Re: gas dwarf2 assert failure for misaligned sections?

[DJ Delorie <dj at redhat dot com>]

> I guess we should be emitting a normal error here rather than using
> an assert.

I tried to get the right file/line info, but by the time we're
encoding dwarf2 info (esp wrt relaxing the dwarf2 frags), we've lost
track of where the error really occurred.  This patch at least prints
a user-readable error, and simplifies the existing code a bit too.  I
don't like the message text, but it's the best I could come up with.

2002-11-26  DJ Delorie  <dj@redhat.com.

	* dwarf2dbg.c (scale_addr_delta): New.
	(size_inc_line_addr): Use it.
	(emit_inc_line_addr): Use it.

Index: dwarf2dbg.c
===================================================================
RCS file: /cvs/src/src/gas/dwarf2dbg.c,v
retrieving revision 1.55
diff -p -3 -r1.55 dwarf2dbg.c
*** dwarf2dbg.c	18 Nov 2002 21:08:52 -0000	1.55
--- dwarf2dbg.c	26 Nov 2002 21:15:42 -0000
*************** static void out_debug_line PARAMS ((segT
*** 174,179 ****
--- 174,180 ----
  static void out_debug_aranges PARAMS ((segT, segT));
  static void out_debug_abbrev PARAMS ((segT));
  static void out_debug_info PARAMS ((segT, segT, segT));
+ static void scale_addr_delta PARAMS ((int *));
  
  /* Find or create an entry for SEG+SUBSEG in ALL_SEGS.  */
  
*************** out_set_addr (seg, frag, ofs)
*** 596,601 ****
--- 597,623 ----
    emit_expr (&expr, sizeof_address);
  }
  
+ #if DWARF2_LINE_MIN_INSN_LENGTH > 1
+ static void
+ scale_addr_delta (addr_delta)
+      int *addr_delta;
+ {
+   static int printed_this = 0;
+   if (*addr_delta % DWARF2_LINE_MIN_INSN_LENGTH != 0)
+     {
+       if (!printed_this)
+ 	as_bad("unaligned opcodes detected in executable segment");
+       printed_this = 1;
+       /* This just lets us continue processing, to catch other errors
+ 	 and such.  */
+       *addr_delta -= *addr_delta % DWARF2_LINE_MIN_INSN_LENGTH;
+     }
+   *addr_delta /= DWARF2_LINE_MIN_INSN_LENGTH;
+ }
+ #else
+ #define scale_addr_delta(A)
+ #endif
+ 
  /* Encode a pair of line and address skips as efficiently as possible.
     Note that the line skip is signed, whereas the address skip is unsigned.
  
*************** size_inc_line_addr (line_delta, addr_del
*** 612,621 ****
    int len = 0;
  
    /* Scale the address delta by the minimum instruction length.  */
! #if DWARF2_LINE_MIN_INSN_LENGTH > 1
!   assert (addr_delta % DWARF2_LINE_MIN_INSN_LENGTH == 0);
!   addr_delta /= DWARF2_LINE_MIN_INSN_LENGTH;
! #endif
  
    /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence.
       We cannot use special opcodes here, since we want the end_sequence
--- 634,640 ----
    int len = 0;
  
    /* Scale the address delta by the minimum instruction length.  */
!   scale_addr_delta (&addr_delta);
  
    /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence.
       We cannot use special opcodes here, since we want the end_sequence
*************** emit_inc_line_addr (line_delta, addr_del
*** 678,688 ****
    int need_copy = 0;
    char *end = p + len;
  
- #if DWARF2_LINE_MIN_INSN_LENGTH > 1
    /* Scale the address delta by the minimum instruction length.  */
!   assert (addr_delta % DWARF2_LINE_MIN_INSN_LENGTH == 0);
!   addr_delta /= DWARF2_LINE_MIN_INSN_LENGTH;
! #endif
    /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence.
       We cannot use special opcodes here, since we want the end_sequence
       to emit the matrix entry.  */
--- 697,705 ----
    int need_copy = 0;
    char *end = p + len;
  
    /* Scale the address delta by the minimum instruction length.  */
!   scale_addr_delta (&addr_delta);
! 
    /* INT_MAX is a signal that this is actually a DW_LNE_end_sequence.
       We cannot use special opcodes here, since we want the end_sequence
       to emit the matrix entry.  */