Create make rules for INTERFACE_LIBRARY targets.

The result is that the depends of the target are created.

So,

 add_library(somelib foo.cpp)
 add_library(anotherlib EXCLUDE_FROM_ALL foo.cpp)
 add_library(extra EXCLUDE_FROM_ALL foo.cpp)
 target_link_libraries(anotherlib extra)

 add_library(iface INTERFACE)
 target_link_libraries(iface INTERFACE anotherlib)

Executing 'make iface' will result in the anotherlib and extra targets
being made.

Adding a regular executable to the INTERFACE of an INTERFACE_LIBRARY
will not result in the executable being built with 'make iface' because
of the logic in cmComputeTargetDepends::AddTargetDepend.

So far, this is implemented only for the Makefile generator. Other
generators will follow if this feature is possible for them.

Make INTERFACE_LIBRARY targets part of the all target by default.
Test this by building the all target and making the expected library
EXCLUDE_FROM_ALL.

7 files changed, 95 insertions, 38 deletions

diff --git a/Source/cmComputeTargetDepends.cxx b/Source/cmComputeTargetDepends.cxx
index 0829add..7fd4754 100644
--- a/Source/cmComputeTargetDepends.cxx
+++ b/Source/cmComputeTargetDepends.cxx
@@ -208,7 +208,15 @@ void cmComputeTargetDepends::CollectTargetDepends(int depender_index)
   std::set<cmStdString> emitted;
   {
   std::vector<std::string> tlibs;
-  depender->GetDirectLinkLibraries(0, tlibs, depender);
+  if (depender->GetType() == cmTarget::INTERFACE_LIBRARY)
+    {
+    // For INTERFACE_LIBRARY depend on the interface instead.
+    depender->GetInterfaceLinkLibraries(0, tlibs, depender);
+    }
+  else
+    {
+    depender->GetDirectLinkLibraries(0, tlibs, depender);
+    }
   // A target should not depend on itself.
   emitted.insert(depender->GetName());
   for(std::vector<std::string>::const_iterator lib = tlibs.begin();
diff --git a/Source/cmGlobalUnixMakefileGenerator3.cxx b/Source/cmGlobalUnixMakefileGenerator3.cxx
index 7ab107f..ce95c08 100644
--- a/Source/cmGlobalUnixMakefileGenerator3.cxx
+++ b/Source/cmGlobalUnixMakefileGenerator3.cxx
@@ -435,6 +435,7 @@ cmGlobalUnixMakefileGenerator3
        (l->second.GetType() == cmTarget::SHARED_LIBRARY) ||
        (l->second.GetType() == cmTarget::MODULE_LIBRARY) ||
        (l->second.GetType() == cmTarget::OBJECT_LIBRARY) ||
+       (l->second.GetType() == cmTarget::INTERFACE_LIBRARY) ||
        (l->second.GetType() == cmTarget::UTILITY))
       {
       // Add this to the list of depends rules in this directory.
@@ -612,6 +613,7 @@ cmGlobalUnixMakefileGenerator3
           (t->second.GetType() == cmTarget::SHARED_LIBRARY) ||
           (t->second.GetType() == cmTarget::MODULE_LIBRARY) ||
           (t->second.GetType() == cmTarget::OBJECT_LIBRARY) ||
+          (t->second.GetType() == cmTarget::INTERFACE_LIBRARY) ||
           (t->second.GetType() == cmTarget::UTILITY)))
         {
         // Add a rule to build the target by name.
@@ -633,6 +635,10 @@ cmGlobalUnixMakefileGenerator3
                           t->second.GetName(), depends, commands,
                           true);
 
+        if (t->second.GetType() == cmTarget::INTERFACE_LIBRARY)
+          {
+          continue;
+          }
         // Add a fast rule to build the target
         std::string localName = lg->GetRelativeTargetDirectory(t->second);
         std::string makefileName;
@@ -699,6 +705,7 @@ cmGlobalUnixMakefileGenerator3
         || (t->second.GetType() == cmTarget::SHARED_LIBRARY)
         || (t->second.GetType() == cmTarget::MODULE_LIBRARY)
         || (t->second.GetType() == cmTarget::OBJECT_LIBRARY)
+        || (t->second.GetType() == cmTarget::INTERFACE_LIBRARY)
         || (t->second.GetType() == cmTarget::UTILITY)))
       {
       std::string makefileName;
@@ -715,53 +722,64 @@ cmGlobalUnixMakefileGenerator3
         << localName << "\n\n";
 
       commands.clear();
-      makeTargetName = localName;
-      makeTargetName += "/depend";
-      commands.push_back(lg->GetRecursiveMakeCall
-                         (makefileName.c_str(),makeTargetName.c_str()));
 
