cmTarget: Make the SOURCES origin tracable.

Help/variable/CMAKE_DEBUG_TARGET_PROPERTIES.rst

@@ -6,7 +6,8 @@ Enables tracing output for target properties.
 This variable can be populated with a list of properties to generate
 debug output for when evaluating target properties.  Currently it can
 only be used when evaluating the :prop_tgt:`INCLUDE_DIRECTORIES`,
-:prop_tgt:`COMPILE_DEFINITIONS`, :prop_tgt:`COMPILE_OPTIONS`, :prop_tgt:`AUTOUIC_OPTIONS`,
+:prop_tgt:`COMPILE_DEFINITIONS`, :prop_tgt:`COMPILE_OPTIONS`,
+:prop_tgt:`AUTOUIC_OPTIONS`, :prop_tgt:`SOURCES`,
 :prop_tgt:`POSITION_INDEPENDENT_CODE` target properties and any other property
 listed in :prop_tgt:`COMPATIBLE_INTERFACE_STRING` and other ``COMPATIBLE_INTERFACE_``
 properties.  It outputs an origin for each entry in the target property.

Source/cmTarget.cxx

@@ -224,6 +224,7 @@ cmTarget::cmTarget()
   this->DebugIncludesDone = false;
   this->DebugCompileOptionsDone = false;
   this->DebugCompileDefinitionsDone = false;
+  this->DebugSourcesDone = false;
 }
 
 //----------------------------------------------------------------------------
@@ -553,7 +554,7 @@ static void processSources(cmTarget const* tgt,
       std::set<std::string> &uniqueSrcs,
       cmGeneratorExpressionDAGChecker *dagChecker,
       cmTarget const* head,
-      std::string const& config)
+      std::string const& config, bool debugSources)
 {
   cmMakefile *mf = tgt->GetMakefile();
 
@@ -601,6 +602,7 @@ static void processSources(cmTarget const* tgt,
         (*it)->CachedEntries = entrySources;
         }
       }
+    std::string usedSources;
     for(std::vector<std::string>::iterator
           li = entrySources.begin(); li != entrySources.end(); ++li)
       {
@@ -609,9 +611,20 @@ static void processSources(cmTarget const* tgt,
       if(uniqueSrcs.insert(src).second)
         {
         srcs.push_back(src);
+        if (debugSources)
+          {
+          usedSources += " * " + src + "\n";
           }
         }
       }
+    if (!usedSources.empty())
+      {
+      mf->GetCMakeInstance()->IssueMessage(cmake::LOG,
+                            std::string("Used sources for target ")
+                            + tgt->GetName() + ":\n"
+                            + usedSources, (*it)->ge->GetBacktrace());
+      }
+    }
 }
 
 //----------------------------------------------------------------------------
@@ -621,6 +634,24 @@ void cmTarget::GetSourceFiles(std::vector<std::string> &files,
 {
   assert(this->GetType() != INTERFACE_LIBRARY);
 
+  std::vector<std::string> debugProperties;
+  const char *debugProp =
+              this->Makefile->GetDefinition("CMAKE_DEBUG_TARGET_PROPERTIES");
+  if (debugProp)
+    {
+    cmSystemTools::ExpandListArgument(debugProp, debugProperties);
+    }
+
+  bool debugSources = !this->DebugSourcesDone
+                    && std::find(debugProperties.begin(),
+                                 debugProperties.end(),
+                                 "SOURCES")
+                        != debugProperties.end();
+
+  if (this->Makefile->IsGeneratingBuildSystem())
+    {
+    this->DebugSourcesDone = true;
+    }
 
   cmListFileBacktrace lfbt;
 
@@ -635,7 +666,8 @@ void cmTarget::GetSourceFiles(std::vector<std::string> &files,
                  uniqueSrcs,
                  &dagChecker,
                  head,
-                 config);
+                 config,
+                 debugSources);
 
   if (!this->Internal->CacheLinkInterfaceSourcesDone[config])
     {
@@ -686,7 +718,8 @@ void cmTarget::GetSourceFiles(std::vector<std::string> &files,
                             uniqueSrcs,
                             &dagChecker,
                             head,
-                            config);
+                            config,
+                            debugSources);
 
   if (!this->Makefile->IsGeneratingBuildSystem())
     {

Source/cmTarget.h

@@ -710,6 +710,7 @@ private:
   mutable std::map<std::string, bool> DebugCompatiblePropertiesDone;
   mutable bool DebugCompileOptionsDone;
   mutable bool DebugCompileDefinitionsDone;
+  mutable bool DebugSourcesDone;
   mutable std::set<std::string> LinkImplicitNullProperties;
   bool BuildInterfaceIncludesAppended;
 

Tests/RunCMake/TargetSources/OriginDebug-result.txt

@@ -0,0 +1 @@
+0

Tests/RunCMake/TargetSources/OriginDebug-stderr.txt

@@ -0,0 +1,15 @@
+CMake Debug Log at OriginDebug.cmake:13 \(add_library\):
+  Used sources for target OriginDebug:
+
+   \* .*Tests/RunCMake/TargetSources/empty_2.cpp
+
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
++
+CMake Debug Log at OriginDebug.cmake:14 \(target_link_libraries\):
+  Used sources for target OriginDebug:
+
+   \* .*Tests/RunCMake/TargetSources/empty_1.cpp
+
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/TargetSources/OriginDebug.cmake

@@ -0,0 +1,14 @@
+
+cmake_minimum_required(VERSION 3.0)
+
+project(OriginDebug)
+
+set(CMAKE_DEBUG_TARGET_PROPERTIES SOURCES)
+
+add_library(iface INTERFACE)
+set_property(TARGET iface PROPERTY INTERFACE_SOURCES
+  empty_1.cpp
+)
+
+add_library(OriginDebug empty_2.cpp)
+target_link_libraries(OriginDebug iface)

Tests/RunCMake/TargetSources/OriginDebugIDE-result.txt

@@ -0,0 +1 @@
+0

Tests/RunCMake/TargetSources/OriginDebugIDE-stderr.txt

@@ -0,0 +1,22 @@
+CMake Debug Log at OriginDebug.cmake:13 \(add_library\):
+  Used sources for target OriginDebug:
+
+   \* .*Tests/RunCMake/TargetSources/empty_2.cpp
+
+Call Stack \(most recent call first\):
+  OriginDebugIDE.cmake:4 \(include\)
+  CMakeLists.txt:3 \(include\)
++
+CMake Debug Log:
+  Used sources for target OriginDebug:
+
+   * .*CMakeLists.txt
++
+CMake Debug Log at OriginDebug.cmake:14 \(target_link_libraries\):
+  Used sources for target OriginDebug:
+
+   \* .*Tests/RunCMake/TargetSources/empty_1.cpp
+
+Call Stack \(most recent call first\):
+  OriginDebugIDE.cmake:4 \(include\)
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/TargetSources/OriginDebugIDE.cmake

@@ -0,0 +1,4 @@
+
+# Separate test for the IDEs, because they show the CMakeLists.txt file
+# as a source file.
+include(${CMAKE_CURRENT_LIST_DIR}/OriginDebug.cmake)

Tests/RunCMake/TargetSources/RunCMakeTest.cmake

@@ -3,4 +3,7 @@ include(RunCMake)
 if(RunCMake_GENERATOR MATCHES Xcode
     OR RunCMake_GENERATOR MATCHES "Visual Studio")
   run_cmake(ConfigNotAllowed)
+  run_cmake(OriginDebugIDE)
+else()
+  run_cmake(OriginDebug)
 endif()