2864 - replace all address:shared with just address

Now that we no longer have non-shared addresses, we can just always
track refcounts for all addresses.

Phew!

1 files changed, 0 insertions, 686 deletions

diff --git a/034new.cc b/034new.cc
deleted file mode 100644
index ec30fee1..00000000
--- a/034new.cc
+++ /dev/null
@@ -1,686 +0,0 @@
-//: Creating space for new variables at runtime.
-
-//: Mu has two primitives for managing allocations:
-//: - 'allocate' reserves a specified amount of space
-//: - 'abandon' returns allocated space to be reused by future calls to 'allocate'
-//:
-//: In practice it's useful to let programs copy addresses anywhere they want,
-//: but a prime source of (particularly security) bugs is accessing memory
-//: after it's been abandoned. To avoid this, mu programs use a safer
-//: primitive called 'new', which adds two features:
-//:
-//: - it takes a type rather than a size, to save you the trouble of
-//: calculating sizes of different variables.
-//: - it allocates an extra location where it tracks so-called 'reference
-//: counts' or refcounts: the number of address variables in your program that
-//: point to this allocation. The initial refcount of an allocation starts out
-//: at 1 (the product of the 'new' instruction). When other variables are
-//: copied from it the refcount is incremented. When a variable stops pointing
-//: at it the refcount is decremented. When the refcount goes to 0 the
-//: allocation is automatically abandoned.
-//:
-//: Mu programs guarantee you'll have no memory corruption bugs as long as you
-//: use 'new' and never use 'allocate' or 'abandon'. However, they don't help
-//: you at all to remember to abandon memory after you're done with it. To
-//: minimize memory use, be sure to reset allocated addresses to 0 when you're
-//: done with them.
-
-//: interlude {
-//: To help you distinguish addresses that point at allocations, 'new' returns
-//: type address:shared:___. Think of 'shared' as a generic container that
-//: contains one extra field: the refcount. However, lookup operations will
-//: transparently drop the 'shared' and access to the refcount. Copying
-//: between shared and non-shared addresses is forbidden.
-:(before "End Mu Types Initialization")
-type_ordinal shared = put(Type_ordinal, "shared", Next_type_ordinal++);
-get_or_insert(Type, shared).name = "shared";
-:(before "End Drop Address In lookup_memory(x)")
-if (x.type->name == "shared" && x.value != 0) {
-  trace(9999, "mem") << "skipping refcount at " << x.value << end();
-  x.set_value(x.value+1);  // skip refcount
-  drop_from_type(x, "shared");
-}
-:(before "End Drop Address In canonize_type(r)")
-if (r.type->name == "shared") {
-  drop_from_type(r, "shared");
-}
-
-:(code)
-void test_lookup_shared_address() {
-  reagent x("*x:address:shared:number");
-  x.set_value(34);  // unsafe
-  put(Memory, 34, 1000);
-  lookup_memory(x);
-  CHECK_TRACE_CONTENTS("mem: skipping refcount at 1000");
-  CHECK_EQ(x.value, 1001);
-}
-
-void test_lookup_shared_address_skip_zero() {
-  reagent x("*x:address:shared:number");
-  x.set_value(34);  // unsafe
-  put(Memory, 34, 0);
-  lookup_memory(x);
-  CHECK_TRACE_DOESNT_CONTAIN("mem: skipping refcount at 0");
-  CHECK_EQ(x.value, 0);
-}
-
-//: } end interlude
-
-:(scenarios run)
-:(scenario new)
-# call new two times with identical arguments; you should get back different results
-def main [
-  1:address:shared:number/raw <- new number:type
-  2:address:shared:number/raw <- new number:type
-  3:boolean/raw <- equal 1:address:shared:number/raw, 2:address:shared:number/raw
-]
-+mem: storing 0 in location 3
-
-:(before "End Globals")
-const int Reserved_for_tests = 1000;
-int Memory_allocated_until = Reserved_for_tests;
-int Initial_memory_per_routine = 100000;
-:(before "End Setup")
-Memory_allocated_until = Reserved_for_tests;
-Initial_memory_per_routine = 100000;
-:(before "End routine Fields")
-int alloc, alloc_max;
-:(before "End routine Constructor")
