Merge topic 'makefile-simplify-fortran'

7ab9a625 Makefiles: Drop 'requires' step and its supporting infrastructure
5f2e2c38 Makefiles: Avoid nested make calls for Fortran module dependencies

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1523

9 files changed, 22 insertions, 140 deletions

diff --git a/Modules/CMakeFortranInformation.cmake b/Modules/CMakeFortranInformation.cmake
index b315d33..d422578 100644
--- a/Modules/CMakeFortranInformation.cmake
+++ b/Modules/CMakeFortranInformation.cmake
@@ -67,11 +67,6 @@ if(CMAKE_USER_MAKE_RULES_OVERRIDE_Fortran)
   set(CMAKE_USER_MAKE_RULES_OVERRIDE_Fortran "${_override}")
 endif()
 
-
-# Fortran needs cmake to do a requires step during its build process to
-# catch any modules
-set(CMAKE_NEEDS_REQUIRES_STEP_Fortran_FLAG 1)
-
 if(NOT CMAKE_Fortran_COMPILE_OPTIONS_PIC)
   set(CMAKE_Fortran_COMPILE_OPTIONS_PIC ${CMAKE_C_COMPILE_OPTIONS_PIC})
 endif()
diff --git a/Source/cmDependsFortran.cxx b/Source/cmDependsFortran.cxx
index fdbc086..23f622b 100644
--- a/Source/cmDependsFortran.cxx
+++ b/Source/cmDependsFortran.cxx
@@ -331,24 +331,6 @@ bool cmDependsFortran::WriteDependenciesReal(const char* obj,
       continue;
     }
 
-    // If the module is provided in this target special handling is
-    // needed.
-    if (this->Internal->TargetProvides.find(i) !=
-        this->Internal->TargetProvides.end()) {
-      // The module is provided by a different source in the same
-      // target.  Add the proxy dependency to make sure the other
-      // source builds first.
-      std::string proxy = stamp_dir;
-      proxy += "/";
-      proxy += i;
-      proxy += ".mod.proxy";
-      proxy = cmSystemTools::ConvertToOutputPath(
-        this->MaybeConvertToRelativePath(binDir, proxy).c_str());
-
-      // since we require some things add them to our list of requirements
-      makeDepends << obj_m << ".requires: " << proxy << std::endl;
-    }
-
     // The object file should depend on timestamped files for the
     // modules it uses.
     TargetRequiresMap::const_iterator required =
@@ -373,22 +355,10 @@ bool cmDependsFortran::WriteDependenciesReal(const char* obj,
     }
   }
 
-  // Write provided modules to the output stream.
-  for (std::string const& i : info.Provides) {
-    std::string proxy = stamp_dir;
-    proxy += "/";
-    proxy += i;
-    proxy += ".mod.proxy";
-    proxy = cmSystemTools::ConvertToOutputPath(
-      this->MaybeConvertToRelativePath(binDir, proxy).c_str());
-    makeDepends << proxy << ": " << obj_m << ".provides" << std::endl;
-  }
-
   // If any modules are provided then they must be converted to stamp files.
   if (!info.Provides.empty()) {
     // Create a target to copy the module after the object file
     // changes.
-    makeDepends << obj_m << ".provides.build:\n";
     for (std::string const& i : info.Provides) {
       // Include this module in the set provided by this target.
       this->Internal->TargetProvides.insert(i);
@@ -407,11 +377,25 @@ bool cmDependsFortran::WriteDependenciesReal(const char* obj,
       stampFile += "/";
       stampFile += m;
       stampFile += ".mod.stamp";
-      stampFile = this->LocalGenerator->ConvertToOutputFormat(
-        this->MaybeConvertToRelativePath(binDir, stampFile),
-        cmOutputConverter::SHELL);
+      stampFile = this->MaybeConvertToRelativePath(binDir, stampFile);
+      std::string const stampFileForShell =
+        this->LocalGenerator->ConvertToOutputFormat(stampFile,
+                                                    cmOutputConverter::SHELL);
+      std::string const stampFileForMake =
+        cmSystemTools::ConvertToOutputPath(stampFile.c_str());
+
+      makeDepends << obj_m << ".provides.build"
+                  << ": " << stampFileForMake << "\n";
+      // Note that when cmake_copy_f90_mod finds that a module file
+      // and the corresponding stamp file have no differences, the stamp
+      // file is not updated. In such case the stamp file will be always
+      // older than its prerequisite and trigger cmake_copy_f90_mod
+      // on each new build. This is expected behavior for incremental
+      // builds and can not be changed without preforming recursive make
+      // calls that would considerably slow down the building process.
+      makeDepends << stampFileForMake << ": " << obj_m << "\n";
       makeDepends << "\t$(CMAKE_COMMAND) -E cmake_copy_f90_mod " << modFile
-                  << " " << stampFile;
+                  << " " << stampFileForShell;
       cmMakefile* mf = this->LocalGenerator->GetMakefile();
       const char* cid = mf->GetDefinition("CMAKE_Fortran_COMPILER_ID");
       if (cid && *cid) {
@@ -419,8 +403,8 @@ bool cmDependsFortran::WriteDependenciesReal(const char* obj,
       }
       makeDepends << "\n";
     }
-    // After copying the modules update the timestamp file so that
-    // copying will not be done again until the source rebuilds.
+    makeDepends << obj_m << ".provides.build:\n";
+    // After copying the modules update the timestamp file.
     makeDepends << "\t$(CMAKE_COMMAND) -E touch " << obj_m
                 << ".provides.build\n";
 
