Makefiles: support shortened object filenames

Help/release/dev/short-object-names.rst

@@ -8,3 +8,6 @@ short-object-names
   is supported for the following generators:
 
   - :ref:`Ninja Generators`
+  - :ref:`Makefile Generators`
+
+  Note that the strategy implementation may differ between generators.

Source/cmGlobalBorlandMakefileGenerator.cxx

@@ -80,6 +80,11 @@ cmGlobalBorlandMakefileGenerator::GenerateBuildCommand(
     cmake::NO_BUILD_PARALLEL_LEVEL, verbose, buildOptions, makeOptions);
 }
 
+std::string cmGlobalBorlandMakefileGenerator::GetShortBinaryOutputDir() const
+{
+  return "_o";
+}
+
 void cmGlobalBorlandMakefileGenerator::PrintBuildCommandAdvice(
   std::ostream& os, int jobs) const
 {

Source/cmGlobalBorlandMakefileGenerator.h

@@ -56,6 +56,8 @@ public:
 
   bool IsGNUMakeJobServerAware() const override { return false; }
 
+  std::string GetShortBinaryOutputDir() const override;
+
 protected:
   std::vector<GeneratedMakeCommand> GenerateBuildCommand(
     std::string const& makeProgram, std::string const& projectName,

Source/cmGlobalUnixMakefileGenerator3.cxx

@@ -77,6 +77,11 @@ cmDocumentationEntry cmGlobalUnixMakefileGenerator3::GetDocumentation()
            "Generates standard UNIX makefiles." };
 }
 
+bool cmGlobalUnixMakefileGenerator3::SupportsShortObjectNames() const
+{
+  return true;
+}
+
 void cmGlobalUnixMakefileGenerator3::ComputeTargetObjectDirectory(
   cmGeneratorTarget* gt) const
 {

Source/cmGlobalUnixMakefileGenerator3.h

@@ -195,6 +195,7 @@ public:
 
   bool IsIPOSupported() const override { return true; }
 
+  bool SupportsShortObjectNames() const override;
   void ComputeTargetObjectDirectory(cmGeneratorTarget* gt) const override;
 
   std::string IncludeDirective;

Source/cmGlobalWatcomWMakeGenerator.cxx

@@ -75,6 +75,11 @@ cmGlobalWatcomWMakeGenerator::GenerateBuildCommand(
     cmake::NO_BUILD_PARALLEL_LEVEL, verbose, buildOptions, makeOptions);
 }
 
+std::string cmGlobalWatcomWMakeGenerator::GetShortBinaryOutputDir() const
+{
+  return "_o";
+}
+
 void cmGlobalWatcomWMakeGenerator::PrintBuildCommandAdvice(std::ostream& os,
                                                            int jobs) const
 {

Source/cmGlobalWatcomWMakeGenerator.h

@@ -55,6 +55,8 @@ public:
 
   bool IsGNUMakeJobServerAware() const override { return false; }
 
+  std::string GetShortBinaryOutputDir() const override;
+
 protected:
   std::vector<GeneratedMakeCommand> GenerateBuildCommand(
     std::string const& makeProgram, std::string const& projectName,

Source/cmLocalUnixMakefileGenerator3.cxx

@@ -201,6 +201,15 @@ void cmLocalUnixMakefileGenerator3::Generate()
   this->WriteDirectoryInformationFile();
 }
 
+std::string cmLocalUnixMakefileGenerator3::GetObjectOutputRoot() const
+{
+  if (this->UseShortObjectNames()) {
+    return cmStrCat(this->GetCurrentBinaryDirectory(), '/',
+                    this->GetGlobalGenerator()->GetShortBinaryOutputDir());
+  }
+  return cmStrCat(this->GetCurrentBinaryDirectory(), "/CMakeFiles");
+}
+
 void cmLocalUnixMakefileGenerator3::ComputeHomeRelativeOutputPath()
 {
   // Compute the path to use when referencing the current output

Source/cmLocalUnixMakefileGenerator3.h

@@ -43,6 +43,8 @@ public:
    */
   void Generate() override;
 
+  std::string GetObjectOutputRoot() const override;
+
   // this returns the relative path between the HomeOutputDirectory and this
   // local generators StartOutputDirectory
   std::string const& GetHomeRelativeOutputPath();

Tests/RunCMake/Make/RunCMakeTest.cmake

@@ -39,6 +39,29 @@ function(run_VerboseBuild)
 endfunction()
 run_VerboseBuild()
 
