Merge topic 'make-GENERATED-visible-from-any-scope'

573d51201a GENERATED prop: Set CMP0118 to NEW for some (unrelated) tests
6624b65b3f GENERATED prop: Add implementation for policy CMP0118 being set to NEW
b14fe704f8 GENERATED prop: Simplify determining the language of a source file
ca4ce458a3 GENERATED prop: Check CMP0118 policy and warn in certain situations
0eb30f175e GENERATED prop: Introducing policy CMP0118 and its documentation
78c8d95605 GENERATED prop: Add some tests before introducing changes with CMP0118
e01527619f Simplify code by calling a function directly instead of duplicating it
75cb8615e9 Fix typo in function name

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !5308

14 files changed, 241 insertions, 54 deletions

diff --git a/Source/cmCPluginAPI.cxx b/Source/cmCPluginAPI.cxx
index 968fa54..9e3582c 100644
--- a/Source/cmCPluginAPI.cxx
+++ b/Source/cmCPluginAPI.cxx
@@ -550,6 +550,11 @@ void* CCONV cmAddSource(void* arg, void* arg2)
   // Create the real cmSourceFile instance and copy over saved information.
   cmSourceFile* rsf = mf->GetOrCreateSource(osf->FullPath);
   rsf->SetProperties(osf->Properties);
+  // In case the properties contain the GENERATED property,
+  // mark the real cmSourceFile as generated.
+  if (rsf->GetIsGenerated()) {
+    rsf->MarkAsGenerated();
+  }
   for (std::string const& d : osf->Depends) {
     rsf->AddDepend(d);
   }
diff --git a/Source/cmGeneratorExpressionEvaluationFile.cxx b/Source/cmGeneratorExpressionEvaluationFile.cxx
index 9e5023d..3c17b54 100644
--- a/Source/cmGeneratorExpressionEvaluationFile.cxx
+++ b/Source/cmGeneratorExpressionEvaluationFile.cxx
@@ -15,7 +15,6 @@
 #include "cmMakefile.h"
 #include "cmMessageType.h"
 #include "cmSourceFile.h"
-#include "cmSourceFileLocationKind.h"
 #include "cmSystemTools.h"
 
 cmGeneratorExpressionEvaluationFile::cmGeneratorExpressionEvaluationFile(
@@ -99,11 +98,7 @@ void cmGeneratorExpressionEvaluationFile::CreateOutputFile(
 
   for (std::string const& le : enabledLanguages) {
     std::string const name = this->GetOutputFileName(lg, target, config, le);
-    cmSourceFile* sf = lg->GetMakefile()->GetOrCreateSource(
-      name, false, cmSourceFileLocationKind::Known);
-    // Tell TraceDependencies that the file is not expected to exist
-    // on disk yet.  We generate it after that runs.
-    sf->SetProperty("GENERATED", "1");
+    cmSourceFile* sf = lg->GetMakefile()->GetOrCreateGeneratedSource(name);
 
     // Tell the build system generators that there is no build rule
     // to generate the file.
diff --git a/Source/cmGetPropertyCommand.cxx b/Source/cmGetPropertyCommand.cxx
index e755399..cb657f9 100644
--- a/Source/cmGetPropertyCommand.cxx
+++ b/Source/cmGetPropertyCommand.cxx
@@ -172,7 +172,7 @@ bool cmGetPropertyCommand(std::vector<std::string> const& args,
 
   std::vector<cmMakefile*> source_file_directory_makefiles;
   bool file_scopes_handled =
-    SetPropertyCommand::HandleAndValidateSourceFileDirectortoryScopes(
+    SetPropertyCommand::HandleAndValidateSourceFileDirectoryScopes(
       status, source_file_directory_option_enabled,
       source_file_target_option_enabled, source_file_directories,
       source_file_target_directories, source_file_directory_makefiles);
diff --git a/Source/cmGetSourceFilePropertyCommand.cxx b/Source/cmGetSourceFilePropertyCommand.cxx
index 212a968..5301b66 100644
--- a/Source/cmGetSourceFilePropertyCommand.cxx
+++ b/Source/cmGetSourceFilePropertyCommand.cxx
@@ -35,7 +35,7 @@ bool cmGetSourceFilePropertyCommand(std::vector<std::string> const& args,
 
