Global variable dependency initialization ordering

Fuck graph theory

9 files changed, 503 insertions, 150 deletions

diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 5d0fc5ed3..ca1118a30 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -102,7 +102,7 @@ void check_init_variables(Checker *c, Entity **lhs, isize lhs_count, Array<AstNo
 	// an extra allocation
 	Array<Operand> operands = {};
 	array_init(&operands, c->tmp_allocator, 2*lhs_count);
-	check_unpack_arguments(c, lhs_count, &operands, inits, true);
+	check_unpack_arguments(c, lhs, lhs_count, &operands, inits, true);
 
 	isize rhs_count = operands.count;
 	for_array(i, operands) {
@@ -113,7 +113,13 @@ void check_init_variables(Checker *c, Entity **lhs, isize lhs_count, Array<AstNo
 
 	isize max = gb_min(lhs_count, rhs_count);
 	for (isize i = 0; i < max; i++) {
-		check_init_variable(c, lhs[i], &operands[i], context_name);
+		Entity *e = lhs[i];
+		DeclInfo *d = decl_info_of_entity(&c->info, e);
+		Operand *o = &operands[i];
+		check_init_variable(c, e, o, context_name);
+		if (d != nullptr) {
+			d->init_expr = o->expr;
+		}
 	}
 	if (rhs_count > 0 && lhs_count != rhs_count) {
 		error(lhs[0]->token, "Assignment count mismatch `%td` = `%td`", lhs_count, rhs_count);
@@ -550,7 +556,7 @@ void check_proc_decl(Checker *c, Entity *e, DeclInfo *d) {
 	}
 }
 
-void check_var_decl(Checker *c, Entity *e, Entity **entities, isize entity_count, AstNode *type_expr, AstNode *init_expr) {
+void check_var_decl(Checker *c, Entity *e, Entity **entities, isize entity_count, AstNode *type_expr, Array<AstNode *> init_expr_list) {
 	GB_ASSERT(e->type == nullptr);
 	GB_ASSERT(e->kind == Entity_Variable);
 
@@ -581,7 +587,7 @@ void check_var_decl(Checker *c, Entity *e, Entity **entities, isize entity_count
 
 
 	if (e->Variable.is_foreign) {
-		if (init_expr != nullptr) {
+		if (init_expr_list.count > 0) {
 			error(e->token, "A foreign variable declaration cannot have a default value");
 		}
 		init_entity_foreign_library(c, e);
@@ -606,31 +612,20 @@ void check_var_decl(Checker *c, Entity *e, Entity **entities, isize entity_count
 		}
 	}
 
-	if (init_expr == nullptr) {
+	if (init_expr_list.count == 0) {
 		if (type_expr == nullptr) {
 			e->type = t_invalid;
 		}
 		return;
 	}
 
-	if (entities == nullptr || entity_count == 1) {
-		GB_ASSERT(entities == nullptr || entities[0] == e);
-		Operand operand = {};
-		check_expr(c, &operand, init_expr);
-		check_init_variable(c, e, &operand, context_name);
-	}
-
 	if (type_expr != nullptr) {
 		for (isize i = 0; i < entity_count; i++) {
 			entities[i]->type = e->type;
 		}
 	}
 
-
-	Array<AstNode *> inits;
-	array_init(&inits, c->allocator, 1);
-	array_add(&inits, init_expr);
-	check_init_variables(c, entities, entity_count, inits, context_name);
+	check_init_variables(c, entities, entity_count, init_expr_list, context_name);
 }
 
 void check_entity_decl(Checker *c, Entity *e, DeclInfo *d, Type *named_type) {
@@ -657,7 +652,7 @@ void check_entity_decl(Checker *c, Entity *e, DeclInfo *d, Type *named_type) {
 
 	switch (e->kind) {
 	case Entity_Variable:
-		check_var_decl(c, e, d->entities, d->entity_count, d->type_expr, d->init_expr);
+		check_var_decl(c, e, d->entities, d->entity_count, d->type_expr, d->init_expr_list);
 		break;
 	case Entity_Constant:
 		check_const_decl(c, e, d->type_expr, d->init_expr, named_type);
@@ -757,9 +752,8 @@ void check_proc_body(Checker *c, Token token, DeclInfo *decl, Type *type, AstNod
 	if (decl->parent != nullptr) {
 		// NOTE(bill): Add the dependencies from the procedure literal (lambda)
 		for_array(i, decl->deps.entries) {
-			HashKey key = decl->deps.entries[i].key;
-			Entity *e = cast(Entity *)key.ptr;
-			map_set(&decl->parent->deps, key, true);
+			Entity *e = decl->deps.entries[i].ptr;
+			ptr_set_add(&decl->parent->deps, e);
 		}
 	}
 }
diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 0519aad4f..99ea66450 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -5968,19 +5968,44 @@ bool check_builtin_procedure(Checker *c, Operand *operand, AstNode *call, i32 id
 }
 
 
+isize add_dependencies_from_unpacking(Checker *c, Entity **lhs, isize lhs_count, isize tuple_index, isize tuple_count) {
+	if (lhs != nullptr) {
+		for (isize j = 0; tuple_index < lhs_count && j < tuple_count; j++) {
+			Entity *e = lhs[tuple_index + j];
+			DeclInfo *decl = decl_info_of_entity(&c->info, e);
+			if (decl != nullptr) {
+				c->context.decl = decl; // will be reset by the `defer` any way
+				for_array(k, decl->deps.entries) {
+					Entity *dep = decl->deps.entries[k].ptr;
+					add_declaration_dependency(c, dep); // TODO(bill): Should this be here?
+				}
+			}
+		}
+	}
+	return tuple_count;
+}
 
