CSY/reowolf Changeset - 0e1a76667937 · Centrum Wiskunde & Informatica (CWI)

Changeset - 0e1a76667937

Parent rev.

Child rev.

[Not reviewed]

0 7 4

MH - 3 years ago 2022-01-05 12:11:03
contact@maxhenger.nl

Started work on speculationless runtime

11 files changed with 1188 insertions and 250 deletions:

Cargo.toml

src/protocol/eval/executor.rs

src/protocol/eval/mod.rs

src/runtime2/communication.rs

src/runtime2/component.rs

216

src/runtime2/mod.rs

src/runtime2/runtime.rs

103

243

src/runtime2/scheduler.rs

src/runtime2/store/component.rs

559

src/runtime2/store/mod.rs

src/runtime2/store/unfair_se_lock.rs

194

0 comments (0 inline, 0 general)

Cargo.toml

➞

Show inline comments

 [package]
 name = "reowolf_rs"
 version = "1.2.0"
 authors = [
 	"Max Henger <henger@cwi.nl>",
 	"Christopher Esterhuyse <esterhuy@cwi.nl>",
 	"Hans-Dieter Hiep <hdh@cwi.nl>"
+]
 edition = "2018"
 [dependencies]
 # convenience macros
 maplit = "1.0.2"
 derive_more = "0.99.2"
 # runtime
 bincode = "1.3.1"
 serde = { version = "1.0.114", features = ["derive"] }
 getrandom = "0.1.14" # tiny crate. used to guess controller-id
 # network
 mio = { version = "0.7.0", package = "mio", features = ["udp", "tcp", "os-poll"] }
 socket2 = { version = "0.3.12", optional = true }
 # protocol
 backtrace = "0.3"
 lazy_static = "1.4.0"
 # ffi
 # socket ffi
 libc = { version = "^0.2", optional = true }
 os_socketaddr = { version = "0.1.0", optional = true }
 [dev-dependencies]
 # test-generator = "0.3.0"
 crossbeam-utils = "0.7.2"
 lazy_static = "1.4.0"
 rand = "0.8.4"
 rand_pcg = "0.3.1"
 [lib]
 crate-type = [
 	"rlib", # for use as a Rust dependency.
+]
@@ \ No newline at end of file @@

