Re: Remove warning about unreachable bytecodes

[Tom Tromey <tromey at redhat dot com>]

Bryce> I vote to remove it, or perhaps we can make it only appear with -Wall.

Andrew> I agree.  It seems that these compilers will not cease to produce
Andrew> unreachable bytecode.

Per> Having it be controlled by -Wall or perhaps -Wextra seems a godd idea.

Sounds like consensus.

Here's my old patch as a starting point.
Do we want a new option?
Do we want if off by default?

Tom

Index: gcc/java/ChangeLog
from  Tom Tromey  <tromey@redhat.com>

	* gcj.texi (Warnings): Document -Wunreachable-bytecode.
	* expr.c (expand_byte_code): Use flag_unreachable_bytecode.
	* java-tree.h (flag_unreachable_bytecode): Declare.
	* lang.c (lang_W_options) [unreachable-bytecode]: Added.
	(flag_unreachable_bytecode): New global.
	(java_decode_option): Set flag_unreachable_bytecode with -Wall.

Index: gcc/java/expr.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/java/expr.c,v
retrieving revision 1.147
diff -u -r1.147 expr.c
--- gcc/java/expr.c 4 Jun 2002 20:31:54 -0000 1.147
+++ gcc/java/expr.c 17 Jun 2002 03:57:36 -0000
@@ -1,5 +1,5 @@
 /* Process expressions for the GNU compiler for the Java(TM) language.
-   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001
+   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002
    Free Software Foundation, Inc.
 
 This file is part of GNU CC.
@@ -2852,8 +2852,9 @@
 	  if (dead_code_index != -1)
 	    {
               /* We've just reached the end of a region of dead code.  */
-              warning ("unreachable bytecode from %d to before %d",
-                       dead_code_index, PC);
+	      if (flag_unreachable_bytecode)
+		warning ("unreachable bytecode from %d to before %d",
+			 dead_code_index, PC);
               dead_code_index = -1;
             }
 	}
@@ -2889,8 +2890,9 @@
   if (dead_code_index != -1)
     {
       /* We've just reached the end of a region of dead code.  */
-      warning ("unreachable bytecode from %d to the end of the method", 
-              dead_code_index);
+      if (flag_unreachable_bytecode)
+	warning ("unreachable bytecode from %d to the end of the method", 
+		 dead_code_index);
     }
 }
 
Index: gcc/java/gcj.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/java/gcj.texi,v
retrieving revision 1.31
diff -u -r1.31 gcj.texi
--- gcc/java/gcj.texi 4 Jun 2002 22:00:42 -0000 1.31
+++ gcc/java/gcj.texi 17 Jun 2002 03:57:38 -0000
@@ -351,12 +351,16 @@
 newer than its matching class file.  By default @command{gcj} will warn
 about this.
 
+@item -Wunreachable-bytecode
+This warns about unreachable bytecode in the compiled @file{.class}
+files.  This warning is enabled by default.
+
 @item -Wunused
 This is the same as @command{gcc}'s @code{-Wunused}.
 
 @item -Wall
 This is the same as @code{-Wredundant-modifiers -Wextraneous-semicolon
--Wunused}.
+-Wunused -Wunreachable-bytecode}.
 @end table
 
 
Index: gcc/java/java-tree.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/java/java-tree.h,v
retrieving revision 1.153
diff -u -r1.153 java-tree.h
--- gcc/java/java-tree.h 11 Jun 2002 17:31:10 -0000 1.153
+++ gcc/java/java-tree.h 17 Jun 2002 03:57:40 -0000
@@ -169,6 +169,10 @@
 
 extern int flag_extraneous_semicolon;
 
+/* When non zero, report unreachable bytecode.  */
+
+extern int flag_unreachable_bytecode;
+
 /* When non zero, always check for a non gcj generated classes archive.  */
 
 extern int flag_force_classes_archive_check;
Index: gcc/java/lang.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/java/lang.c,v
retrieving revision 1.103
diff -u -r1.103 lang.c
--- gcc/java/lang.c 10 Jun 2002 05:11:42 -0000 1.103
+++ gcc/java/lang.c 17 Jun 2002 03:57:40 -0000
@@ -1,5 +1,5 @@
 /* Java(TM) language-specific utility routines.
-   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001
+   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002
    Free Software Foundation, Inc.
 
 This file is part of GNU CC.
@@ -155,6 +155,9 @@
 /* When non zero, report the now deprecated empty statements.  */
 int flag_extraneous_semicolon;
 
+/* When non zero, report unreachable bytecode.  */
+int flag_unreachable_bytecode = 1;
+
 /* When non zero, always check for a non gcj generated classes archive.  */
 int flag_force_classes_archive_check;
 
@@ -204,7 +207,8 @@
 {
   { "redundant-modifiers", &flag_redundant, 1 },
   { "extraneous-semicolon", &flag_extraneous_semicolon, 1 },
-  { "out-of-date", &flag_newer, 1 }
+  { "out-of-date", &flag_newer, 1 },
+  { "unreachable-bytecode", &flag_unreachable_bytecode, 1 }
 };
 
 JCF *current_jcf;
@@ -422,6 +426,7 @@
       flag_wall = 1;
       flag_redundant = 1;
       flag_extraneous_semicolon = 1;
+      flag_unreachable_bytecode = 1;
       /* When -Wall given, enable -Wunused.  We do this because the C
 	 compiler does it, and people expect it.  */
       set_Wunused (1);
Index: libjava/testsuite/ChangeLog
from  Tom Tromey  <tromey@redhat.com>

	* lib/libjava.exp (find_javac): Use -Wno-unreachable-bytecode.

Index: libjava/testsuite/lib/libjava.exp
===================================================================
RCS file: /cvs/gcc/gcc/libjava/testsuite/lib/libjava.exp,v
retrieving revision 1.42
diff -u -r1.42 libjava.exp
--- libjava/testsuite/lib/libjava.exp 13 Jun 2002 17:34:47 -0000 1.42
+++ libjava/testsuite/lib/libjava.exp 17 Jun 2002 03:57:42 -0000
@@ -71,7 +71,10 @@
 	if {[info exists env(SUN_JAVAC)]} {
 	    set SUN_JAVAC $env(SUN_JAVAC)
 	} else {
-	    set SUN_JAVAC "$GCJ_UNDER_TEST -C"
+	    # Use -Wno-unreachable-bytecode because we don't currently
+	    # care about such warnings, and they cause dejagnu to
+	    # think we've hit an error.
+	    set SUN_JAVAC "$GCJ_UNDER_TEST -C -Wno-unreachable-bytecode"
 	}
     }
     return $SUN_JAVAC