 
-
-bool check_unpack_arguments(Checker *c, isize lhs_count, Array<Operand> *operands, Array<AstNode *> rhs, bool allow_ok) {
+void check_unpack_arguments(Checker *c, Entity **lhs, isize lhs_count, Array<Operand> *operands, Array<AstNode *> rhs, bool allow_ok, bool *optional_ok_ = nullptr) {
 	bool optional_ok = false;
+	isize tuple_index = 0;
 	for_array(i, rhs) {
+		CheckerContext prev_context = c->context;
+		defer (c->context = prev_context);
+
 		Operand o = {};
+
+		if (lhs != nullptr && tuple_index < lhs_count) {
+			// NOTE(bill): override DeclInfo for dependency control
+			DeclInfo *decl = decl_info_of_entity(&c->info, lhs[tuple_index]);
+			if (decl) c->context.decl = decl;
+		}
+
 		check_expr_base(c, &o, rhs[i], nullptr);
 		if (o.mode == Addressing_NoValue) {
 			error_operand_no_value(&o);
 			o.mode = Addressing_Invalid;
 		}
-		// check_multi_expr(c, &o, rhs[i]);
 
 
 		if (o.type == nullptr || o.type->kind != Type_Tuple) {
@@ -5998,8 +6023,10 @@ bool check_unpack_arguments(Checker *c, isize lhs_count, Array<Operand> *operand
 				array_add(operands, ok);
 
 				optional_ok = true;
+				tuple_index += add_dependencies_from_unpacking(c, lhs, lhs_count, tuple_index, 2);
 			} else {
 				array_add(operands, o);
+				tuple_index += 1;
 			}
 		} else {
 			TypeTuple *tuple = &o.type->Tuple;
@@ -6007,10 +6034,13 @@ bool check_unpack_arguments(Checker *c, isize lhs_count, Array<Operand> *operand
 				o.type = tuple->variables[j]->type;
 				array_add(operands, o);
 			}
+
+			isize count = tuple->variables.count;
+			tuple_index += add_dependencies_from_unpacking(c, lhs, lhs_count, tuple_index, count);
 		}
 	}
 
-	return optional_ok;
+	if (optional_ok_) *optional_ok_ = optional_ok;
 }
 
 
@@ -6404,7 +6434,7 @@ CallArgumentData check_call_arguments(Checker *c, Operand *operand, Type *proc_t
 
 	} else {
 		array_init(&operands, heap_allocator(), 2*ce->args.count);
-		check_unpack_arguments(c, -1, &operands, ce->args, false);
+		check_unpack_arguments(c, nullptr, -1, &operands, ce->args, false);
 	}
 
 	if (operand->mode == Addressing_Overload) {
@@ -6644,7 +6674,7 @@ CallArgumentError check_polymorphic_struct_type(Checker *c, Operand *operand, As
 
 	} else {
 		array_init(&operands, heap_allocator(), 2*ce->args.count);
-		check_unpack_arguments(c, -1, &operands, ce->args, false);
+		check_unpack_arguments(c, nullptr, -1, &operands, ce->args, false);
 	}
 
 	CallArgumentError err = CallArgumentError_None;
diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index 8c7586a12..d6c8f654d 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -692,7 +692,7 @@ void check_stmt_internal(Checker *c, AstNode *node, u32 flags) {
 			// an extra allocation
 			Array<Operand> operands = {};
 			array_init(&operands, c->tmp_allocator, 2 * lhs_count);
-			check_unpack_arguments(c, lhs_count, &operands, as->rhs, true);
+			check_unpack_arguments(c, nullptr, lhs_count, &operands, as->rhs, true);
 
 			isize rhs_count = operands.count;
 			for_array(i, operands) {
@@ -849,7 +849,7 @@ void check_stmt_internal(Checker *c, AstNode *node, u32 flags) {
 			}
 		} else {
 			array_init(&operands, heap_allocator(), 2*rs->results.count);
-			check_unpack_arguments(c, -1, &operands, rs->results, false);
+			check_unpack_arguments(c, nullptr, -1, &operands, rs->results, false);
 		}
 
 
diff --git a/src/checker.cpp b/src/checker.cpp
index d40e05bfa..9f6ba76d5 100644
--- a/src/checker.cpp
+++ b/src/checker.cpp
@@ -181,10 +181,11 @@ struct DeclInfo {
 
 	AstNode *         type_expr;
 	AstNode *         init_expr;
+	Array<AstNode *>  init_expr_list;
 	AstNode *         proc_lit;      // AstNode_ProcLit
 	Type *            gen_proc_type; // Precalculated
 
-	Map<bool>         deps; // Key: Entity *
+	PtrSet<Entity *>  deps;
 	Array<BlockLabel> labels;
 };
 
@@ -273,6 +274,69 @@ struct CheckerFileNode {
 	i32        score; // Higher the score, the better
 };
 
