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Re: [Patch] Java: Definite [Un]Assignment Issues


On Thu, 27 May 2004 16:24:45 -0700, Per Bothner <per@bothner.com> wrote:
[...]
> It looks OK, but after looking the spec, I wonder whether
> following is also correct and simpler (more robust):
> 
>      case MODIFY_EXPR:
>        check_init (exp, before);
>        COPY (when_true, before);
>        COPY (when_false, before);
>        break;

Cool! The above simplifies the code for
check_bool_init() nicely - in fact, since the
default processing is also the same, I could just
remove the special treatment of MODIFY_EXPR
as shown in the patch appended below.

However, the total number of XPASSes and FAILs
still remain at 47 and 5 respectively after the
modified patch, as with my original patch.

Is the following OK for mainline then?

If yes, can I update jacks.xfail appropriately?

Thanks,
Ranjit.


Index: ChangeLog
from  Ranjit Mathew  <rmathew@hotmail.com>
	Per Bothner  <per@bothner.com>

	* java-tree.h (DECL_LOCAL_FINAL_IUD): New macro to test if a
	local variable was initialised upon declaration.
	* parse.y (declare_local_variables): Set DECL_LOCAL_FINAL_IUD if
	variable was final and initialised upon declaration.
	* check-init.c (check_final_reassigned): Give error only if a blank
	final is not definitely unassigned or if an initialised final is
	reassigned.
	(check_bool_init): Respect JLS2 16.1.7 requirements for boolean
	assignment expressions. Remove case MODIFY_EXPR, label do_default.
	(check_init): Perform initialised-variable-removing-optimisation
	only on non-final local variables.

Index: java-tree.h
===================================================================
--- java-tree.h	2004-05-23 17:33:35.000000000 +0530
+++ java-tree.h	2004-05-23 17:36:45.000000000 +0530
@@ -902,8 +902,8 @@ union lang_tree_node 
 /* Safely tests whether FIELD_INNER_ACCESS exists or not. */
 #define FIELD_INNER_ACCESS_P(DECL) \
   DECL_LANG_SPECIFIC (DECL) && FIELD_INNER_ACCESS (DECL)
-/* True if a final variable was initialized upon its declaration,
-   or (if a field) in an initializer.  Set after definite assignment. */
+/* True if a final field was initialized upon its declaration
+   or in an initializer.  Set after definite assignment.  */
 #define DECL_FIELD_FINAL_IUD(NODE)  (DECL_LANG_SPECIFIC (NODE)->u.v.final_iud)
 /* The original WFL of a final variable. */
 #define DECL_FIELD_FINAL_WFL(NODE)  (DECL_LANG_SPECIFIC(NODE)->u.v.wfl)
@@ -911,6 +911,8 @@ union lang_tree_node 
 #define DECL_OWNER(NODE)            (DECL_LANG_SPECIFIC(NODE)->u.v.owner)
 /* True if NODE is a local variable final. */
 #define LOCAL_FINAL_P(NODE) (DECL_LANG_SPECIFIC (NODE) && DECL_FINAL (NODE))
+/* True if a final local variable was initialized upon its declaration.  */
+#define DECL_LOCAL_FINAL_IUD(NODE)  (DECL_LANG_SPECIFIC (NODE)->u.v.final_iud)
 /* True if NODE is a final field. */
 #define FINAL_VARIABLE_P(NODE) (FIELD_FINAL (NODE) && !FIELD_STATIC (NODE))
 /* True if NODE is a class final field. */
Index: parse.y
===================================================================
--- parse.y	2004-05-23 15:59:32.000000000 +0530
+++ parse.y	2004-05-23 17:37:35.000000000 +0530
@@ -7375,6 +7375,13 @@ declare_local_variables (int modifier, t
       if (init && java_error_count)
 	init = NULL_TREE;
 
+      /* Remember it if this is an initialized-upon-declaration final
+         variable.  */
+      if (init && final_p)
+        {
+          DECL_LOCAL_FINAL_IUD (decl) = 1;
+        }
+
       /* Add the initialization function to the current function's code */
       if (init)
 	{
Index: check-init.c
===================================================================
--- check-init.c	2004-05-21 21:14:10.000000000 +0530
+++ check-init.c	2004-05-28 23:14:19.000000000 +0530
@@ -210,7 +210,8 @@ check_final_reassigned (tree decl, words
      assigned must be reported as errors */
   if (DECL_FINAL (decl) && index != -2
       && (index < loop_current_locals /* I.e. -1, or outside current loop. */
-	  || ! UNASSIGNED_P (before, index)))
+	  || (! DECL_LOCAL_FINAL_IUD (decl) && ! UNASSIGNED_P (before, index))
+	  || (DECL_LOCAL_FINAL_IUD (decl) && ASSIGNED_P (before, index))))
     {
       final_assign_error (DECL_NAME (decl));
     }
@@ -337,27 +338,6 @@ check_bool_init (tree exp, words before,
     case TRUTH_NOT_EXPR:
       check_bool_init (TREE_OPERAND (exp, 0), before, when_true, when_false);
       return;
-    case MODIFY_EXPR:
-      {
-	tree tmp = TREE_OPERAND (exp, 0);
-	if ((tmp = get_variable_decl (tmp)) != NULL_TREE)
-	  {
-	    int index;
-	    check_bool_init (TREE_OPERAND (exp, 1), before,
-			     when_false, when_true);
-	    check_final_reassigned (tmp, before);
-	    index = DECL_BIT_INDEX (tmp);
-	    if (index >= 0)
-	      {
-		SET_ASSIGNED (when_false, index);
-		SET_ASSIGNED (when_true, index);
-		CLEAR_UNASSIGNED (when_false, index);
-		CLEAR_UNASSIGNED (when_true, index);
-	      }
-	    break;
-	  }
-      }
-      goto do_default;
 
     case BIT_AND_EXPR:
     case BIT_IOR_EXPR:
@@ -390,8 +370,8 @@ check_bool_init (tree exp, words before,
 	  COPY (when_true, before);
 	}
       break;
+
     default:
-    do_default:
       check_init (exp, before);
       COPY (when_false, before);
       COPY (when_true, before);
@@ -531,6 +511,7 @@ check_init (tree exp, words before)
 	     definitely assigned when once we checked the whole
 	     function. */
 	  if (! STATIC_CLASS_INIT_OPT_P () /* FIXME */
+	      && ! DECL_FINAL (tmp)
 	      && index >= start_current_locals
 	      && index == num_current_locals - 1)
 	    {


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