-alloc = Memory_allocated_until;
-Memory_allocated_until += Initial_memory_per_routine;
-alloc_max = Memory_allocated_until;
-trace(9999, "new") << "routine allocated memory from " << alloc << " to " << alloc_max << end();
-
-//:: 'new' takes a weird 'type' as its first ingredient; don't error on it
-:(before "End Mu Types Initialization")
-put(Type_ordinal, "type", 0);
-
-//:: typecheck 'new' instructions
-:(before "End Primitive Recipe Declarations")
-NEW,
-:(before "End Primitive Recipe Numbers")
-put(Recipe_ordinal, "new", NEW);
-:(before "End Primitive Recipe Checks")
-case NEW: {
-  const recipe& caller = get(Recipe, r);
-  if (inst.ingredients.empty() || SIZE(inst.ingredients) > 2) {
-    raise << maybe(caller.name) << "'new' requires one or two ingredients, but got " << to_original_string(inst) << '\n' << end();
-    break;
-  }
-  // End NEW Check Special-cases
-  reagent type = inst.ingredients.at(0);
-  if (!is_mu_type_literal(type)) {
-    raise << maybe(caller.name) << "first ingredient of 'new' should be a type, but got " << type.original_string << '\n' << end();
-    break;
-  }
-  if (inst.products.empty()) {
-    raise << maybe(caller.name) << "result of 'new' should never be ignored\n" << end();
-    break;
-  }
-  if (!product_of_new_is_valid(inst)) {
-    raise << maybe(caller.name) << "product of 'new' has incorrect type: " << to_original_string(inst) << '\n' << end();
-    break;
-  }
-  break;
-}
-:(code)
-bool product_of_new_is_valid(const instruction& inst) {
-  reagent product = inst.products.at(0);
-  canonize_type(product);
-  if (!product.type || product.type->value != get(Type_ordinal, "address")) return false;
-  drop_from_type(product, "address");
-  if (!product.type || product.type->value != get(Type_ordinal, "shared")) return false;
-  drop_from_type(product, "shared");
-  if (SIZE(inst.ingredients) > 1) {
-    // array allocation
-    if (!product.type || product.type->value != get(Type_ordinal, "array")) return false;
-    drop_from_type(product, "array");
-  }
-  reagent expected_product("x:"+inst.ingredients.at(0).name);
-  // End Post-processing(expected_product) When Checking 'new'
-  return types_strictly_match(product, expected_product);
-}
-
-//:: translate 'new' to 'allocate' instructions that take a size instead of a type
-:(after "Transform.push_back(check_instruction)")  // check_instruction will guard against direct 'allocate' instructions below
-Transform.push_back(transform_new_to_allocate);  // idempotent
-
-:(code)
-void transform_new_to_allocate(const recipe_ordinal r) {
-  trace(9991, "transform") << "--- convert 'new' to 'allocate' for recipe " << get(Recipe, r).name << end();
-  for (int i = 0; i < SIZE(get(Recipe, r).steps); ++i) {
-    instruction& inst = get(Recipe, r).steps.at(i);
-    // Convert 'new' To 'allocate'
-    if (inst.name == "new") {
-      inst.operation = ALLOCATE;
-      string_tree* type_name = new string_tree(inst.ingredients.at(0).name);
-      // End Post-processing(type_name) When Converting 'new'
-      type_tree* type = new_type_tree(type_name);
-      inst.ingredients.at(0).set_value(size_of(type));
-      trace(9992, "new") << "size of " << to_string(type_name) << " is " << inst.ingredients.at(0).value << end();
-      delete type;
-      delete type_name;
-    }
-  }
-}
-
-//:: implement 'allocate' based on size
-
-:(before "End Primitive Recipe Declarations")
-ALLOCATE,
-:(before "End Primitive Recipe Numbers")
-put(Recipe_ordinal, "allocate", ALLOCATE);
-:(before "End Primitive Recipe Implementations")
-case ALLOCATE: {
-  // compute the space we need
-  int size = ingredients.at(0).at(0);
-  if (SIZE(ingredients) > 1) {
-    // array
-    trace(9999, "mem") << "array size is " << ingredients.at(1).at(0) << end();
-    size = /*space for length*/1 + size*ingredients.at(1).at(0);
-  }
-  // include space for refcount
-  size++;
-  trace(9999, "mem") << "allocating size " << size << end();
-//?   Total_alloc += size;
