">// 'deep-copy'.</span>
<span class="Comment">//</span>
<span class="Comment">// Invariant: After a deep-copy its ingredient and result will point to no</span>
<span class="Comment">// common addresses.</span>
<span class="Comment">// Implications: Refcounts of all data pointed to by the original ingredient</span>
<span class="Comment">// will remain unchanged. Refcounts of all data pointed to by the (newly</span>
<span class="Comment">// created) result will be 1, in the absence of cycles.</span>
<span class="Comment">//</span>
<span class="Comment">// We do handle cycles in the ingredient, however. All cycles are translated</span>
<span class="Comment">// to new cycles in the product.</span>

<span class="Delimiter">:(scenario deep_copy_number)</span>
def main [
  local-scope
  <span class="Normal">x</span>:num<span class="Special"> &lt;- </span>copy <span class="Constant">34</span>
  <span class="Normal">y</span>:num<span class="Special"> &lt;- </span>deep-copy x
  <span class="Constant">10</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal x<span class="Delimiter">,</span> y
]
<span class="Comment"># non-address primitives are identical</span>
<span class="traceContains">+mem: storing 1 in location 10</span>

<span class="Delimiter">:(scenario deep_copy_container_without_address)</span>
container foo [
  <span class="Normal">x</span>:num
  <span class="Normal">y</span>:num
]
def main [
  local-scope
  <span class="Normal">a</span>:foo<span class="Special"> &lt;- </span>merge <span class="Constant">34</span><span class="Delimiter">,</span> <span class="Constant">35</span>
  <span class="Normal">b</span>:foo<span class="Special"> &lt;- </span>deep-copy a
  <span class="Constant">10</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal a<span class="Delimiter">,</span> b
]
<span class="Comment"># containers are identical as long as they don't contain addresses</span>
<span class="traceContains">+mem: storing 1 in location 10</span>

<span class="Delimiter">:(scenario deep_copy_address)</span>
<span class="Special">% Memory_allocated_until = 200;</span>
def main [
  <span class="Comment"># avoid all memory allocations except the implicit ones inside deep-copy, so</span>
  <span class="Comment"># that the result is deterministic</span>
  <span class="Constant">1</span>:&amp;:num<span class="Special"> &lt;- </span>copy <span class="Constant">100</span>/unsafe  <span class="Comment"># pretend allocation</span>
  *<span class="Constant">1</span>:&amp;:num<span class="Special"> &lt;- </span>copy <span class="Constant">34</span>
  <span class="Constant">2</span>:&amp;:num<span class="Special"> &lt;- </span>deep-copy <span class="Constant">1</span>:&amp;:num
  <span class="Constant">10</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal <span class="Constant">1</span>:&amp;:num<span class="Delimiter">,</span> <span class="Constant">2</span>:&amp;:num
  <span class="Constant">11</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal *<span class="Constant">1</span>:&amp;:num<span class="Delimiter">,</span> *<span class="Constant">2</span>:&amp;:num
  <span class="Constant">2</span>:&amp;:num<span class="Special"> &lt;- </span>copy <span class="Constant">0</span>
]
<span class="Comment"># the result of deep-copy is a new address</span>
<span class="traceContains">+mem: storing 0 in location 10</span>
<span class="Comment"># however, the contents are identical</span>
<span class="traceContains">+mem: storing 1 in location 11</span>
<span class="Comment"># the result of deep-copy gets a refcount of 1</span>
<span class="Comment"># (its address 202 = 200 base + 2 for temporary space inside deep-copy)</span>
<span class="traceContains">+run: {2: (&quot;address&quot; &quot;number&quot;)} &lt;- copy {0: &quot;literal&quot;}</span>
<span class="traceContains">+mem: decrementing refcount of 202: 1 -&gt; 0</span>
<span class="traceContains">+abandon: saving 202 in free-list of size 2</span>

