ENH: Improve linking to third-party shared libraries on soname platforms

  - Reduce false positives in cases of unknown soname
  - Make library extension regular expressions match only at end of string
  - When linking to libraries in implicit dirs convert to the -l option
    only if the file name is one that can be found by the linker
    (ex. /usr/lib/libfoo.so.1 should be linked by full path)
  - Add cmSystemTools::GuessLibrarySOName to guess the soname of a
    library based on presence of a symlink
  - In cmComputeLinkInformation try to guess an soname before assuming
    that a third-party library is built without an soname
  - In cmOrderDirectories guess the soname of shared libraries in cases
    it is otherwise unknown

1 files changed, 20 insertions, 5 deletions

diff --git a/Source/cmComputeLinkInformation.cxx b/Source/cmComputeLinkInformation.cxx
index 1da512c..1899bd2 100644
--- a/Source/cmComputeLinkInformation.cxx
+++ b/Source/cmComputeLinkInformation.cxx
@@ -27,6 +27,8 @@
 
 #include <ctype.h>
 
+//#define CM_COMPUTE_LINK_INFO_DEBUG
+
 /*
 Notes about linking on various platforms:
 
@@ -905,7 +907,7 @@ cmComputeLinkInformation
     }
 
   // Finish the list.
-  libext += ").*";
+  libext += ")$";
   return libext;
 }
 
@@ -1070,6 +1072,13 @@ bool cmComputeLinkInformation::CheckImplicitDirItem(std::string const& item)
     return false;
     }
 
+  // Only apply the policy below if the library file is one that can
+  // be found by the linker.
+  if(!this->ExtractAnyLibraryName.find(item))
+    {
+    return false;
+    }
+
   // Many system linkers support multiple architectures by
   // automatically selecting the implicit linker search path for the
   // current architecture.  If the library appears in an implicit link
@@ -1262,13 +1271,19 @@ bool cmComputeLinkInformation::CheckSharedLibNoSOName(std::string const& item)
 {
   // This platform will use the path to a library as its soname if the
   // library is given via path and was not built with an soname.  If
-  // this is a shared library that might be the case.  TODO: Check if
-  // the lib is a symlink to detect that it actually has an soname.
+  // this is a shared library that might be the case.
   std::string file = cmSystemTools::GetFilenameName(item);
   if(this->ExtractSharedLibraryName.find(file))
     {
-    this->AddSharedLibNoSOName(item);
-    return true;
+    // If we can guess the soname fairly reliably then assume the
+    // library has one.  Otherwise assume the library has no builtin
+    // soname.
+    std::string soname;
+    if(!cmSystemTools::GuessLibrarySOName(item, soname))
+      {
+      this->AddSharedLibNoSOName(item);
+      return true;
+      }
     }
   return false;
 }