src/protocol/eval/executor.rs

➞

Show inline comments

 use std::collections::VecDeque;
 use super::value::*;
 use super::store::*;
 use super::error::*;
 use crate::protocol::*;
 use crate::protocol::ast::*;
 use crate::protocol::type_table::*;
 macro_rules! debug_enabled { () => { false }; }
 macro_rules! debug_log {
     ($format:literal) => {
         enabled_debug_print!(false, "exec", $format);
     };
     ($format:literal, $($args:expr),*) => {
         enabled_debug_print!(false, "exec", $format, $($args),*);
     };
+}
 #[derive(Debug, Clone)]
 pub(crate) enum ExprInstruction {
     EvalExpr(ExpressionId),
     PushValToFront,
+}
 #[derive(Debug, Clone)]
 pub(crate) struct Frame {
     pub(crate) definition: DefinitionId,
     pub(crate) monomorph_idx: i32,
     pub(crate) position: StatementId,
     pub(crate) expr_stack: VecDeque<ExprInstruction>, // hack for expression evaluation, evaluated by popping from back
     pub(crate) expr_values: VecDeque<Value>, // hack for expression results, evaluated by popping from front/back
     pub(crate) max_stack_size: u32,
+}
 impl Frame {
     /// Creates a new execution frame. Does not modify the stack in any way.
     pub fn new(heap: &Heap, definition_id: DefinitionId, monomorph_idx: i32) -> Self {
         let definition = &heap[definition_id];
         let first_statement = match definition {
             Definition::Component(definition) => definition.body,
             Definition::Function(definition) => definition.body,
             _ => unreachable!("initializing frame with {:?} instead of a function/component", definition),
         };
         // Another not-so-pretty thing that has to be replaced somewhere in the
         // future...
         fn determine_max_stack_size(heap: &Heap, block_id: BlockStatementId, max_size: &mut u32) {
             let block_stmt = &heap[block_id];
             debug_assert!(block_stmt.next_unique_id_in_scope >= 0);
             // Check current block
             let cur_size = block_stmt.next_unique_id_in_scope as u32;
             if cur_size > *max_size { *max_size = cur_size; }
             // And child blocks
             for child_scope in &block_stmt.scope_node.nested {
                 determine_max_stack_size(heap, child_scope.to_block(), max_size);
+            }
+        }
         let mut max_stack_size = 0;
         determine_max_stack_size(heap, first_statement, &mut max_stack_size);
         Frame{
             definition: definition_id,
             monomorph_idx,
             position: first_statement.upcast(),
             expr_stack: VecDeque::with_capacity(128),
             expr_values: VecDeque::with_capacity(128),
             max_stack_size,
+        }
+    }
     /// Prepares a single expression for execution. This involves walking the
     /// expression tree and putting them in the `expr_stack` such that
     /// continuously popping from its back will evaluate the expression. The
     /// results of each expression will be stored by pushing onto `expr_values`.
     pub fn prepare_single_expression(&mut self, heap: &Heap, expr_id: ExpressionId) {
         debug_assert!(self.expr_stack.is_empty());
         self.expr_values.clear(); // May not be empty if last expression result(s) were discarded
         self.serialize_expression(heap, expr_id);
+    }
     /// Prepares multiple expressions for execution (i.e. evaluating all
     /// function arguments or all elements of an array/union literal). Per
     /// expression this works the same as `prepare_single_expression`. However
     /// after each expression is evaluated we insert a `PushValToFront`
     /// instruction
     pub fn prepare_multiple_expressions(&mut self, heap: &Heap, expr_ids: &[ExpressionId]) {
         debug_assert!(self.expr_stack.is_empty());
         self.expr_values.clear();
         for expr_id in expr_ids {
             self.expr_stack.push_back(ExprInstruction::PushValToFront);
             self.serialize_expression(heap, *expr_id);
+        }
+    }
     /// Performs depth-first serialization of expression tree. Let's not care
     /// about performance for a temporary runtime implementation
     fn serialize_expression(&mut self, heap: &Heap, id: ExpressionId) {
         self.expr_stack.push_back(ExprInstruction::EvalExpr(id));
         match &heap[id] {
             Expression::Assignment(expr) => {
                 self.serialize_expression(heap, expr.left);
                 self.serialize_expression(heap, expr.right);
             },
             Expression::Binding(expr) => {
                 self.serialize_expression(heap, expr.bound_to);
                 self.serialize_expression(heap, expr.bound_from);
             },
             Expression::Conditional(expr) => {
                 self.serialize_expression(heap, expr.test);
             },
             Expression::Binary(expr) => {
                 self.serialize_expression(heap, expr.left);
                 self.serialize_expression(heap, expr.right);
             },
             Expression::Unary(expr) => {
                 self.serialize_expression(heap, expr.expression);
             },
             Expression::Indexing(expr) => {
                 self.serialize_expression(heap, expr.index);
                 self.serialize_expression(heap, expr.subject);
             },
             Expression::Slicing(expr) => {
                 self.serialize_expression(heap, expr.from_index);
                 self.serialize_expression(heap, expr.to_index);
                 self.serialize_expression(heap, expr.subject);
             },
             Expression::Select(expr) => {
                 self.serialize_expression(heap, expr.subject);
             },
             Expression::Literal(expr) => {
                 // Here we only care about literals that have subexpressions
                 match &expr.value {
                     Literal::Null | Literal::True | Literal::False |
                     Literal::Character(_) | Literal::String(_) |
                     Literal::Integer(_) | Literal::Enum(_) => {
                         // No subexpressions
                     },
                     Literal::Struct(literal) => {
                         // Note: fields expressions are evaluated in programmer-
                         // specified order. But struct construction expects them
                         // in type-defined order. I might want to come back to
                         // this.
                         let mut _num_pushed = 0;
                         for want_field_idx in 0..literal.fields.len() {
                             for field in &literal.fields {
                                 if field.field_idx == want_field_idx {
                                     _num_pushed += 1;
                                     self.expr_stack.push_back(ExprInstruction::PushValToFront);
                                     self.serialize_expression(heap, field.value);
+                                }
+                            }
+                        }
                         debug_assert_eq!(_num_pushed, literal.fields.len())
                     },
                     Literal::Union(literal) => {
                         for value_expr_id in &literal.values {
                             self.expr_stack.push_back(ExprInstruction::PushValToFront);
                             self.serialize_expression(heap, *value_expr_id);
+                        }
                     },
                     Literal::Array(value_expr_ids) => {
                         for value_expr_id in value_expr_ids {
                             self.expr_stack.push_back(ExprInstruction::PushValToFront);
                             self.serialize_expression(heap, *value_expr_id);
+                        }
                     },
                     Literal::Tuple(value_expr_ids) => {
                         for value_expr_id in value_expr_ids {
                             self.expr_stack.push_back(ExprInstruction::PushValToFront);
                             self.serialize_expression(heap, *value_expr_id);
+                        }
+                    }
+                }
             },
             Expression::Cast(expr) => {
                 self.serialize_expression(heap, expr.subject);
+            }
             Expression::Call(expr) => {
                 for arg_expr_id in &expr.arguments {
                     self.expr_stack.push_back(ExprInstruction::PushValToFront);
                     self.serialize_expression(heap, *arg_expr_id);
+                }
             },
             Expression::Variable(_expr) => {
                 // No subexpressions
+            }
+        }
+    }
+}
 type EvalResult = Result<EvalContinuation, EvalError>;
+pub type EvalResult = Result<EvalContinuation, EvalError>;
 #[derive(Debug)]
 pub enum EvalContinuation {
     // Returned in both sync and non-sync modes
     Stepping,
     // Returned only in sync mode
     BranchInconsistent,
     SyncBlockEnd,
     NewFork,
     BlockFires(PortId),
     BlockGet(PortId),
     Put(PortId, ValueGroup),
     // Returned only in non-sync mode
     ComponentTerminated,
     SyncBlockStart,
     NewComponent(DefinitionId, i32, ValueGroup),
     NewChannel,
+}
 // Note: cloning is fine, methinks. cloning all values and the heap regions then
 // we end up with valid "pointers" to heap regions.
 #[derive(Debug, Clone)]
 pub struct Prompt {
     pub(crate) frames: Vec<Frame>,
     pub(crate) store: Store,
+}
 impl Prompt {
     pub fn new(_types: &TypeTable, heap: &Heap, def: DefinitionId, monomorph_idx: i32, args: ValueGroup) -> Self {
         let mut prompt = Self{
             frames: Vec::new(),
             store: Store::new(),
         };
         // Maybe do typechecking in the future?
         let new_frame = Frame::new(heap, def, monomorph_idx);
         let max_stack_size = new_frame.max_stack_size;
         prompt.frames.push(new_frame);
         args.into_store(&mut prompt.store);
         prompt.store.reserve_stack(max_stack_size);
         prompt
+    }
     /// Big 'ol function right here. Didn't want to break it up unnecessarily.
     /// It consists of, in sequence: executing any expressions that should be
     /// executed before the next statement can be evaluated, then a section that
     /// performs debug printing, and finally a section that takes the next
     /// statement and executes it. If the statement requires any expressions to
     /// be evaluated, then they will be added such that the next time `step` is
     /// called, all of these expressions are indeed evaluated.
     pub(crate) fn step(&mut self, types: &TypeTable, heap: &Heap, modules: &[Module], ctx: &mut impl RunContext) -> EvalResult {
         // Helper function to transfer multiple values from the expression value
         // array into a heap region (e.g. constructing arrays or structs).
         fn transfer_expression_values_front_into_heap(cur_frame: &mut Frame, store: &mut Store, num_values: usize) -> HeapPos {
             let heap_pos = store.alloc_heap();
             // Do the transformation first (because Rust...)
             for val_idx in 0..num_values {
                 cur_frame.expr_values[val_idx] = store.read_take_ownership(cur_frame.expr_values[val_idx].clone());
+            }
             // And now transfer to the heap region
             let values = &mut store.heap_regions[heap_pos as usize].values;
             debug_assert!(values.is_empty());
             values.reserve(num_values);
             for _ in 0..num_values {
                 values.push(cur_frame.expr_values.pop_front().unwrap());
+            }
             heap_pos
+        }
         // Helper function to make sure that an index into an aray is valid.
         fn array_inclusive_index_is_invalid(store: &Store, array_heap_pos: u32, idx: i64) -> bool {
             let array_len = store.heap_regions[array_heap_pos as usize].values.len();
             return idx < 0 || idx >= array_len as i64;
+        }
         fn array_exclusive_index_is_invalid(store: &Store, array_heap_pos: u32, idx: i64) -> bool {
             let array_len = store.heap_regions[array_heap_pos as usize].values.len();
             return idx < 0 || idx > array_len as i64;
+        }
         fn construct_array_error(prompt: &Prompt, modules: &[Module], heap: &Heap, expr_id: ExpressionId, heap_pos: u32, idx: i64) -> EvalError {
             let array_len = prompt.store.heap_regions[heap_pos as usize].values.len();
             return EvalError::new_error_at_expr(
                 prompt, modules, heap, expr_id,
                 format!("index {} is out of bounds: array length is {}", idx, array_len)
+            )
+        }
         // Checking if we're at the end of execution
         let cur_frame = self.frames.last_mut().unwrap();
         if cur_frame.position.is_invalid() {
             if heap[cur_frame.definition].is_function() {
                 todo!("End of function without return, return an evaluation error");
+            }
             return Ok(EvalContinuation::ComponentTerminated);
+        }
         debug_log!("Taking step in '{}'", heap[cur_frame.definition].identifier().value.as_str());
         // Execute all pending expressions
         while !cur_frame.expr_stack.is_empty() {
             let next = cur_frame.expr_stack.pop_back().unwrap();
             debug_log!("Expr stack: {:?}", next);
             match next {
                 ExprInstruction::PushValToFront => {
                     cur_frame.expr_values.rotate_right(1);
                 },
                 ExprInstruction::EvalExpr(expr_id) => {
                     let expr = &heap[expr_id];
                     match expr {
                         Expression::Assignment(expr) => {
                             let to = cur_frame.expr_values.pop_back().unwrap().as_ref();
                             let rhs = cur_frame.expr_values.pop_back().unwrap();
                             // Note: although not pretty, the assignment operator takes ownership
                             // of the right-hand side value when possible. So we do not drop the
                             // rhs's optionally owned heap data.
                             let rhs = self.store.read_take_ownership(rhs);
                             apply_assignment_operator(&mut self.store, to, expr.operation, rhs);
                         },
                         Expression::Binding(_expr) => {
                             let bind_to = cur_frame.expr_values.pop_back().unwrap();
                             let bind_from = cur_frame.expr_values.pop_back().unwrap();
                             let bind_to_heap_pos = bind_to.get_heap_pos();
                             let bind_from_heap_pos = bind_from.get_heap_pos();
                             let result = apply_binding_operator(&mut self.store, bind_to, bind_from);
                             self.store.drop_value(bind_to_heap_pos);
                             self.store.drop_value(bind_from_heap_pos);
                             cur_frame.expr_values.push_back(Value::Bool(result));
                         },
                         Expression::Conditional(expr) => {
                             // Evaluate testing expression, then extend the
                             // expression stack with the appropriate expression
                             let test_result = cur_frame.expr_values.pop_back().unwrap().as_bool();
                             if test_result {
                                 cur_frame.serialize_expression(heap, expr.true_expression);
                             } else {
                                 cur_frame.serialize_expression(heap, expr.false_expression);
+                            }
                         },
                         Expression::Binary(expr) => {
                             let lhs = cur_frame.expr_values.pop_back().unwrap();
                             let rhs = cur_frame.expr_values.pop_back().unwrap();
                             let result = apply_binary_operator(&mut self.store, &lhs, expr.operation, &rhs);
                             cur_frame.expr_values.push_back(result);
                             self.store.drop_value(lhs.get_heap_pos());
                             self.store.drop_value(rhs.get_heap_pos());
                         },
                         Expression::Unary(expr) => {
                             let val = cur_frame.expr_values.pop_back().unwrap();
                             let result = apply_unary_operator(&mut self.store, expr.operation, &val);
                             cur_frame.expr_values.push_back(result);
                             self.store.drop_value(val.get_heap_pos());
                         },
                         Expression::Indexing(_expr) => {
                             // Evaluate index. Never heap allocated so we do
                             // not have to drop it.
                             let index = cur_frame.expr_values.pop_back().unwrap();
                             let index = self.store.maybe_read_ref(&index);
                             debug_assert!(index.is_integer());
                             let index = if index.is_signed_integer() {
                                 index.as_signed_integer() as i64
                             } else {
                                 index.as_unsigned_integer() as i64
                             };
                             let subject = cur_frame.expr_values.pop_back().unwrap();
                             let (deallocate_heap_pos, value_to_push) = match subject {
                                 Value::Ref(value_ref) => {
                                     // Our expression stack value is a reference to something that
                                     // exists in the normal stack/heap. We don't want to deallocate
                                     // this thing. Rather we want to return a reference to it.
                                     let subject = self.store.read_ref(value_ref);
                                     let subject_heap_pos = match subject {
                                         Value::String(v) => *v,
                                         Value::Array(v) => *v,
                                         Value::Message(v) => *v,
                                         _ => unreachable!(),
                                     };
                                     if array_inclusive_index_is_invalid(&self.store, subject_heap_pos, index) {
                                         return Err(construct_array_error(self, modules, heap, expr_id, subject_heap_pos, index));
+                                    }
                                     (None, Value::Ref(ValueId::Heap(subject_heap_pos, index as u32)))
                                 },
                                 _ => {
                                     // Our value lives on the expression stack, hence we need to
                                     // clone whatever we're referring to. Then drop the subject.
                                     let subject_heap_pos = match &subject {
                                         Value::String(v) => *v,
                                         Value::Array(v) => *v,
                                         Value::Message(v) => *v,
                                         _ => unreachable!(),
                                     };
                                     if array_inclusive_index_is_invalid(&self.store, subject_heap_pos, index) {
                                         return Err(construct_array_error(self, modules, heap, expr_id, subject_heap_pos, index));
+                                    }
                                     let subject_indexed = Value::Ref(ValueId::Heap(subject_heap_pos, index as u32));
                                     (Some(subject_heap_pos), self.store.clone_value(subject_indexed))
                                 },
                             };
                             cur_frame.expr_values.push_back(value_to_push);
                             self.store.drop_value(deallocate_heap_pos);
                         },
                         Expression::Slicing(expr) => {
                             // Evaluate indices
                             let from_index = cur_frame.expr_values.pop_back().unwrap();
                             let from_index = self.store.maybe_read_ref(&from_index);
                             let to_index = cur_frame.expr_values.pop_back().unwrap();
                             let to_index = self.store.maybe_read_ref(&to_index);
                             debug_assert!(from_index.is_integer() && to_index.is_integer());
                             let from_index = if from_index.is_signed_integer() {
                                 from_index.as_signed_integer()
                             } else {
                                 from_index.as_unsigned_integer() as i64
                             };
                             let to_index = if to_index.is_signed_integer() {
                                 to_index.as_signed_integer()
                             } else {
                                 to_index.as_unsigned_integer() as i64
                             };
                             // Dereference subject if needed
                             let subject = cur_frame.expr_values.pop_back().unwrap();
                             let deref_subject = self.store.maybe_read_ref(&subject);
                             // Slicing needs to produce a copy anyway (with the
                             // current evaluator implementation)
                             enum ValueKind{ Array, String, Message }
                             let (value_kind, array_heap_pos) = match deref_subject {
                                 Value::Array(v) => (ValueKind::Array, *v),
                                 Value::String(v) => (ValueKind::String, *v),
                                 Value::Message(v) => (ValueKind::Message, *v),
                                 _ => unreachable!()
                             };
                             if array_inclusive_index_is_invalid(&self.store, array_heap_pos, from_index) {
                                 return Err(construct_array_error(self, modules, heap, expr.from_index, array_heap_pos, from_index));
+                            }
                             if array_exclusive_index_is_invalid(&self.store, array_heap_pos, to_index) {
                                 return Err(construct_array_error(self, modules, heap, expr.to_index, array_heap_pos, to_index));
+                            }
                             // Again: would love to push directly, but rust...
                             let new_heap_pos = self.store.alloc_heap();
                             debug_assert!(self.store.heap_regions[new_heap_pos as usize].values.is_empty());
                             if to_index > from_index {
                                 let from_index = from_index as usize;
                                 let to_index = to_index as usize;
                                 let mut values = Vec::with_capacity(to_index - from_index);
                                 for idx in from_index..to_index {
                                     let value = self.store.heap_regions[array_heap_pos as usize].values[idx].clone();
                                     values.push(self.store.clone_value(value));
+                                }
                                 self.store.heap_regions[new_heap_pos as usize].values = values;
                             } // else: empty range
                             cur_frame.expr_values.push_back(match value_kind {
                                 ValueKind::Array => Value::Array(new_heap_pos),
                                 ValueKind::String => Value::String(new_heap_pos),
                                 ValueKind::Message => Value::Message(new_heap_pos),
                             });
                             // Dropping the original subject, because we don't
                             // want to drop something on the stack
                             self.store.drop_value(subject.get_heap_pos());
                         },
                         Expression::Select(expr) => {
                             let subject= cur_frame.expr_values.pop_back().unwrap();
                             let mono_data = types.get_procedure_monomorph(cur_frame.monomorph_idx);
                             let field_idx = mono_data.expr_data[expr.unique_id_in_definition as usize].field_or_monomorph_idx as u32;
                             // Note: same as above: clone if value lives on expr stack, simply
                             // refer to it if it already lives on the stack/heap.
                             let (deallocate_heap_pos, value_to_push) = match subject {
                                 Value::Ref(value_ref) => {
                                     let subject = self.store.read_ref(value_ref);
                                     let subject_heap_pos = match expr.kind {
                                         SelectKind::StructField(_) => subject.as_struct(),
                                         SelectKind::TupleMember(_) => subject.as_tuple(),
                                     };
                                     (None, Value::Ref(ValueId::Heap(subject_heap_pos, field_idx)))
                                 },
                                 _ => {
                                     let subject_heap_pos = match expr.kind {
                                         SelectKind::StructField(_) => subject.as_struct(),
                                         SelectKind::TupleMember(_) => subject.as_tuple(),
                                     };
                                     let subject_indexed = Value::Ref(ValueId::Heap(subject_heap_pos, field_idx));
                                     (Some(subject_heap_pos), self.store.clone_value(subject_indexed))
                                 },
                             };
                             cur_frame.expr_values.push_back(value_to_push);
                             self.store.drop_value(deallocate_heap_pos);
                         },
                         Expression::Literal(expr) => {
                             let value = match &expr.value {
                                 Literal::Null => Value::Null,
                                 Literal::True => Value::Bool(true),
                                 Literal::False => Value::Bool(false),
                                 Literal::Character(lit_value) => Value::Char(*lit_value),
                                 Literal::String(lit_value) => {
                                     let heap_pos = self.store.alloc_heap();
                                     let values = &mut self.store.heap_regions[heap_pos as usize].values;
                                     let value = lit_value.as_str();
                                     debug_assert!(values.is_empty());
                                     values.reserve(value.len());
                                     for character in value.as_bytes() {
                                         debug_assert!(character.is_ascii());
                                         values.push(Value::Char(*character as char));
+                                    }
                                     Value::String(heap_pos)
+                                }
                                 Literal::Integer(lit_value) => {
                                     use ConcreteTypePart as CTP;
                                     let def_types = types.get_procedure_monomorph(cur_frame.monomorph_idx);
                                     let concrete_type = &def_types.expr_data[expr.unique_id_in_definition as usize].expr_type;
                                     debug_assert_eq!(concrete_type.parts.len(), 1);
                                     match concrete_type.parts[0] {
                                         CTP::UInt8  => Value::UInt8(lit_value.unsigned_value as u8),
                                         CTP::UInt16 => Value::UInt16(lit_value.unsigned_value as u16),
                                         CTP::UInt32 => Value::UInt32(lit_value.unsigned_value as u32),
                                         CTP::UInt64 => Value::UInt64(lit_value.unsigned_value as u64),
                                         CTP::SInt8  => Value::SInt8(lit_value.unsigned_value as i8),
                                         CTP::SInt16 => Value::SInt16(lit_value.unsigned_value as i16),
                                         CTP::SInt32 => Value::SInt32(lit_value.unsigned_value as i32),
                                         CTP::SInt64 => Value::SInt64(lit_value.unsigned_value as i64),
                                         _ => unreachable!("got concrete type {:?} for integer literal at expr {:?}", concrete_type, expr_id),
+                                    }
+                                }
                                 Literal::Struct(lit_value) => {
                                     let heap_pos = transfer_expression_values_front_into_heap(
                                         cur_frame, &mut self.store, lit_value.fields.len()
                                     );
                                     Value::Struct(heap_pos)
+                                }
                                 Literal::Enum(lit_value) => {
                                     Value::Enum(lit_value.variant_idx as i64)
+                                }
                                 Literal::Union(lit_value) => {
                                     let heap_pos = transfer_expression_values_front_into_heap(
