Merge branch 'backport-3.16-pch-fix-bad-ClearSourcesCache'

2 files changed, 17 insertions, 3 deletions

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 5828651..94a795e 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -3555,8 +3555,6 @@ std::string cmGeneratorTarget::GetPchFileObject(const std::string& config,
     }
     std::string& filename = inserted.first->second;
 
-    this->AddSource(pchSource, true);
-
     auto pchSf = this->Makefile->GetOrCreateSource(
       pchSource, false, cmSourceFileLocationKind::Known);
 
diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index 6a2d4c7..238097d 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -1609,7 +1609,23 @@ bool cmGlobalGenerator::AddAutomaticSources()
         continue;
       }
       lg->AddUnityBuild(gt.get());
-      lg->AddPchDependencies(gt.get());
+      // Targets that re-use a PCH are handled below.
+      if (!gt->GetProperty("PRECOMPILE_HEADERS_REUSE_FROM")) {
+        lg->AddPchDependencies(gt.get());
+      }
+    }
+  }
+  for (const auto& lg : this->LocalGenerators) {
+    for (const auto& gt : lg->GetGeneratorTargets()) {
+      if (gt->GetType() == cmStateEnums::INTERFACE_LIBRARY ||
+          gt->GetType() == cmStateEnums::UTILITY ||
+          gt->GetType() == cmStateEnums::GLOBAL_TARGET) {
+        continue;
+      }
+      // Handle targets that re-use a PCH from an above-handled target.
+      if (gt->GetProperty("PRECOMPILE_HEADERS_REUSE_FROM")) {
+        lg->AddPchDependencies(gt.get());
+      }
     }
   }
   // The above transformations may have changed the classification of sources.