<span class="Delimiter">:(scenario deep_copy_address_to_container)</span>
<span class="Special">% Memory_allocated_until = 200;</span>
def main [
  <span class="Comment"># avoid all memory allocations except the implicit ones inside deep-copy, so</span>
  <span class="Comment"># that the result is deterministic</span>
  <span class="Constant">1</span>:&amp;:point<span class="Special"> &lt;- </span>copy <span class="Constant">100</span>/unsafe  <span class="Comment"># pretend allocation</span>
  *<span class="Constant">1</span>:&amp;:point<span class="Special"> &lt;- </span>merge <span class="Constant">34</span><span class="Delimiter">,</span> <span class="Constant">35</span>
  <span class="Constant">2</span>:&amp;:point<span class="Special"> &lt;- </span>deep-copy <span class="Constant">1</span>:&amp;:point
  <span class="Constant">10</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal <span class="Constant">1</span>:&amp;:point<span class="Delimiter">,</span> <span class="Constant">2</span>:&amp;:point
  <span class="Constant">11</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal *<span class="Constant">1</span>:&amp;:point<span class="Delimiter">,</span> *<span class="Constant">2</span>:&amp;:point
]
<span class="Comment"># the result of deep-copy is a new address</span>
<span class="traceContains">+mem: storing 0 in location 10</span>
<span class="Comment"># however, the contents are identical</span>
<span class="traceContains">+mem: storing 1 in location 11</span>

<span class="Delimiter">:(scenario deep_copy_address_to_address)</span>
<span class="Special">% Memory_allocated_until = 200;</span>
def main [
  <span class="Comment"># avoid all memory allocations except the implicit ones inside deep-copy, so</span>
  <span class="Comment"># that the result is deterministic</span>
  <span class="Constant">1</span>:&amp;:&amp;:num<span class="Special"> &lt;- </span>copy <span class="Constant">100</span>/unsafe  <span class="Comment"># pretend allocation</span>
  *<span class="Constant">1</span>:&amp;:&amp;:num<span class="Special"> &lt;- </span>copy <span class="Constant">150</span>/unsafe
  **<span class="Constant">1</span>:&amp;:&amp;:num<span class="Special"> &lt;- </span>copy <span class="Constant">34</span>
  <span class="Constant">2</span>:&amp;:&amp;:num<span class="Special"> &lt;- </span>deep-copy <span class="Constant">1</span>:&amp;:&amp;:num
  <span class="Constant">10</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal <span class="Constant">1</span>:&amp;:&amp;:num<span class="Delimiter">,</span> <span class="Constant">2</span>:&amp;:&amp;:num
  <span class="Constant">11</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal *<span class="Constant">1</span>:&amp;:&amp;:num<span class="Delimiter">,</span> *<span class="Constant">2</span>:&amp;:&amp;:num
  <span class="Constant">12</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal **<span class="Constant">1</span>:&amp;:&amp;:num<span class="Delimiter">,</span> **<span class="Constant">2</span>:&amp;:&amp;:num
]
<span class="Comment"># the result of deep-copy is a new address</span>
<span class="traceContains">+mem: storing 0 in location 10</span>
<span class="Comment"># any addresses in it or pointed to it are also new</span>
<span class="traceContains">+mem: storing 0 in location 11</span>
<span class="Comment"># however, the non-address contents are identical</span>
<span class="traceContains">+mem: storing 1 in location 12</span>

<span class="Delimiter">:(scenario deep_copy_array)</span>
<span class="Special">% Memory_allocated_until = 200;</span>
def main [
  <span class="Comment"># avoid all memory allocations except the implicit ones inside deep-copy, so</span>
  <span class="Comment"># that the result is deterministic</span>
  <span class="Constant">100</span>:num<span class="Special"> &lt;- </span>copy <span class="Constant">1</span>  <span class="Comment"># pretend refcount</span>
  <span class="Constant">101</span>:num<span class="Special"> &lt;- </span>copy <span class="Constant">3</span>  <span class="Comment"># pretend array length</span>
  <span class="Constant">1</span>:&amp;:@:num<span class="Special"> &lt;- </span>copy <span class="Constant">100</span>/unsafe  <span class="Comment"># pretend allocation</span>
  put-index *<span class="Constant">1</span>:&amp;:@:num<span class="Delimiter">,</span> <span class="Constant">0</span><span class="Delimiter">,</span> <span class="Constant">34</span>
  put-index *<span class="Constant">1</span>:&amp;:@:num<span class="Delimiter">,</span> <span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">35</span>
  put-index *<span class="Constant">1</span>:&amp;:@:num<span class="Delimiter">,</span> <span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">36</span>
  stash [old:]<span class="Delimiter">,</span> *<span class="Constant">1</span>:&amp;:@:num
  <span class="Constant">2</span>:&amp;:@:num<span class="Special"> &lt;- </span>deep-copy <span class="Constant">1</span>:&amp;:@:num
  stash <span class="Constant">2</span>:&amp;:@:num
  stash [<span class="Normal">new</span>:]<span class="Delimiter">,</span> *<span class="Constant">2</span>:&amp;:@:num
  <span class="Constant">10</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal <span class="Constant">1</span>:&amp;:@:num<span class="Delimiter">,</span> <span class="Constant">2</span>:&amp;:@:num
  <span class="Constant">11</span>:<span class="Normal">bool</span><span class="Special"> &lt;- </span>equal *<span class="Constant">1</span>:&amp;:@:num<span class="Delimiter">,</span> *<span class="Constant">2</span>:&amp;:@:num
]
<span class="traceContains">+app: old: 3 34 35 36</span>
<span class="traceContains">+app: new: 3 34 35 36</span>
<span class="Comment"># the result of deep-copy is a new address</span>
<span class="traceContains">+mem: storing 0 in location 10</span>
<span class="Comment"># however, the contents are identical</span>
<span class="traceContains">+mem: storing 1 in location 11</span>