                                         cur_frame, &mut self.store, lit_value.values.len()
                                     );
                                     Value::Union(lit_value.variant_idx as i64, heap_pos)
+                                }
                                 Literal::Array(lit_value) => {
                                     let heap_pos = transfer_expression_values_front_into_heap(
                                         cur_frame, &mut self.store, lit_value.len()
                                     );
                                     Value::Array(heap_pos)
+                                }
                                 Literal::Tuple(lit_value) => {
                                     let heap_pos = transfer_expression_values_front_into_heap(
                                         cur_frame, &mut self.store, lit_value.len()
                                     );
                                     Value::Tuple(heap_pos)
+                                }
                             };
                             cur_frame.expr_values.push_back(value);
                         },
                         Expression::Cast(expr) => {
                             let mono_data = types.get_procedure_monomorph(cur_frame.monomorph_idx);
                             let output_type = &mono_data.expr_data[expr.unique_id_in_definition as usize].expr_type;
                             // Typechecking reduced this to two cases: either we
                             // have casting noop (same types), or we're casting
                             // between integer/bool/char types.
                             let subject = cur_frame.expr_values.pop_back().unwrap();
                             match apply_casting(&mut self.store, output_type, &subject) {
                                 Ok(value) => cur_frame.expr_values.push_back(value),
                                 Err(msg) => {
                                     return Err(EvalError::new_error_at_expr(self, modules, heap, expr.this.upcast(), msg));
+                                }
+                            }
                             self.store.drop_value(subject.get_heap_pos());
+                        }
                         Expression::Call(expr) => {
                             // If we're dealing with a builtin we don't do any
                             // fancy shenanigans at all, just push the result.
                             match expr.method {
                                 Method::Get => {
                                     let value = cur_frame.expr_values.pop_front().unwrap();
                                     let value = self.store.maybe_read_ref(&value).clone();
                                     let port_id = if let Value::Input(port_id) = value {
                                         port_id
                                     } else {
                                         unreachable!("executor calling 'get' on value {:?}", value)
                                     };
                                     match ctx.performed_get(port_id) {
                                         Some(result) => {
                                             // We have the result. Merge the `ValueGroup` with the
                                             // stack/heap storage.
                                             debug_assert_eq!(result.values.len(), 1);
                                             result.into_stack(&mut cur_frame.expr_values, &mut self.store);
                                         },
                                         None => {
                                             // Don't have the result yet, prepare the expression to
                                             // get run again after we've received a message.
                                             cur_frame.expr_values.push_front(value.clone());
                                             cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
                                             return Ok(EvalContinuation::BlockGet(port_id));
+                                        }
+                                    }
                                 },
                                 Method::Put => {
                                     let port_value = cur_frame.expr_values.pop_front().unwrap();
                                     let deref_port_value = self.store.maybe_read_ref(&port_value).clone();
                                     let port_id = if let Value::Output(port_id) = deref_port_value {
                                         port_id
                                     } else {
                                         unreachable!("executor calling 'put' on value {:?}", deref_port_value)
                                     };
                                     let msg_value = cur_frame.expr_values.pop_front().unwrap();
                                     let deref_msg_value = self.store.maybe_read_ref(&msg_value).clone();
                                     if ctx.performed_put(port_id) {
                                         // We're fine, deallocate in case the expression value stack
                                         // held an owned value
                                         self.store.drop_value(msg_value.get_heap_pos());
                                     } else {
                                         // Prepare to execute again
                                         cur_frame.expr_values.push_front(msg_value);
                                         cur_frame.expr_values.push_front(port_value);
                                         cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
                                         let value_group = ValueGroup::from_store(&self.store, &[deref_msg_value]);
                                         return Ok(EvalContinuation::Put(port_id, value_group));
+                                    }
                                 },
                                 Method::Fires => {
                                     let port_value = cur_frame.expr_values.pop_front().unwrap();
                                     let port_value_deref = self.store.maybe_read_ref(&port_value).clone();
                                     let port_id = match port_value_deref {
                                         Value::Input(port_id) => port_id,
                                         Value::Output(port_id) => port_id,
                                         _ => unreachable!("executor calling 'fires' on value {:?}", port_value_deref),
                                     };
                                     match ctx.fires(port_id) {
                                         None => {
                                             cur_frame.expr_values.push_front(port_value);
                                             cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
                                             return Ok(EvalContinuation::BlockFires(port_id));
                                         },
                                         Some(value) => {
                                             cur_frame.expr_values.push_back(value);
+                                        }
+                                    }
                                 },
                                 Method::Create => {
                                     let length_value = cur_frame.expr_values.pop_front().unwrap();
                                     let length_value = self.store.maybe_read_ref(&length_value);
                                     let length = if length_value.is_signed_integer() {
                                         let length_value = length_value.as_signed_integer();
                                         if length_value < 0 {
                                             return Err(EvalError::new_error_at_expr(
                                                 self, modules, heap, expr_id,
                                                 format!("got length '{}', can only create a message with a non-negative length", length_value)
                                             ));
+                                        }
                                         length_value as u64
                                     } else {
                                         debug_assert!(length_value.is_unsigned_integer());
                                         length_value.as_unsigned_integer()
                                     };
                                     let heap_pos = self.store.alloc_heap();
                                     let values = &mut self.store.heap_regions[heap_pos as usize].values;
                                     debug_assert!(values.is_empty());
                                     values.resize(length as usize, Value::UInt8(0));
                                     cur_frame.expr_values.push_back(Value::Message(heap_pos));
                                 },
                                 Method::Length => {
                                     let value = cur_frame.expr_values.pop_front().unwrap();
                                     let value_heap_pos = value.get_heap_pos();
                                     let value = self.store.maybe_read_ref(&value);
                                     let heap_pos = match value {
                                         Value::Array(pos) => *pos,
                                         Value::String(pos) => *pos,
                                         _ => unreachable!("length(...) on {:?}", value),
                                     };
                                     let len = self.store.heap_regions[heap_pos as usize].values.len();
                                     // TODO: @PtrInt
                                     cur_frame.expr_values.push_back(Value::UInt32(len as u32));
                                     self.store.drop_value(value_heap_pos);
                                 },
                                 Method::Assert => {
                                     let value = cur_frame.expr_values.pop_front().unwrap();
                                     let value = self.store.maybe_read_ref(&value).clone();
                                     if !value.as_bool() {
                                         return Ok(EvalContinuation::BranchInconsistent)
+                                    }
                                 },
                                 Method::Print => {
                                     // Convert the runtime-variant of a string
                                     // into an actual string.
                                     let value = cur_frame.expr_values.pop_front().unwrap();
                                     let value_heap_pos = value.as_string();
                                     let elements = &self.store.heap_regions[value_heap_pos as usize].values;
                                     let mut message = String::with_capacity(elements.len());
                                     for element in elements {
                                         message.push(element.as_char());
+                                    }
                                     // Drop the heap-allocated value from the
                                     // store
                                     self.store.drop_heap_pos(value_heap_pos);
                                     println!("{}", message);
                                 },
                                 Method::UserComponent => {
                                     // This is actually handled by the evaluation
                                     // of the statement.
                                     debug_assert_eq!(heap[expr.definition].parameters().len(), cur_frame.expr_values.len());
                                     debug_assert_eq!(heap[cur_frame.position].as_new().expression, expr.this)
                                 },
                                 Method::UserFunction => {
                                     // Push a new frame. Note that all expressions have
                                     // been pushed to the front, so they're in the order
                                     // of the definition.
                                     let num_args = expr.arguments.len();
                                     // Determine stack boundaries
                                     let cur_stack_boundary = self.store.cur_stack_boundary;
                                     let new_stack_boundary = self.store.stack.len();
                                     // Push new boundary and function arguments for new frame
                                     self.store.stack.push(Value::PrevStackBoundary(cur_stack_boundary as isize));
                                     for _ in 0..num_args {
                                         let argument = self.store.read_take_ownership(cur_frame.expr_values.pop_front().unwrap());
                                         self.store.stack.push(argument);
+                                    }
                                     // Determine the monomorph index of the function we're calling
                                     let mono_data = types.get_procedure_monomorph(cur_frame.monomorph_idx);
                                     let call_data = &mono_data.expr_data[expr.unique_id_in_definition as usize];
                                     // Push the new frame and reserve its stack size
                                     let new_frame = Frame::new(heap, expr.definition, call_data.field_or_monomorph_idx);
                                     let new_stack_size = new_frame.max_stack_size;
                                     self.frames.push(new_frame);
                                     self.store.cur_stack_boundary = new_stack_boundary;
                                     self.store.reserve_stack(new_stack_size);
                                     // To simplify the logic a little bit we will now
                                     // return and ask our caller to call us again
                                     return Ok(EvalContinuation::Stepping);
                                 },
+                            }
                         },
                         Expression::Variable(expr) => {
                             let variable = &heap[expr.declaration.unwrap()];
                             let ref_value = if expr.used_as_binding_target {
                                 Value::Binding(variable.unique_id_in_scope as StackPos)
                             } else {
                                 Value::Ref(ValueId::Stack(variable.unique_id_in_scope as StackPos))
                             };
                             cur_frame.expr_values.push_back(ref_value);
+                        }
+                    }
+                }
+            }
+        }
         debug_log!("Frame [{:?}] at {:?}", cur_frame.definition, cur_frame.position);
         if debug_enabled!() {
             debug_log!("Expression value stack (size = {}):", cur_frame.expr_values.len());
             for (_stack_idx, _stack_val) in cur_frame.expr_values.iter().enumerate() {
                 debug_log!("  [{:03}] {:?}", _stack_idx, _stack_val);
+            }
             debug_log!("Stack (size = {}):", self.store.stack.len());
             for (_stack_idx, _stack_val) in self.store.stack.iter().enumerate() {
                 debug_log!("  [{:03}] {:?}", _stack_idx, _stack_val);
+            }
             debug_log!("Heap:");
             for (_heap_idx, _heap_region) in self.store.heap_regions.iter().enumerate() {
                 let _is_free = self.store.free_regions.iter().any(|idx| *idx as usize == _heap_idx);
                 debug_log!("  [{:03}] in_use: {}, len: {}, vals: {:?}", _heap_idx, !_is_free, _heap_region.values.len(), &_heap_region.values);
+            }
+        }
         // No (more) expressions to evaluate. So evaluate statement (that may
         // depend on the result on the last evaluated expression(s))
         let stmt = &heap[cur_frame.position];
         let return_value = match stmt {
             Statement::Block(stmt) => {
                 debug_assert!(stmt.statements.is_empty() || stmt.next == stmt.statements[0]);
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::Stepping)
             },
             Statement::EndBlock(stmt) => {
                 let block = &heap[stmt.start_block];
                 self.store.clear_stack(block.first_unique_id_in_scope as usize);
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::Stepping)
             },
             Statement::Local(stmt) => {
                 match stmt {
                     LocalStatement::Memory(stmt) => {
                         if cfg!(debug_assertions) {
                             let variable = &heap[stmt.variable];
                             debug_assert!(match self.store.read_ref(ValueId::Stack(variable.unique_id_in_scope as u32)) {
                                 Value::Unassigned => false,
                                 _ => true,
                             });
+                        }
                         cur_frame.position = stmt.next;
                         Ok(EvalContinuation::Stepping)
                     },
                     LocalStatement::Channel(stmt) => {
                         // Need to create a new channel by requesting it from
                         // the runtime.
                         match ctx.created_channel() {
                             None => {
                                 // No channel is pending. So request one
                                 Ok(EvalContinuation::NewChannel)
                             },
                             Some((put_port, get_port)) => {
                                 self.store.write(ValueId::Stack(heap[stmt.from].unique_id_in_scope as u32), put_port);
                                 self.store.write(ValueId::Stack(heap[stmt.to].unique_id_in_scope as u32), get_port);
                                 cur_frame.position = stmt.next;
                                 Ok(EvalContinuation::Stepping)
+                            }
+                        }
+                    }
+                }
             },
             Statement::Labeled(stmt) => {
                 cur_frame.position = stmt.body;
                 Ok(EvalContinuation::Stepping)
             },
             Statement::If(stmt) => {
                 debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for if statement");
                 let test_value = cur_frame.expr_values.pop_back().unwrap();
                 let test_value = self.store.maybe_read_ref(&test_value).as_bool();
                 if test_value {
                     cur_frame.position = stmt.true_body.upcast();
                 } else if let Some(false_body) = stmt.false_body {
                     cur_frame.position = false_body.upcast();
                 } else {
                     // Not true, and no false body
                     cur_frame.position = stmt.end_if.upcast();
+                }
                 Ok(EvalContinuation::Stepping)
             },
             Statement::EndIf(stmt) => {
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::Stepping)
             },
             Statement::While(stmt) => {
                 debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for while statement");
                 let test_value = cur_frame.expr_values.pop_back().unwrap();
                 let test_value = self.store.maybe_read_ref(&test_value).as_bool();
                 if test_value {
                     cur_frame.position = stmt.body.upcast();
                 } else {
                     cur_frame.position = stmt.end_while.upcast();
+                }
                 Ok(EvalContinuation::Stepping)
             },
             Statement::EndWhile(stmt) => {
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::Stepping)
             },
             Statement::Break(stmt) => {
                 cur_frame.position = stmt.target.upcast();
                 Ok(EvalContinuation::Stepping)
             },
             Statement::Continue(stmt) => {
                 cur_frame.position = stmt.target.upcast();
                 Ok(EvalContinuation::Stepping)
             },
             Statement::Synchronous(stmt) => {
                 cur_frame.position = stmt.body.upcast();
                 Ok(EvalContinuation::SyncBlockStart)
             },
             Statement::EndSynchronous(stmt) => {
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::SyncBlockEnd)
             },
             Statement::Fork(stmt) => {
                 if stmt.right_body.is_none() {
                     // No reason to fork
                     cur_frame.position = stmt.left_body.upcast();
                 } else {
                     // Need to fork
                     if let Some(go_left) = ctx.performed_fork() {
                         // Runtime has created a fork
                         if go_left {
                             cur_frame.position = stmt.left_body.upcast();
                         } else {
                             cur_frame.position = stmt.right_body.unwrap().upcast();
+                        }
                     } else {
                         // Request the runtime to create a fork of the current
                         // branch
                         return Ok(EvalContinuation::NewFork);
+                    }
+                }
                 Ok(EvalContinuation::Stepping)
             },
             Statement::EndFork(stmt) => {
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::Stepping)
             },
             Statement::Select(_stmt) => {
                 todo!("implement select evaluation")
             },
             Statement::EndSelect(stmt) => {
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::Stepping)
             },
             Statement::Return(_stmt) => {
                 debug_assert!(heap[cur_frame.definition].is_function());
                 debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for return statement");
                 // The preceding frame has executed a call, so is expecting the
                 // return expression on its expression value stack. Note that
                 // we may be returning a reference to something on our stack,
                 // so we need to read that value and clone it.
                 let return_value = cur_frame.expr_values.pop_back().unwrap();
                 let return_value = match return_value {
                     Value::Ref(value_id) => self.store.read_copy(value_id),
                     _ => return_value,
                 };
                 // Pre-emptively pop our stack frame
                 self.frames.pop();
                 // Clean up our section of the stack
                 self.store.clear_stack(0);
                 self.store.stack.truncate(self.store.cur_stack_boundary + 1);
                 let prev_stack_idx = self.store.stack.pop().unwrap().as_stack_boundary();
                 // TODO: Temporary hack for testing, remove at some point
                 if self.frames.is_empty() {
                     debug_assert!(prev_stack_idx == -1);
                     debug_assert!(self.store.stack.len() == 0);
                     self.store.stack.push(return_value);
                     return Ok(EvalContinuation::ComponentTerminated);
+                }
                 debug_assert!(prev_stack_idx >= 0);
                 // Return to original state of stack frame
                 self.store.cur_stack_boundary = prev_stack_idx as usize;
                 let cur_frame = self.frames.last_mut().unwrap();
                 cur_frame.expr_values.push_back(return_value);
                 // We just returned to the previous frame, which might be in
                 // the middle of evaluating expressions for a particular
                 // statement. So we don't want to enter the code below.
                 return Ok(EvalContinuation::Stepping);
             },
             Statement::Goto(stmt) => {
                 cur_frame.position = stmt.target.upcast();
                 Ok(EvalContinuation::Stepping)
             },
             Statement::New(stmt) => {
                 let call_expr = &heap[stmt.expression];
                 debug_assert!(heap[call_expr.definition].is_component());
                 debug_assert_eq!(
                     cur_frame.expr_values.len(), heap[call_expr.definition].parameters().len(),
                     "mismatch in expr stack size and number of arguments for new statement"
                 );
                 let mono_data = types.get_procedure_monomorph(cur_frame.monomorph_idx);
                 let expr_data = &mono_data.expr_data[call_expr.unique_id_in_definition as usize];
                 // Note that due to expression value evaluation they exist in
                 // reverse order on the stack.
                 // TODO: Revise this code, keep it as is to be compatible with current runtime
                 let mut args = Vec::new();
                 while let Some(value) = cur_frame.expr_values.pop_front() {
                     args.push(value);
+                }
                 // Construct argument group, thereby copying heap regions
                 let argument_group = ValueGroup::from_store(&self.store, &args);
                 // println!("Creating {} with\n{:#?}", heap[call_expr.definition].identifier().value.as_str(), argument_group);
                 // Clear any heap regions
                 for arg in &args {
                     self.store.drop_value(arg.get_heap_pos());
+                }
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::NewComponent(call_expr.definition, expr_data.field_or_monomorph_idx, argument_group))
             },
             Statement::Expression(stmt) => {
                 // The expression has just been completely evaluated. Some
                 // values might have remained on the expression value stack.
                 // cur_frame.expr_values.clear(); PROPER CLEARING
                 cur_frame.position = stmt.next;
                 Ok(EvalContinuation::Stepping)
             },
         };
         assert!(
             cur_frame.expr_values.is_empty(),
             "This is a debugging assertion that will fail if you perform expressions without \
             assigning to anything. This should be completely valid, and this assertion should be \
             replaced by something that clears the expression values if needed, but I'll keep this \
             in for now for debugging purposes."
         );
         // If the next statement requires evaluating expressions then we push
         // these onto the expression stack. This way we will evaluate this
         // stack in the next loop, then evaluate the statement using the result
         // from the expression evaluation.
         if !cur_frame.position.is_invalid() {
             let stmt = &heap[cur_frame.position];
             match stmt {
                 Statement::Local(stmt) => {
                     if let LocalStatement::Memory(stmt) = stmt {
                         // Setup as unassigned, when we execute the memory
                         // statement (after evaluating expression), it should no
                         // longer be `Unassigned`.
                         let variable = &heap[stmt.variable];
                         self.store.write(ValueId::Stack(variable.unique_id_in_scope as u32), Value::Unassigned);
                         cur_frame.prepare_single_expression(heap, stmt.initial_expr.upcast());
+                    }
                 },
                 Statement::If(stmt) => cur_frame.prepare_single_expression(heap, stmt.test),
                 Statement::While(stmt) => cur_frame.prepare_single_expression(heap, stmt.test),
                 Statement::Return(stmt) => {
                     debug_assert_eq!(stmt.expressions.len(), 1); // TODO: @ReturnValues
                     cur_frame.prepare_single_expression(heap, stmt.expressions[0]);
                 },
                 Statement::New(stmt) => {
                     // Note that we will end up not evaluating the call itself.
                     // Rather we will evaluate its expressions and then
                     // instantiate the component upon reaching the "new" stmt.
                     let call_expr = &heap[stmt.expression];
                     cur_frame.prepare_multiple_expressions(heap, &call_expr.arguments);
                 },
                 Statement::Expression(stmt) => {
                     cur_frame.prepare_single_expression(heap, stmt.expression);
+                }
                 _ => {},
+            }
+        }
         return_value
+    }
     /// Constructs an error at the current expression that lives at the top of
     /// the expression stack. Falls back to constructing an error at the current
     /// statement if there is no expression.
     pub(crate) fn new_error_at_expr(&self, modules: &[Module], heap: &Heap, error_message: String) -> EvalError {
         let last_frame = self.frames.last().unwrap();
         for instruction in last_frame.expr_stack.iter().rev() {
             if let ExprInstruction::EvalExpr(expression_id) = instruction {
                 return EvalError::new_error_at_expr(
                     self, modules, heap, *expression_id, error_message
                 );
+            }
+        }
         // If here then expression stack was empty (cannot have just rotate
         // instructions)
         panic!("attempted to construct evaluation error without any expressions to evaluate in frame");
+    }
+}
@@ \ No newline at end of file @@

