Support building shared libraries or modules without soname (#13155)

Add a boolean target property NO_SONAME which may be used to disable
soname for the specified shared library or module even if the platform
supports it.  This property should be useful for private shared
libraries or various plugins which live in private directories and have
not been designed to be found or loaded globally.

Replace references to <CMAKE_SHARED_LIBRARY_SONAME_${LANG}_FLAG> and
hard-coded -install_name flags with a conditional <SONAME_FLAG> which is
expanded to the value of the CMAKE_SHARED_LIBRARY_SONAME_${LANG}_FLAG
definition as long as soname supports is enabled for the target in
question.  Keep expanding CMAKE_SHARED_LIBRARY_SONAME_${LANG}_FLAG in
rules in case third party projects still use it.  Such projects would
not yet use NO_SONAME so the adjacent <TARGET_SONAME> will always be
expanded.  Make <TARGET_INSTALLNAME_DIR> NO_SONAME aware as well.  Since
-install_name is soname on OS X, this should not be a problem if this
variable is expanded only if soname is enabled.

The Ninja generator performs rule variable substitution only once
globally per rule to put its own placeholders.  Final substitution is
performed by ninja at build time.  Therefore we cannot conditionally
replace the soname placeholders on a per-target basis.  Rather than
omitting $SONAME from rules.ninja, simply do not write its contents for
targets which have NO_SONAME.  Since 3 variables are affected by
NO_SONAME ($SONAME, $SONAME_FLAG, $INSTALLNAME_DIR), set them only if
soname is enabled.

9 files changed, 90 insertions, 46 deletions

diff --git a/Source/cmExportFileGenerator.cxx b/Source/cmExportFileGenerator.cxx
index c4f5dfb..eb19df5e 100644
--- a/Source/cmExportFileGenerator.cxx
+++ b/Source/cmExportFileGenerator.cxx
@@ -137,10 +137,20 @@ cmExportFileGenerator
       (mf->IsOn("WIN32") || mf->IsOn("CYGWIN") || mf->IsOn("MINGW"));
     if(!dll_platform)
       {
-      std::string soname = target->GetSOName(config);
-      std::string prop = "IMPORTED_SONAME";
+      std::string prop;
+      std::string value;
+      if(target->HasSOName(config))
+        {
+        prop = "IMPORTED_SONAME";
+        value = target->GetSOName(config);
+        }
+      else
+        {
+        prop = "IMPORTED_NO_SONAME";
+        value = "TRUE";
+        }
       prop += suffix;
-      properties[prop] = soname;
+      properties[prop] = value;
       }
     }
 
diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 13ede5d..6362d80 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -954,29 +954,27 @@ cmLocalGenerator::ExpandRuleVariable(std::string const& variable,
         }
       }
     }
-  if(replaceValues.TargetSOName)
+  if(variable == "TARGET_SONAME" || variable == "SONAME_FLAG" ||
+     variable == "TARGET_INSTALLNAME_DIR")
     {
-    if(variable == "TARGET_SONAME")
+    // All these variables depend on TargetSOName
+    if(replaceValues.TargetSOName)
       {
-      if(replaceValues.Language)
+      if(variable == "TARGET_SONAME")
         {
-        std::string name = "CMAKE_SHARED_LIBRARY_SONAME_";
-        name += replaceValues.Language;
-        name += "_FLAG";
-        if(this->Makefile->GetDefinition(name.c_str()))
-          {
-          return replaceValues.TargetSOName;
-          }
+        return replaceValues.TargetSOName;
+        }
+      if(variable == "SONAME_FLAG" && replaceValues.SONameFlag)
+        {
+        return replaceValues.SONameFlag;
+        }
+      if(replaceValues.TargetInstallNameDir &&
+         variable == "TARGET_INSTALLNAME_DIR")
+        {
+        return replaceValues.TargetInstallNameDir;
         }
-      return "";
-      }
-    }
-  if(replaceValues.TargetInstallNameDir)
-    {
-    if(variable == "TARGET_INSTALLNAME_DIR")
-      {
-      return replaceValues.TargetInstallNameDir;
       }
+    return "";
     }
   if(replaceValues.LinkLibraries)
     {
diff --git a/Source/cmLocalGenerator.h b/Source/cmLocalGenerator.h
index 3e93819..cb84a30 100644
--- a/Source/cmLocalGenerator.h
+++ b/Source/cmLocalGenerator.h
@@ -228,6 +228,7 @@ public:
     const char* ObjectDir;
     const char* Flags;
     const char* ObjectsQuoted;
+    const char* SONameFlag;
     const char* TargetSOName;
     const char* TargetInstallNameDir;
     const char* LinkFlags;
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index e7e5eda..e3ef1b8 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -2201,6 +2201,14 @@ bool cmMakefile::PlatformIs64Bit() const
   return false;
 }
 