<span class="Delimiter">:(scenario deep_copy_container_with_address)</span>
container foo [
  <span class="Normal">x</span>:num
  <span class="Normal">y</span>:&amp;:num
]
def main [
  local-scope
  <span class="Normal">y0</span>:&amp;:num<span class="Special"> &lt;- </span><span class="Normal">new</span> number:type
  *y0<span class="Special"> &lt;- </span>copy <span class="Constant">35</span>
  <span class="Normal">a</span>:foo<span class="Special"> &lt;- </span>merge <span class="Constant">34</span><span class="Delimiter">,</span> y0
  <span class="Normal">b</span>:foo<span class="Special"> &lt;- </span>deep-copy a
  <span class="Constant">10</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal a<span class="Delimiter">,</span> b
  <span class="Normal">y1</span>:&amp;:num<span class="Special"> &lt;- </span>get b<span class="Delimiter">,</span> y:offset
  <span class="Constant">11</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal y0<span class="Delimiter">,</span> y1
  <span class="Constant">12</span>:num/<span class="Special">raw &lt;- </span>copy *y1
]
<span class="Comment"># containers containing addresses are not identical to their deep copies</span>
<span class="traceContains">+mem: storing 0 in location 10</span>
<span class="Comment"># the addresses they contain are not identical either</span>
<span class="traceContains">+mem: storing 0 in location 11</span>
<span class="traceContains">+mem: storing 35 in location 12</span>

<span class="Delimiter">:(scenario deep_copy_exclusive_container_with_address)</span>
exclusive-container foo [
  <span class="Normal">x</span>:num
  <span class="Normal">y</span>:&amp;:num
]
def main [
  local-scope
  <span class="Normal">y0</span>:&amp;:num<span class="Special"> &lt;- </span><span class="Normal">new</span> number:type
  *y0<span class="Special"> &lt;- </span>copy <span class="Constant">34</span>
  <span class="Normal">a</span>:foo<span class="Special"> &lt;- </span>merge <span class="Constant">1</span>/y<span class="Delimiter">,</span> y0
  <span class="Normal">b</span>:foo<span class="Special"> &lt;- </span>deep-copy a
  <span class="Constant">10</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal a<span class="Delimiter">,</span> b
  <span class="Normal">y1</span>:&amp;:num<span class="Delimiter">,</span> z:<span class="Normal">bool</span><span class="Special"> &lt;- </span>maybe-convert b<span class="Delimiter">,</span> y:variant
  <span class="Constant">11</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal y0<span class="Delimiter">,</span> y1
  <span class="Constant">12</span>:num/<span class="Special">raw &lt;- </span>copy *y1
]
<span class="Comment"># exclusive containers containing addresses are not identical to their deep copies</span>
<span class="traceContains">+mem: storing 0 in location 10</span>
<span class="Comment"># the addresses they contain are not identical either</span>
<span class="traceContains">+mem: storing 0 in location 11</span>
<span class="traceContains">+mem: storing 34 in location 12</span>

