initial dietc commit

1 files changed, 78 insertions, 0 deletions

diff --git a/type_helpers.c b/type_helpers.c
new file mode 100644
index 0000000..0f6b022
--- /dev/null
+++ b/type_helpers.c
@@ -0,0 +1,78 @@
+#include <stddef.h>
+#include "chibicc.h"
+
+unsigned long hash_type(Type *type) {
+  unsigned long hash = 6997;
+  if (!type) return hash;
+  if (type->hashing) return hash;
+  type->hashing = 1;
+#define EXTEND_HASH(v) hash = (hash * 33) ^ (size_t)(v)
+  EXTEND_HASH(type->kind);
+  EXTEND_HASH(type->size);
+  EXTEND_HASH(type->align);
+  EXTEND_HASH(type->is_unsigned);
+  EXTEND_HASH(type->is_atomic);
+  // EXTEND_HASH(hash_type(type->origin));
+
+  EXTEND_HASH(hash_type(type->base));
+  EXTEND_HASH(type->array_len);
+  EXTEND_HASH(type->vla_len);
+  EXTEND_HASH(type->vla_size);
+  EXTEND_HASH(type->members);
+
+  // TODO: assume the members pointers are actually same?
+  // for (Member *m = type->members; m; m = m->next) {
+  //   EXTEND_HASH(hash_type(m->ty));
+  //   EXTEND_HASH(m->name); // token
+  //   EXTEND_HASH(m->idx);
+  //   EXTEND_HASH(m->align);
+  //   EXTEND_HASH(m->offset);
+  //   EXTEND_HASH(m->is_bitfield);
+  //   EXTEND_HASH(m->bit_offset);
+  //   EXTEND_HASH(m->bit_width);
+  // }
+  EXTEND_HASH(type->is_flexible);
+  EXTEND_HASH(type->is_packed);
+
+  EXTEND_HASH(hash_type(type->return_ty));
+  EXTEND_HASH(hash_type(type->params));
+  EXTEND_HASH(type->is_variadic);
+  // EXTEND_HASH(type->next);
+
+  type->hashing = 0;
+  return hash;
+}
+
+int definitely_same_type(Type *type1, Type *type2) {
+  if (!type1 || !type2) return type1 == type2;
+  if (type1->hashing != type2->hashing) return 0;
+  if (type1->hashing) return type1 == type2;
+  type1->hashing = 1;
+  type2->hashing = 1;
+#define FIELD_CHECK(field) if (type1->field != type2->field) goto disequal
+#define RECURSE_CHECK(field) if (!definitely_same_type(type1->field, type2->field)) goto disequal
+  FIELD_CHECK(kind);
+  FIELD_CHECK(size);
+  FIELD_CHECK(align);
+  FIELD_CHECK(is_unsigned);
+  FIELD_CHECK(is_atomic);
+  // RECURSE_CHECK(origin);
+  RECURSE_CHECK(base);
+  FIELD_CHECK(array_len);
+  FIELD_CHECK(vla_len);
+  FIELD_CHECK(vla_size);
+  FIELD_CHECK(members);
+  FIELD_CHECK(is_flexible);
+  FIELD_CHECK(is_packed);
+  RECURSE_CHECK(return_ty);
+  FIELD_CHECK(params);
+  FIELD_CHECK(is_variadic);
+  // RECURSE_CHECK(next);
+  type1->hashing = 0;
+  type2->hashing = 0;
+  return 1;
+disequal:
+  type1->hashing = 0;
+  type2->hashing = 0;
+  return 0;
+}