src/protocol/eval/mod.rs

➞

Show inline comments

 /// eval
 ///
 /// Evaluator of the generated AST. Note that we use some misappropriated terms
 /// to describe where values live and what they do. This is a temporary
 /// implementation of an evaluator until some kind of appropriate bytecode or
 /// machine code is generated.
 ///
 /// Code is always executed within a "frame". For Reowolf the first frame is
 /// usually an executed component. All subsequent frames are function calls.
 /// Simple values live on the "stack". Each variable/parameter has a place on
 /// the stack where its values are stored. If the value is not a primitive, then
 /// its value will be stored in the "heap". Expressions are treated differently
 /// and use a separate "stack" for their evaluation.
 ///
 /// Since this is a value-based language, most values are copied. One has to be
 /// careful with values that reside in the "heap" and make sure that copies are
 /// properly removed from the heap..
 ///
 /// Just to reiterate: this is a temporary wasteful implementation. A proper
 /// implementation would fully fill out the type table with alignment/size/
 /// offset information and lay out bytecode.
 pub(crate) mod value;
 pub(crate) mod store;
 pub(crate) mod executor;
 pub(crate) mod error;
 pub use error::EvalError;
 pub use value::{PortId, Value, ValueGroup};
 pub use executor::{EvalContinuation, Prompt};
+pub use executor::{EvalContinuation, EvalResult, Prompt};

src/runtime2/communication.rs

➞

Show inline comments

 use super::runtime::*;
 #[derive(Copy, Clone)]
 pub struct PortId(pub u32);
 impl PortId {
     pub fn new_invalid() -> Self {
         return Self(u32::MAX);
+    }
+}
 pub struct Peer {
     pub id: CompId,
     pub(crate) handle: CompHandle,
+}
 pub enum PortKind {
     Putter,
     Getter,
+}
 pub enum PortState {
     Open,
     Closed,
+}
 pub struct Port {
     pub self_id: PortId,
     pub peer_id: PortId,
     pub kind: PortKind,
     pub state: PortState,
     pub local_peer_index: u32,
+}
 /// Public inbox: accessible by all threads. Essentially a MPSC channel
 pub struct InboxPublic {
+}
@@ \ No newline at end of file @@