<span class="Delimiter">:(scenario deep_copy_exclusive_container_with_container_with_address)</span>
exclusive-container foo [
  <span class="Normal">x</span>:num
  <span class="Normal">y</span>:bar  <span class="Comment"># inline</span>
]
container bar [
  <span class="Normal">x</span>:&amp;:num
]
def main [
  local-scope
  <span class="Normal">y0</span>:&amp;:num<span class="Special"> &lt;- </span><span class="Normal">new</span> number:type
  *y0<span class="Special"> &lt;- </span>copy <span class="Constant">34</span>
  <span class="Normal">a</span>:bar<span class="Special"> &lt;- </span>merge y0
  <span class="Normal">b</span>:foo<span class="Special"> &lt;- </span>merge <span class="Constant">1</span>/y<span class="Delimiter">,</span> a
  <span class="Normal">c</span>:foo<span class="Special"> &lt;- </span>deep-copy b
  <span class="Constant">10</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal b<span class="Delimiter">,</span> c
  <span class="Normal">d</span>:bar<span class="Delimiter">,</span> z:<span class="Normal">bool</span><span class="Special"> &lt;- </span>maybe-convert c<span class="Delimiter">,</span> y:variant
  <span class="Normal">y1</span>:&amp;:num<span class="Special"> &lt;- </span>get d<span class="Delimiter">,</span> x:offset
  <span class="Constant">11</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal y0<span class="Delimiter">,</span> y1
  <span class="Constant">12</span>:num/<span class="Special">raw &lt;- </span>copy *y1
]
<span class="Comment"># exclusive containers containing addresses are not identical to their deep copies</span>
<span class="traceContains">+mem: storing 0 in location 10</span>
<span class="Comment"># sub-containers containing addresses are not identical either</span>
<span class="traceContains">+mem: storing 0 in location 11</span>
<span class="traceContains">+mem: storing 34 in location 12</span>

<span class="Delimiter">:(before &quot;End Primitive Recipe Declarations&quot;)</span>
DEEP_COPY<span class="Delimiter">,</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Numbers&quot;)</span>
put<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;deep-copy&quot;</span><span class="Delimiter">,</span> DEEP_COPY<span class="Delimiter">);</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Checks&quot;)</span>
<span class="Normal">case</span> DEEP_COPY: <span class="Delimiter">{</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">)</span> != <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    raise &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'deep-copy' takes exactly one ingredient rather than '&quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>original_string &lt;&lt; <span class="Constant">&quot;'</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>products<span class="Delimiter">)</span> != <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    raise &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'deep-copy' takes exactly one ingredient rather than '&quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>original_string &lt;&lt; <span class="Constant">&quot;'</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>!types_strictly_match<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">),</span> inst<span class="Delimiter">.</span>products<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    raise &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'deep-copy' requires its ingredient and product to be the same type, but got '&quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>original_string &lt;&lt; <span class="Constant">&quot;'</span><span class="cSpecial">\n</span><span class="Constant">&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Implementations&quot;)</span>
<span class="Normal">case</span> DEEP_COPY: <span class="Delimiter">{</span>
  <span class="Normal">const</span> reagent&amp; input = current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">);</span>
  <span class="Comment">// allocate a tiny bit of temporary space for deep_copy()</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: allocating space for temporary&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
  reagent tmp<span class="Delimiter">(</span><span class="Constant">&quot;tmp:address:number&quot;</span><span class="Delimiter">);</span>
  tmp<span class="Delimiter">.</span>set_value<span class="Delimiter">(</span>allocate<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">));</span>
  products<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>deep_copy<span class="Delimiter">(</span>input<span class="Delimiter">,</span> tmp<span class="Delimiter">));</span>
  <span class="Comment">// reclaim Mu memory allocated for tmp</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: reclaiming temporary&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
  abandon<span class="Delimiter">(</span>tmp<span class="Delimiter">.</span>value<span class="Delimiter">,</span> tmp<span class="Delimiter">.</span>type<span class="Delimiter">-&gt;</span>right<span class="Delimiter">,</span> payload_size<span class="Delimiter">(</span>tmp<span class="Delimiter">));</span>
  <span class="Comment">// reclaim host memory allocated for tmp.type when tmp goes out of scope</span>
  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(code)</span>
vector&lt;<span class="Normal">double</span>&gt; deep_copy<span class="Delimiter">(</span><span class="Normal">const</span> reagent&amp; in<span class="Delimiter">,</span> <span class="Normal">const</span> reagent&amp; tmp<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  map&lt;<span class="Normal">int</span><span class="Delimiter">,</span> <span class="Normal">int</span>&gt; addresses_copied<span class="Delimiter">;</span>
  <span class="Identifier">return</span> deep_copy<span class="Delimiter">(</span>in<span class="Delimiter">,</span> addresses_copied<span class="Delimiter">,</span> tmp<span class="Delimiter">);</span>
<span class="Delimiter">}</span>

