Automatically link to the qtmain library when linking to QtCore.

When using QAxServer, ensure that the qtmain library is excluded
by reporting an error at CMake time if it is not.

5 files changed, 35 insertions, 2 deletions

diff --git a/Source/cmGeneratorExpressionEvaluator.cxx b/Source/cmGeneratorExpressionEvaluator.cxx
index 2ddc058..c791977 100644
--- a/Source/cmGeneratorExpressionEvaluator.cxx
+++ b/Source/cmGeneratorExpressionEvaluator.cxx
@@ -492,6 +492,7 @@ static const char* targetPolicyWhitelist[] = {
     "CMP0003"
   , "CMP0004"
   , "CMP0008"
+  , "CMP0020"
 };
 
 cmPolicies::PolicyStatus statusForTarget(cmTarget *tgt, const char *policy)
@@ -505,6 +506,7 @@ cmPolicies::PolicyStatus statusForTarget(cmTarget *tgt, const char *policy)
   RETURN_POLICY(CMP0003)
   RETURN_POLICY(CMP0004)
   RETURN_POLICY(CMP0008)
+  RETURN_POLICY(CMP0020)
 
 #undef RETURN_POLICY
 
@@ -523,6 +525,7 @@ cmPolicies::PolicyID policyForString(const char *policy_id)
   RETURN_POLICY_ID(CMP0003)
   RETURN_POLICY_ID(CMP0004)
   RETURN_POLICY_ID(CMP0008)
+  RETURN_POLICY_ID(CMP0020)
 
 #undef RETURN_POLICY_ID
 
@@ -575,8 +578,8 @@ static const struct TargetPolicyNode : public cmGeneratorExpressionNode
       }
     reportError(context, content->GetOriginalExpression(),
       "$<TARGET_POLICY:prop> may only be used with a limited number of "
-      "policies.  Currently it may be used with policies CMP0003, CMP0004 "
-      "and CMP0008."
+      "policies.  Currently it may be used with policies CMP0003, CMP0004, "
+      "CMP0008 and CMP0020."
       );
     return std::string();
   }
diff --git a/Source/cmPolicies.cxx b/Source/cmPolicies.cxx
index eb7d666..831e92e 100644
--- a/Source/cmPolicies.cxx
+++ b/Source/cmPolicies.cxx
@@ -508,6 +508,27 @@ cmPolicies::cmPolicies()
     "for strict compatibility.  "
     "The NEW behavior for this policy is to leave the values untouched.",
     2,8,11,0, cmPolicies::WARN);
+
+  this->DefinePolicy(
+    CMP0020, "CMP0020",
+    "Automatically link Qt executables to qtmain target on Windows.",
+    "CMake 2.8.10 and lower required users of Qt to always specify a link "
+    "dependency to the qtmain.lib static library manually on Windows.  CMake "
+    "2.8.11 gained the ability to evaluate generator expressions while "
+    "determining the link dependencies from IMPORTED targets.  This allows "
+    "CMake itself to automatically link executables which link to Qt to the "
+    "qtmain.lib library when using IMPORTED Qt targets.  For applications "
+    "already linking to qtmain.lib, this should have little impact.  For "
+    "applications which supply their own alternative WinMain implementation "
+    "and for applications which use the QAxServer library, this automatic "
+    "linking will need to be disabled as per the documentation."
+    "\n"
+    "The OLD behavior for this policy is not to link executables to "
+    "qtmain.lib automatically when they link to the QtCore IMPORTED"
+    "target.  "
+    "The NEW behavior for this policy is to link executables to "
+    "qtmain.lib automatically when they link to QtCore IMPORTED target.",
+    2,8,11,0, cmPolicies::WARN);
 }
 
 cmPolicies::~cmPolicies()
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index d7d945c..c11af07 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -69,6 +69,7 @@ public:
     /// POSITION_INDEPENDENT_CODE property and *_COMPILE_OPTIONS_PI{E,C}
     /// instead.
     CMP0019, ///< No variable re-expansion in include and link info
+    CMP0020, ///< Automatically link Qt executables to qtmain target
 
     /** \brief Always the last entry.
      *
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 45862fb..d1bd4a6 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -145,6 +145,7 @@ cmTarget::cmTarget()
   this->PolicyStatusCMP0003 = cmPolicies::WARN;
   this->PolicyStatusCMP0004 = cmPolicies::WARN;
   this->PolicyStatusCMP0008 = cmPolicies::WARN;
+  this->PolicyStatusCMP0020 = cmPolicies::WARN;
   this->LinkLibrariesAnalyzed = false;
   this->HaveInstallRule = false;
   this->DLLPlatform = false;
@@ -1499,6 +1500,8 @@ void cmTarget::SetMakefile(cmMakefile* mf)
     this->Makefile->GetPolicyStatus(cmPolicies::CMP0004);
   this->PolicyStatusCMP0008 =
     this->Makefile->GetPolicyStatus(cmPolicies::CMP0008);
+  this->PolicyStatusCMP0020 =
+    this->Makefile->GetPolicyStatus(cmPolicies::CMP0020);
 }
 
 //----------------------------------------------------------------------------
diff --git a/Source/cmTarget.h b/Source/cmTarget.h
index 69a00c1..ea3b823 100644
--- a/Source/cmTarget.h
+++ b/Source/cmTarget.h
@@ -102,6 +102,10 @@ public:
   cmPolicies::PolicyStatus GetPolicyStatusCMP0008() const
     { return this->PolicyStatusCMP0008; }
 
+  /** Get the status of policy CMP0020 when the target was created.  */
+  cmPolicies::PolicyStatus GetPolicyStatusCMP0020() const
+    { return this->PolicyStatusCMP0020; }
+
   /**
    * Get the list of the custom commands for this target
    */
@@ -656,6 +660,7 @@ private:
   cmPolicies::PolicyStatus PolicyStatusCMP0003;
   cmPolicies::PolicyStatus PolicyStatusCMP0004;
   cmPolicies::PolicyStatus PolicyStatusCMP0008;
+  cmPolicies::PolicyStatus PolicyStatusCMP0020;
 
   // Internal representation details.
   friend class cmTargetInternals;