+struct GraphNode;
+typedef PtrSet<GraphNode *> GraphNodeSet;
+
+void graph_node_set_destroy(GraphNodeSet *s) {
+	if (s->hashes.data != nullptr) {
+		ptr_set_destroy(s);
+	}
+}
+
+void graph_node_set_add(GraphNodeSet *s, GraphNode *n) {
+	if (s->hashes.data == nullptr) {
+		ptr_set_init(s, heap_allocator());
+	}
+	ptr_set_add(s, n);
+}
+
+bool graph_node_set_exists(GraphNodeSet *s, GraphNode *n) {
+	return ptr_set_exists(s, n);
+}
+
+void graph_node_set_remove(GraphNodeSet *s, GraphNode *n) {
+	ptr_set_remove(s, n);
+}
+
+
+struct GraphNode {
+	Entity *     entity; // Procedure, Variable, Constant
+	GraphNodeSet pred;
+	GraphNodeSet succ;
+	isize        index; // Index in array/queue
+	isize        dep_count;
+};
+
+
+void graph_node_destroy(GraphNode *n, gbAllocator a) {
+	graph_node_set_destroy(&n->pred);
+	graph_node_set_destroy(&n->succ);
+	gb_free(a, n);
+}
+
+
+int graph_node_cmp(GraphNode **data, isize i, isize j) {
+	GraphNode *x = data[i];
+	GraphNode *y = data[j];
+	isize a = x->entity->order_in_src;
+	isize b = y->entity->order_in_src;
+	if (x->dep_count < y->dep_count) return -1;
+	if (x->dep_count > y->dep_count) return +1;
+	return a < b ? -1 : b > a;
+}
+
+void graph_node_swap(GraphNode **data, isize i, isize j) {
+	GraphNode *x = data[i];
+	GraphNode *y = data[j];
+	data[i] = y;
+	data[j] = x;
+	x->index = j;
+	y->index = i;
+}
+
+
+
+
 struct CheckerContext {
 	Scope *    file_scope;
 	Scope *    scope;
@@ -303,8 +367,15 @@ struct CheckerInfo {
 	Map<DeclInfo *>       entities;        // Key: Entity *
 	Map<Entity *>         foreigns;        // Key: String
 	Map<AstFile *>        files;           // Key: String (full path)
+	Array<DeclInfo *>     variable_init_order;
+
+
 	Map<isize>            type_info_map;   // Key: Type *
 	isize                 type_info_count;
+
+	Entity *              entry_point;
+	PtrSet<Entity *>      minimum_dependency_map;
+
 };
 
 struct Checker {
@@ -372,8 +443,8 @@ void add_implicit_entity(Checker *c, AstNode *node, Entity *e);
 void init_declaration_info(DeclInfo *d, Scope *scope, DeclInfo *parent) {
 	d->parent = parent;
 	d->scope  = scope;
-	map_init(&d->deps, heap_allocator());
-	array_init(&d->labels,  heap_allocator());
+	ptr_set_init(&d->deps,                heap_allocator());
+	array_init  (&d->labels,              heap_allocator());
 }
 
 DeclInfo *make_declaration_info(gbAllocator a, Scope *scope, DeclInfo *parent) {
@@ -383,7 +454,8 @@ DeclInfo *make_declaration_info(gbAllocator a, Scope *scope, DeclInfo *parent) {
 }
 
 void destroy_declaration_info(DeclInfo *d) {
-	map_destroy(&d->deps);
+	ptr_set_destroy(&d->deps);
+	array_free(&d->labels);
 }
 
 bool decl_info_has_init(DeclInfo *d) {
@@ -626,7 +698,7 @@ void check_scope_usage(Checker *c, Scope *scope) {
 
 
 void add_dependency(DeclInfo *d, Entity *e) {
-	map_set(&d->deps, hash_entity(e), cast(bool)true);
+	ptr_set_add(&d->deps, e);
 }
 
 void add_declaration_dependency(Checker *c, Entity *e) {
@@ -634,10 +706,8 @@ void add_declaration_dependency(Checker *c, Entity *e) {
 		return;
 	}
 	if (c->context.decl != nullptr) {
-		DeclInfo **found = map_get(&c->info.entities, hash_entity(e));
-		if (found) {
-			add_dependency(c->context.decl, e);
-		}
+		DeclInfo *decl = decl_info_of_entity(&c->info, e);
+		if (decl) add_dependency(c->context.decl, e);
 	}
 }
 
@@ -744,8 +814,9 @@ void init_checker_info(CheckerInfo *i) {
 	map_init(&i->gen_types,     a);
 	map_init(&i->type_info_map, a);
 	map_init(&i->files,         a);
-	i->type_info_count = 0;
+	array_init(&i->variable_init_order, a);
 
+	i->type_info_count = 0;
 }
 
 void destroy_checker_info(CheckerInfo *i) {
@@ -761,6 +832,7 @@ void destroy_checker_info(CheckerInfo *i) {
 	map_destroy(&i->gen_types);
 	map_destroy(&i->type_info_map);
 	map_destroy(&i->files);
+	array_free(&i->variable_init_order);
 }
 
 
@@ -1049,6 +1121,7 @@ void add_entity_and_decl_info(Checker *c, AstNode *identifier, Entity *e, DeclIn
 	if (e->scope != nullptr) add_entity(c, e->scope, identifier, e);
 	add_entity_definition(&c->info, identifier, e);
 	map_set(&c->info.entities, hash_entity(e), d);
+	e->order_in_src = c->info.entities.entries.count;
 }
 
