Merge topic 'ninja-gfortran-fpreprocessed'

90a34ff7 Ninja: Fix references to source files in gfortran diagnostics

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1146

Modules/Compiler/GNU-Fortran.cmake

@@ -7,6 +7,8 @@ set(CMAKE_Fortran_PREPROCESS_SOURCE
 set(CMAKE_Fortran_FORMAT_FIXED_FLAG "-ffixed-form")
 set(CMAKE_Fortran_FORMAT_FREE_FLAG "-ffree-form")
 
+set(CMAKE_Fortran_POSTPROCESS_FLAG "-fpreprocessed")
+
 # No -DNDEBUG for Fortran.
 string(APPEND CMAKE_Fortran_FLAGS_MINSIZEREL_INIT " -Os")
 string(APPEND CMAKE_Fortran_FLAGS_RELEASE_INIT " -O3")

Source/cmNinjaTargetGenerator.cxx

@@ -891,9 +891,15 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatement(
     // The actual compilation will now use the preprocessed source.
     explicitDeps.push_back(ppFileName);
 
-    // Preprocessing and compilation use the same flags.
+    // Preprocessing and compilation generally use the same flags.
     ppVars["FLAGS"] = vars["FLAGS"];
 
+    // In case compilation requires flags that are incompatible with
+    // preprocessing, include them here.
+    std::string const postFlag =
+      this->Makefile->GetSafeDefinition("CMAKE_Fortran_POSTPROCESS_FLAG");
+    this->LocalGenerator->AppendFlags(vars["FLAGS"], postFlag);
+
     // Move preprocessor definitions to the preprocessor build statement.
     std::swap(ppVars["DEFINES"], vars["DEFINES"]);