vector&lt;<span class="Normal">double</span>&gt; deep_copy<span class="Delimiter">(</span>reagent<span class="Comment">/*</span><span class="Comment">copy</span><span class="Comment">*/</span> in<span class="Delimiter">,</span> map&lt;<span class="Normal">int</span><span class="Delimiter">,</span> <span class="Normal">int</span>&gt;&amp; addresses_copied<span class="Delimiter">,</span> <span class="Normal">const</span> reagent&amp; tmp<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  canonize<span class="Delimiter">(</span>in<span class="Delimiter">);</span>
  vector&lt;<span class="Normal">double</span>&gt; result<span class="Delimiter">;</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>is_mu_address<span class="Delimiter">(</span>in<span class="Delimiter">))</span>
    result<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>deep_copy_address<span class="Delimiter">(</span>in<span class="Delimiter">,</span> addresses_copied<span class="Delimiter">,</span> tmp<span class="Delimiter">));</span>
  <span class="Normal">else</span>
    deep_copy<span class="Delimiter">(</span>in<span class="Delimiter">,</span> addresses_copied<span class="Delimiter">,</span> tmp<span class="Delimiter">,</span> result<span class="Delimiter">);</span>
  <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">// deep-copy an address and return a new address</span>
<span class="Normal">int</span> deep_copy_address<span class="Delimiter">(</span><span class="Normal">const</span> reagent&amp; canonized_in<span class="Delimiter">,</span> map&lt;<span class="Normal">int</span><span class="Delimiter">,</span> <span class="Normal">int</span>&gt;&amp; addresses_copied<span class="Delimiter">,</span> <span class="Normal">const</span> reagent&amp; tmp<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>canonized_in<span class="Delimiter">.</span>value == <span class="Constant">0</span><span class="Delimiter">)</span> <span class="Identifier">return</span> <span class="Constant">0</span><span class="Delimiter">;</span>
  <span class="Normal">int</span> in_address = payload_address<span class="Delimiter">(</span>canonized_in<span class="Delimiter">);</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: copying address &quot;</span> &lt;&lt; in_address &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>contains_key<span class="Delimiter">(</span>addresses_copied<span class="Delimiter">,</span> in_address<span class="Delimiter">))</span> <span class="Delimiter">{</span>
    <span class="Normal">int</span> out = get<span class="Delimiter">(</span>addresses_copied<span class="Delimiter">,</span> in_address<span class="Delimiter">);</span>
    trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: copy already exists: &quot;</span> &lt;&lt; out &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">return</span> out<span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Normal">int</span> out = allocate<span class="Delimiter">(</span>payload_size<span class="Delimiter">(</span>canonized_in<span class="Delimiter">));</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: new address is &quot;</span> &lt;&lt; out &lt;&lt; end<span class="Delimiter">();</span>
  put<span class="Delimiter">(</span>addresses_copied<span class="Delimiter">,</span> in_address<span class="Delimiter">,</span> out<span class="Delimiter">);</span>
  reagent<span class="Comment">/*</span><span class="Comment">copy</span><span class="Comment">*/</span> payload = canonized_in<span class="Delimiter">;</span>
  payload<span class="Delimiter">.</span>properties<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>pair&lt;string<span class="Delimiter">,</span> string_tree*&gt;<span class="Delimiter">(</span><span class="Constant">&quot;lookup&quot;</span><span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">));</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;recursing on payload &quot;</span> &lt;&lt; payload<span class="Delimiter">.</span>value &lt;&lt; <span class="Constant">' '</span> &lt;&lt; to_string<span class="Delimiter">(</span>payload<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
  vector&lt;<span class="Normal">double</span>&gt; data = deep_copy<span class="Delimiter">(</span>payload<span class="Delimiter">,</span> addresses_copied<span class="Delimiter">,</span> tmp<span class="Delimiter">);</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: writing result &quot;</span> &lt;&lt; out &lt;&lt; <span class="Constant">&quot;: &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>data<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Comment">// HACK: write_memory interface isn't ideal for this situation; we need</span>
  <span class="Comment">// a temporary location to help copy the payload.</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: writing temporary &quot;</span> &lt;&lt; tmp<span class="Delimiter">.</span>value &lt;&lt; <span class="Constant">&quot;: &quot;</span> &lt;&lt; out &lt;&lt; end<span class="Delimiter">();</span>
  put<span class="Delimiter">(</span>Memory<span class="Delimiter">,</span> tmp<span class="Delimiter">.</span>value<span class="Delimiter">,</span> out<span class="Delimiter">);</span>
  payload<span class="Delimiter">.</span>set_value<span class="Delimiter">(</span>tmp<span class="Delimiter">.</span>value<span class="Delimiter">);</span>  <span class="Comment">// now modified for output</span>