-//?   Num_alloc++;
-  // compute the region of memory to return
-  // really crappy at the moment
-  ensure_space(size);
-  const int result = Current_routine->alloc;
-  trace(9999, "mem") << "new alloc: " << result << end();
-  // save result
-  products.resize(1);
-  products.at(0).push_back(result);
-  // initialize allocated space
-  for (int address = result; address < result+size; ++address)
-    put(Memory, address, 0);
-  // initialize array length
-  if (SIZE(current_instruction().ingredients) > 1) {
-    trace(9999, "mem") << "storing " << ingredients.at(1).at(0) << " in location " << result+/*skip refcount*/1 << end();
-    put(Memory, result+/*skip refcount*/1, ingredients.at(1).at(0));
-  }
-  // bump
-  Current_routine->alloc += size;
-  // no support for reclaiming memory
-  assert(Current_routine->alloc <= Current_routine->alloc_max);
-  break;
-}
-
-//:: ensure we never call 'allocate' directly; its types are not checked
-:(before "End Primitive Recipe Checks")
-case ALLOCATE: {
-  raise << "never call 'allocate' directly'; always use 'new'\n" << end();
-  break;
-}
-
-//:: ensure we never call 'new' without translating it (unless we add special-cases later)
-:(before "End Primitive Recipe Implementations")
-case NEW: {
-  raise << "no implementation for 'new'; why wasn't it translated to 'allocate'? Please save a copy of your program and send it to Kartik.\n" << end();
-  break;
-}
-
-//? :(before "End Globals")
-//? int Total_alloc = 0;
-//? int Num_alloc = 0;
-//? int Total_free = 0;
-//? int Num_free = 0;
-//? :(before "End Setup")
-//? Total_alloc = Num_alloc = Total_free = Num_free = 0;
-//? :(before "End Teardown")
-//? cerr << Total_alloc << "/" << Num_alloc
-//?      << " vs " << Total_free << "/" << Num_free << '\n';
-//? cerr << SIZE(Memory) << '\n';
-
-:(code)
-void ensure_space(int size) {
-  if (size > Initial_memory_per_routine) {
-    tb_shutdown();
-    cerr << "can't allocate " << size << " locations, that's too much compared to " << Initial_memory_per_routine << ".\n";
-    exit(0);
-  }
-  if (Current_routine->alloc + size > Current_routine->alloc_max) {
-    // waste the remaining space and create a new chunk
-    Current_routine->alloc = Memory_allocated_until;
-    Memory_allocated_until += Initial_memory_per_routine;
-    Current_routine->alloc_max = Memory_allocated_until;
-    trace(9999, "new") << "routine allocated memory from " << Current_routine->alloc << " to " << Current_routine->alloc_max << end();
-  }
-}
-
-:(scenario new_initializes)
-% Memory_allocated_until = 10;
-% put(Memory, Memory_allocated_until, 1);
-def main [
-  1:address:shared:number <- new number:type
-  2:number <- copy *1:address:shared:number
-]
-+mem: storing 0 in location 2
-
-:(scenario new_error)
-% Hide_errors = true;
-def main [
-  1:address:number/raw <- new number:type
-]
-+error: main: product of 'new' has incorrect type: 1:address:number/raw <- new number:type
-
-:(scenario new_array)
-def main [
-  1:address:shared:array:number/raw <- new number:type, 5
-  2:address:shared:number/raw <- new number:type
-  3:number/raw <- subtract 2:address:shared:number/raw, 1:address:shared:array:number/raw
-]
-+run: {1: ("address" "shared" "array" "number"), "raw": ()} <- new {number: "type"}, {5: "literal"}
-+mem: array size is 5
-# don't forget the extra location for array size, and the second extra location for the refcount
-+mem: storing 7 in location 3
-
-:(scenario new_empty_array)
-def main [
-  1:address:shared:array:number/raw <- new number:type, 0
-  2:address:shared:number/raw <- new number:type
-  3:number/raw <- subtract 2:address:shared:number/raw, 1:address:shared:array:number/raw
-]
-+run: {1: ("address" "shared" "array" "number"), "raw": ()} <- new {number: "type"}, {0: "literal"}
-+mem: array size is 0
-# one location for array size, and one for the refcount
-+mem: storing 2 in location 3
-
-//: If a routine runs out of its initial allocation, it should allocate more.
