c-decl.c (diagnose_mismatched_decls): Give error for external redeclaration of identifier declared with no linkage...

	* c-decl.c (diagnose_mismatched_decls): Give error for external
	redeclaration of identifier declared with no linkage, not just
	warning with -Wtraditional.  Do not check DECL_CONTEXT to give
	error for redeclaration with no linkage.

testsuite:
	* gcc.dg/redecl-2.c: New test.

From-SVN: r85386

4 files changed, 89 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 719578f..226591d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2004-07-31  Joseph S. Myers  <jsm@polyomino.org.uk>
+
+	* c-decl.c (diagnose_mismatched_decls): Give error for external
+	redeclaration of identifier declared with no linkage, not just
+	warning with -Wtraditional.  Do not check DECL_CONTEXT to give
+	error for redeclaration with no linkage.
+
 2004-07-30  Geoffrey Keating  <geoffk@apple.com>
 	    Fariborz Jahanian <fjahanian@apple.com>
 
diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index b14d331..27860b4 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -1325,7 +1325,14 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl,
 	{
 	  if (DECL_EXTERNAL (newdecl))
 	    {
-	      if (warn_traditional)
+	      if (!DECL_FILE_SCOPE_P (olddecl))
+		{
+		  error ("%Jextern declaration of %qD follows "
+			 "declaration with no linkage", newdecl, newdecl);
+		  locate_old_decl (olddecl, error);
+		  return false;
+		}
+	      else if (warn_traditional)
 		{
 		  warning ("%Jnon-static declaration of '%D' follows "
 			   "static declaration", newdecl, newdecl);
@@ -1347,13 +1354,10 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl,
 	}
       /* Two objects with the same name declared at the same block
 	 scope must both be external references (6.7p3).  */
-      else if (!DECL_FILE_SCOPE_P (newdecl)
-	       && DECL_CONTEXT (newdecl) == DECL_CONTEXT (olddecl)
-	       && (!DECL_EXTERNAL (newdecl) || !DECL_EXTERNAL (olddecl)))
+      else if (!DECL_FILE_SCOPE_P (newdecl))
 	{
 	  if (DECL_EXTERNAL (newdecl))
-	    error ("%Jextern declaration of '%D' follows "
-		   "declaration with no linkage", newdecl, newdecl);
+	    abort ();
 	  else if (DECL_EXTERNAL (olddecl))
 	    error ("%Jdeclaration of '%D' with no linkage follows "
 		   "extern declaration", newdecl, newdecl);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8bb22cd..28d487c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2004-07-31  Joseph S. Myers  <jsm@polyomino.org.uk>
+
+	* gcc.dg/redecl-2.c: New test.
+
 2004-07-30  Geoffrey Keating  <geoffk@apple.com>
 
 	* gcc.dg/darwin-longdouble.c: New file.
diff --git a/gcc/testsuite/gcc.dg/redecl-2.c b/gcc/testsuite/gcc.dg/redecl-2.c
new file mode 100644
index 0000000..b1b7dc9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/redecl-2.c
@@ -0,0 +1,68 @@
+/* Test for multiple declarations of an identifier at same block
+   scope: only valid case is all extern.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+void
+fa0 (void)
+{
+  int a0; /* { dg-error "previous declaration" } */
+  int a0; /* { dg-error "redeclaration" } */
+}
+
+void
+fa1 (void)
+{
+  int a1; /* { dg-error "previous declaration" } */
+  static int a1; /* { dg-error "redeclaration" } */
+}
+
+void
+fa2 (void)
+{
+  int a2; /* { dg-error "previous declaration" } */
+  extern int a2; /* { dg-error "follows declaration with no linkage" } */
+}
+
+void
+fa3 (void)
+{
+  static int a3; /* { dg-error "previous declaration" } */
+  int a3; /* { dg-error "redeclaration" } */
+}
+
+void
+fa4 (void)
+{
+  static int a4; /* { dg-error "previous declaration" } */
+  static int a4; /* { dg-error "redeclaration" } */
+}
+
+void
+fa5 (void)
+{
+  static int a5; /* { dg-error "previous declaration" } */
+  extern int a5; /* { dg-error "follows declaration with no linkage" } */
+}
+
+void
+fa6 (void)
+{
+  extern int a6; /* { dg-error "previous declaration" } */
+  int a6; /* { dg-error "follows extern declaration" } */
+}
+
+void
+fa7 (void)
+{
+  extern int a7; /* { dg-error "previous declaration" } */
+  static int a7; /* { dg-error "follows extern declaration" } */
+}
+
+void
+fa8 (void)
+{
+  extern int a8;
+  extern int a8;
+}