+function(run_VerboseBuildShort)
+  run_cmake(VerboseBuildShort)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/VerboseBuildShort-build)
+  if(RunCMake_GENERATOR STREQUAL "Watcom WMake")
+    # wmake does not actually show the verbose output.
+    set(RunCMake-stdout-file VerboseBuildShort-build-watcom-stdout.txt)
+  endif()
+  run_cmake_command(VerboseBuildShort-build ${CMAKE_COMMAND} --build . -v --clean-first)
+  unset(RunCMake-stdout-file)
+  set(_backup_lang "$ENV{LANG}")
+  set(_backup_lc_Messages "$ENV{LC_MESSAGES}")
+  if(MAKE_IS_GNU)
+    set(RunCMake-stdout-file VerboseBuildShort-nowork-gnu-stdout.txt)
+    set(ENV{LANG} "C")
+    set(ENV{LC_MESSAGES} "C")
+  endif()
+  run_cmake_command(VerboseBuildShort-nowork ${CMAKE_COMMAND} --build . --verbose)
+  set(ENV{LANG} "${_backup_lang}")
+  set(ENV{LC_MESSAGES} "${_backup_lc_messages}")
+endfunction()
+run_VerboseBuildShort()
+
 run_cmake(IncludeRegexSubdir)
 
 function(run_MakefileConflict)

Tests/RunCMake/Make/VerboseBuild.cmake

@@ -1,3 +1,5 @@
+set(CMAKE_INTERMEDIATE_DIR_STRATEGY FULL CACHE STRING "" FORCE)
+
 enable_language(C)
 
 # Make sure compile command is not hidden in a temp file.

Tests/RunCMake/Make/VerboseBuildShort-build-stdout.txt

@@ -0,0 +1 @@
+DEFINE_FOR_VERBOSE_DETECTION.*.o[\\/]75d5d702[\\/]4efa03e1

Tests/RunCMake/Make/VerboseBuildShort-build-watcom-stdout.txt

@@ -0,0 +1 @@
+Building C object _o/75d5d702/4efa03e1.obj

Tests/RunCMake/Make/VerboseBuildShort-nowork-gnu-stdout.txt

@@ -0,0 +1 @@
+.*Nothing to be done for.*hello.*

Tests/RunCMake/Make/VerboseBuildShort.cmake

@@ -0,0 +1,10 @@
+set(CMAKE_INTERMEDIATE_DIR_STRATEGY SHORT CACHE STRING "" FORCE)
+
+enable_language(C)
+
+# Make sure compile command is not hidden in a temp file.
+string(REPLACE "${CMAKE_START_TEMP_FILE}" "" CMAKE_C_COMPILE_OBJECT "${CMAKE_C_COMPILE_OBJECT}")
+string(REPLACE "${CMAKE_END_TEMP_FILE}" "" CMAKE_C_COMPILE_OBJECT "${CMAKE_C_COMPILE_OBJECT}")
+
+add_executable(hello hello.c)
+target_compile_definitions(hello PRIVATE "DEFINE_FOR_VERBOSE_DETECTION")

Tests/RunCMake/ObjectLibrary/RunCMakeTest.cmake

@@ -91,6 +91,6 @@ function(run_Dependencies suffix)
 endfunction()
 
 run_Dependencies("")
-if (CMAKE_GENERATOR MATCHES "Ninja")
+if (CMAKE_GENERATOR MATCHES "(Ninja|Makefiles)")
   run_Dependencies(Short)
 endif ()

Tests/RunCMake/PrecompileHeaders/RunCMakeTest.cmake

@@ -18,7 +18,7 @@ endfunction()
 run_cmake(DisabledPch)
 run_cmake(PchDebugGenex)
 run_test(PchInterface)
-if (CMAKE_GENERATOR MATCHES "Ninja")
+if (CMAKE_GENERATOR MATCHES "(Ninja|Makefiles)")
   run_test(PchInterfaceShort)
 endif ()
 run_test(PchInterfaceUnity)

Tests/RunCMake/UnityBuild/RunCMakeTest.cmake

@@ -72,6 +72,6 @@ endfunction()
 run_test(unitybuild_runtest)
 run_test(unitybuild_object_library)
 
-if (CMAKE_GENERATOR MATCHES "Ninja")
+if (CMAKE_GENERATOR MATCHES "(Ninja|Makefiles)")
   run_build(unitybuild_cxx_short)
 endif ()