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Diffstat (limited to '060immutable.cc')
| -rw-r--r-- | 060immutable.cc | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/060immutable.cc b/060immutable.cc new file mode 100644 index 00000000..9acd74e3 --- /dev/null +++ b/060immutable.cc @@ -0,0 +1,211 @@ +//: Addresses passed into of a recipe are meant to be immutable unless they're +//: also products. This layer will start enforcing this check. + +:(scenario can_modify_value_ingredients) +% Hide_warnings = true; +recipe main [ + local-scope + p:address:point <- new point:type + foo *p +] +recipe foo p:point [ + local-scope + load-ingredients + x:address:number <- get-address p, x:offset + *x <- copy 34 +] +$warn: 0 + +:(scenario can_modify_ingredients_that_are_also_products) +% Hide_warnings = true; +recipe main [ + local-scope + p:address:point <- new point:type + p <- foo p +] +recipe foo p:address:point -> p:address:point [ + local-scope + load-ingredients + x:address:number <- get-address *p, x:offset + *x <- copy 34 +] +$warn: 0 + +:(scenario cannot_take_address_inside_immutable_ingredients) +% Hide_warnings = true; +recipe main [ + local-scope + p:address:point <- new point:type + foo p +] +recipe foo p:address:point [ + local-scope + load-ingredients + x:address:number <- get-address *p, x:offset + *x <- copy 34 +] ++warn: foo: cannot modify ingredient p after instruction 'x:address:number <- get-address *p, x:offset' because it's not also a product of foo + +:(scenario cannot_call_mutating_recipes_on_immutable_ingredients) +% Hide_warnings = true; +recipe main [ + local-scope + p:address:point <- new point:type + foo p +] +recipe foo p:address:point [ + local-scope + load-ingredients + bar p +] +recipe bar p:address:point -> p:address:point [ + local-scope + load-ingredients + x:address:number <- get-address *p, x:offset + *x <- copy 34 +] ++warn: foo: cannot modify ingredient p at instruction 'bar p' because it's not also a product of foo + +:(scenario can_traverse_immutable_ingredients) +% Hide_warnings = true; +container test-list [ + next:address:test-list +] +recipe main [ + local-scope + p:address:test-list <- new test-list:type + foo p +] +recipe foo p:address:test-list [ + local-scope + load-ingredients + p2:address:test-list <- bar p +] +recipe bar x:address:test-list -> y:address:test-list [ + local-scope + load-ingredients + y <- get *x, next:offset +] +$warn: 0 + +:(before "End Transforms") +Transform.push_back(check_immutable_ingredients); // idempotent + +:(code) +void check_immutable_ingredients(recipe_ordinal r) { + // to ensure a reagent isn't modified, it suffices to show that we never + // call get-address or index-address with it, and that any non-primitive + // recipe calls in the body aren't returning it as a product. + const recipe& caller = get(Recipe, r); + if (!caller.has_header) return; // skip check for old-style recipes calling next-ingredient directly + for (long long int i = 0; i < SIZE(caller.ingredients); ++i) { + const reagent& current_ingredient = caller.ingredients.at(i); + if (!is_mu_address(current_ingredient)) continue; // will be copied + if (is_present_in_products(caller, current_ingredient.name)) continue; // not expected to be immutable + // End Immutable Ingredients Special-cases + for (long long int i = 0; i < SIZE(caller.steps); ++i) { + check_immutable_ingredient_in_instruction(caller.steps.at(i), current_ingredient.name, caller); + } + } +} + +void check_immutable_ingredient_in_instruction(const instruction& inst, const string& current_ingredient_name, const recipe& caller) { + long long int current_ingredient_index = find_ingredient_index(inst, current_ingredient_name); + if (current_ingredient_index == -1) return; // ingredient not found in call + reagent current_ingredient = inst.ingredients.at(current_ingredient_index); + canonize_type(current_ingredient); + if (!contains_key(Recipe, inst.operation)) { + // primitive recipe + if (inst.operation == GET_ADDRESS || inst.operation == INDEX_ADDRESS) + raise << maybe(caller.name) << "cannot modify ingredient " << current_ingredient_name << " after instruction '" << inst.to_string() << "' because it's not also a product of " << caller.name << '\n' << end(); + } + else { + // defined recipe + if (!is_mu_address(current_ingredient)) return; // making a copy is ok + if (is_modified_in_recipe(inst.operation, current_ingredient_index, caller)) + raise << maybe(caller.name) << "cannot modify ingredient " << current_ingredient_name << " at instruction '" << inst.to_string() << "' because it's not also a product of " << caller.name << '\n' << end(); + } +} + +bool is_modified_in_recipe(recipe_ordinal r, long long int ingredient_index, const recipe& caller) { + const recipe& callee = get(Recipe, r); + if (!callee.has_header) { + raise << maybe(caller.name) << "can't check mutability of ingredients in " << callee.name << " because it uses 'next-ingredient' directly, rather than a recipe header.\n" << end(); + return true; + } + return is_present_in_products(callee, callee.ingredients.at(ingredient_index).name); +} + +bool is_present_in_products(const recipe& callee, const string& ingredient_name) { + for (long long int i = 0; i < SIZE(callee.products); ++i) { + if (callee.products.at(i).name == ingredient_name) + return true; + } + return false; +} + +bool is_present_in_ingredients(const recipe& callee, const string& ingredient_name) { + for (long long int i = 0; i < SIZE(callee.ingredients); ++i) { + if (callee.ingredients.at(i).name == ingredient_name) + return true; + } + return false; +} + +long long int find_ingredient_index(const instruction& inst, const string& ingredient_name) { + for (long long int i = 0; i < SIZE(inst.ingredients); ++i) { + if (inst.ingredients.at(i).name == ingredient_name) + return i; + } + return -1; +} + +//: Sometimes you want to pass in two addresses, one pointing inside the +//: other. For example, you want to delete a node from a linked list. You +//: can't pass both pointers back out, because if a caller tries to make both +//: identical then you can't tell which value will be written on the way out. +//: +//: Experimental solution: just tell mu that one points inside the other. +//: This way we can return just one pointer as high up as necessary to capture +//: all modifications performed by a recipe. +//: +//: We'll see if we end up wanting to abuse /contained-in for other reasons. + +:(scenarios transform) +:(scenario can_modify_contained_in_addresses) +#% Hide_warnings = true; +container test-list [ + next:address:test-list +] +recipe main [ + local-scope + p:address:test-list <- new test-list:type + foo p +] +recipe foo p:address:test-list -> p:address:test-list [ + local-scope + load-ingredients + p2:address:test-list <- test-next p + p <- test-remove p2, p +] +recipe test-next x:address:test-list -> y:address:test-list [ + local-scope + load-ingredients + y <- get *x, next:offset +] +recipe test-remove x:address:test-list/contained-in:from, from:address:test-list -> from:address:test-list [ + local-scope + load-ingredients + x2:address:address:test-list <- get-address *x, next:offset # pretend modification +] +$warn: 0 + +:(before "End Immutable Ingredients Special-cases") +if (has_property(current_ingredient, "contained-in")) { + const string_tree* tmp = property(current_ingredient, "contained-in"); + if (tmp->left || tmp->right + || !is_present_in_ingredients(caller, tmp->value) + || !is_present_in_products(caller, tmp->value)) + raise_error << maybe(caller.name) << "contained-in can only point to another ingredient+product, but got " << debug_string(property(current_ingredient, "contained-in")) << '\n' << end(); + continue; +} |