+const char* cmMakefile::GetSONameFlag(const char* language) const
+{
+  std::string name = "CMAKE_SHARED_LIBRARY_SONAME_";
+  name += language;
+  name += "_FLAG";
+  return GetDefinition(name.c_str());
+}
+
 bool cmMakefile::CanIWriteThisFile(const char* fileName)
 {
   if ( !this->IsOn("CMAKE_DISABLE_SOURCE_CHANGES") )
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 960ba39..ebd5bcf 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -593,6 +593,9 @@ public:
   /** Return whether the target platform is 64-bit.  */
   bool PlatformIs64Bit() const;
 
+  /** Retrieve soname flag for the specified language if supported */
+  const char* GetSONameFlag(const char* language) const;
+
   /**
    * Get a list of preprocessor define flags.
    */
diff --git a/Source/cmMakefileLibraryTargetGenerator.cxx b/Source/cmMakefileLibraryTargetGenerator.cxx
index 38aa59d..db59ffd 100644
--- a/Source/cmMakefileLibraryTargetGenerator.cxx
+++ b/Source/cmMakefileLibraryTargetGenerator.cxx
@@ -714,7 +714,11 @@ void cmMakefileLibraryTargetGenerator::WriteLibraryRules
   std::string linkString = linklibs.str();
   vars.LinkLibraries = linkString.c_str();
   vars.ObjectsQuoted = buildObjs.c_str();
-  vars.TargetSOName= targetNameSO.c_str();
+  if (this->Target->HasSOName(this->ConfigName))
+    {
+    vars.SONameFlag = this->Makefile->GetSONameFlag(linkLanguage);
+    vars.TargetSOName= targetNameSO.c_str();
+    }
   vars.LinkFlags = linkFlags.c_str();
 
   // Compute the directory portion of the install_name setting.
diff --git a/Source/cmNinjaNormalTargetGenerator.cxx b/Source/cmNinjaNormalTargetGenerator.cxx
index 2bad32c..bb8bd3f 100644
--- a/Source/cmNinjaNormalTargetGenerator.cxx
+++ b/Source/cmNinjaNormalTargetGenerator.cxx
@@ -152,6 +152,7 @@ cmNinjaNormalTargetGenerator
                                                 cmLocalGenerator::SHELL);
     vars.ObjectDir = objdir.c_str();
     vars.Target = "$out";
+    vars.SONameFlag = "$SONAME_FLAG";
     vars.TargetSOName = "$SONAME";
     vars.TargetInstallNameDir = "$INSTALLNAME_DIR";
     vars.TargetPDB = "$TARGET_PDB";
@@ -366,17 +367,20 @@ void cmNinjaNormalTargetGenerator::WriteLinkStatement()
                              this->GetTarget(),
                              this->TargetLinkLanguage,
                              this->GetConfigName());
-  vars["SONAME"] = this->TargetNameSO;
-
-  if (targetType == cmTarget::SHARED_LIBRARY) {
-    std::string install_name_dir =
-      this->GetTarget()->GetInstallNameDirForBuildTree(this->GetConfigName());
-
-    if (!install_name_dir.empty()) {
-      vars["INSTALLNAME_DIR"] =
-        this->GetLocalGenerator()->Convert(install_name_dir.c_str(),
-            cmLocalGenerator::NONE,
-            cmLocalGenerator::SHELL, false);
+  if (this->GetTarget()->HasSOName(this->GetConfigName())) {
+    vars["SONAME_FLAG"] =
+      this->GetMakefile()->GetSONameFlag(this->TargetLinkLanguage);
+    vars["SONAME"] = this->TargetNameSO;
+    if (targetType == cmTarget::SHARED_LIBRARY) {
+      std::string install_name_dir = this->GetTarget()
+        ->GetInstallNameDirForBuildTree(this->GetConfigName());
+
+      if (!install_name_dir.empty()) {
+        vars["INSTALLNAME_DIR"] =
+          this->GetLocalGenerator()->Convert(install_name_dir.c_str(),
+              cmLocalGenerator::NONE,
+              cmLocalGenerator::SHELL, false);
+      }
     }
   }
 
