From 878d154322504b4bd912247a350471869ad62e3a Mon Sep 17 00:00:00 2001
From: Eduard Voronkin <edward.voronkin@gmail.com>
Date: Mon, 10 Nov 2025 14:47:14 -0800
Subject: [PATCH] FASTBuild: fix multi-language PCHs

Fixes: #27371
---
 Source/cmFastbuildNormalTargetGenerator.cxx | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/Source/cmFastbuildNormalTargetGenerator.cxx b/Source/cmFastbuildNormalTargetGenerator.cxx
index 0ee97d7aee..efeabaeb60 100644
--- a/Source/cmFastbuildNormalTargetGenerator.cxx
+++ b/Source/cmFastbuildNormalTargetGenerator.cxx
@@ -1499,11 +1499,13 @@ void cmFastbuildNormalTargetGenerator::GenerateObjects(FastbuildTarget& target)
   objects.reserve(nodesPermutations.size());
   for (auto& val : nodesPermutations) {
     auto& node = val.second;
-    objects.emplace_back(std::move(node));
-    if (!objects.back().PCHInputFile.empty()) {
+    if (!node.PCHInputFile.empty()) {
       // Node that produces PCH should be the first one, since other nodes
       // might reuse this PCH.
-      std::swap(*objects.begin(), objects.back());
+      // Note: we might have several such nodes for different languages.
+      objects.insert(objects.begin(), std::move(node));
+    } else {
+      objects.emplace_back(std::move(node));
     }
   }
   if (useUnity) {