 
@@ -1253,7 +1326,7 @@ void add_curr_ast_file(Checker *c, AstFile *file) {
 }
 
 
-void add_dependency_to_map(Map<Entity *> *map, CheckerInfo *info, Entity *entity) {
+void add_dependency_to_map(PtrSet<Entity *> *map, CheckerInfo *info, Entity *entity) {
 	if (entity == nullptr) {
 		return;
 	}
@@ -1265,26 +1338,23 @@ void add_dependency_to_map(Map<Entity *> *map, CheckerInfo *info, Entity *entity
 		}
 	}
 
-	if (map_get(map, hash_entity(entity)) != nullptr) {
+	if (ptr_set_exists(map, entity)) {
 		return;
 	}
-	map_set(map, hash_entity(entity), entity);
-
 
+	ptr_set_add(map, entity);
 	DeclInfo *decl = decl_info_of_entity(info, entity);
-	if (decl == nullptr) {
-		return;
-	}
-
-	for_array(i, decl->deps.entries) {
-		Entity *e = cast(Entity *)decl->deps.entries[i].key.ptr;
-		add_dependency_to_map(map, info, e);
+	if (decl != nullptr) {
+		for_array(i, decl->deps.entries) {
+			Entity *e = decl->deps.entries[i].ptr;
+			add_dependency_to_map(map, info, e);
+		}
 	}
 }
 
-Map<Entity *> generate_minimum_dependency_map(CheckerInfo *info, Entity *start) {
-	Map<Entity *> map = {}; // Key: Entity *
-	map_init(&map, heap_allocator());
+PtrSet<Entity *> generate_minimum_dependency_map(CheckerInfo *info, Entity *start) {
+	PtrSet<Entity *> map = {}; // Key: Entity *
+	ptr_set_init(&map, heap_allocator());
 
 	for_array(i, info->definitions.entries) {
 		Entity *e = info->definitions.entries[i].value;
@@ -1309,8 +1379,101 @@ Map<Entity *> generate_minimum_dependency_map(CheckerInfo *info, Entity *start)
 	return map;
 }
 
-bool is_entity_in_dependency_map(Map<Entity *> *map, Entity *e) {
-	return map_get(map, hash_entity(e)) != nullptr;
+bool is_entity_a_dependency(Entity *e) {
+	if (e == nullptr) return false;
+	switch (e->kind) {
+	case Entity_Procedure:
+	case Entity_Variable:
+	case Entity_Constant:
+		return true;
+	}
+	return false;
+}
+
+Array<GraphNode *> generate_dependency_graph(CheckerInfo *info) {
+	gbAllocator a = heap_allocator();
+
+	Map<GraphNode *> M = {}; // Key: Entity *
+	map_init(&M, a);
+	defer (map_destroy(&M));
+	for_array(i, info->entities.entries) {
+		auto *entry = &info->entities.entries[i];
+		Entity *  e = cast(Entity *)entry->key.ptr;
+		DeclInfo *d = entry->value;
+		if (is_entity_a_dependency(e)) {
+			GraphNode *n = gb_alloc_item(a, GraphNode);
+			n->entity = e;
+			map_set(&M, hash_pointer(e), n);
+		}
+	}
+
+
+	// Calculate edges for graph M
+	for_array(i, M.entries) {
+		Entity *   e = cast(Entity *)M.entries[i].key.ptr;
+		GraphNode *n = M.entries[i].value;
+
+		DeclInfo *decl = decl_info_of_entity(info, e);
+		if (decl != nullptr) {
+			for_array(j, decl->deps.entries) {
+				auto entry = decl->deps.entries[j];
+				Entity *dep = entry.ptr;
+				if (dep && is_entity_a_dependency(dep)) {
+					GraphNode **m_ = map_get(&M, hash_pointer(dep));
+					if (m_ != nullptr) {
+						GraphNode *m = *m_;
+						graph_node_set_add(&n->succ, m);
+						graph_node_set_add(&m->pred, n);
+					}
+				}
+			}
+		}
+	}
+
+	Array<GraphNode *> G = {};
+	array_init(&G, a);
+
+	for_array(i, M.entries) {
+		auto *entry = &M.entries[i];
+		Entity *   e = cast(Entity *)entry->key.ptr;
+		GraphNode *n = entry->value;
+
+		if (e->kind == Entity_Procedure) {
+			// Connect each pred `p` of `n` with each succ `s` and frop
+			// the procedure node
+			for_array(j, n->pred.entries) {
+				GraphNode *p = cast(GraphNode *)n->pred.entries[j].ptr;
+
+				// Ignore self-cycles
+				if (p != n) {
+					// Each succ `s` of `n` becomes a succ of `p`, and
+					// each pred `p` of `n` becomes a pred of `s`
+					for_array(k, n->succ.entries) {
+						GraphNode *s = n->succ.entries[k].ptr;
+						// Ignore self-cycles
+						if (s != n) {
+							graph_node_set_add(&p->succ, s);
+							graph_node_set_add(&s->pred, p);
+							// Remove edge to `n`
+							graph_node_set_remove(&s->pred, n);
+						}
+					}
+					// Remove edge to `n`
+					graph_node_set_remove(&p->succ, n);
+				}
+			}
+		} else {
+			array_add(&G, n);
+		}
+	}
+
+	for_array(i, G) {
+		GraphNode *n = G[i];
+		n->index = i;
+		n->dep_count = n->succ.entries.count;
+	}
+
+	return G;
 }
 