diff --git a/Source/cmGlobalUnixMakefileGenerator3.cxx b/Source/cmGlobalUnixMakefileGenerator3.cxx
index be40126..236bb3d 100644
--- a/Source/cmGlobalUnixMakefileGenerator3.cxx
+++ b/Source/cmGlobalUnixMakefileGenerator3.cxx
@@ -21,7 +21,6 @@
 #include "cmStateDirectory.h"
 #include "cmStateTypes.h"
 #include "cmSystemTools.h"
-#include "cmTarget.h"
 #include "cmTargetDepend.h"
 #include "cmake.h"
 
@@ -630,8 +629,6 @@ void cmGlobalUnixMakefileGenerator3::WriteConvenienceRules2(
       makefileName = localName;
       makefileName += "/build.make";
 
-      bool needRequiresStep = this->NeedRequiresStep(gtarget);
-
       lg->WriteDivider(ruleFileStream);
       ruleFileStream << "# Target rules for target " << localName << "\n\n";
 
@@ -641,13 +638,6 @@ void cmGlobalUnixMakefileGenerator3::WriteConvenienceRules2(
       commands.push_back(
         lg->GetRecursiveMakeCall(makefileName.c_str(), makeTargetName));
 
-      // add requires if we need it for this generator
-      if (needRequiresStep) {
-        makeTargetName = localName;
-        makeTargetName += "/requires";
-        commands.push_back(
-          lg->GetRecursiveMakeCall(makefileName.c_str(), makeTargetName));
-      }
       makeTargetName = localName;
       makeTargetName += "/build";
       commands.push_back(
@@ -952,21 +942,3 @@ void cmGlobalUnixMakefileGenerator3::WriteHelpRule(
                     commands, true);
   ruleFileStream << "\n\n";
 }
-
-bool cmGlobalUnixMakefileGenerator3::NeedRequiresStep(
-  const cmGeneratorTarget* target)
-{
-  std::set<std::string> languages;
-  target->GetLanguages(
-    languages,
-    target->Target->GetMakefile()->GetSafeDefinition("CMAKE_BUILD_TYPE"));
-  for (std::string const& l : languages) {
-    std::string var = "CMAKE_NEEDS_REQUIRES_STEP_";
-    var += l;
-    var += "_FLAG";
-    if (target->Target->GetMakefile()->GetDefinition(var)) {
-      return true;
-    }
-  }
-  return false;
-}
diff --git a/Source/cmGlobalUnixMakefileGenerator3.h b/Source/cmGlobalUnixMakefileGenerator3.h
index d601f88..f9ce88c 100644
--- a/Source/cmGlobalUnixMakefileGenerator3.h
+++ b/Source/cmGlobalUnixMakefileGenerator3.h
@@ -174,9 +174,6 @@ protected:
   void AppendGlobalTargetDepends(std::vector<std::string>& depends,
                                  cmGeneratorTarget* target);
 
-  // does this generator need a requires step for any of its targets
-  bool NeedRequiresStep(cmGeneratorTarget const*);
-
   // Target name hooks for superclass.
   const char* GetAllTargetName() const override { return "all"; }
   const char* GetInstallTargetName() const override { return "install"; }
diff --git a/Source/cmLocalUnixMakefileGenerator3.cxx b/Source/cmLocalUnixMakefileGenerator3.cxx
index e26182a..a389ad0 100644
--- a/Source/cmLocalUnixMakefileGenerator3.cxx
+++ b/Source/cmLocalUnixMakefileGenerator3.cxx
@@ -1444,6 +1444,8 @@ bool cmLocalUnixMakefileGenerator3::ScanDependencies(
     }
 #ifdef CMAKE_BUILD_WITH_CMAKE
     else if (lang == "Fortran") {
+      ruleFileStream << "# Note that incremental build could trigger "
+                     << "a call to cmake_copy_f90_mod on each re-build\n";
       scanner = new cmDependsFortran(this);
     } else if (lang == "Java") {
       scanner = new cmDependsJava();
diff --git a/Source/cmMakefileExecutableTargetGenerator.cxx b/Source/cmMakefileExecutableTargetGenerator.cxx
index 801f72a..90d8c7f 100644
--- a/Source/cmMakefileExecutableTargetGenerator.cxx
+++ b/Source/cmMakefileExecutableTargetGenerator.cxx
@@ -69,9 +69,6 @@ void cmMakefileExecutableTargetGenerator::WriteRuleFiles()
     this->WriteExecutableRule(true);
   }
 
