re PR c++/31923 (g++ accepts a storage-class-specifier on a template explicit specialization)

gcc/cp/ChangeLog
2007-06-15  Simon Baldwin <simonb@google.com>

        PR c++/31923
        * parser.c (cp_parser_single_declaration): Added check for storage
        class other than sc_none in parsed declaration, and a flag to indicate
        if the call is part of an explicit template specialization parse.
        * (cp_parser_explicit_specialization): Specialization check flag added
        to call to cp_parser_single_declaration(), set true.
        * (cp_parser_template_declaration_after_export): Specialization check
        flag added to call to cp_parser_single_declaration(), set false.
        * pt.c (check_explicit_specialization): Added code to copy visiblity
        and linkage from the templated function to the explicit specialization.
  
gcc/testsuite/ChangeLog
2007-06-15  Simon Baldwin <simonb@google.com>
  
        PR c++/31923
        * g++.dg/template/error25.C: New.
        * g++.dg/template/spec35.C: New.

From-SVN: r125829

gcc/cp/ChangeLog

@@ -1,3 +1,16 @@
+2007-06-18  Simon Baldwin <simonb@google.com>
+
+	PR c++/31923
+	* parser.c (cp_parser_single_declaration): Added check for storage
+	class other than sc_none in parsed declaration, and a flag to indicate
+	if the call is part of an explicit template specialization parse.
+	* (cp_parser_explicit_specialization): Specialization check flag added
+	to call to cp_parser_single_declaration(), set true.
+	* (cp_parser_template_declaration_after_export): Specialization check
+	flag added to call to cp_parser_single_declaration(), set false.
+	* pt.c (check_explicit_specialization): Added code to copy visiblity
+	and linkage from the templated function to the explicit specialization.
+
 2007-06-15  Andrew Pinski  <andrew_pinski@playstation.sony.com>
 
 	* typeck.c (build_binary_op): For templates build the

gcc/cp/parser.c

@@ -1913,7 +1913,7 @@ static void cp_parser_template_declaration_after_export
 static void cp_parser_perform_template_parameter_access_checks
   (VEC (deferred_access_check,gc)*);
 static tree cp_parser_single_declaration
-  (cp_parser *, VEC (deferred_access_check,gc)*, bool, bool *);
+  (cp_parser *, VEC (deferred_access_check,gc)*, bool, bool, bool *);
 static tree cp_parser_functional_cast
   (cp_parser *, tree);
 static tree cp_parser_save_member_function_body
@@ -10225,6 +10225,7 @@ cp_parser_explicit_specialization (cp_parser* parser)
     cp_parser_single_declaration (parser,
 				  /*checks=*/NULL,
 				  /*member_p=*/false,
+                                  /*explicit_specialization_p=*/true,
 				  /*friend_p=*/NULL);
   /* We're done with the specialization.  */
   end_specialization ();
@@ -16510,6 +16511,7 @@ cp_parser_template_declaration_after_export (cp_parser* parser, bool member_p)
       decl = cp_parser_single_declaration (parser,
 					   checks,
 					   member_p,
+                                           /*explicit_specialization_p=*/false,
 					   &friend_p);
       pop_deferring_access_checks ();
 
@@ -16575,6 +16577,7 @@ static tree
 cp_parser_single_declaration (cp_parser* parser,
 			      VEC (deferred_access_check,gc)* checks,
 			      bool member_p,
+                              bool explicit_specialization_p,
 			      bool* friend_p)
 {
   int declares_class_or_enum;
@@ -16648,6 +16651,7 @@ cp_parser_single_declaration (cp_parser* parser,
   if (!decl
       && (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON)
 	  || decl_specifiers.type != error_mark_node))
+    {
       decl = cp_parser_init_declarator (parser,
 				        &decl_specifiers,
 				        checks,
@@ -16656,6 +16660,19 @@ cp_parser_single_declaration (cp_parser* parser,
 				        declares_class_or_enum,
 				        &function_definition_p);
 