-:(scenario new_overflow)
-% Initial_memory_per_routine = 3;  // barely enough room for point allocation below
-def main [
-  1:address:shared:number/raw <- new number:type
-  2:address:shared:point/raw <- new point:type  # not enough room in initial page
-]
-+new: routine allocated memory from 1000 to 1003
-+new: routine allocated memory from 1003 to 1006
-
-//:: A way to return memory, and to reuse reclaimed memory.
-//: todo: custodians, etc. Following malloc/free is a temporary hack.
-
-:(scenario new_reclaim)
-def main [
-  1:address:shared:number <- new number:type
-  2:address:shared:number <- copy 1:address:shared:number  # because 1 will get reset during abandon below
-  abandon 1:address:shared:number  # unsafe
-  3:address:shared:number <- new number:type  # must be same size as abandoned memory to reuse
-  4:boolean <- equal 2:address:shared:number, 3:address:shared:number
-]
-# both allocations should have returned the same address
-+mem: storing 1 in location 4
-
-:(before "End routine Fields")
-map<int, int> free_list;
-
-:(before "End Primitive Recipe Declarations")
-ABANDON,
-:(before "End Primitive Recipe Numbers")
-put(Recipe_ordinal, "abandon", ABANDON);
-:(before "End Primitive Recipe Checks")
-case ABANDON: {
-  if (SIZE(inst.ingredients) != 1) {
-    raise << maybe(get(Recipe, r).name) << "'abandon' requires one ingredient, but got '" << to_original_string(inst) << "'\n" << end();
-    break;
-  }
-  reagent types = inst.ingredients.at(0);
-  canonize_type(types);
-  if (!types.type || types.type->value != get(Type_ordinal, "address") || types.type->right->value != get(Type_ordinal, "shared")) {
-    raise << maybe(get(Recipe, r).name) << "first ingredient of 'abandon' should be an address:shared:___, but got " << inst.ingredients.at(0).original_string << '\n' << end();
-    break;
-  }
-  break;
-}
-:(before "End Primitive Recipe Implementations")
-case ABANDON: {
-  int address = ingredients.at(0).at(0);
-  trace(9999, "abandon") << "address to abandon is " << address << end();
-  reagent types = current_instruction().ingredients.at(0);
-  trace(9999, "abandon") << "value of ingredient is " << types.value << end();
-  canonize(types);
-  // lookup_memory without drop_one_lookup {
-  trace(9999, "abandon") << "value of ingredient after canonization is " << types.value << end();
-  int address_location = types.value;
-  types.set_value(get_or_insert(Memory, types.value)+/*skip refcount*/1);
-  drop_from_type(types, "address");
-  drop_from_type(types, "shared");
-  // }
-  abandon(address, size_of(types)+/*refcount*/1);
-  // clear the address
-  trace(9999, "mem") << "resetting location " << address_location << end();
-  put(Memory, address_location, 0);
-  break;
-}
-
-:(code)
-void abandon(int address, int size) {
-  trace(9999, "abandon") << "saving in free-list of size " << size << end();
-//?   Total_free += size;
-//?   Num_free++;
-//?   cerr << "abandon: " << size << '\n';
-  // clear memory
-  for (int curr = address; curr < address+size; ++curr)
-    put(Memory, curr, 0);
-  // append existing free list to address
-  put(Memory, address, get_or_insert(Current_routine->free_list, size));
-  put(Current_routine->free_list, size, address);
-}
-
-:(before "ensure_space(size)" following "case ALLOCATE")
-if (get_or_insert(Current_routine->free_list, size)) {
-  trace(9999, "abandon") << "picking up space from free-list of size " << size << end();
-  int result = get_or_insert(Current_routine->free_list, size);
-  trace(9999, "mem") << "new alloc from free list: " << result << end();
-  put(Current_routine->free_list, size, get_or_insert(Memory, result));
-  for (int curr = result+1; curr < result+size; ++curr) {
