GenEx: Limit TARGET_PROPERTY transitive closure optimization to subgraphs

Fixes: #25728

Source/cmGeneratorExpressionDAGChecker.cxx

@@ -24,7 +24,7 @@ cmGeneratorExpressionDAGChecker::cmGeneratorExpressionDAGChecker(
   std::string const& contextConfig)
   : cmGeneratorExpressionDAGChecker(cmListFileBacktrace(), target,
                                     std::move(property), content, parent,
-                                    contextLG, contextConfig)
+                                    contextLG, contextConfig, INHERIT)
 {
 }
 
@@ -33,8 +33,20 @@ cmGeneratorExpressionDAGChecker::cmGeneratorExpressionDAGChecker(
   std::string property, const GeneratorExpressionContent* content,
   cmGeneratorExpressionDAGChecker* parent, cmLocalGenerator const* contextLG,
   std::string const& contextConfig)
+  : cmGeneratorExpressionDAGChecker(std::move(backtrace), target,
+                                    std::move(property), content, parent,
+                                    contextLG, contextConfig, INHERIT)
+{
+}
+
+cmGeneratorExpressionDAGChecker::cmGeneratorExpressionDAGChecker(
+  cmListFileBacktrace backtrace, cmGeneratorTarget const* target,
+  std::string property, const GeneratorExpressionContent* content,
+  cmGeneratorExpressionDAGChecker* parent, cmLocalGenerator const* contextLG,
+  std::string const& contextConfig, TransitiveClosure closure)
   : Parent(parent)
   , Top(parent ? parent->Top : this)
+  , Closure((closure == SUBGRAPH || !parent) ? this : parent->Closure)
   , Target(target)
   , Property(std::move(property))
   , Content(content)
@@ -53,16 +65,16 @@ cmGeneratorExpressionDAGChecker::cmGeneratorExpressionDAGChecker(
   this->CheckResult = this->CheckGraph();
 
   if (this->CheckResult == DAG && this->EvaluatingTransitiveProperty()) {
-    const auto* top = this->Top;
-    auto it = top->Seen.find(this->Target);
-    if (it != top->Seen.end()) {
+    const auto* transitiveClosure = this->Closure;
+    auto it = transitiveClosure->Seen.find(this->Target);
+    if (it != transitiveClosure->Seen.end()) {
       const std::set<std::string>& propSet = it->second;
       if (propSet.find(this->Property) != propSet.end()) {
         this->CheckResult = ALREADY_SEEN;
         return;
       }
     }
-    top->Seen[this->Target].insert(this->Property);
+    transitiveClosure->Seen[this->Target].insert(this->Property);
   }
 }
 

Source/cmGeneratorExpressionDAGChecker.h

@@ -17,6 +17,17 @@ class cmLocalGenerator;
 
 struct cmGeneratorExpressionDAGChecker
 {
+  enum TransitiveClosure
+  {
+    INHERIT,
+    SUBGRAPH,
+  };
+
+  cmGeneratorExpressionDAGChecker(
+    cmListFileBacktrace backtrace, cmGeneratorTarget const* target,
+    std::string property, const GeneratorExpressionContent* content,
+    cmGeneratorExpressionDAGChecker* parent, cmLocalGenerator const* contextLG,
+    std::string const& contextConfig, TransitiveClosure closure);
   cmGeneratorExpressionDAGChecker(cmListFileBacktrace backtrace,
                                   cmGeneratorTarget const* target,
                                   std::string property,
@@ -76,6 +87,7 @@ private:
 
   const cmGeneratorExpressionDAGChecker* const Parent;
   const cmGeneratorExpressionDAGChecker* const Top;
+  const cmGeneratorExpressionDAGChecker* const Closure;
   cmGeneratorTarget const* Target;
   const std::string Property;
   mutable std::map<cmGeneratorTarget const*, std::set<std::string>> Seen;

Source/cmGeneratorExpressionNode.cxx

@@ -2983,8 +2983,9 @@ static const struct TargetPropertyNode : public cmGeneratorExpressionNode
 
     if (isInterfaceProperty) {
       return cmGeneratorExpression::StripEmptyListElements(
-        target->EvaluateInterfaceProperty(propertyName, context,
-                                          dagCheckerParent, usage));
+        target->EvaluateInterfaceProperty(
+          propertyName, context, dagCheckerParent, usage,
+          cmGeneratorTarget::TransitiveClosure::Subgraph));
     }
 
     cmGeneratorExpressionDAGChecker dagChecker(

Source/cmGeneratorTarget.h

@@ -918,11 +918,23 @@ public:
                             const std::string& report,
                             const std::string& compatibilityType) const;
 
+  /** Configures TransitiveClosureOptimization. Re-evaluation of a
+      transitive property will only be optimized within a subgraph. */
+  enum class TransitiveClosure
+  {
+    Inherit,  // node is in the same subgraph as its' parent
+    Subgraph, // the current node spans a new subgraph
+  };
+
   class TargetPropertyEntry;
 
   std::string EvaluateInterfaceProperty(
     std::string const& prop, cmGeneratorExpressionContext* context,
     cmGeneratorExpressionDAGChecker* dagCheckerParent, UseTo usage) const;
+  std::string EvaluateInterfaceProperty(
+    std::string const& prop, cmGeneratorExpressionContext* context,
+    cmGeneratorExpressionDAGChecker* dagCheckerParent, UseTo usage,
+    TransitiveClosure closure) const;
 
   struct TransitiveProperty
   {

Source/cmGeneratorTarget_TransitiveProperty.cxx

@@ -98,6 +98,15 @@ bool cmGeneratorTarget::MaybeHaveInterfaceProperty(
 std::string cmGeneratorTarget::EvaluateInterfaceProperty(
   std::string const& prop, cmGeneratorExpressionContext* context,
   cmGeneratorExpressionDAGChecker* dagCheckerParent, UseTo usage) const
+{
+  return EvaluateInterfaceProperty(prop, context, dagCheckerParent, usage,
+                                   TransitiveClosure::Inherit);
+}
+
+std::string cmGeneratorTarget::EvaluateInterfaceProperty(
+  std::string const& prop, cmGeneratorExpressionContext* context,
+  cmGeneratorExpressionDAGChecker* dagCheckerParent, UseTo usage,
+  TransitiveClosure closure) const
 {
   std::string result;
 
@@ -106,12 +115,15 @@ std::string cmGeneratorTarget::EvaluateInterfaceProperty(
     return result;
   }
 
+  auto const dagClosure = closure == TransitiveClosure::Inherit
+    ? cmGeneratorExpressionDAGChecker::INHERIT
+    : cmGeneratorExpressionDAGChecker::SUBGRAPH;
   // Evaluate $<TARGET_PROPERTY:this,prop> as if it were compiled.  This is
   // a subset of TargetPropertyNode::Evaluate without stringify/parse steps
   // but sufficient for transitive interface properties.
   cmGeneratorExpressionDAGChecker dagChecker(
     context->Backtrace, this, prop, nullptr, dagCheckerParent,
-    this->LocalGenerator, context->Config);
+    this->LocalGenerator, context->Config, dagClosure);
   switch (dagChecker.Check()) {
     case cmGeneratorExpressionDAGChecker::SELF_REFERENCE:
       dagChecker.ReportError(