-      // add requires if we need it for this generator
-      if (needRequiresStep)
+      if(t->second.GetType() != cmTarget::INTERFACE_LIBRARY)
         {
         makeTargetName = localName;
-        makeTargetName += "/requires";
+        makeTargetName += "/depend";
         commands.push_back(lg->GetRecursiveMakeCall
-                           (makefileName.c_str(),makeTargetName.c_str()));
-        }
-      makeTargetName = localName;
-      makeTargetName += "/build";
-      commands.push_back(lg->GetRecursiveMakeCall
                           (makefileName.c_str(),makeTargetName.c_str()));
 
-      // Write the rule.
-      localName += "/all";
-      depends.clear();
+        // add requires if we need it for this generator
+        if (needRequiresStep)
+          {
+          makeTargetName = localName;
+          makeTargetName += "/requires";
+          commands.push_back(lg->GetRecursiveMakeCall
+                            (makefileName.c_str(),makeTargetName.c_str()));
+          }
+        makeTargetName = localName;
+        makeTargetName += "/build";
+        commands.push_back(lg->GetRecursiveMakeCall
+                            (makefileName.c_str(),makeTargetName.c_str()));
 
-      std::string progressDir =
-        lg->GetMakefile()->GetHomeOutputDirectory();
-      progressDir += cmake::GetCMakeFilesDirectory();
-        {
-        cmOStringStream progCmd;
-        progCmd << "$(CMAKE_COMMAND) -E cmake_progress_report ";
-        // all target counts
-        progCmd << lg->Convert(progressDir.c_str(),
-                                cmLocalGenerator::FULL,
-                                cmLocalGenerator::SHELL);
-        progCmd << " ";
-        std::vector<unsigned long>& progFiles =
-          this->ProgressMap[&t->second].Marks;
-        for (std::vector<unsigned long>::iterator i = progFiles.begin();
-              i != progFiles.end(); ++i)
+        // Write the rule.
+        localName += "/all";
+        depends.clear();
+
+        std::string progressDir =
+          lg->GetMakefile()->GetHomeOutputDirectory();
+        progressDir += cmake::GetCMakeFilesDirectory();
           {
-          progCmd << " " << *i;
+          cmOStringStream progCmd;
+          progCmd << "$(CMAKE_COMMAND) -E cmake_progress_report ";
+          // all target counts
+          progCmd << lg->Convert(progressDir.c_str(),
+                                  cmLocalGenerator::FULL,
+                                  cmLocalGenerator::SHELL);
+          progCmd << " ";
+          std::vector<unsigned long>& progFiles =
+            this->ProgressMap[&t->second].Marks;
+          for (std::vector<unsigned long>::iterator i = progFiles.begin();
+                i != progFiles.end(); ++i)
+            {
+            progCmd << " " << *i;
+            }
+          commands.push_back(progCmd.str());
           }
-        commands.push_back(progCmd.str());
+        progressDir = "Built target ";
+        progressDir += t->first;
+        lg->AppendEcho(commands,progressDir.c_str());
+        }
+      else
+        {
+        depends.clear();
         }
-      progressDir = "Built target ";
-      progressDir += t->first;
-      lg->AppendEcho(commands,progressDir.c_str());
-
       this->AppendGlobalTargetDepends(depends,t->second);
+      if(depends.empty() && this->EmptyRuleHackDepends != "")
+        {
+        depends.push_back(this->EmptyRuleHackDepends);
+        }
       lg->WriteMakeRule(ruleFileStream, "All Build rule for target.",
                         localName.c_str(), depends, commands, true);
 
@@ -777,7 +795,7 @@ cmGlobalUnixMakefileGenerator3
 
       // Write the rule.
       commands.clear();
-      progressDir = lg->GetMakefile()->GetHomeOutputDirectory();
+      std::string progressDir = lg->GetMakefile()->GetHomeOutputDirectory();
       progressDir += cmake::GetCMakeFilesDirectory();
 