src/runtime2/component.rs

➞

Show inline comments

 use crate::protocol::*;
 use crate::protocol::eval::{
     PortId as EvalPortId, Prompt,
     ValueGroup, Value,
     EvalContinuation, EvalResult, EvalError
 };
 use super::runtime::*;
 use super::scheduler::SchedulerCtx;
 use super::communication::*;
 pub enum CompScheduling {
     Immediate,
     Requeue,
     Sleep,
     Exit,
+}
 pub struct CompCtx {
     pub id: CompId,
     pub ports: Vec<Port>,
     pub peers: Vec<Peer>,
     pub messages: Vec<ValueGroup>, // same size as "ports"
+}
 impl CompCtx {
     fn take_message(&mut self, port_id: PortId) -> Option<ValueGroup> {
         let old_value = &mut self.messages[port_id.0 as usize];
         if old_value.values.is_empty() {
             return None;
+        }
         // Replace value in array with an empty one
         let mut message = ValueGroup::new_stack(Vec::new());
         std::mem::swap(old_value, &mut message);
         return Some(message);
+    }
     fn find_peer(&self, port_id: PortId) -> &Peer {
         let port_info = &self.ports[port_id.0 as usize];
         let peer_info = &self.peers[port_info.local_peer_index as usize];
         return peer_info;
+    }
+}
 pub enum ExecStmt {
     CreatedChannel((Value, Value)),
     PerformedPut,
     PerformedGet(ValueGroup),
     None,
+}
 impl ExecStmt {
     fn take(&mut self) -> ExecStmt {
         let mut value = ExecStmt::None;
         std::mem::swap(self, &mut value);
         return value;
+    }
     fn is_none(&self) -> bool {
         match self {
             ExecStmt::None => return true,
             _ => return false,
+        }
+    }
+}
 pub struct ExecCtx {
     stmt: ExecStmt,
+}
 impl RunContext for ExecCtx {
     fn performed_put(&mut self, _port: EvalPortId) -> bool {
         match self.stmt.take() {
             ExecStmt::None => return false,
             ExecStmt::PerformedPut => return true,
             _ => unreachable!(),
+        }
+    }
     fn performed_get(&mut self, _port: EvalPortId) -> Option<ValueGroup> {
         match self.stmt.take() {
             ExecStmt::None => return None,
             ExecStmt::PerformedGet(value) => return Some(value),
             _ => unreachable!(),
+        }
+    }
     fn fires(&mut self, _port: EvalPortId) -> Option<Value> {
         todo!("remove fires")
+    }
     fn performed_fork(&mut self) -> Option<bool> {
         todo!("remove fork")
+    }
     fn created_channel(&mut self) -> Option<(Value, Value)> {
         match self.stmt.take() {
             ExecStmt::None => return None,
             ExecStmt::CreatedChannel(ports) => return Some(ports),
             _ => unreachable!(),
+        }
+    }
+}
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub(crate) enum Mode {
     NonSync,
     Sync,
     BlockedGet,
     BlockedPut,
+}
 pub(crate) struct CompPDL {
     pub mode: Mode,
     pub mode_port: PortId, // when blocked on a port
     pub mode_value: ValueGroup, // when blocked on a put
     pub prompt: Prompt,
     pub exec_ctx: ExecCtx,
+}
 impl CompPDL {
     pub(crate) fn new(initial_state: Prompt) -> Self {
         return Self{
             mode: Mode::NonSync,
             mode_port: PortId::new_invalid(),
             mode_value: ValueGroup::default(),
             prompt: initial_state,
             exec_ctx: ExecCtx{
                 stmt: ExecStmt::None,
+            }
+        }
+    }
     pub(crate) fn run(&mut self, sched_ctx: &SchedulerCtx, comp_ctx: &mut CompCtx) -> Result<CompScheduling, EvalError> {
         use EvalContinuation as EC;
         let run_result = self.execute_prompt(&sched_ctx)?;
         match run_result {
             EC::Stepping => unreachable!(), // execute_prompt runs until this is no longer returned
             EC::BranchInconsistent | EC::NewFork | EC::BlockFires(_) => todo!("remove these"),
             // Results that can be returned in sync mode
             EC::SyncBlockEnd => {
                 debug_assert_eq!(self.mode, Mode::Sync);
                 self.handle_sync_end(sched_ctx, comp_ctx);
             },
             EC::BlockGet(port_id) => {
                 debug_assert_eq!(self.mode, Mode::Sync);
                 let port_id = transform_port_id(port_id);
                 if let Some(message) = comp_ctx.take_message(port_id) {
                     // We can immediately receive and continue
                     debug_assert!(self.exec_ctx.stmt.is_none());
                     self.exec_ctx.stmt = ExecStmt::PerformedGet(message);
                     return Ok(CompScheduling::Immediate);
                 } else {
                     // We need to wait
                     self.mode = Mode::BlockedGet;
                     self.mode_port = port_id;
                     return Ok(CompScheduling::Sleep);
+                }
             },
             EC::Put(port_id, value) => {
                 debug_assert_eq!(self.mode, Mode::Sync);
                 let port_id = transform_port_id(port_id);
                 let peer = comp_ctx.find_peer(port_id);
             },
             // Results that can be returned outside of sync mode
             EC::ComponentTerminated => {
                 debug_assert_eq!(self.mode, Mode::NonSync);
             },
             EC::SyncBlockStart => {
                 debug_assert_eq!(self.mode, Mode::NonSync);
                 self.handle_sync_start(sched_ctx, comp_ctx);
             },
             EC::NewComponent(definition_id, monomorph_idx, arguments) => {
                 debug_assert_eq!(self.mode, Mode::NonSync);
             },
             EC::NewChannel => {
                 debug_assert_eq!(self.mode, Mode::NonSync);
+            }
+        }
         return Ok(CompScheduling::Sleep);
+    }
     fn execute_prompt(&mut self, sched_ctx: &SchedulerCtx) -> EvalResult {
         let mut step_result = EvalContinuation::Stepping;
         while let EvalContinuation::Stepping = step_result {
             step_result = self.prompt.step(
                 &sched_ctx.runtime.protocol.types, &sched_ctx.runtime.protocol.heap,
                 &sched_ctx.runtime.protocol.modules, &mut self.exec_ctx,
             )?;
+        }
         return Ok(step_result)
+    }
     fn handle_sync_start(&mut self, sched_ctx: &SchedulerCtx, comp_ctx: &mut CompCtx) {
+    }
     fn handle_sync_end(&mut self, sched_ctx: &SchedulerCtx, comp_ctx: &mut CompCtx) {
+    }
+}
 #[inline]
 fn transform_port_id(port_id: EvalPortId) -> PortId {
     return PortId(port_id.id);
+}
@@ \ No newline at end of file @@

src/runtime2/mod.rs

➞

Show inline comments

+mod store;
 mod runtime;
 mod component;
 mod communication;
@@ \ No newline at end of file @@
 mod communication;
 mod scheduler;
@@ \ No newline at end of file @@

src/runtime2/runtime.rs

➞

Show inline comments

 use std::mem::{size_of, align_of, transmute};
 use std::alloc::{alloc, dealloc, Layout};
 use std::sync::Arc;
 use std::sync::atomic::{AtomicU32, AtomicUsize, Ordering};
 use std::sync::{Arc, Mutex, Condvar};
 use std::sync::atomic::{AtomicU32, AtomicBool, Ordering};
 use std::collections::VecDeque;
 use crate::protocol::*;
 use super::component::{CompCtx, CompPDL};
 use super::store::ComponentStore;
 // -----------------------------------------------------------------------------
 // Component
 // -----------------------------------------------------------------------------
 /// Key to a component. Type system somewhat ensures that there can only be one
 /// of these. Only with a key one may retrieve privately-accessible memory for
 /// a component. Practically just a generational index, like `CompId` is.
 #[derive(Copy, Clone)]
 pub(crate) struct CompKey(CompId);
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub(crate) struct CompKey(u32);
 /// Generational ID of a component
 #[derive(Copy, Clone)]
 pub(crate) struct CompId {
     pub index: u32,
     pub generation: u32,
 impl CompKey {
     pub(crate) fn downgrade(&self) -> CompId {
         return CompId(self.0);
+    }
+}
 impl PartialEq for CompId {
     fn eq(&self, other: &Self) -> bool {
         return self.index.eq(&other.index);
 /// Generational ID of a component
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub struct CompId(u32);
 impl CompId {
     pub(crate) fn new_invalid() -> CompId {
         return CompId(u32::MAX);
+    }
     /// Upgrade component ID to component key. Unsafe because the caller needs
     /// to make sure that only one component key can exist at a time (to ensure
     /// a component can only be scheduled/executed by one thread).
     pub(crate) unsafe fn upgrade(&self) -> CompKey {
         return CompKey(self.0);
+    }
+}
 impl Eq for CompId {}
 /// In-runtime storage of a component
 pub(crate) struct RtComp {
 pub(crate) struct RuntimeComp {
     pub public: CompPublic,
     pub private: CompPrivate,
+}
 /// Should contain everything that is accessible in a thread-safe manner
 pub(crate) struct CompPublic {
     pub sleeping: AtomicBool,
     pub num_handles: AtomicU32, // modified upon creating/dropping `CompHandle` instances
+}
 /// Handle to public part of a component.
 pub(crate) struct CompHandle {
     target: *const CompPublic,
+}
 impl std::ops::Deref for CompHandle {
     type Target = CompPublic;
     fn deref(&self) -> &Self::Target {
         return unsafe{ &*self.target };
+    }
+}
 /// May contain non thread-safe fields. Accessed only by the scheduler which
 /// will temporarily "own" the component.
 pub(crate) struct CompPrivate {
     pub code: CompPDL,
     pub ctx: CompCtx,
+}
 // -----------------------------------------------------------------------------
 // Runtime
 // -----------------------------------------------------------------------------
 type RuntimeHandle = Arc<Runtime>;
+pub type RuntimeHandle = Arc<Runtime>;
 /// Memory that is maintained by "the runtime". In practice it is maintained by
 /// multiple schedulers, and this serves as the common interface to that memory.
 pub struct Runtime {
     pub protocol: ProtocolDescription,
     components: ComponentStore<RuntimeComp>,
     work_queue: Mutex<VecDeque<CompKey>>,
     work_condvar: Condvar,
     active_elements: AtomicU32, // active components and APIs (i.e. component creators)
+}
 impl Runtime {
     pub fn new(num_threads: u32, protocol_description: ProtocolDescription) -> Runtime {
         assert!(num_threads > 0, "need a thread to perform work");
         return Runtime{
             protocol: protocol_description,
             components: ComponentStore::new(128),
             work_queue: Mutex::new(VecDeque::with_capacity(128)),
             work_condvar: Condvar::new(),
             active_elements: AtomicU32::new(0),
         };
+    }
+}
 // -----------------------------------------------------------------------------
 // Runtime containers
 // -----------------------------------------------------------------------------
 /// Component storage. Note that it shouldn't be polymorphic, but making it so
 /// allows us to test it more easily. The container is essentially a
 /// thread-safe freelist. The list always contains *all* free entries in the
 /// storage array.
 ///
 /// The freelist itself is implemented using a thread-safe ringbuffer. But there
 /// are some very important properties we exploit in this specific
 /// implementation of a ringbuffer. Note that writing to the ringbuffer (i.e.
 /// adding to the freelist) corresponds to destroying a component, and reading
 /// from the ringbuffer corresponds to creating a component. The aforementioned
 /// properties are: one can never write more to the ringbuffer than has been
 /// read from it (i.e. destroying more components than are created), we may
 /// safely assume that when the `CompStore` is dropped that no thread can access
 /// it (because they've all been shut down). This simplifies deallocation code.
 ///
 /// Internally each individual instance of `T` will be (de)allocated. So we will
 /// not store an array of `T`, but an array of `*T`. This keeps the storage of
 /// `T` pointer-stable (as is required for the schedulers actually running the
 /// components, because they'll fetch a component and then continue running it
 /// while this component storage might get reallocated).
 ///
 /// Note that there is still some unsafety here that is kept in check by the
 /// owner of this `CompStore`: the `CompId` and `CompKey` system ensures that
 /// only one mutable reference will ever be obtained, and potentially multiple
 /// immutable references. But in practice the `&mut T` will be used to access
 /// so-called "public" fields immutably, and "private" fields mutable. While the
 /// `&T` will only be used to access the "public" fields immutably.
 struct CompStore<T: Sized> {
     freelist: *mut u32,
     data: *mut *mut T,
     count: usize,
     mask: usize,
     byte_size: usize, // used for dealloc
     write_head: AtomicUsize,
     limit_head: AtomicUsize,
     read_head: AtomicUsize,
+}
 const fn compute_realloc_flag() -> usize {
     match size_of::<usize>() {
 => return 1 << 31, // 32-bit system
 => return 1 << 63, // 64-bit system
         _ => panic!("unexpected byte size for 'usize'")
+    }
+}
 impl<T: Sized> CompStore<T> {
     const REALLOC_FLAG: usize = compute_realloc_flag();
     fn new(initial_count: usize) -> Self {
         // Allocate data
         debug_assert!(size_of::<T>() > 0); // No ZST during testing (and definitely not in production)
         let (freelist, data, byte_size) = Self::alloc_buffer(initial_count);
         unsafe {
             // Init the freelist to all of the indices in the array of data
             let mut target = freelist;
             for idx in 0..initial_count as u32 {
                 *target = idx;
                 target += 1;
+            }
     // Scheduling and retrieving work
             // And init the data such that they're all NULL pointers
             std::ptr::write_bytes(data, 0, initial_count);
     pub(crate) fn take_work(&self) -> Option<CompKey> {
         let mut lock = self.work_queue.lock().unwrap();
         while lock.is_empty() && self.active_elements.load(Ordering::Acquire) != 0 {
             lock = self.work_condvar.wait(lock).unwrap();
+        }
         return CompStore{
             freelist, data,
             count: initial_count,
             mask: initial_count - 1,
             byte_size,
             write_head: AtomicUsize::new(initial_count),
             limit_head: AtomicUsize::new(initial_count),
             read_head: AtomicUsize::new(0),
         };
         return lock.pop_front();
+    }
     fn get_index_from_freelist(&self) -> u32 {
         let compare_mask = (self.count * 2) - 1;
         let mut read_index = self.read_head.load(Ordering::Acquire); // read index first
         'try_loop: loop {
             let limit_index = self.limit_head.load(Ordering::Acquire); // limit index second
             // By definition we always have `read_index <= limit_index` (if we would
             // have an infinite buffer, in reality we will wrap).
             if (read_index & compare_mask) == (limit_index & compare_mask) {
                 // We need to create a bigger buffer. Note that no reader can
                 // *ever* set the read index to beyond the limit index, and it
                 // is currently equal. So we're certain that there is no other
                 // reader currently updating the read_head.
                 //
                 // To test if we are supposed to resize the backing buffer we
                 // try set the REALLOC_FLAG on the limit index. Note that the
                 // stored indices are always in the range [0, 2*count). So if
                 // we add REALLOC_FLAG to the limit index, then the masked
                 // condition above still holds! Other potential readers will end
                 // up here and are allowed to wait until we resized the backing
                 // container.
                 //
                 // Furthermore, setting the limit index to this high value also
                 // notifies the writer that any of it writes should be tried
                 // again, as they're writing to a buffer that is going to get
                 // trashed.
                 todo!("finish reallocation code");
                 match self.limit_head.compare_exchange(limit_index, limit_index | Self::REALLOC_FLAG, Ordering::SeqCst, Ordering::Acquire) {
                     Ok(_) => {
                         // Limit index has changed, so we're now the ones that
                         // are supposed to resize the
+                    }
+                }
             } else {
                 // It seems we have space to read
                 let preemptive_read = unsafe { *self.freelist.add(read_index & self.mask) };
                 if let Err(new_read_index) = self.read_head.compare_exchange(read_index, (read_index + 1) & compare_mask, Ordering::SeqCst, Ordering::Acquire) {
                     // Failed to do the CAS, try again. We need to start at the
                     // start again because we might have had other readers that
                     // were successful, so at the very least, the preemptive
                     // read we did is no longer correct.
                     read_index = new_read_index;
                     continue 'try_loop;
+                }
                 // We now "own" the value at the read index
                 return preemptive_read;
+            }
+        }
     pub(crate) fn enqueue_work(&self, key: CompKey) {
         let mut lock = self.work_queue.lock().unwrap();
         lock.push_back(key);
         self.work_condvar.notify_one();
+    }
     fn put_back_index_into_freelist(&self, index: u32) {
         let mut compare_mask = (self.count * 2) - 1;
         let mut write_index = self.write_head.load(Ordering::Acquire);
         while let Err(new_write_index) = self.write_head.compare_exchange(write_index, (write_index + 1) & compare_mask, Ordering::SeqCst, Ordering::Acquire) {
             // Failed to do the CAS, try again
             write_index = new_write_index;
+        }
         'try_write_loop: loop {
             // We are now the only ones that can write at `write_index`. Try to
             // do so
             unsafe { *self.freelist.add(write_index & self.mask) = index; }
             // But we still need to move the limit head. Only succesful writers
             // may move it so we expect it to move from the `write_index` to
             // `write_index + 1`, but we might have to spin to achieve it.
             // Furthermore, the `limit_head` is used by the index-retrieval
             // function to indicate that a read is in progress.
             'commit_to_write_loop: loop {
                 match self.limit_head.compare_exchange(write_index, (write_index + 1) & compare_mask, Ordering::SeqCst, Ordering::Acquire) {
                     Ok(_) => break,
                     Err(new_value) => {
                         // Two options: the limit is not yet what we expect it
                         // to be. If so, just try again with the old values.
                         // But if it is very large (relatively) then this is the
                         // signal from the reader that the entire storage is
                         // being resized
                         if new_value & Self::REALLOC_FLAG != 0 {
                             // Someone is resizing, wait until that is no longer
                             // true.
                             while self.limit_head.load(Ordering::Acquire) & Self::REALLOC_FLAG != 0 {
                                 // still resizing
+                            }
                             // Not resizing anymore, try everything again, our
                             // old write has now become invalid. But our index
                             // hasn't! So we need to finish our write and our
                             // increment of the limit head
                             continue 'try_write_loop;
                         } else {
                             // Just try again
                             continue 'commit_to_write_loop;
+                        }
+                    }
     // Creating/destroying components
     pub(crate) fn create_pdl_component(&self, comp: CompPDL, initially_sleeping: bool) -> CompKey {
         let comp = RuntimeComp{
             public: CompPublic{
                 sleeping: AtomicBool::new(initially_sleeping),
                 num_handles: AtomicU32::new(1), // the component itself acts like a handle
             },
             private: CompPrivate{
                 code: comp,
                 ctx: CompCtx{
                     id: CompId(0),
                     ports: Vec::new(),
                     peers: Vec::new(),
                     messages: Vec::new(),
+                }
+            }
         };
             // We updated the limit head, so we're done :)
             return;
+        }
+    }
     /// Retrieves a `&T` from the store. This should be retrieved using `create`
     /// and not yet given back by calling `destroy`.
     fn get(&self, index: u32) -> &T {
         let index = self.components.create(comp);
+    }
     /// Same as `get`, but now returning a mutable `&mut T`. Make sure that you
     /// know what you're doing :)
     fn get_mut(&self, index: u32) -> &mut T {
         // TODO: just do a reserve_index followed by a consume_index or something
         self.components.get_mut(index).private.ctx.id = CompId(index);
         return CompKey(index);
+    }
     fn alloc_buffer(num: usize) -> (*mut u32, *mut *mut T, usize) {
         // Probably overkill considering the amount of memory that is needed to
         // exceed this number. But still: ensure `num` adheres to the
         // requirements needed for correct functioning of the store.
         assert!(
             num >= 8 && num <= u32::MAX as usize / 4 && num.is_power_of_two(),
             "invalid allocation count for CompStore buffer"
         );
         // Compute byte size of freelist (so we assume alignment of `u32`)
         let mut byte_size = num * size_of::<u32>();
         // Align to `*mut T`, then reserve space for all of the pointers
         byte_size = Self::align_to(byte_size, align_of::<*mut T>());
         let byte_offset_data = byte_size;
         byte_size += num * size_of::<T>;
         unsafe {
             // Allocate, then retrieve pointers to allocated regions
             let layout = Self::layout_for(byte_size);
             let memory = alloc(layout);
             let base_free: *mut u32 = transmute(memory);
             let base_data: *mut *mut T = transmute(memory.add(byte_offset_data));
             return (base_free, base_data, byte_size);
+        }
     pub(crate) fn get_component(&self, key: CompKey) -> &mut RuntimeComp {
         let component = self.components.get_mut(key.0);
         return component;
+    }
     fn dealloc_buffer(freelist: *mut u32, _data: *mut *mut T, byte_size: usize) {
         // Note: we only did one allocation, freelist is at the front
         let layout = Self::layout_for(byte_size);
         unsafe {
             let base: *mut u8 = transmute(freelist);
             dealloc(base, layout);
+        }
     pub(crate) fn get_component_public(&self, id: CompId) -> &CompPublic {
         let component = self.components.get(id.0);
         return &component.public;
+    }
     fn layout_for(byte_size: usize) -> Layout {
         debug_assert!(byte_size % size_of::<u32>() == 0);
         return unsafe{ Layout::from_size_align_unchecked(byte_size, align_of::<u32>()) };
     pub(crate) fn destroy_component(&self, key: CompKey) {
         self.components.destroy(key.0);
+    }
     fn align_to(offset: usize, alignment: usize) -> usize {
         debug_assert!(alignment.is_power_of_two());
         let mask = alignment - 1;
         return (offset + mask) & !mask;
+    }
+}
@@ \ No newline at end of file @@
     // Interacting with components
+}