   std::vector<cmMakefile*> source_file_directory_makefiles;
   bool file_scopes_handled =
-    SetPropertyCommand::HandleAndValidateSourceFileDirectortoryScopes(
+    SetPropertyCommand::HandleAndValidateSourceFileDirectoryScopes(
       status, source_file_directory_option_enabled,
       source_file_target_option_enabled, source_file_directories,
       source_file_target_directories, source_file_directory_makefiles);
diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index 9d84313..63aaf27 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -1821,6 +1821,7 @@ void cmGlobalGenerator::ClearGeneratorMembers()
   this->RuleHashes.clear();
   this->DirectoryContentMap.clear();
   this->BinaryDirectories.clear();
+  this->GeneratedFiles.clear();
 }
 
 void cmGlobalGenerator::ComputeTargetObjectDirectory(
@@ -2146,6 +2147,16 @@ void cmGlobalGenerator::AddInstallComponent(const std::string& component)
   }
 }
 
+void cmGlobalGenerator::MarkAsGeneratedFile(const std::string& filepath)
+{
+  this->GeneratedFiles.insert(filepath);
+}
+
+bool cmGlobalGenerator::IsGeneratedFile(const std::string& filepath)
+{
+  return this->GeneratedFiles.find(filepath) != this->GeneratedFiles.end();
+}
+
 void cmGlobalGenerator::EnableInstallTarget()
 {
   this->InstallTargetEnabled = true;
diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index c1813d0..69373bd 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -11,6 +11,7 @@
 #include <set>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -290,6 +291,11 @@ public:
 
   void AddInstallComponent(const std::string& component);
 
+  /** Mark the (absolute path to a) file as generated.  */
+  void MarkAsGeneratedFile(const std::string& filepath);
+  /** Determine if the absolute filepath belongs to a generated file.  */
+  bool IsGeneratedFile(const std::string& filepath);
+
   const std::set<std::string>* GetInstallComponents() const
   {
     return &this->InstallComponents;
@@ -733,6 +739,8 @@ private:
 
   std::map<std::string, std::string> RealPaths;
 
+  std::unordered_set<std::string> GeneratedFiles;
+
 #if !defined(CMAKE_BOOTSTRAP)
   // Pool of file locks
   cmFileLockPool FileLockPool;
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 50a7d27..4e93785 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -3406,11 +3406,7 @@ cmSourceFile* cmMakefile::CreateSource(const std::string& sourceName,
                                        bool generated,
                                        cmSourceFileLocationKind kind)
 {
-  auto sf = cm::make_unique<cmSourceFile>(this, sourceName, kind);
-  if (generated) {
-    sf->SetProperty("GENERATED", "1");
-  }
-
+  auto sf = cm::make_unique<cmSourceFile>(this, sourceName, generated, kind);
   auto name =
     this->GetCMakeInstance()->StripExtension(sf->GetLocation().GetName());
 #if defined(_WIN32) || defined(__APPLE__)
@@ -3442,7 +3438,7 @@ cmSourceFile* cmMakefile::GetOrCreateGeneratedSource(
 {
   cmSourceFile* sf =
     this->GetOrCreateSource(sourceName, true, cmSourceFileLocationKind::Known);
-  sf->SetProperty("GENERATED", "1");
+  sf->MarkAsGenerated(); // In case we did not create the source file.
   return sf;
 }
 