-    if (get_or_insert(Memory, curr) != 0) {
-      raise << maybe(current_recipe_name()) << "memory in free list was not zeroed out: " << curr << '/' << result << "; somebody wrote to us after free!!!\n" << end();
-      break;  // always fatal
-    }
-  }
-  if (SIZE(current_instruction().ingredients) > 1)
-    put(Memory, result+/*skip refcount*/1, ingredients.at(1).at(0));
-  else
-    put(Memory, result, 0);
-  products.resize(1);
-  products.at(0).push_back(result);
-  break;
-}
-
-:(scenario new_differing_size_no_reclaim)
-def main [
-  1:address:shared:number <- new number:type
-  2:address:shared:number <- copy 1:address:shared:number
-  abandon 1:address:shared:number
-  3:address:shared:array:number <- new number:type, 2  # different size
-  4:boolean <- equal 2:address:shared:number, 3:address:shared:array:number
-]
-# no reuse
-+mem: storing 0 in location 4
-
-:(scenario new_reclaim_array)
-def main [
-  1:address:shared:array:number <- new number:type, 2
-  2:address:shared:array:number <- copy 1:address:shared:array:number
-  abandon 1:address:shared:array:number  # unsafe
-  3:address:shared:array:number <- new number:type, 2
-  4:boolean <- equal 2:address:shared:array:number, 3:address:shared:array:number
-]
-# reuse
-+mem: storing 1 in location 4
-
-:(scenario reset_on_abandon)
-def main [
-  1:address:shared:number <- new number:type
-  abandon 1:address:shared:number
-]
-# reuse
-+run: abandon {1: ("address" "shared" "number")}
-+mem: resetting location 1
-
-//:: Manage refcounts when copying addresses.
-
-:(scenario refcounts)
-def main [
-  1:address:shared:number <- copy 1000/unsafe
-  2:address:shared:number <- copy 1:address:shared:number
-  1:address:shared:number <- copy 0
-  2:address:shared:number <- copy 0
-]
-+run: {1: ("address" "shared" "number")} <- copy {1000: "literal", "unsafe": ()}
-+mem: incrementing refcount of 1000: 0 -> 1
-+run: {2: ("address" "shared" "number")} <- copy {1: ("address" "shared" "number")}
-+mem: incrementing refcount of 1000: 1 -> 2
-+run: {1: ("address" "shared" "number")} <- copy {0: "literal"}
-+mem: decrementing refcount of 1000: 2 -> 1
-+run: {2: ("address" "shared" "number")} <- copy {0: "literal"}
-+mem: decrementing refcount of 1000: 1 -> 0
-# the /unsafe corrupts memory but fortunately we won't be running any more 'new' in this scenario
-+mem: automatically abandoning 1000
-
-:(before "End write_memory(reagent x) Special-cases")
-if (x.type->value == get(Type_ordinal, "address")
-    && x.type->right
-    && x.type->right->value == get(Type_ordinal, "shared")) {
-  // compute old address of x, as well as new address we want to write in
-  int old_address = get_or_insert(Memory, x.value);
-  assert(scalar(data));
-  int new_address = data.at(0);
-  // decrement refcount of old address
-  if (old_address) {
-    int old_refcount = get_or_insert(Memory, old_address);
-    trace(9999, "mem") << "decrementing refcount of " << old_address << ": " << old_refcount << " -> " << (old_refcount-1) << end();
-    put(Memory, old_address, old_refcount-1);
-  }
-  // perform the write
-  trace(9999, "mem") << "storing " << no_scientific(data.at(0)) << " in location " << x.value << end();
-  put(Memory, x.value, new_address);
-  // increment refcount of new address
-  if (new_address) {
-    int new_refcount = get_or_insert(Memory, new_address);
-    assert(new_refcount >= 0);  // == 0 only when new_address == old_address
-    trace(9999, "mem") << "incrementing refcount of " << new_address << ": " << new_refcount << " -> " << (new_refcount+1) << end();
-    put(Memory, new_address, new_refcount+1);
-  }
-  // abandon old address if necessary
