`map` is internally backed by a pointer (i.e. a "reference type")

4 files changed, 95 insertions, 63 deletions

diff --git a/src/check_type.cpp b/src/check_type.cpp
index 6fee664d5..8374fd269 100644
--- a/src/check_type.cpp
+++ b/src/check_type.cpp
@@ -1844,7 +1844,8 @@ void generate_map_internal_types(gbAllocator a, Type *type) {
 
 	type_set_offsets(a, generated_struct_type);
 	type->Map.generated_struct_type = generated_struct_type;
-	type->Map.lookup_result_type = make_optional_ok_type(a, value);
+	type->Map.internal_type         = make_type_pointer(a, generated_struct_type);
+	type->Map.lookup_result_type    = make_optional_ok_type(a, value);
 }
 
 void check_map_type(Checker *c, Type *type, AstNode *node) {
diff --git a/src/ir.cpp b/src/ir.cpp
index d88eac3f8..b50a98655 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -1733,8 +1733,8 @@ void ir_emit_startup_runtime(irProcedure *proc) {
 irValue *ir_emit_struct_ep(irProcedure *proc, irValue *s, i32 index);
 irValue *ir_emit_comp(irProcedure *proc, TokenKind op_kind, irValue *left, irValue *right);
 
-irValue *ir_gen_map_header(irProcedure *proc, irValue *map_val, Type *map_type) {
-	GB_ASSERT_MSG(is_type_pointer(ir_type(map_val)), "%s", type_to_string(ir_type(map_val)));
+irValue *ir_gen_map_header(irProcedure *proc, irValue *map_val_ptr, Type *map_type) {
+	GB_ASSERT_MSG(is_type_pointer(ir_type(map_val_ptr)), "%s", type_to_string(ir_type(map_val_ptr)));
 	gbAllocator a = proc->module->allocator;
 	irValue *h = ir_add_local_generated(proc, t_map_header);
 	map_type = base_type(map_type);
@@ -1744,7 +1744,7 @@ irValue *ir_gen_map_header(irProcedure *proc, irValue *map_val, Type *map_type)
 
 	// NOTE(bill): Removes unnecessary allocation if split gep
 	irValue *gep0 = ir_emit_struct_ep(proc, h, 0);
-	irValue *m = ir_emit_conv(proc, map_val, type_deref(ir_type(gep0)));
+	irValue *m = ir_emit_conv(proc, map_val_ptr, type_deref(ir_type(gep0)));
 	ir_emit_store(proc, gep0, m);
 
 	if (is_type_string(key_type)) {
@@ -2536,14 +2536,18 @@ irValue *ir_emit_struct_ep(irProcedure *proc, irValue *s, i32 index) {
 		case 2: result_type = t_int_ptr;                                      break;
 		case 3: result_type = t_allocator_ptr;                                break;
 		}
-	} else if (is_type_map(t)) {
+	} /* else if (is_type_map(t)) {
 		generate_map_internal_types(a, t);
+		Type *itp = make_type_pointer(a, t->Map.internal_type);
+		s = ir_emit_load(proc, ir_emit_transmute(proc, s, itp));
+
 		Type *gst = t->Map.generated_struct_type;
+		GB_ASSERT(gst->kind == Type_Struct);
 		switch (index) {
 		case 0: result_type = make_type_pointer(a, gst->Struct.fields[0]->type); break;
 		case 1: result_type = make_type_pointer(a, gst->Struct.fields[1]->type); break;
 		}
-	}else {
+	} */else {
 		GB_PANIC("TODO(bill): struct_gep type: %s, %d", type_to_string(ir_type(s)), index);
 	}
 
@@ -2611,15 +2615,15 @@ irValue *ir_emit_struct_ev(irProcedure *proc, irValue *s, i32 index) {
 		}
 		break;
 