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index 30cd4b7..646e226 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -348,7 +348,11 @@ class cmMakefile;
          20, 0, cmPolicies::WARN)                                             \
   SELECT(POLICY, CMP0117,                                                     \
          "MSVC RTTI flag /GR is not added to CMAKE_CXX_FLAGS by default.", 3, \
-         20, 0, cmPolicies::WARN)
+         20, 0, cmPolicies::WARN)                                             \
+  SELECT(                                                                     \
+    POLICY, CMP0118,                                                          \
+    "The GENERATED source file property is now visible in all directories.",  \
+    3, 20, 0, cmPolicies::WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
 #define CM_FOR_EACH_POLICY_ID(POLICY)                                         \
diff --git a/Source/cmQtAutoGenInitializer.cxx b/Source/cmQtAutoGenInitializer.cxx
index f2696a6..f27b788 100644
--- a/Source/cmQtAutoGenInitializer.cxx
+++ b/Source/cmQtAutoGenInitializer.cxx
@@ -1624,7 +1624,7 @@ cmSourceFile* cmQtAutoGenInitializer::RegisterGeneratedSource(
   std::string const& filename)
 {
   cmSourceFile* gFile = this->Makefile->GetOrCreateSource(filename, true);
-  gFile->SetProperty("GENERATED", "1");
+  gFile->MarkAsGenerated();
   gFile->SetProperty("SKIP_AUTOGEN", "1");
   return gFile;
 }
diff --git a/Source/cmSetPropertyCommand.cxx b/Source/cmSetPropertyCommand.cxx
index df6a38a..970564d 100644
--- a/Source/cmSetPropertyCommand.cxx
+++ b/Source/cmSetPropertyCommand.cxx
@@ -10,9 +10,12 @@
 #include "cmGlobalGenerator.h"
 #include "cmInstalledFile.h"
 #include "cmMakefile.h"
+#include "cmMessageType.h"
+#include "cmPolicies.h"
 #include "cmProperty.h"
 #include "cmRange.h"
 #include "cmSourceFile.h"
+#include "cmSourceFileLocation.h"
 #include "cmState.h"
 #include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
@@ -157,7 +160,7 @@ bool HandleSourceFileDirectoryScopeValidation(
   return true;
 }
 
