CMP0065: Restrict the use of CMAKE_SHARED_LIBRARY_LINK_<LANG>_FLAGS

This new policy restricts the addition of the shared library link flags
to executables only when the ENABLE_EXPORTS property is set to True.

4 files changed, 46 insertions, 6 deletions

diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 4418ead..6c7b194 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -1540,13 +1540,47 @@ void cmLocalGenerator::OutputLinkLibraries(std::string& linkLibraries,
     this->Makefile->GetSafeDefinition("CMAKE_LIBRARY_PATH_TERMINATOR");
 
   // Flags to link an executable to shared libraries.
-  std::string linkFlagsVar = "CMAKE_SHARED_LIBRARY_LINK_";
-  linkFlagsVar += linkLanguage;
-  linkFlagsVar += "_FLAGS";
   if( tgt.GetType() == cmTarget::EXECUTABLE )
     {
-    linkLibs = this->Makefile->GetSafeDefinition(linkFlagsVar);
-    linkLibs += " ";
+    bool add_shlib_flags = false;
+    switch(tgt.Target->GetPolicyStatusCMP0065())
+      {
+      case cmPolicies::WARN:
+        if(!tgt.GetPropertyAsBool("ENABLE_EXPORTS") &&
+           this->Makefile->PolicyOptionalWarningEnabled(
+             "CMAKE_POLICY_WARNING_CMP0065"))
+          {
+          std::ostringstream w;
+          w << cmPolicies::GetPolicyWarning(cmPolicies::CMP0065) << "\n"
+            "For compatibility with older versions of CMake, "
+            "additional flags may be added to export symbols on all "
+            "executables regardless of thier ENABLE_EXPORTS property.";
+          this->Makefile->IssueMessage(cmake::AUTHOR_WARNING, w.str());
+          }
+      case cmPolicies::OLD:
+        // OLD behavior is to always add the flags
+        add_shlib_flags = true;
+        break;
+      case cmPolicies::REQUIRED_IF_USED:
+      case cmPolicies::REQUIRED_ALWAYS:
+        this->Makefile->IssueMessage(
+          cmake::FATAL_ERROR,
+          cmPolicies::GetRequiredPolicyError(cmPolicies::CMP0065)
+          );
+      case cmPolicies::NEW:
+        // NEW behavior is to only add the flags if ENABLE_EXPORTS is on
+        add_shlib_flags = tgt.GetPropertyAsBool("ENABLE_EXPORTS");
+        break;
+      }
+
+    if(add_shlib_flags)
+      {
+      std::string linkFlagsVar = "CMAKE_SHARED_LIBRARY_LINK_";
+      linkFlagsVar += linkLanguage;
+      linkFlagsVar += "_FLAGS";
+      linkLibs = this->Makefile->GetSafeDefinition(linkFlagsVar);
+      linkLibs += " ";
+      }
     }
 
   // Append the framework search path flags.
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index b20c7a9..283f277 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -220,6 +220,10 @@ class cmPolicy;
     3, 3, 0, cmPolicies::WARN) \
   SELECT(POLICY, CMP0064, \
     "Support new TEST if() operator.", \
+    3, 4, 0, cmPolicies::WARN) \
+  SELECT(POLICY, CMP0065, \
+    "Do not add flags to export symbols from executables without " \
+    "the ENABLE_EXPORTS target property.", \
     3, 4, 0, cmPolicies::WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 13e0d7e..bb44956 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -347,6 +347,7 @@ void cmTarget::SetMakefile(cmMakefile* mf)
     {
     this->SetPropertyDefault("ANDROID_GUI", 0);
     this->SetPropertyDefault("CROSSCOMPILING_EMULATOR", 0);
+    this->SetPropertyDefault("ENABLE_EXPORTS", 0);
     }
   if(this->TargetTypeValue == cmTarget::SHARED_LIBRARY
       || this->TargetTypeValue == cmTarget::MODULE_LIBRARY)
diff --git a/Source/cmTarget.h b/Source/cmTarget.h
index c86ec24..3e71dbd 100644
--- a/Source/cmTarget.h
+++ b/Source/cmTarget.h
@@ -41,7 +41,8 @@
   F(CMP0046) \
   F(CMP0052) \
   F(CMP0060) \
-  F(CMP0063)
+  F(CMP0063) \
+  F(CMP0065)
 
 class cmake;
 class cmMakefile;