 
@@ -1668,6 +1831,7 @@ void check_collect_entities(Checker *c, Array<AstNode *> nodes, bool is_file_sco
 					di->entities = entities;
 					di->type_expr = vd->type;
 					di->init_expr = vd->values[0];
+					di->init_expr_list = vd->values;
 
 
 					if (vd->flags & VarDeclFlag_thread_local) {
@@ -1676,6 +1840,7 @@ void check_collect_entities(Checker *c, Array<AstNode *> nodes, bool is_file_sco
 				}
 
 
+
 				for_array(i, vd->names) {
 					AstNode *name = vd->names[i];
 					AstNode *value = nullptr;
@@ -1705,7 +1870,7 @@ void check_collect_entities(Checker *c, Array<AstNode *> nodes, bool is_file_sco
 					entities[entity_count++] = e;
 
 					DeclInfo *d = di;
-					if (d == nullptr) {
+					if (d == nullptr || i > 0) {
 						AstNode *init_expr = value;
 						d = make_declaration_info(heap_allocator(), e->scope, c->context.decl);
 						d->type_expr = vd->type;
@@ -1719,6 +1884,10 @@ void check_collect_entities(Checker *c, Array<AstNode *> nodes, bool is_file_sco
 					di->entity_count = entity_count;
 				}
 
+				if (vd->values.count > 0 && entity_count != vd->values.count) {
+					error(decl, "Variable declarations in the global scope can only declare 1 variable at a time");
+				}
+
 				check_arity_match(c, vd);
 			} else {
 				for_array(i, vd->names) {
@@ -2271,6 +2440,134 @@ void check_import_entities(Checker *c, Map<Scope *> *file_scopes) {
 	}
 }
 
+Array<Entity *> find_entity_path(Map<DeclInfo *> *map, Entity *start, Entity *end, Map<Entity *> *visited = nullptr) {
+	Map<Entity *> visited_ = {};
+	bool made_visited = false;
+	if (visited == nullptr) {
+		made_visited = true;
+		map_init(&visited_, heap_allocator());
+		visited = &visited_;
+	}
+	defer (if (made_visited) {
+		map_destroy(&visited_);
+	});
+
+	Array<Entity *> empty_path = {};
+
+	HashKey key = hash_pointer(start);
+
+	if (map_get(visited, key) != nullptr) {
+		return empty_path;
+	}
+	map_set(visited, key, start);
+
+	DeclInfo **found = map_get(map, key);
+	if (found) {
+		DeclInfo *decl = *found;
+		for_array(i, decl->deps.entries) {
+			Entity *dep = decl->deps.entries[i].ptr;
+			if (dep == end) {
+				Array<Entity *> path = {};
+				array_init(&path, heap_allocator());
+				array_add(&path, dep);
+				return path;
+			}
+			Array<Entity *> next_path = find_entity_path(map, dep, end, visited);
+			if (next_path.count > 0) {
+				array_add(&next_path, dep);
+				return next_path;
+			}
+		}
+	}
+	return empty_path;
+}
+
+
+void calculate_variable_init_order(Checker *c) {
+	CheckerInfo *info = &c->info;
+	auto *m = &info->entities;
+
+	Array<GraphNode *> dep_graph = generate_dependency_graph(info);
+	defer ({
+		for_array(i, dep_graph) {
+			graph_node_destroy(dep_graph[i], heap_allocator());
+		}
+		array_free(&dep_graph);
+	});
+
+	// NOTE(bill): Priority queue
+	auto pq = priority_queue_create(dep_graph, graph_node_cmp, graph_node_swap);
+
+	PtrSet<DeclInfo *> emitted = {};
+	ptr_set_init(&emitted, heap_allocator());
+	defer (ptr_set_destroy(&emitted));
+
+	while (pq.queue.count > 0) {
+		GraphNode *n = priority_queue_pop(&pq);
+		Entity *e = n->entity;
+
+		if (n->dep_count > 0) {
+			// TODO(bill): print out the cyclic initialization order
+			auto path = find_entity_path(m, e, e);
+			defer (array_free(&path));
+
+			if (path.count > 0) {
+				Entity *e = path[0];
+				error(e->token, "Cyclic initialization of `%.*s`", LIT(e->token.string));
+				for (isize i = path.count-1; i >= 0; i--) {
+					error(e->token, "\t`%.*s` refers to", LIT(e->token.string));
+					e = path[i];
+				}
+				error(e->token, "\t`%.*s`", LIT(e->token.string));
+			}
+		}
+
+		for_array(i, n->pred.entries) {
+			GraphNode *p = n->pred.entries[i].ptr;
+			p->dep_count -= 1;
+			priority_queue_fix(&pq, p->index);
+		}
+
+		if (e == nullptr || e->kind != Entity_Variable) {
+			continue;
+		}
+		DeclInfo *d = decl_info_of_entity(info, e);
+
+		// if (!decl_info_has_init(d)) {
+		// 	continue;
+		// }
+
+		if (ptr_set_exists(&emitted, d)) {
+			continue;
+		}
+		ptr_set_add(&emitted, d);
+
+		// TODO(bill): add to init order
+
+		if (d->entities == nullptr) {
+			d->entities = gb_alloc_array(c->allocator, Entity *, 1);
+			d->entities[0] = e;
+			d->entity_count = 1;
+		}
+		array_add(&info->variable_init_order, d);
+	}
+
+	if (false) {
+		gb_printf("Variable Initialization Order:\n");
+		for_array(i, info->variable_init_order) {
+			DeclInfo *d = info->variable_init_order[i];
+			for (isize j = 0; j < d->entity_count; j++) {
+				Entity *e = d->entities[j];
+				if (j == 0) gb_printf("\t");
+				if (j > 0) gb_printf(", ");
+				gb_printf("`%.*s` %td", LIT(e->token.string), e->order_in_src);
+			}
+			gb_printf("\n");
+		}
+		gb_printf("\n");
+	}
+}
+
 
