1 //: Spaces help isolate recipes from each other. You can create them at will,
  2 //: and all addresses in arguments are implicitly based on the 'default-space'
  3 //: (unless they have the /raw property)
  4 
  5 //: A space is just an array of any scalar location.
  6 :(before "End Mu Types Initialization")
  7 put(Type_abbreviations, "space", new_type_tree("address:array:location"));
  8 //: Spaces are often called 'scopes' in other languages.
  9 put(Type_abbreviations, "scope", new_type_tree("address:array:location"));
 10 
 11 :(scenario set_default_space)
 12 # if default-space is 10, and if an array of 5 locals lies from location 12 to 16 (inclusive),
 13 # then local 0 is really location 12, local 1 is really location 13, and so on.
 14 def main [
 15   # pretend address:array:location; in practice we'll use new
 16   10:num <- copy 0  # refcount
 17   11:num <- copy 5  # length
 18   default-space:space <- copy 10/unsafe
 19   1:num <- copy 23
 20 ]
 21 +mem: storing 23 in location 13
 22 
 23 :(scenario lookup_sidesteps_default_space)
 24 def main [
 25   # pretend pointer from outside (2000 reserved for refcount)
 26   2001:num <- copy 34
 27   # pretend address:array:location; in practice we'll use new
 28   1000:num <- copy 0  # refcount
 29   1001:num <- copy 5  # length
 30   # actual start of this recipe
 31   default-space:space <- copy 1000/unsafe
 32   1:&:num <- copy 2000/unsafe  # even local variables always contain raw addresses
 33   8:num/raw <- copy *1:&:num
 34 ]
 35 +mem: storing 34 in location 8
 36 
 37 //:: first disable name conversion for 'default-space'
 38 :(scenario convert_names_passes_default_space)
 39 % Hide_errors = true;
 40 def main [
 41   default-space:num, x:num <- copy 0, 1
 42 ]
 43 +name: assign x 1
 44 -name: assign default-space 1
 45 
 46 :(before "End is_disqualified Special-cases")
 47 if (x.name == "default-space")
 48   x.initialized = true;
 49 :(before "End is_special_name Special-cases")
 50 if (s == "default-space") return true;
 51 
 52 //:: now implement space support
 53 :(before "End call Fields")
 54 int default_space;
 55 :(before "End call Constructor")
 56 default_space = 0;
 57 
 58 :(before "End canonize(x) Special-cases")
 59 absolutize(x);
 60 :(code)
 61 void absolutize(reagent& x) {
 62   if (is_raw(x) || is_dummy(x)) return;
 63   if (x.name == "default-space") return;
 64   if (!x.initialized)
 65     raise << to_original_string(current_instruction()) << ": reagent not initialized: '" << x.original_string << "'\n" << end();
 66   x.set_value(address(x.value, space_base(x)));
 67   x.properties.push_back(pair<string, string_tree*>("raw", NULL));
 68   assert(is_raw(x));
 69 }
 70 
 71 //: hook replaced in a later layer
 72 int space_base(const reagent& x) {
 73   return current_call().default_space ? (current_call().default_space+/*skip refcount*/1) : 0;
 74 }
 75 
 76 int address(int offset, int base) {
 77   assert(offset >= 0);
 78   if (base == 0) return offset;  // raw
 79   int size = get_or_insert(Memory, base);
 80   if (offset >= size) {
 81     // todo: test
 82     raise << "location " << offset << " is out of bounds " << size << " at " << base << '\n' << end();
 83     return 0;
 84   }
 85   return base + /*skip length*/1 + offset;
 86 }
 87 
 88 //:: reads and writes to the 'default-space' variable have special behavior
 89 
 90 :(after "Begin Preprocess write_memory(x, data)")
 91 if (x.name == "default-space") {
 92   if (!scalar(data) || !is_space(x))
 93     raise << maybe(current_recipe_name()) << "'default-space' should be of type address:array:location, but is " << to_string(x.type) << '\n' << end();
 94   current_call().default_space = data.at(0);
 95   return;
 96 }
 97 :(code)
 98 bool is_space(const reagent& r) {
 99   return is_address_of_array_of_numbers(r);
100 }
101 
102 :(scenario get_default_space)
103 def main [
104   default-space:space <- copy 10/unsafe
105   1:space/raw <- copy default-space:space
106 ]
107 +mem: storing 10 in location 1
108 
109 :(after "Begin Preprocess read_memory(x)")
110 if (x.name == "default-space") {
111   vector<double> result;
112   result.push_back(current_call().default_space);
113   return result;
114 }
115 
116 //:: fix 'get'