-bool HandleAndValidateSourceFileDirectortoryScopes(
+bool HandleAndValidateSourceFileDirectoryScopes(
   cmExecutionStatus& status, bool source_file_directory_option_enabled,
   bool source_file_target_option_enabled,
   std::vector<std::string>& source_file_directories,
@@ -216,8 +219,92 @@ void MakeSourceFilePathsAbsoluteIfNeeded(
     source_files_absolute_paths.push_back(absolute_file_path);
   }
 }
+
+bool HandleAndValidateSourceFilePropertyGENERATED(
+  cmSourceFile* sf, std::string const& propertyValue, PropertyOp op)
+{
+  auto& mf = *sf->GetLocation().GetMakefile();
+  auto policyStatus = mf.GetPolicyStatus(cmPolicies::CMP0118);
+
+  const bool policyWARN = policyStatus == cmPolicies::WARN;
+  const bool policyNEW = policyStatus != cmPolicies::OLD && !policyWARN;
+
+  if (policyWARN) {
+    if (!cmIsOn(propertyValue) && !cmIsOff(propertyValue)) {
+      mf.IssueMessage(
+        MessageType::AUTHOR_WARNING,
+        cmStrCat(cmPolicies::GetPolicyWarning(cmPolicies::CMP0118),
+                 "\nAttempt to set property 'GENERATED' with the following "
+                 "non-boolean value (which will be interpreted as \"0\"):\n",
+                 propertyValue,
+                 "\nThat exact value will not be retrievable. A value of "
+                 "\"0\" will be returned instead.\n"
+                 "This will be an error under policy CMP0118.\n"));
+    }
+    if (cmIsOff(propertyValue)) {
+      mf.IssueMessage(
+        MessageType::AUTHOR_WARNING,
+        cmStrCat(cmPolicies::GetPolicyWarning(cmPolicies::CMP0118),
+                 "\nUnsetting property 'GENERATED' will not be allowed under "
+                 "policy CMP0118!\n"));
+    }
+    if (op == PropertyOp::Append || op == PropertyOp::AppendAsString) {
+      mf.IssueMessage(
+        MessageType::AUTHOR_WARNING,
+        cmStrCat(cmPolicies::GetPolicyWarning(cmPolicies::CMP0118),
+                 "\nAppending to property 'GENERATED' will not be allowed "
+                 "under policy CMP0118!\n"));
+    }
+  } else if (policyNEW) {
+    if (!cmIsOn(propertyValue) && !cmIsOff(propertyValue)) {
+      mf.IssueMessage(
+        MessageType::AUTHOR_ERROR,
+        cmStrCat(
+          "Policy CMP0118 is set to NEW and the following non-boolean value "
+          "given for property 'GENERATED' is therefore not allowed:\n",
+          propertyValue, "\nReplace it with a boolean value!\n"));
+      return true;
+    }
+    if (cmIsOff(propertyValue)) {
+      mf.IssueMessage(
+        MessageType::AUTHOR_ERROR,
+        "Unsetting the 'GENERATED' property is not allowed under CMP0118!\n");
+      return true;
+    }
+    if (op == PropertyOp::Append || op == PropertyOp::AppendAsString) {
+      mf.IssueMessage(MessageType::AUTHOR_ERROR,
+                      "Policy CMP0118 is set to NEW and appending to the "
+                      "'GENERATED' property is therefore not allowed. Only "
+                      "setting it to \"1\" is allowed!\n");
+      return true;
+    }
+  }
+
+  // Set property.
+  if (!policyNEW) {
+    // Do it the traditional way.
+    switch (op) {
+      case PropertyOp::Append:
+        sf->AppendProperty("GENERATED", propertyValue, false);
+        break;
+      case PropertyOp::AppendAsString:
+        sf->AppendProperty("GENERATED", propertyValue, true);
+        break;
+      case PropertyOp::Remove:
+        sf->SetProperty("GENERATED", nullptr);
+        break;
+      case PropertyOp::Set:
+        sf->SetProperty("GENERATED", propertyValue.c_str());
+        break;
+    }
+  } else {
+    sf->MarkAsGenerated();
+  }
+  return true;
 }
 
+} // END: namespace SetPropertyCommand
+
 bool cmSetPropertyCommand(std::vector<std::string> const& args,
                           cmExecutionStatus& status)
 {
@@ -324,7 +411,7 @@ bool cmSetPropertyCommand(std::vector<std::string> const& args,
 
   std::vector<cmMakefile*> source_file_directory_makefiles;
   bool file_scopes_handled =
-    SetPropertyCommand::HandleAndValidateSourceFileDirectortoryScopes(
+    SetPropertyCommand::HandleAndValidateSourceFileDirectoryScopes(
       status, source_file_directory_option_enabled,
       source_file_target_option_enabled, source_file_directories,
       source_file_target_directories, source_file_directory_makefiles);
@@ -367,7 +454,7 @@ bool cmSetPropertyCommand(std::vector<std::string> const& args,
   return true;
 }
 
-namespace {
+namespace /* anonymous */ {
 bool HandleGlobalMode(cmExecutionStatus& status,
                       const std::set<std::string>& names,
                       const std::string& propertyName,
@@ -525,6 +612,18 @@ bool HandleSource(cmSourceFile* sf, const std::string& propertyName,
                   const std::string& propertyValue, bool appendAsString,
                   bool appendMode, bool remove)
 {
+  // Special validation and handling of GENERATED flag?
+  if (propertyName == "GENERATED") {
+    SetPropertyCommand::PropertyOp op = (remove)
+      ? SetPropertyCommand::PropertyOp::Remove
+      : (appendAsString)
+        ? SetPropertyCommand::PropertyOp::AppendAsString
+        : (appendMode) ? SetPropertyCommand::PropertyOp::Append
+                       : SetPropertyCommand::PropertyOp::Set;
+    return SetPropertyCommand::HandleAndValidateSourceFilePropertyGENERATED(
+      sf, propertyValue, op);
+  }
+
   // Set or append the property.
   if (appendMode) {
     sf->AppendProperty(propertyName, propertyValue, appendAsString);
diff --git a/Source/cmSetPropertyCommand.h b/Source/cmSetPropertyCommand.h
index 89fdd9a..05c4873 100644
--- a/Source/cmSetPropertyCommand.h
+++ b/Source/cmSetPropertyCommand.h
@@ -9,6 +9,7 @@
 