 void check_parsed_files(Checker *c) {
 	Map<Scope *> file_scopes; // Key: String (fullpath)
@@ -2355,6 +2652,25 @@ void check_parsed_files(Checker *c) {
 		check_proc_body(c, pi->token, pi->decl, pi->type, pi->body);
 	}
 
+	{
+		for_array(i, c->info.entities.entries) {
+			auto *entry = &c->info.entities.entries[i];
+			Entity *e = cast(Entity *)entry->key.ptr;
+			String name = e->token.string;
+			if (e->kind == Entity_Procedure && !e->scope->is_global) {
+				if (e->scope->is_init && name == "main") {
+					c->info.entry_point = e;
+					break;
+				}
+			}
+		}
+		c->info.minimum_dependency_map = generate_minimum_dependency_map(&c->info, c->info.entry_point);
+	}
+
+	// Calculate initialization order of global variables
+	calculate_variable_init_order(c);
+
+
 	// Add untyped expression values
 	for_array(i, c->info.untyped.entries) {
 		auto *entry = &c->info.untyped.entries[i];
diff --git a/src/common.cpp b/src/common.cpp
index 74fbbb019..06cb674dd 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -107,6 +107,8 @@ u128 fnv128a(void const *data, isize len) {
 }
 
 #include "map.cpp"
+#include "ptr_set.cpp"
+#include "priority_queue.cpp"
 
 
 
diff --git a/src/entity.cpp b/src/entity.cpp
index 21ef9095f..2b0b0c379 100644
--- a/src/entity.cpp
+++ b/src/entity.cpp
@@ -78,6 +78,8 @@ struct Entity {
 	Entity *   using_parent;
 	AstNode *  using_expr;
 
+	isize      order_in_src;
+
 	union {
 		struct {
 			ExactValue value;
diff --git a/src/ir.cpp b/src/ir.cpp
index c777280bd..714af2a6a 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -19,7 +19,7 @@ struct irModule {
 	String layout;
 	// String triple;
 
-	Map<Entity *>         min_dep_map;   // Key: Entity *
+	PtrSet<Entity *>      min_dep_map;
 	Map<irValue *>        values;        // Key: Entity *
 	Map<irValue *>        members;       // Key: String
 	Map<String>           entity_names;  // Key: Entity * of the typename
@@ -5783,7 +5783,7 @@ irValue *ir_build_cond(irProcedure *proc, AstNode *cond, irBlock *true_block, ir
 void ir_build_poly_proc(irProcedure *proc, AstNodeProcLit *pd, Entity *e) {
 	GB_ASSERT(pd->body != nullptr);
 
-	if (is_entity_in_dependency_map(&proc->module->min_dep_map, e) == false) {
+	if (ptr_set_exists(&proc->module->min_dep_map, e) == false) {
 		// NOTE(bill): Nothing depends upon it so doesn't need to be built
 		return;
 	}
@@ -5845,7 +5845,7 @@ void ir_build_constant_value_decl(irProcedure *proc, AstNodeValueDecl *vd) {
 				}
 			}
 
-			if (!polymorphic_struct && map_get(&proc->module->min_dep_map, hash_pointer(e)) == nullptr) {
+			if (!polymorphic_struct && !ptr_set_exists(&proc->module->min_dep_map, e)) {
 				continue;
 			}
 
@@ -5874,7 +5874,7 @@ void ir_build_constant_value_decl(irProcedure *proc, AstNodeValueDecl *vd) {
 					auto procs = *found;
 					for_array(i, procs) {
 						Entity *e = procs[i];
-						if (map_get(&proc->module->min_dep_map, hash_pointer(e)) == nullptr) {
+						if (!ptr_set_exists(&proc->module->min_dep_map, e)) {
 							continue;
 						}
 						DeclInfo *d = decl_info_of_entity(info, e);
@@ -7545,7 +7545,7 @@ void ir_gen_tree(irGen *s) {
 	}
 
 	isize global_variable_max_count = 0;
-	Entity *entry_point = nullptr;
+	Entity *entry_point = info->entry_point;
 	bool has_dll_main = false;
 	bool has_win_main = false;
 