src/runtime2/scheduler.rs

➞

Show inline comments

@@ new file 100644 @@
 use std::sync::atomic::Ordering;
 use super::component::*;
 use super::runtime::*;
 /// Data associated with a scheduler thread
 pub(crate) struct Scheduler {
     runtime: RuntimeHandle,
     scheduler_id: u32,
+}
 pub(crate) struct SchedulerCtx<'a> {
     pub runtime: &'a Runtime,
+}
 impl Scheduler {
     // public interface to thread
     pub fn new(runtime: RuntimeHandle, scheduler_id: u32) -> Self {
         return Scheduler{ runtime, scheduler_id }
+    }
     pub fn run(&mut self) {
         let scheduler_ctx = SchedulerCtx{ runtime: &*self.runtime };
         'run_loop: loop {
             // Wait until we have something to do (or need to quit)
             let comp_key = self.runtime.take_work();
             if comp_key.is_none() {
                 break 'run_loop;
+            }
             let comp_key = comp_key.unwrap();
             let comp_id = comp_key.downgrade();
             let component = self.runtime.get_component(comp_key);
             // Run the component until it no longer indicates that it needs to
             // be re-executed immediately.
             let mut new_scheduling = CompScheduling::Immediate;
             while let CompScheduling::Immediate = new_scheduling {
                 new_scheduling = component.private.code.run(&scheduler_ctx, &mut component.private.ctx).expect("TODO: Handle error");
+            }
             // Handle the new scheduling
             match new_scheduling {
                 CompScheduling::Immediate => unreachable!(),
                 CompScheduling::Requeue => { self.runtime.enqueue_work(comp_key); },
                 CompScheduling::Sleep => { self.mark_component_as_sleeping(comp_key, component); },
                 CompScheduling::Exit => { self.mark_component_as_exiting(comp_key, component); }
+            }
+        }
+    }
     // local utilities
     fn mark_component_as_sleeping(&self, key: CompKey, component: &mut RuntimeComp) {
         debug_assert_eq!(key.downgrade(), component.private.ctx.id); // make sure component matches key
         debug_assert_eq!(component.public.sleeping.load(Ordering::Acquire), false); // we're executing it, so it cannot be sleeping
         component.public.sleeping.store(true, Ordering::Release);
         todo!("check for messages");
+    }
     fn mark_component_as_exiting(&self, key: CompKey, component: &mut RuntimeComp) {
         todo!("do something")
+    }
+}
@@ \ No newline at end of file @@

