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Java: byte compiler bug fixes


Not all Java bytecode is produced by Java compilers, and some of it
can be downright weird.  I've come across a case where a special
compiler for Java Server Pages generates very bogus-looking code,
where exception handlers recursively invoke themselves.  This can't
work (can it?) but is perfectly legal Java bytecode according to the
spec.  So, I'll allow it but I will generate a warning.

I also found an unrelated bug where one member of struct eh_range
ins't initialized.

Andrew.



2002-08-28  Andrew Haley  <aph@cambridge.redhat.com>

	* verify.c (verify_jvm_instructions): Allow exception handler
	inside code that is being protected, but generate a warning.
	* except.c (link_handler): Initialize `expanded' in new eh_range.
	(binding_depth, is_class_level, current_pc): Declare extern.

Index: except.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/java/except.c,v
retrieving revision 1.28
diff -c -2 -p -r1.28 except.c
*** except.c	4 Aug 2002 22:45:30 -0000	1.28
--- except.c	28 Aug 2002 15:31:12 -0000
*************** struct eh_range whole_range;
*** 62,68 ****
  
  #if defined(DEBUG_JAVA_BINDING_LEVELS)
! int binding_depth;
! int is_class_level;
! int current_pc;
  extern void indent ();
  
--- 62,68 ----
  
  #if defined(DEBUG_JAVA_BINDING_LEVELS)
! extern int binding_depth;
! extern int is_class_level;
! extern int current_pc;
  extern void indent ();
  
*************** link_handler (range, outer)
*** 173,176 ****
--- 173,177 ----
  				     TREE_VALUE (range->handlers));
        h->next_sibling = NULL;
+       h->expanded = 0;
        /* Restart both from the top to avoid having to make this
  	 function smart about reentrancy.  */
Index: verify.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/java/verify.c,v
retrieving revision 1.48
diff -c -2 -p -r1.48 verify.c
*** verify.c	4 Jun 2002 20:32:08 -0000	1.48
--- verify.c	28 Aug 2002 15:31:13 -0000
*************** verify_jvm_instructions (jcf, byte_ops, 
*** 472,476 ****
  	  || end_pc < 0 || end_pc > length || start_pc >= end_pc
  	  || handler_pc < 0 || handler_pc >= length
- 	  || (handler_pc >= start_pc && handler_pc < end_pc)
  	  || ! (instruction_bits [start_pc] & BCODE_INSTRUCTION_START)
  	  || (end_pc < length &&
--- 472,475 ----
*************** verify_jvm_instructions (jcf, byte_ops, 
*** 482,485 ****
--- 481,487 ----
  	  return 0;
  	}
+ 
+       if  (handler_pc >= start_pc && handler_pc < end_pc)
+ 	warning ("exception handler inside code that is being protected");
  
        add_handler (start_pc, end_pc,


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