path: root/074deep_copy.cc

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

:(scenario deep_copy_number)
def main [
  local-scope
  x:num <- copy 34
  y:num <- deep-copy x
  10:bool/raw <- equal x, y
]
# non-address primitives are identical
+mem: storing 1 in location 10

:(scenario deep_copy_container_without_address)
container foo [
  x:num
  y:num
]
def main [
  local-scope
  a:foo <- merge 34, 35
  b:foo <- deep-copy a
  10:bool/raw <- equal a, b
]
# containers are identical as long as they don't contain addresses
+mem: storing 1 in location 10

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

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

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

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

:(scenario deep_copy_container_with_address)
container foo [
  x:num
  y:address:num
]
def main [
  local-scope
  y0:address:num <- new number:type
  *y0 <- copy 35
  a:foo <- merge 34, y0
  b:foo <- deep-copy a
  10:bool/raw <- equal a, b
  y1:address:num <- get b, y:offset
  11:bool/raw <- equal y0, y1
  12:num/raw <- copy *y1
]
# containers containing addresses are not identical to their deep copies
+mem: storing 0 in location 10
# the addresses they contain are not identical either
+mem: storing 0 in location 11
+mem: storing 35 in location 12

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

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

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

:(code)
vector<double> deep_copy(const reagent& in, const reagent& tmp) {
  map<int, int> addresses_copied;
  return deep_copy(in, addresses_copied, tmp);
}

vector<double> deep_copy(reagent/*copy*/ in, map<int, int>& addresses_copied, const reagent& tmp) {
  canonize(in);
  vector<double> result;
  if (is_mu_address(in))
    result.push_back(deep_copy_address(in, addresses_copied, tmp));
  else
    deep_copy(in, addresses_copied, tmp, result);
  return result;
}

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

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

int payload_address(reagent/*copy*/ x) {
  x.properties.push_back(pair<string, string_tree*>("lookup", NULL));
  canonize(x);
  return x.value;
}

//: moar tests, just because I can't believe it all works

:(scenario deep_copy_stress_test_1)
container foo1 [
  p:address:num
]
container foo2 [
  p:address:foo1
]
exclusive-container foo3 [
  p:address:foo1
  q:address:foo2
]
def main [
  local-scope
  x:address:num <- new number:type
  *x <- copy 34
  a:address:foo1 <- new foo1:type
  *a <- merge x
  b:address:foo2 <- new foo2:type
  *b <- merge a
  c:foo3 <- merge 1/q, b
  d:foo3 <- deep-copy c
  e:address:foo2, z:bool <- maybe-convert d, q:variant
  f:address:foo1 <- get *e, p:offset
  g:address:num <- get *f, p:offset
  1:num/raw <- copy *g
]
+mem: storing 34 in location 1

:(scenario deep_copy_stress_test_2)
container foo1 [
  p:address:num
]
container foo2 [
  p:address:foo1
]
exclusive-container foo3 [
  p:address:foo1
  q:address:foo2
]
container foo4 [
  p:num
  q:address:foo3
]
def main [
  local-scope
  x:address:num <- new number:type
  *x <- copy 34
  a:address:foo1 <- new foo1:type
  *a <- merge x
  b:address:foo2 <- new foo2:type
  *b <- merge a
  c:address:foo3 <- new foo3:type
  *c <- merge 1/q, b
  d:foo4 <- merge 35, c
  e:foo4 <- deep-copy d
  f:address:foo3 <- get e, q:offset
  g:address:foo2, z:bool <- maybe-convert *f, q:variant
  h:address:foo1 <- get *g, p:offset
  y:address:num <- get *h, p:offset
  1:num/raw <- copy *y
]
+mem: storing 34 in location 1

:(scenario deep_copy_cycles)
container foo [
  p:num
  q:address:foo
]
def main [
  local-scope
  x:address:foo <- new foo:type
  *x <- put *x, p:offset, 34
  *x <- put *x, q:offset, x  # create a cycle
  y:address:foo <- deep-copy x
  1:num/raw <- get *y, p:offset
  y2:address:foo <- get *y, q:offset
  stash y [vs] y2
  2:bool/raw <- equal y, y2  # is it still a cycle?
  3:bool/raw <- equal x, y  # is it the same cycle?
]
+mem: storing 34 in location 1
# deep copy also contains a cycle
+mem: storing 1 in location 2
# but it's a completely different (disjoint) cycle
+mem: storing 0 in location 3