src/runtime2/store/component.rs

➞

Show inline comments

@@ new file 100644 @@
 /*
  * Component Store
+ *
  * Concurrent datastructure for creating/destroying/retrieving components using
  * their ID. It is essentially a variation on a concurrent freelist. We store an
  * array of (potentially null) pointers to data. Indices into this array that
  * are unused (but may be left allocated) are in a freelist. So creating a new
  * bit of data involves taking an index from this freelist. Destruction involves
  * putting the index back.
+ *
  * This datastructure takes care of the threadsafe implementation of the
  * freelist and calling the data's destructor when needed. Note that it is not
  * completely safe (in Rust's sense of the word) because it is possible to
  * get more than one mutable reference to a piece of data. Likewise it is
  * possible to put back bogus indices into the freelist, which will destroy the
  * integrity of the datastructure.
+ *
  * Some underlying assumptions that led to this design (note that I haven't
  * actually checked these conditions or performed any real profiling, yet):
  *  - Resizing the freelist should be very rare. The datastructure should grow
  *    to some kind of maximum size and stay at that size.
  *  - Creation should (preferably) be faster than deletion of data. Reason being
  *    that creation implies we're creating a component that has code to be
  *    executed. Better to quickly be able to execute code than being able to
  *    quickly tear down finished components.
  *  - Retrieval is much more likely than creation/destruction.
+ *
  * Some obvious flaws with this implementation:
  *  - Because of the freelist implementation we will generally allocate all of
  *    the data pointers that are available (i.e. if we have a buffer of size
  *    64, but we generally use 33 elements, than we'll have 64 elements
  *    allocated), which might be wasteful at larger array sizes (which are
  *    always powers of two).
  *  - A lot of concurrent operations are not necessary: we may move some of the
  *    access to the global concurrent datastructure by an initial access to some
  *    kind of thread-local datastructure.
  */
 use std::mem::transmute;
 use std::alloc::{alloc, dealloc, Layout};
 use std::ptr;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use super::unfair_se_lock::{UnfairSeLock, UnfairSeLockSharedGuard};
 pub struct ComponentStore<T: Sized> {
     inner: UnfairSeLock<Inner<T>>,
     read_head: AtomicUsize,
     write_head: AtomicUsize,
     limit_head: AtomicUsize,
+}
 unsafe impl<T: Sized> Send for ComponentStore<T>{}
 unsafe impl<T: Sized> Sync for ComponentStore<T>{}
 struct Inner<T: Sized> {
     freelist: Vec<u32>,
     data: Vec<*mut T>,
     size: usize,
     compare_mask: usize,
     index_mask: usize,
+}
 type InnerRead<'a, T> = UnfairSeLockSharedGuard<'a, Inner<T>>;
 impl<T: Sized> ComponentStore<T> {
     pub fn new(initial_size: usize) -> Self {
         Self::assert_valid_size(initial_size);
         // Fill initial freelist and preallocate data array
         let mut initial_freelist = Vec::with_capacity(initial_size);
         for idx in 0..initial_size {
             initial_freelist.push(idx as u32)
+        }
         let mut initial_data = Vec::new();
         initial_data.resize(initial_size, ptr::null_mut());
         // Return initial store
         return Self{
             inner: UnfairSeLock::new(Inner{
                 freelist: initial_freelist,
                 data: initial_data,
                 size: initial_size,
                 compare_mask: 2*initial_size - 1,
                 index_mask: initial_size - 1,
             }),
             read_head: AtomicUsize::new(0),
             write_head: AtomicUsize::new(initial_size),
             limit_head: AtomicUsize::new(initial_size),
         };
+    }
     /// Creates a new element initialized to the provided `value`. This returns
     /// the index at which the element can be retrieved.
     pub fn create(&self, value: T) -> u32 {
         let lock = self.inner.lock_shared();
         let (lock, index) = self.pop_freelist_index(lock);
         self.initialize_at_index(lock, index, value);
         return index;
+    }
     /// Destroys an element at the provided `index`. The caller must make sure
     /// that it does not use any previously received references to the data at
     /// this index, and that no more calls to `get` are performed using this
     /// index. This is allowed again if the index has been reacquired using
     /// `create`.
     pub fn destroy(&self, index: u32) {
         let lock = self.inner.lock_shared();
         self.destruct_at_index(&lock, index);
         self.push_freelist_index(&lock, index);
+    }
     /// Retrieves an element by reference
     pub fn get(&self, index: u32) -> &T {
         let lock = self.inner.lock_shared();
         let value = lock.data[index as usize];
         unsafe {
             debug_assert!(!value.is_null());
             return &*value;
+        }
+    }
     /// Retrieves an element by mutable reference. The caller should ensure that
     /// use of that mutability is thread-safe
     pub fn get_mut(&self, index: u32) -> &mut T {
         let lock = self.inner.lock_shared();
         let value = lock.data[index as usize];
         unsafe {
             debug_assert!(!value.is_null());
             return &mut *value;
+        }
+    }
     #[inline]
     fn pop_freelist_index<'a>(&'a self, mut read_lock: InnerRead<'a, T>) -> (InnerRead<'a, T>, u32) {
         'attempt_read: loop {
             // Load indices and check for reallocation condition
             let current_size = read_lock.size;
             let mut read_index = self.read_head.load(Ordering::Relaxed);
             let limit_index = self.limit_head.load(Ordering::Acquire);
             if read_index == limit_index {
                 read_lock = self.reallocate(current_size, read_lock);
                 continue 'attempt_read;
+            }
             loop {
                 let preemptive_read = read_lock.freelist[read_index & read_lock.index_mask];
                 if let Err(actual_read_index) = self.read_head.compare_exchange(
                     read_index, (read_index + 1) & read_lock.compare_mask,
                     Ordering::AcqRel, Ordering::Acquire
                 ) {
                     // We need to try again
                     read_index = actual_read_index;
                     continue 'attempt_read;
+                }
                 // If here then we performed the read
                 return (read_lock, preemptive_read);
+            }
+        }
+    }
     #[inline]
     fn initialize_at_index(&self, read_lock: InnerRead<T>, index: u32, value: T) {
         let mut target_ptr = read_lock.data[index as usize];
         unsafe {
             if target_ptr.is_null() {
                 let layout = Layout::for_value(&value);
                 target_ptr = std::alloc::alloc(layout).cast();
                 let rewrite: *mut *mut T = transmute(read_lock.data.as_ptr());
                 *rewrite.add(index as usize) = target_ptr;
+            }
             std::ptr::write(target_ptr, value);
+        }
+    }
     #[inline]
     fn push_freelist_index(&self, read_lock: &InnerRead<T>, index_to_put_back: u32) {
         // Acquire an index in the freelist to which we can write
         let mut cur_write_index = self.write_head.load(Ordering::Relaxed);
         let mut new_write_index = (cur_write_index + 1) & read_lock.compare_mask;
         while let Err(actual_write_index) = self.write_head.compare_exchange(
             cur_write_index, new_write_index,
             Ordering::AcqRel, Ordering::Acquire
         ) {
             cur_write_index = actual_write_index;
             new_write_index = (cur_write_index + 1) & read_lock.compare_mask;
+        }
         // We own the data at the index, write to it and notify reader through
         // limit_head that it can be read from. Note that we cheat around the
         // rust mutability system here :)
         unsafe {
             let target: *mut u32 = transmute(read_lock.freelist.as_ptr());
             *(target.add(cur_write_index & read_lock.index_mask)) = index_to_put_back;
+        }
         // Essentially spinlocking, relaxed failure ordering because the logic
         // is that a write first moves the `write_head`, then the `limit_head`.
         while let Err(_) = self.limit_head.compare_exchange(
             cur_write_index, new_write_index,
             Ordering::AcqRel, Ordering::Relaxed
         ) {};
+    }
     #[inline]
     fn destruct_at_index(&self, read_lock: &InnerRead<T>, index: u32) {
         let target_ptr = read_lock.data[index as usize];
         unsafe{ ptr::drop_in_place(target_ptr); }
+    }
     fn reallocate(&self, old_size: usize, inner: InnerRead<T>) -> InnerRead<T> {
         drop(inner);
+        {
             // After dropping read lock, acquire write lock
             let mut lock = self.inner.lock_exclusive();
             if old_size == lock.size {
                 // We are the thread that is supposed to reallocate
                 let new_size = old_size * 2;
                 Self::assert_valid_size(new_size);
                 // Note that the atomic indices are in the range [0, new_size)
                 // already, so we need to be careful
                 let new_index_mask = new_size - 1;
                 let new_compare_mask = (2 * new_size) - 1;
                 lock.data.resize(new_size, ptr::null_mut());
                 lock.freelist.resize(new_size, 0);
                 for idx in 0..old_size {
                     lock.freelist[old_size + idx] = lock.freelist[idx];
+                }
                 // We need to fill the freelist with the indices of all of the
                 // new elements that we have just created.
                 debug_assert_eq!(self.limit_head.load(Ordering::SeqCst), self.write_head.load(Ordering::SeqCst));
                 let old_read_index = self.read_head.load(Ordering::SeqCst);
                 let old_write_index = self.write_head.load(Ordering::SeqCst);
                 if old_read_index > old_write_index {
                     // Read index wraps, so keep it as-is and fill
                     let new_read_index = old_read_index + old_size;
                     for index in 0..old_size {
                         let target_idx = (new_read_index + index) & new_index_mask;
                         lock.freelist[target_idx] = (old_size + index) as u32;
+                    }
                     self.read_head.store(new_read_index, Ordering::SeqCst);
                     debug_assert!(new_read_index < 2*new_size);
                     debug_assert!(old_write_index.wrapping_sub(new_read_index) & new_compare_mask <= new_size);
                 } else {
                     // No wrapping, so increment write index
                     let new_write_index = old_write_index + old_size;
                     for index in 0..old_size {
                         let target_idx = (old_write_index + index) & new_index_mask;
                         lock.freelist[target_idx] = (old_size + index) as u32;
+                    }
                     // Update write/limit heads
                     self.write_head.store(new_write_index, Ordering::SeqCst);
                     self.limit_head.store(new_write_index, Ordering::SeqCst);
                     debug_assert!(new_write_index < 2*new_size);
                     debug_assert!(new_write_index.wrapping_sub(old_read_index) & new_compare_mask <= new_size);
+                }
                 // Update sizes and masks
                 lock.size = new_size;
                 lock.compare_mask = new_compare_mask;
                 lock.index_mask = new_index_mask;
             } // else: someone else allocated, so we don't have to
+        }
         // We've dropped the write lock, acquire the read lock again
         return self.inner.lock_shared();
+    }
     #[inline]
     fn assert_valid_size(size: usize) {
         // Condition the size needs to adhere to. Some are a bit excessive, but
         // we don't hit this check very often
         assert!(
             size.is_power_of_two() &&
                 size >= 4 &&
                 size <= usize::MAX / 2 &&
                 size <= u32::MAX as usize
         );
+    }
+}
 impl<T: Sized> Drop for ComponentStore<T> {
     fn drop(&mut self) {
         let value_layout = Layout::from_size_align(
             std::mem::size_of::<T>(), std::mem::align_of::<T>()
         ).unwrap();
         // Note that if the indices exist in the freelist then the destructor
         // has already been called. So handle them first
         let mut lock = self.inner.lock_exclusive();
         let read_index = self.read_head.load(Ordering::Acquire);
         let write_index = self.write_head.load(Ordering::Acquire);
         debug_assert_eq!(write_index, self.limit_head.load(Ordering::Acquire));
         let mut index = read_index;
         while index != write_index {
             let dealloc_index = lock.freelist[index & lock.index_mask] as usize;
             let target_ptr = lock.data[dealloc_index];
             unsafe {
                 dealloc(target_ptr.cast(), value_layout);
                 lock.data[dealloc_index] = ptr::null_mut();
+            }
             index += 1;
             index &= lock.compare_mask;
+        }
         // With all of those set to null, we'll just iterate through all
         // pointers and destruct+deallocate the ones not set to null yet
         for target_ptr in lock.data.iter().copied() {
             if !target_ptr.is_null() {
                 unsafe {
                     ptr::drop_in_place(target_ptr);
                     dealloc(target_ptr.cast(), value_layout);
+                }
+            }
+        }
+    }
+}
 #[cfg(test)]
 mod tests {
     use super::*;
     use rand::prelude::*;
     use rand_pcg::Pcg32;
     use std::sync::Arc;
     use std::sync::atomic::{AtomicU64, Ordering};
     pub struct Resource {
         dtor: Arc<AtomicU64>,
         val: u64,
+    }
     impl Resource {
         fn new(ctor: Arc<AtomicU64>, dtor: Arc<AtomicU64>, val: u64) -> Self {
             ctor.fetch_add(1, Ordering::SeqCst);
             return Self{ dtor, val };
+        }
+    }
     impl Drop for Resource {
         fn drop(&mut self) {
             self.dtor.fetch_add(1, Ordering::SeqCst);
+        }
+    }
     fn seeds() -> Vec<[u8;16]> {
         return vec![
             [241, 47, 70, 87, 240, 246, 20, 173, 219, 143, 74, 23, 158, 58, 205, 172],
             [178, 112, 230, 205, 230, 178, 2, 90, 162, 218, 49, 196, 224, 222, 208, 43],
             [245, 42, 35, 167, 153, 205, 221, 144, 200, 253, 144, 117, 176, 231, 17, 70],
             [143, 39, 177, 216, 124, 96, 225, 39, 30, 82, 239, 193, 133, 58, 255, 193],
             [25, 105, 10, 52, 161, 212, 190, 112, 178, 193, 68, 249, 167, 153, 172, 144],
+        ]
+    }
     #[test]
     fn test_ctor_dtor_simple_unthreaded() {
         const NUM_ROUNDS: usize = 5;
         const NUM_ELEMENTS: usize = 1024;
         let store = ComponentStore::new(32);
         let ctor_counter = Arc::new(AtomicU64::new(0));
         let dtor_counter = Arc::new(AtomicU64::new(0));
         let mut indices = Vec::with_capacity(NUM_ELEMENTS);
         for _round_index in 0..NUM_ROUNDS {
             // Creation round
             for value in 0..NUM_ELEMENTS {
                 let new_resource = Resource::new(ctor_counter.clone(), dtor_counter.clone(), value as u64);
                 let new_index = store.create(new_resource);
                 indices.push(new_index);
+            }
             // Checking round
             for el_index in indices.iter().copied() {
                 let element = store.get(el_index);
                 assert_eq!(element.val, el_index as u64);
+            }
             // Destruction round
             for el_index in indices.iter().copied() {
                 store.destroy(el_index);
+            }
             indices.clear();
+        }
         let num_ctor_calls = ctor_counter.load(Ordering::Acquire);
         let num_dtor_calls = dtor_counter.load(Ordering::Acquire);
         assert_eq!(num_ctor_calls, num_dtor_calls);
         assert_eq!(num_ctor_calls, (NUM_ROUNDS * NUM_ELEMENTS) as u64);
+    }
     #[test]
     fn test_ctor_dtor_simple_threaded() {
         const MAX_SIZE: usize = 1024;
         const NUM_THREADS: usize = 4;
         const NUM_PER_THREAD: usize = MAX_SIZE / NUM_THREADS;
         const NUM_ROUNDS: usize = 4;
         assert!(MAX_SIZE % NUM_THREADS == 0);
         let store = Arc::new(ComponentStore::new(16));
         let ctor_counter = Arc::new(AtomicU64::new(0));
         let dtor_counter = Arc::new(AtomicU64::new(0));
         let mut threads = Vec::with_capacity(NUM_THREADS);
         for thread_index in 0..NUM_THREADS {
             // Setup local clones to move into the thread
             let store = store.clone();
             let first_index = thread_index * NUM_PER_THREAD;
             let last_index = (thread_index + 1) * NUM_PER_THREAD;
             let ctor_counter = ctor_counter.clone();
             let dtor_counter = dtor_counter.clone();
             let handle = std::thread::spawn(move || {
                 let mut indices = Vec::with_capacity(last_index - first_index);
                 for _round_index in 0..NUM_ROUNDS {
                     // Creation round
                     for value in first_index..last_index {
                         let el_index = store.create(Resource::new(ctor_counter.clone(), dtor_counter.clone(), value as u64));
                         indices.push(el_index);
+                    }
                     // Checking round
                     for (value_offset, el_index) in indices.iter().copied().enumerate() {
                         let element = store.get(el_index);
                         assert_eq!(element.val, (first_index + value_offset) as u64);
+                    }
                     // Destruction round
                     for el_index in indices.iter().copied() {
                         store.destroy(el_index);
+                    }
                     indices.clear();
+                }
             });
             threads.push(handle);
+        }
         for thread in threads {
             thread.join().expect("clean exit");
+        }
         let num_ctor_calls = ctor_counter.load(Ordering::Acquire);
         let num_dtor_calls = dtor_counter.load(Ordering::Acquire);
         assert_eq!(num_ctor_calls, num_dtor_calls);
         assert_eq!(num_ctor_calls, (NUM_ROUNDS * MAX_SIZE) as u64);
+    }
     #[test]
     fn test_ctor_dtor_random_threaded() {
         const NUM_ROUNDS: usize = 4;
         const NUM_THREADS: usize = 4;
         const NUM_OPERATIONS: usize = 1024;
         const NUM_OPS_PER_THREAD: usize = NUM_OPERATIONS / NUM_THREADS;
         const NUM_OPS_PER_ROUND: usize = NUM_OPS_PER_THREAD / NUM_ROUNDS;
         const NUM_STORED_PER_THREAD: usize = 32;
         assert!(NUM_OPERATIONS % NUM_THREADS == 0);
         assert!(NUM_OPS_PER_THREAD / 2 > NUM_STORED_PER_THREAD);
         let seeds = seeds();
         for seed_index in 0..seeds.len() {
             // Setup store, counters and threads
             let store = Arc::new(ComponentStore::new(16));
             let ctor_counter = Arc::new(AtomicU64::new(0));
             let dtor_counter = Arc::new(AtomicU64::new(0));
             let mut threads = Vec::with_capacity(NUM_THREADS);
             for thread_index in 0..NUM_THREADS {
                 // Setup local clones to move into the thread
                 let store = store.clone();
                 let ctor_counter = ctor_counter.clone();
                 let dtor_counter = dtor_counter.clone();
                 // Setup local rng
                 let mut seed = seeds[seed_index];
                 for seed_val_idx in 0..16 {
                     seed[seed_val_idx] ^= thread_index as u8; // blegh
+                }
                 let mut rng = Pcg32::from_seed(seed);
                 let handle = std::thread::spawn(move || {
                     let mut stored = Vec::with_capacity(NUM_STORED_PER_THREAD);
                     for _round_index in 0..NUM_ROUNDS {
                         // Modify store elements in the store randomly, for some
                         // silly definition of random
                         for _op_index in 0..NUM_OPS_PER_ROUND {
                             // Perform a single operation, depending on current
                             // size of the number of values owned by this thread
                             let new_value = rng.next_u64();
                             let should_create = rng.next_u32() % 2 == 0;
                             let is_empty = stored.is_empty();
                             let is_full = stored.len() == NUM_STORED_PER_THREAD;
                             if is_empty || (!is_full && should_create) {
                                 // Must create
                                 let el_index = store.create(Resource::new(
                                     ctor_counter.clone(), dtor_counter.clone(), new_value
                                 ));
                                 stored.push((el_index, new_value));
                             } else {
                                 // Must destroy
                                 let stored_index = new_value as usize % stored.len();
                                 let (el_index, el_value) = stored.remove(stored_index);
                                 store.destroy(el_index);
+                            }
+                        }
                         // Checking if the values we own still make sense
                         for (el_index, value) in stored.iter().copied() {
                             let gotten = store.get(el_index);
                             assert_eq!(value, gotten.val, "failed at thread {} value {}", thread_index, el_index);
+                        }
+                    }
                     return stored.len(); // return number of remaining elements
                 });
                 threads.push(handle);
+            }
             // Done with the current round
             let mut total_left_allocated = 0;
             for thread in threads {
                 let num_still_stored = thread.join().unwrap();
                 total_left_allocated += num_still_stored as u64;
+            }
             // Before store is dropped
             let num_ctor_calls = ctor_counter.load(Ordering::Acquire);
             let num_dtor_calls = dtor_counter.load(Ordering::Acquire);
             assert_eq!(num_ctor_calls - total_left_allocated, num_dtor_calls);
             // After store is dropped
             drop(store);
             let num_dtor_calls = dtor_counter.load(Ordering::Acquire);
             assert_eq!(num_ctor_calls, num_dtor_calls);
+        }
+    }
+}
@@ \ No newline at end of file @@