-	case Type_Map: {
-		generate_map_internal_types(a, t);
-		Type *gst = t->Map.generated_struct_type;
-		switch (index) {
-		case 0: result_type = gst->Struct.fields[0]->type; break;
-		case 1: result_type = gst->Struct.fields[1]->type; break;
-		}
-		break;
-	}
+	// case Type_Map: {
+	// 	generate_map_internal_types(a, t);
+	// 	Type *gst = t->Map.generated_struct_type;
+	// 	switch (index) {
+	// 	case 0: result_type = gst->Struct.fields[0]->type; break;
+	// 	case 1: result_type = gst->Struct.fields[1]->type; break;
+	// 	}
+	// 	break;
+	// }
 
 	default:
 		GB_PANIC("TODO(bill): struct_ev type: %s, %d", type_to_string(ir_type(s)), index);
@@ -6192,10 +6196,6 @@ void ir_build_range_indexed(irProcedure *proc, irValue *expr, Type *val_type, ir
 	irBlock *done = nullptr;
 	irBlock *body = nullptr;
 
-	irValue *key = nullptr;
-	if (expr_type->kind == Type_Map) {
-		key = ir_add_local_generated(proc, expr_type->Map.key);
-	}
 
 	irValue *index = ir_add_local_generated(proc, t_int);
 	ir_emit_store(proc, index, ir_const_int(proc->module->allocator, -1));
@@ -6210,6 +6210,7 @@ void ir_build_range_indexed(irProcedure *proc, irValue *expr, Type *val_type, ir
 	body = ir_new_block(proc, nullptr, "for.index.body");
 	done = ir_new_block(proc, nullptr, "for.index.done");
 	if (count == nullptr) {
+		GB_ASSERT(count_ptr != nullptr);
 		count = ir_emit_load(proc, count_ptr);
 	}
 	irValue *cond = ir_emit_comp(proc, Token_Lt, incr, count);
@@ -6217,52 +6218,59 @@ void ir_build_range_indexed(irProcedure *proc, irValue *expr, Type *val_type, ir
 	ir_start_block(proc, body);
 
 	idx = ir_emit_load(proc, index);
-	if (val_type != nullptr) {
-		switch (expr_type->kind) {
-		case Type_Array: {
+	switch (expr_type->kind) {
+	case Type_Array: {
+		if (val_type != nullptr) {
 			val = ir_emit_load(proc, ir_emit_array_ep(proc, expr, idx));
-			break;
 		}
-		case Type_Slice: {
+		break;
+	}
+	case Type_Slice: {
+		if (val_type != nullptr) {
 			irValue *elem = ir_slice_elem(proc, expr);
 			val = ir_emit_load(proc, ir_emit_ptr_offset(proc, elem, idx));
-			break;
 		}
-		case Type_DynamicArray: {
+		break;
+	}
+	case Type_DynamicArray: {
+		if (val_type != nullptr) {
 			irValue *elem = ir_emit_struct_ep(proc, expr, 0);
 			elem = ir_emit_load(proc, elem);
 			val = ir_emit_load(proc, ir_emit_ptr_offset(proc, elem, idx));
-			break;
 		}
-		case Type_Map: {
-			irValue *entries = ir_emit_struct_ep(proc, expr, 1);
-			irValue *elem = ir_emit_struct_ep(proc, entries, 0);
-			elem = ir_emit_load(proc, elem);
+		break;
+	}
+	case Type_Map: {
+		irValue *key = ir_add_local_generated(proc, expr_type->Map.key);
 
-			irValue *entry = ir_emit_ptr_offset(proc, elem, idx);
-			val = ir_emit_load(proc, ir_emit_struct_ep(proc, entry, 2));
+		Type *itp = make_type_pointer(proc->module->allocator, expr_type->Map.internal_type);
+		irValue *data_ptr = ir_emit_transmute(proc, expr, itp);
+		irValue *internal_ptr = ir_emit_load(proc, data_ptr);
 