117 
118 :(scenario lookup_sidesteps_default_space_in_get)
119 def main [
120   # pretend pointer to container from outside (2000 reserved for refcount)
121   2001:num <- copy 34
122   2002:num <- copy 35
123   # pretend address:array:location; in practice we'll use new
124   1000:num <- copy 0  # refcount
125   1001:num <- copy 5  # length
126   # actual start of this recipe
127   default-space:space <- copy 1000/unsafe
128   1:&:point <- copy 2000/unsafe
129   9:num/raw <- get *1:&:point, 1:offset
130 ]
131 +mem: storing 35 in location 9
132 
133 :(before "Read element" following "case GET:")
134 element.properties.push_back(pair<string, string_tree*>("raw", NULL));
135 
136 //:: fix 'index'
137 
138 :(scenario lookup_sidesteps_default_space_in_index)
139 def main [
140   # pretend pointer to array from outside (2000 reserved for refcount)
141   2001:num <- copy 2  # length
142   2002:num <- copy 34
143   2003:num <- copy 35
144   # pretend address:array:location; in practice we'll use new
145   1000:num <- copy 0  # refcount
146   1001:num <- copy 5  # length
147   # actual start of this recipe
148   default-space:space <- copy 1000/unsafe
149   1:&:@:num <- copy 2000/unsafe
150   9:num/raw <- index *1:&:@:num, 1
151 ]
152 +mem: storing 35 in location 9
153 
154 :(before "Read element" following "case INDEX:")
155 element.properties.push_back(pair<string, string_tree*>("raw", NULL));
156 
157 //:: convenience operation to automatically deduce the amount of space to
158 //:: allocate in a default space with names
159 
160 :(scenario new_default_space)
161 def main [
162   new-default-space
163   x:num <- copy 0
164   y:num <- copy 3
165 ]
166 # allocate space for x and y, as well as the chaining slot at 0
167 +mem: array length is 3
168 
169 :(before "End is_disqualified Special-cases")
170 if (x.name == "number-of-locals")
171   x.initialized = true;
172 :(before "End is_special_name Special-cases")
173 if (s == "number-of-locals") return true;
174 
175 :(before "End Rewrite Instruction(curr, recipe result)")
176 // rewrite `new-default-space` to
177 //   `default-space:space <- new location:type, number-of-locals:literal`
178 // where N is Name[recipe][""]
179 if (curr.name == "new-default-space") {
180   rewrite_default_space_instruction(curr);
181 }
182 :(after "Begin Preprocess read_memory(x)")
183 if (x.name == "number-of-locals") {
184   vector<double> result;
185   result.push_back(Name[get(Recipe_ordinal, current_recipe_name())][""]);
186   if (result.back() == 0)
187     raise << "no space allocated for default-space in recipe " << current_recipe_name() << "; are you using names?\n" << end();
188   return result;
189 }
190 :(after "Begin Preprocess write_memory(x, data)")
191 if (x.name == "number-of-locals") {
192   raise << maybe(current_recipe_name()) << "can't write to special name 'number-of-locals'\n" << end();
193   return;
194 }
195 
196 //:: 'local-scope' is like 'new-default-space' except that we'll reclaim the
197 //:: default-space when the routine exits
198 
199 :(scenario local_scope)
200 def main [
201   1:&:@:location <- foo
202   2:&:@:location <- foo
203   3:bool <- equal 1:&, 2:&
204 ]
205 def foo [
206   local-scope
207   x:num <- copy 34
208   return default-space:space
209 ]
210 # both calls to foo should have received the same default-space
211 +mem: storing 1 in location 3
212 
213 :(scenario local_scope_frees_up_addresses)
214 def main [
215   local-scope
216   x:text <- new [abc]
217 ]
218 +mem: clearing x:text
219 
220 :(before "End Rewrite Instruction(curr, recipe result)")
221 if (curr.name == "local-scope") {
222   rewrite_default_space_instruction(curr);
223 }
224 
225 //: todo: do this in a transform, rather than magically in the 'return' instruction
226 :(after "Falling Through End Of Recipe")
227 try_reclaim_locals();
228 :(after "Starting Reply")
229 try_reclaim_locals();
230 
231 :(code)
232 void try_reclaim_locals() {
233   // only reclaim routines starting with 'local-scope'
234   const recipe_ordinal r = get(Recipe_ordinal, current_recipe_name());
235   const recipe& exiting_recipe = get(Recipe, r);
236   if (exiting_recipe.steps.empty()) return;
237   const instruction& inst = exiting_recipe.steps.at(0);