 class cmMakefile;
 class cmExecutionStatus;
+class cmSourceFile;
 
 bool cmSetPropertyCommand(std::vector<std::string> const& args,
                           cmExecutionStatus& status);
@@ -25,7 +26,7 @@ bool HandleSourceFileDirectoryScopeValidation(
   std::vector<std::string>& source_file_directories,
   std::vector<std::string>& source_file_target_directories);
 
-bool HandleAndValidateSourceFileDirectortoryScopes(
+bool HandleAndValidateSourceFileDirectoryScopes(
   cmExecutionStatus& status, bool source_directories_option_encountered,
   bool source_target_directories_option_encountered,
   std::vector<std::string>& source_directories,
@@ -39,4 +40,16 @@ void MakeSourceFilePathsAbsoluteIfNeeded(
   std::vector<std::string>& source_files_absolute_paths,
   std::vector<std::string>::const_iterator files_it_begin,
   std::vector<std::string>::const_iterator files_it_end, bool needed);
+
+enum class PropertyOp
+{
+  Remove,
+  Set,
+  Append,
+  AppendAsString
+};
+
+bool HandleAndValidateSourceFilePropertyGENERATED(
+  cmSourceFile* sf, std::string const& propertyValue,
+  PropertyOp op = PropertyOp::Set);
 }
diff --git a/Source/cmSetSourceFilesPropertiesCommand.cxx b/Source/cmSetSourceFilesPropertiesCommand.cxx
index c1b0c28..742aa96 100644
--- a/Source/cmSetSourceFilesPropertiesCommand.cxx
+++ b/Source/cmSetSourceFilesPropertiesCommand.cxx
@@ -7,6 +7,7 @@
 
 #include <cm/string_view>
 #include <cmext/algorithm>
+#include <cmext/string_view>
 
 #include "cmExecutionStatus.h"
 #include "cmMakefile.h"
@@ -82,7 +83,7 @@ bool cmSetSourceFilesPropertiesCommand(std::vector<std::string> const& args,
   const auto props_begin = options_it;
 
   bool file_scopes_handled =
-    SetPropertyCommand::HandleAndValidateSourceFileDirectortoryScopes(
+    SetPropertyCommand::HandleAndValidateSourceFileDirectoryScopes(
       status, source_file_directory_option_enabled,
       source_file_target_option_enabled, source_file_directories,
       source_file_target_directories, source_file_directory_makefiles);
@@ -167,7 +168,13 @@ static bool RunCommandForScope(
     if (cmSourceFile* sf = mf->GetOrCreateSource(sfname)) {
       // loop through the props and set them
       for (auto k = propertyPairs.begin(); k != propertyPairs.end(); k += 2) {
-        sf->SetProperty(*k, (k + 1)->c_str());
+        // Special handling for GENERATED property?
+        if (*k == "GENERATED"_s) {
+          SetPropertyCommand::HandleAndValidateSourceFilePropertyGENERATED(
+            sf, *(k + 1));
+        } else {
+          sf->SetProperty(*k, (k + 1)->c_str());
+        }
       }
     }
   }
diff --git a/Source/cmSourceFile.cxx b/Source/cmSourceFile.cxx
index 39074a5..9d9a7c3 100644
--- a/Source/cmSourceFile.cxx
+++ b/Source/cmSourceFile.cxx
@@ -16,9 +16,12 @@
 #include "cmake.h"
 
