From 9185ddb019259883db1d5c2625f4ecb42d3aa77b Mon Sep 17 00:00:00 2001
From: Weihang Lo <me@weihanglo.tw>
Date: Fri, 24 May 2024 15:20:20 -0400
Subject: [PATCH] bootstrap: support target specific config overrides

---
 src/bootstrap/src/core/config/config.rs | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 19119a073c5f..7eb42ad32f53 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -644,7 +644,20 @@ impl Merge for TomlConfig {
         do_merge(&mut self.llvm, llvm, replace);
         do_merge(&mut self.rust, rust, replace);
         do_merge(&mut self.dist, dist, replace);
-        assert!(target.is_none(), "merging target-specific config is not currently supported");
+
+        match (self.target.as_mut(), target) {
+            (_, None) => {}
+            (None, Some(target)) => self.target = Some(target),
+            (Some(original_target), Some(new_target)) => {
+                for (triple, new) in new_target {
+                    if let Some(original) = original_target.get_mut(&triple) {
+                        original.merge(new, replace);
+                    } else {
+                        original_target.insert(triple, new);
+                    }
+                }
+            }
+        }
     }
 }