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index cfa9976..4789197 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -823,6 +823,19 @@ void cmTarget::DefineProperties(cmake *cm)
      "CMAKE_SKIP_BUILD_RPATH if it is set when a target is created.");
 
   cm->DefineProperty
+    ("NO_SONAME", cmProperty::TARGET,
+     "Whether to set \"soname\" when linking a shared library or module.",
+     "Enable this boolean property if a generated shared library or module "
+     "should not have \"soname\" set. Default is to set \"soname\" on all "
+     "shared libraries and modules as long as the platform supports it. "
+     "Generally, use this property only for leaf private libraries or "
+     "plugins. If you use it on normal shared libraries which other targets "
+     "link against, on some platforms a linker will insert a full path to "
+     "the library (as specified at link time) into the dynamic section of "
+     "the dependant binary. Therefore, once installed, dynamic linker may "
+     "eventually fail to locate the library for the binary.");
+
+  cm->DefineProperty
     ("SOVERSION", cmProperty::TARGET,
      "What version number is this target.",
      "For shared libraries VERSION and SOVERSION can be used to specify "
@@ -831,6 +844,7 @@ void cmTarget::DefineProperties(cmake *cm)
      "supports symlinks and the linker supports so-names. "
      "If only one of both is specified the missing is assumed to have "
      "the same version number. "
+     "SOVERSION is ignored if NO_SONAME property is set. "
      "For shared libraries and executables on Windows the VERSION "
      "attribute is parsed to extract a \"major.minor\" version number. "
      "These numbers are used as the image version of the binary. ");
@@ -2995,6 +3009,17 @@ std::string cmTarget::GetPDBName(const char* config)
 }
 
 //----------------------------------------------------------------------------
+bool cmTarget::HasSOName(const char* config)
+{
+  // soname is supported only for shared libraries and modules,
+  // and then only when the platform supports an soname flag.
+  return ((this->GetType() == cmTarget::SHARED_LIBRARY ||
+           this->GetType() == cmTarget::MODULE_LIBRARY) &&
+          !this->GetPropertyAsBool("NO_SONAME") &&
+          this->Makefile->GetSONameFlag(this->GetLinkerLanguage(config)));
+}
+
+//----------------------------------------------------------------------------
 std::string cmTarget::GetSOName(const char* config)
 {
   if(this->IsImported())
@@ -3327,22 +3352,10 @@ void cmTarget::GetLibraryNames(std::string& name,
     return;
     }
 
-  // Construct the name of the soname flag variable for this language.
-  const char* ll = this->GetLinkerLanguage(config);
-  std::string sonameFlag = "CMAKE_SHARED_LIBRARY_SONAME";
-  if(ll)
-    {
-    sonameFlag += "_";
-    sonameFlag += ll;
-    }
-  sonameFlag += "_FLAG";
-
   // Check for library version properties.
   const char* version = this->GetProperty("VERSION");
   const char* soversion = this->GetProperty("SOVERSION");
-  if((this->GetType() != cmTarget::SHARED_LIBRARY &&
-      this->GetType() != cmTarget::MODULE_LIBRARY) ||
-     !this->Makefile->GetDefinition(sonameFlag.c_str()) ||
+  if(!this->HasSOName(config) ||
      this->IsFrameworkOnApple())
     {
     // Versioning is supported only for shared libraries and modules,
diff --git a/Source/cmTarget.h b/Source/cmTarget.h
index d41c827..d70cacd 100644
--- a/Source/cmTarget.h
+++ b/Source/cmTarget.h
@@ -347,6 +347,9 @@ public:
   /** Get the name of the pdb file for the target.  */
   std::string GetPDBName(const char* config=0);
 
+  /** Whether this library has soname enabled and platform supports it.  */
+  bool HasSOName(const char* config);
+
   /** Get the soname of the target.  Allowed only for a shared library.  */
   std::string GetSOName(const char* config);