@@ -7557,7 +7557,8 @@ void ir_gen_tree(irGen *s) {
 			global_variable_max_count++;
 		} else if (e->kind == Entity_Procedure && !e->scope->is_global) {
 			if (e->scope->is_init && name == "main") {
-				entry_point = e;
+				GB_ASSERT(e == entry_point);
+				// entry_point = e;
 			}
 			if ((e->Procedure.tags & ProcTag_export) != 0 ||
 			    (e->Procedure.link_name.len > 0) ||
@@ -7582,7 +7583,63 @@ void ir_gen_tree(irGen *s) {
 	array_init(&global_variables, m->tmp_allocator, global_variable_max_count);
 
 	m->entry_point_entity = entry_point;
-	m->min_dep_map = generate_minimum_dependency_map(info, entry_point);
+	m->min_dep_map = info->minimum_dependency_map;
+
+	for_array(i, info->variable_init_order) {
+		DeclInfo *d = info->variable_init_order[i];
+
+		for (isize j = 0; j < d->entity_count; j++) {
+			Entity *e = d->entities[j];
+
+			if (!e->scope->is_file) {
+				continue;
+			}
+
+			if (!ptr_set_exists(&m->min_dep_map, e)) {
+				continue;
+			}
+			DeclInfo *decl = decl_info_of_entity(info, e);
+			if (decl == nullptr) {
+				continue;
+			}
+
+			String name = e->token.string;
+			String original_name = name;
+			if (!e->scope->is_global) {
+				name = ir_mangle_name(s, e->token.pos.file, e);
+			}
+			map_set(&m->entity_names, hash_entity(e), name);
+
+			irValue *g = ir_value_global(a, e, nullptr);
+			g->Global.name = name;
+			g->Global.is_thread_local = e->Variable.is_thread_local;
+
+
+			irGlobalVariable var = {};
+			var.var = g;
+			var.decl = decl;
+
+			if (decl->init_expr != nullptr) {
+				if (is_type_any(e->type)) {
+				} else {
+					TypeAndValue tav = type_and_value_of_expr(info, decl->init_expr);
+					if (tav.mode != Addressing_Invalid) {
+						if (tav.value.kind != ExactValue_Invalid) {
+							ExactValue v = tav.value;
+							g->Global.value = ir_add_module_constant(m, tav.type, v);
+						}
+					}
+				}
+			}
+
+			// if (g->Global.value == nullptr) {
+				array_add(&global_variables, var);
+			// }
+
+			ir_module_add_value(m, e, g);
+			map_set(&m->members, hash_string(name), g);
+		}
+	}
 
 	for_array(i, info->entities.entries) {
 		auto *entry = &info->entities.entries[i];
@@ -7595,6 +7652,10 @@ void ir_gen_tree(irGen *s) {
 			continue;
 		}
 
+		if (e->kind == Entity_Variable) {
+			// NOTE(bill): Handled above as it requires a specific load order
+			continue;
+		}
 
 		bool polymorphic_struct = false;
 		if (e->type != nullptr && e->kind == Entity_TypeName) {
@@ -7604,7 +7665,7 @@ void ir_gen_tree(irGen *s) {
 			}
 		}
 
-		if (!polymorphic_struct && map_get(&m->min_dep_map, hash_entity(e)) == nullptr) {
+		if (!polymorphic_struct && !ptr_set_exists(&m->min_dep_map, e)) {
 			// NOTE(bill): Nothing depends upon it so doesn't need to be built
 			continue;
 		}
@@ -7622,7 +7683,6 @@ void ir_gen_tree(irGen *s) {
 		} else if (check_is_entity_overloaded(e)) {
 			name = ir_mangle_name(s, e->token.pos.file, e);
 		}
-
 		map_set(&m->entity_names, hash_entity(e), name);
 
 		switch (e->kind) {
@@ -7631,39 +7691,6 @@ void ir_gen_tree(irGen *s) {
 			ir_gen_global_type_name(m, e, name);
 			break;
 
-		case Entity_Variable: {
-			irValue *g = ir_value_global(a, e, nullptr);
-			g->Global.name = name;
-			g->Global.is_thread_local = e->Variable.is_thread_local;
-
-			irGlobalVariable var = {};
-			var.var = g;
-			var.decl = decl;
-
-			if (decl->init_expr != nullptr) {
-				if (is_type_any(e->type)) {
-
-				} else {
-					TypeAndValue tav = type_and_value_of_expr(info, decl->init_expr);
-					if (tav.mode != Addressing_Invalid) {
-						if (tav.value.kind != ExactValue_Invalid) {
-							ExactValue v = tav.value;
-							// if (v.kind != ExactValue_String) {
-								g->Global.value = ir_add_module_constant(m, tav.type, v);
-							// }
-						}
-					}
-				}
-			}
-
-			if (g->Global.value == nullptr) {
-				array_add(&global_variables, var);
-			}
-
-			ir_module_add_value(m, e, g);
-			map_set(&m->members, hash_string(name), g);
-		} break;
-
 		case Entity_Procedure: {
 			ast_node(pl, ProcLit, decl->proc_lit);
 			String original_name = name;
@@ -7863,52 +7890,7 @@ void ir_gen_tree(irGen *s) {
 			ir_emit_global_call(proc, "__init_context", args, 1);
 		}
 
-		// TODO(bill): Should do a dependency graph do check which order to initialize them in?
-		for_array(i, global_variables) {
-			irGlobalVariable *var = &global_variables[i];
-			if (var->decl->init_expr != nullptr) {
-				var->init = ir_build_expr(proc, var->decl->init_expr);
-			}
-		}
 