src/runtime2/store/mod.rs

➞

Show inline comments

@@ new file 100644 @@
 pub mod component;
 pub mod unfair_se_lock;
 pub(crate) use component::ComponentStore;

src/runtime2/store/unfair_se_lock.rs

➞

Show inline comments

@@ new file 100644 @@
 use std::cell::UnsafeCell;
 use std::sync::atomic::{AtomicU32, Ordering};
 /// An unfair shared/exclusive lock. One may quickly describe this to be an
 /// unfair RwLock where a thread that wishes to write will get to write as fast
 /// as possible (i.e. waiting for readers to finish), but others writers in line
 /// may have to wait for another round of readers acquiring the lock.
 ///
 /// However, this is NOT a read/write lock. It is a shared/exclusive lock. It is
 /// used in concurrent datastructures (implemented with atomics), so particular
 /// kinds of writing may still occur by the threads holding a shared lock. In
 /// that case the programmer must make sure that these writes are coordinated
 /// in a thread-safe manner.
 ///
 /// It was designed with resizable (ring)buffers in mind: most often you have
 /// the standard atomic pointers/indices moving around in the ringbuffer. But
 /// when the buffer needs to be resized you need to be sure that no-one is
 /// reading/writing the wrong/old/deallocated buffer pointer. Hence the
 /// shared/exclusive terminology.
 ///
 /// For this reason the `UnfairSeLock` was written assuming that exclusive locks
 /// are only held sometime: shared locks are obtained most of the time.
 // Note: preliminary benchmark batches shows this is ~2x faster than a RwLock
 // when under some contention.
 pub struct UnfairSeLock<T> {
     // Uses 31 bits to track number of shared locks, and the high bit is set if
     // an exclusive lock is supposed to be held. 31 bits is more than sufficient
     // because in this project shared locks will be held by individual threads.
     shared: AtomicU32,
     cell: UnsafeCell<T>,
+}
 // Exclusive bit is set in the atomic value when a thread wishes to hold an
 // exclusive lock.
 const EXCLUSIVE_BIT: u32 = 1 << 31;
 impl<T> UnfairSeLock<T> {
     pub fn new(value: T) -> Self {
         return Self{
             shared: AtomicU32::new(0),
             cell: UnsafeCell::new(value),
+        }
+    }
     /// Get shared access to the underlying data.
     #[must_use]
     pub fn lock_shared(&self) -> UnfairSeLockSharedGuard<T> {
         let mut shared = self.shared.load(Ordering::Relaxed);
         loop {
             if shared & EXCLUSIVE_BIT != 0 {
                 shared = self.wait_until_not_exclusive(shared);
+            }
             // Spinlock until we've incremented. If we fail we need to check the
             // exclusive bit again.
             let new_shared = shared + 1;
             match self.shared.compare_exchange(shared, new_shared, Ordering::AcqRel, Ordering::Acquire) {
                 Ok(_) => return UnfairSeLockSharedGuard::new(self, new_shared),
                 Err(actual_value) => { shared = actual_value; },
+            }
+        }
+    }
     /// Get exclusive access to the underlying data.
     #[must_use]
     pub fn lock_exclusive(&self) -> UnfairSeLockExclusiveGuard<T> {
         let mut shared = self.shared.load(Ordering::Relaxed);
         loop {
             if shared & EXCLUSIVE_BIT != 0 {
                 shared = self.wait_until_not_exclusive(shared);
+            }
             // We want to set the write bit
             let new_shared = shared | EXCLUSIVE_BIT;
             match self.shared.compare_exchange(shared, new_shared, Ordering::AcqRel, Ordering::Acquire) {
                 Ok(_) => {
                     // We've acquired the write lock, but we still might have
                     // to wait until the reader count is at 0.
                     shared = new_shared;
                     if shared != EXCLUSIVE_BIT {
                         shared = self.wait_until_not_shared(shared);
+                    }
                     return UnfairSeLockExclusiveGuard::new(self);
                 },
                 Err(actual_value) => { shared = actual_value; }
+            }
+        }
+    }
     fn wait_until_not_exclusive(&self, mut shared: u32) -> u32 {
         // Assume this is only called when the EXCLUSIVE_BIT is set
         debug_assert_eq!(shared & EXCLUSIVE_BIT, EXCLUSIVE_BIT);
         loop {
             // So spin until no longer held
             shared = self.shared.load(Ordering::Acquire);
             if shared & EXCLUSIVE_BIT == 0 {
                 return shared;
+            }
+        }
+    }
     #[inline]
     fn wait_until_not_shared(&self, mut shared: u32) -> u32 {
         // This is only called when someone has signaled the exclusive bit, but
         // there are still threads holding the shared lock.
         loop {
             debug_assert_eq!(shared & EXCLUSIVE_BIT, EXCLUSIVE_BIT);
             if shared == EXCLUSIVE_BIT {
                 // shared count is 0
                 return shared;
+            }
             shared = self.shared.load(Ordering::Acquire);
+        }
+    }
+}
 /// A guard signifying that the owner has shared access to the underlying
 /// `UnfairSeLock`.
 pub struct UnfairSeLockSharedGuard<'a, T> {
     lock: &'a UnfairSeLock<T>,
     initial_value: u32,
+}
 impl<'a, T> UnfairSeLockSharedGuard<'a, T> {
     fn new(lock: &'a UnfairSeLock<T>, initial_value: u32) -> Self {
         return Self{ lock, initial_value };
+    }
     /// Force retrieval of the underlying type `T` in the mutable sense. Note
     /// that the caller is now responsible for ensuring that concurrent mutable
     /// access takes place in a correct fashion.
     #[inline]
     pub unsafe fn get_mut(&self) -> &mut T {
         return unsafe{ &mut *self.lock.cell.get() };
+    }
+}
 impl<'a, T> Drop for UnfairSeLockSharedGuard<'a, T> {
     fn drop(&mut self) {
         // Spinlock until we've decremented the number of shared locks.
         let mut value = self.initial_value;
         while let Err(actual_value) = self.lock.shared.compare_exchange_weak(
             value, value - 1, Ordering::AcqRel, Ordering::Acquire
         ) {
             value = actual_value;
+        }
+    }
+}
 impl<'a, T> std::ops::Deref for UnfairSeLockSharedGuard<'a, T> {
     type Target = T;
     fn deref(&self) -> &Self::Target {
         return unsafe{ &*self.lock.cell.get() };
+    }
+}
 /// A guard signifying that the owner has exclusive access to the underlying
 /// `UnfairSeLock`.
 pub struct UnfairSeLockExclusiveGuard<'a, T> {
     lock: &'a UnfairSeLock<T>,
+}
 impl<'a, T> UnfairSeLockExclusiveGuard<'a, T> {
     fn new(lock: &'a UnfairSeLock<T>) -> Self {
         return Self{ lock };
+    }
+}
 impl<'a, T> Drop for UnfairSeLockExclusiveGuard<'a, T> {
     fn drop(&mut self) {
         // We have the exclusive bit set, and this type was constructed when
         // the number of shared locks was at 0, we can safely store a `0` into
         // the atomic
         debug_assert_eq!(self.lock.shared.load(Ordering::Relaxed), EXCLUSIVE_BIT); // relaxed because we acquired it before
         self.lock.shared.store(0, Ordering::Release);
+    }
+}
 impl<'a, T> std::ops::Deref for UnfairSeLockExclusiveGuard<'a, T> {
     type Target = T;
     fn deref(&self) -> &Self::Target {
         return unsafe{ &*self.lock.cell.get() };
+    }
+}
 impl<'a, T> std::ops::DerefMut for UnfairSeLockExclusiveGuard<'a, T> {
     fn deref_mut(&mut self) -> &mut Self::Target {
         return unsafe{ &mut *self.lock.cell.get() };
+    }
+}
@@ \ No newline at end of file @@

0 comments (0 inline, 0 general)