+    /* 7.1.1-1 [dcl.stc]
+
+       A storage-class-specifier shall not be specified in an explicit
+       specialization...  */
+    if (decl
+        && explicit_specialization_p
+        && decl_specifiers.storage_class != sc_none)
+      {
+        error ("explicit template specialization cannot have a storage class");
+        decl = error_mark_node;
+      }
+    }
+
   pop_deferring_access_checks ();
 
   /* Clear any current qualification; whatever comes next is the start

gcc/cp/pt.c

@@ -2193,6 +2193,37 @@ check_explicit_specialization (tree declarator,
 	  TREE_PRIVATE (decl) = TREE_PRIVATE (gen_tmpl);
 	  TREE_PROTECTED (decl) = TREE_PROTECTED (gen_tmpl);
 
+          /* 7.1.1-1 [dcl.stc]
+
+             A storage-class-specifier shall not be specified in an
+             explicit specialization...
+
+             The parser rejects these, so unless action is taken here,
+             explicit function specializations will always appear with
+             global linkage.
+
+             The action recommended by the C++ CWG in response to C++
+             defect report 605 is to make the storage class and linkage
+             of the explicit specialization match the templated function:
+
+             http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
+           */
+          if (tsk == tsk_expl_spec && DECL_FUNCTION_TEMPLATE_P (gen_tmpl))
+            {
+              tree tmpl_func = DECL_TEMPLATE_RESULT (gen_tmpl);
+              gcc_assert (TREE_CODE (tmpl_func) == FUNCTION_DECL);
+
+              /* This specialization has the same linkage and visiblity as
+                 the function template it specializes.  */
+              TREE_PUBLIC (decl) = TREE_PUBLIC (tmpl_func);
+              DECL_THIS_STATIC (decl) = DECL_THIS_STATIC (tmpl_func);
+              if (DECL_VISIBILITY_SPECIFIED (tmpl_func))
+                {
+                  DECL_VISIBILITY_SPECIFIED (decl) = 1;
+                  DECL_VISIBILITY (decl) = DECL_VISIBILITY (tmpl_func);
+                }
+            }
+
 	  /* If DECL is a friend declaration, declared using an
 	     unqualified name, the namespace associated with DECL may
 	     have been set incorrectly.  For example, in:

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2007-06-18  Simon Baldwin <simonb@google.com>
+
+	PR c++/31923
+	* g++.dg/template/error25.C: New.
+	* g++.dg/template/spec35.C: New.
+
 2007-06-18  Kenneth Zadeck <zadeck@naturalbridge.com>
 
 	* gcc.c-torture/compile/pr32355.c: New testcase.

gcc/testsuite/g++.dg/template/error25.C

@@ -0,0 +1,16 @@
+// PR c++/31923
+
+template<class T>
+static void f1 ();
+
+template<>
+static void f1<void> ();  // { dg-error "explicit template specialization cannot have a storage class" }
+
+template<class T>
+extern void f2 ();
+
+template<>
+extern void f2<void> ();  // { dg-error "explicit template specialization cannot have a storage class" }
+
+export template<class T>  // { dg-warning "keyword 'export' not implemented" }
+static void* f3 ();

gcc/testsuite/g++.dg/template/spec35.C

@@ -0,0 +1,29 @@
+// PR c++/31923
+// C++ DR 605 -- "...the linkage of an explicit specialization must be that of
+// the template."
+
+// { dg-require-weak "" }
+// { dg-do compile { target i?86-*-* x86_64-*-* } }
+
+template<class T>
+static void f1 (T) { }
+
+// { dg-final { scan-assembler-not ".glob(a|)l\[\t \]*_Z2f1IfEvT_" } }
+template<>
+void f1<float> (float) { }  // Expected to have static linkage
+
+template<class T>
+void f2 (T) { }
+
+// { dg-final { scan-assembler ".glob(a|)l\[\t \]*_Z2f2IfEvT_" } }
+template<>
+void f2<float> (float) { }  // Expected to have global linkage
+
+void instantiator ()
+{
+  // { dg-final { scan-assembler-not ".glob(a|)l\[\t \]*_Z2f1IiEvT_" } }
+  f1(0);  // Expected to have static linkage
+
+  // { dg-final { scan-assembler ".weak\[\t \]*_Z2f2IiEvT_" } }
+  f2(0);  // Expected to have weak global linkage
+}