 cmSourceFile::cmSourceFile(cmMakefile* mf, const std::string& name,
-                           cmSourceFileLocationKind kind)
-  : Location(mf, name, kind)
+                           bool generated, cmSourceFileLocationKind kind)
+  : Location(mf, name, (!generated) ? kind : cmSourceFileLocationKind::Known)
 {
+  if (generated) {
+    this->MarkAsGenerated();
+  }
 }
 
 std::string const& cmSourceFile::GetExtension() const
@@ -26,6 +29,8 @@ std::string const& cmSourceFile::GetExtension() const
   return this->Extension;
 }
 
+const std::string propTRUE = "1";
+const std::string propFALSE = "0";
 const std::string cmSourceFile::propLANGUAGE = "LANGUAGE";
 const std::string cmSourceFile::propLOCATION = "LOCATION";
 const std::string cmSourceFile::propGENERATED = "GENERATED";
@@ -55,16 +60,14 @@ std::string const& cmSourceFile::GetOrDetermineLanguage()
   }
 
   // Perform computation needed to get the language if necessary.
-  if (this->FullPath.empty() && this->Language.empty()) {
-    // If a known extension is given or a known full path is given
-    // then trust that the current extension is sufficient to
-    // determine the language.  This will fail only if the user
-    // specifies a full path to the source but leaves off the
-    // extension, which is kind of weird.
-    if (this->Location.ExtensionIsAmbiguous() &&
+  if (this->Language.empty()) {
+    // If a known extension is given or a known full path is given then trust
+    // that the current extension is sufficient to determine the language. This
+    // will fail only if the user specifies a full path to the source but
+    // leaves off the extension, which is kind of weird.
+    if (this->FullPath.empty() && this->Location.ExtensionIsAmbiguous() &&
         this->Location.DirectoryIsAmbiguous()) {
-      // Finalize the file location to get the extension and set the
-      // language.
+      // Finalize the file location to get the extension and set the language.
       this->ResolveFullPath();
     } else {
       // Use the known extension to get the language if possible.
@@ -114,11 +117,14 @@ bool cmSourceFile::FindFullPath(std::string* error,
                                 std::string* cmp0115Warning)
 {
   // If the file is generated compute the location without checking on disk.
-  if (this->GetIsGenerated()) {
+  // Note: We also check for a locally set GENERATED property, because
+  //       it might have been set before policy CMP0118 was set to NEW.
+  if (this->GetIsGenerated(CheckScope::GlobalAndLocal)) {
     // The file is either already a full path or is relative to the
     // build directory for the target.
     this->Location.DirectoryUseBinary();
     this->FullPath = this->Location.GetFullPath();
+    this->FindFullPathFailed = false;
     return true;
   }
 
@@ -275,11 +281,6 @@ void cmSourceFile::SetProperty(const std::string& prop, const char* value)
   } else {
     this->Properties.SetProperty(prop, value);
   }
-
-  // Update IsGenerated flag
-  if (prop == propGENERATED) {
-    this->IsGenerated = cmIsOn(value);
-  }
 }
 
 void cmSourceFile::AppendProperty(const std::string& prop,
@@ -303,11 +304,6 @@ void cmSourceFile::AppendProperty(const std::string& prop,
   } else {
     this->Properties.AppendProperty(prop, value, asString);
   }
-
-  // Update IsGenerated flag
-  if (prop == propGENERATED) {
-    this->IsGenerated = this->GetPropertyAsBool(propGENERATED);
-  }
 }
 
 cmProp cmSourceFile::GetPropertyForUser(const std::string& prop)
@@ -338,6 +334,21 @@ cmProp cmSourceFile::GetPropertyForUser(const std::string& prop)
     return &this->GetOrDetermineLanguage();
   }
 
