.allowlist_function("printbuf.*")
.blocklist_type("rhash_lock_head")
.blocklist_type("srcu_struct")
+ .blocklist_type("bch_ioctl_data.*")
.allowlist_var("BCH_.*")
.allowlist_var("KEY_SPEC_.*")
.allowlist_var("Fix753_.*")
.expect("Writing to output file failed for: `keyutils.rs`");
}
-// rustc has a limitation where it does not allow structs to have both a "packed" and "align"
-// attribute. This means that bindgen cannot copy all attributes from some C types, like struct
-// bkey, that are both packed and aligned.
+// rustc has a limitation where it does not allow structs with a "packed" attribute to contain a
+// member with an "align(N)" attribute. There are a few types in bcachefs with this problem. We can
+// "fix" these types by stripping off "packed" from the outer type, or "align(N)" from the inner
+// type. For all of the affected types, stripping "packed" from the outer type happens to preserve
+// the same layout in Rust as in C.
//
-// bindgen tries to handle this situation smartly and for many types it will only apply a
-// "packed(N)" attribute if that is good enough. However, there are a few types where bindgen
-// does end up generating both a packed(N) and align(N) attribute. These types can't be compiled
-// by rustc.
+// Some types are only affected on attributes on architectures where the natural alignment of u64
+// is 4 instead of 8, for example i686 or ppc64: struct bch_csum and struct bch_sb_layout have
+// "align(8)" added on such architecutres. These types are included by several "packed" types:
+// - bch_extent_crc128
+// - jset
+// - btree_node_entry
+// - bch_sb
//
-// To work around this, we can remove either the "packed" or "align" attribute. It happens that
-// for all the types with this problem in bcachefs, removing the "packed" attribute and keeping
-// the "align" attribute results in a type with the correct ABI.
-//
-// This function applies that transformation to the following bcachefs types that need it:
-// - bkey
-// - bch_extent_crc32
-// - bch_extent_ptr
-// - btree_node
+// TODO: find a way to conditionally include arch-specific modifications when compiling for that
+// target arch. Regular conditional compilation won't work here since build scripts are always
+// compiled for the host arch, not the target arch, so that won't work when cross-compiling.
fn packed_and_align_fix(bindings: std::string::String) -> std::string::String {
bindings
.replace(
- "#[repr(C, packed(8))]\n#[repr(align(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bkey {",
- "#[repr(C, align(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bkey {",
+ "#[repr(C, packed(8))]\npub struct btree_node {",
+ "#[repr(C, align(8))]\npub struct btree_node {",
)
.replace(
- "#[repr(C, packed(8))]\n#[repr(align(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bch_extent_crc32 {",
- "#[repr(C, align(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bch_extent_crc32 {",
+ "#[repr(C, packed(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bch_extent_crc128 {",
+ "#[repr(C, align(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bch_extent_crc128 {",
)
.replace(
- "#[repr(C, packed(8))]\n#[repr(align(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bch_extent_ptr {",
- "#[repr(C, align(8))]\n#[derive(Debug, Default, Copy, Clone)]\npub struct bch_extent_ptr {",
+ "#[repr(C, packed(8))]\npub struct jset {",
+ "#[repr(C, align(8))]\npub struct jset {",
)
.replace(
- "#[repr(C, packed(8))]\npub struct btree_node {",
- "#[repr(C, align(8))]\npub struct btree_node {",
+ "#[repr(C, packed(8))]\npub struct btree_node_entry {",
+ "#[repr(C, align(8))]\npub struct btree_node_entry {",
+ )
+ .replace(
+ "#[repr(C, packed(8))]\npub struct bch_sb {",
+ "#[repr(C, align(8))]\npub struct bch_sb {",
)
}