re PR middle-end/9936 (ICE with local function and variable-length 2d array)

	PR c/9936
	* c-decl.c (grokdeclarator): Clear SAVE_EXPR_CONTEXT for
	variably-sized arrays in parameters.
	(set_save_expr_context): New function.
	(c_expand_body): Use it, via walk_tree.

	PR c/9936
	* gcc.dg/20030331-2.c: New test.

From-SVN: r65128

1 files changed, 42 insertions, 1 deletions

diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index c9dd711..e0354f0f 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -4103,7 +4103,20 @@ grokdeclarator (declarator, declspecs, decl_context, initialized)
 		    }
 
 		  if (size_varies)
-		    itype = variable_size (itype);
+		    {
+		      /* We must be able to distinguish the
+			 SAVE_EXPR_CONTEXT for the variably-sized type
+			 so that we can set it correctly in
+			 set_save_expr_context.  The convention is
+			 that all SAVE_EXPRs that need to be reset
+			 have NULL_TREE for their SAVE_EXPR_CONTEXT.  */
+		      tree cfd = current_function_decl;
+		      if (decl_context == PARM)
+			current_function_decl = NULL_TREE;
+		      itype = variable_size (itype);
+		      if (decl_context == PARM)
+			current_function_decl = cfd;
+		    }
 		  itype = build_index_type (itype);
 		}
 	    }
@@ -6508,6 +6521,25 @@ c_expand_deferred_function (fndecl)
     }
 }
 
+/* Called to move the SAVE_EXPRs for parameter declarations in a
+   nested function into the nested function.  DATA is really the
+   nested FUNCTION_DECL.  */
+
+static tree
+set_save_expr_context (tree *tp, 
+		       int *walk_subtrees,
+		       void *data)
+{
+  if (TREE_CODE (*tp) == SAVE_EXPR && !SAVE_EXPR_CONTEXT (*tp))
+    SAVE_EXPR_CONTEXT (*tp) = (tree) data;
+  /* Do not walk back into the SAVE_EXPR_CONTEXT; that will cause
+     circularity.  */
+  else if (DECL_P (*tp))
+    *walk_subtrees = 0;
+
+  return NULL_TREE;
+}
+
 /* Generate the RTL for the body of FNDECL.  If NESTED_P is nonzero,
    then we are already in the process of generating RTL for another
    function.  If can_defer_p is zero, we won't attempt to defer the
@@ -6548,6 +6580,15 @@ c_expand_body_1 (fndecl, nested_p)
   /* Set up parameters and prepare for return, for the function.  */
   expand_function_start (fndecl, 0);
 
+  /* If the function has a variably modified type, there may be
+     SAVE_EXPRs in the parameter types.  Their context must be set to
+     refer to this function; they cannot be expanded in the containing
+     function.  */
+  if (decl_function_context (fndecl)
+      && variably_modified_type_p (TREE_TYPE (fndecl)))
+    walk_tree (&TREE_TYPE (fndecl), set_save_expr_context, fndecl,
+	       NULL);
+	     
   /* If this function is `main', emit a call to `__main'
      to run global initializers, etc.  */
   if (DECL_NAME (fndecl)