238   if (inst.name_before_rewrite != "local-scope") return;
239   // reclaim any local variables unless they're being returned
240   vector<double> zeros;
241   for (int i = /*leave default space for last*/1;  i < SIZE(exiting_recipe.steps);  ++i) {
242     const instruction& inst = exiting_recipe.steps.at(i);
243     for (int i = 0;  i < SIZE(inst.products);  ++i) {
244       const reagent& product = inst.products.at(i);
245       // local variables only
246       if (has_property(product, "lookup")) continue;
247       if (has_property(product, "raw")) continue;  // tests often want to check such locations after they run
248       if (escaping(product)) continue;
249       // End Checks For Reclaiming Locals
250       trace(9999, "mem") << "clearing " << product.original_string << end();
251       zeros.resize(size_of(product));
252       write_memory(product, zeros);
253     }
254   }
255   trace(9999, "mem") << "automatically abandoning " << current_call().default_space << end();
256   abandon(current_call().default_space,
257           inst.products.at(0).type->right,
258           /*refcount*/1 + /*array length*/1 + /*number-of-locals*/Name[r][""]);
259 }
260 
261 //: Reclaiming local variables above requires remembering what name an
262 //: instruction had before any rewrites or transforms.
263 :(before "End instruction Fields")
264 string name_before_rewrite;
265 :(before "End instruction Clear")
266 name_before_rewrite.clear();
267 :(before "End next_instruction(curr)")
268 curr->name_before_rewrite = curr->name;
269 
270 :(code)
271 // is this reagent one of the values returned by the current (return) instruction?
272 // is the corresponding ingredient saved in the caller?
273 bool escaping(const reagent& r) {
274   assert(Current_routine);  // run-time only
275   // nothing escapes when you fall through past end of recipe
276   if (current_step_index() >= SIZE(Current_routine->steps())) return false;
277   for (long long i = 0;  i < SIZE(current_instruction().ingredients);  ++i) {
278     if (r == current_instruction().ingredients.at(i)) {
279       if (caller_uses_product(i))
280         return true;
281     }
282   }
283   return false;
284 }
285 
286 //: since we don't decrement refcounts for escaping values above, make sure we
287 //: don't increment them when the caller saves them either
288 
289 :(after "Write Products of Instruction")
290 Update_refcounts_in_write_memory = should_update_refcounts_in_write_memory();
291 :(before "End Write Products of Instruction")
292 Update_refcounts_in_write_memory = true;
293 :(code)
294 bool should_update_refcounts_in_write_memory() {
295   const instruction& inst = current_instruction();
296   // End should_update_refcounts_in_write_memory Special-cases For Primitives
297   if (inst.operation < MAX_PRIMITIVE_RECIPES) return true;
298   if (!contains_key(Recipe, inst.operation)) return true;
299   const recipe& callee = get(Recipe, inst.operation);
300   if (callee.steps.empty()) return true;
301   return callee.steps.at(0).name_before_rewrite != "local-scope";  // callees that call local-scope are already dealt with before return
302 }
303 
304 bool caller_uses_product(int product_index) {
305   assert(Current_routine);  // run-time only
306   assert(!Current_routine->calls.empty());
307   if (Current_routine->calls.size() == 1) return false;
308   const call& caller = *++Current_routine->calls.begin();
309   const instruction& caller_inst = to_instruction(caller);
310   if (product_index >= SIZE(caller_inst.products)) return false;
311   return !is_dummy(caller_inst.products.at(product_index));
312 }
313 
314 void rewrite_default_space_instruction(instruction& curr) {
315   if (!curr.ingredients.empty())
316     raise << to_original_string(curr) << " can't take any ingredients\n" << end();
317   curr.name = "new";
318   curr.ingredients.push_back(reagent("location:type"));
319   curr.ingredients.push_back(reagent("number-of-locals:literal"));
320   if (!curr.products.empty())
321     raise << "new-default-space can't take any results\n" << end();
322   curr.products.push_back(reagent("default-space:space"));
323 }
324 
325 :(scenario local_scope_frees_up_addresses_inside_containers)
326 container foo [