-  // do this after all refcount updates are done just in case old and new are identical
-  assert(old_address >= 0);
-  if (old_address == 0) return;
-  assert(get_or_insert(Memory, old_address) >= 0);
-  if (get_or_insert(Memory, old_address) > 0) return;
-  // lookup_memory without drop_one_lookup {
-  trace(9999, "mem") << "automatically abandoning " << old_address << end();
-  trace(9999, "mem") << "computing size to abandon at " << x.value << end();
-  x.set_value(old_address+/*skip refcount*/1);
-  drop_from_type(x, "address");
-  drop_from_type(x, "shared");
-  // }
-  abandon(old_address, size_of(x)+/*refcount*/1);
-  return;
-}
-
-:(scenario refcounts_2)
-def main [
-  1:address:shared:number <- new number:type
-  # over-writing one allocation with another
-  1:address:shared:number <- new number:type
-  1:address:shared:number <- copy 0
-]
-+run: {1: ("address" "shared" "number")} <- new {number: "type"}
-+mem: incrementing refcount of 1000: 0 -> 1
-+run: {1: ("address" "shared" "number")} <- new {number: "type"}
-+mem: automatically abandoning 1000
-
-:(scenario refcounts_3)
-def main [
-  1:address:shared:number <- new number:type
-  # passing in addresses to recipes increments refcount
-  foo 1:address:shared:number
-  1:address:shared:number <- copy 0
-]
-def foo [
-  2:address:shared:number <- next-ingredient
-  # return does NOT yet decrement refcount; memory must be explicitly managed
-  2:address:shared:number <- copy 0
-]
-+run: {1: ("address" "shared" "number")} <- new {number: "type"}
-+mem: incrementing refcount of 1000: 0 -> 1
-+run: {2: ("address" "shared" "number")} <- next-ingredient
-+mem: incrementing refcount of 1000: 1 -> 2
-+run: {2: ("address" "shared" "number")} <- copy {0: "literal"}
-+mem: decrementing refcount of 1000: 2 -> 1
-+run: {1: ("address" "shared" "number")} <- copy {0: "literal"}
-+mem: decrementing refcount of 1000: 1 -> 0
-+mem: automatically abandoning 1000
-
-:(scenario refcounts_4)
-def main [
-  1:address:shared:number <- new number:type
-  # idempotent copies leave refcount unchanged
-  1:address:shared:number <- copy 1:address:shared:number
-]
-+run: {1: ("address" "shared" "number")} <- new {number: "type"}
-+mem: incrementing refcount of 1000: 0 -> 1
-+run: {1: ("address" "shared" "number")} <- copy {1: ("address" "shared" "number")}
-+mem: decrementing refcount of 1000: 1 -> 0
-+mem: incrementing refcount of 1000: 0 -> 1
-
-:(scenario refcounts_5)
-def main [
-  1:address:shared:number <- new number:type
-  # passing in addresses to recipes increments refcount
-  foo 1:address:shared:number
-  # return does NOT yet decrement refcount; memory must be explicitly managed
-  1:address:shared:number <- new number:type
-]
-def foo [
-  2:address:shared:number <- next-ingredient
-]
-+run: {1: ("address" "shared" "number")} <- new {number: "type"}
-+mem: incrementing refcount of 1000: 0 -> 1
-+run: {2: ("address" "shared" "number")} <- next-ingredient
-+mem: incrementing refcount of 1000: 1 -> 2
-+run: {1: ("address" "shared" "number")} <- new {number: "type"}
-+mem: decrementing refcount of 1000: 2 -> 1
-
-:(scenario refcounts_array)
-def main [
-  1:number <- copy 30
-  # allocate an array
-  10:address:shared:array:number <- new number:type, 20
-  11:number <- copy 10:address:shared:array:number
-  # allocate another array in its place, implicitly freeing the previous allocation
-  10:address:shared:array:number <- new number:type, 25
-]
-+run: {10: ("address" "shared" "array" "number")} <- new {number: "type"}, {20: "literal"}
-# abandoned array is of old size (20, not 25)
-+abandon: saving in free-list of size 22
-
-//:: Extend 'new' to handle a unicode string literal argument.