  vector&lt;<span class="Normal">double</span>&gt; old_data = read_memory<span class="Delimiter">(</span>payload<span class="Delimiter">);</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: really writing to &quot;</span> &lt;&lt; payload<span class="Delimiter">.</span>value &lt;&lt; <span class="Constant">' '</span> &lt;&lt; to_string<span class="Delimiter">(</span>payload<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot; (old value &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>old_data<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot; new value &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>data<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;)&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
  write_memory<span class="Delimiter">(</span>payload<span class="Delimiter">,</span> data<span class="Delimiter">);</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: output is &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>data<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Identifier">return</span> out<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">// deep-copy a non-address and return a vector of locations</span>
<span class="Normal">void</span> deep_copy<span class="Delimiter">(</span><span class="Normal">const</span> reagent&amp; canonized_in<span class="Delimiter">,</span> map&lt;<span class="Normal">int</span><span class="Delimiter">,</span> <span class="Normal">int</span>&gt;&amp; addresses_copied<span class="Delimiter">,</span> <span class="Normal">const</span> reagent&amp; tmp<span class="Delimiter">,</span> vector&lt;<span class="Normal">double</span>&gt;&amp; out<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  assert<span class="Delimiter">(</span>!is_mu_address<span class="Delimiter">(</span>canonized_in<span class="Delimiter">));</span>
  vector&lt;<span class="Normal">double</span>&gt; data = read_memory<span class="Delimiter">(</span>canonized_in<span class="Delimiter">);</span>
  out<span class="Delimiter">.</span>insert<span class="Delimiter">(</span>out<span class="Delimiter">.</span>end<span class="Delimiter">(),</span> data<span class="Delimiter">.</span>begin<span class="Delimiter">(),</span> data<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
  <span class="Normal">if</span> <span class="Delimiter">(</span>!contains_key<span class="Delimiter">(</span>Container_metadata<span class="Delimiter">,</span> canonized_in<span class="Delimiter">.</span>type<span class="Delimiter">))</span> <span class="Identifier">return</span><span class="Delimiter">;</span>
  trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: scanning for addresses in &quot;</span> &lt;&lt; to_string<span class="Delimiter">(</span>data<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Normal">const</span> container_metadata&amp; metadata = get<span class="Delimiter">(</span>Container_metadata<span class="Delimiter">,</span> canonized_in<span class="Delimiter">.</span>type<span class="Delimiter">);</span>
  <span class="Normal">for</span> <span class="Delimiter">(</span>map&lt;set&lt;tag_condition_info&gt;<span class="Delimiter">,</span> set&lt;address_element_info&gt; &gt;::const_iterator p = metadata<span class="Delimiter">.</span>address<span class="Delimiter">.</span>begin<span class="Delimiter">();</span> p != metadata<span class="Delimiter">.</span>address<span class="Delimiter">.</span>end<span class="Delimiter">();</span> ++p<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Normal">if</span> <span class="Delimiter">(</span>!all_match<span class="Delimiter">(</span>data<span class="Delimiter">,</span> p<span class="Delimiter">-&gt;</span>first<span class="Delimiter">))</span> <span class="Identifier">continue</span><span class="Delimiter">;</span>
    <span class="Normal">for</span> <span class="Delimiter">(</span>set&lt;address_element_info&gt;::const_iterator info = p<span class="Delimiter">-&gt;</span>second<span class="Delimiter">.</span>begin<span class="Delimiter">();</span> info != p<span class="Delimiter">-&gt;</span>second<span class="Delimiter">.</span>end<span class="Delimiter">();</span> ++info<span class="Delimiter">)</span> <span class="Delimiter">{</span>
      <span class="Comment">// construct a fake reagent that reads directly from the appropriate</span>
      <span class="Comment">// field of the container</span>
      reagent curr<span class="Delimiter">;</span>
      curr<span class="Delimiter">.</span>type = <span class="Normal">new</span> type_tree<span class="Delimiter">(</span><span class="Normal">new</span> type_tree<span class="Delimiter">(</span><span class="Constant">&quot;address&quot;</span><span class="Delimiter">),</span> <span class="Normal">new</span> type_tree<span class="Delimiter">(</span>*info<span class="Delimiter">-&gt;</span>payload_type<span class="Delimiter">));</span>
      curr<span class="Delimiter">.</span>set_value<span class="Delimiter">(</span>canonized_in<span class="Delimiter">.</span>value + info<span class="Delimiter">-&gt;</span>offset<span class="Delimiter">);</span>
      curr<span class="Delimiter">.</span>properties<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>pair&lt;string<span class="Delimiter">,</span> string_tree*&gt;<span class="Delimiter">(</span><span class="Constant">&quot;raw&quot;</span><span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">));</span>
      trace<span class="Delimiter">(</span><span class="Constant">9991</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;deep-copy: copying address &quot;</span> &lt;&lt; curr<span class="Delimiter">.</span>value &lt;&lt; end<span class="Delimiter">();</span>
      out<span class="Delimiter">.</span>at<span class="Delimiter">(</span>info<span class="Delimiter">-&gt;</span>offset<span class="Delimiter">)</span> = deep_copy_address<span class="Delimiter">(</span>curr<span class="Delimiter">,</span> addresses_copied<span class="Delimiter">,</span> tmp<span class="Delimiter">);</span>
    <span class="Delimiter">}</span>
  <span class="Delimiter">}</span>
<span class="Delimiter">}</span>