-		// NOTE(bill): Initialize constants first
-		for_array(i, global_variables) {
-			irGlobalVariable *var = &global_variables[i];
-			if (var->init != nullptr && var->init->kind == irValue_Constant) {
-				Type *t = type_deref(ir_type(var->var));
-				if (is_type_any(t)) {
-					// NOTE(bill): Edge case for `any` type
-					Type *var_type = default_type(ir_type(var->init));
-					irValue *g = ir_add_global_generated(proc->module, var_type, var->init);
-					irValue *data = ir_emit_struct_ep(proc, var->var, 0);
-					irValue *ti   = ir_emit_struct_ep(proc, var->var, 1);
-					ir_emit_store(proc, data, ir_emit_conv(proc, g, t_rawptr));
-					ir_emit_store(proc, ti,   ir_type_info(proc, var_type));
-				} else {
-					ir_emit_store(proc, var->var, var->init);
-				}
-			}
-		}
-
-		for_array(i, global_variables) {
-			irGlobalVariable *var = &global_variables[i];
-			if (var->init != nullptr && var->init->kind != irValue_Constant) {
-				Type *t = type_deref(ir_type(var->var));
-				if (is_type_any(t)) {
-					// NOTE(bill): Edge case for `any` type
-					Type *var_type = default_type(ir_type(var->init));
-					irValue *g = ir_add_global_generated(proc->module, var_type, var->init);
-					ir_emit_store(proc, g, var->init);
-
-					irValue *data = ir_emit_struct_ep(proc, var->var, 0);
-					irValue *ti   = ir_emit_struct_ep(proc, var->var, 1);
-					ir_emit_store(proc, data, ir_emit_conv(proc, g, t_rawptr));
-					ir_emit_store(proc, ti,   ir_type_info(proc, var_type));
-				} else {
-					ir_emit_store(proc, var->var, var->init);
-				}
-			}
-		}
 
 		{ // NOTE(bill): Setup type_info data
 			CheckerInfo *info = proc->module->info;
@@ -8312,6 +8294,31 @@ void ir_gen_tree(irGen *s) {
 			}
 		}
 
+		for_array(i, global_variables) {
+			irGlobalVariable *var = &global_variables[i];
+			if (var->decl->init_expr != nullptr)  {
+				var->init = ir_build_expr(proc, var->decl->init_expr);
+			}
+
+			if (var->init != nullptr) {
+				Type *t = type_deref(ir_type(var->var));
+
+				if (is_type_any(t)) {
+					// NOTE(bill): Edge case for `any` type
+					Type *var_type = default_type(ir_type(var->init));
+					irValue *g = ir_add_global_generated(proc->module, var_type, var->init);
+					ir_emit_store(proc, g, var->init);
+
+					irValue *data = ir_emit_struct_ep(proc, var->var, 0);
+					irValue *ti   = ir_emit_struct_ep(proc, var->var, 1);
+					ir_emit_store(proc, data, ir_emit_conv(proc, g, t_rawptr));
+					ir_emit_store(proc, ti,   ir_type_info(proc, var_type));
+				} else {
+					ir_emit_store(proc, var->var, var->init);
+				}
+			}
+		}
+
 		ir_end_procedure_body(proc);
 	}
 
diff --git a/src/parser.cpp b/src/parser.cpp
index de2da964a..e504a0d62 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -5086,10 +5086,11 @@ ParseFileError parse_files(Parser *p, String init_filename) {
 		array_add(&p->imports, runtime_file);
 		shared_file_count++;
 	}
+
 	array_add(&p->imports, init_imported_file);
 	p->init_fullpath = init_fullpath;
 
-
+/*
 	// IMPORTANT TODO(bill): Figure out why this doesn't work on *nix sometimes
 #if USE_THREADED_PARSER && defined(GB_SYSTEM_WINDOWS)
 	isize thread_count = gb_max(build_context.thread_count, 1);
@@ -5148,14 +5149,15 @@ ParseFileError parse_files(Parser *p, String init_filename) {
 			}
 		}
 	}
-#else
-	for_array(i, p->imports) {
-		ParseFileError err = parse_import(p, p->imports[i]);
+#else */
+	isize import_index = 0;
+	for (; import_index < p->imports.count; import_index++) {
+		ParseFileError err = parse_import(p, p->imports[import_index]);
 		if (err != ParseFile_None) {
 			return err;
 		}
 	}
-#endif
+// #endif
 
 	for_array(i, p->files) {
 		p->total_token_count += p->files[i].tokens.count;
diff --git a/src/ssa.cpp b/src/ssa.cpp
index 5862cca20..25afef118 100644
--- a/src/ssa.cpp
+++ b/src/ssa.cpp
@@ -159,7 +159,7 @@ struct ssaModule {
 	gbAllocator        tmp_allocator;
 	gbArena            tmp_arena;
 
-	Map<Entity *>      min_dep_map; // Key: Entity *
+	PtrSet<Entity *>   min_dep_map;
 	Map<ssaValue *>    values;      // Key: Entity *
 	// List of registers for the specific architecture
 	Array<ssaRegister> registers;
@@ -2464,7 +2464,7 @@ bool ssa_generate(Parser *parser, CheckerInfo *info) {
 			continue;
 		}
 
-		if (map_get(&m.min_dep_map, hash_pointer(e)) == nullptr) {
+		if (!ptr_set_exists(&m.min_dep_map, e)) {
 			// NOTE(bill): Nothing depends upon it so doesn't need to be built
 			continue;
 		}