-
-:(scenario new_string)
-def main [
-  1:address:shared:array:character <- new [abc def]
-  2:character <- index *1:address:shared:array:character, 5
-]
-# number code for 'e'
-+mem: storing 101 in location 2
-
-:(scenario new_string_handles_unicode)
-def main [
-  1:address:shared:array:character <- new [a«c]
-  2:number <- length *1:address:shared:array:character
-  3:character <- index *1:address:shared:array:character, 1
-]
-+mem: storing 3 in location 2
-# unicode for '«'
-+mem: storing 171 in location 3
-
-:(before "End NEW Check Special-cases")
-if (is_literal_string(inst.ingredients.at(0))) break;
-:(before "Convert 'new' To 'allocate'")
-if (inst.name == "new" && is_literal_string(inst.ingredients.at(0))) continue;
-:(after "case NEW" following "Primitive Recipe Implementations")
-  if (is_literal_string(current_instruction().ingredients.at(0))) {
-    products.resize(1);
-    products.at(0).push_back(new_mu_string(current_instruction().ingredients.at(0).name));
-    trace(9999, "mem") << "new string alloc: " << products.at(0).at(0) << end();
-    break;
-  }
-
-:(code)
-int new_mu_string(const string& contents) {
-  // allocate an array just large enough for it
-  int string_length = unicode_length(contents);
-//?   Total_alloc += string_length+1;
-//?   Num_alloc++;
-  ensure_space(string_length+1);  // don't forget the extra location for array size
-  // initialize string
-  int result = Current_routine->alloc;
-  // initialize refcount
-  put(Memory, Current_routine->alloc++, 0);
-  // store length
-  put(Memory, Current_routine->alloc++, string_length);
-  int curr = 0;
-  const char* raw_contents = contents.c_str();
-  for (int i = 0; i < string_length; ++i) {
-    uint32_t curr_character;
-    assert(curr < SIZE(contents));
-    tb_utf8_char_to_unicode(&curr_character, &raw_contents[curr]);
-    put(Memory, Current_routine->alloc, curr_character);
-    curr += tb_utf8_char_length(raw_contents[curr]);
-    ++Current_routine->alloc;
-  }
-  // mu strings are not null-terminated in memory
-  return result;
-}
-
-//: stash recognizes strings
-
-:(scenario stash_string)
-def main [
-  1:address:shared:array:character <- new [abc]
-  stash [foo:], 1:address:shared:array:character
-]
-+app: foo: abc
-
-:(before "End print Special-cases(reagent r, data)")
-if (is_mu_string(r)) {
-  assert(scalar(data));
-  return read_mu_string(data.at(0))+' ';
-}
-
-:(scenario unicode_string)
-def main [
-  1:address:shared:array:character <- new [♠]
-  stash [foo:], 1:address:shared:array:character
-]
-+app: foo: ♠
-
-:(scenario stash_space_after_string)
-def main [
-  1:address:shared:array:character <- new [abc]
-  stash 1:address:shared:array:character, [foo]
-]
-+app: abc foo
-
-//: Allocate more to routine when initializing a literal string
-:(scenario new_string_overflow)
-% Initial_memory_per_routine = 2;
-def main [
-  1:address:shared:number/raw <- new number:type
-  2:address:shared:array:character/raw <- new [a]  # not enough room in initial page, if you take the array size into account
-]
-+new: routine allocated memory from 1000 to 1002
-+new: routine allocated memory from 1002 to 1004
-
-//: helpers
-:(code)
-int unicode_length(const string& s) {
-  const char* in = s.c_str();
-  int result = 0;
-  int curr = 0;
-  while (curr < SIZE(s)) {  // carefully bounds-check on the string
-    // before accessing its raw pointer
-    ++result;
-    curr += tb_utf8_char_length(in[curr]);
-  }
-  return result;
-}
-
-string read_mu_string(int address) {
-  if (address == 0) return "";
-  address++;  // skip refcount
-  int size = get_or_insert(Memory, address);
-  if (size == 0) return "";
-  ostringstream tmp;
-  for (int curr = address+1; curr <= address+size; ++curr) {
-    tmp << to_unicode(static_cast<uint32_t>(get_or_insert(Memory, curr)));
-  }
-  return tmp.str();
-}
-
-bool is_mu_type_literal(reagent r) {
-  return is_literal(r) && r.type && r.type->name == "type";
-}