Multi-Ninja: Fix PCHs for Visual C++

Fixes: #20711

Help/prop_sf/OBJECT_OUTPUTS.rst

@@ -7,3 +7,6 @@ Additional outputs created by compilation of this source file.  If any
 of these outputs is missing the object will be recompiled.  This is
 supported only on the :generator:`Ninja` and :ref:`Makefile Generators`
 and will be ignored on other generators.
+
+This property supports
+:manual:`generator expressions <cmake-generator-expressions(7)>`.

Help/release/dev/genex-OBJECT_OUTPUTS.rst

@@ -0,0 +1,4 @@
+genex-OBJECT_OUTPUTS
+--------------------
+
+* :prop_sf:`OBJECT_OUTPUTS` now support :manual:`generator expressions <cmake-generator-expressions(7)>`.

Source/cmGeneratorTarget.cxx

@@ -3864,6 +3864,10 @@ std::string cmGeneratorTarget::GetPchFileObject(const std::string& config,
       pchSource, false, cmSourceFileLocationKind::Known);
 
     filename = cmStrCat(this->ObjectDirectory, this->GetObjectName(pchSf));
+    if (this->GetGlobalGenerator()->IsMultiConfig()) {
+      cmSystemTools::ReplaceString(
+        filename, this->GetGlobalGenerator()->GetCMakeCFGIntDir(), config);
+    }
   }
   return inserted.first->second;
 }

Source/cmLocalGenerator.cxx

@@ -2633,7 +2633,9 @@ void cmLocalGenerator::AddPchDependencies(cmGeneratorTarget* target)
           // Exclude the pch files from linking
           if (this->Makefile->IsOn("CMAKE_LINK_PCH")) {
             if (!ReuseFrom) {
-              pch_sf->SetProperty("OBJECT_OUTPUTS", pchFile.c_str());
+              pch_sf->AppendProperty(
+                "OBJECT_OUTPUTS",
+                cmStrCat("$<$<CONFIG:", config, ">:", pchFile, ">"));
             } else {
               auto reuseTarget =
                 this->GlobalGenerator->FindGeneratorTarget(*ReuseFrom);

Source/cmMakefileTargetGenerator.cxx

@@ -895,9 +895,14 @@ void cmMakefileTargetGenerator::WriteObjectRuleFiles(
   // Check for extra outputs created by the compilation.
   std::vector<std::string> outputs(1, relativeObj);
   if (cmProp extra_outputs_str = source.GetProperty("OBJECT_OUTPUTS")) {
-    // Register these as extra files to clean.
-    cmExpandList(*extra_outputs_str, outputs);
-    this->CleanFiles.insert(outputs.begin() + 1, outputs.end());
+    std::string evaluated_outputs = cmGeneratorExpression::Evaluate(
+      *extra_outputs_str, this->LocalGenerator, config);
+
+    if (!evaluated_outputs.empty()) {
+      // Register these as extra files to clean.
+      cmExpandList(evaluated_outputs, outputs);
+      this->CleanFiles.insert(outputs.begin() + 1, outputs.end());
+    }
   }
 
   // Write the rule.

Source/cmNinjaTargetGenerator.cxx

@@ -1266,14 +1266,19 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatement(
   }
 
   if (cmProp objectOutputs = source->GetProperty("OBJECT_OUTPUTS")) {
-    cmNinjaBuild build("phony");
-    build.Comment = "Additional output files.";
-    build.Outputs = cmExpandedList(*objectOutputs);
-    std::transform(build.Outputs.begin(), build.Outputs.end(),
-                   build.Outputs.begin(), MapToNinjaPath());
-    build.ExplicitDeps = objBuild.Outputs;
-    this->GetGlobalGenerator()->WriteBuild(this->GetImplFileStream(fileConfig),
-                                           build);
+    std::string evaluatedObjectOutputs = cmGeneratorExpression::Evaluate(
+      *objectOutputs, this->LocalGenerator, config);
+
+    if (!evaluatedObjectOutputs.empty()) {
+      cmNinjaBuild build("phony");
+      build.Comment = "Additional output files.";
+      build.Outputs = cmExpandedList(evaluatedObjectOutputs);
+      std::transform(build.Outputs.begin(), build.Outputs.end(),
+                     build.Outputs.begin(), MapToNinjaPath());
+      build.ExplicitDeps = objBuild.Outputs;
+      this->GetGlobalGenerator()->WriteBuild(
+        this->GetImplFileStream(fileConfig), build);
+    }
   }
 }