patch: better errors messages from java verifier

[Per Bothner]

Yesterday I found where Kawa was generating incorrect bytecode,
causing the Java run-time verifier to complain.  I noticed that
the Sun verifier gave a more informative error message (though
without the all-important bytecode pc), and decided to improve
gcj's verifier's error reporting once more.

I'm checking this in, even though one could argue it is a feature
rather than a bug-fix, and so should wait until after the branch.
But since bad .class files don't come around that often, it would
be too easy to just lose the patch.  (Also, this way I'm less
likely to leave out an important patch!)

2001-01-21  Per Bothner  <per@bothner.com>

	* verify.c (VERIFICATION_ERROR_WITH_INDEX):  New macro.
	(verify_jvm_instructions):  Use it, for better error messages on loads.

Index: verify.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/java/verify.c,v
retrieving revision 1.36
diff -u -p -r1.36 verify.c
--- verify.c	2001/01/21 20:26:37	1.36
+++ verify.c	2001/01/21 20:28:58
@@ -348,6 +348,9 @@ start_pc_cmp (xp, yp)
 #define VERIFICATION_ERROR(MESSAGE) \
   do { message = MESSAGE;  goto verify_error; } while (0)
 
+#define VERIFICATION_ERROR_WITH_INDEX(MESSAGE) \
+  do { message = MESSAGE;  goto error_with_index; } while (0)
+
 /* Recursive helper function to pop argument types during verifiation.
    ARG_TYPES is the list of formal parameter types.
    Return NULL on success and a freshly malloc'd error message on failure. */
@@ -412,6 +415,7 @@ verify_jvm_instructions (jcf, byte_ops, 
   const char *message;
   char *pmessage;
   int i;
+  int index;
   register unsigned char *p;
   struct eh_range *prev_eh_ranges = NULL_EH_RANGE;
   struct eh_range *eh_ranges;
@@ -476,7 +480,6 @@ verify_jvm_instructions (jcf, byte_ops, 
 
   for (PC = 0;;)
     {
-      int index;
       tree type, tmp;
       if (((PC != INVALID_PC
 	   && instruction_bits [PC] & BCODE_TARGET) != 0)
@@ -640,9 +643,13 @@ verify_jvm_instructions (jcf, byte_ops, 
 	if (index < 0
 	    || (index + TYPE_IS_WIDE (type)
 		>= DECL_MAX_LOCALS (current_function_decl)))
-	  VERIFICATION_ERROR ("invalid local variable index in load");
+	  VERIFICATION_ERROR_WITH_INDEX
+	    ("invalid local variable index %d in load");
 	tmp = type_map[index];
-	if (tmp == TYPE_UNKNOWN || tmp == TYPE_SECOND
+	if (tmp == TYPE_UNKNOWN)
+	  VERIFICATION_ERROR_WITH_INDEX
+	    ("loading local variable %d which has unknown type");
+	else if (tmp == TYPE_SECOND
 	    || (TYPE_IS_WIDE (type)
 		&& type_map[index+1] != void_type_node)
 	    || (type == ptr_type_node
@@ -650,7 +657,8 @@ verify_jvm_instructions (jcf, byte_ops, 
 		: type == int_type_node
 		? (! INTEGRAL_TYPE_P (tmp) || TYPE_PRECISION (tmp) > 32)
 		: type != tmp))
-	  VERIFICATION_ERROR("invalid local variable type in load");
+	  VERIFICATION_ERROR_WITH_INDEX
+	    ("loading local variable %d which has invalid type");
 	PUSH_TYPE (tmp);
 	goto note_used;
 	case OPCODE_istore:  type = int_type_node;  goto general_store;
@@ -687,7 +695,8 @@ verify_jvm_instructions (jcf, byte_ops, 
 	    || (index + TYPE_IS_WIDE (type)
 		>= DECL_MAX_LOCALS (current_function_decl)))
 	  {
-	    VERIFICATION_ERROR ("invalid local variable index in store");
+	    VERIFICATION_ERROR_WITH_INDEX
+	      ("invalid local variable index %d in store");
 	    return 0;
 	  }
 	POP_TYPE_CONV (type, type, NULL);
@@ -1409,6 +1418,10 @@ verify_jvm_instructions (jcf, byte_ops, 
  bad_pc:
   message = "program counter out of range";
   goto verify_error;
+ error_with_index:
+  error ("verification error at PC=%d", oldpc);
+  error (message, index);
+  return 0;
  verify_error:
   error ("verification error at PC=%d", oldpc);
   error ("%s", message);
-- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/~per/