Add the ALIAS target concept for libraries and executables.

* The ALIAS name must match a validity regex.
* Executables and libraries may be aliased.
* An ALIAS acts immutable. It can not be used as the lhs
  of target_link_libraries or other commands.
* An ALIAS can be used with add_custom_command, add_custom_target,
  and add_test in the same way regular targets can.
* The target of an ALIAS can be retrieved with the ALIASED_TARGET
  target property.
* An ALIAS does not appear in the generated buildsystem. It
  is kept separate from cmMakefile::Targets for that reason.
* A target may have multiple aliases.
* An ALIAS target may not itself have an alias.
* An IMPORTED target may not have an alias.
* An ALIAS may not be exported or imported.

1 files changed, 46 insertions, 4 deletions

diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 1920cc0..aae92dd 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -41,6 +41,7 @@
 
 #include <stack>
 #include <ctype.h> // for isspace
+#include <assert.h>
 
 class cmMakefile::Internals
 {
@@ -1437,6 +1438,14 @@ void cmMakefile::AddLinkDirectoryForTarget(const char *target,
   cmTargets::iterator i = this->Targets.find(target);
   if ( i != this->Targets.end())
     {
+    if(this->IsAlias(target))
+      {
+      cmOStringStream e;
+      e << "ALIAS target \"" << target << "\" "
+        << "may not be linked into another target.";
+      this->IssueMessage(cmake::FATAL_ERROR, e.str().c_str());
+      return;
+      }
     i->second.AddLinkDirectory( d );
     }
   else
@@ -1923,6 +1932,12 @@ void cmMakefile::AddGlobalLinkInformation(const char* name, cmTarget& target)
 }
 
 
+void cmMakefile::AddAlias(const char* lname, cmTarget *tgt)
+{
+  this->AliasTargets[lname] = tgt;
+  this->LocalGenerator->GetGlobalGenerator()->AddAlias(lname, tgt);
+}
+
 cmTarget* cmMakefile::AddLibrary(const char* lname, cmTarget::TargetType type,
                             const std::vector<std::string> &srcs,
                             bool excludeFromAll)
@@ -3758,8 +3773,17 @@ const char* cmMakefile::GetFeature(const char* feature, const char* config)
   return 0;
 }
 
-cmTarget* cmMakefile::FindTarget(const char* name)
+cmTarget* cmMakefile::FindTarget(const char* name, bool excludeAliases)
 {
+  if (!excludeAliases)
+    {
+    std::map<std::string, cmTarget*>::iterator i
+                                              = this->AliasTargets.find(name);
+    if (i != this->AliasTargets.end())
+      {
+      return i->second;
+      }
+    }
   cmTargets& tgts = this->GetTargets();
 
   cmTargets::iterator i = tgts.find ( name );
@@ -4184,7 +4208,7 @@ cmMakefile::AddImportedTarget(const char* name, cmTarget::TargetType type,
 }
 
 //----------------------------------------------------------------------------
-cmTarget* cmMakefile::FindTargetToUse(const char* name)
+cmTarget* cmMakefile::FindTargetToUse(const char* name, bool excludeAliases)
 {
   // Look for an imported target.  These take priority because they
   // are more local in scope and do not have to be globally unique.
@@ -4196,15 +4220,25 @@ cmTarget* cmMakefile::FindTargetToUse(const char* name)
     }
 
   // Look for a target built in this directory.
-  if(cmTarget* t = this->FindTarget(name))
+  if(cmTarget* t = this->FindTarget(name, excludeAliases))
     {
     return t;
     }
 
   // Look for a target built in this project.
-  return this->LocalGenerator->GetGlobalGenerator()->FindTarget(0, name);
+  return this->LocalGenerator->GetGlobalGenerator()->FindTarget(0, name,
+                                                              excludeAliases);
 }
 
+//----------------------------------------------------------------------------
+bool cmMakefile::IsAlias(const char *name)
+{
+  if (this->AliasTargets.find(name) != this->AliasTargets.end())
+    return true;
+  return this->GetLocalGenerator()->GetGlobalGenerator()->IsAlias(name);
+}
+
+//----------------------------------------------------------------------------
 cmGeneratorTarget* cmMakefile::FindGeneratorTargetToUse(const char* name)
 {
   cmTarget *t = this->FindTargetToUse(name);
@@ -4215,6 +4249,14 @@ cmGeneratorTarget* cmMakefile::FindGeneratorTargetToUse(const char* name)
 bool cmMakefile::EnforceUniqueName(std::string const& name, std::string& msg,
                                    bool isCustom)
 {
+  if(this->IsAlias(name.c_str()))
+    {
+    cmOStringStream e;
+    e << "cannot create target \"" << name
+      << "\" because an alias with the same name already exists.";
+    msg = e.str();
+    return false;
+    }
   if(cmTarget* existing = this->FindTargetToUse(name.c_str()))
     {
     // The name given conflicts with an existing target.  Produce an