commit 8b17d5954c0c53b8d57e5f9c1598408f99af6621
parent c944388851200927212f4f113b53132881cbf3a9
Author: Drew DeVault <sir@cmpwn.com>
Date: Sun, 10 Jan 2021 10:58:27 -0500
types: refactor struct fields into separate struct
This also introduces a (partially implemented) c_compat boolean which is
used to determine if we should emit a QBE type which is ABI-compatible
with C for a given struct or union type (the answer is "no" in the case
of explicit offsets, which is a GNU C extension).
Diffstat:
5 files changed, 44 insertions(+), 30 deletions(-)
diff --git a/include/expr.h b/include/expr.h
@@ -178,7 +178,7 @@ struct expression_return {
};
struct expression_struct {
- const struct type_struct_union *field;
+ const struct struct_field *field;
struct expression *value;
struct expression_struct *next;
};
diff --git a/include/types.h b/include/types.h
@@ -80,11 +80,21 @@ struct type_pointer {
unsigned int flags;
};
-struct type_struct_union {
+struct struct_field {
char *name;
const struct type *type;
size_t offset;
- struct type_struct_union *next;
+ struct struct_field *next;
+};
+
+struct type_struct_union {
+ // c_compat is false if explicit offsets are used, or if the type is a
+ // union. The latter is actually still C-compatible, but this is an
+ // implementation detail which changes the way the QBE IL is generated,
+ // and in the case of unions, the altered behavior for explicit-offset
+ // structs is also correct for all cases of unions.
+ bool c_compat;
+ struct struct_field *fields;
};
enum type_flags {
@@ -99,12 +109,12 @@ struct type {
struct type_array array;
struct type_func func;
struct type_pointer pointer;
- struct type_struct_union *struct_union;
+ struct type_struct_union struct_union;
};
};
const struct type *type_dereference(const struct type *type);
-const struct type_struct_union *type_lookup_field(
+const struct struct_field *type_lookup_field(
const struct type *type, const char *name);
const char *type_storage_unparse(enum type_storage storage);
diff --git a/src/check.c b/src/check.c
@@ -688,7 +688,7 @@ check_expr_struct(struct context *ctx,
tfield = stype.struct_union.next;
sexpr = &expr->_struct;
while (tfield) {
- const struct type_struct_union *field = type_lookup_field(
+ const struct struct_field *field = type_lookup_field(
expr->result, tfield->field.name);
// TODO: Use more specific error location
expect(&aexpr->loc,
diff --git a/src/type_store.c b/src/type_store.c
@@ -297,7 +297,7 @@ type_hash(struct type_store *store, const struct type *type)
assert(0); // TODO
case TYPE_STORAGE_STRUCT:
case TYPE_STORAGE_UNION:
- for (const struct type_struct_union *field = type->struct_union;
+ for (const struct struct_field *field = type->struct_union.fields;
field; field = field->next) {
hash = djb2_s(hash, field->name);
hash = djb2(hash, type_hash(store, field->type));
@@ -389,8 +389,9 @@ type_eq_type(struct type_store *store,
assert(0); // TODO
case TYPE_STORAGE_STRUCT:
case TYPE_STORAGE_UNION:
- for (const struct type_struct_union *afield = a->struct_union,
- *bfield = b->struct_union; afield && bfield;
+ for (const struct struct_field *afield = a->struct_union.fields,
+ *bfield = b->struct_union.fields;
+ afield && bfield;
afield = afield->next, bfield = bfield->next) {
if (!!afield->next != !!bfield->next) {
return false;
@@ -414,20 +415,20 @@ type_eq_type(struct type_store *store,
}
static void
-struct_insert_field(struct type_store *store, struct type_struct_union **type,
+struct_insert_field(struct type_store *store, struct struct_field **fields,
enum type_storage storage, size_t *size, size_t *usize, size_t *align,
const struct ast_struct_union_type *atype)
{
assert(atype->member_type == MEMBER_TYPE_FIELD);
