c-common.c (shadow_warning): New function, moved from cp/decl.c.

	* c-common.c (shadow_warning): New function, moved from cp/decl.c.
	* c-common.h (shadow_warning): New.
	* c-decl.c: Include c-common.h.
	(warn_if_shadowing): New, broken out of pushdecl.
	(pushdecl): Use warn_if_shadowing.
	(store_parm_decls): Prevent duplicate -Wshadow warnings.
cp:
	* decl.c: Include c-common.h.
	(shadow_warning): Move to c-common.c.
testsuite:
	* gcc.dg/Wshadow-1.c: New test.

From-SVN: r47701

1 files changed, 72 insertions, 45 deletions

diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 5471f6b..fb1d8e8 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -45,6 +45,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "target.h"
 #include "debug.h"
 #include "timevar.h"
+#include "c-common.h"
 
 /* In grokdeclarator, distinguish syntactic contexts of declarators.  */
 enum decl_context
@@ -280,6 +281,7 @@ static tree grokparms			PARAMS ((tree, int));
 static void layout_array_type		PARAMS ((tree));
 static tree c_make_fname_decl           PARAMS ((tree, int));
 static void c_expand_body               PARAMS ((tree, int, int));
+static void warn_if_shadowing		PARAMS ((tree, tree));
 
 /* C-specific option variables.  */
 
@@ -2047,6 +2049,66 @@ duplicate_decls (newdecl, olddecl, different_binding_level)
   return 1;
 }
 
+/* Check whether decl-node X shadows an existing declaration.
+   OLDLOCAL is the old IDENTIFIER_LOCAL_VALUE of the DECL_NAME of X,
+   which might be a NULL_TREE.  */
+static void
+warn_if_shadowing (x, oldlocal)
+     tree x, oldlocal;
+{
+  tree name;
+
+  if (DECL_EXTERNAL (x))
+    return;
+
+  name = DECL_NAME (x);
+
+  /* Warn if shadowing an argument at the top level of the body.  */
+  if (oldlocal != 0
+      /* This warning doesn't apply to the parms of a nested fcn.  */
+      && ! current_binding_level->parm_flag
+      /* Check that this is one level down from the parms.  */
+      && current_binding_level->level_chain->parm_flag
+      /* Check that the decl being shadowed
+	 comes from the parm level, one level up.  */
+      && chain_member (oldlocal, current_binding_level->level_chain->names))
+    {
+      if (TREE_CODE (oldlocal) == PARM_DECL)
+	pedwarn ("declaration of `%s' shadows a parameter",
+		 IDENTIFIER_POINTER (name));
+      else
+	pedwarn ("declaration of `%s' shadows a symbol from the parameter list",
+		 IDENTIFIER_POINTER (name));
+    }
+  /* Maybe warn if shadowing something else.  */
+  else if (warn_shadow
+	   /* No shadow warnings for internally generated vars.  */
+	   && DECL_SOURCE_LINE (x) != 0
+	   /* No shadow warnings for vars made for inlining.  */
+	   && ! DECL_FROM_INLINE (x))
+    {
+      if (TREE_CODE (x) == PARM_DECL
+	  && current_binding_level->level_chain->parm_flag)
+	/* Don't warn about the parm names in function declarator
+	   within a function declarator.
+	   It would be nice to avoid warning in any function
+	   declarator in a declaration, as opposed to a definition,
+	   but there is no way to tell it's not a definition.  */
+	;
+      else if (oldlocal)
+	{
+	  if (TREE_CODE (oldlocal) == PARM_DECL)
+	    shadow_warning ("a parameter", name, oldlocal);
+	  else
+	    shadow_warning ("a previous local", name, oldlocal);
+	}
+      else if (IDENTIFIER_GLOBAL_VALUE (name) != 0
+	       && IDENTIFIER_GLOBAL_VALUE (name) != error_mark_node)
+	shadow_warning ("a global declaration", name,
+			IDENTIFIER_GLOBAL_VALUE (name));
+    }
+}
+
 /* Record a decl-node X as belonging to the current lexical scope.
    Check for errors (such as an incompatible declaration for the same
    name already seen in the same scope).
@@ -2431,49 +2493,7 @@ pushdecl (x)
 		IDENTIFIER_LIMBO_VALUE (name) = x;
 	    }
 
-	  /* Warn if shadowing an argument at the top level of the body.  */
-	  if (oldlocal != 0 && !DECL_EXTERNAL (x)
-	      /* This warning doesn't apply to the parms of a nested fcn.  */
-	      && ! current_binding_level->parm_flag
-	      /* Check that this is one level down from the parms.  */
-	      && current_binding_level->level_chain->parm_flag
-	      /* Check that the decl being shadowed
-		 comes from the parm level, one level up.  */
-	      && chain_member (oldlocal, current_binding_level->level_chain->names))
-	    {
-	      if (TREE_CODE (oldlocal) == PARM_DECL)
-		pedwarn ("declaration of `%s' shadows a parameter",
-			 IDENTIFIER_POINTER (name));
-	      else
-		pedwarn ("declaration of `%s' shadows a symbol from the parameter list",
-			 IDENTIFIER_POINTER (name));
-	    }
-
-	  /* Maybe warn if shadowing something else.  */
-	  else if (warn_shadow && !DECL_EXTERNAL (x)
-		   /* No shadow warnings for internally generated vars.  */
-		   && DECL_SOURCE_LINE (x) != 0
-		   /* No shadow warnings for vars made for inlining.  */
-		   && ! DECL_FROM_INLINE (x))
-	    {
-	      const char *id = IDENTIFIER_POINTER (name);
-
-	      if (TREE_CODE (x) == PARM_DECL
-		  && current_binding_level->level_chain->parm_flag)
-		/* Don't warn about the parm names in function declarator
-		   within a function declarator.
-		   It would be nice to avoid warning in any function
-		   declarator in a declaration, as opposed to a definition,
-		   but there is no way to tell it's not a definition.  */
-		;
-	      else if (oldlocal != 0 && TREE_CODE (oldlocal) == PARM_DECL)
-		warning ("declaration of `%s' shadows a parameter", id);
-	      else if (oldlocal != 0)
-		warning ("declaration of `%s' shadows previous local", id);
-	      else if (IDENTIFIER_GLOBAL_VALUE (name) != 0
-		       && IDENTIFIER_GLOBAL_VALUE (name) != error_mark_node)
-		warning ("declaration of `%s' shadows global declaration", id);
-	    }
+	  warn_if_shadowing (x, oldlocal);
 
 	  /* If storing a local value, there may already be one (inherited).
 	     If so, record it for restoration when this binding level ends.  */
@@ -6354,11 +6374,16 @@ store_parm_decls ()
      then CONST_DECLs for foo and bar are put here.  */
   tree nonparms = 0;
 
+  /* The function containing FNDECL, if any.  */
+  tree context = decl_function_context (fndecl);
+
   /* Nonzero if this definition is written with a prototype.  */
   int prototype = 0;
 
-  /* The function containing FNDECL, if any.  */
-  tree context = decl_function_context (fndecl);
+  int saved_warn_shadow = warn_shadow;
+
+  /* Don't re-emit shadow warnings.  */
+  warn_shadow = 0;
 
   if (specparms != 0 && TREE_CODE (specparms) != TREE_LIST)
     {
@@ -6758,6 +6783,8 @@ store_parm_decls ()
      not safe to try to expand expressions involving them.  */
   immediate_size_expand = 0;
   cfun->x_dont_save_pending_sizes_p = 1;
+
+  warn_shadow = saved_warn_shadow;
 }
 
 /* Finish up a function declaration and compile that function