<span class="Normal">int</span> payload_address<span class="Delimiter">(</span>reagent<span class="Comment">/*</span><span class="Comment">copy</span><span class="Comment">*/</span> x<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  x<span class="Delimiter">.</span>properties<span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>pair&lt;string<span class="Delimiter">,</span> string_tree*&gt;<span class="Delimiter">(</span><span class="Constant">&quot;lookup&quot;</span><span class="Delimiter">,</span> <span class="Constant">NULL</span><span class="Delimiter">));</span>
  canonize<span class="Delimiter">(</span>x<span class="Delimiter">);</span>
  <span class="Identifier">return</span> x<span class="Delimiter">.</span>value<span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Comment">//: moar tests, just because I can't believe it all works</span>

<span class="Delimiter">:(scenario deep_copy_stress_test_1)</span>
container foo1 [
  <span class="Normal">p</span>:&amp;:num
]
container foo2 [
  <span class="Normal">p</span>:&amp;:foo1
]
exclusive-container foo3 [
  <span class="Normal">p</span>:&amp;:foo1
  <span class="Normal">q</span>:&amp;:foo2
]
def main [
  local-scope
  <span class="Normal">x</span>:&amp;:num<span class="Special"> &lt;- </span><span class="Normal">new</span> number:type
  *x<span class="Special"> &lt;- </span>copy <span class="Constant">34</span>
  <span class="Normal">a</span>:&amp;:foo1<span class="Special"> &lt;- </span><span class="Normal">new</span> foo1:type
  *a<span class="Special"> &lt;- </span>merge x
  <span class="Normal">b</span>:&amp;:foo2<span class="Special"> &lt;- </span><span class="Normal">new</span> foo2:type
  *b<span class="Special"> &lt;- </span>merge a
  <span class="Normal">c</span>:foo3<span class="Special"> &lt;- </span>merge <span class="Constant">1</span>/q<span class="Delimiter">,</span> b
  <span class="Normal">d</span>:foo3<span class="Special"> &lt;- </span>deep-copy c
  <span class="Normal">e</span>:&amp;:foo2<span class="Delimiter">,</span> z:<span class="Normal">bool</span><span class="Special"> &lt;- </span>maybe-convert d<span class="Delimiter">,</span> q:variant
  <span class="Normal">f</span>:&amp;:foo1<span class="Special"> &lt;- </span>get *e<span class="Delimiter">,</span> p:offset
  <span class="Normal">g</span>:&amp;:num<span class="Special"> &lt;- </span>get *f<span class="Delimiter">,</span> p:offset
  <span class="Constant">1</span>:num/<span class="Special">raw &lt;- </span>copy *g
]
<span class="traceContains">+mem: storing 34 in location 1</span>

