1 files changed, 113 insertions, 0 deletions
diff --git a/src/codegen/helpers.rs b/src/codegen/helpers.rs
new file mode 100644
index 00000000..e2fc1120
--- /dev/null
+++ b/src/codegen/helpers.rs
@@ -0,0 +1,113 @@
+/// Helpers for code generation that don't need macro expansion.
+
+use aster;
+use ir::layout::Layout;
+use syntax::ast;
+use syntax::codemap::respan;
+use syntax::ptr::P;
+
+
+pub mod attributes {
+    use aster;
+    use syntax::ast;
+
+    pub fn repr(which: &str) -> ast::Attribute {
+        aster::AstBuilder::new().attr().list("repr").words(&[which]).build()
+    }
+
+    pub fn repr_list(which_ones: &[&str]) -> ast::Attribute {
+        aster::AstBuilder::new().attr().list("repr").words(which_ones).build()
+    }
+
+    pub fn derives(which_ones: &[&str]) -> ast::Attribute {
+        aster::AstBuilder::new().attr().list("derive").words(which_ones).build()
+    }
+
+    pub fn inline() -> ast::Attribute {
+        aster::AstBuilder::new().attr().word("inline")
+    }
+
+    pub fn doc(comment: &str) -> ast::Attribute {
+        aster::AstBuilder::new().attr().doc(comment)
+    }
+
+    pub fn link_name(name: &str) -> ast::Attribute {
+        aster::AstBuilder::new().attr().name_value("link_name").str(name)
+    }
+}
+
+/// Generates a proper type for a field or type with a given `Layout`, that is,
+/// a type with the correct size and alignment restrictions.
+pub struct BlobTyBuilder {
+    layout: Layout,
+}
+
+impl BlobTyBuilder {
+    pub fn new(layout: Layout) -> Self {
+        BlobTyBuilder {
+            layout: layout,
+        }
+    }
+
+    pub fn build(self) -> P<ast::Ty> {
+        use std::cmp;
+
+        let ty_name = match self.layout.align {
+            8 => "u64",
+            4 => "u32",
+            2 => "u16",
+            1 | _ => "u8",
+        };
+        let data_len = if ty_name == "u8" {
+            self.layout.size
+        } else {
+            self.layout.size / cmp::max(self.layout.align, 1)
+        };
+
+        let inner_ty = aster::AstBuilder::new().ty().path().id(ty_name).build();
+        if data_len == 1 {
+            inner_ty
+        } else {
+            ArrayTyBuilder::new().with_len(data_len).build(inner_ty)
+        }
+    }
+}
+
+pub struct ArrayTyBuilder {
+    len: usize,
+}
+
+impl ArrayTyBuilder {
+    pub fn new() -> Self {
+        ArrayTyBuilder {
+            len: 0,
+        }
+    }
+
+    pub fn with_len(mut self, len: usize) -> Self {
+        self.len = len;
+        self
+    }
+
+    pub fn build(self, ty: P<ast::Ty>) -> P<ast::Ty> {
+        use syntax::codemap::DUMMY_SP;
+        let size =
+            ast::LitKind::Int(self.len as u64,
+                              ast::LitIntType::Unsigned(ast::UintTy::Us));
+        let size = ast::ExprKind::Lit(P(respan(DUMMY_SP, size)));
+        let array_kind = ast::TyKind::FixedLengthVec(ty,
+            P(ast::Expr {
+                id: ast::DUMMY_NODE_ID,
+                node: size,
+                span: DUMMY_SP,
+                attrs: ast::ThinVec::new(),
+            })
+        );
+
+        P(ast::Ty {
+            id: ast::DUMMY_NODE_ID,
+            node: array_kind,
+            span: DUMMY_SP,
+        })
+    }
+}