re PR c++/19159 (Undefined symbol: vtable for __cxxabiv1::__vmi_class_type_info)

	PR c++/19159
	* decl2.c (import_export_decl): Use non-COMDAT external linkage
	for virtual tables, typeinfo, etc. that will be emitted in only
	one translation unit on systems without weak symbols.

From-SVN: r97635

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index ac3c3bcdb99c76fa7288f942fd049654db20035c..a2747146878a150d689e12ee796a0916f7a3112e 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2005-04-05  Mark Mitchell  <mark@codesourcery.com>
+
+       PR c++/19159
+       * decl2.c (import_export_decl): Use non-COMDAT external linkage
+       for virtual tables, typeinfo, etc. that will be emitted in only
+       one translation unit on systems without weak symbols.
+
 2005-04-04  Mark Mitchell  <mark@codesourcery.com>
 
        PR c++/20679

diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 16c4efe76a2c70bf64db41b3b85ed251d87843ea..4a2659b3f215ae9a2fee83f83e400032f813db76 100644 (file)
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1780,29 +1780,43 @@ import_export_decl (tree decl)
       else if (CLASSTYPE_INTERFACE_KNOWN (type)
               && CLASSTYPE_INTERFACE_ONLY (type))
        import_p = true;
-      else if (TARGET_WEAK_NOT_IN_ARCHIVE_TOC
+      else if ((!flag_weak || TARGET_WEAK_NOT_IN_ARCHIVE_TOC)
               && !CLASSTYPE_USE_TEMPLATE (type)
               && CLASSTYPE_KEY_METHOD (type)
               && !DECL_DECLARED_INLINE_P (CLASSTYPE_KEY_METHOD (type)))
        /* The ABI requires that all virtual tables be emitted with
           COMDAT linkage.  However, on systems where COMDAT symbols
           don't show up in the table of contents for a static
-          archive, the linker will report errors about undefined
-          symbols because it will not see the virtual table
-          definition.  Therefore, in the case that we know that the
-          virtual table will be emitted in only one translation
-          unit, we make the virtual table an ordinary definition
-          with external linkage.  */
+          archive, or on systems without weak symbols (where we
+          approximate COMDAT linkage by using internal linkage), the
+          linker will report errors about undefined symbols because
+          it will not see the virtual table definition.  Therefore,
+          in the case that we know that the virtual table will be
+          emitted in only one translation unit, we make the virtual
+          table an ordinary definition with external linkage.  */
        DECL_EXTERNAL (decl) = 0;
       else if (CLASSTYPE_INTERFACE_KNOWN (type))
        {
          /* TYPE is being exported from this translation unit, so DECL
-            should be defined here.  The ABI requires COMDAT
-            linkage.  Normally, we only emit COMDAT things when they
-            are needed; make sure that we realize that this entity is
-            indeed needed.  */
-         comdat_p = true;
-         mark_needed (decl);
+            should be defined here.  */ 
+         if (!flag_weak && CLASSTYPE_EXPLICIT_INSTANTIATION (type))
+           /* If a class is declared in a header with the "extern
+              template" extension, then it will not be instantiated,
+              even in translation units that would normally require
+              it.  Often such classes are explicitly instantiated in
+              one translation unit.  Therefore, the explicit
+              instantiation must be made visible to other translation
+              units.  */
+           DECL_EXTERNAL (decl) = 0;
+         else
+           {
+             /* The ABI requires COMDAT linkage.  Normally, we only
+                emit COMDAT things when they are needed; make sure
+                that we realize that this entity is indeed
+                needed.  */
+             comdat_p = true;
+             mark_needed (decl);
+           }
        }
       else if (!flag_implicit_templates
               && CLASSTYPE_IMPLICIT_INSTANTIATION (type))
@@ -1830,7 +1844,14 @@ import_export_decl (tree decl)
              comdat_p = true;
              if (CLASSTYPE_INTERFACE_KNOWN (type)
                  && !CLASSTYPE_INTERFACE_ONLY (type))
-               mark_needed (decl);
+               {
+                 mark_needed (decl);
+                 if (!flag_weak)
+                   {
+                     comdat_p = false;
+                     DECL_EXTERNAL (decl) = 0;
+                   }
+               }
            }
        }
       else