-  // Write the requires target.
-  this->WriteTargetRequiresRules();
-
   // Write clean target
   this->WriteTargetCleanRules();
 
diff --git a/Source/cmMakefileLibraryTargetGenerator.cxx b/Source/cmMakefileLibraryTargetGenerator.cxx
index 80c62d1..ab15daf 100644
--- a/Source/cmMakefileLibraryTargetGenerator.cxx
+++ b/Source/cmMakefileLibraryTargetGenerator.cxx
@@ -89,9 +89,6 @@ void cmMakefileLibraryTargetGenerator::WriteRuleFiles()
       break;
   }
 
-  // Write the requires target.
-  this->WriteTargetRequiresRules();
-
   // Write clean target
   this->WriteTargetCleanRules();
 
diff --git a/Source/cmMakefileTargetGenerator.cxx b/Source/cmMakefileTargetGenerator.cxx
index 82506d2..850b8b2 100644
--- a/Source/cmMakefileTargetGenerator.cxx
+++ b/Source/cmMakefileTargetGenerator.cxx
@@ -824,65 +824,6 @@ void cmMakefileTargetGenerator::WriteObjectBuildFile(
                                           commands, false);
     }
   }
-
-  // If the language needs provides-requires mode, create the
-  // corresponding targets.
-  std::string objectRequires = relativeObj;
-  objectRequires += ".requires";
-  std::vector<std::string> p_depends;
-  // always provide an empty requires target
-  this->LocalGenerator->WriteMakeRule(*this->BuildFileStream, nullptr,
-                                      objectRequires, p_depends, no_commands,
-                                      true);
-
-  // write a build rule to recursively build what this obj provides
-  std::string objectProvides = relativeObj;
-  objectProvides += ".provides";
-  std::string temp = relativeObj;
-  temp += ".provides.build";
-  std::vector<std::string> r_commands;
-  std::string tgtMakefileName =
-    this->LocalGenerator->GetRelativeTargetDirectory(this->GeneratorTarget);
-  tgtMakefileName += "/build.make";
-  r_commands.push_back(
-    this->LocalGenerator->GetRecursiveMakeCall(tgtMakefileName.c_str(), temp));
-
-  p_depends.clear();
-  p_depends.push_back(objectRequires);
-  this->LocalGenerator->WriteMakeRule(*this->BuildFileStream, nullptr,
-                                      objectProvides, p_depends, r_commands,
-                                      true);
-
-  // write the provides.build rule dependency on the obj file
-  p_depends.clear();
-  p_depends.push_back(relativeObj);
-  this->LocalGenerator->WriteMakeRule(*this->BuildFileStream, nullptr, temp,
-                                      p_depends, no_commands, false);
-}
-
-void cmMakefileTargetGenerator::WriteTargetRequiresRules()
-{
-  std::vector<std::string> depends;
-  std::vector<std::string> no_commands;
-
-  // Construct the name of the dependency generation target.
-  std::string depTarget =
-    this->LocalGenerator->GetRelativeTargetDirectory(this->GeneratorTarget);
-  depTarget += "/requires";
-
-  // This target drives dependency generation for all object files.
-  std::string relPath = this->LocalGenerator->GetHomeRelativeOutputPath();
-  std::string objTarget;
-  for (std::string const& obj : this->Objects) {
-    objTarget = relPath;
-    objTarget += obj;
-    objTarget += ".requires";
-    depends.push_back(objTarget);
-  }
-
-  // Write the rule.
-  this->LocalGenerator->WriteMakeRule(*this->BuildFileStream, nullptr,
-                                      depTarget, depends, no_commands, true);
 }
 
 void cmMakefileTargetGenerator::WriteTargetCleanRules()
diff --git a/Source/cmMakefileTargetGenerator.h b/Source/cmMakefileTargetGenerator.h
index 5ab7e36..7af3cf3 100644
--- a/Source/cmMakefileTargetGenerator.h
+++ b/Source/cmMakefileTargetGenerator.h
@@ -63,9 +63,6 @@ protected:
   void WriteCommonCodeRules();
   void WriteTargetLanguageFlags();
 
-  // write the provide require rules for this target
-  void WriteTargetRequiresRules();
-
   // write the clean rules for this target
   void WriteTargetCleanRules();