Auto merge of #127602 - onur-ozkan:calling-order, r=Kobzol

maintain the given order on step execution

Previously step execution disregarded the CLI order and this change executes the given steps in the order specified on CLI.

For example, running `x $kind a b c` will execute `$kind` step for `a`, then `b`, then `c` crates in the specified order.

Fixes #126165
cc `@matthiaskrgr`

src/bootstrap/src/core/builder.rs

@@ -473,9 +473,41 @@ fn run(v: &[StepDescription], builder: &Builder<'_>, paths: &[PathBuf]) {
             return;
         }
 
-        // Handle all PathSets.
+        let mut path_lookup: Vec<(PathBuf, bool)> =
+            paths.clone().into_iter().map(|p| (p, false)).collect();
+
+        // List of `(usize, &StepDescription, Vec<PathSet>)` where `usize` is the closest index of a path
+        // compared to the given CLI paths. So we can respect to the CLI order by using this value to sort
+        // the steps.
+        let mut steps_to_run = vec![];
+
         for (desc, should_run) in v.iter().zip(&should_runs) {
             let pathsets = should_run.pathset_for_paths_removing_matches(&mut paths, desc.kind);
+
+            // This value is used for sorting the step execution order.
+            // By default, `usize::MAX` is used as the index for steps to assign them the lowest priority.
+            //
+            // If we resolve the step's path from the given CLI input, this value will be updated with
+            // the step's actual index.
+            let mut closest_index = usize::MAX;
+
+            // Find the closest index from the original list of paths given by the CLI input.
+            for (index, (path, is_used)) in path_lookup.iter_mut().enumerate() {
+                if !*is_used && !paths.contains(path) {
+                    closest_index = index;
+                    *is_used = true;
+                    break;
+                }
+            }
+
+            steps_to_run.push((closest_index, desc, pathsets));
+        }
+
+        // Sort the steps before running them to respect the CLI order.
+        steps_to_run.sort_by_key(|(index, _, _)| *index);
+
+        // Handle all PathSets.
+        for (_index, desc, pathsets) in steps_to_run {
             if !pathsets.is_empty() {
                 desc.maybe_run(builder, pathsets);
             }