ENH: Added OBJECT_OUTPUTS source file property. Updated PrecompiledHeader test to use it (making the test simpler).

Source/cmMakefileTargetGenerator.cxx

@@ -517,6 +517,25 @@ cmMakefileTargetGenerator
                                       relativeObj.c_str(),
                                       depends, commands, false);
 
+  // Check for extra outputs created by the compilation.
+  if(const char* extra_outputs_str =
+     source.GetProperty("OBJECT_OUTPUTS"))
+    {
+    std::vector<std::string> extra_outputs;
+    cmSystemTools::ExpandListArgument(extra_outputs_str, extra_outputs);
+    for(std::vector<std::string>::const_iterator eoi = extra_outputs.begin();
+        eoi != extra_outputs.end(); ++eoi)
+      {
+      // Register this as an extra output for the object file rule.
+      // This will cause the object file to be rebuilt if the extra
+      // output is missing.
+      this->GenerateExtraOutput(eoi->c_str(), relativeObj.c_str(), false);
+
+      // Register this as an extra file to clean.
+      this->CleanFiles.push_back(eoi->c_str());
+      }
+    }
+
   bool lang_is_c_or_cxx = ((strcmp(lang, "C") == 0) ||
                            (strcmp(lang, "CXX") == 0));
   bool do_preprocess_rules = lang_is_c_or_cxx &&

Source/cmSourceFile.cxx

@@ -401,6 +401,14 @@ void cmSourceFile::DefineProperties(cmake *cm)
      "Additional dependencies that should be checked as part of "
      "building this source file.");
 
+  cm->DefineProperty
+    ("OBJECT_OUTPUTS", cmProperty::SOURCE_FILE, 
+     "Additional outputs for a Makefile rule.",
+     "Additional outputs created by compilation of this source file. "
+     "If any of these outputs is missing the object will be recompiled. "
+     "This is supported only on Makefile generators and will be ignored "
+     "on other generators.");
+
   cm->DefineProperty
     ("SYMBOLIC", cmProperty::SOURCE_FILE, 
      "Is this just a name for a rule.",

Tests/PrecompiledHeader/CMakeLists.txt

@@ -13,14 +13,13 @@ ELSE(CMAKE_CONFIGURATION_TYPES)
 ENDIF(CMAKE_CONFIGURATION_TYPES)
 FILE(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/PCH)
 
-# The VS6 IDE does not support renaming .pch files so we cannot use a
-# separate target.
+# The VS6 IDE does not support renaming .pch files with /Fp.
 IF("${CMAKE_GENERATOR}" MATCHES "Visual Studio 6")
-  SET(PCH_USE_TARGET 0)
   SET(PCH_USE_INCLUDE_DIR 1)
+  SET(PCH_FILE)
 ELSE("${CMAKE_GENERATOR}" MATCHES "Visual Studio 6")
-  SET(PCH_USE_TARGET 1)
   SET(PCH_USE_INCLUDE_DIR 0)
+  SET(PCH_FILE "\"/Fp${PCH_DIR}/foo_precompiled.pch\"")
 ENDIF("${CMAKE_GENERATOR}" MATCHES "Visual Studio 6")
 
 # Choose between an explicit include path and using /I during
@@ -34,37 +33,22 @@ ENDIF(PCH_USE_INCLUDE_DIR)
 
 # Create a target that will use a precompiled header.
 SET(foo_SRCS foo1.c foo2.c)
-IF(PCH_USE_TARGET)
-  ADD_EXECUTABLE(foo ${foo_SRCS})
+ADD_EXECUTABLE(foo foo_precompile.c ${foo_SRCS})
 
-  # Create a target to precompile the header for the executable.
-  ADD_LIBRARY(foo_precompile foo_precompile.c include/foo_precompiled.h)
-  SET_TARGET_PROPERTIES(foo_precompile PROPERTIES OUTPUT_NAME foo)
-  ADD_DEPENDENCIES(foo foo_precompile)
+# Setup flags on the target to create and use the precompiled header.
+SET_TARGET_PROPERTIES(foo PROPERTIES
+  COMPILE_FLAGS "/Yufoo_precompiled.h /FIfoo_precompiled.h ${PCH_FILE}")
+SET_SOURCE_FILES_PROPERTIES(foo_precompile.c PROPERTIES
+  COMPILE_FLAGS "/Ycfoo_precompiled.h ${PCH_INCLUDE_DIR}")
 
-  SET(PCH_TARGETS foo foo_precompile)
-  SET(PCH_FILE "\"/Fp${PCH_DIR}/foo_precompiled.pch\"")
-ELSE(PCH_USE_TARGET)
-  # Put the precompiled header source directly in the target.
-  ADD_EXECUTABLE(foo foo_precompile.c ${foo_SRCS})
-  SET(PCH_TARGETS foo)
-ENDIF(PCH_USE_TARGET)
-
-# Add the PCH to the list of files to clean.  It is created as a
-# side-effect so CMake does not know about it.
-SET_DIRECTORY_PROPERTIES(PROPERTIES
-  ADDITIONAL_MAKE_CLEAN_FILES ${PCH_DIR}/foo_precompiled.pch
-  )
-
-# Setup flags on the two targets to create and use the precompiled header.
-SET_TARGET_PROPERTIES(${PCH_TARGETS} PROPERTIES COMPILE_FLAGS
-  "/Yufoo_precompiled.h /FIfoo_precompiled.h ${PCH_FILE}")
-SET_SOURCE_FILES_PROPERTIES(foo_precompile.c PROPERTIES COMPILE_FLAGS
-  "/Ycfoo_precompiled.h ${PCH_INCLUDE_DIR}")
-
-# Make sure the object files rebuild when their precompiled header has changed.
-# The VS IDE takes care of this automatically.
+# Setup dependencies for precompiled header creation and use.  The VS
+# IDE takes care of this automatically.
 IF("${CMAKE_GENERATOR}" MATCHES "Makefile")
+  # This source file creates the precompiled header as a side-effect.
+  SET_SOURCE_FILES_PROPERTIES(foo_precompile.c PROPERTIES
+    OBJECT_OUTPUTS "${PCH_DIR}/foo_precompiled.pch")
+
+  # These source files use the precompiled header.
   SET_SOURCE_FILES_PROPERTIES(${foo_SRCS} PROPERTIES
     OBJECT_DEPENDS "${PCH_DIR}/foo_precompiled.pch")
 ENDIF("${CMAKE_GENERATOR}" MATCHES "Makefile")