327   x:num
328   y:&:num
329 ]
330 def main [
331   local-scope
332   x:&:num <- new number:type
333   y:foo <- merge 34, x:&:num
334   # x and y are both cleared when main returns
335 ]
336 +mem: clearing x:&:num
337 +mem: decrementing refcount of 1006: 2 -> 1
338 +mem: clearing y:foo
339 +mem: decrementing refcount of 1006: 1 -> 0
340 +mem: automatically abandoning 1006
341 
342 :(scenario local_scope_returns_addresses_inside_containers)
343 container foo [
344   x:num
345   y:&:num
346 ]
347 def f [
348   local-scope
349   x:&:num <- new number:type
350   *x:&:num <- copy 12
351   y:foo <- merge 34, x:&:num
352   # since y is 'escaping' f, it should not be cleared
353   return y:foo
354 ]
355 def main [
356   1:foo <- f
357   3:num <- get 1:foo, x:offset
358   4:&:num <- get 1:foo, y:offset
359   5:num <- copy *4:&:num
360   1:foo <- put 1:foo, y:offset, 0
361   4:&:num <- copy 0
362 ]
363 +mem: storing 34 in location 1
364 +mem: storing 1006 in location 2
365 +mem: storing 34 in location 3
366 # refcount of 1:foo shouldn't include any stray ones from f
367 +run: {4: ("address" "number")} <- get {1: "foo"}, {y: "offset"}
368 +mem: incrementing refcount of 1006: 1 -> 2
369 # 1:foo wasn't abandoned/cleared
370 +run: {5: "number"} <- copy {4: ("address" "number"), "lookup": ()}
371 +mem: storing 12 in location 5
372 +run: {1: "foo"} <- put {1: "foo"}, {y: "offset"}, {0: "literal"}
373 +mem: decrementing refcount of 1006: 2 -> 1
374 +run: {4: ("address" "number")} <- copy {0: "literal"}
375 +mem: decrementing refcount of 1006: 1 -> 0
376 +mem: automatically abandoning 1006
377 
378 :(scenario local_scope_claims_return_values_when_not_saved)
379 def f [
380   local-scope
381   x:&:num <- new number:type
382   return x:&:num
383 ]
384 def main [
385   f  # doesn't save result
386 ]
387 # x reclaimed
388 +mem: automatically abandoning 1004
389 # f's local scope reclaimed
390 +mem: automatically abandoning 1000
391 
392 //:: all recipes must set default-space one way or another
393 
394 :(before "End Globals")
395 bool Hide_missing_default_space_errors = true;
396 :(before "End Checks")
397 Transform.push_back(check_default_space);  // idempotent
398 :(code)
399 void check_default_space(const recipe_ordinal r) {
400   if (Hide_missing_default_space_errors) return;  // skip previous core tests; this is only for Mu code
401   const recipe& caller = get(Recipe, r);
402   // End check_default_space Special-cases
403   // assume recipes with only numeric addresses know what they're doing (usually tests)
404   if (!contains_non_special_name(r)) return;
405   trace(9991, "transform") << "--- check that recipe " << caller.name << " sets default-space" << end();
406   if (caller.steps.empty()) return;
407   if (caller.steps.at(0).products.empty()
408       || caller.steps.at(0).products.at(0).name != "default-space") {
409     raise << caller.name << " does not seem to start with 'local-scope' or 'default-space'\n" << end();
410   }
411 }
412 :(after "Load Mu Prelude")
413 Hide_missing_default_space_errors = false;
414 :(after "Test Runs")
415 Hide_missing_default_space_errors = true;
416 :(after "Running Main")
417 Hide_missing_default_space_errors = false;
418 
419 :(code)
420 bool contains_non_special_name(const recipe_ordinal r) {
421   for (map<string, int>::iterator p = Name[r].begin();  p != Name[r].end();  ++p) {
422     if (p->first.empty()) continue;
423     if (p->first.find("stash_") == 0) continue;  // generated by rewrite_stashes_to_text (cross-layer)
424     if (!is_special_name(p->first))
425       return true;
426   }
427   return false;
428 }
429 
430 // reagent comparison -- only between reagents in a single recipe
431 bool operator==(const reagent& a, const reagent& b) {
432   if (a.name != b.name) return false;
433   if (property(a, "space") != property(b, "space")) return false;
434   return true;
435 }
436 
437 bool operator<(const reagent& a, const reagent& b) {
438   int aspace = 0, bspace = 0;
439   if (has_property(a, "space")) aspace = to_integer(property(a, "space")->value);
440   if (has_property(b, "space")) bspace = to_integer(property(b, "space")->value);
441   if (aspace != bspace) return aspace < bspace;
442   return a.name < b.name;
443 }