Ninja: Fix Fortran support with response files

The Ninja generator splits preprocessing and compilation steps for
Fortran.  Fix this logic to work when using response files for
compilation so that it works for the preprocessing step too.

This fixes behavior under `CMAKE_NINJA_FORCE_RESPONSE_FILE`.

Issue: #17877

Source/cmNinjaTargetGenerator.cxx

@@ -445,24 +445,16 @@ void cmNinjaTargetGenerator::WriteCompileRule(const std::string& lang)
   cmMakefile* mf = this->GetMakefile();
 
   std::string flags = "$FLAGS";
-  std::string rspfile;
-  std::string rspcontent;
 
+  std::string responseFlag;
   bool const lang_supports_response = !(lang == "RC" || lang == "CUDA");
   if (lang_supports_response && this->ForceResponseFile()) {
     std::string const responseFlagVar =
       "CMAKE_" + lang + "_RESPONSE_FILE_FLAG";
-    std::string responseFlag =
-      this->Makefile->GetSafeDefinition(responseFlagVar);
+    responseFlag = this->Makefile->GetSafeDefinition(responseFlagVar);
     if (responseFlag.empty()) {
       responseFlag = "@";
     }
-    rspfile = "$RSP_FILE";
-    responseFlag += rspfile;
-    rspcontent = " $DEFINES $INCLUDES $FLAGS";
-    flags = std::move(responseFlag);
-    vars.Defines = "";
-    vars.Includes = "";
   }
 
   std::unique_ptr<cmRulePlaceholderExpander> rulePlaceholderExpander(
@@ -514,6 +506,18 @@ void cmNinjaTargetGenerator::WriteCompileRule(const std::string& lang)
     // compilation rule still needs them for the INCLUDE directive.
     ppVars.Includes = vars.Includes;
 
+    // If using a response file, move defines, includes, and flags into it.
+    std::string ppRspFile;
+    std::string ppRspContent;
+    if (!responseFlag.empty()) {
+      ppRspFile = "$RSP_FILE";
+      ppRspContent = std::string(" ") + ppVars.Defines + " " +
+        ppVars.Includes + " " + ppFlags;
+      ppFlags = responseFlag + ppRspFile;
+      ppVars.Defines = "";
+      ppVars.Includes = "";
+    }
+
     ppVars.Flags = ppFlags.c_str();
 
     // Rule for preprocessing source file.
@@ -544,13 +548,11 @@ void cmNinjaTargetGenerator::WriteCompileRule(const std::string& lang)
     ppComment << "Rule for preprocessing " << lang << " files.";
     std::ostringstream ppDesc;
     ppDesc << "Building " << lang << " preprocessed $out";
-    this->GetGlobalGenerator()->AddRule(this->LanguagePreprocessRule(lang),
-                                        ppCmdLine, ppDesc.str(),
-                                        ppComment.str(), ppDepfile, ppDeptype,
-                                        /*rspfile*/ "",
-                                        /*rspcontent*/ "",
-                                        /*restat*/ "",
-                                        /*generator*/ false);
+    this->GetGlobalGenerator()->AddRule(
+      this->LanguagePreprocessRule(lang), ppCmdLine, ppDesc.str(),
+      ppComment.str(), ppDepfile, ppDeptype, ppRspFile, ppRspContent,
+      /*restat*/ "",
+      /*generator*/ false);
   }
 
   if (needDyndep) {
@@ -587,6 +589,18 @@ void cmNinjaTargetGenerator::WriteCompileRule(const std::string& lang)
       /*generator*/ false);
   }
 
+  // If using a response file, move defines, includes, and flags into it.
+  std::string rspfile;
+  std::string rspcontent;
+  if (!responseFlag.empty()) {
+    rspfile = "$RSP_FILE";
+    rspcontent =
+      std::string(" ") + vars.Defines + " " + vars.Includes + " " + flags;
+    flags = responseFlag + rspfile;
+    vars.Defines = "";
+    vars.Includes = "";
+  }
+
   // Tell ninja dependency format so all deps can be loaded into a database
   std::string deptype;
   std::string depfile;
@@ -1019,9 +1033,12 @@ void cmNinjaTargetGenerator::WriteObjectBuildStatement(
     this->addPoolNinjaVariable("JOB_POOL_COMPILE", this->GetGeneratorTarget(),
                                ppVars);
 
+    std::string const ppRspFile = ppFileName + ".rsp";
+
     this->GetGlobalGenerator()->WriteBuild(
       this->GetBuildFileStream(), ppComment, ppRule, ppOutputs, ppImplicitOuts,
-      ppExplicitDeps, ppImplicitDeps, ppOrderOnlyDeps, ppVars);
+      ppExplicitDeps, ppImplicitDeps, ppOrderOnlyDeps, ppVars, ppRspFile,
+      commandLineLengthLimit);
   }
   if (needDyndep) {
     std::string const dyndep = this->GetDyndepFilePath(language);

Tests/RunCMake/CMakeLists.txt

@@ -121,6 +121,9 @@ if(CMAKE_GENERATOR STREQUAL "Ninja")
     -DCMAKE_C_OUTPUT_EXTENSION=${CMAKE_C_OUTPUT_EXTENSION}
     -DCMAKE_SHARED_LIBRARY_PREFIX=${CMAKE_SHARED_LIBRARY_PREFIX}
     -DCMAKE_SHARED_LIBRARY_SUFFIX=${CMAKE_SHARED_LIBRARY_SUFFIX})
+  if(CMAKE_Fortran_COMPILER)
+    list(APPEND Ninja_ARGS -DTEST_Fortran=1)
+  endif()
   add_RunCMake_test(Ninja)
 endif()
 add_RunCMake_test(CTest)

Tests/RunCMake/Ninja/RspFileC.cmake

@@ -0,0 +1,2 @@
+set(ENV{CMAKE_NINJA_FORCE_RESPONSE_FILE} 1)
+enable_language(C)

Tests/RunCMake/Ninja/RspFileCXX.cmake

@@ -0,0 +1,2 @@
+set(ENV{CMAKE_NINJA_FORCE_RESPONSE_FILE} 1)
+enable_language(CXX)

Tests/RunCMake/Ninja/RspFileFortran.cmake

@@ -0,0 +1,2 @@
+set(ENV{CMAKE_NINJA_FORCE_RESPONSE_FILE} 1)
+enable_language(Fortran)

Tests/RunCMake/Ninja/RunCMakeTest.cmake

@@ -40,6 +40,12 @@ run_CMP0058(NEW-by)
 
 run_cmake(CustomCommandDepfile)
 
+run_cmake(RspFileC)
+run_cmake(RspFileCXX)
+if(TEST_Fortran)
+  run_cmake(RspFileFortran)
+endif()
+
 function(run_CommandConcat)
   set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/CommandConcat-build)
   set(RunCMake_TEST_NO_CLEAN 1)