- while (*type && strcmp((*type)->name, atype->field.name) < 0) {
- type = &(*type)->next;
+ while (*fields && strcmp((*fields)->name, atype->field.name) < 0) {
+ fields = &(*fields)->next;
}
- struct type_struct_union *field = *type;
+ struct struct_field *field = *fields;
// TODO: Bubble this error up
assert(field == NULL || strcmp(field->name, atype->field.name) != 0);
- *type = xcalloc(1, sizeof(struct type_struct_union));
- (*type)->next = field;
- field = *type;
+ *fields = xcalloc(1, sizeof(struct struct_field));
+ (*fields)->next = field;
+ field = *fields;
field->name = strdup(atype->field.name);
field->type = type_store_lookup_atype(store, atype->field.type);
@@ -443,7 +444,7 @@ struct_insert_field(struct type_store *store, struct type_struct_union **type,
static void
struct_init_from_atype(struct type_store *store, enum type_storage storage,
- size_t *size, size_t *align, struct type_struct_union **type,
+ size_t *size, size_t *align, struct struct_field **fields,
const struct ast_struct_union_type *atype)
{
// TODO: fields with size SIZE_UNDEFINED
@@ -453,12 +454,12 @@ struct_init_from_atype(struct type_store *store, enum type_storage storage,
size_t sub = *size;
switch (atype->member_type) {
case MEMBER_TYPE_FIELD:
- struct_insert_field(store, type, storage, size, &usize,
+ struct_insert_field(store, fields, storage, size, &usize,
align, atype);
break;
case MEMBER_TYPE_EMBEDDED:
struct_init_from_atype(store, atype->embedded->storage,
- &sub, align, type,
+ &sub, align, fields,
&atype->embedded->struct_union);
if (storage == TYPE_STORAGE_UNION) {
usize = sub > usize ? sub : usize;
@@ -549,9 +550,11 @@ type_init_from_atype(struct type_store *store,
case TYPE_STORAGE_SLICE:
assert(0); // TODO
case TYPE_STORAGE_STRUCT:
+ type->struct_union.c_compat = true;
+ // Fallthrough
case TYPE_STORAGE_UNION:
struct_init_from_atype(store, type->storage, &type->size,
- &type->align, &type->struct_union,
+ &type->align, &type->struct_union.fields,
&atype->struct_union);
break;
case TYPE_STORAGE_TAGGED_UNION:
@@ -635,17 +638,18 @@ type_init_from_type(struct type_store *store,
assert(0); // TODO
case TYPE_STORAGE_STRUCT:
case TYPE_STORAGE_UNION:;
- struct type_struct_union **next = &new->struct_union;
- for (const struct type_struct_union *ofield = old->struct_union;
+ struct struct_field **next = &new->struct_union.fields;
+ for (const struct struct_field *ofield = old->struct_union.fields;
ofield; ofield = ofield->next) {
- struct type_struct_union *field = *next =
- xcalloc(sizeof(struct type_struct_union), 1);
+ struct struct_field *field = *next =
+ xcalloc(sizeof(struct struct_field), 1);
next = &field->next;
field->name = ofield->name;
field->type =
type_store_lookup_type(store, ofield->type);
field->offset = ofield->offset;
}
+ new->struct_union.c_compat = old->struct_union.c_compat;
new->size = old->size;
new->align = old->align;
break;
diff --git a/src/types.c b/src/types.c
@@ -12,19 +12,19 @@ type_dereference(const struct type *type)
return type_dereference(type->pointer.referent);
}
-const struct type_struct_union *
+const struct struct_field *
type_lookup_field(const struct type *type, const char *name)
{
// TODO: We should consider lowering unions into structs with explicit
// offsets
assert(type->storage == TYPE_STORAGE_STRUCT
|| type->storage == TYPE_STORAGE_UNION);
- struct type_struct_union *typesu = type->struct_union;
- while (typesu) {
- if (strcmp(typesu->name, name) == 0) {
- return typesu;
+ struct struct_field *field = type->struct_union.fields;
+ while (field) {
+ if (strcmp(field->name, name) == 0) {
+ return field;
}
- typesu = typesu->next;
+ field = field->next;
}
return NULL;
}