       {
diff --git a/Source/cmLocalUnixMakefileGenerator3.cxx b/Source/cmLocalUnixMakefileGenerator3.cxx
index dc401dc..508eca1 100644
--- a/Source/cmLocalUnixMakefileGenerator3.cxx
+++ b/Source/cmLocalUnixMakefileGenerator3.cxx
@@ -381,6 +381,7 @@ void cmLocalUnixMakefileGenerator3
        (t->second.GetType() == cmTarget::SHARED_LIBRARY) ||
        (t->second.GetType() == cmTarget::MODULE_LIBRARY) ||
        (t->second.GetType() == cmTarget::OBJECT_LIBRARY) ||
+       (t->second.GetType() == cmTarget::INTERFACE_LIBRARY) ||
        (t->second.GetType() == cmTarget::UTILITY))
       {
       emitted.insert(t->second.GetName());
diff --git a/Source/cmMakefileLibraryTargetGenerator.cxx b/Source/cmMakefileLibraryTargetGenerator.cxx
index ea9663f..29365a3 100644
--- a/Source/cmMakefileLibraryTargetGenerator.cxx
+++ b/Source/cmMakefileLibraryTargetGenerator.cxx
@@ -82,6 +82,9 @@ void cmMakefileLibraryTargetGenerator::WriteRuleFiles()
     case cmTarget::OBJECT_LIBRARY:
       this->WriteObjectLibraryRules();
       break;
+    case cmTarget::INTERFACE_LIBRARY:
+      // Nothing to do.
+      break;
     default:
       // If language is not known, this is an error.
       cmSystemTools::Error("Unknown Library Type");
diff --git a/Source/cmMakefileTargetGenerator.cxx b/Source/cmMakefileTargetGenerator.cxx
index 9ca9149..6770e10 100644
--- a/Source/cmMakefileTargetGenerator.cxx
+++ b/Source/cmMakefileTargetGenerator.cxx
@@ -75,6 +75,7 @@ cmMakefileTargetGenerator::New(cmTarget *tgt)
     case cmTarget::SHARED_LIBRARY:
     case cmTarget::MODULE_LIBRARY:
     case cmTarget::OBJECT_LIBRARY:
+    case cmTarget::INTERFACE_LIBRARY:
       result = new cmMakefileLibraryTargetGenerator(tgt);
       break;
     case cmTarget::UTILITY:
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 5e10e25..bd37a54 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -1112,6 +1112,29 @@ void cmTarget::GetDirectLinkLibraries(const char *config,
 }
 
 //----------------------------------------------------------------------------
+void cmTarget::GetInterfaceLinkLibraries(const char *config,
+                            std::vector<std::string> &libs, cmTarget *head)
+{
+  const char *prop = this->GetProperty("INTERFACE_LINK_LIBRARIES");
+  if (prop)
+    {
+    cmListFileBacktrace lfbt;
+    cmGeneratorExpression ge(lfbt);
+    const cmsys::auto_ptr<cmCompiledGeneratorExpression> cge = ge.Parse(prop);
+
+    cmGeneratorExpressionDAGChecker dagChecker(lfbt,
+                                        this->GetName(),
+                                        "INTERFACE_LINK_LIBRARIES", 0, 0);
+    cmSystemTools::ExpandListArgument(cge->Evaluate(this->Makefile,
+                                        config,
+                                        false,
+                                        head,
+                                        &dagChecker),
+                                      libs);
+    }
+}
+
+//----------------------------------------------------------------------------
 std::string cmTarget::GetDebugGeneratorExpressions(const std::string &value,
                                   cmTarget::LinkLibraryType llt)
 {
diff --git a/Source/cmTarget.h b/Source/cmTarget.h
index 3c36da7..e8f4e08 100644
--- a/Source/cmTarget.h
+++ b/Source/cmTarget.h
@@ -177,6 +177,9 @@ public:
   void GetDirectLinkLibraries(const char *config,
                               std::vector<std::string> &,
                               cmTarget *head);
+  void GetInterfaceLinkLibraries(const char *config,
+                              std::vector<std::string> &,
+                              cmTarget *head);
 
   /** Compute the link type to use for the given configuration.  */
   LinkLibraryType ComputeLinkType(const char* config);