Move alignment config from declare_data to define_data

cranelift/module/src/data_context.rs

@@ -50,6 +50,8 @@ pub struct DataDescription {
     pub data_relocs: Vec<(CodeOffset, ir::GlobalValue, Addend)>,
     /// Object file section
     pub custom_segment_section: Option<(String, String)>,
+    /// Alignment
+    pub align: Option<u64>,
 }
 
 /// This is to data objects what cranelift_codegen::Context is to functions.
@@ -68,6 +70,7 @@ impl DataContext {
                 function_relocs: vec![],
                 data_relocs: vec![],
                 custom_segment_section: None,
+                align: None,
             },
         }
     }
@@ -79,6 +82,8 @@ impl DataContext {
         self.description.data_decls.clear();
         self.description.function_relocs.clear();
         self.description.data_relocs.clear();
+        self.description.custom_segment_section = None;
+        self.description.align = None;
     }
 
     /// Define a zero-initialized object with the given size.
@@ -100,6 +105,12 @@ impl DataContext {
         self.description.custom_segment_section = Some((seg.to_owned(), sec.to_owned()))
     }
 
+    /// Set the alignment for data. The alignment must be a power of two.
+    pub fn set_align(&mut self, align: u64) {
+        assert!(align.is_power_of_two());
+        self.description.align = Some(align);
+    }
+
     /// Declare an external function import.
     ///
     /// Users of the `Module` API generally should call