-			irValue *hash = ir_emit_struct_ep(proc, entry, 0);
-			if (is_type_string(expr_type->Map.key)) {
-				irValue *str = ir_emit_struct_ep(proc, hash, 1);
-				ir_emit_store(proc, key, ir_emit_load(proc, str));
-			} else {
-				irValue *hash_ptr = ir_emit_struct_ep(proc, hash, 0);
-				hash_ptr = ir_emit_conv(proc, hash_ptr, ir_type(key));
-				ir_emit_store(proc, key, ir_emit_load(proc, hash_ptr));
-			}
+		irValue *entries = ir_emit_struct_ep(proc, internal_ptr, 1);
+		irValue *elem = ir_emit_struct_ep(proc, entries, 0);
+		elem = ir_emit_load(proc, elem);
 
+		irValue *entry = ir_emit_ptr_offset(proc, elem, idx);
+		val = ir_emit_load(proc, ir_emit_struct_ep(proc, entry, 2));
 
-			break;
-		}
-		default:
-			GB_PANIC("Cannot do range_indexed of %s", type_to_string(expr_type));
-			break;
+		irValue *hash = ir_emit_struct_ep(proc, entry, 0);
+		if (is_type_string(expr_type->Map.key)) {
+			irValue *str = ir_emit_struct_ep(proc, hash, 1);
+			ir_emit_store(proc, key, ir_emit_load(proc, str));
+		} else {
+			irValue *hash_ptr = ir_emit_struct_ep(proc, hash, 0);
+			hash_ptr = ir_emit_conv(proc, hash_ptr, ir_type(key));
+			ir_emit_store(proc, key, ir_emit_load(proc, hash_ptr));
 		}
-	}
 
-	if (key != nullptr) {
 		idx = ir_emit_load(proc, key);
+
+		break;
+	}
+	default:
+		GB_PANIC("Cannot do range_indexed of %s", type_to_string(expr_type));
+		break;
 	}
 
 	if (val_)  *val_  = val;
@@ -6863,7 +6871,6 @@ void ir_build_stmt_internal(irProcedure *proc, AstNode *node) {
 			ir_emit_if(proc, cond, body, done);
 			ir_start_block(proc, body);
 
-
 			irValue *val_ptr = ir_emit_ptr_offset(proc, values_data, offset);
 			ir_emit_increment(proc, offset_);
 
@@ -6885,14 +6892,34 @@ void ir_build_stmt_internal(irProcedure *proc, AstNode *node) {
 			switch (et->kind) {
 			case Type_Map: {
 				is_map = true;
+				gbAllocator a = proc->module->allocator;
 				irAddr addr = ir_build_addr(proc, rs->expr);
 				irValue *map = ir_addr_get_ptr(proc, addr);
 				if (is_type_pointer(type_deref(ir_addr_type(addr)))) {
 					map = ir_addr_load(proc, addr);
 				}
-				irValue *entries_ptr = ir_emit_struct_ep(proc, map, 1);
-				irValue *count_ptr = ir_emit_struct_ep(proc, entries_ptr, 1);
-				ir_build_range_indexed(proc, map, val1_type, count_ptr, &val, &key, &loop, &done);
+				irValue *count_ptr = ir_add_local_generated(proc, t_int);
+				irValue *count_ptr_ptr = ir_add_local_generated(proc, t_int_ptr);
+				ir_emit_store(proc, count_ptr_ptr, count_ptr);
+
+				irBlock *not_nil_block = ir_new_block(proc, nullptr, "map.not.nil.block");
+				irBlock *end_nil_block = ir_new_block(proc, nullptr, "map.end.nil.block");
+				{
+					Type *itp = make_type_pointer(a, et->Map.internal_type);
+					irValue *data_ptr = ir_emit_transmute(proc, map, itp);
+					irValue *internal_ptr = ir_emit_load(proc, data_ptr);
+
+					irValue *cond = ir_emit_comp(proc, Token_NotEq, internal_ptr, v_raw_nil);
+					ir_emit_if(proc, cond, not_nil_block, end_nil_block);
+					ir_start_block(proc, not_nil_block);
+
+					irValue *entries_ptr = ir_emit_struct_ep(proc, internal_ptr, 1);
+					irValue *cp = ir_emit_struct_ep(proc, entries_ptr, 1);
+					ir_emit_store(proc, count_ptr_ptr, cp);
+					ir_emit_jump(proc, end_nil_block);
+				}
+				ir_start_block(proc, end_nil_block);
+				ir_build_range_indexed(proc, map, val1_type, ir_emit_load(proc, count_ptr_ptr), &val, &key, &loop, &done);
 				break;
 			}
 			case Type_Array: {
@@ -6948,6 +6975,7 @@ void ir_build_stmt_internal(irProcedure *proc, AstNode *node) {
 			}
 		}
 