<span class="Delimiter">:(scenario deep_copy_stress_test_2)</span>
container foo1 [
  <span class="Normal">p</span>:&amp;:num
]
container foo2 [
  <span class="Normal">p</span>:&amp;:foo1
]
exclusive-container foo3 [
  <span class="Normal">p</span>:&amp;:foo1
  <span class="Normal">q</span>:&amp;:foo2
]
container foo4 [
  <span class="Normal">p</span>:num
  <span class="Normal">q</span>:&amp;:foo3
]
def main [
  local-scope
  <span class="Normal">x</span>:&amp;:num<span class="Special"> &lt;- </span><span class="Normal">new</span> number:type
  *x<span class="Special"> &lt;- </span>copy <span class="Constant">34</span>
  <span class="Normal">a</span>:&amp;:foo1<span class="Special"> &lt;- </span><span class="Normal">new</span> foo1:type
  *a<span class="Special"> &lt;- </span>merge x
  <span class="Normal">b</span>:&amp;:foo2<span class="Special"> &lt;- </span><span class="Normal">new</span> foo2:type
  *b<span class="Special"> &lt;- </span>merge a
  <span class="Normal">c</span>:&amp;:foo3<span class="Special"> &lt;- </span><span class="Normal">new</span> foo3:type
  *c<span class="Special"> &lt;- </span>merge <span class="Constant">1</span>/q<span class="Delimiter">,</span> b
  <span class="Normal">d</span>:foo4<span class="Special"> &lt;- </span>merge <span class="Constant">35</span><span class="Delimiter">,</span> c
  <span class="Normal">e</span>:foo4<span class="Special"> &lt;- </span>deep-copy d
  <span class="Normal">f</span>:&amp;:foo3<span class="Special"> &lt;- </span>get e<span class="Delimiter">,</span> q:offset
  <span class="Normal">g</span>:&amp;:foo2<span class="Delimiter">,</span> z:<span class="Normal">bool</span><span class="Special"> &lt;- </span>maybe-convert *f<span class="Delimiter">,</span> q:variant
  <span class="Normal">h</span>:&amp;:foo1<span class="Special"> &lt;- </span>get *g<span class="Delimiter">,</span> p:offset
  <span class="Normal">y</span>:&amp;:num<span class="Special"> &lt;- </span>get *h<span class="Delimiter">,</span> p:offset
  <span class="Constant">1</span>:num/<span class="Special">raw &lt;- </span>copy *y
]
<span class="traceContains">+mem: storing 34 in location 1</span>

<span class="Delimiter">:(scenario deep_copy_cycles)</span>
container foo [
  <span class="Normal">p</span>:num
  <span class="Normal">q</span>:&amp;:foo
]
def main [
  local-scope
  <span class="Normal">x</span>:&amp;:foo<span class="Special"> &lt;- </span><span class="Normal">new</span> foo:type
  *x<span class="Special"> &lt;- </span>put *x<span class="Delimiter">,</span> p:offset<span class="Delimiter">,</span> <span class="Constant">34</span>
  *x<span class="Special"> &lt;- </span>put *x<span class="Delimiter">,</span> q:offset<span class="Delimiter">,</span> x  <span class="Comment"># create a cycle</span>
  <span class="Normal">y</span>:&amp;:foo<span class="Special"> &lt;- </span>deep-copy x
  <span class="Constant">1</span>:num/<span class="Special">raw &lt;- </span>get *y<span class="Delimiter">,</span> p:offset
  <span class="Normal">y2</span>:&amp;:foo<span class="Special"> &lt;- </span>get *y<span class="Delimiter">,</span> q:offset
  stash y [vs] y2
  <span class="Constant">2</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal y<span class="Delimiter">,</span> y2  <span class="Comment"># is it still a cycle?</span>
  <span class="Constant">3</span>:<span class="Normal">bool</span>/<span class="Special">raw &lt;- </span>equal x<span class="Delimiter">,</span> y  <span class="Comment"># is it the same cycle?</span>
]
<span class="traceContains">+mem: storing 34 in location 1</span>
<span class="Comment"># deep copy also contains a cycle</span>
<span class="traceContains">+mem: storing 1 in location 2</span>
<span class="Comment"># but it's a completely different (disjoint) cycle</span>
<span class="traceContains">+mem: storing 0 in location 3</span>
</pre>
</body>
</html>
<!-- vim: set foldmethod=manual : -->