+  // Special handling for GENERATED property.
+  if (prop == propGENERATED) {
+    // We need to check policy CMP0118 in order to determine if we need to
+    // possibly consider the value of a locally set GENERATED property, too.
+    auto policyStatus =
+      this->Location.GetMakefile()->GetPolicyStatus(cmPolicies::CMP0118);
+    if (this->GetIsGenerated(
+          (policyStatus == cmPolicies::WARN || policyStatus == cmPolicies::OLD)
+            ? CheckScope::GlobalAndLocal
+            : CheckScope::Global)) {
+      return &propTRUE;
+    }
+    return &propFALSE;
+  }
+
   // Perform the normal property lookup.
   return this->GetProperty(prop);
 }
@@ -413,11 +424,29 @@ bool cmSourceFile::GetPropertyAsBool(const std::string& prop) const
   return cmIsOn(this->GetProperty(prop));
 }
 
+void cmSourceFile::MarkAsGenerated()
+{
+  this->IsGenerated = true;
+  auto& mf = *this->Location.GetMakefile();
+  mf.GetGlobalGenerator()->MarkAsGeneratedFile(this->ResolveFullPath());
+}
+
+bool cmSourceFile::GetIsGenerated(CheckScope checkScope) const
+{
+  if (this->IsGenerated) {
+    // Globally marked as generated!
+    return true;
+  }
+  if (checkScope == CheckScope::GlobalAndLocal) {
+    // Check locally stored properties.
+    return this->GetPropertyAsBool(propGENERATED);
+  }
+  return false;
+}
+
 void cmSourceFile::SetProperties(cmPropertyMap properties)
 {
   this->Properties = std::move(properties);
-
-  this->IsGenerated = this->GetPropertyAsBool(propGENERATED);
 }
 
 cmCustomCommand* cmSourceFile::GetCustomCommand() const
diff --git a/Source/cmSourceFile.h b/Source/cmSourceFile.h
index 3ad2664..94b5cc8 100644
--- a/Source/cmSourceFile.h
+++ b/Source/cmSourceFile.h
@@ -20,18 +20,18 @@ class cmMakefile;
 /** \class cmSourceFile
  * \brief Represent a class loaded from a makefile.
  *
- * cmSourceFile is represents a class loaded from
- * a makefile.
+ * cmSourceFile represents a class loaded from a makefile.
  */
 class cmSourceFile
 {
 public:
   /**
-   * Construct with the makefile storing the source and the initial
-   * name referencing it.
+   * Construct with the makefile storing the source and the initial name
+   * referencing it. If it shall be marked as generated, this source file's
+   * kind is assumed to be known, regardless of the given value.
    */
   cmSourceFile(
-    cmMakefile* mf, const std::string& name,
+    cmMakefile* mf, const std::string& name, bool generated,
     cmSourceFileLocationKind kind = cmSourceFileLocationKind::Ambiguous);
 
   /**
@@ -54,9 +54,29 @@ public:
       command like get_property or get_source_file_property.  */
   cmProp GetPropertyForUser(const std::string& prop);
 
-  //! Checks is the GENERATED property is set and true
-  /// @return Equivalent to GetPropertyAsBool("GENERATED")
-  bool GetIsGenerated() const { return this->IsGenerated; }
+  /// Marks this file as generated
+  /**
+   * This stores this file's path in the global table for all generated source
+   * files.
+   */
+  void MarkAsGenerated();
+  enum class CheckScope
+  {
+    Global,
+    GlobalAndLocal
+  };
+  /// Determines if this source file is marked as generated.
+  /**
+   * This will check if this file's path is stored in the global table of all
+   * generated source files. If that is not the case and checkScope is set to
+   * GlobalAndLocal the value of the possibly existing local GENERATED property
+   * is returned instead.
+   * @param checkScope Determines if alternatively for backwards-compatibility
+   * a local GENERATED property should be considered, too.
+   * @return true if this source file is marked as generated, otherwise false.
+   */
+  bool GetIsGenerated(
+    CheckScope checkScope = CheckScope::GlobalAndLocal) const;
 
   const std::vector<BT<std::string>>& GetCompileOptions() const
   {