+
 		irAddr val0_addr = {};
 		irAddr val1_addr = {};
 		if (val0_type) val0_addr = ir_build_addr(proc, rs->val0);
diff --git a/src/ir_print.cpp b/src/ir_print.cpp
index 8a67cb6e2..2c341ad57 100644
--- a/src/ir_print.cpp
+++ b/src/ir_print.cpp
@@ -427,8 +427,8 @@ void ir_print_type(irFileBuffer *f, irModule *m, Type *t) {
 
 	case Type_Map: {
 		generate_map_internal_types(m->allocator, t);
-		GB_ASSERT(t->Map.generated_struct_type != nullptr);
-		ir_print_type(f, m, t->Map.generated_struct_type);
+		GB_ASSERT(t->Map.internal_type != nullptr);
+		ir_print_type(f, m, t->Map.internal_type);
 		break;
 	}
 
diff --git a/src/types.cpp b/src/types.cpp
index 453f4fd71..9ccb97a6e 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -162,6 +162,7 @@ struct TypeStruct {
 		Type * value;                                     \
 		Type * entry_type;                                \
 		Type * generated_struct_type;                     \
+		Type * internal_type;                             \
 		Type * lookup_result_type;                        \
 	})                                                    \
 	TYPE_KIND(BitFieldValue, struct { u32 bits; })        \
@@ -1365,10 +1366,10 @@ i64 union_tag_size(gbAllocator a, Type *u) {
 		return u->Union.tag_size;
 	}
 
-	i64 tag_size = type_align_of(a, u);
-	if (tag_size < 1) {
-		tag_size = build_context.word_size;
-	}
+	u64 n = cast(u64)u->Union.variants.count;
+	i64 bytes = next_pow2(cast(i64)(floor_log2(n)/8 + 1));
+	i64 tag_size = gb_max(bytes, 1);
+
 	u->Union.tag_size = tag_size;
 	return tag_size;
 }
@@ -1383,7 +1384,7 @@ Type *union_tag_type(gbAllocator a, Type *u) {
 	case 16: return t_u128;
 	}
 	GB_PANIC("Invalid union_tag_size");
-	return t_int;
+	return t_uint;
 }
 
 
@@ -1870,7 +1871,8 @@ i64 type_align_of_internal(gbAllocator allocator, Type *t, TypePath *path) {
 
 	case Type_Map:
 		generate_map_internal_types(allocator, t);
-		return type_align_of_internal(allocator, t->Map.generated_struct_type, path);
+		// return type_align_of_internal(allocator, t->Map.generated_struct_type, path);
+		return build_context.word_size;
 
 	case Type_Enum:
 		return type_align_of_internal(allocator, t->Enum.base_type, path);
@@ -2063,7 +2065,8 @@ i64 type_size_of_internal(gbAllocator allocator, Type *t, TypePath *path) {
 
 	case Type_Map:
 		generate_map_internal_types(allocator, t);
-		return type_size_of_internal(allocator, t->Map.generated_struct_type, path);
+		// return type_size_of_internal(allocator, t->Map.generated_struct_type, path);
+		return build_context.word_size;
 
 	case Type_Tuple: {
 		i64 count, align, size;
@@ -2101,7 +2104,7 @@ i64 type_size_of_internal(gbAllocator allocator, Type *t, TypePath *path) {
 		}
 
 		// NOTE(bill): Align to tag
-		i64 tag_size = gb_max(align, 1);
+		i64 tag_size = union_tag_size(allocator, t);
 		i64 size = align_formula(max, tag_size);
 		// NOTE(bill): Calculate the padding between the common fields and the tag
 		t->Union.tag_size = tag_size;