tamer: {ir::asg=>ld::xmle}::section

Sections, as written, are specific to xmle files.

I think the intent originally was to have this be more generic, but that
doesn't really make sense.

By explicitly coupling it with `xmle` files, that will allow us to turn this
into a proper lowering operation with its own validations that will allow
`xmle::xir` to do its job without having to validate anything itself.

tamer/src/ir/asg/base.rs

@@ -27,7 +27,7 @@ use super::ident::IdentKind;
 use super::object::{
     FragmentText, IdentObjectData, IdentObjectState, Source, TransitionResult,
 };
-use super::Sections;
+use crate::ld::xmle::Sections;
 use crate::sym::{GlobalSymbolResolve, SymbolId};
 use petgraph::graph::{DiGraph, Graph, NodeIndex};
 use petgraph::visit::DfsPostOrder;

tamer/src/ir/asg/graph.rs

@@ -24,7 +24,7 @@ use super::object::{
     FragmentText, IdentObjectData, IdentObjectState, Source, TransitionError,
     UnresolvedError,
 };
-use super::Sections;
+use crate::ld::xmle::Sections;
 use crate::sym::SymbolId;
 use petgraph::graph::NodeIndex;
 use std::fmt::Debug;

tamer/src/ir/asg/mod.rs

@@ -194,7 +194,6 @@ mod base;
 mod graph;
 mod ident;
 mod object;
-mod section;
 
 pub use graph::{
     Asg, AsgError, AsgResult, IndexType, ObjectRef, SortableAsg,
@@ -205,7 +204,6 @@ pub use object::{
     FragmentText, IdentObject, IdentObjectData, IdentObjectState, Source,
     TransitionError, TransitionResult, UnresolvedError,
 };
-pub use section::{Section, SectionIter, Sections, SectionsIter};
 
 /// Default concrete ASG implementation.
 pub type DefaultAsg<O, Ix = crate::global::ProgSymSize> = base::BaseAsg<O, Ix>;

tamer/src/ld/poc.rs

@@ -20,13 +20,13 @@
 //! **This contains the remaining portions of the proof-of-concept linker.**
 //! It is feature-complete and just needs final refactoring.
 
-use super::xmle::xir::lower_iter;
+use super::xmle::{xir::lower_iter, Sections};
 use crate::fs::{
     Filesystem, FsCanonicalizer, PathFile, VisitOnceFile, VisitOnceFilesystem,
 };
 use crate::global;
 use crate::ir::asg::{
-    Asg, DefaultAsg, IdentObject, IdentObjectData, Sections, SortableAsg,
+    Asg, DefaultAsg, IdentObject, IdentObjectData, SortableAsg,
     SortableAsgError,
 };
 use crate::ir::xir::writer::XmlWriter;

tamer/src/ld/xmle/mod.rs

@@ -69,4 +69,7 @@
 //! </package>
 //! ```
 
+mod section;
 pub mod xir;
+
+pub use section::{Section, SectionIter, Sections, SectionsIter};

tamer/src/ld/xmle/section.rs

@@ -17,14 +17,15 @@
 //  You should have received a copy of the GNU General Public License
 //  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-//! Ordered sections of ASG object references.
+//! Sections of a linked [`xmle`](super) object file.
 //!
-//! These sections are the result of an ordering operation from
-//!   [`SortableAsg::sort`].
+//! These sections are the result of [`SortableAsg::sort`],
+//!   which places the relocatable object code fragments in the order
+//!   necessary for execution.
 //!
-//! [`SortableAsg::sort`]: super::SortableAsg::sort
+//! [`SortableAsg::sort`]: crate::ir::asg::SortableAsg::sort
 
-use super::IdentObjectData;
+use crate::ir::asg::IdentObjectData;
 use crate::sym::SymbolId;
 use fxhash::FxHashSet;
 use std::collections::hash_set;

tamer/src/ld/xmle/xir.rs

@@ -29,11 +29,10 @@
 //!   which can then use [`XmlWriter`](crate::ir::xir::writer::XmlWriter)
 //!   for writing.
 
+use super::{Sections, SectionsIter};
 use crate::{
     ir::{
-        asg::{
-            IdentKind, IdentObject, IdentObjectData, Sections, SectionsIter,
-        },
+        asg::{IdentKind, IdentObject, IdentObjectData},
         xir::{
             iter::{elem_wrap, ElemWrapIter},
             AttrValue, QName, Text, Token,